Rear Projection Vs Flat Screen Technology
Unlike a flat screen television, which produces a picture by digitally sending the signal to the screen itself, a projection television actually projects the image from behind the screen. Because of this, projection TVs are bigger than their flat screen counterparts, which has made them increasingly unpopular in today's market. However, it is untrue that flat screen TVs provide a better picture, or that they are the only kind capable of high definition. Some would even argue that rear projection provides the kind of quality imaging that cannot be found in flat screen varieties. There are three main kinds of projection TVs and they each work in their own unique way.
As it sounds, a projection television, or more commonly a "rear-projection" TV, works by projecting an image from behind the screen itself. Currently, there are three main types of technology used in rear-projection TV's: CRT, LCD, and DLP. Each uses a combination of projection devices, magnification lenses, mirrors, and screens to produce the image seen. However, each takes an alternate approach and each has its own sets of advantages and disadvantages.
The Cathode Ray Tube (CRT)
CRT technology represents the basic fundamentals of projection television stretching back to the early days of TV. These are the workhorses of the TV industry, and there are those who insist that they still provide the clearest picture of any high definition technology. The projector works by using three cathode ray tubes: red, green, and blue. With these three primary colors, the entire spectrum of colors can be produced. The benefits to CRT technology include the higher picture quality and the fact that--arguably--the TVs can produce the broadest range of colors. The technology itself, being the oldest and most well tested, is also less expensive than its competition. The disadvantages include the very real possibility of screen burn in (where an image--kept too long on the screen--can indelibly leave a ghost of that image on the screen permanently) and the size of the television required to house the large projector.
Liquid Crystal Display (LCD)
LCD projection televisions work by using a strong light to shine into a liquid crystal chip. This chip contains the pixels that are then passed through a magnifying lens and then projected onto the television screen. These TVs provide a crisp image that is usually brighter than either DLP or CRT displays. However, with that added brightness comes a loss of contrast, sometimes important to those who treasure an authentic cinematic experience. There is also the possibility of pixel burnout, meaning a single pixel or two can cease to work, thus causing a distraction on the image.
Digital Light Processing (DLP)
DLP televisions are the final technology used in rear projection. The process is not dissimilar to LCD displays. The image is generated through a chip, which uses tiny mirrors to turn a digital signal into a full high definition presentation. In contrast with LCD technology, the brightness of the display is often the primary drawback of DLP televisions. However, the contrast is superior. DLP is also the most durable of the RP televisions, rarely suffering from burn-in, and without the possibility of pixel burnout.
Tags: flat screen, high definition, projection television, behind screen, from behind