The luminous efficiency of LED is a main factor to measure whether the photoelectric convertor is efficiency. How to improve the luminaries efficiency. This article introduces effect way to improve the luminaries efficiency of LED from the surface microstructure technology.
The surface microstructure technology is another technology to improve the luminous efficiency of devices. The main point of the technology is a mass of microstructure that is the size of light wavelength scale sculptured on the surface of chips. Every structure that is tetrahedron,therefore,not only expands the light area,but also the refraction direction of light on the surface of chips changes, which improves the relative illuminance obviously.The chip of LED with texture structure has N kinds of light pattern,because of the exist of the texture, makes lots of light that is larger than critical angle via the reflection or refraction of the eadge to pass the surface of the devices. Obviously, the exist of texture structure on the surface, equals to add the thickness of the window layer by a large margin.The thickness of the window layer is thinner,the texture structure sculptured deeper, and the addition of the light out-coupling efficiency becomes more obvious. Measure points out that the window layer thickness of device is 20 μm,the luminous efficiency can increase 30%.When the window layer thickness decreases to 10 μm, the luminous efficiency would improve 60%. For 585-625 nm wavelength of LED devices, after manufacturing the texture structure, the luminous efficiency can reach to 30 lm/w, and the value has been reached the level of transparent substrate devices.