Sealed beam

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Sealed-beam headlamp. When the lamp burns out or breaks, the whole assembly must be replaced ParHeadlamp.jpg
Sealed-beam headlamp. When the lamp burns out or breaks, the whole assembly must be replaced

A sealed beam is a type of lamp with a parabolic reflector, one or more filaments, and a glass lens sealed permanently together as a unit. Originally introduced for road vehicle headlamp service, sealed beams have since been applied elsewhere. Halogen sealed beam lamps incorporate a halogen lamp within a quartz or hard glass envelope.

Incandescent light bulb Electric light with a wire filament heated until it glows

An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light (incandescence). The filament is protected from oxidation with a glass or fused quartz bulb that is filled with inert gas or a vacuum. In a halogen lamp, filament evaporation is slowed by a chemical process that redeposits metal vapor onto the filament, thereby extending its life.

Parabola two-dimensional, mirror-symmetrical curve

In mathematics, a parabola is a plane curve that is mirror-symmetrical and is approximately U-shaped. It fits several superficially different other mathematical descriptions, which can all be proved to define exactly the same curves.

Mirror object that reflects light or sound

A mirror is an object that reflects light in such a way that, for incident light in some range of wavelengths, the reflected light preserves many or most of the detailed physical characteristics of the original light, called specular reflection. This is different from other light-reflecting objects that do not preserve much of the original wave signal other than color and diffuse reflected light, such as flat-white paint.

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Sealed beams utilize a parabolic aluminized reflector, and are thus known as "PAR" lamps. Round PAR lamp diameter is expressed in eighths of an inch, so a PAR56 lamp, for example, is 56/8" (i.e., 7 inches) in diameter. Other popular sizes are PAR30, PAR36, PAR38, PAR46, and PAR64. Rectangular PAR lamp size is expressed in millimeters, so a PAR200×142 is 200 mm wide and 142 mm tall.

The inch is a unit of length in the (British) imperial and United States customary systems of measurement. It is equal to ​1⁄36 yard or ​1⁄12 of a foot. Derived from the Roman uncia ("twelfth"), the word inch is also sometimes used to translate similar units in other measurement systems, usually understood as deriving from the width of the human thumb. Standards for the exact length of an inch have varied in the past, but since the adoption of the international yard during the 1950s and 1960s it has been based on the metric system and defined as exactly 2.54 cm.

Sealed beams are available in a variety of nominal voltage ratings, most commonly 6, 12, 24, 28, 120, and 230 V. The actual operating voltage may differ from the nominal rated voltage; for example, "12 volt" sealed beam headlamps are meant for use in automobiles with typical line voltage of 13.5 to 14.2 with the engine running.

Voltage difference in the electric potential between two points in space

Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential between two points. The difference in electric potential between two points in a static electric field is defined as the work needed per unit of charge to move a test charge between the two points. In the International System of Units, the derived unit for voltage is named volt. In SI units, work per unit charge is expressed as joules per coulomb, where 1 volt = 1 joule per 1 coulomb. The official SI definition for volt uses power and current, where 1 volt = 1 watt per 1 ampere. This definition is equivalent to the more commonly used 'joules per coulomb'. Voltage or electric potential difference is denoted symbolically by ∆V, but more often simply as V, for instance in the context of Ohm's or Kirchhoff's circuit laws.

Automotive headlamps

Sealed beam headlamps were introduced in the United States in 1939, and became mandatory from the following year until the 1984 model year. Cars prior and after that date could have a variety of shapes of headlamps, using any of a wide variety of replaceable bulbs. Between 1940 and 1956, all U.S. cars had to have two 7-inch round headlights. [1] . Each headlight had dual filaments so that one bulb provided both high and low beam. In 1957, regulations changed to allowed four sealed beam headlights (two on each side, each measuring 5 ¾ in.). Two served as low and high beam like the 7” version, while the remaining two were additional “high beam” only Lamps. This influenced the overall design of the American-made vehicles. Halogen sealed beam headlamps appeared on U.S. cars in 1978 to enable halogen technology under Federal Motor Vehicle Safety Standard 108, which at the time required all headlamps to be of sealed beam construction; eventually, halogen sealed beams came to dominate the sealed beam lamp market.

Federal Motor Vehicle Safety Standard 108 regulates all automotive lighting, signalling and reflective devices in the United States. Like all other Federal Motor Vehicle Safety Standards, FMVSS 108 is administered by the United States Department of Transportation's National Highway Traffic Safety Administration.

