LED "two high and one low" technical problems need comprehensive solutions

The current technological development goal of the semiconductor lighting industry is to completely solve the "two high and one low" technical problems, namely, high energy efficiency, high quality (including light quality and reliability), and low cost technologies. Only by properly solving these technical problems can we provide people with energy-saving, environmental-friendly, healthy and comfortable lighting environments. To solve the "two highs and one lows" technical problem, solutions should be proposed from the main parts of the industry chain, namely, substrate, epitaxy, chip, package and application.

Substrate, epitaxy, and chip technologies continue to break through the global episode and there are 142 chip companies. China has put into production 36, and plans to build 25 companies. There are about 2800 MOCVD existing in the world, more than 700 in China, and about 400 production units. In 2011, global chip production was 82 billion, and in 2012 it is expected to reach 95 billion, and the chip production capacity will be 35%. At present, the lab efficiency of white light can reach 254 lm/W, industrialization is 140 to 150 lm/W, and Cree has recently launched a 160 lm/W product. At the same time, the blue light efficiency reaches 300 lm/W, the red light efficiency reaches 240 lm/W, and the green light efficiency reaches 160 lm/W.

For patterned substrates (directional, nanometer) and semi-polar, non-polar substrates, good results have been achieved by improving processes, simplifying processes, saving raw materials, and reducing costs; for homoepitaxial aspects, many Methods The production of GaN substrates and the growth of GaN LEDs on GaN substrates greatly reduced the use of MO sources and high-purity gas, and it was predicted that the cost could be reduced by 50%.

GaN is grown on 8-inch Si substrates. Many companies around the world have already invested in R&D. Due to the availability of existing redundant production equipment and the simplification of process flow, the cost will be greatly reduced. At the same time, Aixtron introduced an Si-based epitaxial furnace, which can strictly control the degree of bending and achieve uniform production. This will undoubtedly promote the growth of epitaxial growth on 8-inch Si substrates, and significantly reduce costs.

The new extension technology of Japan Insists Inc. has greatly reduced the dislocation density, greatly improved the LED performance index, and achieved a breakthrough.

In the chip structure, a variety of new structures have emerged, the hexahedron light emitting chip is more typical, and the multi-faceted surface roughening technology is adopted to reduce the interface reflection and increase the light extraction rate, thereby increasing the external quantum efficiency. Samsung's LED technology using nano-hexagonal pyramid technology can achieve semi-polar, non-polar growth of GaN, good heat dissipation, good crystal quality, and multi-color white LEDs, achieving a breakthrough.

According to related reports, comprehensively, many of the major technological innovations of epitaxy and chips are mostly key technical issues aimed at improving performance and reducing costs. Therefore, there are institutional experts analyzing and predicting that the outsourcing cost will be 25% per year in the next 10 years. reduce.

In summary, due to continuous breakthroughs in GaN epitaxial and chip technologies, different dislocations, new structures, and nanoscale technologies can be used to grow GaN with low dislocations and make high-efficiency LEDs. In the absence of wavelength conversion, its light efficiency can exceed 300lm / W (theoretical value up to 400lm / W); the use of phosphor wavelength conversion, light efficiency can exceed 200lm / W (theoretical value up to 263lm / W), but also Develop a new technology route for multi-color on a single chip. At the same time, the use of new technology and wafer technology growth and extension, can greatly reduce the epitaxial, chip production costs.

Modular standard packaging into the direction of development China's LED packaging technology has made great progress in recent years, the overall level of packaging and foreign differences is very small, even quite, but the key packaging material also imported. In 2011, the value of global packaging devices was 12.5 billion U.S. dollars, with a growth rate of 9.8%. Another report reported that the output value was 11.2 billion U.S. dollars and 13.78 billion U.S. dollars, but due to the lack of estimates by these institutions on the Chinese packaging industry (less than 1 billion U.S. dollars), The actual output of the package should be around 16 billion U.S. dollars. The world's top ten packaging companies are Nichia, Samsung, OSRAM, LG, Seoul Semiconductor, Cree, Philips, Sharp, Toyota Synthetic, Everlight, etc., accounting for 68% of the global market. The output value of packaging devices in China is about 25 billion yuan, and more than 40 companies have output value of 100 million yuan or more. The luminous efficiency of devices is 120 to 130 lm/W, and imported chips can reach 140 to 150 lm/W.

