How do xenon headlight bulbs differ from halogen ones? Who first used incandescent lamps in a car? What are “adaptive” headlights? We decided to trace the entire evolution of automotive lighting systems - from acetylene torches to the latest “smart” head systems, in which beams from LEDs will illuminate the road according to commands from the navigation system.
Until the light bulb
Before the light bulb there were candles. Or oil burners. But they shone so weakly that at night it was easier to leave the car at home than to travel “by touch.”
The first source of automobile light was acetylene gas - it was proposed to be used to illuminate the road in 1896 by the pilot and aircraft designer Louis Bleriot. Starting acetylene headlights is a ritual. First you need to open the tap of the acetylene generator so that water drips onto the calcium carbide, which is located at the bottom of the “barrel”. When carbide interacts with water, acetylene is formed, which flows through rubber tubes to the ceramic burner, which is located at the focus of the reflector. Now the driver must open the headlight glass, strike a match - and off you go. But after a maximum of four hours you will have to stop in order to reopen the headlight, clean it of soot and fill the generator with a new portion of carbide and water.
However, the carbide headlights shined brilliantly. For example, acetylene headlights created in 1908 by the Westphalian Metal Industry Company (as Hella was called at that time) illuminated up to 300 meters of the path! Such a high result was achieved through the use of lenses and parabolic reflectors. By the way, the parabolic reflector itself was invented back in 1779 by Ivan Petrovich Kulibin - the same Kulibin who created a three-wheeled “scooter” with a flywheel and a prototype of a gearbox.
The first automobile incandescent lamp was patented back in 1899 by the French company Bassee & Michel. But until 1910, carbon filament lamps were unreliable, very uneconomical and required heavy, oversized batteries, which also depended on recharging stations: automobile generators of suitable power did not yet exist. And then there was a revolution in “lighting” technologies - filaments began to be made from refractory tungsten (melting point 3410 ° C), which did not “burn out”. The first production car with electric lights (and also with an electric starter and ignition) was the 1912 Cadillac Model 30 Self Starter. After just one year, 37% of American cars had electric lighting, and after another four, 99% did! With the development of a suitable dynamo, the dependence on charging stations also disappeared.
By the way, if you think that Thomas Alva Edison invented the incandescent lamp, then this is not entirely true. Yes, it was Edison who got serious about light bulbs when the gas in his workshop was turned off for non-payment. And it was Edison in 1880 who presented a comprehensive rationale for using lamps with a carbon filament placed in the airless space of a glass ball. Edison also came up with a base. But the basic design of the incandescent lamp belongs to the Russian electrical engineer Alexander Nikolaevich Lodygin, a native of the Tambov province. He presented his development six years earlier. Moreover, historical documents mention a certain German watchmaker Heinrich Goebel, who managed to use electricity to heat a charred bamboo fiber inserted into a glass flask to glow, as much as 150 years ago, in 1854. But Gebel simply didn’t have enough money for a patent...
Dazzling Ideas
The problem of blinding oncoming drivers first arose with the advent of carbide headlights. They fought it in different ways: they moved the reflector, taking the light source out of its focus, moved the burner itself for the same purpose, and also placed various curtains, dampers and blinds in the path of the light. And when an incandescent lamp lit up in the headlights, additional resistances were even included in the electrical circuit during oncoming traffic, which reduced the filament’s intensity. But the best solution was proposed by Bosch, which in 1919 created a lamp with two incandescent filaments - for high and low beam. By that time, a diffuser had already been invented - a headlight glass covered with prismatic lenses, deflecting the light of the lamp down and to the sides. Since then, designers have been faced with two opposing tasks: to illuminate the road as much as possible and to prevent oncoming drivers from being blinded.
You can increase the brightness of incandescent lamps by raising the filament temperature. But at the same time, tungsten begins to evaporate intensively. If there is a vacuum inside the lamp, then tungsten atoms gradually settle on the bulb, covering it from the inside with a dark coating. A solution to the problem was found during the First World War: since 1915, lamps began to be filled with a mixture of argon and nitrogen. Gas molecules form a kind of “barrier” that prevents the evaporation of tungsten. And the next step was taken already at the end of the 50s: the flask began to be filled with halides, gaseous compounds of iodine or bromine. They “bind” the evaporating tungsten and return it to the spiral. The first halogen lamp for a car was introduced in 1962 by Hella - “regeneration” of the filament made it possible to raise the operating temperature from 2500 K to 3200 K, which increased the light output by one and a half times, from 15 lm/W to 25 lm/W. At the same time, the lamp life has doubled, heat transfer has decreased from 90% to 40%, and the dimensions have become smaller (the halogen cycle requires proximity of the filament and the glass “shell”).
And the main step in solving the problem of glare was made in the mid-50s - the French company Cibie in 1955 proposed the idea of asymmetrical distribution of low beams so that the “passenger” side of the road was illuminated further than the “driver’s” side. And two years later, “asymmetrical” light was legalized in Europe.
Deformation
For many years, headlights remained round, the simplest and cheapest form of parabolic reflector to make. But a gust of “aerodynamic” wind first “blown” the headlights into the wings of the car (the first integrated headlights appeared at Pierce-Arrow in 1913), and then turned the circle into a rectangle (the 1961 Citroen AMI 6 was already equipped with rectangular headlights). Such headlights were more difficult to produce and required more engine compartment space, but along with smaller vertical dimensions they had a larger reflector area and increased light output.
To make such a headlight shine brightly with smaller dimensions, it was necessary to give the parabolic reflector (in rectangular headlights a truncated paraboloid) even greater depth. And this was too labor-intensive. In general, the usual optical schemes were not suitable for further development. Then the English company Lucas proposed using a “homofocal” reflector - a combination of two truncated paraboloids with different focal lengths, but with a common focus. The Austin-Rover Maestro was one of the first to try on the new product in 1983. In the same year, Hella presented a conceptual development - “three-axis” headlights with an ellipsoidal reflector (DE, DreiachsEllipsoid). The fact is that an ellipsoidal reflector has two foci at once. The rays emitted by a halogen lamp from the first focus are collected in the second, from where they are directed into a collecting lens. This type of headlight is called floodlight. The efficiency of the “ellipsoidal” headlight in low beam mode was 9% higher than the “parabolic” one (conventional headlights sent only 27% of the light to its destination) with a diameter of only 60 millimeters. These headlights were intended for fog and low beam (a screen was placed in the second focus, creating an asymmetrical cut-off line). And the first production car with “three-axis” headlights was the BMW “Seven” at the end of 1986. After another two years, the ellipsoidal headlights became simply super! More precisely - Super DE, as Hella called them. This time the profile of the reflector was different from a purely ellipsoidal shape - it was “free” (Free Form), designed in such a way that the main part of the light passed over the screen responsible for the low beam. Headlight efficiency increased to 52%.
