Chai Guosheng Yang Zhengming
(Guangdong Snowlight Optoelectronics Technology Co., Ltd.)
Pick   To briefly before the lighting of the motor vehicle as well as the importance of safe driving requirements of modern vehicle headlights. Introduced the characteristics and characteristics of the new type of headlights, which are rapidly spreading, and the new structure designed by Guangdong Xuelaite Company to reduce the glare of such lamps.
The length of the halogen filament is 5.5mm, while the distance between the poles of the vehicle xenon metal halide lamp is 4.2mm. The illuminant is shorter than the halogen lamp and closer to the point source. The use of such a light source will simplify the luminaire design and provide higher light utilization.
Fig.1 Vehicle Xenon Metal Halide Lamp is a discharge lamp with no filament. The shell is filled with high-pressure helium, filled with mercury and metal halide in addition to a pair of electrodes. The structure is shown in Fig. 1. During operation, strong arc discharge occurs between the electrodes. The arc temperature is up to 6000K, and the wall temperature of the arc tube is about 1000°C. At this time, all the substances charged in the lamp, including mercury and various metal halides, are completely vaporized, and the metal halide molecules are near the high temperature arc. Dissociation into halogen and metal atoms such as mercury, sodium, cesium, krypton, xenon, indium, etc. and halogen atoms, in addition to mercury, the resonance potential of such metal element atoms is more than 1.9 ~ 3 electron volts, in other words, its resonant radiation Both are in the visible region. These atoms produce high efficiency visible radiation when excited in an arc, and their color temperature and color rendering index are easily controlled by adjusting the composition and ratio of the filled metal halide. It is precisely because a compound in which a plurality of rare earth or alkaline earth or alkali metal iodine or bromine is charged as a main luminescent material, such a lamp is called a metal halide lamp or a metal halide lamp. Generally, the starting gas charged in the metal halide lamp for illumination is low-pressure argon gas, and the metal halide lamp used as the light source of the automobile headlight is filled with high-pressure helium gas, so the most suitable name for the vehicle lamp is for the vehicle. Xenon metal halide lamp.
Key words Xenon metal halide lamp for vehicle, bulb type shell, glare, electronic ballast
I Introduction
In 1879, Edison invented the vacuum incandescent lamp that uses carbon wire as a radiator and uses electric energy as an energy source to shake the scientific and technological world. Subsequently, the tungsten filaments with longer life and easier processing were replaced by carbon filaments to make a practical tungsten incandescent bulb, thus ending the era of burning illumination that lasted for tens of thousands of years in the history of human civilization, creating a precedent for electrical lighting. . Today, electric lighting, one of the important symbols of human civilization, has given the humans half the time of light and is more colorful, brilliant and omnipresent, but it is so popular, cheap, and accessible. The scientific and technological achievements are so ordinary and no longer attract people's attention.
Later in the invention of the light bulb, another important scientific and technological achievement of human beings, one of the main pillars of the modern economy, entered the people's life. Like the electric light source, the appearance of the automobile essentially changed people's life, production and everything. activity. It is difficult to imagine what would happen in today's world if there is no electric lighting, no cars, people's lives, production and society as a whole.
Electrical lighting and cars seem to be two isolated inventions, but they are actually closely linked, complement each other, promote each other, and become the driving force for social development. The emergence of electric light sources provides an important basis for the development of automobiles, and it is impossible to imagine how cars without lights will travel. The development of the same car has put forward higher requirements for electric lighting, providing more opportunities for the development of electric lighting and new development areas - automotive lighting.
At the beginning of the car in 1886, when the old classic cars were slow and slow on narrow and rugged roads at less than 30 km/h, its quirky figure and movement, deafening noise, especially at night. The swaying suspended lights have caused great curiosity. At that time, due to the low speed and fewer vehicles, the deafening noise spread far and wide. There was no harm to the people, no risk of collision, and a flashlight was enough to illuminate its future and accompany it as a long night trip. But since then, vehicles and lights have been inextricably linked.
After the car was slightly popular, the model was slightly improved, and the speed of the car was improved, the bustling pedestrians on the road and the increasing number of vehicles no longer allowed the car to sway freely with a flashlight. At this time, the light source engineer immediately relied on the emerging tungsten incandescent lamp to design a pair of bright incandescent eyes for the car, enabling them to see the things in the way forward, so as to avoid the murder and ensure safety in time. Of course, at that time, the car engineers have equipped the car with the small-sized generators needed to start the car, which is the premise of the development of automotive electrical lighting.
