Glossary
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brightness (lumens)
The visual perception of light output. A standard called ANSI lumens is used to compare projectors. The larger the number of lumens, the brighter the projected image should appear. To put things in perspective, consider that a wax candle generates 13 lumens, while a 100-watt light bulb generates 1,200.
The industry average for a projector used in a conference room ranges from 1,000 to 2,500 lumens.
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colors
Refers to the number of colors that can be displayed at one time based on the number of bits used to hold a pixel. More is better: 16 bits equals 65,000 colors, whereas 24 bits equals 16.7 million "true colors." Digital video requires at least 16 bits, and 24 bits produce realistic TV-like colors.
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contrast ratio
The difference between the lightest and darkest portions of an image. The larger the contrast ratio, the greater the ability of a projector to show subtle color details and tolerate a room's ambient light.
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dimensions
The actual size, or "footprint," of a projector.
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home theater screen
The home theater screen is the surface onto which an image is projected. A high-quality screen contributes to a crisp, clear image.
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keystone correction
A projector's ability to correct the effects of "pointing up" or "pointing down" at a screen, enabling the projector user's audience to view a rectangular image rather than one with a wider top or bottom.
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projection lamp
The type of lamp in a projector, including its wattage and estimated lifetime.
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projection lens
The type of lens in a projector. Its effectiveness is indicated by a throw ratio. The throw ratio represents the projector's distance from the screen compared to the width of the projected image.
Projectors come with either a fixed focal length or a zoom lens. With a fixed focal length lens, the projector must be moved to adjust the image size on screen. Zoom lenses allow adjustment to the image size without moving the projector.
Lenses for large screen projectors are often sold separately. Large-venue display installers often rely on third parties to provide lenses suitable for long- and short-throw applications.
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resolution
The degree of sharpness of a displayed image. On screen, resolution is expressed as a matrix of pixels. For example, a SVGA resolution of 800 x 600 translates to 800 pixels horizontally and 600 pixels vertically, or 480,000 pixels total. The larger the pixel count, the greater a projector's resolution.
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screen gain
Screen gain describes the extent to which a projection screen can make a projected image appear brighter. For example, a screen gain of 1.3 will make a projected image look 30 percent brighter than it would if the same image were projected on a screen with a gain of 1.0, or neutral.
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system
The configuration of a DLP® projection system, which consists of either one or three DLP® chips. The DLP® chip is an optical semiconductor containing an array of microscopic mirrors.
Generally, one DLP® chip is used in front projectors, TVs and video walls, while three DLP® chips are used for large-screen projectors and DLP Cinema® applications.
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weight
The lightweight nature of the DLP® projection system enables manufacturers to create lighter business projectors for optimal portability.
Whether you're looking for an 800- or 2,500-lumen output, you can find it in a projector weighing 6.6 pounds or less. These are classified as microportables, and can reach an output of up to 2,000 lumens while weighing as little as 2 pounds.
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