How LCD Projection Systems Work

If you're considering an LCD projection system for your home theater, make an informed decision by knowing a bit of how LCD projection systems work.

LCD projectors typically use three small LCD panels (a couple of inches across at most) — one each for red, green, and blue picture information. Behind these panels is a strong lamp that provides the light. Like plasma and LCD flat panels, LCDs are fixed-pixel displays, meaning that they display video at a certain resolution. You can find high-definition LCD-projection TVs with both 720p and 1080p resolutions. An internal device called an image scaler converts the incoming signal (such as 480p from progressive-scan DVDs or 1080i from an HDTV broadcast) to the 1366 x 768 resolution for display. LCD projectors are inherently progressive, so even standard-definition broadcasts are converted to a progressive-scan mode for display.

Some of the cheapest projectors are not high definition, with resolutions below 720p. These are fine for certain uses, but with high-quality 720p projectors from major manufacturers dropping in price, you should consider choosing HD when you buy an LCD projector. And in the case of front-projection systems where you’re going to be looking at a 100-inch or bigger screen, you should go for a Full HD 1080p projector if you possibly can.

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