As an emerging green lighting source, semiconductor lighting is gradually entering various fields of people's lives. Transportation lighting has become an important application market for LEDs as lighting sources. At present, LEDs have been applied to the interior and exterior of automobiles, especially in automotive interior lighting. The application of color LEDs is very mature, for example, for instrument panels, backlight switches, automobiles. Reading lights or head-up display systems, or the use of the "Color-on-Demand" feature in the car, allows automakers to differentiate themselves from other competitors by using their own unique recognition colors. Or use color to distinguish between different series of products.
The history of LED car lights
The development of LED automotive lights is directly related to the development of LED light sources. The phenomenon of semiconductor electroluminescence was discovered in 1907. Due to the weak light, mass production is difficult and progress is slow. In 1968, Monsanto Company of the United States launched a red LED with a GaAsp/GaAs structure with a light intensity exceeding 20mcd, which was used as a breakthrough point and greatly accelerated the development of LED. Then, red, yellow and green LEDs with a light intensity of 1000mcd were successively developed, and preliminary applications were obtained on the signal indications of instruments and telecommunications, forming an early application market for LEDs. However, due to its performance indicators such as light intensity and light attenuation, it has not been widely used in automotive lamps. Until 1990, HP and Toshiba of the United States introduced red and yellow high-brightness LEDs with an InGaAlP/GaAs structure with a light intensity of more than 1000mcd and 1993, Japan’s Nichia Corporation invented InGaN/Al2O3 blue and green high-brightness LEDs. And mass production paves the way for LED lighting of automotive light sources.
In 1985, LED car lights first appeared on passenger cars. In 1986, the use of LED high-position brake lights on Nissan 300zx cars marked the beginning of the era of LED car lamps. Internationally renowned automobile brands such as BMW, Cadillac, Buick, Volkswagen, Ford, Mercedes-Benz, Toyota, Mitsubishi, Mazda and Skoda have successively launched LED automotive lamps.
LED car lights are growing at a double-digit rate every year. In 2005, the output value reached 546 million US dollars, accounting for 14% of the world's LED applications. China first used LED high-position brake lights on the Shanghai Volkswagen Santana 2000 in 2000. China's LED car lamps are growing at an annual rate of 70%-80%, and the output value in 2006 exceeded 100 million yuan.