We all know that there are three main types of mainstream car headlight sources on the market: halogen headlights, xenon headlights and LED headlights. These three types of car lights have their own characteristics. When upgrading the car lights, professionals usually go through The original car lights have been upgraded and modified. Today we will analyze it from the perspective of car lights. Why should we upgrade the car lights?
1. Halogen headlights
The light-emitting principle of halogen headlights is the same as that of incandescent lamps. Because incandescent lamps emit tungsten filaments at high temperatures, they have a disadvantage. At high temperatures, they will accelerate the sublimation of tungsten, causing the filaments to gradually become thinner, and eventually the smaller localized heat will accumulate. , causing the filament to fuse. In order to slow down the process of filament melting, halogen tungsten lamps appeared. The earliest ones were iodine tungsten lamps, and later bromine tungsten lamps. We also call these lamps halogen lamps. These headlights fill the bulb with iodine vapor and bromine. Steam and other halogen methods are used to extend the life of the bulb.
Under appropriate temperature conditions, the tungsten evaporated from the filament reacts with halogen substances in the bubble wall area to form volatile tungsten halogen compounds. Because the bulb wall temperature is high enough (250°C), the tungsten halogen compound is in a gaseous state. When the tungsten halogen compound diffuses into the hotter area around the filament, it is differentiated into halogen and tungsten. The released tungsten is partially returned to the filament, while the halogen continues to participate in the recycling process.
Because the bulb wall temperature is high, the bulb wall of halogen headlights is made of quartz glass, and the volume of the bulb cannot be made larger in order to reach the reaction temperature. The high-temperature bulb wall is easily damaged by grease and other substances stained by uneven temperatures, so when installing halogen headlights, try not to touch the glass part of the bulb with your hands.
2. Xenon headlights
Xenon headlights are headlights made using the principle of gas discharge. By filling a variety of chemical gases, such as xenon and other inert gases, into a UV-resistant crystal quartz glass tube, the vehicle's 12-volt power supply is instantly increased to 23,000 volts through a supercharger. Under the high voltage, the xenon gas will be ionized and in the power supply A light source is generated between the two poles. The performance of xenon lamps has been significantly improved compared to halogen lamps, and their lifespan has also been significantly extended. However, gas discharge headlights require a process of boosting voltage, ionization, and lighting, so the startup speed is relatively slow.
3. LED headlights
LED is a type of semiconductor diode that can convert electrical energy into light energy. Like ordinary diodes, light-emitting diodes are composed of a PN junction and also have unidirectional conductivity. When a forward voltage is applied to the light-emitting diode, the holes injected from the P region to the N region and the electrons injected from the N region to the P region interact with the electrons in the N region and the holes in the P region respectively within a few microns near the PN junction. holes recombine, producing spontaneously emitted fluorescence. The luminous efficiency of LEDs is higher than that of gas discharge headlights. But usually the wavelength is short and the color temperature is high.
The photoelectric conversion efficiency of halogen headlights, xenon headlights and LED headlights are very different. According to data, the efficiencies are 20LM/W, 40LM/W and 100LM/W respectively. The most efficient LED headlights are even higher than halogen headlights. More than five times the amount. In addition, xenon headlights that use lenses can easily cause aging cracks in small areas of the transparent plastic shade of the headlights after long-term use due to the lens focusing heat radiation (such as the Audi Q5).
4. Car reflective cup
There are nothing more than the above three types of light sources. There are many names on the market, but they remain the same. If the above three light sources cannot satisfy you, you need to start from other places, such as lenses.
Most traditional headlights have the structure of a reflector cup (a reflector cup refers to a reflector that uses a point light source bulb as a light source and requires long-distance spotlighting. It is usually cup-shaped, commonly known as a reflector cup). The light source is mainly reflected toward the head through this reflector cup. Before forming the speed of light, reflective cups are divided into: plastic reflective cups, metal reflective cups, and glass reflective cups. The quality of the reflector directly determines the quality of the headlight effect. Currently, most of the metal reflectors used on the market are metal reflectors. Glass reflectors should be on high-end cars. It is a one-time stripping process, has high optical precision, no deformation memory, and is temperature-resistant. The disadvantages are high cost, fragility, and heavy weight.
5. Automotive lenses
Among automobile lights, the light shape of the lens head is the most standard. It can have obvious light and dark cutting lines, which solves the problem of astigmatism. In foreign countries, xenon lamps are used as standard lenses. This kind of mirror belongs to the optical mirror category. Class, we call it "lens". Compared with headlights using traditional lamp holders, headlights with lens-type lamp holders have the advantages of uniform brightness, strong penetration, and small light loss.
There are two types of lens lamp heads equipped on vehicles: single light and double light. The single-focal lens is designed with lenses corresponding to low-beam and high-beam respectively, such as: M6 low-beam lens, Mondeo high-beam lens; the difference between bifocal lenses is that it can perform transformations similar to far-beam and low-beam conversion. Normally, it is in the low beam state. When the high beam is turned on at the same time, it operates the dimming plate through the electromagnetic mechanism, so that the light of the low beam is also distributed to the high beam, which is equivalent to two high beams lighting up together. Bifocal lenses are generally used in mid-to-high-end cars, such as A6. BMW. Mercedes Benz etc.
6. Why do car lights need to be upgraded?
Car lights are one of the important configurations in the car's active safety system and are also an important tool for drivers to prevent traffic accidents. According to incomplete statistics, 60% of traffic accidents occur at night, and 22% of traffic accidents occur when the driver's vision is unclear. Higher brightness lighting can allow drivers to see potential accident hazards in advance and nip them in the bud. .
Headlights are not only a lighting system, they must provide drivers with an effective light so that they can see the condition of our roads, pedestrians, and road signs. In addition, they must also consider that they must avoid light projection. It causes glare in the eyes of other drivers. Upgrading the car lights can effectively improve these phenomena and ensure the driver's travel safety.
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