This article mainly introduces the structure, characteristics, advantages, and disadvantages of OLED display and the differences between LED display and LCD display, by reading this article, you can have a deeper understanding of OLED display， so as to better apply OLED display. If you require LED driver chips, please check the stock with P/N on Quarktwin's official website. What is an OLED display? An OLED display is a solid-state device consisting of thin sheets of organic molecules that emit light when electricity is applied. OLED enables electronic devices to produce brighter, sharper images and consumes less power than traditional conventional LED displays. What are the advantages of OLED displays? The organic plastic layer of OLEDs is thinner, lighter, and more flexible than the crystal layer of LEDs or LCDs. The OLED base layer is made of plastic, while LEDs and LCDs use a glass base layer. OLED is brighter than LED. The OLED organic layer is much thinner than the corresponding inorganic crystal layer in LED, so the OLED conductive layer and emitting layer can be used in a multi-layer structure. In addition, LED and LCD need to use glass as a support, and the glass will absorb part of the light. OLED does not need to use glass. OLED does not need to use the backlighting system in LCD (please check the LCD (liquid crystal display) principle of operation). LCD will work selectively to block certain backlight areas to make the image visible, while OLED is by its light. Because OLEDs do not require backlighting systems, they consume less power than LCDs (most of the power consumed by LCDs is used for backlighting systems). This is especially important for battery-powered devices (such as cell phones). OLEDs are easier to manufacture and can be made in larger sizes. OLEDs are made of plastic, so they can be made into large, thin sheets. Trying to use so many crystals and lay them flat is much more difficult. OLEDs have a wide field of view, up to about 170 degrees. OLEDs can emit light themselves, so the field of view is also much wider. What are the disadvantages of OLED displays? OLED seems to be a flawless technology for all types of displays, but it also has some problems. 1. Lifespan: While red and green OLED films have a long lifespan (10,000-40,000 hours), blue organics have a much shorter lifespan (only about 1,000 hours) according to the current state of the art. 2. Manufacturing cost: OLED's cost is still relatively high. 3. Water failure: OLEDs can be easily damaged if they are exposed to water. What is OLED’s display structure? Base layer (transparent plastic, glass, metal foil) - the base layer is used to support the entire OLED. Anode (transparent) - the anode eliminates electrons (adds electron "holes") as current flows through the device. Organic layer - The organic layer is made up of organic molecules or organic polymers. Conductive layer - This layer consists of organic plastic molecules that transport the "holes" coming from the anode. Polyaniline can be used as the conducting polymer for OLEDs. Emission layer - This layer consists of organic plastic molecules (different from the conductive layer) that transport electrons from the cathode; the light-emitting process takes place in this layer. Polyfluorene may be used as the emitting layer polymer. The cathode (which can be transparent or opaque, depending on the type of OLED) - when a current flows in the device, the cathode injects electrons into the circuit. What are the characteristics of OLED displays? OLED is self-luminous material, with no need to use the backlight board, at the same time, wide viewing angle, uniform picture quality, fast response time, easier to color, with a simple drive circuit to achieve light, and simple process, can be made into a flexible panel, in line with the principle of thin and short, the application range belongs to small and medium-sized panels. Display aspects: active light-emitting, large viewing angle range; fast response time, image stability; high brightness, rich color, and high resolution. Operating conditions: low driving voltage, low energy consumption, can be matched with solar cells, integrated circuits, etc. Wide adaptability: the use of glass substrates can achieve a large-area flat panel display; such as the use of flexible materials as a substrate, can be made into a foldable display. As OLED is an all-solid-state, non-vacuum device, with anti-vibration, low-temperature resistance (-40 ℃), and other characteristics, in the military also has very important applications, such as being used as a tank, aircraft, and other modern weapons display terminal. What is the light-emitting process of OLED displays? 1. The OLED device's battery or power supply will apply a voltage at both ends of the OLED. 2. Current flows from the cathode to the anode and through the organic layer (current refers to the flow of electrons). The cathode outputs electrons to the organic molecule emitting layer. The anode absorbs the electrons coming from the conduction layer of the organic molecule. (This can be considered as the output of holes from the anode to the conduction layer, and both have equal effect effects.) 3. At the junction of the emitting and conduction layers, electrons will combine with holes. When the electron encounters a hole, it will fill the hole (it will fall into one of the energy levels in the atom that is missing the electron). When this process occurs, the electron releases energy in the form of a photon. (Please check the article on the principle of light). 4. OLEDs emit light 5. The color of the light depends on the type of organic molecules in the emitting layer. Manufacturers will place several organic films on the same OLED to constitute a color display. 6. The brightness or intensity of light depends on the size of the applied current. The higher the current, the higher the brightness of the light. What are the differences between LED displays and LCDs? From the display effect Led display is a combination of diode display, can be self-luminous, display effect will be more full of integration, and led display can also adjust the brightness, combined with different environmental needs to adjust the brightness promptly. And LCD is composed of liquid crystal, with the help of refracted light to light, so its display effect is not so natural, and the color saturation is also lacking. From the power consumption situation Led display in energy saving this piece or more convincing, the led display can all show the picture, but also can only open some of the pixel display, low power consumption, more energy efficient; and LCD is the opposite, with high power consumption because LCD can only do all open or all off. From the seam difficulty Led display is the use of the unit board, the unit board will have different sizes, spacing lamp beads, splicing large screen, then, relatively simple, no splicing obstacles. And LCD splicing words need to consider the splicing bezel problem, relatively difficult. From the waterproof and sunlight look The structure of the led display has a waterproof and sunproof function, will not be affected by extreme weather, so we will find whether indoor or outdoor will have an led display, and LCD in this regard is relatively lacking, so the LC display will used indoors, so it can also help it avoid some risks. From the application scene Led display is usually used for outdoor publicity, indoor display (such as some meetings, conferences, command, and control), etc., application scenes more; and LCD is usually used for indoor, especially some need to look at the scene close, such as corporate exhibition hall, small conference room, etc. LED display and LCD, which is better? If it is outdoor publicity, the led display will be better, because it is waterproof and sunproof, which will be more conducive to the external environment display. If you are more interested in price, then an LCD display will be slightly better, but depending on your specific scene, such as some scenes are not suitable for LCD, then it is best to choose the led display. If you look at energy saving, that led display is better, because it is relatively low power consumption.
If you want to learn more, please visit our website HumenChem.
#OLED displays-03-22This article mainly introduces the advantages of solar LED street lights, lighting principles, applications, and factors affecting the price of LED street lights, by reading this article, you can have a more in-depth understanding of solar LED, so as to better apply solar LED lights. The advantages of solar LED streetlights Solar lights use sunlight as the energy source, solar panels charge the battery during the day, and the battery supplies power to the light source at night, without complicated and expensive pipeline laying, and can be adjusted at will to the layout of the lamps, safe, energy-saving and non-polluting, no manual operation work stable and reliable, saving electricity costs and maintenance-free. Energy saving and environmental protection In the past, ordinary street lights contain some harmful substances, as well as harmful rays in the spectrum. LED street lights are mercury-free, UV-free, radiation-free, and more conducive to environmental protection and human eye health. Low input cost The traditional street light in the paving project is much more complicated than LED street light, not only digging holes, and leading the way, labor and materials are very expensive, and the electricity cost of traditional street light is very high, and the cost is also higher. LED street light does not need digging holes, or laying cables, saving a lot of labor and material costs. The lighting function is stronger Compared with traditional street lights, LED street lights' lighting function is stronger. LED street lights' light color is uniform, it does not add a lens and does not sacrifice uniform light color to improve the brightness, of a 60W LED street light, its brightness can reach 250 W high-pressure sodium lamp illumination, and can save a lot of electricity. Low power consumption and long life Under the same brightness, the power consumption is one-tenth of an incandescent lamp, one-third of a fluorescent lamp, but the life is 50 times of an incandescent lamp, 20 times of a fluorescent lamp, is the fourth generation of lighting products after the incandescent lamp, fluorescent lamp, gas discharge lamp. Safer installation and use The installation of ordinary street lights is complicated, the use of the process may also occur in fire, electric shock, and other accidents. And LED street lights will be more at ease, in the installation and use can also greatly reduce safety risks. What is the principle of solar LED high-power street light lighting? Solar energy is the most direct and universal and cleanest energy on earth, solar energy is a huge amount of renewable energy, the daily radiation energy reaching the earth's surface is approximately equal to 250 million barrels of oil, which can be said to be inexhaustible. Then energy-saving lamps but also energy-saving 1/4, which is a greater reform of the solid light source. Solar LED lighting integrates the advantages of solar energy and LED. The system consists of a solar cell part (including bracket), LED lamp head, control box (with controller, battery), and light pole several parts; the solar panel's luminous efficiency of 127Wp/m2, high efficiency, the system's wind-resistant design is very favorable; lamp head part to 1W white LED and 1W yellow LED integrated into the printed circuit board arranged as a certain spacing of the dot matrix as a plane light source. light source. The control box is made of stainless steel, which is beautiful and durable; the maintenance-free lead-acid battery and charge/discharge controller is placed inside the control box. The system uses a valve-regulated sealed lead-acid battery, which is also called a "maintenance-free battery" because of its little maintenance, which is conducive to the reduction of system maintenance costs; the charge/discharge controller is designed to take into account both functional (with light control, time control, overcharge protection, over-discharge protection, and reverse connection protection, etc.) and cost control to achieve a high-cost performance ratio. What is the principle of solar LED lighting? The working principle of the system is simple, using the photovoltaic effect of solar cells made of solar panels during the day to receive solar radiation and converted it into electrical energy output, through the charge and discharge controller stored in the battery, at night when the illumination gradually reduced to about 10lux, solar panels open circuit voltage of about 4.5V, the charge and discharge controller detects this voltage value after the action, the battery discharges the lamp head. After the battery is discharged for 8.5 hours, the charge/discharge controller acts, and the battery is discharged. The main role of the charge/discharge controller is to protect the battery. If you require LED driver chips, please check the stock with P/N on Quarktwin's official website. What need to pay attention to when selecting solar modules? The average annual radiation in the Guangzhou area in the past 20 years is 107.7 kcal/cm2, and the peak sunshine hours in the Guangzhou area is about 3.424h by a simple calculation. The daily power consumption of the load = = 12.2AH The total charging current of the solar module required = 1.05 × 12.2 × ÷ (3.424 × 0.85) = 5.9A Here, the design minimum number of days between two consecutive cloudy days is 20 days, 1.05 is the solar module system integrated loss factor, and 0.85 is the battery charging efficiency. Minimum total power number of solar modules = 17.2 x 5.9 = 102W The selection of a standard battery module with a peak output power of 110Wp and a single 55Wp should ensure the normal operation of the street light system in most cases throughout the year. Selection and application of solar LED streetlights With the sustainable use of green solar energy resources, coupled with the energy saving and environmental protection of LED, as well as the remarkable features of freestanding solar LED street lights that do not require wire laying, solar LED street lights are becoming the best choice for more municipal road renovation and expansion projects, with good promotion and application space in squares, campuses, parks, schools, streets, residential areas, factories and remote areas where electricity is scarce. Among them, the solar panel is the core part of solar street light, and also the highest-value part of a solar street light. Its role is to convert the sun's radiation power into electricity or send it to the battery for storage. Among the many solar cells, the more common and practical are monocrystalline silicon solar cells, polycrystalline silicon solar cells, and amorphous silicon solar cells. In the east and west of the region where sunlight is abundant and good, polycrystalline silicon solar cells are mostly used because the production process of polycrystalline silicon solar cells is relatively simple and the price is lower than monocrystalline. In the southern region where there are more rainy days and relatively less sunshine, it is better to use monocrystalline solar cells, because the performance parameters of monocrystalline solar cells are more stable. Amorphous silicon solar cells are better in the case of insufficient outdoor sunlight because amorphous silicon solar cells have lower requirements for sunlight conditions. What factors affect the price of solar LED streetlights? Solar LED street light is actually not a standard product as we understand, more often than not it is a non-standard custom-made. There are many categories of street lights from style, height, configuration, material, etc., so there is no uniform quotation, and the parameters given by the design institute of each street light purchasing place are not the same. Solar street light manufacturers to solar LED street lights for quotation, not only to consider the height of the solar street light pole but also to consider the following points. Solar LED street light installation area of the insolation coefficient. The sunshine factor is the average length of sunlight, each region's sunshine factor is different, so each region's solar street light configuration can not be the same, the configuration is not the same, and solar LED street light quotes are certainly not the same. Solar street light manufacturers will match the most reasonable solar street light configuration according to the local insolation factor and the consumer's lighting needs. Solar LED street light power size, the length of time to light up. This will lead to solar LED street light configuration is not the same, and the natural offer is not the same. Consumers of solar LED street light quality required, a long warranty period. The higher the quality, the longer the warranty, and solar street light manufacturers' production costs and after-sales service time are bound to increase, which will certainly lead to solar LED street light prices becoming higher, the overall offer higher. Solar LED street light by virtue of the photovoltaic effect to generate electricity, are green and environmentally friendly and has been rapidly popularized and promoted in a wide range of areas in China. At the same time, we also categorize it as a livelihood project, it is recommended that according to their own needs and the geographical conditions of the region, to ensure the quality of reliable premises, with a reasonable price to buy cost-effective solar LED street lights.
