A mirror with an optical thin film that transmits infrared rays and reflects visible light.
Because it uses a dielectric multilayer film that does not absorb heat, it efficiently transmits heat rays and reflects visible light. It has the characteristic of transmitting only the long wavelength band.
Substances with different refractive indices are deposited alternately and in multiple layers on glass with a thickness of "λ (wavelength)/4" by vacuum deposition.
"Mirrors that transmit near-infrared rays (heat waves) that raise the temperature of irradiated objects and efficiently reflect visible light are used as mirrors (dental mirrors) used in dentists' treatment tables, as lighting fixtures for operating tables, museums and LCD projectorsetc. It is used in many fields ."