Further development of reflectors would be impossible without mathematical modeling - computers make it possible to create the most complex combined reflectors. Look, for example, into the “eyes” of cars such as Daewoo Matiz, Hyundai Getz or the “young” Gazelle. Their reflectors are divided into segments, each of which has its own focus and focal length. Each “slice” of the multifocal reflector is responsible for illuminating “its own” section of the road. The light of the lamp is used almost completely - with the exception of the end of the lamp, covered with a cap. And a diffuser, that is, glass with many “built-in” lenses, is no longer needed - the reflector itself does an excellent job of distributing light and creating a cut-off line. The efficiency of such headlights, called reflective, is close to that of floodlights.
Modern reflectors are “formed” from thermoplastic, aluminum, magnesium and thermoset (metalized plastic), and the headlights are covered not with glass, but with polycarbonate. The first plastic lens appeared in 1993 on the Opel Omega sedan - this made it possible to reduce the weight of the headlight by almost a kilogram! But polycarbonate “glass” resists abrasion much worse than real glass. Therefore, brush headlight cleaners, which Saab introduced back in 1971, are no longer made...
The century-long reign of the incandescent light bulb is coming to an end. The noble gases krypton and xenon help her “end her career” with dignity. The latter is considered one of the best fillers for incandescent lamps - with xenon, you can raise the temperature of the filament close to the melting point of tungsten and bring the light spectrum closer to that of the sun.
But ordinary incandescent lamps filled with xenon are one thing. But “xenon” with a bright blue glow, which is used on expensive cars, is fundamentally different. In xenon gas-discharge lamps, it is not the hot filament that glows, but the gas itself - or rather, the electric arc that occurs between the electrodes during a gas discharge when a high-voltage voltage is applied. For the first time such lamps (Bosch Litronic) were installed on the production BMW 750iL in 1991. Gas-discharge “xenon” is head and shoulders more efficient than the most advanced incandescent lamps - not 40% of the electricity is spent on useless heating, but only 7-8%. Accordingly, gas-discharge lamps consume less energy (35 W versus 55 W for halogen lamps) and shine twice as brightly (3200 lm versus 1500 lm). And since there is no filament, there is nothing to burn out - xenon gas-discharge lamps last much longer than conventional ones. 
But gas-discharge lamps are more complicated. The main task is to ignite the gas discharge. To do this, from 12 “constant” volts of the on-board network, you need to get a short pulse of 25 kilovolts - and alternating current, with a frequency of up to 400 Hz! A special ignition module is used for this. Once the lamp is lit (it takes some time to warm up), the electronics reduce the voltage to 85 volts, enough to maintain the discharge. 
The complexity of the design and inertia during ignition limited the initial use of gas-discharge lamps to low beam mode. The distant light is the old fashioned way - “halogen”. The designers were able to combine low and high beams in one headlight six years later, and there are two ways to get bi-xenon. If a spotlight is used (like the one invented by Hella), then the switching of light modes is carried out by a screen located in the second focus of the ellipsoidal reflector: in low beam mode it cuts off some of the rays. At a distance, the screen hides and does not interfere with the light flow. And in the reflective type of headlights, the “double action” of the gas-discharge lamp is ensured by the mutual movement of the reflector and the light source. As a result, the light distribution changes along with the focal length.
But according to the French company Valeo, by using separate gas-discharge lamps for low and high beams, you can achieve 40% better illumination than bi-xenon. True, not two, but four ignition modules are required - the expensive Volkswagen Phaeton W12 has such headlights. 
However, the future of HID lamps is not nearly as bright as the light they emit. Experts predict the greatest success for LEDs.
An LED is a semiconductor device that emits light when current passes. Until the early 90s, their automotive use was limited to display - the light output was too low. However, already in 1992, Hella equipped the three-ruble BMW Cabrio with a central brake light based on LEDs, and today they are increasingly used in rear lights as “dimensions” and brake lights. LEDs operate 0.2 seconds faster than traditional bulbs, consume less energy (for brake lights - 10 W versus 21 W) and have an almost unlimited service life 
But in order to replace bulbs with LEDs in headlights, a number of obstacles must be overcome. Firstly, even the best LEDs are still only comparable in efficiency to halogen lamps (light output is about 25 lumens per watt). At the same time, they are more expensive and require a special cooling system - after all, these are the same semiconductor devices as computer processors. But the developers assure that by 2008 the light output of diodes will reach 70 lm/W (the current xenon has 90 lm/W). So the first production LED headlights may appear in 2010. In the meantime, semiconductors are entrusted with secondary functions - for example, constant “daylight”, as Hella did by placing five LEDs in each headlight of the Audi A8 W12.
Adaptation period
People began making attempts to turn car headlights to follow the steering wheel immediately after the appearance of the headlights themselves. After all, it is convenient to illuminate the part of the road where you are going. However, the mechanical connection between the headlights and the steering wheel did not allow the angle of rotation of the beams to be correlated with the speed of movement, and the rules of the beginning of the century simply prohibited “adaptive” light. An attempt to revive the original idea was carried out by Cibie. In 1967, the French introduced the first mechanism for dynamically adjusting the headlight angle, and a year later they began installing turning high beam headlights on the Citroen DS.
Now the idea of turning lighting is being revived - at a new, “electronic” level. The simplest solution is an additional “side” light, which lights up when the steering wheel is turned or the turn signal is turned on at speeds up to 70 km/h. For example, the Audi A8 (first use) and Porsche Cayenne have similar headlights. The next step is truly cornering headlights. In them, the bi-xenon spotlight, taking into account the speed of movement, the angle of rotation of the steering wheel and the angular velocity of the car around the vertical axis (“turn sensor”), rotates after the steering wheel within 22° - 15° outward and 7° inward. BMW, Mercedes, Lexus, and even Opel Astra are equipped with such headlights. The third option for “adaptive” light is combined. At high speeds, only the rotating spotlight is active, and during slow turns or when maneuvering, the static lighting is “connected” (it has a larger coverage angle - up to 90°). The Opel Signum is equipped with such headlights.
