1803~2014, LED lamp Chronicles

LED (full name: Light-Emitting Diode, LED) is a light-emitting semiconductor electronic components. The early electronic components only emit low luminosity red light, after the development of other monochromatic version to emit light today in visible light, infrared and ultraviolet spectrophotometry, also increased to a luminosity. With the development of technology, LED has been widely used in the field of display, TV lighting decoration and lighting. Driven by market demand and technological progress, LED has experienced a glorious history. Here, LEDinside Xiaobian with you to review the development process of LED.

In 1907, the Henry Joseph Round found that the silicon carbide crystal (SiC) as the abrasive can be energized after the phenomenon of electricity. After the discovery of this phenomenon, the study of the luminescence of minerals in SiC and II - group compound semiconductors has been carried out. In 1936, George Destiau published a report on the future luminescence of zinc sulfide powder. With the deepening of the research, the term "electroluminescence" was finally found. In 1952, the artificial synthesis of Ge, Si crystal luminescence of the birth of pn. In 1954, the properties of GaP single crystal and GaAs single crystal were studied. In 1955, Lubin (Radio Corporation of) of the Radio Corporation America America (Rubin Braunstein) for the first time discovered the gallium arsenide (GaAs) and other semiconductor alloy infrared radiation effect. In 1962, GE, Monsanto, IBM joint laboratory developed a red phosphorus gallium arsenide (GaAsP) semiconductor compound, which can be seen from the development of light-emitting diodes into the commercialization process. 1965, the world's first commercial light-emitting diode two was born, it is made of germanium material can be issued infrared LED, when the price is about $45. Shortly thereafter, Monsanto and Hewlett-Packard Co introduced the use of GaAsp materials made of commercial red LED. The efficiency of this kind of LED is about 0.1 lm/w, which is less than 100 times of that of the general 60-100w white woven lamp at 15 lm/w. In 1968, LED's research and development has made a breakthrough, the use of nitrogen doping process makes the efficiency of GaAsP devices up to 1 lm/w, and can emit red, orange and yellow light. 1971, the industry has launched a GaP chip with the same efficiency LED. In 1993, Japan's Nichia chemical (Nichia) work of Nakamura Shuji successfully put nitrogen infiltration, the invention of the wide band gap semiconductor materials based on gallium nitride (GaN) and gallium indium nitride (InGaN) has commercial value of blue LED, this kind of LED is widely used in the late 1990s. In 1997, Schlotter and Nakamura et al. Have invented the technology of encapsulating white LED with blue tube core and yellow light phosphor.

Following the GaN LED, the scientific community and then produce a high intensity of green and blue light can be generated in the LED. The ultra bright blue chip is the core of the white LED, which is coated with fluorescent powder, and then converted into white light by absorbing the blue light from the chip. Use this technique to create any visible light. In 2001, Kafmann et al. Used UV LED to excite three primary phosphor to obtain white LED. In 2002, the market began to have a 5W of LED, and its efficiency is about 18 to 22 lumens per watt. In September 2003, CREE Inc. company demonstrated its new Blu ray LED, 20mW in the effect rate of 35%. They also produced a 65 lm/W (lumens per watt) of white LED products, which was the brightest white light on the market LED. In 2005 they showed a prototype of a white LED, in 350mW, a record of 70 LM per watt efficiency.

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