Pros and Cons of LCD Projection Systems - dummies

Pros and Cons of LCD Projection Systems

By Danny Briere, Pat Hurley

If you’re in the market for an LCD projection system, consider the pros and cons. You can buy LCD front-projection systems that provide a high-quality (often HDTV) picture at a price that is typically lower than that of CRT front-projection systems. LCD technologies have been used for years for relatively low-quality projectors — the kind you might have in the conference room for projecting slides on a white board. But the LCD has come a long way in the era of home theater.

Benefits of LCD projection systems

LCD projector systems have several big advantages, when compared with other projectors:

  • Lower-cost front projectors: You can buy a quality 720p LCD front projector for less than $1000.

  • More compact RPTVs: Because the LCD panels and the lamp are small, LCD RPTVs can be much thinner than CRT RPTVs. Although many CRT systems can be 36 inches or more deep, LCD systems can be less than 15 inches deep.

  • Bright pictures: The separate lamp used in LCD projectors puts out a ton of light. The result is a brighter picture that can tolerate more ambient light in your home theater.

    For the best brightness and color reproduction, look for LCD projectors (typically only RPTVs) that use LED backlights instead of traditional bulbs.

  • No need for convergence: Despite the fact that an LCD projector contains three LCD panels, it has only one light source. So you don’t need to converge the picture like you had to do with the older CRT projector technology. This makes the setup much easier.

  • No worries about burn-in: Plug in that Xbox or PlayStation and play all the games you want. Because LCD systems don’t use phosphors, they can’t get permanent burn-in like CRTs (or flat-panel plasma systems) can.

Drawbacks of LCD projection systems

Of course, there’s got to be a downside, right? LCD projectors don’t do a few things well:

  • Relatively poor black performance: LCD projectors, like LCD direct-view sets, can’t display true black tints well. Dark scenes end up being gray instead.

  • Short lamp life: Nothing lasts forever, and the high-output lamps on LCD projectors tend to wear out after a few thousand hours of use. This life span is much less than the life span of a plasma TV, but LCD projector lamps cost a lot less to replace.

  • “Stuck pixels” problem: These are usually minor manufacturing defects that cause individual pixels to not light up when the display tells them to. Because the relative size of pixels in a projection system is large, you may notice a dead pixel on your screen. Many manufacturers think that having a few stuck pixels is just part of doing business, and they will not replace your LCD panels except in extreme cases. As a result, it is a good idea to find out the manufacturer’s dead pixel policy before you buy.

  • “Screen door”: When LCD images are projected onto big screens (like the ones you find in a front-projector system), you can begin to see the pixel structure of the LCD itself — the physical structure of the LCD that separates the individual pixels. Because of the way LCDs are constructed, you can look closely at a large projected image and see dots of lighter and darker areas — like you’re looking at the world through a metal screen door. This “screen door” effect is typically noticeable only if you’re too close to a big image though.

For more information on LCD projection displays, a listing of current models, check out 3LCD, a consortium of manufacturers of LCD projection systems.