The device and types of headlights of the car

The central place in the vehicle lighting system is occupied by the front headlamps (headlights). They ensure the safety of journeys in the evening and at night by illuminating the road in front of the vehicle and informing other drivers when a vehicle is approaching.

Front headlights: structural elements

Headlights have been refined over the decades. Until the end of the twentieth century, round headlights of the searchlight type were installed on cars. However, as the ergonomics and aerodynamics of the body changed, new solutions arose: round headlights did not allow creating smooth, streamlined body lines. Therefore, designers and constructors began to introduce new, more attractive forms that are not inferior in terms of light qualities and characteristics.

A modern headlamp combines several devices in one:

• headlights of low and high beam;
• parking lights;
• direction indicators;
• Daytime Running Lights.

A single design is called a block headlamp. In addition to it, fog lights (PTF) can be installed on the front of the car, ensuring travel safety in poor visibility conditions.

dipped headlights

Depending on road conditions, dipped or main beam headlamps can be used at night.

The dipped headlights provide illumination of the roadway 50-60 meters in front of the vehicle. The headlights also illuminate the right shoulder.

Dipped beam should not cause discomfort to drivers of oncoming vehicles. If your car blinds other motorists, then the headlights need adjustment.

In the world, there are two systems of light distribution of a stream - European and American. Each of them has its own characteristics in the structure and principles of beam formation.

The filament in the headlights of American cars is located slightly above the horizontal plane. The luminous flux is divided into two parts, one of which illuminates the road and the side of the road, and the second is directed towards oncoming traffic. To prevent the headlights from dazzling drivers, the depth of the reflector that forms the lower part of the light beam changes.

In European vehicles, the filament is located above the focus of the reflector and is obscured by a special screen that prevents the light flux from entering the lower hemisphere. Thanks to this system, European-style headlights are more comfortable for oncoming motorists. The luminous flux is directed forward and downward, directly onto the road surface in front of the vehicle.

High beam headlights

The main beam of the headlights is distinguished by the highest intensity and brightness of the luminous flux, snatching 200-300 meters of the roadway from the darkness. It provides the maximum range of road illumination. But it can be used only if there are no other cars in the line of sight in front of the car: too bright light blinds drivers.

The adaptive lighting system, which is installed as an additional function on some modern cars, helps to reduce the negative effect of high beam.

Headlight device

Regardless of the type of headlights, there are three main elements that ensure the operation of optics.

Light source

The light source is the main element of any headlight. The most common source in front headlamps is halogen bulbs. Relatively recently, they were competing with xenon lamps, and even later - LED devices.

Reflector

The reflector is made of glass or plastic with a small aluminum dusting. The main task of the element is to reflect the light fluxes emanating from the source and to increase their power. Correctors and light screens help direct the beam of light in a given direction.

According to their characteristics, reflectors can be divided into three main types.

1. Parabolic reflector. The most affordable option, characterized by its static design. Headlights with such a device cannot be corrected by changing the brightness, intensity and direction of the light rays.
2. Free-form reflector. It has several zones that reflect individual parts of the light beam. The light in these headlights remains static, but when scattered, there is much less light loss. Also, the headlights with a free-form reflector are more comfortable for other drivers.
3. An ellipsoidal reflector (lens optics) is the most expensive, but at the same time the highest quality option, eliminating light loss and glare of other drivers. The scattered light stream is amplified using an elliptical reflector, and then redirected to a second focus - a special partition that collects light again. From the flap, the flux is re-scattered towards the lens, which collects light, truncating or redirecting it. The main disadvantage of the lens is that its stability may decrease with active use of the car. This, in turn, will lead to malfunctions or loss of light. It will be possible to eliminate the defect only with the help of a professional lens correction performed in a car service.

Diffuser

The light diffuser in the car is the outer part of the headlight, made of glass or transparent plastic. On the inner side of the diffuser there is a system of lenses and prisms, the size of which can vary from a millimeter to several centimeters. The main task of this element is to protect the light source from external influences, to scatter the beam by directing the flow in a given direction. Different shapes of diffusers help to regulate the direction of light.

Types of light sources

In modern cars, several types of headlights can be distinguished, depending on the light sources used.

Incandescent lamps

The simplest and most affordable, but already outdated source is incandescent lamps. Their work is provided by a tungsten filament located in an airless glass bulb. When voltage is applied to the lamp, the filament heats up and a glow begins to emanate from it. However, with constant use, tungsten tends to evaporate, which ultimately leads to rupture of the filament. As new technologies developed, incandescent bulbs could not stand the competition and were no longer used in automotive optics.

Halogen lamps

Despite the fact that the principle of operation of halogen lamps is similar to incandescent lamps, the service life of halogen lamps is several times longer. Vapors of halogen gas (iodine or bromine) pumped into the lamp help to increase the duration of the lamps, as well as to increase the level of illumination. The gas interacts with the tungsten atoms on the filament. Evaporating, tungsten circulates through the bulb, and then, connecting with the filament, again settles on it. This system extends lamp life up to 1 hours or more.

Xenon (gas discharge) lamps

In xenon lamps, light is generated by heating the gas under high voltage. However, the lamp can be ignited and powered only with the help of special equipment, which increases the total cost of the optics. But the cost is justified: xenon headlights can last 2 hours or more.

The most common head light system uses bi-xenon headlights that combine low and high beams.

LED lamp

LEDs are the most modern and popular light source. The service life of such lamps reaches 3 or more hours. With the lowest energy consumption, LEDs are capable of providing sufficient illumination. Such lamps are actively used in both external and internal vehicle lighting systems.

LEDs have been used in the front headlights since 2007. To ensure the desired level of light brightness, several segments of LED sources are installed in the headlights at once. In some cases, headlights can include up to two to three dozen LEDs.

Innovative developments

It is possible that in the future modern light sources will be superseded by new developments. For example, laser headlights are an innovative technology, which was first used in the BMW i8. The headlamp uses a laser as a source of illumination, which shines onto a phosphor-coated lens. The result is a bright glow, directed by the reflector onto the roadway.

Laser lifespan is comparable to LEDs, but brightness and power consumption are much better.

The cost of a set of laser headlights starts from 10 euros. This price is comparable to the cost of a budget car.

Another modern development is matrix headlights based on LED light sources. Depending on the traffic situation, the car can automatically adjust the operation of each section of the LEDs separately. This setting helps ensure excellent lighting even in difficult conditions of poor visibility.

Methods for controlling the head light

The way the front headlights are switched on in a car depends on the make, model and equipment of the car. In budget options, a manual way of controlling the optics is provided. The driver uses a dedicated switch that can be installed under the steering wheel or on the dashboard.

In more modern and expensive models, there is a device that automatically turns on the headlights under certain conditions. For example, optics can start working at the moment the engine is started. Sometimes the headlight switching device is combined with a rain sensor or special elements that react to the light level.

As with other elements of the car, the headlights continue to be improved. They acquire not only a bright and technological design, but also improved light characteristics. However, the main task of headlights remains unchanged and is to ensure the safety of the driver, his passengers and other road users in the dark.