But perhaps the most interesting development is VARILIS: a system that Hella is developing together with several car manufacturers. The abbreviation stands for Variable Intelligent lighting system. One of the variations is the VarioX system, which allows the headlight to operate in five light modes. To do this, in the “xenon” spotlight, instead of a screen that turns on the low beam, there is a cylinder of complex shape. Light modes change when the cylinder rotates. So, for example, in the city the headlights shine close but widely, while on the highway the low beam slightly changes the shape of the beam - for greater range. VarioX is expected to be ready for mass production in 2006. And a little later, European regulations will allow headlights to be linked to the GPS system. BMW was one of the first to introduce such a development in 2001. Think of the X-Coupe concept car with its asymmetrical design. His headlights turned at the command of the GPS navigator, taking into account the speed of movement, steering angle and lateral acceleration. And the navigation system will also allow you to “predict” turns and give a command to automatically change the light distribution, say, when crossing the English border - after all, the VarioX system allows this too!
And the next step is to combine headlights and night vision systems. But this is a topic for another conversation... 
America - Europe
The approach to lighting systems in the Old World and overseas is radically different. Let's start with the fact that American laws until 1975 prohibited the use of non-round headlights and halogen lamps! Moreover, in the States, the lamp and headlight were combined into one - headlight lamps have been used overseas since 1939. Such devices had one advantage - the tightness of the headlight lamp made it possible to cover the surface of the reflector with silver, the reflectivity of which reaches 90% (versus 60% for chrome-plated reflectors common at that time). But, of course, the entire headlamp had to be replaced.
And the main difference is that in Europe, since 1957, asymmetric light distribution has been adopted with better illumination of the “passenger” side of the road and with a clear cut-off line. But in America, the use of headlights with a border of light and shadow was allowed only in 1997. Allowed, but not required! The light of “American” headlights is distributed almost symmetrically, completely blinding oncoming drivers. In addition, Americans adjust headlights only vertically. And in the USA and Canada there is no uniform procedure for certification of lighting devices. Each manufacturer only guarantees that its headlights comply with the Federal Motor Vehicle Safety Standard (FMVSS), and this has to be confirmed, for example, in the event of an accident due to the fault of the lighting devices.
Vehicles officially imported from the United States are expected to be tested to ensure compliance with European regulations. “American” headlights are marked with the abbreviation DOT (Department Of Transport, Ministry of Transport), and “European” ones are marked with the letter “E” in a circle with the number code of the country where the headlight is approved for use (E1 - Germany, E2 - France, etc.). d.).
It should be taken into account that when passing technical inspection in Russia, “American” headlights and head optics of “right-hand drive” cars can create problems, since the regulatory document, GOST R 51709–2001, regulates the “left-asymmetrical” distribution of light and a clear cut-off line.
H1 - D2: knight move
Automotive lamps usually differ in the design of the base and light output. For example, in two-headlight systems, H4 lamps are most often used - with two filaments, for high beam and low beam. Their luminous flux is 1650/1000 lm. The “foglights” use H8 lamps - single-filament, with a light flux of 800 lm. Other single-filament lamps H9 and HB3 can only provide high beam (luminous flux 2100 and 1860 lm, respectively). And the “universal” single-filament lamps H7 and H11 can be used for both low and high beam - depending on the reflector in which they are installed. And as always, the quality of the lamp depends on the specific manufacturer, equipment, concentration and types of gases (for example, H7 and H9 lamps are sometimes filled not with halogens, but with xenon).
Gas-discharge “xenon” has different designations. The first xenon lamps were devices with the indexes D1R and D1S - they were combined with an ignition module. And behind the indices D2R and D2S are second-generation gas-discharge lamps (R - for a “reflective” optical design, S - for a spotlight).
There are many misconceptions when it comes to headlights. Considering that headlights are one of the most important features of cars, many people think that there is no misinformation about front headlights. After all, it seemed that car front optics had a simple and understandable design. However, there are many types of headlight designs in the auto industry, causing confusion. In this article, I want to clear up any misconceptions and explain the design of various headlights nowadays.
And so I divided the article into three parts:
- Housing and design of headlights
- Lamps
- Other relevant information/Miscellaneous
The headlight housing is the part of the optics within which the lighting lamp is installed. As you know, in the modern car market there are many different lighting lamps, ranging from conventional halogen to laser technology. The design of the headlight housing also depends on what kind of lighting lamp is installed in the front optics.
Headlights with reflectors installed in the front optics housing are the most common in the automotive industry today. Although at the moment there is a tendency to replace headlights with reflectors with lensed optics. I'm not going to bore you with the science of how a car headlight works. In short, a lighting lamp is usually installed inside the headlight next to the reflector. The light that the headlight emits is reflected from the chrome paint that is applied to the reflector. As a result, the light of the lamp, reflected from the chrome surface, comes out onto the road.
Typically, a halogen car lamp also has a small area of chrome or other protective material (usually located on the front end of the lamp) that prevents direct light from shining into the eyes of oncoming drivers. As a result, the lamp does not emit light directly onto the road, but hits a reflector, which scatters the light rays and sends them onto the road.
Recently it seemed that this type of lamp would soon disappear from the auto industry. Especially after they appeared. But the bottom line is that today, halogen car bulbs are still the most common in the automotive world.
Headlights with lenses inside are currently gradually losing popularity to optics with reflectors. Let us remind you that lensed headlights first appeared on expensive luxury cars. But then, as technology became cheaper, front lens optics began to appear on ordinary, inexpensive vehicles.
What are lensed front optics? As a rule, this type of headlights uses lenses instead of reflectors (a special optical bulb that does not reflect the emitted light from the lamps onto the road, but in fact, uses projection to transmit illumination to the road).
Currently, there are a huge number of different types of lenses and designs of lensed headlights.
But the meaning of lensed optics is the same. What is a lens in a headlight and how does it work?
The fact is that licked headlights form a beam of light to illuminate the road in a completely different way, unlike optics with reflectors.
