As a strategic emerging industry in China, semiconductor lighting is of great significance to energy conservation and environmental protection. China is a global producer, use and exporter of semiconductor lighting products. However, in the field of special LED light sources, the market has been monopolized by foreign companies due to the high technical threshold.

Recently, the team of Xia Dazhao, a researcher of the Light Health Center of the Suzhou Medical Institute of the Chinese Academy of Sciences, and the Suzhou Branch Medical Science and Technology Shikai Semiconductor Co., Ltd. jointly announced the "Technology Invention Award for Ultra High Power, High Optical Density and Multispectral Special LED Light Source Technology and Application". First prize.

Focus on high-end market for LED applications

Due to the huge market potential, LED-related industrial applications are rapidly expanding from general lighting to almost all areas. Different from general lighting, lighting applications in some special fields have also received more and more attention, and the market prospects are increasingly optimistic, and these applications rely on special LED light sources.

Xiong Dazhao said that special LED light sources are a kind of LED light source that pursues more light energy in a small light-emitting area. It requires a single module to have high electric power and power density, and the intensity is similar to that of laser. The special LED light source technology started in 2000 and started very slowly. Domestic companies have almost no production. In foreign countries, only two high-tech starting companies, Osram and Longmings, can provide them.

The reason is that there was a lack of large-sized vertical structure LED chips in China at the time. At the same time, special packaging technology, heat dissipation technology, optical design and integration technology were not enough.

Since 2009, in order to break through the monopoly of foreign manufacturers in this field, Xiong Dazhao led the team with the support of the Chinese Academy of Sciences, Jiangsu Province, Suzhou City and High-tech Zone, focusing on the development and industrialization of special LED light sources, in the ultra-high power LED light source. R & D, design and manufacturing technology focused on research and development, and made new breakthroughs.

The research team has established technical advantages and cooperated with Suzhou Science and Technology Shikai Semiconductor Technology Co., Ltd. to carry out industrialization work and provide solutions for ultra-bright high-density LED chip light sources.

Xiong Dazhao said: "The special LED technology we developed, focusing on the high-end and special markets of LED applications, using different technical routes, has produced a series of original technologies and core patents, breaking the monopoly of foreign products and helping China in emerging segments. Leading the field abroad and enhancing the core competitiveness of the manufacturing industry."

Unique LED chip light source technology

Under the efforts of R&D personnel, the research team broke through various obstacles and finally formed a technical route with independent intellectual property rights.

Xiong Dazhao said: "For special LED light sources, we need a large, based on the vertical structure of the chip's light-emitting surface. We have developed a 'quasi-single chip' package technology, using a special process, using a small-sized vertical structure chip to ultra-tightly package into a high power. Module."

This technology not only produces high light output on the same light-emitting surface, but also allows flexible use of small chips to increase the light-emitting area and thus increase the total light output.

"The maximum electric power of the United States Rammings single module is less than 150W, and our single module electric power can reach more than 600W. The foreign company is based on a single large chip technology light source, the light emitting surface is generally rectangular, and our chip, light The surface can be flexibly configured to match any particular optical system to any shape," said Xiong Dawei. At present, products based on ultra-high optical density integrated package module technology have become the mainstream in the market.

In the previous special LED light source products, foreign manufacturers could only provide white light, or monochromatic light of one of red, blue and green. Faced with the demand for spectroscopy in special fields such as biomedicine, the team has developed a multi-spectral high optical density module.

On a tiny 2.5 mm x 2.5 mm illuminating surface, 16 wavelengths of narrow-band light can be integrated, and the wavelength of each light can be arbitrarily selected. This technology uses electronic control instead of mechanical control, which greatly simplifies the structure of various optical instruments, and revolutionized a variety of biomedical instruments such as high-end fluorescence microscopy and ophthalmic full-spectrum fundus detectors.

At the same time, the team also studied the substrate material of high thermal conductivity vertical structure chip, the choice of high thermal conductivity solid crystal material, the thickness control of the solid crystal layer, the baking temperature and time control, and the design of the package substrate. Based on these technical combinations, The thermal resistance of the 600W module can be as low as 0.10K/W, leading the world.

Market segment is applied

Since the R&D work in 2009, after years of improvement and accumulation, the products launched by the team have been gradually promoted in the market since 2010. Currently, they have been widely used in some market segments, and some of them have become mainstream products.

“60%~70% of the world's stage lighting is produced in China, with a total output value of tens of billions of yuan, and about 800 manufacturers. The high-density, high-power LED special light source was mainly provided by American companies. Our products from 2012 onwards. Entering the market, 200 customers have been accumulated, and American products have been marginalized,” said Xiong Dajun. Not only that, but the Suzhou Medical Institute has appeared in the projection display market, long-range lighting and long-distance lighting markets.

In 2014, with the support of the “璀璨 plan” of the Chinese Academy of Sciences, the team officially launched the development of ultra-long-range floodlights. Last year, the team successively developed bombing lights based on high-power high-brightness LED light sources. Three of them have been successfully applied to a logistics support force; small-scale LED searchlights produced in batches have been used in Kunming airport bird-removal warning vehicles.

Xiong Dazhao said: "Special LED light sources have begun to play a major role in modern molecular biology research and medical lighting, diagnosis, treatment and rehabilitation physiotherapy. Among them, narrow-band multi-spectral light sources have been applied to multi-band fluorescence microscopy, small batch production in 2017. 11 sets; super-resolution structured light microscopy based on high optical density special light source has been successfully developed, the imaging quality and imaging speed have reached the international leading level, the cost is far lower than the competition, and the market prospect is very wide."

Now, the team is also aiming at the emerging LED-based light health direction. Xiong Dazhao told reporters that the research on LED light health engineering includes photo-defense prevention, early prevention and detection of diseases, phototherapy of diseases, rehabilitation and photo-therapy. In 2016, the National Key Laboratory of Semiconductor Lighting Joint Innovation, in conjunction with Suzhou Medical Institute, set up the Light Health Research Center in Suzhou, and is committed to developing and developing special LED light sources in the field of light health.

"At present, the research group has developed a variety of infrared physiotherapy instruments based on infrared LED chips, including handheld and vertical and three horizontal types that are being processed and adjusted. Special LEDs are especially suitable for home health care for the elderly. Wearable light therapy physiotherapy equipment, according to the size of China's population and the trend of population aging, the scale of this market will reach hundreds of billions." Xiong Dajun said.