#Solar LED-03-22This article focuses on the advantages and disadvantages of high-power LEDs and the problems in high-power Led lighting. By reading this article, you can better understand high-power LEDs so that you can better apply them. If you require LED control chips, please check the stock with P/N on Quarktwin's official website. What are the advantages of high-power LEDs? With High-power LED features and comparison with other light sources LED is called a "green light source" deservedly. In the lighting industry, the analysis of its comparison with traditional light sources, certain aspects show the advantages of difficult to replace: LED as a light source for lighting has the following advantages. Low power consumption: luminous efficacy of 75lm / W LED than the same brightness of the incandescent lamp power consumption is reduced by about 80%. Long life: product life of up to 50,000 hours, 24 hours of continuous lighting available for 7 years. Brightness and color dynamic control easy: can achieve continuous brightness adjustable, high color purity can achieve dynamic color change and digital control. Flexible shape and size: can achieve organic integration with the building, to achieve the effect of only seeing the light without the light. Environmental protection: no harmful metal mercury, no infrared and ultraviolet radiation. Color: Bright saturated, pure, no filter, available red, green, and blue elements into a variety of different colors, can achieve the multi-variable, change-by-change, mixed light effect, excellent color rendering effect. Setting so many advantages in one, or more lets us feel to vigorously promoting the use of LED is a very valuable work. But LED and other light sources also have shortcomings, such as low color rendering in white lighting. Currently, with yellow phosphor and blue light generated by the white LED, its color rendering index is about 80. as general lighting can be, but for some color discrimination requirements of high places is insufficient. Although the color rendering index can be increased to 90 or higher by adding appropriate red phosphor and other methods, there is still a gap compared with 99 for incandescent lamps, and its efficiency will be affected. Color rendering can also be improved through the RGB color mixing process, but the technology needs to do more work in the popularization of applications, so the color rendering, and LED also need needs to be improved. As for the price is too high, a large one-time investment, in fact, from a comprehensive cost consideration, many occasions to use LED or save a lot of costs. Table 1 below is a comparison of the life of incandescent, fluorescent, ordinary LED, and high-power LED, from the table below, can be seen, high-power LED has a great advantage in life, from incandescent and fluorescent lamps in many technical aspects to improve the space has been very small. What are the disadvantages of high power Led? High-power LEDs require thermal management, which greatly increases the cost of LEDs. An expensive addition to the design process is the heat sink. Heat sinks can be made from a variety of metallic materials, which include both relatively aluminum and materials with better conductivity but are more expensive (such as copper and silver). These expensive materials may lead to high-power product cost increase of $ 1-10, and standard LED devices can avoid this cost increase. Due to high-power white LED conversion efficiency is still low, the luminous flux is small, the cost is high, the white light is easy to discolor over time, heat dissipation and other factors, so high-power white LED short-term applications are mainly some special areas of special work lamps and lanterns, medium and long-term goals to be general lighting field. High-power LED problems in Led lighting LED color difference problem In the application of a single LED, there is no problem of chromatic aberration, but if a large number of LEDs are put into use together or light with multiple LEDs at the same time, the problem of chromatic aberration will come to the fore. First of all, a group of lamps, if a glance to see the color of the light inconsistent, I think the happy mood will have to play a discount. Although the same as LUXEON LED color temperature into eight military zones, and then in each military zone right into several cells, to a certain extent will be a wide range of color differences for control, the same color zone in the same batch of LED still exist differences, and this difference still can not escape the naked eye provocation. LED insulation problems Not to say that we are the first to find LED insulation problems, but at least the big-name manufacturers are surprised by our questioning. So far to still not solve the fundamental problem, only to take remedial measures, such as the use of aluminum substrate to deal with insulation (the initial aluminum substrate did not do insulation, now almost all do) may feel incomprehensible. A single LED is not insulated, the impact is not large, and multiple in series when there is a problem. LED pulse resistance problem This problem is still controversial with the manufacturer, in my practical application does exist, mainly in the cold pulse, that is, at the moment of power, a few LEDs in the cold state on the moment of power that breakdown or disconnect. I think it is not static electricity or high voltage (power-on voltage in the range). The LED light-emitting angle of the problem As various manufacturers of LED lens package is not the same even if the same luminous angle (nominal angle), the effect is not the same, making it more difficult to select the spotlight, but still not universal. LED potential blindness hidden danger LED light-emitting point is too concentrated so that the center point of super bright, so it is easy to hurt the human eye, although some lighting manufacturers to do efforts in this regard, but due to the lag of regulations, also only for human moral issues. LED heat problem Theoretically speaking, LED does not have heat, but due to the immaturity of the current technology, LED heat is well known, I do not want to say more. LED efficiency is low (luminous rate) The current LED electrical conversion efficiency is too low (due to the absence of instrumentation testing, dare not give specific data). LED brightness is not enough Insufficient brightness, making the current LED in the lighting industry can only play a supporting role, mainly for decoration. LED light decay and life At present, mainland Taiwan's LED light failure and liver problems are more serious, not to mention that the big-name manufacturers such as LUXEON claim 100,000 hours, I'm afraid that only their psychological clarity, coupled with the good or bad thermal solutions, matching the driver may affect the LED light failure and life, so 100,000 hours is only a selling point too! The LED driver power supply problem Most of the current drive lines are borrowed from switching power supplies, of course, there are a very small number of lines specifically for LED drives, but the effect is the same because the LED must be a DC drive, take constant current control, making the drive line is quite large, can not be compared with the electronic transformer, and the efficiency is relatively low, reaching 80% to be considered good (single still can not reach). In addition, the manufacturer in pursuit of applicability, claim claiming that a driver can take a dozen random connections (one, two are available), in fact, this is a misconception, although it is constant current, too high a starting voltage will often kill the LED in an instant. LED modeling is limited Due to the characteristics of the LED single-sided light, making the LED lamps and lanterns shape is subject to certain restrictions. LED unit price is too high An imported 1W-3W LED mostly to about 3 U.S. dollars, and domestic also to more than 10 (poor quality, no intellectual property rights) 6 LED lamps and lanterns sold to consumers, almost more than 1,000 yuan, please ask whether you want to buy color TV or buy lamps.
