Infrared rays are used in physical therapy.
Flashing LEDs and photodiodes are used ubiquitously in remote controls, automation systems, security systems, some mobile phones (infrared), etc. The infrared rays do not distract the person's attention because of its invisibility.
Interestingly, the infrared remote control domestic easily fixed with a digital camera.
Infrared emitters are used in industry for drying paint surfaces. Infrared drying method has significant advantages over conventional, convection method. The first is, of course, the economic effect. Speed and power, used in infrared drying less the same performance with traditional methods.
Using infrared radiation sterilizing foods to disinfect.
History of infrared radiation
Infrared radiation was discovered in 1800 by English astronomer William Herschel. Pursuing the study of the Sun, Herschel was looking for a way to reduce heating tool with which observations were made. Defining by thermometers actions of different parts of the visible spectrum, Herschel discovered that the "high heat" is for a strong red color and possibly "the apparent refraction." This research laid the foundation for the study of infrared radiation.
Very strong infrared radiation in areas of high heat can dry out the mucous membrane of the eye. The most dangerous when not accompanied by emission of visible light. In such places need to wear special goggles for the eyes.