The basic principle of infrared receiving head

We know that the eyes can see the visible wavelength from long to short, followed by red, orange, yellow, green, green, blue, and purple. The red light wavelengths in the range of 0.62 ~ 0.76 microns; Purple light wavelength in the range of 0.38 ~ 0.46 microns. Is shorter than violet light wavelength of light called ultraviolet ray, wavelength than red light has long called infrared light. Infrared remote control is the use of wavelength for near infrared between 0.76 ~ 1.5 microns to transmit control signals.