#High-power LED-03-22This article mainly introduces the four key issues of white LED luminous efficiency improvement. By reading this article, you can clearly understand how to properly improve the luminous efficiency of white LED. If you want to know more information about LEDs, check out the other articles in the LED list on Quarktwin's official website. Solve the problem of heat dissipation in the package is the fundamental method As a result of increasing the power will instead cause the thermal impedance of the package to drop sharply to below 10K/W, so the foreign industry has developed high-temperature white LEDs to try to improve the above problem, but in fact, the heat of high-power LEDs is tens of times higher than low-power LEDs, and the temperature rise will also make the luminous efficiency dropped significantly, even if the packaging technology allows high heat, but the LED chip bonding temperature is Even if the packaging technology allows high heat, but the LED chip bonding temperature is likely to exceed the allowable value, the industry finally realized that the solution to the problem of heat dissipation in the package is the fundamental method. Regarding the service life of LEDs, such as switching to silicon encapsulation materials and ceramic encapsulation materials, LED service life can be increased by a single digit, especially the white LED light spectrum contains wavelengths lower than 450nm short wavelength light, traditional epoxy resin encapsulation materials are very easy to be destroyed by short wavelength light, high power white LEDs of large light volume to accelerate the deterioration of the encapsulation materials, according to the industry test results show Continuous lighting less than 10,000 hours, high power white LED brightness has been reduced by more than half, simply can not meet the basic requirements of the long life of the lighting source. LED luminous efficiency, improve the chip structure and packaging structure and can reach the same level with low-power white LED, the main reason is that the current density increased by more than 2 times, not only is not easy to take out the light from large chips, the results will instead cause luminous efficiency than the dilemma of low-power white LED, if the chip electrode structure, theoretically can solve the above-mentioned light problem. To reduce the thermal impedance, and improve heat dissipation problems Regarding the uniformity of light-emitting characteristics, it is generally believed that as long as the white LED fluorescent material concentration uniformity and fluorescent body production technology, should be able to overcome the above problems. As mentioned above to improve the applied power at the same time, we must try to reduce the thermal impedance and improve the heat dissipation problem, the specific content is: reduce the thermal impedance from the chip to the package, suppress the thermal impedance from the package to the printed circuit substrate, and improve the smoothness of the heat dissipation of the chip. In order to reduce the thermal impedance, many foreign LED manufacturers will be located in the LED chip made of copper and ceramic material cooling fins (heatsink) surface, followed by welding the printed circuit board with heat dissipation wires, connected to the use of cooling fans forced air cooling fins, according to the German OSRAMOp to semiconductor experimental results confirm that The above structure of the LED chip to the welding point of the thermal impedance can be reduced by 9K / W, about 1/6 of the traditional LED, after the packaging of the LED applied 2W of power, the LED chip bonding temperature is 18K higher than the welding point, even if the printed circuit board temperature rises to 500C, the bonding temperature is only about 700C at most. Compared to the previous thermal impedance once reduced, the LED chip The bonding temperature of the LED chip will be affected by the temperature of the printed circuit board, so it is necessary to try to reduce the temperature of the LED chip, in other words, reduce the thermal impedance of the LED chip to the soldering point, can effectively reduce the burden of LED chip cooling operations. Conversely, even if the white LED has a structure to suppress thermal impedance if the heat can not be conducted from the package to the printed circuit board, the LED temperature rise as a result of the luminous efficiency will drop sharply, so Matsushita Electric developed printed circuit board and package integration technology, the company will be 1mm square blue LED flip-chip way to pack on a ceramic substrate, and then the ceramic substrate will be posted on the According to Panasonic, the thermal impedance of the module as a whole, including the printed circuit board, is about 15K/W. Various industry players show their thermal design skills Due to the close adhesion between the heat sink fins and the printed circuit board, the design of the printed circuit board has become very complicated, given this, lighting equipment and LED packaging manufacturers such as Lumileds and CITIZEN in Japan have developed simple heat sink technology for high power LEDs. According to CITIZEN, although the 30K/W thermal impedance from the LED chip's junction point to the thermal fins is larger than that of OSRAM's 9K/W, and the room temperature in a general environment will increase the thermal impedance by about 1W, the white LED module can be cooled even in a conventional printed circuit board without a cooling fan to force air cooling. However, the white LED module can be used continuously without a cooling fan. Lumileds began sample shipments of high-power LED chips in , the bonding temperature tolerance is as high as +C, 600C higher than other companies of the same level of products, the use of traditional RF4 printed circuit board package, the ambient temperature of 400C range can be input equivalent to 1.5W power current (about 400mA). So Lumileds and CITIZEN make to take to increase the joint tolerance temperature, German OSRAM company the LED chip located in the heat sink fin surface, to achieve a 9K / W ultra-low thermal impedance record, the record as OSRAM past development of the same level of thermal impedance reduced by 40%, it is worth mentioning is that the LED module packaging, using the same traditional method of flip-chip It is worth mentioning that the LED module is packaged using the same flip-chip method as the traditional method, but when the LED module is joined with the thermal fin, the closest LED chip light-emitting layer is chosen as the joint surface, so that the heat from the light-emitting layer can be discharged with the shortest distance conduction. In , Toshiba Lighting once in 400mm square aluminum alloy surface, laying luminous efficiency of 60lm / W low thermal impedance white LED, no co, oiling fan, and other special cooling components under the premise of the pilot production of the light beam for 300lm LED module, due to Toshiba Lighting has a wealth of experience in pilot production, so the company said that due to the progress of simulation analysis technology. After more than 60lm / W white LED, can easily use almond ps, frames to improve thermal conductivity, or the use of cooling fans to force air-cooled design of lighting equipment heat dissipation, do not require special cooling technology module structure can also be used white LED. Change the packaging material to inhibit the rate of material deterioration and light penetration reduction The long life of LED, LED manufacturers take countermeasures to change the packaging material, while the fluorescent material dispersed in the packaging material, especially the silicon packaging material than the traditional blue, near-ultraviolet LED chip above the epoxy resin packaging material, can more effectively inhibit material deterioration and light penetration rate reduction rate. As the epoxy resin absorbs up to 45% of the light wavelength of 400~450nm, the silicon encapsulation material is less than 1%, the time of halving the glow epoxy resin is less than 10,000 hours, the silicon encapsulation material can be extended to about 40,000 hours, almost the same as the design life of the lighting equipment, which means that the lighting equipment does not need to replace the white LED during use. However, silicone resin is a highly flexible material, and the processing must use production technology that will not scratch the surface of silicone resin, in addition to the process of silicone resin very easy to adheres to dust, so the future need needs to develop technologies that can improve the surface characteristics. Although the silicon encapsulation material can ensure the service life of the LED 40,000 hours, however, the lighting equipment industry is a different view, the main argument is the service life of traditional incandescent and fluorescent lamps, is defined as "brightness reduced to less than 30%", the brightness halved the time for 40,000 hours of LED, if converted into brightness reduced to 30% If converted to reduce the brightness to less than 30%, only about 20,000 hours left. At present, there are two countermeasures to extend the service life of the components, respectively, to suppress the overall temperature rise of white LEDs, and stop using the resin packaging method. It is generally believed that if the above two life extension measures are thoroughly implemented, the brightness of 30% of 40,000 hours can be achieved. The main reason is that the high temperature of the encapsulation resin, coupled with strong light irradiation will rapidly deteriorate, by the Arrhenius rule of lowering the temperature of 100C life will be extended by two times.
#White LED luminous efficiency-03-22This article introduces the main characteristics of the light source and the comparison of conventional white LEDs and power white LEDs in the application of signal lights, by reading this article, you can have a deeper understanding of white LEDs, so as to better apply white LEDs What are the main characteristics of the light source? To evaluate a light source, you generally need to look at several characteristics: power, light efficiency, light characteristics, and price. power is the common input power of this light source, such as a 100W incandescent lamp, is its input power is 100W. each light source can cover a wide range of power, here we only compare the common power range. Light efficiency is the ability of a light source to convert electrical energy or other inputs into light energy, light energy we use luminous flux as the evaluation standard, and the unit of this efficiency is (lumens/watt), indicating the ability of the light source to convert each watt of energy into lumens. Light characteristics refer to the color of the light source, light-emitting area, light dispersion angle, and other characteristics. Light characteristics often determine the application of a light source, such as laser directional goods, which can be used for distance measurement, and fluorescent lamps dispersion goods, suitable for indoor lighting, etc. Because of the great difference in power, we approximate the price per lumens needed to make a rough comparison, while the difference in power consumption caused by different light efficiency, will be briefly analyzed later in the article. In addition to the light characteristics and other characteristics, LED is slightly advantageous, in terms of power, and price can be said to be at a complete disadvantage. Especially the price is the most fatal factor limiting the current scope of the application of LED. Power limitations lead to LED can not be used for a wide range of lighting, such as in airports, construction sites, and even indoor lighting, LED can not be compared with fluorescent lamps. In practice, when the lighting equipment is more powerful, then the power consumption is not negligible cost. But in front of fluorescent lamps and HIDs with higher luminous efficiency, LEDs do not take any advantage. In the power and price before a breakthrough, the promotion of LED lighting can be described as a difficult step. Although many cities have been investing in the construction of some public LED lighting equipment, in the current situation, this behavior is just a waste of taxpayer money. In addition, the decorative colored LED relatively speaking, the advantages are more obvious, because the ordinary light source becomes a colored light source, generally speaking, its luminous efficiency will be reduced, while the LED in the field of colored light efficiency has almost an absolute advantage. But unfortunately, neon lights as traditional decorative lamps and lanterns, and their cost performance has reached a fairly high level, LED want to replace them is not a simple matter. LED's only strength lies in the lighting of small, low-voltage devices, such as cell phones， dc, and other home digital products. These products are expensive, so LED's relatively expensive defects become less obvious. If you require LED driver chips, please check the stock with P/N on Quarktwin's official website. Comparison between Conventional white LED and power white LED in the signal light application 1. The materials used are different. General white LEDs use epoxy resin as the mounting board, while power white LEDs need to use aluminum-based circuit boards (MCPCB). 2. Production process is different. General white LEDs can use wave soldering or manual welding, while the power white LEDs need to use an SMD welding machine. 3. The supporting electronic components are different. Because the welding process is different, so with the general white LED supporting electronic components are also required to use wave soldering or manual welding of general components, and power white LED supporting electronic components are SMD components. 4. The degree of automation is not the same. Because the production process is not the same, SMD production of a high degree of automation, you can use the assembly line; and general white LED and general components due to the appearance, and structure differences, so a considerable part of the work (such as inserting the tube, etc.) are required to be completed manually. This leads to the processing quality of the two is not the same. 5. Processing performance guarantee is not the same. As electrostatic protection and other measures are important factors affecting the service life of white LEDs, and general white LED production is not highly automated, so electrostatic protection and other measures are more difficult to implement. And the power white LED production process is easier to ensure its integrity. 6. The degree of integration is not the same. Because of the power white LED SMD process, its electronic components can be highly integrated, you can make the light board and power supply, etc. very small, while the general white LED and its supporting components are difficult to achieve this goal. 7. Different structural design requirements. Although the general white LED power is small, a single white LED heat less (of course, these white LEDs to withstand the heat is also low, and the heat dissipation effect is also poor), but its distribution in the entire light-emitting surface, so its heat dissipation improvement measures are difficult to implement. The power white LED is relatively concentrated, and the use of SMD technology is installed on the aluminum substrate, so it is easy to design a heat sink, white LED light board can be installed directly on it to improve its thermal effect. 8. The light distribution design requirements are not the same. General white LED because of the number of tubes used, and uniformly distributed throughout the light-emitting area, so the light distribution needs to correspond to the white LED one by one. And power white LED tube number used less, generally, 300mm signal lights using 12 or even 8 LEDs can meet the requirements, so the entire light plate placed near the axis of the light-emitting surface, in the light distribution will be approximated as a concentrated light source to design. 9. The use of the effect is not the same. General white LED because the light emitted is distributed throughout the range of light-emitting surfaces, the spacing between each other is large, so the effect of the projection on the light-emitting surface is relatively obvious to see the dotted distribution of light-emitting sources. And because of the white LED light source itself in the distribution of light intensity in the strong and weak, coupled with the package often exists in the spot uneven phenomenon, the entire light-emitting surface is bound to exist between light and dark, while the light distribution is used in a one-to-one correspondence, so in the case of one or a string of white LED failure will appear dark spot, thus affecting the overall signal light efficiency and graphics. High-power white LEDs are relatively concentrated and are approximated as a concentrated light source in the light distribution, so the above defects can be avoided. 10. Service life is not the same. As the power white LED has the following characteristics, you can extend the service life. Fewer tubes, and fewer branches, so it is easy to use the branch constant-current power supply to ensure that each white LED has the same power supply environment, even if one of the individual failures, will not affect the supply current of other white LEDs. With good heat dissipation, the node temperature will be relatively lower, so the life will be extended. The allowed operating current is larger, more than ten times the general white LEDs, so the current control fluctuations of a few milliamps, the high-power white LEDs will not be affected at all. Therefore, it is less dependent on the precise control of the power supply, but also conducive to extending the service life.
