What Is a Projection TV?
By Chris Moore
A projection TV is a television set that uses a video projector to display its picture. With the projector, the TV is able to cast a much larger image than most standard models, making the TV set into a small-scale cinema screen, which many owners use in their home theaters. A projection TV can be either rear projection, making it function like a standard TV set, or front projection, which works like a movie projector.
For years, televisions used cathode ray tubes--a vacuum tube where electrons are shot onto a phosphorous glass screen, creating a picture by illuminating the phosphors. Projection TVs use similar technology, but once the picture is created it is then projected through lenses to show a much larger picture. This allows projection TVs to have picture screens much larger that CRT TV's, since the screens would require an enormous piece of glass.
A front projection TV is essentially a video projector, one that can be connected to an antenna or cable/satellite TV receiver box. Functioning like any other projector, it sends the video through lenses to magnify the image and project it outward. An external screen is needed with a front projector to cast the picture onto. External speakers are also needed to connect to the TV source's audio output, since the projector doesn't have built-in speakers.
A rear projection TV uses a projector within the confines of a regular television frame, projecting the image onto the back of the screen. To accomplish this, the picture is first magnified with the lenses inside the TV and then reflected off mirrors. This causes the picture to be shown in reverse on the back of the screen and thus normal on the front of the screen. Plasma and DLP TVs are all rear projectors, and some even use a style of CRTs.
The type of projection TV you buy depends entirely on your preference. If you don't want to take up a lot of space, opt for a front projector. You'll need speakers, a place to mount the projector and a free wall to display the picture on. For best resolution and picture quality, pick a rear projector.
Projection TVs can be an even better option than other HDTV sets. Because they produce the original picture in a method similar to the old CRT TVs, their color contrast is better than that of LCD (liquid crystal display) screens while still producing an overall picture of 60 inches or greater. Despite this, projection TVs (especially rear projectors) are becoming harder to come by as LCD screens become more affordable.
Chris Moore has been contributing to eHow since 2007 and is a member of the DFW Writers' Workshop. He received a Bachelor of Arts in journalism from the University of Texas-Arlington.