Headlamp
Vehicle headlights are headlights as part of the vehicle lighting. They emit light in principle in their direction of travel and are available at almost any vehicle or in use on public roads it is compulsory in many countries.
Its main functions are
- The illumination of the area immediately in front of the route path For your own safety - identifying obstacles and
- For a fast moving and
They radiate basically white (rarely yellow ) light. Xenon light light (only in the automotive sector usual) emits bluish light from, this is considered to be white and is therefore admissible.
Motor vehicles
In road transport, a signal is given priority by the headlights image, that is, by the arrangement of the lights is other road users, the type of vehicle and direction of travel indicated. A pair of headlights, side by side on the same level, generally indicates a multi-track vehicle during a single light generally refers to a single-track vehicle.
Headlights, structural design
While single-track vehicles only have one headlight, driving lights are on wheeled vehicles (usually cars ) usually paired. They are located at the front of the vehicle; when reversing the same (white ) light is shown so that other road users the courtesy is signaled.
Headlights are mostly used as low beam; addition also high beam and fog lights can be used. In 1957, the asymmetrical dipped beam was introduced in Germany: The edge of the road of their own side of the street is much further illuminated by this asymmetry as the opposite lane. This serves to avoid glare from oncoming motorists. This division of the light intensity is thus used for traffic safety. Modern vehicles generally offer the possibility to adjust the illumination geometry, when driving in countries for which the headlights are not provided ( hand Traffic ). Previously it was necessary to the spotlight within corresponding markings, such as wedge-shaped mask off, to avoid glare.
The different lighting modes are functionally mostly in a structural unit ( low beam, high beam, parking light ) and, increasingly combined with direction indicators and installed in or under the radiator grille. This is not least the aerodynamic optimization. Fog lights are often installed in a separate housing and possible far down on the body.
Modern lighting devices often consist of a lamp which is arranged in front of a reflector. The light distribution can be designed with a combination of a parabolic mirror with an appropriately fluted headlight glass ( lens ). Enhanced Headlights possess the targeted scattering and focusing of the light specially shaped free-form reflectors that are designed with the help of non-imaging optics and do not correspond to mathematical ruled surface more. They are formed by the variation of the surface normals of the reflective surfaces corresponding to the requirements of light distribution. In this case, the reflector is often segmented into different areas. Then, each segment can satisfy a specific part of the lighting task. Clear glass headlights with headlight lens have now been largely replaced.
Alternatively it can be mounted in front of the bulb to the so-called projection lamp or projection headlights instead of a reflector and a lens. This is achieved by the geometry of the lamp and a corresponding illumination lens. These styles are used in Xenon lamps, partly also of halogen lamps.
Today's headlight systems have two assemblies that take the low beam or high beam. The projection module for the dipped beam is becoming more common side controlled by a rotary module to enable the cornering light function. In this case, the swing frame is controlled based on the lateral acceleration in the vehicle, the steering angle and the vehicle speed by a stepper motor. Motorway mode is increased by a two-stage circuit to 50 m (different measures from 90 km / h from 110 km / h). At the "extended fog light ", the light cone is rotated by 8 ° downwards and laterally to the left, which reduces the glare. Furthermore, the already known functions "active cornering light " and " cornering " integrated. In attempts a data transfer to the following car was built by the emission of light pulses at stoplights. Through the information on the braking delay can be a situation-responsive brake pressure can be generated and the risk of rear-end collisions decreases. First tests with LEDs were at 8 MB / s transmission over a distance of 130 m.
With the latest lighting technology, the adaptive high-beam assistant, the light with a camera coupled with intelligent image analysis. The camera is able to control the range of the headlamps, while achieving luminous ranges of up to 300 meters - without causing other road users to be dazzled: the light transition always terminates under the bumper of the next vehicle. When the camera recognizes no other road users more, the high beam is switched on automatically. Due to smooth transitions between all lighting scenarios arises for the driver always the optimum illumination of the road, without sudden change of light. Consequently eye can more easily adapt to the new light setting.
Pop-up headlights are installed in some sports cars. The headlight units when not in use to be sunk in the body of a lever ( e.g. Opel GT) or an electric motor. This has in addition to optical especially aerodynamic reasons.
