Infrared, or IR, is the portion of the electromagnetic (EM) spectrum between visible color and microwaves. Below the violet end of the rainbow lies ultraviolet, commonly seen in black light bulbs; above the red end of the spectrum, infrared emits as thermal or heat energy. Numerous types of IR bulbs radiate this band, and they're commonly known as heat lamps. Types of IR bulbs include quartz, halogen, clear or red-coated, incandescent, and ceramic varieties.
Heat energy of infrared can be seen in the rainbow-colored images of thermal photography. With wavelengths longer than visible light, it falls between 0.74 micrometers (¦Ì) and 300 ¦Ì of the EM spectrum. Bulbs are commonly used for infrared heating applications.
Such uses can include infrared saunas and heat therapy. These are also the red or orange lights that glow over fast food to keep it warm. IR heating may be used for industrial processes like plastic welding or print drying. Other common applications involve the use of infrared lamps for incubators and animal rehabilitation.
The warmest temperatures are produced by infrared halogen bulbs. These long-lasting bulbs use tungsten elements to emit light with a high color temperature. Flood lamps coated with red surfaces filter white light to optimize infrared radiation. Like their clear-coated counterparts, these bulbs are designed to minimize regular light and emit the maximal amount of heat radiation.
Various infrared bulbs may be housed on stands or mounts for use in therapy and patio heating. Large incandescent bulbs may be wrapped in metallic finishes to help reflect heat. These flood-style infrared bulbs, sometimes called globes, often sport a frosted color, and range in the hundreds of watts.
Found in home security, infrared illuminators rely on lasers, diodes, and lamps. These light sources provide colorful IR illumination on subjects caught in IR security cameras. The benefit of this type of illumination is that it is invisible to the eye; nighttime subjects light up clear as day, thanks to heat-producing security IR bulbs and illuminators.
Nocturnal bulb varieties also serve incubators and reptile cages; these may be simple, red-hued incandescent bulbs or long-lived ceramic globes of lower household wattages. Ceramic varieties give off heat but no light and allow animals to maintain a more natural daily cycle. IR bulbs for neonates or brooding may be aided by use of a thermostat to monitor temperatures.
Generally speaking, IR bulbs can provide efficient heating for low energy cost. Gas-powered IR lamps often do duty in industrial spaces, while electric IR lamps work in residences. Colors can vary. As they are under greater pressure, IR bulbs are relatively easier to break than other types of bulbs, so some IR products feature shatter-resistant construction. Many of these bulb varieties are able to fit standard fixtures.