Photonics Dictionary

AC thin film electroluminescent (ACTFEL) display devices are a type of flat-panel display technology that uses electroluminescence to produce visible light. Structure: They consist of a thin...

The perceived brightness of an object being viewed at some distance, especially through an optical instrument.

An instrument for measuring the brightness (luminance) of a scene. It may be a spot meter, covering an area of a degree or less, or an averaging meter, covering a broad area of the scene. Brightness...

Colorimetry is the science and technology of quantitatively describing and measuring colors. It involves the precise evaluation of color attributes such as hue, saturation, and brightness, using...

An instrument used to measure the light from a scene to be photographed and to indicate the camera lens and shutter settings required to expose the film correctly. The exposure time required in a...

An optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical filters are used to control the spectral content of light in various...

A pentaprism is a five-sided glass prism used in optical devices, particularly in SLR cameras, to deviate the path of light by 90 degrees and ensure that the image seen through the viewfinder is...

Photometry is the branch of science that deals with the measurement of light, particularly in terms of its intensity and the way the human eye perceives it. It involves the quantification of visible...

An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small telescope, and a mirror in the focal plane reflects an internal illuminated surface...