IR lamps, or infrared lamps, are any light sources that provide light in a spectrum or wavelengths longer than visible red. This technology has a wide range of uses, including chemical and paint reactions, thermal or heat imaging and medical uses. It is generally inexpensive to produce these lamps, and infrared exposures to humans are generally safe.
All objects radiate heat in the infrared region, even in a vacuum. IR lamps can be used to illuminate cooler objects or objects at a distance by sending out a specific wavelength of infrared light. A detector or camera can see the reflected light and show objects in the dark without the need for visible light.
Different frequencies of IR lamps are used for a diverse range of applications. They can cure paint on automobiles or other parts, heat the skin or food, and send voice or data communications. The effects of these lamps are normally best at shorter ranges, with the exception of IR lasers for communications. Infrared lasers can connect data towers where it is not possible to bury fiber optic cables.
Military uses of IR lamps steadily grew through the 20th century as warfare became increasingly stealthy. Passive systems can detect body heat against cooler backgrounds without the need for illumination. In warmer areas or cities with many heat sources, the lamps may be used with sensing equipment to provide better night visibility. The lights are invisible to the human eye, and can be mounted on vehicles, ships or aircraft as needed.
Far-infrared frequencies have been investigated for medical uses. Research has shown that application of far-IR can relieve pain and promote healing in some patients. Medical devices must be manufactured with strict frequency tolerances, because the wrong frequency can burn the patient, rather than heal them.
IR lamps can also be used as heat sources. Heating equipment using infrared is widely used in restaurants, food service, and small space heating applications such as bathrooms. It is effective and relatively inexpensive, and short-term exposure to the light wavelengths used for heating does not cause injury. Home space heating with infrared is possible, but operating costs can be high and the room is heated indirectly by absorption of the IR energy into room objects.
Historians and art experts can use infrared lamps to research documents and paintings. IR light can expose secondary images or text that may be hidden beneath a printed document or artwork. Special imaging equipment is used to view the reflected light and observe any underlying images.
Light-emitting diodes, or LEDs, can be manufactured to transmit infrared light. These consume very little power and take up little space. They have been replacing incandescent IR fixtures since the late 20th century and can be found in many consumer and commercial security and night vision systems.