With the development of automobile science and technology, the types of automobile headlights are constantly improved. Halogen headlamp, xenon headlamp, LED headlamp and laser headlamp have appeared successively, which have been applied in different vehicle models. Different types of headlamp sources have their own advantages and disadvantages. So, which of these kinds of headlights is the best light source?
Before discussing this problem, let's first introduce these kinds of headlights.
1、 Halogen headlamp
Halogen headlamp can be said to be the most common light source type of automobile headlight among all kinds of automobiles of major automobile manufacturers, and its history can be traced back to the 1970s. Halogen headlamp is actually an improved incandescent lamp. Halogen gas is added into the incandescent bulb. Adding halogen gas can make the halogen bulb more durable than the incandescent bulb. Because the direction of halogen bulb is omni-directional, it belongs to astigmatism light source. People use reflector to gather light, so we usually use halogen lamp as light source and gather light through reflector The lamp group is called reflective halogen lamp. When we observe the traffic on the road at night, nine out of ten of the Yellow headlights are models equipped with halogen headlamps. From the perspective of effect, the color temperature of halogen headlamp is low, so the light color is warm and yellow. In the case of dark light, yellow halogen lamp is not as conspicuous as xenon lamp, but there is no problem to meet the normal use at night. The biggest advantage of halogen lamp lies in its strong penetrability. In the case of fog, heavy rain and low visibility, the penetration ability of halogen lamp light source is far higher than that of other products with high color temperature.
2、 Xenon headlamp
Xenon lamp uses the arc generated by the discharge device between two electrodes to emit light, just like the arc light produced in welding. High voltage pulse electricity is applied between the metal electrodes in the sealed miniature quartz bulb, which excites the substances in the bulb (xenon, a small amount of mercury vapor, metal halide) to ionize in the arc to produce light. The color temperature of this light is similar to that of sunlight, but it contains more green and blue components, so it presents blue white light. This blue and white light greatly enhances the brightness of road signs and signs. The luminous flux emitted by xenon lamp is more than twice that of halogen lamp. At the same time, the efficiency of converting electric energy into light energy is 80% higher than that of halogen lamp. Therefore, xenon lamp has relatively high energy density and light intensity, and its operating current is only half of that of halogen lamp.
But in the rain, snow, fog and other weather conditions, the penetration is not as good as halogen lamp, and the circuit is complex and expensive.
3、 LED headlamp
Strictly speaking, LED headlight has no bulb, but uses a semiconductor chip similar to circuit board as light source. Then use the reflector or lens to focus the light to achieve the lighting effect. LED can directly convert electrical energy into visible light, the conversion efficiency is very high. Many luxury brands use full LED as the source of headlight. But the LED light source for the cooling and ventilation requirements are also very high, because of the heat is relatively large, the general LED headlight has a cooling fan behind.
The energy consumption of LED light source is only 1 / 20 of that of halogen lamp, and its service life can reach more than 100000 hours. Basically, the lamp can be used normally after being driven to scrap. Compared with xenon headlamp, the LED light source has smaller volume and can be turned on instantaneously, which is very safe for driving.
4、 Laser headlamp
The light-emitting element of laser headlamp is laser diode, which has many similarities with LED light-emitting diode. The irradiation range can reach 600 meters at most. At present, only Rolls Royce and Audi use laser headlamp in their high-end models. At the same time, the disadvantages are very obvious, that is, the cost is too expensive, the general car model with laser headlight, it is really "buy headlight to send car"; in addition, the laser headlamp generally needs to be used together with LED headlamp, because although the laser headlamp has a long irradiation distance and is bright, but its illumination range is narrow, it needs LED headlamp to supplement light.