#White LED-03-21This article introduces the difference between LED light sources and LED luminaire performance. By reading this article, you can understand clearly the difference between LED light source and LED luminaire performance, so that you can better apply them. With the concept of light efficiency also used in LED lamps and lanterns, many LED lamps and lanterns also joined the flood of light efficiency race, manufacturers are ignoring the differences between LED light sources and LED lamps and lanterns product features, only to light efficiency as the benchmark for the performance of lamps and lanterns, the simple pursuit of high light efficiency indicators, ignoring its LED lamps and lanterns as a system should meet the reliability, color quality and visual comfort and other characteristics, resulting in the current Domestic LED lighting market chasing light efficiency of the wind prevails, municipal projects and semiconductor lighting pilot demonstration projects in the use of the so-called "high luminous efficacy LED lamps and lanterns" often fail to achieve its intended purpose of energy saving and emission reduction of the use of the effect, resulting in a greater negative effect. For the current lighting market, this paper explains the difference between LED light sources and LED lamps and lanterns efficiency. This reveals the reason why the wind of chasing light efficiency spreads from LED light sources to LED lamps and lanterns. Emphasizes that LED lighting products should pay attention to the efficiency of the lamps and lanterns and other performance requirements of coordination, lighting efficiency should be built based on meeting the performance of LED lamps and lanterns. If you require a LED control chip, please check the stock with PN on Quarktwin's official website. Luminous efficacy is the classic performance indicator of light source products In terms of the light source, luminous efficiency is a classic indicator, the emergence of each new light source is directly related to its higher luminous efficiency, so the luminous efficiency has become an important indicator of the performance of the LED light source without exception. Of course, other performance indicators of light sources include color rendering index, color coordinates, color temperature and life, and so on. For the use of traditional light source lamps and lanterns, the luminous rate of the lamps and lanterns, that is, the ability of the lamps and lanterns to convert the luminous flux of the light source is the classic indicator of the performance of the lamps and lanterns. As the performance parameters of LED light source has not yet reached the degree of standardization, and many lamps and lanterns using LED light source are not replaceable, s the concept of light efficiency is also used in LED lighting products. The differences between LED light sources and LED lamps and lanterns' efficiency When the LED light source and LED lamps and lanterns are used as performance evaluation indicators, we first analyze the connotations and differences between the two to understand the performance of LED lamps and lanterns and use the correct terminology to evaluate the luminous efficacy of LED light sources and LED lamps and lanterns. LED light source luminous efficacy and the concept of LED lighting efficiency LED light source luminous efficacy (luminous efficacy of a source) is defined as the ratio of the luminous flux emitted by the light source to the electrical power it consumes. LED luminaire efficacy (luminaire efficacy) is defined as the ratio of the initial total luminous flux emitted by the luminaire to the power consumed by the luminaire under the claimed conditions of use of the luminaire, in units of lm/W. "Luminaire efficacy" is used to evaluate the LED light source, "efficacy" is used to evaluate the LED lamps and lanterns, LED light source luminaire efficacy and LED lamps and lanterns efficacy is said to be the efficiency of the conversion of electrical energy into light energy is to describe the energy-saving characteristics of lighting products indicators, but its connotation is different. Different luminous flux LED light source luminous efficacy of the light source luminous flux refers to the bare light source (not yet installed in the state of the lamp) emitted luminous flux. Which LED light source can be integrated LED lamps or integrated LED modules, semi-integrated LED lamps or semi-integrated LED modules, or non-integrated LED lamps or non-integrated LED modules? The molecular luminous flux in the LED luminaire efficacy is the luminous flux emitted by the luminaire after the light source is loaded into the luminaire while using the required LED control device or LED control device power supply. Where the LED control device or the power supply for the LED control device may be integral, built-in, or stand-alone. Luminaires using LED light sources may use reflectors and diffusion panels. The light source loaded into the luminaire may be a single light source or a collection of multiple light sources, but due to the efficiency loss caused by the interaction of thermal and electrical energy, as well as the efficiency of the luminaire optical system, the luminous flux of the LED luminaire is not equal to the luminous flux of the LED light source or its simple accumulation. LED light source luminous efficacy in the luminous flux and luminous flux in the luminaire efficiency of the measurement state is different, the former is measured in the pulse state, and the latter is measured in the steady state. LED light source luminous efficacy in the light is not directional, as long as the light can be issued, the southeast and northwest do not matter. While the light in the LED luminaire efficiency is directional, light needs to be sent to the user area. In the case of using the same LED light source, the luminous flux of LED lamps and lanterns is less than the luminous flux of the LED light source. Different input power The denominator in the luminous efficiency of LED light sources is not the same as the denominator in the efficiency of LED luminaires. For example, for non-integrated LED modules, the electrical power consumed by the LED light source refers only to the power consumed by the LED module, excluding the power consumed by the LED control device. the electrical power consumed in the LED luminaire efficiency refers to the input power of the luminaire, including not only the LED light source but also the power consumed by the LED control device. the electrical power consumed by the LED luminaire is greater than the electrical power consumed by the LED light source. The electrical power consumed by the LED luminaire is greater than that consumed by the LED light source. LED luminaire performance and LED light source luminous efficiency of the relationship Due to the different ranges of luminous flux and electrical power involved, resulting in LED light source luminous efficacy i different from LED lamps and lanterns, light source luminous efficacy is much greater than the luminous efficacy. One because the LED into the lamps and lanterns, junction temperature increases, and light output is reduced (heat loss); second because the light source into the lamps and lanterns, and the use of LED control device or its power supply after the existence of system losses; third is the loss of light after the optical system of the lamps and lanterns, that is, the efficiency of the lamps and lanterns (light loss). Luminaire efficiency = light source luminous efficiency × (1 - heat loss after entering the luminaire) % × (1 - system loss) × (1 - light loss after entering the luminaire) % From the above analysis, we can see that the light source luminous efficacy and lighting efficiency are completely different, and can not be confused. Chasing the wind of light efficiency from the LED light source to LED lamps and lanterns With the LED luminous efficiency record constantly being refreshed, spreading the LED lamps and lanterns luminous efficiency race there are the following misconceptions. Only mention the luminous efficiency, not to mention the color temperature and color rendering index Should be pointed out how much color temperature CCT and how many colors rendering index Ra under the light efficiency, the same light efficiency, low color temperature than high color temperature is much more difficult. U.S. Energy Star requirements for solid-state lighting indoor luminaires of the relevant color temperature: should be one of the following nominal relevant color temperature (CCT): K, K, K, K, K (commercial only). Energy Star for solid-state lighting indoor lamps: K, K color temperature is not allowed. Only mention the light efficiency, not lighting comfort When the wind of the light efficiency race from the light source to the lamps, the blind pursuit of lighting efficiency of another phenomenon that adds the anti-glare diffuser plate omitted, ignoring the comfort of the lamps, without considering glare control. Only mention the light efficiency, do not talk about reliability To blindly pursue the effectiveness of lamps and lanterns, outdoor lamps and lanterns should be added to the shield omitted, so that the parts should not be exposed, ignoring the reliability of LED lamps and lanterns. LED luminous efficacy and LED lighting performance are different and should not be confused. LED luminous efficacy as a light source indicator may be relatively single, but LED lighting performance is one of the many performance requirements, subject to other performance requirements, the performance indicators should be coordinated, and the not one-sided pursuit of LED lighting performance an indicator, should not be at the expense of lighting environment comfort, reliability, and other indicators as a premise.