The limited range of standardized sealed beam headlamp sizes and shapes restricted styling options for automobiles. Replaceable-bulb headlamps provide the regulated light distributions while allowing greater design and engineering freedom. [2]

Aircraft

Aircraft landing lights are often sealed beams that have a very narrow beam spread.

Aircraft machine that is able to fly by gaining support from the air other than the reactions of the air against the earth’s surface

An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships, gliders, and hot air balloons.

Light beam

A light beam or beam of light is a directional projection of light energy radiating from a light source. Sunlight forms a light beam when filtered through media such as clouds, foliage, or windows. To artificially produce a light beam, a lamp and a parabolic reflector is used in many lighting devices such as spotlights, car headlights, PAR Cans and LED housings. Light from certain types of laser has the smallest possible beam divergence.

Building and stage lighting

In stage lighting, sealed beam lamps are often used. A common size, also used in rock concerts, as well as outdoor architectural lighting, is the parabolic aluminized reflector 64 (PAR64). PAR64 sealed beam lamps are typically available with 250, 500 or 1000 watt power ratings. The fixtures that such sealed beam lights go into are called "PAR cans". Beam spreads are designated as FL (flood), SP (spot), NSP (narrow spot), and VNSP (very narrow spot), as stamped on the back of the lamp's reflector.

Lighthouses

Sealed beam lamp arrays are also in use by modern lighthouses. [3]

Related Research Articles

Electric light A device that produces light from electricity

An electric light is a device that produces visible light from electric current. It is the most common form of artificial lighting and is essential to modern society, providing interior lighting for buildings and exterior light for evening and nighttime activities. In technical usage, a replaceable component that produces light from electricity is called a lamp. Lamps are commonly called light bulbs; for example, the incandescent light bulb. Lamps usually have a base made of ceramic, metal, glass or plastic, which secures the lamp in the socket of a light fixture. The electrical connection to the socket may be made with a screw-thread base, two metal pins, two metal caps or a bayonet cap.

Stage lighting

Stage lighting is the craft of lighting as it applies to the production of theater, dance, opera, and other performance arts. Several different types of stage lighting instruments are used in this discipline. In addition to basic lighting, modern stage lighting can also include special effects, such as lasers and fog machines. People who work on stage lighting are commonly referred to as lighting technicians or lighting designers.

Halogen lamp

A halogen lamp, also known as a tungsten halogen, quartz-halogen or quartz iodine lamp, is an incandescent lamp consisting of a tungsten filament sealed into a compact transparent envelope that is filled with a mixture of an inert gas and a small amount of a halogen such as iodine or bromine. The combination of the halogen gas and the tungsten filament produces a halogen cycle chemical reaction which redeposits evaporated tungsten to the filament, increasing its life and maintaining the clarity of the envelope. For this to happen, a halogen lamp must be operated at a higher envelope temperature than a standard vacuum incandescent lamp of similar power and operating life; this also produces light with higher luminous efficacy and color temperature. The small size of halogen lamps permits their use in compact optical systems for projectors and illumination. The small glass envelope may be enclosed in a much larger outer glass bulb for a bigger package; the outer jacket will be at a much lower, safer, temperature, protects the hot bulb from harmful contamination, and makes the bulb mechanically more similar to a conventional lamp that it might replace.

Flashlight Portable hand-held electric light


A flashlight is a portable hand-held electric light. The source of the light is usually an incandescent light bulb (lamp) or light-emitting diode (LED). A typical flashlight consists of the light source mounted in a reflector, a transparent cover to protect the light source and reflector, a battery, and a switch. These are supported and protected by a case.

Headlamp vehicle lights

A headlamp is a lamp attached to the front of a vehicle to light the road ahead. Headlamps are also often called headlights, but in the most precise usage, headlamp is the term for the device itself and headlight is the term for the beam of light produced and distributed by the device.

Bicycle lighting

Bicycle lighting is illumination attached to bicycles whose purpose above all is, along with reflectors, to improve the visibility of the bicycle and its rider to other road users under circumstances of poor ambient illumination. A secondary purpose is to illuminate reflective materials such as cat's eyes and traffic signs. A third purpose may be to illuminate the roadway so that the rider can see the way ahead. Serving the latter purposes require much more luminous flux and thus more power.

Light fixture

A light fixture, light fitting, or luminaire is an electrical device that contains an electric lamp that provides illumination. All light fixtures have a fixture body and one or more lamps. The lamps may be in sockets for easy replacement—or, in the case of some LED fixtures, hard-wired in place.

Fresnel lantern

A Fresnel lantern is a common lantern used in theatre, which employs a Fresnel lens to wash light over an area of the stage. The lens produces a wider, soft-edged beam of light, which is commonly used for back light and top light.

