Rear Projection TVs (RPTV)
This TV format isn’t mass market, nor does the colour tend to be as rich and sharp as other formats such as LCD. However, they could be for those looking for a large-screen ‘home cinema’ experience, with screens reaching 100" or more. Surprisingly perhaps, given their size, RPTV sets can be relatively low in energy consumption.
Energy figures given are per square inch of screen area
How It Works
As the name suggests, the image in a rear-projection television set is created by a projection from the rear of the unit. There are four types of RPTV currently available: CRT - Cathode Ray Tube; DLP – Digital Light Processing; LCD – Liquid Crystal Display; LCoS - Liquid Crystal on Silicon. The bulky CRT set is becoming less popular, in favour of the newer types - termed ‘microdisplay’, as they use pixel-containing microchips.
The CRT set works like an ordinary cathode ray tube television, but on a much larger scale, with three tubes creating the screen image. With the DLP set, a screen image is created by projectors and thousands of tiny mirrors, as light beams pass through a rotating colour wheel. LCD projection technology is similar to a slide show, as light is passed through a silicon chip and then magnified to create a larger screen image. The LCoS uses liquid crystal instead of mirrors to create a picture image.
In all RPTVs picture quality is regarded as excellent – with the capacity to display HDTV at full resolution.