Backlit Screen - traducción al español
![electroluminescent]] backlight switched on (top) and switched off (bottom)](https://commons.wikimedia.org/wiki/Special:FilePath/Backlit LCD display.jpg?width=200 "electroluminescent]] backlight switched on (top) and switched off (bottom)")
![The poster shop at [[Heart Mountain War Relocation Center]] was operated by Japanese-American internees who used the silkscreen method to print information for the entire center (January 1943)](https://commons.wikimedia.org/wiki/Special:FilePath/Heart Mountain Relocation Center, Heart Mountain, Wyoming. Members of the Poster Shop Staff at the . . . - NARA - 539255.jpg?width=200 "The poster shop at [[Heart Mountain War Relocation Center]] was operated by Japanese-American internees who used the silkscreen method to print information for the entire center (January 1943)")
![macro photo]] of a screen print with a photographically produced [[stencil]]. The ink will be printed where the stencil does not cover the substrate](https://commons.wikimedia.org/wiki/Special:FilePath/Ssc.jpg?width=200 "macro photo]] of a screen print with a photographically produced [[stencil]]. The ink will be printed where the stencil does not cover the substrate")
Wikipedia
A backlight is a form of illumination used in liquid-crystal displays (LCDs). As LCDs do not produce light by themselves—unlike, for example, cathode ray tube (CRT), plasma (PDP) or OLED displays—they need illumination (ambient light or a special light source) to produce a visible image. Backlights illuminate the LCD from the side or back of the display panel, unlike frontlights, which are placed in front of the LCD. Backlights are used in small displays to increase readability in low light conditions such as in wristwatches, and are used in smart phones, computer displays and LCD televisions to produce light in a manner similar to a CRT display. A review of some early backlighting schemes for LCDs is given in a report Engineering and Technology History by Peter J. Wild.
Simple types of LCDs such as in pocket calculators are built without an internal light source, requiring external light sources to convey the display image to the user. Most LCD screens, however, are built with an internal light source. Such screens consist of several layers. The backlight is usually the first layer from the back. Light valves then vary the amount of light reaching the eye, by blocking its passage in some way. Most use a fixed polarizing filter and a switching one, to block the undesired light.
