LED projector, headlights and lighting of the gospel: OSRAM LED new structure can inhibit the big

OSRAM GmbH semiconductor (OSRAM Opto Semiconductors) has developed an external quantum efficiency of up to 68% LED technology. Allegedly, even if the increase in the amount of LED input current, still can get higher efficiency. 68% of the external quantum efficiency is the luminous wavelength of 440nm, the shape of the size of 1mm x 1mm blue chip LED to achieve the value of. This blue LED chip light output, when the input current of 350mA up to 640mW, when the input current of 3A up to 3.2W. The company said that if the blue LED chip coated fluorescent system into a white LED chip, the luminous efficiency of up to 136lm/W, when the current time into the 3A flux up to 830lm. In the green LED chip using this technology, when the current input 1A can get 224lm luminous flux. The company said that due to this feature, the new product is suitable for use RGB LED projector light source. In addition, the utility model is also suitable for lighting and automotive headlamp.

OSRAM will develop the technology called UX:3". A higher external quantum efficiency was obtained by modifying the configuration of the N type contact electrode of the class LED technology "ThinGaN" of the company GaN. Specifically, will be based on the use of ThinGaN technology in the past GaN class LED chip surface type n contact electrode removed from the surface, and implanted into the LED chip internal. In this way, when the light generated from the inside of the LED chip is shot out of the chip, the shielding efficiency is improved. N type contact electrode (Fig. 1 Pillars on the right side of the Current Spreading) through the P type semiconductor layer (Figure GaN in the P-layer) of the through hole and N type GaN semiconductor layer (N-layer in Figure 1) electrical connection. In order to avoid the short circuit of the n contact electrode and the P type contact electrode (Metallic 1 in figure Mirror, and the Ag base layer acting as a light reflecting layer), an insulating layer is arranged between the two electrodes.

Figure 1 on the left side of the LED chip using ThinGaN technology, the right side of the LED chip using UX:3 Technology

Also, the company said, due to the current density, the UX:3 technology can reduce the multiple quantum wells LED as the active layer part of the result, the LED drive current time increases the quantum efficiency of LED will decrease the problem can be reduced (Figure 2). Therefore, higher quantum efficiency can be obtained even if the input current is increased. According to OSRAM, the more the driving current, the greater the quantum efficiency of the reasons for the decline of Auger recombination (Auger recombination). Auger recombination is a kind of non radioactive recombination which is not accompanied by luminescence, and the higher the current density, the more the Auger recombination will increase. The company's view is that because the UX:3 technology can reduce the current density to a minimum, thus reducing Auger recombination, reducing the quantum efficiency. (Editor: maysoong)

Fig. 2 Variation of light output relative to input current. Compared with the previous technology, the output of UX:3 is larger when the input current is large