An IR light bulb is a type of illuminator that projects infrared light. Traditional light bulbs emit visible white light, which can be easily seen by the human eye. The light from infrared bulbs, in contrast, cannot be seen directly. This type of bulb often used in night vision, heating, communication, and health applications.
Not all light is visible. Light that can be seen by humans ranges between 400 and 700 nanometers (nm) in wavelength. The highest wavelengths in this range are produced by red colors. IR has a wavelength that is higher than red, and cannot be seen by the naked eye. The infrared spectrum is located between 0.74 micrometers and 300 micrometers in wavelength.
The rays emitted from an IR light bulb cannot be seen by people, but many devices are able to detect them. A night vision scope is one piece of technology that is designed to use infrared light. These devices amplify light from both the visible and IR ranges, and convert this light to an image that can be interpreted by humans. High-powered infrared bulbs are often used by police and military forces to covertly illuminate a scene. Personnel with night vision scopes are typically able to see more clearly, while other people see only darkness.
Infrared light bulbs are also useful for providing heat. IR waves emitted from an infrared bulb transfer energy that is absorbed by nearby objects. This absorption of energy causes an object to become warm. The heat created by IR bulbs is commonly used in saunas. Infrared heating is also used in applications such as removing ice from aircraft as well as in some industrial manufacturing.
The heat generated from infrared bulbs is believed to have health benefits. Light therapy, also known as "phototherapy," commonly uses IR heat sources to promote healing. Light in the infrared range is used to help alleviate skin disorders, and also to reduce pain caused by an injury. The medical use of infrared bulbs is often seen as more natural and holistic than using drugs.
One of the most common uses of an IR light bulb is for short-range communication. Information can be sent by pulsing the IR light source in a pattern. This is similar to a traditional light bulb being switched on and off to send Morse code. Infrared light is less prone to interference than visible light, and can be easily detected by devices in a room. Television remote controls and cellphone data ports are two examples of infrared bulbs that are used for this purpose.