Become a student of 'Projection Television 101' and get schooled in the technology of projection television systems.
Projection televisions have been around for quite some time now. When
first introduced, the images created by these sets were fuzzy and only
viewable at a distance. As great strides in TV technology have been
made, projection TV images have become sharper and more comparable to
those of their competitors.
For people in the market for a large screen TV, either for a home
theatre system or a classroom/boardroom presentation setting, a
Projection TV is the most efficient choice. CRT or cathode ray tube
set's size maxes out around 40", and at that size they are extremely
heavy and bulky. Plasma displays are manageable with larger screen
sizes but can be very expensive. Projection TV technology can create
very large screen TVs which are not only manageable but affordable.
Projection televisions have four main components: a projector, screen,
control panel, and a sound system. There are two main types of
projectors used for these TVs: a transmissive projector, where light
shines through the image forming element (CRT tube, LCD panel), and a
reflective projector in which light is bounced off of the image forming
element. In both projectors, a lens gets the image from the image
forming element, magnifies the image and focuses it onto a screen. Top
of the line projection TVs use primarily reflective projectors because
the advances in reflective projector technology of late have been more
progressive than those pertaining to transmissive projector technology.
The image forming elements used in transmissive projectors are CRTs and
LCDs. TVs using a CRT for projection actually have a small (around 9"
diagonal) television built in. A lens in front of this small, extremely
bright CRT TV magnifies the image and projects it onto the screen.
Three basic configurations are used in these sets. Transmissive
projectors using an LCD for projection are substantially lighter with a
higher resolution capacity than their CRT counterparts. The LCD panel
used in projection TVs is very similar to that of a full sized LCD only
smaller and brighter. This panel is backlit by a halogen lamp, the
image on the panel is transmitted through a magnifying lens and
projected onto a screen.
Reflective projectors use a small reflective chip to form the image.
When light shines on this chip, it is reflected off of it, through a
projection lens and onto the screen. The most exciting developments in
projection TV technology have been made with reflective projectors
using micro-electromechanical systems and liquid crystal on silicon.
With advances in LCD and MEM technologies, projectors will become
smaller and form closer competition between projection TVs and the new
plasma displays, in areas such as resolution and crispness of image
detail. A relatively new application of projection TV technology is,
"virtual reality", in which the viewer feels surrounded by, or as
though he/she is a part of, the image being viewed. Projection TVs may
not be the next big thing to hit the shelves, but we can be sure they
will continue to be a viable, low priced option when shopping for your
new TV.
