2024年4月9日发(作者：)

First LED Summary

一 LED概述

LED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices,

which can be directly converted into electricity to light. LED is the heart of a semiconductor chip,

the chip is attached to one end of a stent, is the negative side, the other end of the power of the

cathode, the entire chip package to be epoxy resin. Semiconductor chip is composed of two parts,

part of the P-type semiconductor, it inside the hole-dominated, the other side is the N-type

semiconductor, here is mainly electronic. But linking the two semiconductors, among them the

formation of a "PN junction." When the current through the wires role in this chip, will be pushing

e-P, P zone in the hole with electronic composite, and then to be issued in the form of photon

energy, and this is the principle of LED luminescence. The wavelength of light that is the color of

light, is formed by the PN junction of the decisions of the material.

LED（Light Emitting Diode），发光二极管，是一种固态的半导体器件，它可以直接把

电转化为光。LED的心脏是一个半导体的晶片，晶片的一端附在一个支架上，一端是负极，

另一端连接电源的正极，使整个晶片被环氧树脂封装起来。半导体晶片由两部分组成，一部

分是P型半导体，在它里面空穴占主导地位，另一端是N型半导体，在这边主要是电子。

但这两种半导体连接起来的时候，它们之间就形成一个“P-N结”。当电流通过导线作用于这

个晶片的时候，电子就会被推向P区，在P区里电子跟空穴复合，然后就会以光子的形式

发出能量，这就是LED发光的原理。而光的波长也就是光的颜色，是由形成P-N结的材料

决定的。

Second LED history and development

50 years ago, people have to understand semiconductor materials can produce

light of the basic knowledge, the first commercial diodes in 1960. English is the LED

light emitting diode (LED) acronym, and its basic structure is an electroluminescent

semiconductor materials, placed in a wire rack, then sealed with epoxy resin around,

that is, solid package, Therefore, the protection of the internal batteries can play the

role of line, so the seismic performance LED good.

LED is the core of the P-type semiconductor and components of the N-type

semiconductor chips, the P-type semiconductor and N-type semiconductor between a

transition layer, called the PN junction. In some semiconductor materials in the PN

junction, the injection of a small number of carrier-carrier and the majority of the

extra time will be in the form of light energy to release, thus the power to direct

conversion of solar energy. PN junction on reverse voltage, a few hard-carrier

injection, it is not luminous. This use of injection electroluminescent diodes is

produced by the principle of light-emitting diodes, commonly known as LED. When

it in a positive state of the work (that is, at both ends with forward voltage), the

current flows from the LED anode, cathode, semiconductor crystals on the issue from

the ultraviolet to infrared light of different colors, light and the strength of the

currents.

Instruments used for the first LED light source instructions, but all kinds of

light colored LED lights in traffic and large screen has been widely applied, have a

very good economic and social benefits. The 12-inch red traffic lights as an example,

is used in the United States have long life, low-efficiency 140 watt

incandescent lamp as a light source, it produced 2,000 lumens of white light. The red

filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design,

Lumileds companies have 18 red LED light source, including the loss of circuit, a

total power consumption of 14 watts to generate the same optical effect. Automotive

LED lights is also the source of important areas.

For general lighting, people need more white light sources. The 1998 white

LED successful development. This is the GaN LED chip and Yttrium Aluminum

Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd =

30nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by

this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the

LED-based Wanxing reflection in the cavity, covered with a resin mixed with YAG

thin layer, about 200-500 nm. LED-based tablets issued by the Blu-ray absorption part

of the phosphor, the phosphor another part of the Blu-ray and a yellow light mixed,

can be a white. Now, the InGaN / YAG white LED, YAG phosphor by changing the

chemical composition of the phosphor layer and adjust the thickness of the

3500-10000 K color temperature can be colored white. This blue LED through the

method by white, constructed simple, low-cost, high technology is mature, so use the

most.

The development of LED display can be divided into the following phases:

first phase 1990 to 1995, mainly monochrome and 16 color graphics screen. Used to

display text and simple images, mainly used in railway stations, financial securities,

banks, post offices and other public places, as public information display tools. The

second stage is from 1995 to 1999, there have been 64, 256 level gray-scale two-color

video screen. Video control technology, image processing, optical fiber

communication technology applications will enhance the LED display to a new level.

LED display control LSI chips special at this time developed by domestic companies,

and can be applied. The third stage, from 1999, red, pure green, blue LED in bulk into

China, while domestic enterprises in-depth research and development work, using red,

green, and blue LED production of full-color display has been widely used , poured

into sports stadiums, convention centers, squares and other public places, which will

bring the domestic large-screen full-color era. With the rapid development of LED

materials market, surface mount device is available from 2001, mainly used in indoor

full color, and its high brightness, colorful, low temperature characteristics, the point

spacing can be adjusted by different price Requirements were accepted, in just two

years time, product sales have more than 300 million yuan, surface mount full-color

LED display application market entered the new century. To meet the 2008 Olympic