The evolution of automotive lighting occurs with the replacement of automotive light sources, and generally goes through the following four stages:
The first generation of automotive light sources were directly burned and emitted by fuel (candles, kerosene, or acetylene), which could meet the requirements of early car lights. However, they had obvious drawbacks such as low luminous efficiency, weak light intensity, unstable performance, and complex operation.
The second generation of car light sources are incandescent lamps. In 1879, Edison invented the incandescent lamp. In 1913, the United States was the first to apply incandescent lamp technology to Cadillac car headlights, revolutionizing car lighting and ushering in the electrical age. Subsequently, new technologies such as car mirrors, starters, generators, and batteries emerged, and in 1925, cars truly entered the era of incandescent automotive lighting. In the 1950s, tungsten halogen lamps emerged again and quickly became the main light bulb for strong light sources in automobiles.
The third generation of automotive light sources is gas discharge lamps (HID). It has the advantages of high luminous efficiency, high brightness, and high reliability, and will replace incandescent lamps and halogen tungsten lamps as the new type of light source for automotive headlights.
The fourth generation of automotive light sources is semiconductor light-emitting diodes (LEDs). LED is a semiconductor PN junction diode. When a forward bias is applied to both ends of the PN junction, the PN junction system is excited, and the carriers transition from low energy to high energy. When unstable carriers in high energy return to low energy and recombine, according to the principle of energy conservation, the excess energy will be released in the form of photons, which is the principle of LED electroluminescence.
In terms of the current development status and trend of LED car lighting technology, LED high mounted brake lights will be further popularized in China, with prices steadily decreasing. LED rear brake lights, turn signals, and fog lights will begin to be commercialized, and LED car lighting will develop towards personalization and artistry. At the same time, LED intelligent control systems will also develop rapidly.