#LED light sources and LED lamps and lanterns-03-21This article mainly introduces the principle and application direction of LED in dermatology, by reading this article, you can learn about the application aspects of LED in dermatology. If you require LED chips, please check the stock with PN on Quarktwin's official website. What is the principle of LED application in dermatology? The light therapy LED type is, as the name implies, one that uses a variety of light to achieve skin care results. This type of beauty instrument is relatively speaking, more targeted to various acne, pigmentation, and other skin problems, its various colors of light can reach the deeper layers of different skin, some are the epidermis of the skin, some are penetrating the epidermis to reach the dermis, and even stimulate the mitochondria of the skin cells to promote skin metabolism so that the role of the skin. And different colors of light because of different wavelengths, the effect is also different. Red light: the longest wavelength, can penetrate the skin, into the dermis, the main repair function, and can help the skin to restore vitality and elasticity. Yellow light: the second wavelength, to accelerate the blood circulation of the skin, can play revitalize skin cells, enhance skin vitality, and lighten pigmentation, brightening the effect of dull skin tone. Blue light: the shortest wavelength, better at regulating the skin's oil and water balance, suitable for dealing with acne skin. What are the applications of LED in dermatology medicine? Photorejuvenation Photorejuvenation technology is defined as a non-exfoliative skin rejuvenation treatment using continuous intense pulses of light at low energy density. In just a few years since its introduction in , photorejuvenation technology has rapidly spread nationwide and is widely used in major and medium-sized cities. It has now become one of the main means of improving skin photoaging, and this technology can significantly improve skin wrinkles, rough texture, irregular pigmentation, and enlarged pores, and has been recognized by many technical professionals and cosmetic claimants. The characteristic histological changes of skin photoaging are degeneration of elastic fibers and impaired maturation of collagen fibers in the dermal matrix, which leads to skin laxity and wrinkles. Studies have found that visible to near-infrared LED light penetrates the skin epidermis to reach the skin dermis and, through photothermal and photochemical effects, induces the regeneration and rearrangement of elastic fibers and collagen fibers, thus achieving the effect of reducing skin wrinkles and increasing elasticity. Prevention or treatment of post-inflammatory hyperpigmentation Post-inflammatory skin hyperpigmentation is a common and unavoidable phenomenon in physical and chemical skin aesthetics, especially in the Asian population. For example, to reduce the degree of skin pigmentation after laser treatment, patients are generally advised to avoid seasons with strong ultraviolet rays, avoid sun exposure, and apply sunscreen, but post-inflammatory hyperpigmentation is still difficult to avoid completely. In recent years, a study found that 660nm LED light can prevent and even treat this kind of skin pigmentation after inflammation, which will be a new research hotspot in the field of skin beauty. Promote the healing of wounds Various wavelengths of LED light in the near-infrared can be seen to promote the growth of epithelial cells after trauma and promote the healing of wounds. It also has a good therapeutic effect on the healing of chronic ulcers in the lower limbs of diabetic patients. Reduce inflammation There have been a series of studies showing that LED has an anti-inflammatory effect. It was found that 635nm LED light can inhibit the release of inflammatory mediators, prostacyclin E2 (PGE2), from gingival fibroblasts, thereby reducing the inflammatory response of the gums. If the LED light source is used in advance of pulsed dye laser treatment for skin photoaging, it can reduce the discomfort of skin erythema, swelling, and pain caused by dye lasers. The use of LED light sources before radiation therapy for breast cancer patients can reduce the side effects of radiation therapy. Prevention of scars Keloid scars are a clinically disfiguring and difficult-to-treat skin disorder caused by excessive proliferation of connective tissue after skin injury. Patients often have a keloid complex. They start as small, hard red papules that slowly increase in size, producing round, oval, or irregular keloids that rise above the skin surface and extend outward in a crab foot pattern, with smooth, shiny skin that may be associated with pain and itching. Clinical treatment is difficult and ineffective. Some studies have found that LED can significantly improve the patient's discomfort such as pain and itching and flatten the scar while having the advantage of being non-invasive. Other effects In addition, LED can also be used as a UV-free phototherapy instrument, for photodynamic therapy, treatment of hair loss, reducing skin damage after UV exposure, etc. In short, as a new light source, LED has been gradually applied to dermatology, with the continuous innovation of LED lamps and medical research on the mechanism of the biological effects of LED, LED in dermatology will have unlimited prospects for application. At the same time, LED has high safety and can be used as home medical equipment. The powerful efficacy of LED red and blue light therapy instruments in skin acne treatment LED red and blue light treatment for acne is based on the principle of skin absorption and transformation of specific wavelengths of light, converting the energy of light into cellular energy, accelerating the metabolism of cells in the body, and increasing cellular activity, thus achieving anti-inflammatory and healing effects on the skin. The new generation of LED red and blue light therapy instruments is based on our company's past years of optical instrument production, after repeated improvements. It is mainly reflected in the following aspects. A new generation of LED red and blue light therapy instruments using an imported LED light source, using 635Nm red light, and 460nm blue light, to ensure that the light wavelength single, wavelength error does not exceed plus or minus 10%, so as to ensure that the skin limited absorption of light energy, anti-inflammatory and sterilization go hand in hand, to achieve twice the effect with half the effort. The new generation of LED red and blue light treatment instruments is more convenient to use, using an integrated chip control, a touch screen can complete the red and blue light treatment process of all the controls, in conjunction with the 360-degree rotating arm, can be lifted and rotated together to complete the acne treatment, facial irradiation in one go. Because of the powerful energy of the new generation of LED red and blue light therapy instruments, brings a powerful function and multi-disciplinary use of the scope, out of beauty commonly used to treat acne, skin rejuvenation, whitening, and light spots to reduce pores, but also in the rehabilitation of physical therapy, anorectal, gynecology and other departments to show their skills. A new generation of LED red and blue light therapy instruments red and blue light can be irradiated at the same time, combining the efficacy of two kinds of light, in the removal of acne marks have a particularly good effect and repair role. The photo photodynamic treatment system uses an imported original narrow-spectrum LED light source, which emits a cold light that does not produce high heat and does not burn the skin. It converts light energy into intracellular energy, accelerates the cell growth process cycle, and stimulates fibroblasts to produce collagen. The LED photodynamic beauty treatment system is one of the safest and most effective instruments for treating various skin problems and skin rejuvenation. The clinical application of each light: red light: the wavelength of 635nm red light has the characteristics of high purity, strong light source, and uniform energy density, which is effective in skin care and health care treatment and is called bioactive light. Red light can make cell activity increase, and promote cell metabolism so that the skin secretes a lot of collagen and fiber tissue to fill itself. It accelerates blood circulation, increases skin elasticity, and improves the condition of yellowing and dullness of the skin, thus achieving anti-aging, anti-oxidation, and repair effects that cannot be achieved by traditional skin care. It can also accelerate wound healing and reduce pain. Main effects: whitening and light spot, rejuvenation and wrinkle removal, repairing damaged skin, smoothing fine wrinkles, reducing pores, and increasing collagen. Blue light: Blue light with a wavelength of 460nm has the effect of rapidly suppressing inflammation. In the process of acne formation, it is mainly Propionibacterium that is responsible for the formation of acne, and blue light can efficiently destroy this bacteria without damaging the skin tissue, limiting the formation of acne, and significantly reducing acne in the inflammatory stage to healing within a short period. The treatment with simultaneous irradiation combines the effects of both types of light and is particularly effective and restorative in removing acne scars.
#LED’s applications-03-21This article focuses on common problems with light-emitting diodes, by reading this article, you can learn about the common conditions of light-emitting diodes, so as to better apply light-emitting diodes. If you require LED chips, please check the stock with PN on Quarktwin's official website. Why can not over-voltage or over-current use of white LED? Generally, the most commonly used 5mm white LED, its normal operating voltage is mostly within the range of 3.0-3.5V, the normal operating current of 20mA. but many people mistakenly believe that over-voltage or over-current use of white LED will be brighter, and the actual test results are 15mA after the luminous flux growth is very strong, 20mA after almost no growth, increased to 30mA, only 5% more than 20mA, but LED but there is a significant heat. There is also the life of the test: 20mA work for a month, the attenuation of only 5%, and now there is 95% of the luminous flux, 30mA work to 19 days, the luminous flux is only 50%. It can be considered that a white LED can work under normal conditions for 100,000 hours, used at a high current, with a life of only 600 hours! LED in the general description, are available for more than 50,000 hours, there are some manufacturers claim that their LED can operate about 100,000 hours, but this does not guarantee that LED products can also be used for such a long time. Wrong operation and process can easily "destroy" LED, LED will gradually degrade with time, there are predictions that high-quality LED after 50,000 hours of continuous operation, also maintain an initial light brightness of more than 60%. To extend the life of LEDs, it is necessary to reduce or completely dissipate the heat generated by the LED chip. Heat is the main reason why LEDs stop functioning. Why is the color of the light emitted by white LEDs always a little blue or yellowish? This is due to the white LED, which is originally covered with conversion material phosphor on the 1nGaN base material that emits blue light, and this material will emit yellow light when excited by blue light. So we get a mixture of blue light and yellow light, in the naked eye is white light. Look at the emission spectrum of white LEDs to know that it has two peaks, so no LED emits white light. Such a device is difficult to manufacture because LEDs are characterized by emitting only a single wavelength of monochromatic light, while true white light requires multi-color spectral synthesis. Due to the process, including more than ten imported LEDs, there is also this problem, the spot edge there is off-color, just how much it is. White light-emitting diodes have a slight yellow to slightly purple-white light. Common white light-emitting diodes' color temperature is usually in the range of K to K. LED using a parallel connection method is good or series connection method is good? LED using parallel or series connection method, mainly should be based on the power box circuit form and requirements of the decision. The parallel or series connection method has its advantages and disadvantages. The parallel connection method only requires a lower voltage applied to each LED terminal but requires the use of a ballast resistor or current source to ensure that the brightness of each LED is consistent. If the amount of bias current flowing through each LED is different, their brightness will be different, resulting in uneven brightness across the light source. However, using ballast resistors or current sources to ensure consistent brightness of the LEDs will shorten the battery's life. When the LEDs are connected in parallel, the circuit's total current is the sum of the individual LED currents, so the power supply is required to supply a large enough current. In addition, the circuit uses the series connection method, when one of the LED is broken when the whole string of LEDs are not lit; but when one of the LEDs short circuit when the other LEDs can still light. The circuit uses a parallel connection method, when one of the LED is broken when the other LEDs can still light; but when one of the LEDs short-circuit the entire circuit power will be short-circuited so that not only the other LEDs are not working properly, but also may damage the power supply. Therefore, in comparison or series connection of the circuit is more advantageous. In practice, the series-parallel connection is often used to form an array of LEDs, which can overcome or reduce the single LED break or short circuit caused by the entire string of LEDs that do not light or impact the entire circuit and power supply. The