Before the characteristics and classification of LED, let us first look at the concept of LED, the so-called LED is the abbreviation of Diode Emitting Light English Chinese, meaning that the light emitting diode, it is capable of converting electrical energy into visible light of the semiconductor device, the device is usually in the form of solid state. The core of LED is the semiconductor wafer, which is mainly composed of two parts: P semiconductor and N semiconductor.
The main features of LED
Because LED uses the principle of electric field luminescence, its characteristic is very obvious:
(1) long service life. General LED service life can reach 10 years. This is because LED is different from the traditional light source, it will not happen suddenly does not work or is the same as suddenly burn incandescent light, its damage is mainly associated with the passage of time and the resulting luminescence properties gradually weaken.
(2) low maintenance costs. Under normal circumstances, compared with ordinary light source, the service life of LED is equivalent to more than 10 times, so that the cost of replacing the light source is greatly reduced.
(3) low energy consumption. Compared with fluorescent lamp or incandescent lamp, the luminous efficiency of LED is much higher.
(4) small volume. This feature is mainly for the LED chip. At this stage, the minimum size of the LED chip can reach millimeter.
(5) strong directivity. On the light of the distance, LED can be used as a point light source design. Generally in the optical design, in order to simplify the design process will be used to split the light source into a number of point light source, these light sources can be replaced by LED. At the same time, LED can also be distributed on the surface of an object, and simulate the shape of the object to light, such as landscape lighting, architectural lighting, etc..
(6) solid state lighting, green environmental protection. LED is a solid state lighting source, which does not contain broken glass material, high impact and shock resistance, it can be used in a more harsh environment. At the same time, LED does not contain mercury and other toxic and harmful substances, a high degree of environmental friendly. In addition, LED also does not contain infrared or ultraviolet light, will not harm the irradiated object, but also effectively improve the utilization of light energy.
(7) low working voltage, suitable for working under low temperature. The main working mode of LED is low voltage DC power supply, which makes the safety of the system fully embodied. At the same time, it can work under the condition of low temperature, the experiment proved to be able to work under the conditions of -40 degrees Celsius, based on this point, it can be used in the refrigerator lighting system and automotive lighting system.
At present, due to the LED has a very good market prospects, so LED manufacturers are more and more, China's LED classification is no uniform standard. Under normal circumstances, according to the chip power, color and wavelength classification.
(1) chip power. According to the size of the power of the LED chip can be divided into the following types: the output power of a few dozen mW single lamp, that is, small power chip; power LED. Generally refers to the input power is less than 1W LED; high power LED. Specifically refers to the input power was 1W LED.
(2) luminous color and wavelength. Different wavelengths determine different colors of light. According to the wavelength of LED can be divided into infrared receiver tube and reflection tube and the wavelength is shorter than 390nm UV LED.
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