Overview

LCD (Liquid Crystal Display) TVs use red, green, and blue liquid crystals to control the color of a specific pixel. Each red, green, and blue liquid crystal makes up a single pixel. A matrix of liquid crystal pixels is then used to make up an image. Unlike plasma technology, which has phosphors that produce light when electrically excited, LCD technology requires some form of backlighting to pass through the red, green, and blue liquid crystals. Controlled electrical voltages manipulate the liquid crystals into letting a certain amount of light pass through. After light exits the LCD panels, the three colored beams are combined by a prism and projected onto the screen by a lens.

There are two types of LCDs: rear projection and flat panel. The difference between the two is how they project the back lightning required for LCDs. As its name implies, rear projection uses rear projection lamps to provide the light going through the liquid crystals. Rear projection lamps allow LCDs to get 50 inches and larger screens. Flat panel LCDs are very thin because they use slimmer back lighting techniques to reflect light through the liquid crystals. The disadvantage of flat panel LCDs is their size limitations which is usually less than 50 inches. See the image below for an illustration on the inner components of a LCD HDTV.

Production Update

Upside

• Available in small sizes
• Thin and wall mountable
• Great picture quality
• Great colors
• High brightness levels – viewable in a bright room
• No burn-in. Important if you watch a lot of 4:3 images or use a HTPC

Downside

• Screen Door Effect (SDE) - makes for a grainy image. This is due to the fill factor and the space needed between each LCD pixel for electrical wiring. Older models show SDE as far away as 10’ from the screen. Newer LCD TVs have minimal SDE.
• Not the best blacks which leads to lack of shadow depth.
• Motion Blur - due to the refresh cycles LCD technology requires. Newer LCD models with 5ms or less response time have reduced motion bur.
• Limited viewing angles.
• Flat panel LCDs are limited in size, typically 50” and smaller. However, rear projection units don’t have this problem.

Find more LCD HDTVs at BuyLCDHDTV.com

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