so-called series-parallel connection is to use a small number of LEDs in series and then string ballast resistors to form a branch, and then several branches in parallel to form a "branch group". In addition, can also be used in the form of series and series, that is, in the composition of the "branch group" based on several "branch groups" in series constitutes the entire lamp circuit, this connection not only reduces the impact of a LED failure surface and the ballast resistor Whole into zero, a few high-power resistors into dozens of small power resistors, from centralized installation into decentralized installation, which is conducive to resistive heat dissipation, but also can be more compact lamp design. Can other colors of LED light-emitting diodes be used instead of white LED light-emitting diodes? Absolutely. Only must pay attention, due to the various colors of the LED normal operating voltage is not the same, and the difference is large, such as red and yellow LED normal operating voltage are only about 2V, while the blue and green LED normal operating voltage is closer to the white LED, are about 3V. So in use must be based on the working voltage of various tubes, the number of tubes connected in series or parallel must also be changed accordingly, or change the resistance value of the series current limiting resistor, otherwise, it is possible to make the LED more than the normal working current and shorten its service life, serious and may even burn LED. when using a red or yellow LED, the number of LEDs in a series should be increased, or the series current limiting Resistor should be increased; when using a blue or green LED, generally only adjusting the resistance of the current limiting resistor can be done. What is the reason for the light not lighting when the circuit is installed and powered on? How should I check? This depends on the specific circuit to do specific analysis. But most of the reasons are not tested before the LED is installed or installed in the process of welding accidentally connected to the wrong LED positive and negative polarity, may also be not well soldered caused by false welding (false welding is the surface is welded and not welded solid), false welding is the main reason for the failure, especially the lack of experience in welding novices are most likely to occur in this problem, followed by the soldering iron power too much overheating or welding time is too long and The tube scalded, there may be leakage of the soldering iron caused by LED breakdown short circuit. There is also a part of the driver circuit that is wrongly connected or not well soldered, some circuits may also be the value of the adjusted components not adjusted. When the circuit is installed before power should be carefully checked and verified before powering on, if the light does not light up when the power is on should immediately turn off the power, and then check, you can not knock the circuit board with electricity to try to find the fault, especially the circuit using 220V power supply should be more so. If the circuit is connected to the filter capacitor, the first should also use a screwdriver or wire to short-circuit the two legs of the filter capacitor discharge before checking, this step is very important! Because the filter capacitor residual power supply voltage of more than 1.4 times the high voltage (such as 220V power supply can be as high as 310V), to avoid the residual high voltage on the capacitor injury to the human body or in the circuit on the instantaneous destruction of LED! Check the LED has been installed on the circuit board, you should first recognize the negative mark of the LED body gap, check whether the LED polarity is misconnected, and then use two batteries in series to lead the positive and negative power supply to touch the two feet of each LED, you must pay attention to the battery power polarity to be consistent with the polarity of the LED, to check whether the LED can light. Check the drive circuit, which should be carefully checked according to the circuit diagram circuit is connected to the wrong, pay special attention to checking the rectifier bridge (the long foot is the positive output, its diagonal is the negative output, the other two feet is the AC input) or rectifier diode and voltage regulator diode polarity is correct (printed with a black or white line is the negative end), and check the crystal transistor or voltage regulator integrated circuit of the three electrodes are misconnected. What are the differences between spot LED and diffuse LED? How to choose? Spot LED luminous intensity value is very high, because its light is after its own light aggregation, so its light-emitting angle is generally small, the light irradiation range is small, the light emitted is like a flashlight beam, the brightness of the spot is very high, but the spot periphery is not too high. The LED luminous intensity value of the diffuse type is lower, and its luminous angle is large, up to 120 degrees or more, so it has a large range of light, the light emitted evenly, just like the light emitted by ordinary lighting, although the brightness value of the diffuse type LEDs is generally lower, the total luminous flux (total light) they emit is generally higher than the spot LEDs. Spot LED is most suitable for the requirements of high brightness, but the irradiation range of smaller occasions, such as the production of spotlights, downlights, flashlights, etc., while the diffuse LED is more suitable for general room lighting and the need for soft and uniform light occasions, therefore, to choose according to the specific situation to achieve the best lighting effect.
#LED-03-21This article mainly introduces the LED driver design needs to pay attention to the problems and considerations for choosing an LED driver power supply. By reading this article, you can understand clearly the LED driver power supply and driver design, so as to better apply them. Concerns about LED driver design Chip heat This is mainly for the built-in power modulator high-voltage driver chip. If the chip consumes a current of 2mA, 300V voltage is added to the chip, and the chip power consumption of 0.6W, of course, will cause the chip to heat up. The maximum current to drive the chip comes from driving the power mos tube consumption, a simple formula for I = cf (consider the resistive benefit of charging, the actual I = 2cvf, where c is the cgs capacitance of the power mos tube, v is the gate voltage when the power tube is on, so to reduce the power consumption of the chip, you must find a way to reduce c, v, and f. If c, v, and f can not be changed, then please find a way to divide the power consumption of the chip to devices outside the chip, taking care not to introduce additional power consumption. A little more simple is to consider better heat dissipation. Power tube heat Power tube power consumption is divided into two parts, switching losses and conduction losses. Be aware that on most occasions, especially in LED utility drive applications, switching damage is much greater than the conduction loss. Switching losses and power tube cgd and cgs as well as the chip's driving ability and operating frequency, so to solve the power tube heat can be solved from the following aspects: A, not one-sided according to the size of the on-state resistance to choose MOS power tube, because the smaller the internal resistance, the larger the cgs and cgd capacitance. Such as 1N60 cgs for about 250pF, 2N60 cgs for about 350pF, and 5N60 cgs for about pF, the difference is too great, and the choice of power tubes, enough is enough. B, the rest is the frequency and chip driving ability, here only talk about the impact of frequency. Frequency and conduction loss are also proportional to the power tube heat, so the first thing to think about is not a little high-frequency selection. Find ways to reduce the frequency! However, note that when the frequency is reduced, to get the same load capacity, the peak current is bound to become larger or the inductor also becomes larger, which may lead to inductors into the saturation region. If the inductor saturation current is large enough, you can consider changing the CCM (continuous current mode) to DCM (discontinuous current mode), which will require an additional load capacitor. Operating frequency derating This is also a relatively common phenomenon in the debugging process of the user, frequency reduction is mainly caused by two aspects. The ratio of input voltage and load voltage is small, and the system interference is large. For the former, pay attention not to set the load voltage too high, although the load voltage is high, the efficiency will be higher. For the latter, you can try the following aspects: a minimum current set again small; b, wiring clean point, especially since this critical path; c, the inductor selection of small points or choosing closed magnetic circuit inductor; d, adding RC low-pass filtering it, the impact is a bit bad, C consistency is not good, the deviation is a bit large, but for lighting should be enough. In any case, there is no benefit of frequency reduction, only the bad, so it must be solved. The choice of inductor or transformer Many users respond to the same drive circuit, with a production of inductors with no problem, with b production of inductors current has become smaller. Encounter this situation, to look at the inductor's current waveform. Some engineers do not notice this phenomenon and directly adjust the sense resistance or operating frequency to reach the required current, which may seriously affect the service life of the LED. So, before the design, a reasonable calculation is necessary, if the theoretical calculation of the parameters and debugging parameters are a little far, to consider whether the frequency reduction and transformer saturation. When the transformer is saturated, L will become smaller, resulting in a sharp increase in the peak current increment caused by transmission delay, then the peak current of the LED also follows. In the premise of the average current remains unchanged, you can only watch the light decay. LED current size We all know that the LED ripple is too large, LED life will be affected, and how big the impact is, and have not seen what experts said. Previously asked the LED factory for this data, they said within 30% is acceptable, but then did not go through the verification. It is recommended to try to control the smallest possible. If the thermal solution is not good, LED must be used to reduce the amount. Also hope that an expert can give a specific indicator, or affect the promotion of LED. If you require LED driver chips, please check the stock with PN on Quarktwin's official website. What need to pay attention to when buying a drive power supply? One: is to recognize the brand of capacitors, of which Rubycom (Rubycom Japan) is particularly well-known, and Heng Ying (HY domestic) is more common, of course, the price is more expensive than other uncomfortable brand of capacitors by a few cents. Second: whether with an IC control chip, because the IC control chip has a stop short circuit, overvoltage, overload, over temperature, and other protection functions. As long as these two points are in place of the drive power supply, the quality has been very good. What do you need to consider when choosing a LED driver power supply? High reliability LED products are mainly LED chips and power supplies, heat dissipation housing, control circuits, and other components. Among them, the LED power supply directly affects the good or bad of the product. Especially LED street light products, due to installation at the high altitude, maintenance is not convenient, and the cost of maintenance is also large. High efficiency LED is an energy-saving product, the drive power supply must also meet the requirements of energy saving. In particular, the power supply is installed in the structure of the lamp, especially important. Because the LED luminous efficiency decreases as the temperature of the LED rises. High efficiency of the power supply, its power dissipation is small, the heat generated in the lamps and lanterns is small, also reduces the temperature rise of the lamps and lanterns. Slowing down the LED light decay is beneficial. Constant current drive mode To match the voltammetric characteristics of the LED, the LED power supply must be used in a constant-current drive mode. Surge protection LED impact resistance is relatively poor, so to strengthen the protection of this aspect. Especially for some products installed outdoors, the grid load starts and stops and lightning strikes will have an impact on the power supply. Therefore, the input side of the LED driver power supply has a surge suppression protection circuit, to avoid instantaneous damage to the LED switch. Temperature protection function Power supply In addition to the conventional protection function, it is best to increase the LED chip temperature negative feedback in the constant current output to prevent the LED chip PN junction temperature is too high. LED power supply life To improve the life of the LED driver power supply, you need to improve many aspects: the use of higher life capacitors, improving the efficiency of the power supply, doing a good job of power supply heat dissipation function, and optimizing the thermal design of the lamps. The LED power supply is a switching power supply, the quality and reliability of the switching power supply depend on its circuit design, production process, and the quality of the device. An electrolytic capacitor is an essential component of a high-power switching power supply. The normal working life of the switching power supply depends on the life of the electrolytic capacitor used in the power supply, and the life of the electrolytic capacitor depends on the life of the capacitor itself and the working temperature, and the working life of the electrolytic capacitor varies greatly under different temperatures.
