LED wash wall lamp and what is the difference between LED project-light lamp?
a variety of LED lights, LED light, LED lamp, LED lamp cup, LED energy-saving lamps, LED lights, LED buried lights, LED clearance light, LED project-light lamp50 years ago, LED the structure and the luminescent principle of people already know basic knowledge of the semiconductor materials can produce light, produced the first commercial diodes in 1960. LED is a light emitting diode, its basic structure is an electroluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, protect the internal core, so the LED seismic performance is good. Light-emitting diodes (leds) core part is composed of p-type and n-type semiconductor semiconductor chips, between the p-type and n-type semiconductor semiconductor has a transition layer, called p - N junction. In some of the semiconductor PN junction, the minority carrier injection with majority carrier compound will release excess energy in the form of light, so as to directly convert the electric energy to light energy. PN junction to add reverse voltage, minority carrier injection, so the light. Principle of the use of injection electroluminescent diode called light-emitting diodes (leds), known as the LED. When it is in a state of positive work ( The combined with forward voltage on both ends) , when the current is flowing from the LED anode to cathode, semiconductor crystal gives different colors of light from ultraviolet to infrared, the strength of the light associated with current. Second, the characteristics of the LED light source 1. LED voltage: use the low voltage power supply, power supply voltage in 6 - Between 24 v, and varies according to the product, so it is a safer than using high voltage power supply power supply, especially suitable for public places. 2. Efficiency: compared with incandescent lamp lighting energy consumption reduced by 80%. 3. Applicability: small, each unit of LED is 3 - dice 5 mm square, so can be prepared into various shapes of the device, and is suitable for variable environment. 4. Stability: 100000 hours, droop for 50% of the original. 5. Response time: its response time of millisecond incandescent lamps, LED lights response time in nanoseconds. 6. Mercury pollution to the environment: no harmful metal. 7. Color: change current can change color, leds conveniently by the methods of chemical modification, adjust the band structure and band gap, red yellow green blue orange polychromatic light. Such as small current when the red LED, with the increase of current, can in turn into orange, yellow, and finally for the green. 8. Price: the price of the LED relatively expensive, compared to incandescent lamp, the price of a few leds with the price is quite a incandescent lamp, and usually lights in each group should be composed of 300 ~ 500 on diode. Three monochromatic light LED, the type and development history of the earliest application of P - semiconductor N junction luminous principle of LED lights come out in the early 1960 s. When materials are used in the GaAsP, glowing red ( λp = 650海里) The flux, when the drive current to 20 ma, only a few lumens per thousand, corresponding luminous efficiency is about 0. 1 lumens per watt. In the mid - 70 - s, introducing elements In, and N, LED, produce green ( λp = 555海里) , yellow light, λp = 590海里) And orange light ( λp = 610海里) , photosynthetic efficiency and increase to 1 lumens/watt. GaAlAs appeared in the early 80 s, the LED light source, make the red LED lights up to 10 lumens per watt. In the early 90 s, the red light, yellow light GaAlInP and hair green, and blue lights GaInN successful development of the two kinds of new material to make the LED luminous efficiency are improved greatly. In 2000, the former made of LED in the red, orange, λp = 615海里) The photosynthetic efficiency of 100 lumens per watt, while the latter made of LED in the green area ( λp = 530海里) The photosynthetic efficiency can reach 50 lumens per watt. Four, monochromatic light LED application initially LED is used as the indicator light instrument and then all kinds of light color of LED traffic light and display screen has been widely applied in large area, produced good economic and social benefits. Car light is also an important field of LED light source. In 1987, our country began to install high in the automobile brake lights, LED fast response (because Nanosecond) , you can make following vehicle drivers know driving conditions, as early as possible to reduce car crash happened. In addition, the LED light in red, green, and blue full-color displays, outdoor key buckles type micro torches, and other fields have been applied. Five, the development of white LED for general lighting, people need more white light sources. Hair white light LED successful development in 1998. This LED to GaN chip and yttrium aluminum garnet ( 掺钕钇铝石榴石) Packaged together. GaN chip blu-ray ( λp = 465海里,Wd = 30海里) , high temperature sintering of Ce3 + YAG phosphors in the yellow light excited by blue light emission, peak of 550 nm. Blue LED substrate is installed in the bowl reflection cavity, covered with thin layer of resin mixed with YAG, about 200 - 500nm。 LED substrate from the blue part is absorbed phosphor to another part of the mix blue with yellow light from fluorescent powder, we can get more white light. Now, for InGaN/YAG white leds, by changing the chemical composition of YAG phosphors and adjust the thickness of phosphor layer, the 3500 - color temperature can be obtained A variety of white light 10000 k. 3 blue LED green LED red leds InGaN AlInGaP encapsulates three small pieces will send three primary colors together, constitute a multiple variety of white leds light color LED InGaN, GaP AlInGaP across the visible light region a variety of light chip packaging together, constitute a white LED lighting with LED light source, and the first replace the power-hungry incandescent lamp, then gradually into the lighting market, will save a lot of electricity. Recently, white leds have reached single power more than 1 watt, 25 lumen, light output also increased its usefulness.