There are four types of rear-projection TV's available currently. These are the older CRT rear-projection, DLP rear-projection, LCD rear-projection and LCoS rear-projection. Most available today are HD ready and can display digital signals.
CRT Rear-projection : these are the projection TV's that have been on the market for years. CRT or Cathode Ray Tube technology is the same technology that your old TV set's used. There are three tubes in these projection TV's each for a primary color and they project the light onto the TV's screen. Since they require three CRT tubes these TV's are very big and deep. Most CRT projection TV's come in 50 inches or larger screen size. CRT rear-projection TV's are becoming extint and many companies do not make them anymore. They need to be adjusted frequently to keep the colors in line and the image quality and viewing angles are not as good as the next three rear-projection technologies.
DLP rear-projection : (Digital Light Processing) are based off of technology developed by Texas Instruments. They produce an image by sending light through a spinning wheel of color which then sends the light to almost a million small mirrors. These mirrors produce the image onto the screen. DLP rear-projection TV's have slimmer cabinets than CRT rear-projection TV's. The biggest complaint with DLP rear-projections are the "rainbow effect" many people see. Also the bulb that produces the light for the TV needs to be replaced usually every 8,000 viewing hours.
LCD rear-projection : LCD rear-projection's use a LCD screen which is projected unto the screen. These TV's like DLP rear-projection are slimmer than the CRT rear-projection TV's. Image quality on LCD rear-projection is not as good as DLP and viewing angles are not that large. Viewing an LCD rear-projection from the center position is recommended. Also many buyers complain that moving images are pixelated and I have seen this first hand.
LCoS rear-projection: is the newest technology of the four types of rear-projection TV's. Liquid Crystal on Silicon rear-projection TV's is basically a hybrid between an LCD rear-projection and a DLP rear-projection. In these TV's light shines through LCD panels and is then modulated through these panels by the liquid crystals. The liquid crystals do the job that the mirrors do in DLP rear-projection TV's. LCoS are touted as not having the "rainbow effect" and can be made thinner than the other rear-projection TV's. A downside to these TV's is the technology is still very expensive so many companies do not make them.
