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How Projection Television Works

Buying a Rear-projection TV

Front- and rear-projection TVs have some substantial differences. However, you'll still need to keep most of the same things in mind if you're shopping for either one. If you're in the market for a rear-projection set, here's what you should watch for:

  • Aspect ratio, screen size, resolution and frame rate: Most projection TVs have a 16:9 aspect ratio, and most, but not all, can display high-definition broadcasts. Make sure you get an HDTV or HDTV-ready set if you plan to watch programs in high definition. Also, unlike with a projector, the size of your set is fixed, so make sure to measure your room and figure out what size screen you want before you shop. Photo courtesy Panasonic and Matsushita Electric Corporation of America Rear-projection TVs take up more space than front-projection models, but they're more economical.
  • Color, black level and contrast ratio: DLP sets have a very good black level, and LCoS sets can as well, depending on the model.
  • Visual artifacts and burn-in: Rear-projection TVs have the same visual artifacts as front-projection TVs. Viewers experience the rainbow effect with some DLP sets, and LCD sets sometime have a visible screen door effect. CRT rear-projection sets are also prone to burn-in. In addition, the picture quality of a CRT set can degrade if the individual tubes move out of alignment. You'll need to calibrate the tubes in your set periodically to get the best picture quality. Most new sets will do this automatically.
  • Viewing angle and glare: CRT sets in particular tend to have a poor viewing angle. In addition, some projection TV screens have a noticeable amount of glare. You should check out both of these in person as you're shopping rather than relying on manufacturers' claims.
  • Connections: Rear-projection TVs have the same connection needs as projectors do. Make sure you'll be able to use your existing equipment with your TV. If you plan to upgrade to Blu-ray or HD-DVD, make sure your set has an HDMI connection for digital input.

Check out the links on the next page to learn more about projection TVs and different TV technologies.