1.The origin of
In the 1960s, scientists developed LED light emitting diodes using the principle of semiconductor PN junction luminescence. At that time the development of LED, the material used is GaASP, its luminous color is red. After nearly 30 years of development, the familiar LED has been able to emit red, orange, yellow, green, blue and other colors. However, the white LED for lighting was developed only after 2000. Here we introduce the white LED for lighting.
The development of
The LED light source made of semiconductor p-n junction luminescence principle first appeared in the early 1960s. The material used at the time is GaAsP, glowing red (lambda p=650nm) with a luminous flux of only a few thousandths of a lumen at a driving current of 20 ma, with a corresponding optical efficiency of about 0.1 lumen/watt.
In the mid-1970s, the introduction of In and N LED to green light (lambda p=555nm), yellow light (lambda p=590nm) and orange light (lambda p=610nm), and the optical efficiency was also improved to 1 lumen/watt.
By the early 1980s, GaAlAs's LED light sources emerged, bringing the optical vision of red leds to 10 lumens per watt.
In the early 1990s, the development of two new materials, GaAlInP with red light and yellow light, and GaInN with green light and blue light, resulted in substantial improvement in LED optical performance.
In 2000, the former LED had a light efficiency of 100 lumens per watt in the red and orange area (lambda p=615nm), while the latter LED had a light efficiency of 50 lumens per watt in the green area (lambda p=530nm).
-- 1879 Edison invented the electric light;
-- 1938 the advent of fluorescent lamps;
-- 1959 halogen lamps were introduced;
-- 1961 high pressure sodium lamp comes out;
-- 1962 metal halide lamp;
-- 1969 the first LED light (red);
-- 1976 green LED light;
-- 1993 blue LED light;
-- 1999 white LED light;
-- 2000 LED for indoor lighting.
The development of LED is the second revolution after the 120 years of white-hot lighting.
-- at the beginning of the 21st century, LED, which is developed through the wonderful encounter between nature, human and science, will become an innovation in the light world and an indispensable green technology light revolution for human beings.
The LED will be the next great light revolution since Edison invented the light bulb.
LED lighting is mainly dominated by high-power white LED single light, the world's top three LED lighting manufacturers warranty for three years, large particles per watt greater than or equal to 100 lumens, small particles per watt greater than or equal to 110 lumens. Light decay of large particles less than 3% per year, light decay of small particles less than 3% per year.
LED solar street lamps, LED projection lights, LED ceiling lights, LED fluorescent lights are ready for mass production. For example, a 10-watt LED fluorescent lamp can replace a 40-watt ordinary or energy-saving lamp.
More and more LED energy-saving lights have entered ordinary homes, but not yet popular!