For example, there is also a chrome-plated reflector inside the lens that reflects light from the lamp. But unlike a conventional reflector, the structure of a lensed reflector is created in such a way as not to direct light onto the road, but to collect it in a special place inside the headlight - on a special metal plate. This plate, in essence, collects light into a single beam and redirects it into the lens, which in turn projects a directed beam of light onto the road.
Typically, a lens headlight provides superior light output with a sharp cutoff line and focused beam.
As we have already said, the most important thing in any headlight is the light source. The most common light sources in car headlights are halogen incandescent lamps.
In some cases, you will have to purchase new optics. But since LEDs have a very long service life, even today the use of LED road lighting is economically justified.
At the moment, a number of automobile companies have already begun to introduce a new generation of optics on some expensive models, which are equipped with innovative lasers as light sources.
True, laser optics still remain a rarity in the automotive industry due to the high cost of manufacturing such optics.
So how do laser optics work? In fact, laser headlights also use LEDs, which, when exposed to the laser, produce a more uniform and brighter glow. Thus, the luminous flux of conventional LEDs is 100 lumens, while in laser optics LEDs produce 170 lumens.
The main advantage of laser headlights is their energy consumption. So, compared to LED automotive optics, laser headlights with LEDs consume half as much energy.
Another advantage of laser headlights is the size of the diodes used. For example, a laser LED, which is one hundred times smaller than a conventional LED, produces the same level of luminescence. As a result, this allows automakers to reduce the size of headlights without losing the quality of road lighting.
Unfortunately, laser light sources in the automotive industry are very, very expensive these days. So laser optics will not be widely used in the near future. But in the future, most likely, laser headlights will gradually replace all traditional car lighting sources.
Now that we've covered all the different types of automotive front optics technologies, it's time to talk about some of the issues that arise. So, for example, let's find out whether it is possible to use xenon lamps in halogen headlights and vice versa?
As a rule, to use xenon lamps, the front optics must be equipped with a lens that projects light onto the road. Also, xenon optics are required; as a rule, they are equipped with a headlight range control.
Mostly these days, automatic headlight leveling is used, which changes the angle of the lens in order to protect oncoming drivers from the bright daylight of xenon headlights. The angle changes depending on the number of passengers inside. In addition, all xenon headlights must be equipped with an optics washer, since a xenon light source is not effective with dirty headlights.
As for halogen lamps, unlike xenon lamps, they can be installed in lensed optics. What about LEDs? Since LED lamps, as a rule, have a directional light source, it is not safe to install them in a headlight with conventional reflectors, since in this case the efficiency of road illumination will be low. Therefore, most automakers equip LED optics with lenses that project light from the LEDs onto the road. More about this below:
In principle, it is possible, but nothing good will come of it. Firstly, according to Russian legislation, the use of xenon lamps in headlights with reflectors is strictly prohibited, since this creates a danger for oncoming drivers on the road, who may be blinded by the bright source of light from xenon lamps scattered by the headlight reflectors.
As a result, by installing xenon lamps in headlights with reflectors, you will only get an externally beautiful glow. But road illumination will be much worse than when using halogen lamps, since xenon lighting sources require lensed optics. In addition, xenon lamps installed in the reflector provide disgusting illumination of the road in rainy weather.
In particular, we would like to note that xenon lamps will quickly burn out the chrome coating of your reflectors. As a result, even if you subsequently install halogen lamps again, your headlights will not shine as efficiently as before.
As we have already said, the installation of xenon light sources in car headlights equipped with reflectors for halogen lamps is prohibited.
Thus, in accordance with Part 3 of Article 12.5 of the Code of Administrative Offenses of the Russian Federation, driving a vehicle on the front of which is installed lighting devices with red lights or red reflective devices, as well as lighting devices, the color of the lights and the operating mode of which do not comply with the requirements of the Basic Regulations for the admission of vehicles to operation and duties of officials to ensure road safety entails deprivation of driver's license for a period of 6 months to 1 year with confiscation of xenon equipment and lamps.
That is, in other words, if you illegally install xenon lamps on your car in headlights that are not intended for this type of light source, then you will not be fined, but will immediately be deprived of your driver’s license, and after the expiration of the deprivation period you will have to retake the theoretical exam.
Theoretically it is possible. But you will have to buy and install either the Chinese version, which is unlikely to please you with the quality of road illumination and durability, or you will have to disassemble the headlight and install another block lens. In the latter option, the quality of lighting will indeed be better and perhaps even more efficient than xenon light sources. But again, if you buy high-quality LED lamps and a block lens for them, which costs a lot of money.
As for the legislation, at the moment there is no direct ban on the use of LED low and high beam lamps in conventional headlights. There are also no uniform standards or GOSTs yet that would prescribe rules for the installation and use of LED low- and high-lighting sources on vehicles.
At the moment, rules and standards are just being developed. So in the near future, most likely, everything will happen exactly the same as with xenon lamps. Remember what was happening on Russian roads 10 years ago, when every second car was equipped with non-factory xenon. It's the same picture today.
Every day there are more and more cars on the road with non-factory LED low and high beam lamps, when most owners of cars equipped with headlights with conventional reflectors no longer use xenon lighting sources for fear of losing their license (although many have already realized that “collective farm” xenon really reduces road safety).
So using LED lamps in reflectors or lenses for xenon is just as dangerous as using “collective farm” xenon, since an LED lamp will not effectively illuminate the road in a reflector or lens designed for a xenon lamp.
Remember that LEDs also require a special spotlight (a lens unit with special equipment that collects light from the LED lamp into a beam and directs it into the glass lens).
The term Bi-Xenon means that the car is equipped with a single xenon lamp that performs the work of both a low beam source and a high beam source. Those cars that are not equipped with Bi-Xenon headlights are usually equipped with either halogen lamps or combined light sources (low beam: xenon lamps, high beam: conventional incandescent halogen lamp).
There are two types of Bi-xenon headlights common in the automotive industry.
The first type uses a special shutter in the lens located outside the xenon lamp bulb. As a result, when the high beam is turned on, the curtain directs the light source to the reflector, which then sends light to the lens in the high beam spectrum.
With the second type of Bi-xenon headlights, a special Bi-xenon lamp is used, which, for example, when the high beam is turned on, independently moves the lamp bulb relative to the reflector built into the lens. As a result, light is projected onto the road in the low-beam spectrum.
