Rear Projection TV's

When talking rear projection TV's, there are actually three different types CRT, DLP and LCD, though there are a few variations of LCD rear projection TV's. Rear projection TV's are big screen TV's that are less expensive than the equivalent size Plasma or LCD TV and for that reason are still a popular choice with consumers. Since the release of the DLP rear projection technology it has become a favourite amongst home theatre owners.

CRT Rear Projection pros and cons
DLP Rear Projection pros and cons
LCD Rear Projection pros and cons

A rear projection TV is basically a TV that projects a video image from a smaller source onto a larger surface from behind the screen using a system of mirrors. This is different from a video projector (which projects the video image from the front of the screen).

CRT Rear Projection - has three cathode ray tubes in the TV set, one for each of the primary video colours, red, green and blue.
DLP Rear Projection - Digital Light Processing (DLP) rear projection uses a DMD (Digital Micromirror Device) chip with thousands of tiny mirrors to reflect coloured light. Each mirror on the chip represents one pixel in the final image. Projecting this image through a lens produces the picture on the screen.
LCD Rear Projection - passes a light through a Liquid Crystal Display (LCD) chip which contains video pixels that are magnified through a lens and then projected onto the screen. A LCoS (Liquid Crystal on Silicon) rear projection TV is a variant of LCD Rear Projection technology.

CRT rear projection pros and cons

As CRT's are less expensive to manufacture as the technology has been widely used for a number of years, CRT rear projection TV's are less expensive than LCD, DLP, and LCoS rear projection TV's.
CRT technology is able to produce the blackest of blacks, a full range of colours and better brightness that the other rear projection technologies. This means that the images displayed on a CRT rear projection screen are the clearest and more film-like.
CRT rear projection TV's are susceptible to burn in. This occurs when an image is in the same place on the screen for a long period of time, e.g. a TV channel logo, and when the picture changes a ghost image can still be seen.
As CRT rear projection TV's need up to 3 CRT's (one each for red, blue, and green colours), they are generally quite deep. They are not only deeper than LCD and Plasma TV's but also deeper than equivalent DLP, LCD and LCoS rear projection TV's.
By having 3 CRT's in the TV, these have to be aligned so the colours mix correctly. If these tubes are not aligned, colour haloing can occur. Also, if one of these tubes fail, all three need to be replaced.

DLP rear projection pros and cons

DLP rear projection TV's don't suffer from the screen door effects like LCD and LCoS rear projection TV's can. The picture appears to be seamless and you will find it difficult to see when one pixel ends and another begins.
The chip in a DLP rear projection TV is a lot smaller than the 3 CRT tubes that are required in a CRT rear projection TV, which means that a DLP rear projection is a lot thinner and lighter than its CRT counterpart.
Because of its reflective technology, DLP rear projection TV's have high contrast and brightness levels (though generally not as high as LCD's) which means the picture can still be seen in brightly lit rooms.
DLP rear projection TV's are good for gaming and fast moving images due to their high refresh rate.
DLP technology consumes less power than other rear projection methods.
Due to their clear and non-pixelated images, DLP rear projection TV's can also be used as a computer monitor capable of viewing web content and graphic-intensive images.
The bulbs that produce the light source for the TV last between 8000 and 10,000 hours (around 4.5 years if watched for 6 hours per day). If they do wear out can easily be replaced.
DLP rear projection TV's aren't affected by the screen door effect but potentially a viewer can see a brief flash of colour (like a small rainbow) when looking from side to side rapidly. This is known as the rainbow effect.
DLP rear projection TV's are more expensive than their CRT rear projection counterparts as the technology to manufacture the DLP chip is more complex.

LCD rear projection pros and cons

LCD chips are a lot smaller than the 3 CRT tubes that are required in a CRT rear projection TV, which means that a LCD rear projection is a lot thinner and lighter than its CRT counterpart.
LCD technology has a low power consumption.
LCD technology allows high brightness and contrast capabilities in comparison to the other rear projection TV types.
As a LCD rear projection screens are vulnerable to the screen door effect.
There is a potential for a pixel in the LCD rear projection screen to burn out which displays a black or white dot on the screen. Individual pixels cannot be replaced so to fix a burnt out pixels means replacing the LCD projection unit or the entire display.
LCD rear projection TV's are more expensive than their CRT rear projection counterparts as the technology to manufacture the LCD chip is more complex.

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