From the technical point of view, the main headlights of the car are two kinds of halogen and xenon lamps; of course, there are still a lot of start class cars equipped with cheaper ordinary incandescent lamps, but because their technology is too old and is facing the trend of elimination by the previous two, it is no longer introduced here.
The halogen lamp began to be applied to the body in 70s. Its luminous principle is very similar to that of the ordinary incandescent lamp, that is, through the spiral tungsten wire in the lamp, the luminescence is limited by the melting point of the tungsten filament. Generally speaking, to increase the brightness of halogen lamps, we should not only increase the resistance of tungsten wires, but also increase the melting point of tungsten wires. Because of the higher melting point of tungsten filament than ordinary incandescent lamp, the brightness of the halogen lamp is greater than that of the latter.
The English short for the xenon lamp is the HID gas discharge lamp, which was first applied to air transportation. But it is the last more than 10 years that the car was used in large quantities. It was developed by HeLa company in early 90s. The luminous principle of xenon lamp is completely different from that of halogen lamp and incandescent lamp introduced previously. Instead of the filament, it uses the high pressure positive and negative electricity to stimulate the xenon in the light bulb to react with the rare metal, and we usually see that the small glass ball in the xenon lamp tube is the source of the xenon lamp, filled with xenon and a small amount of rare gold. But xenon lamps are more expensive than ordinary halogen and incandescent lamps because of their high technology content.
The difference between the xenon lamp and the halogen lamp is as follows:
(1) xenon lamps are illuminated by high voltage arc discharge, so xenon lamps need extra electronic control starting devices outside the bulb, commonly known as stabilizers. Because a xenon lamp needs a starting voltage of 23 thousand volts, and the halogen lamp of the ordinary car needs only a 12 volt working voltage stabilizer as an independent component outside the bulb, it has an important impact on the reliability of the xenon lamp. In addition, the safety of the stabilizer as a high voltage appliance is also very important.
2. If only xenon bulbs are modified, but lamps and lanterns are not changed correspondingly, the ideal results will not be achieved. Because the xenon lamp depends on the arc, the shape of the arc itself is slightly curved, so the xenon lamp will be different in the design of the lamps compared to the neatly shaped filament of the halogen lamp. Because of the bending of the shape, the focus position of the original halogen lamp can not be completely adapted to the electric shock of the xenon lamp.
The xenon lamp has a long life, but because it is not working independently, the quality of the stabilizer is directly related to the life span of the whole system. The inferior stabilizer sold on the market not only can not guarantee the same life life with the xenon bulb, but also produces strong electromagnetic interference in the work, and affects the work of the radio in the car. The xenon bulb is rarely bad, but because it is filled with high pressure of 6 high pressure xenon and a certain amount of mercury and metal halide, if the explosion or leakage not only pollutes the environment, it may hurt people and hurt the car.
Why do many modified xenon lights look very eye - to - eye at night so that the driver can not see the road at all? The surface reflector used by the halogen lamp can be installed by the simple modification of the xenon lamp, but because of the change of focus, it is difficult to produce the clear light cut-off of the original halogen lamp. Line, part of the light scattered to the angle should not be lit. And some high-grade car xenon lights, lamps and lanterns based on the characteristics of xenon lamps are specially designed, although it looks bright but not feel the eye, not only to ensure high brightness, but also do not affect the normal driving of other drivers on the road.
Besides, because the luminance of the two light sources of the xenon and halogen lamps is different, the reflection mirror using the halogen lamp will make the light reflected by the xenon lamp produce a partial light. Local too strong light, on the one hand, may interfere with the driver to judge the road conditions, on the other hand, also because of the different position of the front and dark contrast in front of the road, the driver of the road to the normal judgment of the road.
In Europe, the xenon lamp is also required to be equipped with a large lamp cleaning device to prevent the dust and dirt on the lamp cover from scattering, and to affect the line of sight of the driver on the vehicle.