Short-wavelength III-V LEDs and their applications

摘要

III-V nitride semiconductors are suitable for LEDs having color range from blue to green. Luminous intensity and color purity of these LEDs are so high that they have been used for many applications for full color display and LCD backlight and so on. In addition to natural colored LEDs, we have developed short wavelength LED, named TG Purple, which wavelength is typically around 380nm. TG Purple has been realized by controlling Indium composition in GaInN well layers. It can activate photo-catalysts such as TiOx, and therefore, the air purifier for automotive has been developed by combining TG Purple and TiOx photo-catalyst. The short wavelength LED is now the best light source for automotive air purifier using photo-catalyst, because LEDs fulfill the mercury-less requirement for an environmental issue and don't need special circuit like conventional UV lamps such as black light lamps and cold cathode lamps. Furthermore this short wavelength LED is used for phosphor excitation that generates many colors like blue, green, red, etc. It is likely that, with this technology, LEDs will take some part in illumination market as one of primary light sources like incandescent lamps and fluorescent lamps.