There is currently great controversy about this. As they say, how many people, so many opinions. However, today it is already known that halogen lamps cannot withstand any competition compared to xenon and LED artificial light sources.
Vehicle lighting devices perform their important role - from illuminating the road to warning other road users about our intentions (turning, stopping, etc.). Lighting devices can be divided into two groups - headlights and rear lights. We've already talked about headlights in detail, but now it's time to talk about the rear lights.
So, what's special about taillights, what should they be like, and what interesting technologies do modern engineers use to create them?
In fact, the main functional responsibility of the rear lights is to inform everyone driving behind us about what we plan to do while driving - stop, turn, back up, and so on.
For this, there is a set of special light sources, which, as a rule, are combined into one housing.
In the literature, such a unit is called differently - rear combination lights, rear light module or rear light unit. Typically this unit includes the following lighting devices:
The rear fog lamp and license plate lights are installed separately from the unit.
Of course, the set we have listed, located in one case, is not at all an unshakable rule, because manufacturers really like to experiment with the design and shape of flashlights.
Because of this, the above-mentioned vehicle lighting devices may not be in a single unit, but they should be located in the rear of the car in any case, since this is regulated at the legislative level in many countries of the world.
Let's go through each of the lighting devices we have listed to figure out how much they are really needed.
In common parlance - dimensions. They serve, as you might guess, to designate a vehicle on the road so that other drivers can see our car in advance, standing, for example, at the side of the road.
In the rear of the car, they are located on both sides of the body, should have a red glow and, as a rule, are structurally combined with brake lights.
In turn, brake lights also have a red glow, but much more intense. They turn on automatically when you press the brake pedal.
By the way, in many countries a mandatory condition is the presence of an additional brake light, which must be installed in the middle of the body and above the line of the main lights.
Our next hero is the reverse signal. This is a white light, indicating that the car has engaged reverse gear and is starting to move backwards.
The functions of turn signals, we think, are already clear to everyone. The only thing I would like to note is that they should be yellow, located on both sides of the body and signal the maneuver by flashing at a frequency of 60 to 120 times per minute.
Now, on almost all cars, double turn signals (yellow) are installed on the side of the front fender
Reflectors are an important element in the dark. Especially if the vehicle is parked and all lights are, of course, turned off. When light hits them, reflectors are effective over a long distance and let other drivers know in advance that there is a car ahead and they need to be careful.
Optional rear fog lights are also a desirable feature. It has an intense red glow, necessary to identify itself in foggy or poor visibility conditions. In order to prevent confusion with the brake light, manufacturers mount the fog lamp separately from the headlight unit, although this is not a uniform rule.
Vehicle lighting devices must include illumination of rear license plates. It should be white and properly cover the area of the entire license plate. This element of lighting equipment turns on automatically along with the side lights.
Our story about taillights would be incomplete without a description of the technologies that automakers resort to to make them.
For a long time, the only possible light source in these car lighting devices was ordinary incandescent light bulbs. This imposed significant restrictions on the design of flashlights, and in general many problems are associated with them - low reliability, inertia (lamp turn-on time is about 200 ms), and so on.
With the rapid development of semiconductor technologies, automakers have greater opportunities for the manufacture of lighting equipment. We are, of course, talking about LEDs.
Firstly, they have a much longer service life, secondly, they have low power consumption, and thirdly, their turn-on time is only 1 ms.
These factors, as well as the opportunities that have opened up for designers - after all, you can create any design, shape or pattern from LEDs - have now almost completely replaced incandescent lamps from the design of rear lights.
In addition, car headlight developers are increasingly using fiber optics to create original effects - stripes, rings, and various geometric shapes. Light guides made of polycarbonate (PC) or polymethyl methacrylate (PMMA) create a uniform glow along the entire length of the fiber, while the light source can be located on one side, somewhere deep in the node.
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Headlights of modern cars can be divided into several main types - high and low beam headlights, fog lights and specialized additional headlights.
Additional headlights can be called spotlights, which ensure safe high-speed movement on the highway at night, rear and side lighting for comfortable maneuvering in parking lots or off-road in the dark. The characteristics of the light of a particular type of headlight are determined by the location of the lamp relative to its reflector and the pattern on its glass, as well as the placement of the headlight on the vehicle.
In rain, fog or thick snow, a conventional low-beam headlight reduces the effectiveness of illuminating the road. The first reaction to deteriorating visibility is to turn on the high beams, but at the same moment the driver realizes that the situation has only worsened, this is due to the blinding effect. The explanation is simple: the high beam has no restrictions and is not cut off at the top of the light beam. The high beam beam, reflecting from droplets of fog or snowflakes, blinds the driver with the reflected light.
Under constant external illumination, the amount of light entering the eye per unit time is proportional to the area of the pupil. The eye reacts to external illumination by reflexively dilating or constricting the pupil, and the pupil of the unlit eye also reacts; this is called a friendly reaction to light.
Responsiveness to light is a useful regulatory mechanism because bright light conditions reduce the amount of light reaching the retina. Thus, the light from the headlights illuminating the road becomes poorly visible or completely invisible, this is the effect of blinding.
The fog lamp is specially designed for bad weather conditions and is initially designed for narrowly targeted use.
Fog lights have a wide light distribution pattern horizontally and a very narrow beam vertically. The main task of fog lights is to shine as if under fog, rain or snow, thereby not blinding the driver with reflected light, as happens when the high beams are turned on.
Requirements for fog lights: the upper cut-off line must be as sharp as possible, the dispersion angle in the vertical plane is the smallest, about 5 degrees, and in the horizontal plane the largest, about 60 degrees, and the maximum light intensity must be close to the upper cut-off line.
We strongly recommend that you do not install xenon lamps in fog lights. The focusing of the headlight is disrupted because A xenon lamp does not have a fixed light source, but a rotating high-voltage arc that forms a luminous ball. The headlight, designed for a specific type of lamp, cannot cope with the new light source and multiple mutual reflections and refractions occur in the reflector, which causes blurring of the cut-off boundaries and ultimately blinding oncoming and passing drivers. In addition, the fog lamp loses its ability to provide visibility and illumination of the road in bad weather conditions.
