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May 2012

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by Jeff Sauer

A lot of large-screen display types offer excellent images and some in enticingly slim wall-mountable form factors. But still nothing beats front projection when it comes to presenting visuals that are large enough for a congregation of hundreds or thousands of worshippers to see. And ultimately, there’s nothing thinner than light on a screen.

Of course, front projection installation can seem more complex than the apparent simplicity of plug-and-play monitors, due to projection distances and positioning, ambient light concerns, screen types, and more. But understanding the basics of projection can go a long way toward helping you choose a projector that will fit the space in your house of worship.

There are three major imaging technologies in today’s projectors—3LCD, DLP, and LCoS—and all are now quite mature and able to generate high quality images. Most medium-large venue projector manufacturers, including Barco, Boxlight, Christie Digital, Digital Projection, Eiki, Hitachi, Mitsubishi, NEC, Panasonic, ProjectionDesign, Sanyo, and Toshiba, have product lines that include both LCD and DLP projectors. In the past, Sony has used all three technologies, but currently offers only LCD and LCoS (SXRD) models.

3LCD
3LCD, the oldest of the three technologies, uses three aligned LCD panels to create images. Think of these panels as miniature versions of your laptop computer screen that range in size from a little more than 0.5-1.5 inches in diagonal, each with a grid of thousands of pixels (a native 1024x768 XGA panel has an array of 1,024 columns and 768 rows of pixels).

A projection lamp shines through the LCD panels to create light on the screen, with liquid crystals—the “LC” in “Liquid Crystal Display”—inside each pixels that twist when changed with electricity to allow none, some, or all the light to pass through, thus creating black, gray, and white images. Color comes from filtering red, green, and blue light from the white backlight and into three light paths, one going to each of the three panels. Blending the resulting light from the three panels yields 3LCD’s reputation for rich, accurate color.

Epson, the leading manufacturer of the panels, and Sanyo, a leading maker of LCD-based light engines, are almost exclusively LCD. For more information about 3LCD technology, visit www.3LCD.com.

DLP
Texas Instruments’ DLP, or “digital light processing,” is some 20 years old and has been in projectors for well more than a decade. It, too, uses an amazingly small array of pixels, but one that’s even more mind-boggling. Imagine roughly a million tiny mirrors on a chip of 0.5-1.5-inches diagonally that independently pivot toward and away from the projection lamp tens of thousands of times each second to produce black, gray, and white light on the screen. These micromirrors and their inherent brightness advantage over LCD panels helped DLP overtake LCD in projector sales during the years when light output and projector miniaturization were at such a premium.

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Jeff Sauer has covered the professional video and A/V industry for a dozen years and is an independent video producer and consultant in Massachusetts.