The so-called Evil Eye is when tuning an optical extension of the hood, so that the upper edge of the headlight is covered.
Light sources
At the beginning of the automotive history patch lanterns without color filters were common side-mounted or on the hood, which were later replaced by electrically -powered lamps.
In 1908, a screening device was constructed for the then usual carbide lamps: via a Bowden cable a lever was pressed, the moved the gas flame from the focal point of the reflector.
The dual-filament lamp for combined high and low beams ( BILUX ® lamp ) was brought in 1925 by Osram on the market; from 1957 also asymmetrical passing beam ( " BILUX -AS ®" ).
The first single-filament halogen lamps of the type H1 and H3 were around 1964 on the market. 1966 Philips presented the dual-filament halogen bulb H4 for high and low beam, but only in the autumn of 1971 appeared on the market (Mercedes- Benz 350 SL). The automotive halogen lamps were initially relatively expensive: In 1976, the H4 dual-filament halogen bulb 20,40 DM and the H1 lamp 11,60 DM, accounting for 25 € or 15 € corresponds according to today's purchasing power. First, in the BMW 7 - series and there initially only as low beam came in 1991 as the moment last development headlights with gas discharge lamps (xenon light ) are used.
At the score of 2008, the adoption of LEDs is generally approved only for taillights, the approval for LED headlights is not expected from this year. The Audi R8 was the first car with full LED headlamps housed with a special permit from the EU in 2008 series. A year earlier Lexus already had fitted as standard 600 LED headlights in the LS. The latest LED technology enables a halved energy consumption compared to current halogen technology. The lifetime of the LED of 10,000 hours could be enough for a car life. In 2006, the " Intelligent Light System " Mercedes is inserted into the upper class, which provides five different lighting functions. The country light illuminates the left side of the road from large areas so that the sight is growing by about 10 m.
The lamps require an electrical supply voltage of 12 or 24 volts, the latter being common only in large vehicles such as camper vans or trucks.
Other headlight
Other types of motor vehicles headlights are working and searchlight (common for SUVs and Construction ). The use while driving is prohibited in public transport.
Some special vehicles of emergency services or the police have headlights equipment used solely for the stationary illumination of an object or area.
Tarnlichter are in their luminosity and scattering modified lighting equipment at the front and at the rear of military vehicles. They have a light output that is significantly limited by horizontal slit-shaped openings (essays ) or directed perpendicular to the roadway lights. The minimal illumination of the road, these lights serve the camouflage from the enemy. Certain Tarnlichter also come equipped with red color filters.
Headlights on powered two-wheelers
Headlights of motorized two-wheelers are almost always combined with high beam and mounted centrally above the wheels with the longitudinal axis. Motorcycles have rarely more than a spotlight. If, however, all other pairs be (preservation of image signal ) in Germany. Searchlight on two-wheelers are not allowed in Germany in public transport. In Germany, the low beam must be switched on at any time. Reason alone is the road safety because of the remotely difficult to detect contour of two-wheelers. Parking lights are only available on high-quality models and not prescribed.
Others
As the regular daytime running headlights or special daytime running lights can be used. In some countries it is compulsory to drive even during the day with the headlights. The benefits of day - light duty for motor vehicles is controversial in Germany.
Motor vehicle driver can fade in (short term the high beams ) to announce an overtaking maneuver to point ( in Germany only outside built-up areas ) or a hazard. Furthermore, there is the so-called intermittent light, which is used when riding with special signals in some German states on emergency vehicles. This is the high beam automatically switched on and off ( frequency about 1 Hz). Another variant is the flasher unit. Here are lit high beam and fog lights alternately. Both variants are not permitted, as they are different from the light device specified in the Road Traffic Licensing Regulations. However, may be waived by a waiver thereof. Of this use has been made, especially in northern Germany. The Federal-State Technical Committee Technical Motor beings has spoken out against the flasher because the permissible lighting equipment sufficient to comply with the sovereign functions. In a letter to the top road authorities of the countries of 19 March 2001 (Case No. 33/36.25.61/001 BM 2001), the Federal Ministry of Transport has supported the decision of the Committee bill and prohibits the use of and the granting of authorizations for Spring light. In addition, the demolition of existing facilities has been arranged. The arrangement was in many places but not or only partially followed.