There are also rear fog lights. That's why they are called that because they are designed for conditions of insufficient visibility for drivers driving behind you. It is prohibited to connect them together with brake lights, or to turn them on on a clear night. For example, in a traffic jam, fog lights with fairly powerful 21W lamps will, if not dazzle, then irritate drivers driving behind. And stop signals are much less visible against their background. In other words, rear fog lights turned on inappropriately will not help, but will do harm!
 Diagram light distribution |
 This is how the driver sees fog in headlights low beam |
 The same fog, but without low beam with PTF on |
 PT F Module D100 |
A low beam headlight is a light device designed to illuminate the road ahead of a vehicle. The lighting parameters of low beam headlights are selected to ensure visibility of the road ahead at 50-60 meters and safe driving on a relatively narrow road without dazzling oncoming drivers.
Modern lighting systems can be divided by type of light distribution - European and American.
European and American car headlight lighting systems are different both in the structure of the light beam created and in the principles of its formation. This is due to both the peculiarities of traffic organization and the quality of the road surface. Both systems have both two and four headlight designs.
American cars are equipped with headlights, or more often headlight lamps, in which the low beam filament is shifted above the horizontal plane. Thanks to this arrangement, the luminous flux of the low beam is shifted towards the right side of the road and inclined downwards. The entire reflective surface of the headlight reflector is involved in the formation of beams of both low and high beam.
The European lighting system is designed differently; the low beam filament is shifted upward relative to the focus of the reflector, while the filament is shielded from the lower hemisphere by a special metal screen.
Only the upper hemisphere of the headlight reflector is involved in the formation of low beam. On the left side, the screen is cut at an angle of 15 degrees, this allows you to get a clear asymmetrical beam of low beam. The border of the illuminated zone is clear, the right side of the road is brightly lit, and the left part of the beam does not blind oncoming drivers. The low beam illumination range does not exceed 50-60 meters. Modern low-beam headlights, as well as high-beam ones, are made with transparent glass, and the formation of an asymmetrical beam occurs on the surface of the reflector, which has a pronounced relief. This design allows you to increase the brightness of the luminous flux, since the beam is not scattered on the surface of the corrugated glass of the headlight and, as a rule, has the same brightness over the entire illuminated plane. This technology is called free form and is used on all modern cars, both in head and additional optics.
A high beam headlight is a light device designed to illuminate the road ahead of a vehicle in the absence of oncoming traffic. High beam provides illumination of the road and roadside at a distance of 100-150 meters, creating a bright, flat beam of light of relatively high intensity (min. requirements).
High beam headlights can be divided into two categories. These are standard high-beam headlights included in the vehicle and additional mounted headlights, of various shapes and sizes with various characteristics of the light beam and lamp power.
As a rule, standard headlights of modern cars, for the sake of design, have modest reflector sizes and have the minimum required characteristics. For infrequent night trips, the light from the standard headlights is quite enough. But, if traveling long distances at night is a necessity for you, then by installing additional high-beam headlights, you will significantly protect your driving at night.
The range of high beam headlights is so diverse that it allows you to choose mounted headlights for both a compact passenger car and a prepared SUV. Having decided on the size and design of the headlights, it is necessary to select the main lighting characteristics, namely the shape of the beam and the aperture of the headlight.
High-speed traffic on a highway at night requires headlights to have maximum beam range in order to respond in a timely manner to an obstacle. For such conditions, headlights with a narrow beam are best suited, where the entire aperture of the headlamp is aimed at achieving maximum range. This type of headlight is called a spotlight. The spotlight creates a narrow, weakly scattering concentrated beam and is used to illuminate objects at a considerable distance up to 1 kilometer.
If you often travel on secondary roads, the width of the beam that illuminates the side of the road and the surrounding area is much more important, because The side of the road at night is fraught with many surprises. For such conditions, we recommend high beam headlights and wide beam high beam headlights. These headlights are not as “long-range” as spotlights, but their range is quite sufficient for a timely reaction to an obstacle.
We remind you that in order to avoid dazzling, the high beam must be switched to low beam at least 150 meters before the oncoming car, and also at a greater distance if the oncoming driver periodically switches his headlights. Glare can also occur from the rearview mirror. Unexpected blinding of drivers of oncoming cars driving behind a break in the longitudinal profile of the road or around a bend is very dangerous. In these cases, you need to switch the high beam to low beam in advance.
The first to realize the benefits of always-on headlights were the Scandinavian countries. Until recently, they were partially supported: in some places it was obligatory to turn on headlights only outside the city or only in winter. But it seems that these are only half measures...
European statistics and numerous studies have convincingly confirmed that “daylight” lights on cars need to be legalized. And so all the countries of the European Union decided to join their northern neighbors - since 2003, switched on headlights have become as mandatory a driving condition as wearing a seat belt!
In twenty districts of Lower Saxony, a campaign called “Turn on the lights during the day” was held. Information boards have been installed on dangerous sections of roads urging drivers to turn on their headlights during daylight hours. And although the calls were advisory in nature, German pedantry elevated them to the rank of law. The results were impressive: the number of victims on the designated routes was reduced by a quarter!
Daytime running lights, or daytime running lights, are lights on the front of a vehicle that emit bright white light to increase the visibility of the vehicle in daylight conditions.
Advantages of daytime running lights:
. Low power consumption, which practically does not increase fuel consumption.
. Does not increase wear on conventional headlights.
. Optimal contrast on a bright sunny day.
Since February 2011, cars and light trucks sold in all EU countries must be equipped with so-called daytime running lights.
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To carry out construction, installation, loading and similar work at night, specialized light is required. Since standard low- and high-beam headlights, and even more so spotlights, cannot create the necessary light spot, special work lights designed for illuminating large areas are used for these purposes.
Due to their specific specificity, Hella work lights have many models that differ in the level of protection, number of lamps and light distribution.
An important point is that all modern Hella work lights are built using modern FF technology (FF is an abbreviation for Free-Form - free form or free surface). The calculation of the reflector surface was performed on a computer; the result is an optimal fit of the reflector surface to the lamp with increased luminous efficiency.
