Leds flashlight is a light emitting diode as light source of a new type of lighting, power saving, durable, strong brightness, etc. This flashlight is often used in special areas, such as public security riot.
LED light-emitting principle
The LED light flashlight Light-emitting diodes (leds) by Ⅲ - Ⅳ compounds, such as GaAs (gallium arsenide), GaP (gallium phosphide), GaAsP made of semiconductor such as gallium arsenide (p), its core is the p-n junction. So it is usually I - N characteristics of p-n junction, which is the wizard, reverse blocking, the breakdown characteristic. In addition, under certain conditions, it also has a luminescence properties. Under the forward voltage, the electronic by N area into P area, hole by P area into N area. Part into the area of minority carrier (Jane) with majority carrier (children) composite and glow, as shown in figure 1.
Assume that light is in the P region, then injected electrons and the valence band hole composite and shine directly, or be luminous center after capture, hole composite luminescence again. In addition, this kind of light composite some electrons are not luminous center (the center between the conduction band, interface with near middle) capture, then with hole compound, every time the energy released is not big, could not form visible light. Amount of composite luminescence relative to the amount of light composite, the greater the proportion of light quantum efficiency is higher. Because the compound is glowing in the Jane diffusion zone, so the light only near the surface of p-n junction generated within a few microns.
Theory and practice has proved that peak wavelength lambda light with the light emitting area of semiconductor materials forbidden band width of Eg, namely
???? Lambda material 1240 / Eg (mm)
Type of Eg unit for electron volts (eV). If you can produce visible light wavelength (780 nm to 380 nm violet light red light), Eg of semiconductor materials should be between 3.26 ~ 1.63 eV. Long wavelength than red light for infrared light. Now has the infrared, red, yellow, green and blue leds, but the blue light diode costs, the price is very high, use is not widespread.
The characteristics of the LED
1. The meaning of the limit parameters
(1) allow power Pm: allow LED on both ends are dc voltage and current flow through the maximum value of product. More than this value, LED fever, damage.
(2) the biggest positive dc current IFm: allow the biggest positive direct current. More than this value can damage the diodes. ??
(3) the largest reverse voltage VRm: the biggest reverse voltage is allowed to add. More than this value, light emitting diode can be broken down. ? ?
(4) work environment topm: light-emitting diodes (leds) working environment temperature range. Below or above this temperature range, the leds will not work properly, the efficiency is greatly reduced.
High energy saving, energy saving energy is the environmental protection from pollution. Dc drive, ultra-low power consumption (0.03-0.06 watts single pipe) electric power conversion is close to 100%, the same lighting effect than the traditional light source, energy saving more than 80%.
Long life: LED light source has called it longevity light, meaning never extinguished the lights. Solid cold light source, the epoxy resin encapsulation, no loose parts in the body, there is no filament light easy to burn and thermal deposition, droop, such as faults, service life can reach 60000 to 60000 hours, long service life 10 times more than traditional light.
Many changes: LED light source available principle of three primary colors red, green, and blue, in under the control of computer technology make the three colors gray level 256 and arbitrary mixed, can produce 256 * 256 * 256 = 16777216 kinds of color, form different combinations of light color changing, realize the dynamic change of rich and colorful effects and all kinds of images.
The environmental protection, environmental protection benefit is better, no ultraviolet and infrared spectrum, no heat, no radiation, glare small, and waste recycling, no pollution contains no mercury elements, cold light source, can safely touch, belongs to typical green lighting source.
High tip: compared with the traditional monotonous lighting effects, the LED light source is low pressure microelectronics products, successfully combines computer technology, network communication technology, image processing technology, embedded control technology, etc., so also is the digital information technology products, is a semiconductor photoelectric device "high point" technology, the online programming, unlimited upgrade, the characteristics of flexible.
Leds flashlight is a light emitting diode as light source of a new type of lighting, it has the advantages of power saving, durable, strong brightness. Choose a good LED light flashlight should pay attention to the points:
1, capita moderate. Household generally not more than 12 head, the battery used in 2 ~ 3 day as well, again big a little wave, for other special needs according to the need to make sure.
2, welding to prison. Each diode is through welded connection on the circuit board, if there is a virtual welding contact is bad, it is possible to buld not bright or impact to use as a whole.
3, buld condenser surface concentration as far as possible. This flashlight is not like a normal flashlight can adjust the focal length, do not have astigmatism phenomenon should be paid attention to when the choose and buy.
4, the power switch contact significantly. This flashlight with rotary switch, tighten it, loosen it again, if the contact is not obvious, it is easy to cause on the phenomenon.
5, pay attention to waterproof. Because it belongs to the electronic products, there is a circuit board, the front of a torch once water prone to short circuit, damage.