#LED driver design-03-21This article mainly introduces the definition and the working principle of bi-color light-emitting diodes, through reading this article, you can learn the advantages and disadvantages of light-emitting diodes, as well as the classification and working principle of bi-color light-emitting diodes, so as to better apply bi-color light-emitting diodes. If you want to learn more about LED, check out the other articles in the LED list on Quarktwin's official website. What are the advantages of LED? 1. Short response time (in ns), can reach a very high flashing frequency. 2. Long service life and not affected by continuous flashing. 3. 100,000 hours of life can be achieved in a safe operating environment, and even at high temperatures above 50 degrees, the service life is still about 40,000 hours. 4. Shock resistance and other mechanical shock, because it is a solid-state component, with no filament, glass cover, etc., compared to fluorescent lamps, incandescent lamps, etc., can withstand greater shock. 5. Small size, its volume can be made very small (less than 2mm). 6. Easy to focus, because the light-emitting volume is small and easy to achieve the required degree of dispersion using lenses, etc. By changing the shape of its package, its light-emitting angle from large angle scattering to fine angle focus can be achieved. 7. Monochromatic, because it is a single energy level photon, the wavelength is relatively single and can provide a variety of simple colors without adding a filter. 8. Color gamut is slightly wider, some white light-emitting diodes cover a wider color gamut than other white light sources. What are the disadvantages of an LED? 1. Heat dissipation problems, LED in the process of electroluminescence another part of the energy into heat, such as the inability to timely dissipate out, the junction temperature of the PN junction will rise, accelerating the aging of the chip and packaging resin, so that the chip failure, affecting the service life of LED and luminous performance. 2. Poor waterproof performance, is a fatal weakness of the outdoor use of the light source internal oxidation of internal metal after absorbing water affects the output or produces internal stress, phosphor moisture discoloration, and light color drift. 3. Higher cost. Light source. Heat sink. Power supply. High-transmission lampshade/lens/reflector. The cost of the four collectively pushes up the cost of LED. 4. Need a driver to provide constant current power, driver life is an important factor affecting the life of the lamp. 5. Semiconductor devices, sensitive to the effects of static electricity, easily to the electrostatic breakdown of the PN junction resulting in leakage current or dead lights. What is a dual-color LED? A bicolor LED is a type of LED light that emits two different colors of light. It is usually a bi-color LED, which means it has two separate LED chips in the same package, each of which emits a different color. A dual-color light-emitting diode is set up in a package structure of two different single-color light-emitting diodes, where the first light-emitting diode positive electrode and the second light-emitting diode negative electrode interconnected by a lead pin outward; the first light-emitting diode negative electrode by another lead pin outward, the second light-emitting diode positive electrode by the third lead pin outward; or the first light-emitting diode's negative electrode and the second light-emitting diode's positive electrode interconnected by another pin outward. What is the classification of dual-color LED? 1. Three feet bi-color LED. this light has three feet, the middle foot is common, and the two sides of the foot are a straight foot, and a diagonal foot, respectively, corresponding to a color. To give an example of the red and green two-color common sun. General straight foot corresponds to the red, diagonal foot corresponds to green, when the current flows from the middle foot to the square foot, the red light works; when the current flows from the middle foot to the diagonal foot, the green light works; when the current flows from the middle foot to the square foot and diagonal foot at the same time, the red light and green light work at the same time, mixed into the color. The general circuit will choose this two-color LED red and green to indicate the circuit's two working states. A special point will also be to the third mixed color, but the consistency of this mixed color is more difficult to grasp. 2. Four-legged dual-color. In this two-color LED the left two pins and the right two pins constitute two circuits, respectively, to drive two colors to indicate the working state of the two circuits. 3. Two legs of two-color. This two-color LED is also called a bi-directional LED. this two-color LED is a very clever use of light-emitting diode voltammetric properties. To give an example of red and green bi-directional LEDs. This light has only two feet, a long foot, and a short foot. Red LED's P pole, that is, the positive pole and the long foot welding, N pole, that is, the negative pole and the short foot welding; green LED's P pole and the short foot welding, N pole and the long foot welding; when the current flow from the long foot to the short foot, the red light works normally, the green light because the reverse does not conduct and does not work; when the current flows from the short foot to the long foot, the green light works normally, the red light does not work, to control the current flow to control the red and green two colors. What is the shape and symbol for a two-color LED? Two-color light-emitting diodes can emit a variety of colors of light. Two-color light-emitting diode has two pins and three pins, often MAXAMEE see the physical shape of the two-color light-emitting diode shown in Figure 8-5 (a), Figure 8-5 (b) for the two-color light-emitting diode circuit symbols. What is the working principle of dual-color LED? Two-color light-emitting diodes are two colors of light-emitting diode production package together, the common red and green two-color light-emitting diodes. Two-color light-emitting diodes inside the two diodes are connected in two ways: one is a common positive or common cathode form (that is, the positive or negative terminal connected into a common terminal), the second is the positive and negative connection form (that is, a diode positive and another diode negative connection). The common positive or common cathode bi-color diode has three pins, and the positive-negative connection bi-color diode has two pins. The following circuit is shown in Figure s-6 illustrates the working principle of bi-color light-emitting diodes. The figure for the three pins of the two-color light-emitting diode application circuit. When the switch is closed s1, there is current flow through the green tube inside the two-color light-emitting diode, two-color light-emitting diode emits green light when the switch is closed m, the current through the internal red tube, the two-color light-emitting diode emits red light, if both switches are closed, red and green tubes are on, the two-color diode emits a mixed color light yellow light. Figure 8-6 (b) for two pins of the two-color light-emitting diode application circuit. When the switch is closed s1, there is current flow through the red tube, and the two-color light-emitting diode emits red light; when the switch is closed s2, current through the internal green tube, the two-color light-emitting diode emits green light; when the switch is closed S3, due to periodic changes in the polarity of the AC power supply, it produces alternating current flow through the red and green tubes, red and green tubes are bright, and two-color that emits light in red and green mixed color yellow.
#Bi-color LEDCOB technology is increasingly becoming a cornerstone of modern LED lighting solutions due to its superior performance characteristics. Its capacity to produce high-lumen output while using minimal energy makes it an appealing choice for various applications, including residential, commercial, industrial, and outdoor lighting.
The uniform light distribution achieved by COB LEDs is particularly valued in settings that demand consistent and high-quality illumination. Furthermore, the reduction in glare and the seamless light output make COB LEDs preferable in environments where visual comfort is paramount. COB technology is increasingly becoming the industry’s preferred solution with the rising demand for energy-efficient and high-performance lighting.
Discover COB LED technology, its advantages and disadvantages, diverse applications, and how it’s transforming the lighting industry with exceptional performance and energy efficiency.
COB (Chip on Board) LED isn’t just another tech term—it’s redefining how we approach lighting. Imagine numerous tiny LED chips packed closely together on a single board. The result? A light source that’s brilliantly bright, highly efficient, and effective. But what truly makes COB LED a revolutionary force in lighting?
One of the critical benefits of COB LED is its compact size combined with high power output. The concept involves integrating multiple powerful LED chips onto a single board, creating a more intense light source that occupies less space.
This innovation allows manufacturers to produce more powerful lighting solutions in smaller, more versatile designs, making them ideal for space-constrained applications like compact fixtures or portable lights.
In the sections below, we explore the details of COB LED technology, its applications, and its pros and cons.
Chip-on-board (COB) technology represents a significant advancement in LED lighting. In this design, multiple LED chips are directly mounted onto a single substrate, typically made of aluminum, ceramic, or a flexible PCB (Printed Circuit Board). This design creates a single, dense, and highly efficient light-emitting module.
Unlike traditional LED packages, where each LED chip is individually packaged, COB technology integrates multiple chips without separate encapsulation. These chips are connected to the substrate, and a layer of phosphor coating is often applied to convert the emitted blue light into shades of white or other colors tailored to the specific application.
The result is a powerful and uniform light source that offers superior brightness, energy efficiency, and light quality performance. COB LEDs are known for their ability to provide high-lumen output in a compact design, making them perfect for applications that demand powerful illumination in confined spaces. The absence of separate chip packaging allows for better thermal management. The heat generated by the LEDs is more effectively dissipated through the substrate, enhancing the overall longevity and reliability of the lighting solution.
Pros of COB LEDs
COB LEDs are designed to deliver a high-lumen output, producing substantial light relative to their size. This high-intensity illumination is achieved by integrating multiple LED chips on a single substrate, allowing COB LEDs to generate more light than traditional LED configurations. This makes COB LEDs ideal for applications requiring powerful lighting in compact fixtures, such as spotlights, floodlights, and downlights. The ability to produce intense light ensures excellent visibility and brightness, even in large spaces.
Integrating multiple LED chips into a single module results in a compact design that occupies less space than traditional LED setups with individual chip packaging. This compactness allows for innovative and space-saving designs in lighting fixtures. It enables the creation of sleek and modern fixtures that can be used in tight spaces without sacrificing light output.
COB LEDs produce a continuous and even light source without additional optics or diffusers. The proximity of the LED chips on the substrate results in a smooth and uniform light distribution. This uniformity reduces shadows and hotspots, providing consistent lighting quality. It is particularly beneficial in settings where uniform illumination is critical, such as workspaces, retail environments, and public areas.
The design of COB LEDs facilitates better thermal management due to the direct mounting of LED chips onto the substrate. The heat produced by the LEDs is effectively dispersed through the substrate material. Enhanced heat dissipation contributes to the lighting fixture’s longer lifespan and reliability. It also helps maintain optimal performance and prevents overheating, which can negatively impact LED performance and longevity.
These lights have a higher CRI (Color Rendering Index), producing light that resembles natural sunlight. This improves color accuracy and vibrancy, making them ideal for accurately showcasing products and artwork in museums, galleries, and retail environments.
COB LEDs are highly energy-efficient, converting significant electrical energy into light rather than heat. This efficiency results in lower energy consumption compared to traditional lighting technologies. Lower energy consumption reduces operating costs and contributes to overall energy savings. Additionally, the energy efficiency of COB LEDs supports environmental sustainability by reducing overall energy usage and carbon footprint.
The advanced features of COB LEDs make them suitable for various applications. They can be used in multiple lighting scenarios, from residential to commercial and industrial settings. This versatility allows for implementing COB LEDs in diverse environments, including residential lighting, retail displays, office illumination, outdoor lighting, and more.
Cons of COB LEDs
COB LEDs generally cost more upfront than traditional lighting solutions or other LED technologies. The initial investment may be a barrier for some users, particularly those with tight budgets. However, this cost is often offset over time by the energy savings and longer lifespan of COB LEDs.
