The first thing to understand about rear projection televisions is that they use
one of four technologies: CRT, LCD, DLP™ or LCoS. The various technologies that
can be used inside a rear projection television are covered in depth in the
Learn About The Technologies
section.
Regardless of which technology powers a rear projection television, they all
operate in much the same manner. All rear projection televisions start with a
projector at the base of the television cabinet. This projector is simply a lower
powered version of a front projector with a very short throw lens, meaning that
its lens can make a very large image without having to be very far away from the
screen.
The projector is situated so its projected image is bounced off of one-to-two
mirrors, depending on which technology is used. CRT-based rear projection usually
uses one mirror, while microdisplay technologies use two. The image is then
projected onto a special screen that allows it to be seen through the screen,
which is called a rear projection screen. Figure 1. shows a typical set up for
a microdisplay (DLP™, LCD, or LCoS) powered rear projection television, and a
CRT powered rear projection television.
Figure 1
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