Stage lighting instrument

Stage lighting instruments are used in stage lighting to illuminate theatrical productions, concerts, and other performances taking place in live performance venues. They are also used to light television studios and sound stages.

Source Four PAR

The Source Four PAR is a stage lighting instrument manufactured by Electronic Theatre Controls. The name of the fixture derives from the stylistic and construction features it shares with ETC's Source Four. The suffix identifies the Source Four PAR as a parabolic aluminized reflector (PAR). It is designed and marketed as a modern, energy efficient alternative to traditional PAR fixtures used in theatrical and broadcast lighting.

Edison screw

Edison screw (ES) is a standard lightbulb socket for electric light bulbs. It was developed by Thomas Edison and was licensed in 1909 under General Electric's Mazda trademark. The bulbs have right-hand threaded metal bases (caps) which screw into matching threaded sockets. For bulbs powered by AC current, the thread is generally connected to neutral and the contact on the bottom tip of the base is connected to the "live" phase.

Multifaceted reflector

A multifaceted reflector light bulb is a reflector housing format for halogen as well as some LED and fluorescent lamps. MR lamps were originally designed for use in slide projectors, but see use in residential lighting and retail lighting as well. They are suited to applications that require directional lighting such as track lighting, recessed ceiling lights, desk lamps, pendant fixtures, landscape lighting, retail display lighting, and bicycle headlights. MR lamps are designated by symbols such as MR16 where the diameter is represented by numerals indicating units of eighths of an inch. Common sizes for general lighting are MR16 and MR11, with MR20 and MR8 used in specialty applications. Many run on low voltage rather than mains voltage alternating current so requiring a power supply.

Track lighting

Track lighting is a method of lighting where light fixtures are attached anywhere on a continuous track device which contains electrical conductors. This is in contrast to directly routing electrical wiring to individual light positions. Tracks can either be mounted to ceilings or walls, lengthwise down beams, or crosswise across rafters or joists. They can also be hung with rods from especially high places like vaulted ceilings.

Beam projector

A beam projector is a lenseless stage lighting instrument with very little beam spread. It uses two reflectors. The primary reflector is a parabolic reflector and the secondary reflector is a spherical reflector. The parabolic reflector organizes the light into nearly parallel beams, and the spherical reflector is placed in front of the lamp to reflect light from the lamp back to the parabolic reflector, which reduces spill. The result is an intense shaft of light that cannot be easily controlled or modified. Beam projectors are often used to create a godspot effect. The beam projector no longer is used to the extent that it once was, as newer fixtures and PAR lamps have created easier ways to produce the effect. A similar effect can be produced using ETC Source Four PAR fixtures with a clear lens. A snoot/top hat can be added to control spill.

The H1 is a halogen lamp designed for use in automotive headlamps and fog and driving lamps. It has also been widely applied in emergency vehicle lights.

Havells Sylvania and formerly SLI, is an international designer and manufacturer of lighting products, trading as Sylvania. It has plants throughout Europe, Asia, North Africa and Central and South America, and is one of the few lighting companies that produces both lamps and lighting fixtures. It is owned by Shanghai Feilo Acoustics Ltd., having previously been owned by the Indian electrical company Havells.

A lightbulb socket, light socket, lamp socket or lampholder is a device which mechanically supports and provides electrical connections for a compatible electric lamp. Sockets allow lamps to be safely and conveniently replaced (re-lamping). There are many different standards for lampholders, including early de facto standards and later standards created by various standards bodies. Many of the later standards conform to a general coding system in which a socket type is designated by a letter or abbreviation followed by a number.

Dive light Light used underwater by a diver

A dive light is a light source carried by an underwater diver to illuminate the underwater environment. Scuba divers generally carry self-contained lights, but surface supplied divers may carry lights powered by cable supply.

Recessed light

A recessed light or downlight is a light fixture that is installed into a hollow opening in a ceiling. When installed it appears to have light shining from a hole in the ceiling, concentrating the light in a downward direction as a broad floodlight or narrow spotlight.

References

  1. ↑ Grayen, Michael (22 April 2015). "A Brief History Of Sealed Beam Headlamps In The U.S." CARiD.com.
  2. ↑ Horst Bauer Bosch Automotive Handbook 4th Edition Robert Bosch GmbH, Stuttgart 1996 ISBN   0-8376-0333-1 page 710
  3. ↑ "The lights in Lighthouses". photographers-resource.co.uk. Retrieved 9 January 2011.
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