China and Japan LED lighting situation compared to China's promotion efforts

LED is the abbreviation of LightEmittingDiode (light emitting diode). The light emitting diode is a new solid-state cold light source, the most significant feature of LED is of long service life, high photoelectric conversion efficiency, good seismic performance, easy to use, is being used more and more widely in the lighting system. Under the same illumination, the power consumption and life of LED lamp have obvious advantages compared with incandescent lamp and fluorescent lamp.

Development all white light-emitting method, as well as the development of a new generation of fluorescent powder, has made the LED luminous efficiency is greatly improved, the current industrial products has increased from 45lm/w to 100lm/w (2009, cool white light effect of Cree company has more than 100lm/W, in the 350mA and the warm white light is more than 75lm/W) study on the level of 160lm/w, the highest level, the target expected more than 200lm/w. Life 40 thousand hours to 80 thousand hours.

China has rich non-ferrous metal resources, gallium and indium rich reserves, accounting for 70%-80% of the world's reserves, which makes China's development of semiconductor lighting industry has resource advantage. By 2010, the total output value of China's LED industry will be more than 150 billion yuan. Japan as early as in 2002 to spend 5 billion yen to implement white light, the entire budget for the budget of 6 billion yen.

On May 7, 2010 -12, Henan Province Association of lighting lighting experts and entrepreneurs in Japan for a review of Japanese lighting, LED lighting in Japan is not satisfactory.

Luminescence mechanism, LED light source

Totally different light-emitting principle with incandescent lamp or gas discharge lamp. Spontaneous emission of LED is due to the recombination of electrons and holes.

LED N P N type semiconductor layer is formed and layer formed by P type semiconductor, and active by double heterostructure into the middle layer. The active layer is light emitting area, using the external power electron injection to the PN junction, the positive bias under the action of electronic N area will spread to the positive direction, into the active layer, the P area of the hole will spread to the negative direction, into the active layer, the recombination of electrons and holes, produce spontaneous radiation, see figure 1. LED is different because of their use of the material, the diode and the electrons and holes for energy levels are different, the combination of photon energy and different wavelengths of light can affect the level of order, it is the light of different colors, such as red, orange, yellow, green, blue or visible light.

, two white LED

There white LED provides a white LED semiconductor lighting for indoor and outdoor lighting engineering more and more. White LED light efficiency has made great progress, white LED has even begun to challenge the status of traditional light sources.

At white LED there are two main ways: the first one is to get through the white phosphor; the second one is the LED chip package of different colors together, multi chip mixed white light. According to the above two methods, according to the number of the primary color light source, the system can be divided into two primary colors and multi color system.

Phosphor for white LED

(1) two phosphor converted white LED

Two color white LED is a blue LED chip and YAG fluorescent powder made of. Blu ray chip is commonly used InGaN chip, in addition to the use of AlInGaN chips. The advantages of blue chip LED with YAG fluorescent powder method has the advantages of simple structure, low cost, relatively simple fabrication process, but the method also has some disadvantages, such as the blue LED efficiency is not high enough, resulting in low efficiency of white LED phosphor itself; energy loss; phosphor and packaging materials with the time of aging, resulting in color drift and life shortening.

(2) three color phosphor LED

Three color phosphor LED in high luminous efficiency can effectively enhance the premise of color LED. Three primary colors

The most common way to LED is LED by UV excitation of three phosphor group may be the effective excitation of the ultraviolet radiation.

Compared with blue LED+YAG phosphor for white light, using the method of UV LED+ three color phosphor to more easily get the color white, this is because the LED color is only decided by the ratio of fluorescent powder. In addition, this type of white LED with high color rendering, color and color temperature can be adjusted, the use of high conversion efficiency of phosphor can improve the light efficiency of LED.

But UV LED+ three color phosphor has some defects, such as low conversion phosphor in the ultraviolet radiation aging rate; the powder is difficult; packaging material easy to aging under UV irradiation, short service life.