Sunday, April 15, 2007

Projection TV Shopping Guide

by xpGadgets

More information in our Television shopping guide

* Pros and Cons of Projection TV
* How Projection TV works
* Things to consider when buying a Projection TV

Pros and Cons of Projection TV

Projection TVs (including front projectors) may not have the striking stylish appearance, but they are still among the best of TVs because:

1) They offer big screen size with reasonable price. Till now, projection TVs still offers the biggest screeen and the best screen size to cost ratio.

2) Relatively thin and light comparing tradional CRT sets.

3) Achieves deeper, more realistic shadows and blacks than direct-view Plasma and LCD TVs

4) No burn-in effect, relatively long life.

But it also have some shortcomings (newer models have made some improvements)

1) Not-so-bright colors, uneven brightness throughout the screen (darker corners, brighter center)

2) Takes a lot of space comparing with Plamsa TVs or LCD TVs.

How Projection TV works

In contrast to conventional TVs, projection TVs form a small image on a device inside the projector -- either a CRT, LCD or LCoS -- and then shine that image onto a large screen located elsewhere.

In Rear (reflective) Projection TVs (RPTV), the screen is located within the TV box itself and light reflects off the projection display panel and is then projected onto the screen. While in Front (transmissive) Projection TVs (Front Projectors), the screen is located across the room, light passes through the image-forming display panel and is then projected onto a screen. Most Projection TVs we saw are rear projection TVs.

Projection TVs can be divided into 3 categories according to the techology they use to form the image

DLP Projection TVs: DLP TVs use a small chip called DMD (Digital Micromirror Device) to reflect light from a lamp onto screen. Cheaper models use a color wheel to produce color, while more advanced models dedicate one chip each to the red, green and blue.

* Pros: The cheapest projection TV. It also offers the best blacks and shadows among all projection TVs (actually only next to traditional CRT TVs among all TVs)
* Cons: usually more prone to the rainbow effect.

LCD Projection TVs: It uses the same technology as direct-view LCD TVs and monitors. A matrix of TFTs (Thin-Film Transistors) supplies various voltage to liquid crystal-filled cells sandwiched between two sheets of glass to filter light passing though them.

* Pros: Brighter image and more accurate colors than DLP TVs
* Cons: The worst blacks and shadows among all TVs, prone to pixelation and screen-door effects ( i.e. dark grid on screen. Select 1024x768+ resolution for LCD front projectors to reduce the effects)

LCoS Projection TVs: A pretty new one. LCoS also use liquid crystals (applied to a silicon chip instead of sandwiched in 2 glass panels) to filter light, then the light is reflected off the chip to the screen. Like DLP TVs, it can either use a color wheel to produce color or use 3 chips for the primary colors.

* Pros: Offers the highest resolution among all projection TVs, hence produces smoother, more detailed image.
* Cons: Only a few models using this techology are available, very expensive.

Things to consider when buying a Projection TV

RPTVs or Front Projectors: Usually RPTV offers better image quality and has less limitation on rooms while front projectors are more flexible and cheaper.

Hot Projection TV deals and Projection TV shopping guide brought to you by xpGadgets.

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