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Optical computer mice use LEDs as a light source for the miniature camera within the mouse. LEDs are useful for machine vision because they provide a compact, reliable source of light. LED lamps can be turned on and off to suit the needs of the vision system, and the shape of the beam produced can be tailored to match the system's requirements.
The wavelength of the light emitted is a function of the band gap of the semiconductor material used; materials such as gallium arsenide, and others, with various trace doping elements, are used to produce different colors of light. Another type of LED uses a quantum dot which can have its properties and wavelength adjusted by its size. Light ...
Green electroluminescence from a point contact on a crystal of SiC recreates Round's original experiment from 1907. Close-up of a 1 watt red power led. The first Light-Emitting Diode was created in 1927 by Russian inventor Oleg Losev, [1] and used silicon carbide as a semiconductor.
Often more than half of the emitted light is reflected back at the LED-package and package-air interfaces. The reflection is most commonly reduced by using a dome-shaped (half-sphere) package with the diode in the center so that the outgoing light rays strike the surface perpendicularly, at which angle the reflection is minimized. Substrates ...
The first LEDs emitted light in a very narrow band of wavelengths, of a color characteristic of the energy band gap of the semiconductor material used to make the LED. LEDs that emit white light are made using two principal methods: either mixing light from multiple LEDs of various colors, or using a phosphor to convert some of the light to ...
An organic light-emitting diode (OLED), also known as organic electroluminescent (organic EL) diode, [1] [2] is a type of light-emitting diode (LED) in which the emissive electroluminescent layer is an organic compound film that emits light in response to an electric current.
While Franck and Hertz were unaware of it when they published their experiments in 1914, [19] in 1913 Niels Bohr had published a model for atoms that was very successful in accounting for the optical properties of atomic hydrogen. These were usually observed in gas discharges, which emitted light at a series of wavelengths.
Candoluminescence, is light emitted by certain materials at elevated temperatures, which differs from the blackbody emission expected at the temperature in question. Mechanoluminescence, a result of a mechanical action on a solid Triboluminescence, generated when bonds in a material are broken when that material is scratched, crushed, or rubbed