Abstract
In recent years, LED technology has achieved impressive improvement. With many advantages such as high efficiency, long life, variable colors and low consumption, LED has played an important role in many application areas. High- power white LEDs are the key devices for semiconductor illumination. The improvement of the luminous efficacy and reliability of high-power white LEDs is critical for their applications in general lighting. Studies on the LED reliability are the basis of the improvement of the LED reliability. In this paper，we introduce the method and development of the reliability of LED in the home and abroad research and review the degradation mechanism that limit the reliability of LEDs，and put forward some ideas about the reliability of the high-power LED lamps.
Key words: high-power white LED; applications; reliability
Introduction
Semiconductor illumination is one of the most promising high technology fields in 21st century. Since the 1990s, with the rise of the third generation of semiconductor which is represented by GaN and SiC, blue and white LED have achieved the successive research success, which has made it possible to realize semiconductor white LED illumination. Compared with the traditional light source, as the semiconductor light source, high0-power white LED has the characteristics such as energy saving, environmental protection, low voltage and short switch time. Owing to the rapid development of the technology of high-power LED, there is a wide application prospect. However, the reliability of the device is the guarantee to realize its wide application.
Application of high-power white LED
High- power white LED is mainly applied in the lighting market; we need to specially design the product according to different requirement. Mainly there are the following aspects of application:
(1) Landscape lighting market: Including architectural ornament, interior decoration, tourist attractions decoration act. Mainly applied in the decorative lighting of major structures, streets, commercial center, places o interests, bridge, community, courtyard, lawn, home furnishing, public places of entertainment, as well as the commercial lighting.
(2) Auto market: Automotive market is the fast-growing market of LED application, it is mainly applied in the indicating light and the internal reading light of the car dashboard, air container, stereo, and the third brake light, tail light, steering lamp, side light etc.
(3) Back light market: LED as the back light has been commonly used in cell phone, computer, portable electronics etc.
(4) Outdoor large screen display and traffic lights: Owing to the advantages of high brightness ( Brightness Meter ), long life ( LED Life Test ), electricity saving ( Electricity Test ), LED has gained popularity among many fields such as banking, securities, traffics, airports. Especially, it has been the regular equipment for almost all the large stadiums in the world.
(5) Special lighting and military use: Because LED characteristics such as antiknock, moisture resistively, tightness, as well as the advantages such as low thermal radiation, small volume and light weight, it is widely applied in the special field or bad working environment such as antiknock, field work, diggings, military action.
(6) Other application: It is also applied in the light industrial products such as toys, gift, flashlight and Christmas lights. As the important production base of the global light industrial products,Chinahas huge market demand of LED.
