Infrared lamps are electrical devices which emit

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

radiation. Infrared lamps are commonly used in radiant heating for industrial processes and building heating. Infrared

LED A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresp ...

s are used for communication over optical fibers and in

remote control A remote control, also known colloquially as a remote or clicker, is an consumer electronics, electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operat ...

devices. Infrared lamps are also used for some

night vision device A night-vision device (NVD), also known as a night optical/observation device (NOD) or night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision. The ...

s where visible light would be objectionable. Infrared lamp sources are used in certain scientific and industrial instrument for chemical analysis of liquids and gases; for example, the

pollutant A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effect, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oi ...

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...

in air can be measured using its infrared absorption characteristics. IR radiant energy emitted by lamps cover a wide spectrum of wavelengths, ranging from 0.7 μm ( micrometers) to a longer wavelength of 400 μm.

Types

Incandescent light bulb An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a #Filament, filament until it incandescence, glows. The filament is enclosed in a ...

s use a

tungsten Tungsten (also called wolfram) is a chemical element; it has symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first ...

filament heated to high temperature to produce visible light and, necessarily, even more infrared radiation. Round bulbs, often tinted red to reduce visible light, provide infrared radiant heat suitable for warming of people or animals, but the power density available is low. The development of quartz halogen linear lamps allowed much higher power density up to 200 watts/inch of lamp (8 w/mm), useful for industrial heating, drying and processing applications.Raymond Kane, Heinz Sell (ed.) ''Revolution in Lamps: A Chronicle of 50 Years of Progress, Second Edition'', CRC Press, 2001 , Chapter 3 ''The T3 Quartz Infrared Lamp'') By adjusting the voltage applied to incandescent lamps, the spectrum of the radiated energy can be made to reduce visible light and emphasize infrared energy production. Different wavelengths of infrared radiation are differently absorbed by different materials. Some applications use the heat generated by the standard incandescent lamps, such as incubators, brooding boxes for

poultry Poultry () are domesticated birds kept by humans for the purpose of harvesting animal products such as meat, Eggs as food, eggs or feathers. The practice of animal husbandry, raising poultry is known as poultry farming. These birds are most typ ...

, heat lights for

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

tanks, novelty lamps such as

lava lamp A lava lamp is a decorative lamp that was invented in 1963 by British entrepreneur Edward Craven Walker, the founder of the lighting company Mathmos. It consists of a bolus of a special coloured wax mixture inside a glass vessel, the remainde ...

s, and the

Easy-Bake Oven The Easy-Bake Oven is a working toy oven introduced in 1963 and manufactured by Kenner and later by Hasbro. The original toy used a pair of ordinary incandescent light bulbs as a heat source; current versions use a true heating element. Kenner ...

toy. Heat lamps may have a red coating to reduce the visible light emitted. Solid-state light emitting diodes can be produced to be efficient sources of near-monochromatic infrared energy. Such sources can be rapidly

modulated Signal modulation is the process of varying one or more properties of a periodic waveform in electronics and telecommunication for the purpose of transmitting information. The process encodes information in form of the modulation or message ...

for communication systems and control signals. A light emitting diode can be closely coupled to an optical fiber, allowing infrared signals to be sent up to scores of kilometres without amplification.

Heating

Infrared heating uses infrared lamps, commonly called heat lamps, to transmit infrared radiation to the body that is being heated. When a body with a large surface area needs to be heated, an array of infrared lamps is often used. The lamp commonly contains an incandescent bulb that produces infrared radiation. Infrared lamps have many industrial applications including curing coatings and preparing plastic for forming, commercial applications such as cooking and browning food, and personal applications such as providing heat (especially in bathrooms and for pets) as well as for commercial and industrial heating.

Communication

IR data transmission is also employed in short-range communication among computer peripherals and

personal digital assistant A personal digital assistant (PDA) is a multi-purpose mobile device which functions as a personal information manager. Following a boom in the 1990s and 2000s, PDAs were mostly displaced by the widespread adoption of more highly capable smar ...

s. These devices usually conform to standards published by

IrDA IrDA is a wireless standard designed for exchanging data using infrared (IR). Infrared ports for this purpose have been implemented in portable electronic devices such as mobile telephones, laptops, cameras, printers, and medical devices. The mai ...

, the Infrared Data Association. Remote controls and IrDA devices use infrared

light-emitting diode A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corre ...

s (LEDs) to emit infrared radiation which is focused by a plastic

lens A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'') ...

into a narrow beam. The beam is

, i.e. switched on and off, to encode the

data Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...

. The receiver uses a

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

photodiode A photodiode is a semiconductor diode sensitive to photon radiation, such as visible light, infrared or ultraviolet radiation, X-rays and gamma rays. It produces an electrical current when it absorbs photons. This can be used for detection and me ...

to convert the infrared radiation to an electric current. It responds only to the rapidly pulsing signal created by the transmitter, and filters out slowly changing infrared radiation from ambient light. Infrared communications are useful for indoor use in areas of high population density. IR does not penetrate walls and so does not interfere with other devices in adjoining rooms. Infrared is the most common way for

s to command appliances.

References

{{Artificial light sources Types of lamp

Types

Heating

Communication

See also

References