Certain parts of the reflector, calculated point by point, are responsible for illuminating a certain part of the road. The light flux generated by the FF reflector is distributed more evenly than from a classic parabolic reflector and creates an evenly illuminated section of the road with soft transitions and without sharp contrasts. For example, in most headlights the intensity of the light beam has a smooth transition from maximum brightness at the top of the optical element with a smooth decrease towards the bottom. This effect is created by a FF reflector for uniform illumination. The beam, falling on the plane of the road surface, creates a uniform fill with the same brightness of the spot along its entire length.
Hella work lights have several types of light distribution:
Long Range- Most headlights with this index have transparent glass, without a pattern; headlights of this type form a light spot at some distance from the light source, and the gap between the headlight and the light spot remains minimally illuminated with a clear cut-off line. Such light distribution eliminates unwanted illumination of structural elements of the vehicle (hood, bucket or blade). As a rule, halogen work lights have these properties; headlights with a gas-discharge lamp (xenon) and the Long Range light distribution index form a light corridor of small width, but an impressive range of up to 140 meters.
Close Range- The wide, flood beam of this headlight illuminates not only a large area, but also vertical obstacles. The light spot is formed in the immediate vicinity of the light source. There is a feeling that the light is “peeping” around the corner. To increase the brightness of the spot, we recommend sticking out headlights with two 55W 12V or 70W 24V lamps or headlights with a gas discharge lamp (xenon).
Ground illumination- Specialized headlight to illuminate the ground with a very wide and bright beam, superior to Close Range headlights. In the upper part of the light beam, the headlight has a clear cut-off line, which does not lead to blinding of an outside observer.
Ground illumination is ideal for cases when you need to highlight the ground over a large area. The headlight is supplied with both H9 65W halogen lamps and gas discharge lamps (xenon).
Reversing Light- There is another type of light distribution, Reversing Light, which is indirectly related to work light headlights; the only thing they have in common is the level of protection of the headlights and the same housings. Reversing Light - This is a specialized light for reversing, the headlight forms a wide flat beam “fan” and requires a minimum mounting height. In this case, the light from the headlight is spread out on the plane, creating a maximum area of illumination and without blinding drivers moving behind you.
It makes no sense to use work lights as work lights:
- Low beam headlights.
- High beam headlights.
- Fog light.
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Anti-fog light |
Work light |
New technologies are constantly being introduced into car design. Modern innovations do not bypass car headlights, which very often use non-standard light sources. New technologies are being introduced into the automotive industry so quickly that not all car enthusiasts have time to study them. To fill this gap in memory, we decided to understand in as much detail as possible the advantages and disadvantages of the most common types of car headlights today.
This type of lamp, which car enthusiasts quite often install in the headlights of their cars, is actually the most affordable option if we take into account their cost. Wherein The operating life of halogen incandescent lamps is 1 thousand hours(provided there is no constant energy drop). However, there are a number of reasons why car enthusiasts refuse to use them, and these reasons lie in the peculiarities of the functioning of halogen lamps.
Interesting!To achieve the required color temperature of a xenon lamp, after pumping in xenon, it is cooled to 190°C, and then subjected to an annealing procedure.
A halogen incandescent lamp has the following design:
- the outer body of the lamp is made of fairly durable glass, which can also withstand very high temperatures;
The inside of the lamp is filled with a mixture of gases (argon and nitrogen);
The main element of a halogen lamp is a tungsten filament, which is directly connected to the car’s electrical network, from which voltage is supplied to it at the right time.
When voltage is applied, the tungsten filament can heat up to a temperature of 2500°C. Thanks to this, the gas begins to glow, and the lamp emits a fairly intense light, which is quite enough to illuminate the roadway.
Thus, when the lamp is turned on, a large amount of heat is additionally generated, which, in fact, is no longer used. Under the influence of this heat, tungsten gradually evaporates, as a result of which the filament bursts, and the lamp has to be changed.
But this is not all the features of halogen headlights. You need to be especially careful when replacing them. Never touch the glass of a new lamp with bare fingers. If even a few drops of sweat remain on the glass, it will already be considered damaged and may simply break during use.
Advantages of halogen incandescent lamps
Although this type of headlight lamps is quite difficult to operate, they still have a number of significant advantages that should not be overlooked. Automakers install them on their creations for the following reasons:
1. Due to the high temperature of the tungsten filament, a very bright beam of light is formed;
2. Manufacturers have made sure that such lamps are produced in a wide variety of types and sizes, so that for each model and brand of car you can easily select the right halogen incandescent lamp;
3. Halogen lamps can be painted in any color, which allows them to be installed in any type of headlights, even in emergency lights, and can also be used for various design solutions;
4. And, of course, we cannot help but remember once again the long service life of such lamps, since they have to be changed quite rarely.
What makes car enthusiasts abandon halogen lamps?
Halogen incandescent lamps can hardly be called economical, since to obtain truly bright light you have to consume a large amount of electricity. At the same time, experts call such consumption empty, since the heat received from the incandescent lamp cannot be converted into useful action.
But the most important disadvantage is the need for additional care. The point is that a long period of operation of these lamps can only be ensured under ideal operating conditions. If even a drop of moisture or a few specks of dust gets on the lamp, it may simply crack within a few days.
We are talking about xenon lamps, which were first used on BMW cars back in 1991. Since these cars are representatives of the premium segment, such an innovation immediately received a lot of attention from potential buyers and other automobile concerns. Indeed, gas-discharge lamps as car headlights are a very good option with a number of undeniable advantages: not just spectacular, but truly effective lighting.
The choice of car designers fell on xenon lamps also for the reason that they consume several times less electrical energy from a car battery - only 7% instead of 40%.
Thanks to this, the car design can be equipped with devices of higher power. In addition, such lamps last many times longer than halogen lamps - in optimal operating mode they can shine for about 3000 hours instead of 1 thousand. This is due to the type of design of gas-discharge lamps, in which the usual incandescent filament is absent. The light from them is formed due to the glow formed due to the rainbow between the electrons.
Advantages of xenon
At night, gas-discharge lamps give the driver the opportunity to see not only the section of the road that is located directly in front of the bumper of his car. Their power allows you to see a very wide and distant space, which in general has a rather positive effect on the traffic safety of the driver who is driving a car equipped with xenon headlights.
Speaking about which is better - xenon or halogen, it should be noted that gas-discharge lamps have a significant advantage, because they practically do not heat up during operation. Thanks to this feature, firstly, they do not create a large amount of energy, which then cannot be used anyway, and secondly, they do not expose other elements of the headlamp to heat, providing them with a fairly long service life.
