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March 2006

This chapter is from the book

WEDNESDAY: MARCH 8, 2006

THIS WEEK’S FOCUS: Choosing a Big-Screen TV

DLP REAR PROJECTION

When a CRT rear projector won’t work, consider a set based on the newer digital light projection (DLP) technology. DLP projectors are remarkably small and lightweight, thanks to the compact size of the necessary optical and electronic components. The largest manufacturer of DLP RPTVs today is Samsung.

The DLP system starts with the light generated by a high-performance projector lamp. The light from the lamp is projected through a condensing lens and shone through a rotating color wheel, which is composed of red, green, and blue segments. The color wheel spins rapidly to sequentially generate 16.7 million different colors from that single point of light.

The colored light now shines onto the digital micromirror device (DMD), which is an array of hundreds of thousands of tiny, independently hinged mirrors. There is one micromirror for each pixel in the display, all controlled by the DMD’s computer processor. The mirrors tilt on or off to reflect light through a projection lens and onto the display’s screen. A typical single-chip DMD generates a picture composed of 1280 x 720 pixels, although some newer models deliver 1920 x 1080 resolution, for a true 1080p high-definition picture.

DLP projectors have the brightest pictures of all RPTVs, with excellent black levels and shadow details. On the downside, because it’s a partly mechanical system, because of that color wheel, there are moving parts that can break. In addition, some viewers can see "rainbows" caused by the rapidly shifting colors; if you’re susceptible to this visual effect, consider choosing another display technology instead.

ON THIS DAY: VON ZEPPELIN DIES (1917)

On this date in 1917, Ferdinand Count von Zeppelin passed away; he was 79 years old. von Zeppelin was a German engineer, known primarily as a builder of rigid dirigible airships that became known as zeppelins.

HARDWARE OF THE WEEK: ATI HDTV WONDER

Add high-definition television to your PC with the ATI HDTV Wonder video card. This is a low-priced, high-performance video card that not only handles HDTV video, but also records via DVR functionality. Buy it for $149 at http://www.ati.com.

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