Head lamp
Automotive headlights are generally composed of three parts: light bulb, reflector and matching mirror (astigmatism mirror).
one bulb
The bulbs used in automobile headlights are incandescent bulbs, halogen tungsten bulbs, new high-brightness arc lamps and so on.
(1) Incandescent bulb: its filament is made of tungsten wire (tungsten has a high melting point and strong light). During manufacturing, in order to increase the service life of the bulb, the bulb is filled with an inert gas (nitrogen and its mixture of inert gases). This can reduce the evaporation of tungsten wire, increase the temperature of the filament, and enhance the luminous efficiency. The light from an incandescent bulb has a yellowish tinge.
(2) Tungsten halide lamp: Tungsten halide light bulb is inserted into the inert gas into a certain halide element (such as iodine, chlorine, fluorine, bromine, etc.), using the principle of tungsten halide recycling reaction, that is, the gaseous tungsten evaporating from the filament reacts with the halogen to produce a volatile tungsten halide, which diffuses to the high temperature area near the filament, and is decomposed by heat, so that the tungsten is returned to the filament. The released halogen continues to diffuse and participate in the next cycle reaction, so the cycle continues, thereby preventing the evaporation of tungsten and the blackening of the bulb. Tungsten halogen light bulb size is small, the bulb shell is made of quartz glass with high temperature resistance and high mechanical strength, under the same power, the brightness of tungsten halogen lamp is 1.5 times that of incandescent lamp, and the life is 2 to 3 times longer.
(3) New high-brightness arc lamp: This lamp has no traditional filament in the bulb. Instead, two electrodes are placed inside a quartz tube. The tube is filled with xenon and trace metals (or metal halides), and when there is enough arc voltage on the electrode (5000 ~ 12000V), the gas begins to ionize and conduct electricity. The gas atoms are in an excited state and begin to emit light due to the energy level transition of the electrons. After 0.1s, a small amount of mercury vapor is evaporated between the electrodes, and the power supply is immediately transferred to the mercury vapor arc discharge, and then transferred to the halide arc lamp after the temperature rises. After the light reaches the normal working temperature of the bulb, the power of maintaining the arc discharge is very low (about 35w), so 40% of the electric energy can be saved.
2. reflector
The role of the reflector is to maximize the polymerization of light emitted by the bulb into a strong beam to increase the irradiation distance.
The surface shape of the mirror is a rotating paraboloid, generally made of 0.6 ~ 0.8mm thin steel sheet stamping or made of glass, plastic. The inner surface is plated with silver, aluminum or chrome and then polished; The filament is located at the focal point of the mirror, and most of its light rays are reflected and shot out into the distance as parallel beams. The light bulb without a mirror can only illuminate a distance of about 6m, and the parallel beam reflected by the mirror can illuminate a distance of more than 100m. After the mirror, there is a small amount of scattered light, of which the upward is completely useless, and the lateral and lower light helps to illuminate the road surface and curb of 5 to 10m.
3. lens
Pantoscope, also known as astigmatic glass, is a combination of several special prisms and lenses, and the shape is generally circular and rectangular. The function of the matching mirror is to refract the parallel beam reflected by the mirror, so that the road in front of the car has a good and uniform lighting.
How to deal with water mist in car headlights?
Car headlights have water fog can be treated in this way: open the headlights to evaporate naturally, exposure to the sun, purge with high pressure water gun, replace the headlamp lamp shade, blow with a hair dryer, replace the headlamp seal, discharge dehumidifier, add cooling fan, replace the headlamp.
The cause of the failure of the headlight?
Reasons why headlights don't work may include:
lamp damaged : the lamp is a wearing part, long time use or bad road conditions may cause damage.
overheat or short circuit : overheat or short circuit of the wire may affect the current transmission and cause the headlights to fail to turn on.
relay or combination switch failure : Relay or combination switch failure can also cause headlights not to light.
blown fuse : blown fuse is a common cause, check and replace the fuse can solve the problem.
line open, short or broken : poor or loose line connection, joint is not in place will also lead to the headlight is not on.
voltage regulator failure : A voltage regulator failure can cause the voltage to be too high, which can cause the lamp to burn out.
low battery power : Low battery power will affect the normal operation of the headlights.
loose headlamp plug : regularly check the headlamp plug is firm, timely tightening can avoid such problems.
In order to solve these problems, the following measures can be taken:
Inspect the bulb for damage and replace it with a new one if necessary.
Check the wires for overheating or short circuits, and repair or replace them if necessary.
Check that relays and combination switches are working properly, and repair or replace them if necessary.
Check if the fuse is blown and replace the fuse if necessary.
Check the line for open, short or broken, and repair if necessary.
Check that the voltage regulator is working properly and repair or replace it if necessary.
Check whether the battery is fully charged, and charge or replace the battery if necessary.
Check that the headlamp plug is firm and tighten if necessary.
Through these steps, you can effectively diagnose and solve the problem of car headlights not on.
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