High luminous flux and high power LED and its application

1. Development History and Application Potential of LED Since its birth, LED has developed rapidly according to the "Haitz" law that the brightness increases 30 times and the price decreases 10 times every 10 years. Ordinary high-brightness white LEDs have reached the level of 100 lm/W in the laboratory, and 50 lm/W high-power white LEDs have also entered commercialization. In terms of monochromatic light, the light efficiency of red, yellow, blue and green light has also been constantly breaking records. As a new light source, the application range of LED is getting wider and wider, and it has gradually attracted more people's attention and expectations. At present, LED applications are diversified and distributed in various industries, including indication, display, backlight, lighting, etc. Lighting is the most promising industry among many LED applications. With the continuous improvement of LED light efficiency and the continuous reduction of cost, its market share in the entire lighting field will also expand. Following the "Next Generation Lighting Plan" of the United States, the "21st Century Lighting Plan" of Japan, the "Rainbow Plan" of the European Union and the "Solid State Lighting Plan" of South Korea, my country established the National Semiconductor Lighting Engineering Group in 2003 to integrate resources and quickly promote LED into the lighting market. According to the prediction of Academician Chen Lianghui of the Chinese Academy of Engineering, between 2005 and 2015, semiconductor lighting in my country can save 400 billion kWh of energy, save 260 billion yuan in electricity bills for users, create 150 billion yuan in output value, and solve the employment of 1 million people. By then, the annual electricity saved by semiconductor lighting will exceed the annual power generation of the "giant" Three Gorges Power Station! In the context of increasing energy shortage, the development of LED lighting by utilizing the energy-saving characteristics of LED is a positive response to the government's proposal to build a conservation-oriented society.

2. Characteristics of high-power LED and comparison with other light sources LED is well-deserved to be called "green light source". In the lighting industry, comparing and analyzing it with traditional light sources, some aspects show irreplaceable advantages: LED as a light source for lighting has the following advantages:

1. Low power consumption: LED with a luminous efficiency of 75lm/W consumes about 80% less power than an incandescent lamp of the same brightness;

2. Long life: The product life is up to 50,000 hours, and it can be used for 7 years with 24-hour continuous lighting;

3. Easy dynamic control of brightness and color: continuous adjustable brightness, high color purity, dynamic color change and digital control;

4. Flexible dimensions: It can be organically integrated with the building to achieve the effect of only seeing the light but not the lamp;

5. Environmental protection: no harmful metal mercury, no infrared and ultraviolet radiation;

6. Color: bright, saturated, pure, no filter required, can be adjusted to various colors with red, green and blue elements, can achieve variable, gradual, mixed light effects, excellent color rendering effect. With so many advantages in one, we feel that vigorously promoting the use of LED is a very valuable work. However, LED also has shortcomings compared with other light sources, such as low color rendering in white light illumination. At present, the color rendering index of white light LED produced by yellow phosphor and blue light is about 80. It is OK for general lighting, but it is insufficient for some places with high color resolution requirements. Although the color rendering index can be increased to 90 or higher by adding appropriate red phosphor and other methods, there is still a certain gap compared with the 99 of incandescent lamps, and its efficiency will be affected. The color rendering can also be improved by RGB color mixing, but more work needs to be done in the popularization and application of technology, so LED still needs to be improved in terms of color rendering. As for the high price and large one-time investment, in fact, considering the comprehensive cost, the use of LED in many occasions still saves a lot of cost. Table 1 below is a comparison of the lifespans of incandescent lamps, fluorescent lamps, ordinary LEDs and high-power LEDs. It can be seen from the table that high-power LEDs have a great advantage in lifespan, and there is little room for improvement in many technical aspects of incandescent lamps and fluorescent lamps.