Technology Showcase: Large HD Projectors
May 1, 2008 12:00 PM, By Jay Ankeney
New technologies expand market.
Specs referred to as “ANSI lumens” are actually the average of measurements taken from nine areas across a screen's surface in a 3×3 matrix. Sometimes a more accurate figure is called “center lumens,” which is the brightness of maximum white in the center of the screen as measured with a spot photometer. Center lumens is typically a higher value because it is a record of the brightest portion of the screen. The best lumens information available from each manufacturer will be included in this article.
At the beginning of this year, 3LCD announced its support for the new color brightness metric that is being submitted to the International Organization for Standardization (ISO) for light output measurement. Color brightness specifies a projector's ability to deliver the levels of the red, green, and blue of a projector's output — not just its whiteness — and should empower more accurate comparisons of different projection systems than straight lumen measurements.
Texas Instruments is the manufacturer of Digital Light Processing (DLP) chips, which use arrays of tiny reflective surfaces to direct light onto a screen. These optical semiconductors are called Digital Micromirror Devices, with the amount of mirrored surfaces in each array determining the output's potential native resolution. Three-panel DLP technology is used in projectors from around 8000 lumens soaring up to 30,000 lumens and higher.
For many years, those reflective surfaces have been 0.95in. diagonal measurement with resolutions ranging up to WXGA (Wide XGA) for 1366×768 pixels with an aspect ratio of 16:9, and WUXGA (Widescreen Ultra XGA) for 1920×1200 pixels at 16:10 screen aspect ratio. Texas Instruments has recently brought out an array with 0.7in. reflective surfaces, which could potentially cut the cost of high-definition DLP projectors in half, depending on how much investment the manufacturer puts into the rest of its projection system.
In 2005, Texas Instruments brought out its BrilliantColor technology to enhance color processing by adding yellow, cyan, and magenta colors to the rendering of the image so a DLP projector can maintain bright white points while providing deeper red, green, and blue colorimetry. BrilliantColor also improves the optical efficiency of DLP display engines, letting them achieve up to 50-percent improvement in brightness over traditional three-color solutions.
There is also the LCoS approach to lightengines, which is a reflective technology similar to DLP projectors, but using liquid crystals instead of individual mirrors. Several companies produce their own proprietary version of LCoS, such as Sony with its Silicon X-tal Reflective Display (SXRD) approach and the JVC Digital Direct Drive Image Light Amplifier (D-ILA) concept.
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