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A Brief History Of Green Lighting Series - Semiconductor Lighting

Sep 27, 2019

   China low carbon net attention

   Semiconductor lighting is a revolutionary new generation of lighting, compared with the previous traditional lighting has a lot of advantages, but there are also disadvantages.Should use historical and dialectical point of view, vertical and horizontal comprehensive view of the analysis, to better understand LED, let LED lighting better development.

   Semiconductor lighting can be divided into LED lighting, OLED lighting and LED laser lighting.At present, the dominant light is blue chip white LED lighting,OLED lighting also has some products in many exhibitions and exchanges, and LED laser lighting in automotive lighting began to show its technical advantages.Here mainly involves the LED lighting technology and related content.

Principle and characteristics of LED lighting technology

   Milestone as lighting the third and fourth generation of white LED light source of blue chip type, its luminous principle is majority carrier of p-type semiconductor "holes" and the majority carrier in the n-type semiconductor "electronic", under the action of applied electric field electronic across the p-n junction between barrier into the p-n junction area and other areas, in the process of the "hole" and "electronic" composite, releasing energy are blue, blue light emergent chip after absorbed by encapsulating layer phosphor and phosphor conversion red and green light, red and green light from fluorescent powder packaging layer transmission out of blue, red, green and blue sanki colours mixed at various points in the space to make white light.

   LED light source belongs to solid state semiconductor electronic luminescence, which belongs to a special nonlinear positive resistance, which makes it under the rated operating point without the need for current stabilizer can be lit up and normal operation.However, when it overloads above the rated working point, the positive resistance becomes smaller and smaller, and tends to zero resistance. The voltage and current relationship changes dramatically, leading to a small voltage fluctuation of the power supply, which will increase the current. Therefore, the driving power is required to limit and stabilize the working current.Is one of the most important indicators of LED lighting, lighting the first few Lm/W, from the 1990 s to 2015 in 303 Lm/W, the electro-optic conversion efficiency is as high as 44.5%, that means 44.5% of the electricity can be converted into visible light, it is 30 times that of conventional incandescent lamp, is 4.5 times that of ordinary conventional fluorescent lamp is about high-grade rare earth fluorescent lamp and 3 times of high pressure sodium lamp and metal halide lamp, its energy saving effect is very significant.

   In addition, as LED is an electronic device, its normal service life is very long, with the general high-power LED service life of 50,000 hours, and the low-power LED service life of even as long as 80-100,000 hours.Low voltage LED to its combination is convenient, but with the electronic drive circuit, control circuit complete fusion, compared with the traditional class of gas discharge light source control device, the principle makes driving circuit structure optimization, greatly has been greatly improve the reliability and life expectancy, intelligent control circuit and extremely convenient, really opened up a new era of revolutionary and intelligent illumination.

   Without leds there would be no real development in intelligent lighting and visible light communication.In addition, the spectrum of LED, despite its blue peak, covers the entire visible spectrum and is much more continuous and smooth than that of conventional lighting, such as tri-primary fluorescent lamps and energy-saving lamps.However,LED voltage suppression has both advantages and disadvantages.

   First of all, voltage depression, can be combined into a variety of voltage and current application forms, so that the terminal product specifications variety, leading to mass production more difficult to increase the production cost, and make standardization, standardization difficulty.

Secondly, the mainstream LED has inherent defects of uneven luminosity and chroma spatial distribution, which makes it more difficult to improve the light quality.

Thirdly, the advantages of the display technology with small luminous points and high brightness of LED have become the prominent disadvantages of dazzling, glare and even photobiosafety in lighting.