Car lights Evolution

the evolution of automotive lighting has gone through the following four stages:

1.The first generation of the car is a fuel source ( candles, kerosene or acetylene ) direct combustion of light, it can meet the requirements of the early lights , but there is very low luminous efficiency,Light weak, unstable performance, complex operations and other obvious shortcomings.

2. The second -generation automotive light sources are incandescent . 1879 Thomas Edison invented the incandescent lamp, in 1913 the United States first incandescent technology in accordance with the former Cadillac Lights , auto lamps revolutionary change took place , from automotive lighting into the age of electricity. Then, the car has appeared mirrors, starter ,Generators and batteries and other new technologies in 1925, the car began to truly enter the era of automotive lighting incandescent . 1950s appeared tungsten halogen lamp , it is very Fast become a major automotive bulb strong light source.

3. The third generation car is a gas discharge lamp light source (HID). It has a high luminous efficiency, high brightness and high reliability , etc., will replace incandescent, halogen into vehicle headlamp as a  new source .

4. The fourth generation of automotive light sources are light emitting diodes (LED). LED is a semiconductor PN junction diode , when a forward bias is applied to both ends of the PN junction , so that When the PN junction systems are excited carriers by the high-energy state to a lower energy state transitions , high-energy state is unstable when the carrier back to a lower energy state complex , according to the energy Conservation principle amount , the excess energy will be released in the form of photons , it is the LED electroluminescent principle .