These devices can be attached to a
computer or video device just as you would connect a traditional
The term "big screen" is
used to indicate a TV size larger than 40 inches in diagonal
measurement. Until recently these are usually rear-projection screens,
although we are seeing more and more flat-panel displays at competitive
The appeal of Rear-Projection TV (RPTV)
There certainly is a great deal of
consumer appeal for RPTVs these days. And it's easy to understand. Part
of it is due to the simplicity of the product. After all, what could be
easier than getting a bigger TV? If you want a larger image with no muss
and fuss, it can be purchased from any local big-screen retailer and
delivered within a day or two.
Another the appeal of RPTVs is the
impression created by big-screen retailers that RPTVs are cheaper than
front projection systems.
Clearly there is a market for both
types of home theatre solutions. From a practical perspective your room
size has a lot to do with determining which approach is best for you. If
you don't have a large viewing room, a 40" to 60" diagonal TV will
probably be plenty. In this case, the rear-projection solution is more
practical assuming you can fit the box into the space.
But if you want the large screen cinema
experience and your room size will allow it, front projection is the way
to go. Front projectors are made to produce screen images in the range
of 70" to 120" diagonal or more. Once people realize they can get a
picture up to four times the size for the same money as a good RPTV, it
opens up a whole new world of entertainment possibilities.
How good is the Rear-Projection TV:
As noted above, the advantages of RPTVs
are obvious. There is a wide array of products in different sizes and
price ranges. There are usually several local showrooms in most areas.
And they are simple to buy and install. However, RPTVs have several
limitations that front-projection systems do not. Among them are limited
screen size, poor viewing angles, excessive reflections, poor aspect
ratio management, and loss of floor space.
Screen size is an obvious difference,
but still worth thinking about for a moment. A 100" diagonal front
projection screen is four times the surface area of a 50" RPTV. If you
want to put real "theatre" in your home theater, the projector and movie
screen approach delivers it. RPTVs are just big televisions.
A digital projector is an
electro-optical machine which converts image data from a computer or
video source to an image which is then displayed on a distant wall or
screen using a lens system. A typical resolution for a portable
projector will be the SVGA standard (800×600 pixels), with more
expensive devices supporting XGA (1024×768 pixels). The cost of a device
is not only determined by its resolution, but also by its brightness.
For use in large conference rooms the brightness should be between 1,000
and 4,000 ANSI lumens.
There are four competing digital
projection technologies: high intensity CRT, LCD projectors using LCD
light gates, Texas Instruments' DLP technology and LCOS or liquid
crystal on silicon. In 2004 and 2005, LCD front projection has been
enjoying a come-back because of the addition of the dynamic iris which
has improved contrast up to the levels of DLP.
There is a genuine market for both
RPTVs and projectors for home theatre. RPTVs are simple, but they have
limitations in screen size and performance. Projectors and screens
require some installation work, but once it is done you end up with a
more dramatic theatre experience.
The bottom line is this: if you are
looking at digital RPTVs and your viewing room can accommodate a 90" or
100" screen, don't overlook the possibility of a projector and screen
instead. If you can afford a digital RPTV, you can afford a projector.
And dollar for dollar the projector will often deliver the maximum "wow"
factor for the money invested.