In some countries are basically replacement bulbs carry. In general, this applies to Spain, Serbia, Macedonia and Montenegro. In Croatia, Slovakia and Russia replacement lamps are required with the exception of LEDs and xenon lamps. Recommended spare bulbs for France, Portugal, Hungary, Slovenia, Czech Republic, Norway and the Netherlands, where this provision is partially used only on domestic vehicles. Carrying matching set of spare bulbs is generally useful when replacement is hard to come by. In many vehicles, an exchange only in the workshop with a greater effort. With the addition of 07 to ECE Regulation R -48 2006 newer vehicles but must be constructed in August that a bulb replacement without tools is possible .. In Xenon lamps replaced in the garage is still required.
National Features
In France, were prescribed for automobiles from 1937-1993 yellow car headlights; since 1993 they are optional. In most countries, however (to date) white headlamps are required.
In Denmark, Sweden, Norway and Finland is prescribed, the headlights when driving all day on.
Rail vehicles
Rail vehicles usually carry one to three bright white headlights head to the side. In Germany, Austria and Switzerland as well as in some other countries regularly in the form of the three- light spike signal.
Vehicles that can go in both directions, have a complete lighting system for forward and reverse travel at both ends. Since the peak signal simply warn you of an approaching rail vehicle and is not intended to improve visibility for the train driver, it is often not particularly bright Newer locomotives have additional driving lamps with which the route can be illuminated at greater distances.
Aircraft
Aircraft operate headlights for the launch and landing. Small aircraft have one or two, large aircraft have two or more lights.
Airliners usually have their own spotlight for taxiing (Taxi Lights) and for landing ( Landing Lights ). Landing lights are stronger and remain lit up (like the high beams at cars) would on the ground blind the pilots of other aircraft. Some aircraft have additional downward radiant "Flare Lights" for better illumination of the runway during landing (eg deHavilland Dash 8). Larger aircraft are often equipped with " turnoff lights" for better lateral illumination of the runway exits.
Traffic and larger military aircraft often switch from an altitude below 3000 m (10,000 ft) at each visibility condition, the landing lights in order for others to optimize their visibility and to illuminate the environment, in particular the slopes. This applies, among others, for air traffic control ( approach) to other road users (pilots ) and also for birds (see Bird strike ).
Specific circuits ( Pulse Light (R)) on and off alternately enable the left and right headlamps to enhance the visibility. Some light aircraft have their own, suitable for continuous operation " recognition lights" ( roughly comparable to the daytime running lights of a car ).
Since headlights have an aerodynamically unfavorable form, they are often designed retractable. This can be done either by mounting the retractable landing gear retraction or by own. Alternatively headlights are mounted under aerodynamic fairings. When mounted at the wing leading edge, however, results from the fact an interruption of the de-icing.
Some military aircraft and rescue, military and police helicopters are equipped with searchlights. The helicopters mentioned have partly Infrared spotlight on board serving the illumination of observed objects for the infrared camera.
Watercraft
Position lights of relatively low luminosity are used on vessels for the regular ride. If necessary, search and work lights or deck lights are used icebreaker use high-intensity spotlight to illuminate the driving route in the ice at night.
On military ships Morse headlights are partly still in use today. However, they are used for communication with each other and not the transport.
Bicycles
→ Main article: Bicycle Lighting
An important component of the vehicle lighting of bicycles are the headlights. Each bicycle in Germany must be equipped with a bicycle headlight. It is immaterial whether the visibility require ( Exceptions exist for certain racing bikes ). They are equipped with incandescent lamps or LEDs.
The energy supply is depending on the system either via a bicycle dynamo or batteries. The voltage ordinary headlight is 6 volts, the maximum power of 2.4 watts. In Germany, the 10 -Lux control the bike Regulation For headlamps with LED light source, the minimum requirement for the optical power in Austria. For battery-operated headlights Aufstecksätze are used very frequently.