According to foreign media reports, Nitride Semiconductors, a Japanese UV LED manufacturer, announced that it has obtained a patent for Micro UV LED high-efficiency technology in the United Kingdom, Germany and France on September 8, 2021, with the patent number 3644379; the other was obtained in the United States on October 5, 2021. The same patent, the patent number is 11,139,342. The new patented technology obtained by Nitride this time helps to excite red, green and blue phosphors to prepare a full-color display.
With the help of superlattice structure and patterned sapphire substrate to reduce the chip size to 50 microns or less, this new patented technology can improve the luminous efficiency of 385-400nm Micro LED chips. The luminous efficiency of other color LEDs will be reduced due to size reduction, but this new patented technology of Nitride can suppress the reduction in efficiency.
In general, it is difficult and time-consuming to bond LED chips with a size of 20-30 microns on a TFT display panel. Nitride said that the red, blue, and green LED chips are unified into a UV LED, which is convenient for chip bonding and current and voltage control. In addition, Micro UV LEDs can excite RGB phosphors to achieve full-color display.
Although there are opinions that the luminous efficiency of UV LEDs is low, Nitride believes that this high-efficiency technology is expected to greatly enhance the feasibility of Micro LED displays.
It is reported that in 2000, Nitride Semiconductors and Professor Shiro Sakai of the University of Tokushima in Japan developed the world's first high-efficiency UV LED product. Since then, it has invested heavily in the research and development of UV LED technology.
In the first half of 2021, the Nitride research team used Micro UV LEDs to excite red, blue, and green phosphors, and successfully scaled the Micro UV LED chips to 12μm x 24μm. The distance between the chips in the horizontal and vertical directions is both 5μm, can be used on Micro LED displays, and is expected to be applied to wearable devices such as next-generation AR glasses and smart glasses.
Nitride said that this technology can reduce the cost of Micro UV LED chips for displays. Currently, Nitride is developing technology for mass production.
