1. What is LED?
LED is the abbreviation of the English word Light Emitting Diode, the Chinese name for the light-emitting diode, is a way to convert electrical energy directly into visible light semiconductor devices. (Structure shown below)
The heart of the LED, the LED chip is shown above, the one end of the LED chip attached to a bracket, one end of the negative electrode, the other end connected to the positive power supply, so that the whole wafer is epoxy encapsulated.
LED chips composed of two parts, the part of the P-type semiconductor, the hole in it dominant, the other end is an N-type semiconductor, in the side of the main electronics. But the two semiconductor linking between them to form a "PN junction. When the current through the wire to the LED chip, the electrons will be pushed to the P region, the P zone electron hole recombination, then will be issued in the form of photons of energy, which is the principle of LED luminous.
2. Several concepts forLED
1, the luminous flux (lm): Because the human eye to different wavelengths of electromagnetic waves having different sensitivity, we can not directly radiated power or radiation flux of the light source used to measure the light energy must be used as a reference on the amount of sense of the human eye to lightunits ---- luminous flux to measure. Luminous flux notation Φ lumens (lm).
2, Luminous intensity (cd): the luminous flux is the total light energy emitted by a light source to the surrounding space. The luminous flux emitted by the different light source distribution in the space is different. The emission intensity in units of candela, the symbol for cd, it indicates that the light source in a unit steradian solid angle (the angle formed by the surface of the object to the point light source) within the light flux emitted. 1 cd = 1 lm / 1 sr (sr: solid angle steradian units).
3, brightness (cd/m2): brightness is that the eyes see the object the intensity of light emitted from a certain direction. Units of candela / square meter [cd/m2], symbol L, indicating that the light flux of the luminous body in a specific direction per unit solid angle per unit area, which is equal to one square meter surface issued on the luminous intensity of 1 candela.
4, the color temperature (Color Temperature): When the color of the light emitted by the light source and the blackbody radiation color at a certain temperature is the same, the temperature of the blackbody is called the color temperature of the light source, with the absolute temperature K (Kelvin, Kelvin degrees = degrees Celsius + 273.15).
3. LED advantages:
1, small size
LED is basically a small chip is encapsulated in epoxy resin inside, so it is very small and very light.
2, low power consumption
LED power consumption is very low, DC drive, ultra-low power consumption (single tube 0.03-0.06 W) electro-optical power conversion close to 30%. General, LED's operating voltage is 2-3.6V, operating current is 0.02-0.03A; This means that the electrical energy it consumes no more than 0.1W, nearly 80% of the same lighting effects than traditional energy sources.
3, long life
Called LED light source for long life lamps. Solid cold light source, epoxy resin, light body and no loose parts, there is no filament light easy to burn, heat deposition, the light fades and other shortcomings in the right current and voltage, the service life of up to 60000-10 million hours, more than 10 times longer than traditional light source life.
4, high brightness, low heat
LED cold light technology, much lower heat than conventional lighting.
5, environmental protection
LED is made from non-toxic materials, unlike fluorescent lamps containing mercury can cause pollution, while LED can also be recycled. No ultraviolet and infrared spectra, neither heat nor radiation, glare small, cold light source, safe touch, typical of green lighting
LED is completely encapsulated in epoxy resin inside than light bulbs and fluorescent tubes are sturdy. Light body and no loose parts, so that the LED is not easy to damage.
7, more changes
LED light source can make use of red, green, and blue color theory, under the control of computer technology to make three colors with 256 gray scale, and any mix can produce a 256 × 256 × 256 = 16777216 colors to form a different light color combination dynamic and to achieve a variety of dynamic change effects and a variety of images.
LED灯 beads Red Green Blue Three primary colors
8, advanced technology
Compared to the monotonous glow of traditional light sources, LED lighting is low voltage microelectronic products. Successful integration of computer technology, network communication technology, image processing technology, embedded control technology, so it is also a digital information products, semiconductor optoelectronic devices, "high point" technology, with online programming, unlimited upgrades, flexible characteristics.
4. LED Category
1, according to the light-emitting color can be divided into red, orange, white, purple, green (yellow and green, standard green and pure green), blue and so on;
2, press out the the glossy feature cyclotomic lights, side lights, rectangular surface emitting tube, lateral tube;
3 package structure points to epoxy encapsulation, metal base epoxy package, ceramic base epoxy packaging and glass packaging;
4, according to the luminous intensity divided ordinary brightness (luminous intensity is smaller than 10mcd), high brightness (luminous intensity greater than 100mcd) and high-brightness (luminous intensity in the 10-100 MCD);
5. Commonly used chip LED display, luminous colors and corresponding wavelength range
Red (RED): R (610nm-640nm);
Green (GREEN): G (520nm-525nm);
Blue (BLUE): B (465nm-470nm).
6. LED applications
1, landscape lighting market: architectural decoration, interior decoration, attractions decorative, mainly used for the important decorative lighting of buildings, streets, commercial center, monuments, bridges, community, patio, lawn, home, leisure and entertainment, as well asset decoration and advertising is one of the commercial lighting.
2 auto market: car market is LED use the fastest-growing market, mainly for the car dashboard, air conditioning, stereo, lights and internal reading lights the exterior third brake lights, tail lights, turn signals, side lights and so on.
3, backlight market: LED as a backlight has generally been used in mobile phones, computers, handheld handheld electronic products and automobiles, aircraft instrument panel and many other fields.
4, traffic lights market: As the red, yellow and green LED high brightness, long life, energy saving and other advantages, a substantial increase in demand for the market at the traffic lights.
5, indoor and outdoor large-screen display: red, green, and blue primary colors of light due to the high brightness LED can produce full-color, LED large screen display in finance, securities, transportation, airports, telecommunications and other areas of the acclaimed; nearly two years of full color LED display instead of the traditional light boxes, neon, magnetic flap into the mainstream, especially in large stadiums around the world have become almost a standard feature.
6, Special lighting and military use: the LED light source has the characteristics of earthquake resistance, weather resistance, good sealing, and low thermal radiation, small size, easy to carry, can be widely used in explosion-proof, field operations, mining, military action special workplace or poor working environment.
7: LED can also be used in toys, gifts, flashlights, Christmas lights and other light industrial products, and China, as an important production base of light industrial products in the world, has a huge market demand for the LED.