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LCD projector
An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern equivalent of the slide projector or overhead projector. To display images, LCD (liquid-crystal display) projectors typically send light from a metal-halide lamp through a prism or series of dichroic filters that separates light to three polysilicon panels – one each for the red, green and blue components of the video signal. As polarized light passes through the panels (combination of polarizer, polysilicon LCD panel and analyzer), individual pixels can be opened (made transparent controlled by electricity) to allow light to pass or closed (made opaque controlled by electricity) to block the light. The combination of open and closed pixels can produce a wide range of colors and shades in the projected image.
Metal-halide lamps are used because they output an ideal color temperature and a broad spectrum of color. These lamps also have the ability to produce an extremely large amount of light within a small area; current projectors average about 2,000 to 15,000 American National Standards Institute (ANSI) lumens.
Other technologies, such as digital light processing (DLP) and liquid crystal on silicon (LCOS) are also becoming more popular in modestly priced video projection.
Because they use small lamps and the ability to project an image on any flat surface, LCD projectors tend to be smaller and more portable than some other types of projection systems. Even so, the best image quality is found using a blank white, grey, or black[citation needed] (which blocks reflected ambient light) surface, so dedicated projection screens are often used.
Perceived color in a projected image is a factor of both projection surface and projector quality. Since white is more of a neutral color, white surfaces are best suited for natural color tones; as such, white projection surfaces are more common in most business and school presentation environments.
However, darkest black in a projected image is dependent on how dark the screen is. Because of this, some presenters and presentation-space planners prefer gray screens, which create higher-perceived contrast. The trade-off is that darker backgrounds can throw off color tones. Color problems can sometimes be adjusted through the projector settings, but may not be as accurate as they would on a white background.
A projector's throw ratio is used when installing projectors to control the size of the projected display. For example, if the throw ratio is 2:1 and the projector is fourteen feet away from the screen, then the display width will be seven feet.
Early experiments with liquid crystals to generate a video image were done by John A. van Raalte at the RCA-Laboratories in 1968. His concept was based on e-beam-addressing to generate an electronic charge pattern corresponding to a video image, which in turn controlled the LC layer of a reflective LC cell. E-beam-addressing requires a CRT with a modified faceplate to generate a charge pattern on its surface. No practical application of this concept for projection purposes is known. However, a similar concept was used for print heads without an LCD.
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LCD projector AI simulator
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LCD projector
An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern equivalent of the slide projector or overhead projector. To display images, LCD (liquid-crystal display) projectors typically send light from a metal-halide lamp through a prism or series of dichroic filters that separates light to three polysilicon panels – one each for the red, green and blue components of the video signal. As polarized light passes through the panels (combination of polarizer, polysilicon LCD panel and analyzer), individual pixels can be opened (made transparent controlled by electricity) to allow light to pass or closed (made opaque controlled by electricity) to block the light. The combination of open and closed pixels can produce a wide range of colors and shades in the projected image.
Metal-halide lamps are used because they output an ideal color temperature and a broad spectrum of color. These lamps also have the ability to produce an extremely large amount of light within a small area; current projectors average about 2,000 to 15,000 American National Standards Institute (ANSI) lumens.
Other technologies, such as digital light processing (DLP) and liquid crystal on silicon (LCOS) are also becoming more popular in modestly priced video projection.
Because they use small lamps and the ability to project an image on any flat surface, LCD projectors tend to be smaller and more portable than some other types of projection systems. Even so, the best image quality is found using a blank white, grey, or black[citation needed] (which blocks reflected ambient light) surface, so dedicated projection screens are often used.
Perceived color in a projected image is a factor of both projection surface and projector quality. Since white is more of a neutral color, white surfaces are best suited for natural color tones; as such, white projection surfaces are more common in most business and school presentation environments.
However, darkest black in a projected image is dependent on how dark the screen is. Because of this, some presenters and presentation-space planners prefer gray screens, which create higher-perceived contrast. The trade-off is that darker backgrounds can throw off color tones. Color problems can sometimes be adjusted through the projector settings, but may not be as accurate as they would on a white background.
A projector's throw ratio is used when installing projectors to control the size of the projected display. For example, if the throw ratio is 2:1 and the projector is fourteen feet away from the screen, then the display width will be seven feet.
Early experiments with liquid crystals to generate a video image were done by John A. van Raalte at the RCA-Laboratories in 1968. His concept was based on e-beam-addressing to generate an electronic charge pattern corresponding to a video image, which in turn controlled the LC layer of a reflective LC cell. E-beam-addressing requires a CRT with a modified faceplate to generate a charge pattern on its surface. No practical application of this concept for projection purposes is known. However, a similar concept was used for print heads without an LCD.