Disadvantages of using gas discharge lamps as car lighting
To install headlights with xenon lamps on a car, you will also need to install special ignition units for such lamps. They are quite expensive, so the initial investment will cost the car owner a pretty penny. In addition, gas-discharge lamps can only be installed in pairs, which will ensure the formation of a uniform color. The fact is that during operation, the color of the beam emitted by xenon headlights constantly changes (it is almost impossible to see this difference with the naked eye; it becomes noticeable only when a new lamp is installed in parallel in the second headlight of the car).
In addition, xenon headlights, even if they were installed by professionals, can bring very severe discomfort to drivers of oncoming cars. The fact is that if the surface of the headlight becomes dirty during operation, bright rays of light begin to refract and be thrown in different directions. But there are often cases when, even with completely clean glass, owners of cars with xenon pose quite a danger to oncoming traffic.
For this reason, it is better to trust the installation of gas-discharge lamps to specialists who can align the beam of light from it, thereby making your car as safe as possible. First of all, if the luminous flux of such a lamp exceeds 2500 lumens, auto correctors and special headlight washers must be installed on the car along with the lamps. This will again increase the final cost of installing such headlights, which is their significant drawback.
If you want to install xenon on your car, then the most affordable and safe option would be to use lamps from Philips, which in their original design are combined with an igniter, which makes them more affordable. In addition, this manufacturer produces lamps with the lowest possible light intensity - only 2500 lumens (in the traditional version, this figure can rise to 4000 lumens). Thus, the light from the headlights, although not too bright, is much better than from halogen lamps. By the way, The light intensity from halogen headlights is only 1000-1500 lumens.
But all this still does not allow us to avoid all the disadvantages of xenon, especially if we take into account the fact that there are LED car headlights on the market, which are preferred by almost all modern car enthusiasts. We explain why exactly below.
This type of headlights can be called the most desirable for installation on a car, but only if really high-quality devices are used, and not a cheap Chinese knockoff. They serve for a very long time and uninterruptedly, for this reason, recently all new cars in the premium segment are equipped with LED headlights.
It is very important to separate the two concepts of LED headlights and lamps. In the first case, in addition to the lighting device, a computerized control unit and a fan are also installed, which allows cooling the device during intensive operation. Such headlights are very expensive, and to install them on your car, you will have to spend at least 400 USD.
Interesting to know!The light output from LED headlights depends solely on how many LED bulbs are installed in the headlight. For this reason, LED headlights do not always provide a better performance than halogen headlights.
Why pay more then, you ask? The fact is that the presence of an individual control unit allows you to automatically control the switching on and off of the high beams. This may be due to the fact that the headlight itself is constructed from several diodes at once, each of which is assigned the function of illuminating a specific section of the road. Thus, when a car meets on the road, the control unit itself will turn off several diodes so as not to illuminate it, but during a maneuver around a turn it will turn on additional LEDs so that the driver can see a wider section of the road.
Pros of LED headlights and lamps
LED headlights have a fairly high power – 30 W, and a lighting range of about 3600 lumens. Thus, in terms of lighting intensity, they are actually equal to the xenon ones described above.
But the biggest advantage of LED headlights is their service life, which can easily reach 30 thousand hours(using quality equipment and professional installation). In addition, unlike xenon, there is no prohibition on them, and their installation does not require special corrective devices.
A very important fact is also that LED headlights emit light that is almost identical to natural light, so they are virtually harmless to human eyes.
All the advantages of this type of lamps allow you to install them both for side lights and for daytime running lights. Very often, LED bulbs are also installed in the cabin to signal the switching on of a particular device. Even more often they are used for car tuning.
Obvious disadvantages of LED headlights
There are quite a lot of disadvantages to such headlights, so we list them in the form of a list:
1.
Although LED headlights are slightly cheaper than xenon ones, you will have to pay a lot of money for the entire device. True, due to their growing popularity, the price for them is falling more and more, although in parallel with the original and truly high-quality lamps, dangerous fakes are increasingly appearing.
2. If an LED headlight burns out during operation, simply replacing the lamp will not work. The complete set will need to be replaced.
3. LED headlights have a rather complex design, which gets quite hot during operation. But if in the case of halogen lamps such an increase in temperature does not have any side effects, then for LED headlights a cooling device is required.
4. Using LED lamps without a special control unit makes the light from them ineffective. For this reason, only fully equipped LED headlights should be installed on a car. Otherwise, the effect from them will be even worse than from halogen ones.
In 2014, BMW launched its new car equipped with laser lighting devices. Audi designers also introduced a similar innovation into their sports cars. Why did sports cars begin to be so actively equipped with a new type of automotive lighting - laser headlights?
First of all, for the reason that this type of lighting allows you to get an extraordinary range of light, which can spread even 600 meters, which is not possible for any of the above types of lighting. Moreover, the laser LEDs used for such headlights, despite their increased power, are several times smaller in size, which is very convenient for their installation.
Interesting fact!During professional testing of the efficiency of headlights from different manufacturers and on different cars, only the Toyota Prius V managed to receive the “excellent” mark.
Thanks to this feature, designers were able to change the appearance of cars as much as possible by reducing the size of the headlights themselves. However, at the same time as LED headlights, additional systems must be installed to control the switching on and off of the high beams. For this purpose, cameras are specially installed that perform the function of monitoring the flow of oncoming cars.
Advantages of laser lighting
The advantages of such lighting, of course, include the range of light provided by laser headlights. It is impossible to find something similar among analogues, especially considering the compact design of such headlights.
Laser lighting also attracts the attention of automotive designers with its spectacular appearance, which allows you to modify the appearance of the car in different ways. If we also take into account the low energy consumption, then today laser headlights can be considered the most effective achievement of mankind.
Disadvantages of lasers used in cars
The main disadvantage of such lighting, of course, is its cost. After all, in addition to laser LEDs, additional equipment has to be installed on the car, which together amounts to a significant cost.
Thus, each type of automotive lighting can have its own advantages and disadvantages. Therefore, car enthusiasts can only rely on their own preferences, needs and financial capabilities when choosing headlights for their car. Well, you also need to be as careful as possible when purchasing such devices, since today there are a lot of fakes on the market, especially when it comes to LED headlights.