In the situation of increasing number of vehicles and increasing speed, it is not enough to look ahead. It is also necessary to look around and avoid the worries. From now on, not only the headlights, various taillights such as driving lights, brake lights, turn signals, rear fog A series of lamps, such as lamps, have been invented one after another, in order to avoid the collision of night driving or the collision when turning. Then the headlights developed into a variety of lights such as low beam, high beam and front fog. More than ten different types of electrical lighting devices have been installed in the front, rear, side and interior of a modern vehicle.
The perfect lighting of the car not only provides convenience and comfort for the driver, but also provides safety guarantee for the driver and pedestrian. The perfect car lighting has greatly increased the speed of the car, which has increased the car capacity of the road, provided a wider space for the development of the car, and provided a more complete development foundation and conditions for the car lighting industry.
In order to improve the operating temperature and luminous efficiency of the filament without reducing the life of the incandescent lamp, the light source experts invented the inflated incandescent bulb in the 1950s, and in the 1960s invented the addition of halogen to the inflated incandescent lamp, using the tungsten halogen cycle. A halogen lamp (or tungsten halogen lamp) that reduces the evaporation of tungsten filaments to extend the life of the lamp. At the time, such advanced light sources were quickly used in cars. The black tungsten layer evaporated onto the bulb becomes a tungsten halide due to a halogen compound such as iodine (bromo)methane, iodine (bromo)ethane or iodine (bromine) hydrogen charged in the halogen lamp. When the bulb is working, the high temperature causes the tungsten halide on the bulb to evaporate back into the space. In the vicinity of the high temperature tungsten wire of about 3000K, the tungsten halide is decomposed into halogen atoms and tungsten atoms, so that the density of tungsten vapor near the tungsten wire increases, and the evaporation of tungsten The reduction also eliminates the light absorption of the black tungsten layer on the glass bulb, which significantly increases the operating temperature of the lamp and increases the light efficiency from 9-10 lm/W of incandescent lamps to 20 lm/W or even 25 lm/W. In the 1970s, halogen lamps replaced large quantities of incandescent lamps for automotive lighting, and are still the dominant lamp in automotive headlamps. When the luminous efficiency of a tungsten halogen lamp used for automobile headlight illumination reaches 20 lm/W, the lamp life can be maintained between 200-300 hours. Some higher efficacy lamps may have a lifetime that can be reduced to 100 hours or even 50 hours, while light efficiency can rise to 25 lm/W to 30 lm/W.
After more than 30 years of glory, the luminous flux, luminous efficacy and longevity of tungsten halogen lamps have been difficult to meet the lighting requirements of today's high-speed vehicles, especially as the speed of the vehicles increases, giving drivers enough time to respond to various emergencies ahead. The effective front-illumination distance of the vehicle must be extended. At this time, the lighting technology technicians have designed a more advanced high-efficiency, high-brightness, long-life front-illumination light source for the automobile - the Xenon metal halide lamp for the vehicle.
II Xenon metal halide lamp for vehicles
The Xenon metal halide lamp for vehicles is an ultra-small metal halide lamp. When it is lighted, it uses its short-slit, ultra-bright arc as the illuminant. The luminous efficiency can be as high as 90lm/W and the life is up to 3000hr. The light source is filled with high-pressure helium gas of 6 atmospheres. When lighting, the helium gas is used as a starting gas to ensure that a high-pressure arc discharge is immediately formed in the lamp, and the bulb is heated at a faster speed to make the lamp bright enough to be illuminated on the order of seconds. Degree. The charging of the high-pressure helium gas greatly increases the ignition voltage of the lamp, and a high trigger pulse of 23 kV is required to ignite the lamp. Fig. 1 shows the high-voltage trigger in the lamp head of the D1S 35W automotive Xenon metal halide lamp. Of course, a high-performance ballast is needed to ensure the long life of the lamp. A typical 35W car Xenon metal halide lamp can emit 3,200 lm of light, three times that of a conventional 55W halogen lamp, and the latter has a luminous flux of 1,100 lm.
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The working principle and characteristics of the Xenon metal halide lamp for vehicles are completely different from the traditional incandescent lamps or halogen lamps for vehicles. The latter is a spiral wound with tungsten wire, which is heated to about 3000K when the current passes, generating blazing light. Most of its energy is converted into infrared radiation, so the light efficiency is not high.
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