Light-emitting diode is a solid-state semiconductor device, which can directly convert electricity into light.LED's heart is a semiconductor wafer, the wafer is attached to a bracket at one end, one end of the negative pole, the other end of the power supply is connected to the positive pole, so that the whole wafer is encapsulated by epoxy resin. The semiconductor wafer consists of two parts, one is a P-type semiconductor, in which holes dominate, and the other end is an N-type semiconductor, in which electrons dominate. But when these two semiconductors are connected, a "P-N junction" is formed between them.
When the current through the wire on the wafer, the electrons will be pushed to the P region, in the P region of the electron and hole complex, and then will be in the form of photons of energy, which is the principle of LED light. The wavelength of the light, which is the color of the light, is determined by the material that forms the P-N junction.
The main function of light-emitting diode (use):
The original light-emitting diode is a monochromatic light source, was used as a meter indicator, and then because of its good controllability in the digital tube and display technology, with the light-emitting diode brightness increase and color gamut of the expansion of the light-emitting diode, today, the light-emitting diode has been developed for a variety of purposes, used in all walks of life.
1, traffic signals
Traffic signals early use of LED equipment, mainly because the LED light source can directly emit monochromatic light, in the United States would have been the use of long-life, low-luminous 140-watt incandescent lamps as a traffic light, which produces 2000 lumens of white light. After the red filter, the light loss of 90%, leaving only 200 lumens of red light. After switching to LED light source, it only consumes 14 watts of electricity to produce the same light efficiency, which allows LED to quickly occupy the traffic light market.
2, LED display
In the nineties of last century, LED technology has advanced rapidly, LED display rapidly open up the market, the emergence of blue LED, LED display into the full-color era, and today, outdoor LED displays can be seen everywhere, become a bright figure in the advertising world.
3, automotive lighting
Ultra-bright LED can be made into automotive brake lights, taillights and directional lights, can also be used for instrumentation lighting and interior lighting, it is vibration, power saving and long life than incandescent lamps have obvious advantages. Used as a brake light, its response time of 60ns, much shorter than the incandescent 140ms, driving on a typical highway, it will increase the safety distance of 4-6m. LED as a recognized, low-carbon and environmentally friendly typical representative of low voltage and high luminous efficacy and other characteristics of the automotive lighting field so that it quickly become the darling of the automotive lighting field, thus forming a tens of billions of dollars, or even hundreds of billions of dollars! Market demand, LED automotive lighting market outlook is promising.
4, LCD backlight
LED as the LCD backlight, it can not only as green, red, blue, white, but also as a color-changing backlight, there are many products into the production and application stage. Recently, the cell phone on the LCD screen with LED backlighting, to enhance the grade of the product, the effect is very good. The use of 8 blue, 24 green, 32 red BOSMFC-LED made of 15in (1in ≈ 2.5cm) LCD backlighting, up to 120W, 2500 lm, brightness 18000nits (nits, cd/m2).22 LCD backlighting has been made, only 6mm thick, not only color mixing effect is good, the color rendering index also reaches 80 or more! . The current large-scale backlighting is in the development stage, but has great potential.
5, lighting
As the light-emitting diode brightness and price reduction, coupled with long life, power saving, drive and control than neon lights easy, not only flashing, but also color changing, so with ultra-brightness LED made of monochrome, multi-color and even color-changing light columns with other shapes of the various colors of light-emitting units, decorative tall buildings, bridges, streets and plazas and other landscapes. Project results are very good, presenting a colorful, starlight flashes and stream of colorful scenes. There have been a number of units to produce LED light columns of more than 10,000 meters, tens of thousands of colored lamps, LED lighting set up the city's embellishments.
6, lighting source
With the emergence of white LED, LED lamps and lanterns, the excellent performance of the rapid attraction of the major businessmen, with the continuous development of technology, today's LED lamps and lanterns and its luminous efficiency of 40%, incandescent lamps 8 times, tungsten lamps, fluorescent lamps 2 times, the direction of the light is strong, high utilization of light, but also a cold source of light, no heat radiation, known as "the fourth generation", and is the "fourth generation of light".
7, the medical market
With the light-emitting diode research continues to deepen, LED can improve sleep, support natural melatonin secretion, improve alertness, promote plant growth and other functions continue to be found, UV LED is widely sterilized in the field, the emergence of advanced LED blue-light therapy device, at any time, any place to release the appropriate blue light, to help relieve the pressure to regulate the mood, and effectively improve physical function. LED light source in the medical field applications continue to expand, the medical market must be another piece of LED equipment reserved for themselves.
Special characteristics of light-emitting diodes (and the difference between ordinary indicator lights):
Mention of light-emitting diodes, the first thing that comes to mind is its controllability, modern LED light-emitting successful integration of computer technology, often with IC control LED light-emitting diodes, is a programmable light source, which allows the LED can be flexible and versatile, the use of the principle of red, green and blue three-color, in the Computer technology under the control of the three colors with 256 levels of gray scale and arbitrary mixing, you can produce 256 × 256 × 256 = 16777216 colors, so that it can be applied in all kinds of instrumentation indicator, so that it is played in the city decoration, so that the city life to increase more colorful. In this regard, the blue jin photoelectric in the color control and color mixing on do very well, at the same time the consistency is also good, different batches can be done without color difference, excellent controllability makes the LED become a "high-tech pointed" technology, LED light-emitting diodes into a light source equipment in the "rich and handsome!
In addition, the LED light-emitting diode has become a light source equipment "high wealth".
In addition, the light-emitting diode is a cold light source, which directly converts electrical energy into light energy, which also explains what is called a cold light source, a cold light source is not infrared light source, is a low heat radiation light source, so that the LED light-emitting diode light is very high, unlike other light sources need to be converted into heat energy, most of the energy dissipation at the same time, but also send out a lot of infrared radiation can improve the surrounding temperature.