Different applications of LED technology trends

Backlights, displays, and lighting are currently the three largest and most promising applications markets for LEDs. Different markets, different needs. In different application areas, where will LED technology develop? What are the attributes that companies should strive to improve? "China Electronics News" interviewed well-known experts in the industry and representatives of leading companies to interpret the development trend of LED technology in different applications.

Data show that China's LED display application industry is generally stable. The number of companies with LED display business in China is about 400. In 2012, the total sales of LED display screens nationwide was 25.3 billion yuan, an increase of 15% compared to 2011; in 2013, the market size of the LED display application industry in China was increased by approximately 10% to 15%, and the total market volume was 28 billion yuan. about.

"The development of LED display application market has entered a relatively stable period." Guan Jizhen, vice chairman of the China Optical Optoelectronics Industry Association and chairman of the LED Display Application Industry Association, said in an interview with "China Electronics News" reporters, "The level of technology in LED display With continuous improvement, innovation will become an important manifestation of the competitive advantages of the corporate market."

Machine: Technical Level and International Synchronization

“At present, China’s overall LED display technology level is basically in sync with the international development, and it is still at the leading international level in some key technology areas and special engineering applications.” Guan Jizhen said, “Innovative products are new, especially with small dots. High-density LED display products, new LED curtain wall display products, and professional control boards and control systems are prominent."

Guan Jizhen told reporters that from the perspective of overall technological innovation, some key enterprises actively undertake various kinds of science and technology projects, and are supported by special projects of energy conservation and industrialization of the National Development and Reform Commission; the overall technological innovation direction of the industry is mainly concentrated on large-screen control and high density. Display new product development, special project engineering design, LED display application development products and product reliability, energy saving and other aspects; in the field of traditional LED display, various indoor and outdoor LED display key technology is basically mature, the whole product is reliable The continuous improvement and perfection of the sex and craftsmanship level have led to the formation of a standardized series of products; full-color indoor and outdoor displays have been widely used, and outdoor high-definition full-color surface mount technology products have become increasingly mature.

So for the LED display industry, the next step in the direction of the development of the technology? "We must improve product quality as a breakthrough for technological innovation." Jiang Fengyi, vice president of Nanchang University and director of the National Silicon-based LED Engineering Technology Research Center, told the "China Electronics News" reporter.

Jiang Fengyi suggested that the development and application of reverse polarity LED chips, and reduce the operating current density, improve luminous efficiency, improve reliability, make the display more energy-efficient. The application of reverse polarity red LEDs can greatly increase the luminous efficiency; for red LEDs, their operating current density can be reduced, which can significantly increase their reliability; and green LEDs can also significantly increase their luminous efficiency by reducing their operating current density. At the same time, it is possible to develop high-quality LED displays with various colors such as monochrome screens and multi-combination dual-color screens.

"These technological innovations are inseparable from close cooperation with the midstream and downstream." Jiang Fengyi said, "The key to the joint innovation of the industrial chain to promote LED applications is to avoid overloading the chip, work with a lower current density, use more chips, and reduce The stringent requirements of power supply and heat dissipation will further increase the luminous efficiency and reliability of LED application products while maintaining the total manufacturing cost unchanged or changing little.”

Chip: "Four High" corresponds to more requirements

So, what kind of LED display is really a high-quality display? “I think this is mainly reflected in six aspects.” Jiang Zhongyong, general manager of Hangzhou Shilan Mingxin Technology Co., Ltd., told the “China Electronics News” reporter, “One is that the LED display has good uniformity, that is, the uniformity of brightness and color is good; the second is Display does not die or rarely die; Third, low gray uniformity is good; Fourth, after long-term use, the above indicators change little; Fifth, LED brightness is high, saving electricity; Sixth, the surface is flat.

Brightness enhancement is an eternal topic for LED chip manufacturing. In addition, as one of the leading factors determining the quality of LED display screens, what are the specific effects of the chip's technical level on the quality of the display screen? Jiang Zhongyong stated that the specifications of the chip determine the specifications of the package, and the requirements for uniformity are increasing; the level of electrostatic protection of the chip is inseparable from the long-term stable operation of the display; the more uniform the junction capacitance of the chip, the better the uniformity of low gray levels; The chip also determines the proportion and level of small LED display leakage.

Specific to the indoor display, the "four-high" attribute of the high-quality LED display puts specific requirements on the chip. Dr. Wang Jiangbo, research and development department of Huacan Optoelectronics Co., Ltd., said in an interview with “China Electronics News” reporter that the first is “high density”, the chips are getting smaller and smaller, and the requirements for consistency are higher and higher, but for single chips The brightness requirement becomes lower; followed by a "high scan", the higher the scan frequency, the longer the chip is in the back pressure state, and the corresponding chip performance must also be improved; the second is "high refresh", the higher the refresh rate, the The higher the chip's tolerance to high-frequency pulse currents, the last is a "high gray level", which requires better wavelength and brightness uniformity at various currents.

"For outdoor displays, from the straight-line tube to the 3535 surface mount, the chip requires better light-type consistency, higher brightness, better moisture and moisture resistance," stressed Wang Jiangbo.

Devices: Five Trends Lead to Technological Development

LED display devices are another dominant factor in determining the quality of LED display screens. “At present, the five trends are leading the development of industry technology.” Li Mantie, chairman and president of Shenzhen Lehman Optoelectronics Technology Co., Ltd., said in an interview with a reporter from China Electronics News.

Lower and lower operating costs are the constant pursuit of LED display operators. "The first trend is that the brightness of LED devices continues to increase, and the power consumption of display screens continues to decline," Li Mantie said. "Only this can continue to reduce the operating costs of LED displays."

Light pollution, which is everywhere, has affected ordinary people's lives. Following last year's Shanghai Municipality's first introduction of mandatory standards for LED display brightness restrictions in public places, from May 1st this year, from 22:30 everyday to 7:30 the next day, outdoor LED display screens in Guangzhou are required shut down. "The management of light pollution in LED displays has gradually formed a consensus, so the second trend is that LED devices must reduce light pollution." Li Man Tie said.

The third trend is that surface mount devices are moving from indoor to outdoor. “By continuing exploration of mechanics, thermal sciences, materials science, optics, and other comprehensive disciplines, the reliability of outdoor application of surface mount devices has been greatly improved. Waterproof, moisture proof, and UV resistance have been able to basically meet the needs of outdoor applications.” Li Mantie said "At present, it seems that the technology of surface mount devices from indoor to outdoor has matured."

“The pursuit of outdoor high-definition display by users is never-ending, and LED high-definition display records are constantly being refreshed.” Li Mantie said, “The pitch of LED screens is getting smaller and smaller, and the device size is getting smaller and smaller. This is the fourth a trend."

The last development trend is reflected in the display effect of the screen. “In the industry, by adopting the technology of improving the contrast of surface mount devices and matt surface matte technology, the display effect of LED devices has been greatly improved.” Li Mantie said, “But with the continuous improvement of the display quality requirements of the market, LED The device should also meet the higher requirements for picture quality."