Due to their integrated design and compact form, COB LEDs may require more specialized installation procedures than standard LED lights. This complexity may necessitate professional installation, adding to the overall cost. Additionally, compatibility with existing fixtures and dimming systems may need to be considered.
COB LEDs can sometimes produce intense light that may cause glare, mainly when used in high-lumen applications or poorly shielded fixtures. Glare can affect visual comfort and cause eye strain, particularly in environments where direct light exposure is unavoidable. Proper fixture design and the use of diffusers can help mitigate this issue.
The beam angle of COB LEDs can be more limited than that of some other LED technologies. This limitation may require additional optics or reflectors to achieve the desired light distribution. In some applications, achieving the correct beam angle may involve extra design considerations and adjustments.
Although COB LEDs have improved heat dissipation compared to older technologies, their high power output can still generate significant heat. Effective heat management is crucial to maintaining performance and longevity. Inadequate heat dissipation can impact the efficiency and lifespan of the LEDs, requiring careful consideration of fixture design and ventilation.
COB LEDs may have compatibility issues with existing dimming systems, controls, or fixtures. Ensuring compatibility with current lighting systems or retrofit scenarios may require additional components or modifications. This can add to the complexity and cost of upgrading COB LED technology.
If you are looking for more details, kindly visit LED Encapsulation Materials for General Lighting.
Surface Mounted Device (SMD) LEDs are another popular LED technology commonly used in various lighting applications. In SMD technology, each LED chip is individually mounted onto a circuit board and encapsulated in a small package. SMD LEDs are versatile and are often used in applications such as strip lighting, panel lights, and other general-purpose lighting solutions.
The critical difference between COB and SMD LEDs is their design and light output. COB LEDs feature multiple LED chips grouped on a single substrate, creating a single light-emitting module. This design allows COB LEDs to produce a more concentrated and uniform light output than SMD LEDs, which typically emit light from individual points. As a result, COB LEDs are often preferred in applications where consistent and high-intensity lighting is required, such as led downlights, led spotlights, and outdoor floodlights.
COB LEDs generally offer better thermal management due to their integrated design, where heat is more efficiently dispersed across the substrate. This advantage makes COB LEDs more durable and reliable in high-power applications. On the other hand, SMD LEDs are known for their flexibility and ease of use, making them suitable for applications where a broader and more dispersed light output is needed.
Dual-in-line package (DIP) LEDs are an older technology that was widely used before SMD and COB LEDs. DIP LEDs consist of a single LED chip encased in a cylindrical epoxy package with two parallel connecting pins (hence the term “dual in-line”). These LEDs were commonly used in early electronic displays, indicator lights, and basic lighting applications.
The differences between COB LEDs and DIP LEDs are stark. COB LEDs represent a much more advanced and efficient technology, offering significantly higher light output, better energy efficiency, and superior light quality. DIP LEDs are limited in brightness and unsuitable for modern lighting applications requiring high-lumen output and consistent light distribution.
Furthermore, COB LEDs are far more compact, allowing greater flexibility in lighting fixture design and application. With their bulkier packaging and lower efficiency, DIP LEDs have largely been phased out in favor of more modern LED technologies like COB and SMD. Today, COB LEDs are preferred for their ability to deliver robust and uniform illumination, making them appropriate for diverse uses, such as in residential, commercial, industrial, and outdoor lighting environments.
Chip on Board (COB) technology is a sophisticated process that begins with selecting and preparing the LED chips. Manufacturing COB LEDs involves the precise arrangement of multiple LED chips directly onto a substrate. This substrate usually comprises aluminum, ceramic, or a flexible printed circuit board (PCB), selected for its superior thermal conductivity and electrical insulation properties. The substrate is the base on which the LED chips are mounted, forming a compact and integrated light source.
The process starts with applying a thin adhesive layer on the substrate, which secures the LED chips. The chips are then carefully positioned near each other, often with no space in between, allowing for maximum density and light output. Once the chips are aligned and fixed, wire bonding is used to establish electrical connections between the chips and the circuitry on the substrate. This step ensures the chips can operate as a unified module.
Next, the entire assembly undergoes encapsulation. In this stage, a layer of protective material, often silicone or epoxy resin, is applied over the chips. This encapsulation protects the delicate LED chips from physical damage and environmental factors and helps improve the optical performance of the COB module. It enhances the light extraction efficiency by directing the light from the chips outward, reducing internal reflections and losses.
The final step in the COB manufacturing process involves applying a phosphor coating, which is crucial for determining the color of the light emitted by the COB LED. The phosphor coating is applied uniformly over the encapsulated LED chips and converts the blue light emitted by the chips into white or other desired colors. The type and thickness of the phosphor coating can be adjusted to achieve specific color temperatures and rendering characteristics.
COB technology distinguishes itself by integrating multiple LED chips into a single module, creating a highly efficient and powerful light source. Unlike traditional LED designs, where individual chips are separately packaged, COB LEDs combine these chips on one substrate, functioning as a cohesive unit.
The LED chips are densely packed, often side by side, without encapsulation. This arrangement maximizes the luminous efficacy by allowing all the chips’ combined light output to be concentrated into a single, intense beam. The close packing of the chips also eliminates the need for additional optical components like lenses or reflectors, which are typically required in other LED configurations to direct and shape the light.
This packing method enhances the light output and simplifies the overall design of the lighting fixture. By reducing the required components, COB LEDs achieve a more streamlined and compact form factor, making them ideal for applications where space is limited and high light output is essential.
The design of COB LEDs is centered around the efficient arrangement of LED chips and the application of a phosphor coating, which play critical roles in the light source’s performance and versatility.
The chips in a COB module are strategically placed in a grid or matrix pattern on the substrate. This arrangement is carefully engineered to ensure uniform light distribution throughout the module. By placing the chips close together, COB LEDs can produce a seamless and consistent light output with minimal dark spots or shadows. This design is especially beneficial for applications that demand uniform and diffuse illumination, such as commercial, architectural, and display lighting.
The chip arrangement also facilitates better thermal management. Since the chips are mounted directly on the substrate, heat generated during operation is efficiently conducted away from the chips and dispersed across the substrate. This efficient heat dissipation helps in maintaining the longevity and stability of the COB LED, even in high-power applications.
The phosphor coating is a vital component in COB LED design, as it determines the color characteristics of the emitted light. The coating is applied over the entire array of LED chips, converting the blue light emitted by the chips into the desired color of light, typically white.
The phosphor coating can be fine-tuned to produce different color temperatures, ranging from warm white (around K) to cool white (K). Adjusting the phosphor layer allows manufacturers to tailor COB LEDs for specific applications, such as retail environments where accurate color rendering is critical or in residential settings where warm, inviting light is preferred.
Additionally, the uniform application of the phosphor coating ensures that the light output is consistent across the entire COB module. This uniformity is essential for achieving high-quality, glare-free lighting that enhances visual comfort and aesthetic appeal in various environments.
Understanding the unique advantages of COB (Chip on Board) LEDs can help make an informed decision when selecting the appropriate LED technology for various lighting applications. Here’s an in-depth look at why COB LEDs stand out compared to other technologies, particularly for commercial, outdoor, and residential lighting.
1. Superior Light Quality and Uniformity
COB LEDs are renowned for delivering exceptionally uniform light with minimal glare and hot spots. Their design integrates multiple LED chips onto a single substrate, allowing them to produce a smooth, consistent beam of light. This uniformity is particularly beneficial in commercial settings, where lighting quality can significantly impact the ambiance and functionality of spaces such as retail stores, offices, and hospitality venues.
In outdoor applications, the even light distribution of COB LEDs enhances visibility and safety while minimizing light pollution. For residential use, COB LEDs provide a pleasing, natural light that improves the aesthetic of living spaces and creates a comfortable environment.
2. High Luminous Efficiency
One of the standout features of COB technology is its high luminous efficiency. COB LEDs can deliver high-lumen output while retaining a compact design, making them perfect for applications where space is limited but powerful lighting is essential. This efficiency in commercial environments translates to brighter spaces with fewer fixtures, reducing installation and energy costs.
For outdoor lighting, such as streetlights, floodlights, and landscape lighting, COB LEDs can cover large areas with fewer light sources, contributing to lower energy consumption and longer-lasting installations. In residential settings, the energy efficiency of COB LEDs helps homeowners save on electricity bills while enjoying bright, adequate lighting.
3. Enhanced Durability and Longevity
COB LEDs are designed with excellent thermal management, crucial for maintaining performance and longevity. The substrate materials used in COB technology, such as aluminum or ceramic, provide superior heat dissipation, reducing the risk of overheating and extending the lifespan of the LEDs.
This durability is especially advantageous in outdoor lighting applications, where fixtures are exposed to harsh environmental conditions, including temperature fluctuations, moisture, and dust. In commercial settings, the long lifespan of COB LEDs reduces maintenance costs and downtime, making them a cost-effective solution in the long term. Residential users also benefit from the low maintenance requirements and long-lasting performance of COB LEDs.
4. Cost-Effectiveness in the Long Run
While COB LEDs may have a higher upfront cost than other LED technologies, their energy efficiency and durability provide substantial cost savings over time. In commercial and industrial applications, where lighting systems run for extended periods, the reduced energy consumption of COB LEDs leads to significant savings on utility bills.
Combining energy efficiency and low maintenance for outdoor lighting makes COB LEDs a financially sound investment, especially considering the costs associated with frequent replacements or repairs of traditional lighting systems. Homeowners can enjoy immediate and long-term savings in residential applications by choosing COB LEDs for their lighting needs.
5. Versatility Across Applications
COB LEDs are versatile and can be customized to suit various lighting applications. Whether creating a warm, inviting atmosphere in a living room, providing high-intensity task lighting in a workshop, or illuminating outdoor spaces with powerful, focused beams, COB LEDs offer the flexibility to meet diverse lighting requirements.
In commercial lighting, COB LEDs are ideal for retail displays, highlighting products with accurate color rendering and vibrant light. In outdoor settings, they are used in streetlights, floodlights, and landscape lighting, where their ability to produce powerful, directional light enhances safety and visibility. For residential use, COB LEDs can be incorporated into various fixtures, from recessed downlights to track lighting, allowing homeowners to customize their lighting according to their preferences.
Are you interested in learning more about Heat-seal Adhesives for Peel-off Ends? Contact us today to secure an expert consultation!