LED light engine definition and technical difficulties

LED light engine refers to the overall combination of LED package (assembly) or LED array, LED driver, and other brightness, thermal, mechanical and electrical components. The device is directly connected to the branch circuit through a conventional connector that matches the LED lamp. The LED lamp is designed not to use a standard lamp holder.

　　LED light engine popular definition

　　Professor Mao Yuhai summarized a more popular definition of LED light engine, that is, the constant current driver of LED light source is installed on an aluminum substrate.

　　Can the entire LED lamp also be called a light engine? Mao Yuhai pointed out that of course not. Just like the entire car cannot be called an engine, the engine is the powertrain of the car, but it is not equal to the car. It also needs a shell to become a car. The reason why there is a need for products such as light engines is that all lamps have a variety of appearances. Some lamps can even be called works of art.

　　Take the incandescent lamp for example. It can be said that it only has the simplest form of light bulb, and at most it can be combined with candle lamps or very small Christmas lights. But its appearance can be varied. In particular, crystal lamps are all kinds of arts and crafts, extremely gorgeous. However, LEDs must also be equipped with extremely complex constant current drive sources to work like an incandescent lamp (it can light up when connected to 220V). If LEDs are made into light engines, they can also light up when connected to 220V like incandescent lamps (of course, a matching heat sink is also required ). This will help standardization on the one hand, and on the other hand, it will greatly facilitate the designers of the shell (and heat sink) to give full play to their abilities.

　　Interpretation of LED light engine technology difficulties

　　The first difficulty is that there is not enough space.

　　Take the bulb as an example: if an ordinary switch constant current source is placed on the LED aluminum substrate, there are more than 30 components, including large inductors, transformers and large capacitors. The components will block the light, and the more components there are, the worse the reliability. Therefore, the switch constant current source cannot be used.

　　In this case, a linear constant current power supply can be used to solve the problem.

　　But at the same time, Mao Yuhai said that using ordinary linear constant current source is not a feasible light engine solution. Although it solves the problem of occupying space, the linear current source is inefficient, especially when the mains power is high, and it generates a lot of heat.

　　Although no matter where the power supply is placed, its heat will always be dissipated into the space through the radiator, but when the power supply and the light board are placed together, the power consumed by the power supply will become heat and be directly added to the light board, which will increase the heat that the light board needs to dissipate, which will increase the junction temperature of the LED and reduce its lifespan.

　　The second difficulty is heat dissipation

　　Take a 10-watt LED bulb as an example. Assuming the power efficiency is 85%, that is, the driving power of the LED is 8.5 watts, and the power consumption of the power supply itself is 1.5 watts. Assuming the LED luminous efficiency is 30%, that is, 70% of the power is converted into heat and needs to be dissipated. Now add the 1.5w of the power supply, it becomes 7.8W of power, which will increase the heat by 19.2. Integrating this power supply into an aluminum substrate will increase the junction temperature of the LED by 15.8%. Assuming the original junction temperature of the LED is 85℃, the junction temperature of the LED will now increase to 98.4℃, which will reduce the life of the LED.

　　In this case, only a very efficient linear constant current source can realize the light engine, which has the advantages of high efficiency and smooth light effect. High efficiency drive reduces overall heat generation.

　　Yan Chongguang, adjunct professor at the Shanghai Institute of Microelectronics of Peking University and an expert in LED lighting technology, said that the use of light engines has improved the overall performance of LED lamps and greatly accelerated the promotion of LED lamps.

　　The light engine products of Efilai Optoelectronics have a comprehensive light efficiency index that exceeds that of similar foreign products by 30% at the same cost, making it the first Chinese company to break the dominance of foreign companies in the field of high-end LED lighting.