Video Projector:
A video projector uses lens system to project the image on the projection screen after receiving a video signal. These video projectors project the image using very bright light and can even correct some inconsistencies like blurriness and curves. Some video projectors come built in a separate cabinet as in case for home theater projectors.
Common resolutions for video projectors are 800x600 pixels (SVGA), 1024x768 pixels (XGA) and 1280x720 pixels (720p).
Video projectors use LCD, CRT and DLP projection technologies for projection of images.
LCD technology:
The Projectors using LCD technology use LCD light gates. It is very common in home theater systems and business applications, because of its simplicity and affordability. The only problem with this system is its "screen door" also known as pixelation effect.
CRT technology:
Projectors using CRT technology use Cathode Ray Tubes for projection of images. There are usually three tubes namely, red, green, and blue in it. Unlike lamp using projectors it requires minimal maintenance. These projectors are very expensive, costing over $10,000.
DLP technology:
This technology for video projectors was developed by Texas Instruments. The technology uses either one, two or three Digital Micromirror Devices, which are microfabricated light valves. It uses colour wheels to modulate colours.
It is the most dominant technology being widely used for portable digital projectors. It is also the most expensive technology, because of its three colour wheels used for colour modulation.
Some of the best Video projector manufacturing brands are:
ASK Proxima
Canon
Epson
InFocus
Mitsubishi
NEC
Panasonic
Sony
Sanyo
Toshiba
These brands offer projectors with different resolutions at a price range of $600 to $3000. Some are very expensive like the Sanyo PLV-HD 150 Home theater projector that costs around $7400. The cost of a projector not only depends on its resolution but also on its brightness.