A ray of light that falls on the surface of a lens — or any other object. The “angle of incidence” is the angle made by the ray with a perpendicular to the surface.
Abbreviated IR. The region of the electromagnetic spectrum between the long-wavelength extreme of the visible spectrum (~700nm) and the shortest microwaves (~1mm).
[box]Note: the International Commission on Illumination (CIE) recommended the following division:
IR-A: 700nm – 1400nm
IR-B: 1400nm – 3000nm
IR-C: 3000nm – 1mm[/box]
The magnitude of radiant energy (light) per unit, such as time or reflecting surface.
The viewing condition within which the eye is exposed to all or part of a laser beam.