In order to improve light extraction efficiency, package reliability, and cost reduction, the industry has made great progress using SMC composites, DMS high-conducting materials, various ceramic materials, phosphor coating processes, and new packaging structures.

New technologies such as new phosphors, graphene heat dissipation, and quantum dots are emerging. The multiple COB new structures of independent innovation in China have many advantages and can reduce the cost by 10% to 30%. At present, COB light efficiency has reached 130 ~ 150lm/W.

At the same time, the module, driver, control part, heat dissipation, parts, etc. are packaged together to form a module, and modularized packaged LED products for standardized production become the development direction of semiconductor lighting sources. The Zhaga Consortium has formulated more than a dozen draft standards for this purpose, mainly the light engine interface interface standards, including physical dimensions, optical, electrical and thermal characteristics.

Some experts predict that due to the use of direct eutectic soldering and modular standard packaging technology, in another 5 to 10 years, LED packaging companies will no longer need to package LED lighting devices, but will be packaged and assembled by lighting companies.

According to relevant reports, due to the significant cost reduction of epitaxy and chips, the adoption of new technologies for packaging will further reduce costs. Therefore, there are institutional forecasts, LED device prices will be reduced at an average rate of 20% in recent years.

In summary, the packaging technology adopts new structures, new processes, and nano-level technologies, and has made breakthrough progress. In the future, it may be possible to use alternative phosphor encapsulation technologies. Modular packaging is used in the field of lighting. Individual packages of LEDs are not required. Applications may use products with different packaging technologies. Therefore, the cost of the device will be greatly reduced and the enterprise must have the ability to afford it.

The market prospects for lighting applications are promising. With the continuous improvement of LED performance, the scope of LED lighting applications continues to expand, which promotes the rapid development of the semiconductor lighting industry. In 2012, the global lighting output value was 140 billion US dollars, of which LED lighting accounted for 11%, 15.4 billion US dollars. In 2011, the output of LED lighting in China was 180 million, of which 47.4% were bulb lamps, 22.8% were spotlights, 12.1% were straight lamps, and 7.3% were downlights. In the first three quarters of 2012, the export of LED lamps increased by 40%, and the market prospects are promising.

In terms of energy efficiency, although the current theoretical value is up to 56%, the actual total energy efficiency is only 20% to 30%. To achieve a total energy efficiency of more than 50%, there are still many technical problems to be solved, and the difficulty is also great. Lifetime, LED chip life of up to hundreds of thousands of hours, the device up to 50,000 to 100,000 hours. ENERGY STAR Luminaire V1.0 technical specifications stipulate that the life span of integrated LED lamps is between 15,000 and 25,000 hours. In terms of comfort and safety, relevant standards are also being developed.

In the era of LED lighting, enterprises should give full play to the advantages of LED lighting, and fully transform and innovate traditional lighting fixtures. Increase efforts to design new lamps, such as embedded lighting, plane lighting, bar lights, flexible light sources, art lights, etc., to make the lighting environment more gentle, comfortable and personalized.

In intelligent digital control, indoor intelligent lighting systems are suitable for commercial lighting and home lighting; outdoor intelligent lighting systems are suitable for landscape lighting, public buildings and road system lighting; professional intelligent lighting systems are suitable for art-specific lighting. The Global Connected Lighting Alliance was established in September 2012 by six lighting giants (Philips, Osram, Panasonic, Toshiba, GE, Lutron) to promote the implementation of lighting wireless network control systems. Through intelligent digital control, lighting will be personalized, comfortable, dimmable, color-tuned, and secondary energy-saving. This is the direction of development of lighting systems.

In the development of ecological agriculture, LED light source can be applied to plant growth, livestock and poultry breeding, pest control and so on. Both developed countries and major LED companies have been involved in the application of this field.

In summary, the final energy efficiency target of LED lighting products will reach more than 50%. The quality of the light source must meet the requirements of comfort and safety standards. LED lighting fixtures must be fully innovative and adapt to the needs of modern LED lighting. The application of intelligent control systems will be lighting. The direction. In addition, pay attention to the application of LED lamps in the non-lighting field.