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Parabolic aluminized reflector
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Parabolic aluminized reflector
A parabolic aluminized reflector lamp (PAR lamp or simply PAR) is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. It produces a highly directional beam. Usage includes theatrical lighting, locomotive headlamps, aircraft landing lights, and residential and commercial recessed lights ("cans" in the United States).
Many PAR lamps are of the sealed beam variety, with a parabolic reflector, one or more filaments, and a glass or plastic 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.
A PAR lamp consists of a light source, with lens and a parabolic reflector with a smooth aluminium surface determining the spread of the beam. The most common sealed beam type combines these three elements into an integral unit. The light source usually approximates a point source that can be focused on; tungsten filaments and halogen lamps are common, but some theatrical usage that requires a higher color temperature may use hydrargyrum medium-arc iodide (HMI) instead.
PAR lamps come in a variety of standardized sizes. The size of a round PAR lamp is expressed as the nominal diameter of the mouth of the reflector, in eighths of an inch, so the approximate nominal lamp bell diameter in inches can be found by dividing the PAR size by 8. A PAR56, for example, is 56 eighths of an inch (7 inches) in diameter; a PAR36 is 36 eighths (4.5 inches) in diameter, and so on. Similarly, the diameter in millimeters can be found by multiplying the PAR designation by 3.175. For example, a PAR16 lamp is approximately 2 inches or 50.8 mm in diameter.
The size of rectangular PAR lamps is expressed as the letters REC followed by the reflector's mouth height, the letter "X", and the reflector's mouth width, with both dimensions in millimeters. For example, REC142X200 lamps are 142 mm high and 200 mm wide.
Depending on the parabolic reflector geometry, the configuration of the filament and its placement within the paraboloid, PAR lamps can achieve a wide range of beams, from narrow spot to wide flood. The following suffixes are commonly used with PAR lamps to indicate their beam width: PAR lamps are also manufactured to produce beam patterns specific to the needs of particular applications, such as low-beam and high-beam headlamps and fog and driving lights for vehicles, and warning lamps for school buses.
The suffixes given are for 1000-Watt PAR64 lamps only. The focused beam can be oval and is sometimes specified in two numbers.
In the United States of America, sealed-beam headlamps were introduced in 1939, becoming standard equipment across all American-market vehicles starting in 1940 and remaining the only type allowed for almost four and a half decades, until the 1984 model year. Before and after those years, vehicles could have model-specific, non-standard-shape headlamps, using any of a wide variety of replaceable light bulbs.
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Parabolic aluminized reflector
A parabolic aluminized reflector lamp (PAR lamp or simply PAR) is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. It produces a highly directional beam. Usage includes theatrical lighting, locomotive headlamps, aircraft landing lights, and residential and commercial recessed lights ("cans" in the United States).
Many PAR lamps are of the sealed beam variety, with a parabolic reflector, one or more filaments, and a glass or plastic 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.
A PAR lamp consists of a light source, with lens and a parabolic reflector with a smooth aluminium surface determining the spread of the beam. The most common sealed beam type combines these three elements into an integral unit. The light source usually approximates a point source that can be focused on; tungsten filaments and halogen lamps are common, but some theatrical usage that requires a higher color temperature may use hydrargyrum medium-arc iodide (HMI) instead.
PAR lamps come in a variety of standardized sizes. The size of a round PAR lamp is expressed as the nominal diameter of the mouth of the reflector, in eighths of an inch, so the approximate nominal lamp bell diameter in inches can be found by dividing the PAR size by 8. A PAR56, for example, is 56 eighths of an inch (7 inches) in diameter; a PAR36 is 36 eighths (4.5 inches) in diameter, and so on. Similarly, the diameter in millimeters can be found by multiplying the PAR designation by 3.175. For example, a PAR16 lamp is approximately 2 inches or 50.8 mm in diameter.
The size of rectangular PAR lamps is expressed as the letters REC followed by the reflector's mouth height, the letter "X", and the reflector's mouth width, with both dimensions in millimeters. For example, REC142X200 lamps are 142 mm high and 200 mm wide.
Depending on the parabolic reflector geometry, the configuration of the filament and its placement within the paraboloid, PAR lamps can achieve a wide range of beams, from narrow spot to wide flood. The following suffixes are commonly used with PAR lamps to indicate their beam width: PAR lamps are also manufactured to produce beam patterns specific to the needs of particular applications, such as low-beam and high-beam headlamps and fog and driving lights for vehicles, and warning lamps for school buses.
The suffixes given are for 1000-Watt PAR64 lamps only. The focused beam can be oval and is sometimes specified in two numbers.
In the United States of America, sealed-beam headlamps were introduced in 1939, becoming standard equipment across all American-market vehicles starting in 1940 and remaining the only type allowed for almost four and a half decades, until the 1984 model year. Before and after those years, vehicles could have model-specific, non-standard-shape headlamps, using any of a wide variety of replaceable light bulbs.
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