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• Time of issue:2012-09-21 13:25
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(Summary description) LED future technology development trend The characteristics of LEDs are small and light, low driving voltage, full color, long life, high efficiency, vibration resistance, and easy light control, which provide excellent conditions for designing lighting systems for different places and purposes. People are accustomed to looking at things in sunlight. For general lighting, people mainly need light sources that are close to the quality of sunlight, so white LEDs are an important indicator of semiconductor lighting technology. Due to the low power and low brightness of a single LED, it is not suitable to be used alone. For this reason, multiple LEDs must be assembled together to design a practical LED lighting system. However, there is still a certain distance between white LEDs and general lighting requirements, and there are still many technical and cost problems that need to be solved urgently. Main technical overview of semiconductor lighting system 1) Thermal management of lighting systems LEDs are generally referred to as cold light sources, because the principle of LED light-emitting is that electrons directly emit photons through recombination without the need for heat. However, due to the existence of Joule heat, LEDs are accompanied by heat while emitting light, and for high-power and multiple LED applications, the heat accumulates and cannot be underestimated. LEDs are different from traditional lighting such as incandescent lamps and fluorescent lamps. Light source, too high temperature will shorten or even terminate its service life. Moreover, LED is a temperature-sensitive device. When the temperature rises, its efficiency drops sharply. Therefore, system structure design and heat dissipation technology development are also issues that LED applications need to face. Since forced air cooling is generally not desirable in light sources, heat sinks and other methods of enhancing natural convection cooling play an increasingly important role in LED lamp and light source designs as input electrical power increases. 2) Improve color rendering At present, white light LEDs generally use blue light-emitting LEDs superimposed with yellow light-emitting yttrium aluminum garnet (YAG) phosphors excited by blue light to synthesize white light. Since its luminescence spectrum only contains blue and yellow spectrums, there are problems of high color temperature and low color rendering index, which do not meet the requirements of general lighting. The sensitivity of the human eye to chromatic aberration is much higher than that of light intensity. For lighting, the color rendering of the light source is often more important than the luminous efficiency. Therefore, adding an appropriate amount of red-emitting phosphor powder and maintaining a high luminous efficiency is an important issue in LED white light illumination. 3) Secondary optical design of lighting system Traditional lamps and lanterns have long used incandescent and fluorescent light sources as reference objects to determine the optical and shape standards of lamps. Therefore, LED lighting systems should consider abandoning traditional lamps and LED light-emitting modules. LED light sources are specially designed for different lamps. The design of the optical system mainly includes the following aspects: ① According to the requirements of lighting objects and luminous flux, determine the shape of the optical system, the number of LEDs and the size of the power; ② Combine several LED light-emitting tubes to design a point light source, a ring light source or For the "secondary light source" of the surface light source, the lighting optical system is calculated according to the combined secondary light source; 3. The control of the light distribution of each LED tube on the "secondary light source" that constitutes the lighting optical system design is very important. Since the light beam emitted by the LED is concentrated, it is easier to control, and no reflector is needed to focus the light, which is beneficial to reduce the depth of the lamp. For example, using a flat mirror optical system, only 1-2 LEDs can be used to illuminate a large surface, and the depth of the lamp is very thin; and using light guide technology, the LED is directly installed next to the light guide, which can greatly reduce the light source and other components. Occupied volume, made into ultra-thin lamps. The above content is edited and reprinted by Nanjing Tansu Optoelectronics www.njtan suo.com Our company is the first company in China to use long strip flameproof LED roadway lights for mine lighting. Also produces LED downlights, LED ceiling lights, LED street lights, LED landscape lights, etc.