The improvement of the luminous efficiency of LED chip determines the energy saving capacity of LED street lamps. With the development of epitaxial growth technology and multiple quantum well structure, the internal quantum efficiency of epitaxial wafers has been greatly improved. How to meet the standard of street lighting depends largely on how to extract the most light from the chip with the least power. In a simple sense, it is to reduce the driving voltage and improve the light intensity. The LED chip structure of the traditional dress, usually coated with a layer of translucent conductive layer on the p-GaN makes the current distribution is more uniform, and the conductive layer of light emitted by the LED have some absorption, and p electrode will block part of the light, the light efficiency which limits the LED chip. While the use of LED flip chip structure, not only can avoid the conductive layer on P electrode and the electrode pad absorbs light shading problems, but also through the reflective layer of low ohmic contact to the light guide to set down on the surface of p-GaN, it can also reduce the driving voltage and high light intensity.
On the other hand, the graphical sapphire substrate (PSS) technology and chip surface roughness can also increase the output of the LED chip by more than 50%. PSS structure is mainly to reduce the total reflection of photons in the device and increase the efficiency of light. The chip surface roughening technology can reduce the loss of light reflected at the interface when the light is emitted from the chip to the chip. At present, LED chip uses inverted structure and graphical technology, 1W power chip white light package, 5000K color temperature, the highest light effect of 134lm/W.