For semiconductor lighting, everyone is very concerned about LED light efficiency and light decay, life and Other characteristics. For example, in the early days, everyone had an unwritten consensus that LED light pipes with a luminous efficacy of less than 80 lm/W were not used for street lamps. LED street light products that were put on the market in line with light efficiency requirements did indeed have light decay. The problem has not been removed for a long time and has been removed from the pole. So far, everyone still pays special attention to these two issues. In fact, the development of semiconductor lighting to today, the efficacy of the standard white LED (20mA) luminous efficiency of 25lm / W in 2001, developed to the beginning of 2009, Nichia published white LED at 20mA current, its luminous efficiency of up to 249lm / W , the most in the industry. The high-power white LED (350mA) luminous efficiency has also grown from about 30lm/W in 2004 to the 161lm/W product published by Cree at the end of 2008, which is currently the best in the industry. Now, regardless of LED light efficiency or light decay, there has been a fundamental improvement. The current development of the semiconductor lighting industry is: LED lighting power supply and control circuits, LD (semiconductor laser) lighting and semiconductor lighting supporting policies must be highly valued.
Power supply reliability and control circuit is the fundamental guarantee for LED lighting promotion
According to statistics, at present, about 70% of LED white light lighting failures are power problems, about 20% are line and structural problems, and less than 10% are the quality problems of LED single tubes.
The choice of power management scheme is also important for energy saving, which requires the selection of the most suitable AC-DC driver in the drive circuit design. The common two-stage AC-DC driver power unit efficiency is 85%. If the efficiency is 90% constant current IC, the overall efficiency is only 77%. Assuming a 100 lm/W LED tube, the power efficiency problem alone reduced the road lighting efficiency to 77 lm/W (without considering other losses such as secondary light distribution). The high-efficiency AC-DC driver power supply module can achieve 90% conversion efficiency, so choosing an efficient and reliable power supply is the key to energy saving in semiconductor lighting.
Assume that the high-efficiency sodium lamp and LED street lamp have a luminous efficiency of 100 lm/W. Due to the strong directivity of the LED street lamp, under the same road illumination, it can save 50% of electricity (80% energy saving compared with incandescent lamps). A feature has been known to everyone. However, other characteristics of LED street lamps are superior to those of high-pressure sodium lamps, and have not attracted attention and utilization. For example, the controllable characteristics of brightness and the instant start characteristics of LED lamps have not been widely applied. We use these characteristics, through the control circuit can achieve time-sharing brightness control and when necessary, so that you can achieve 50% energy-saving indicators, so that the energy-saving effect of LED street lights is further enhanced.
At night, depending on the number of pedestrians and the specific conditions of the natural environment, we can control the different brightness of the LED street lights in different time periods, or directly shut down. When there is a pedestrian or vehicle at night, the sensor detects, for example, infrared image detection, automatically turns on the front 5 The street lamp is turned off after a delay of 3 minutes to achieve further energy saving of the LED street lamp.
Analysis of the luminous efficiency of various lamps can be seen that the light efficiency of various light sources is constantly improving, which requires us to make full use of other characteristics of LEDs to improve the energy-saving effect of LED light sources.
Semiconductor lasers are an important part of semiconductor lighting
A semiconductor laser is a special form of LED, referred to as LD. The fundamental difference between it and ordinary LED is single frequency and concentrated energy. Semiconductor lasers are widely used in laser sighting, laser phototypesetting, laser medical, laser ranging, laser communication, laser pointing, laser storage, gaming, military, bar code scanning, children's toys and landscape lighting, stage lighting, laser display, etc. Landscape lighting, stage lighting, and laser display are important components of semiconductor lighting. At present, China has included laser display in the high-tech development plan. The implementation of this plan will cause the third revolution in the TV industry. The advent of laser film and laser projection will fundamentally change people's lifestyle.
Under the guidance of the government's macro-policy and local incentive policies, through the strong alliance and development of the upper, middle and lower reaches of the optoelectronics industry, in the near future, the radiance of semiconductor lighting products will certainly illuminate every corner of the world.
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