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LCD vs. DLP vs. LCoS

You may have come across the mammoth three-gun CRT projectors of yesteryear, but the latest crop of digitized beamers are now powered by three display technologies: LCD, DLP and LCoS. Each of these has been implemented in home theater and multimedia applications, differentiated by their unique strengths and weaknesses as follows:

Liquid Crystal Display (LCD)

The most mature technology among the trio, LCD projectors have an underlying optical engine that comprises three independent liquid crystal display panels for the primary red, green and blue colors. Each of these transmissive panels contains thousands of pixels used to modulate light from a lamp, which is then combined by a prism to form a full-color image onscreen. Currently, almost all offerings under this genre are using Epson's 3LCD engine.

Pros	Cons
Short to mid throw	Screen door effect
Vertical and horizontal lens shift	Dead pixel and dust blob
High brightness	Panel convergence problem
Sharper image	Grayish black
Excellent color saturation	Somewhat bulky
Most affordable

Due to the LCD panels' wider pixel structure, there's a tendency that the projections can be a bit more pixelated or even exhibit a "chicken wire" grille-like effect. They're also prone to dead/fixed pixels plus dust blobs that are trapped on the panel overtime. Nonetheless, these issues have been greatly minimized with the new-gen engines, though color haloing can still be a potential problem due to the panels' misalignment.

Digital Light Processing (DLP)

An innovation from Texas Instruments, DLP uses a chip embedded with millions of microscopic mirrors which represent each individual pixel. This is used to reflect light in conjunction with a spinning color wheel comprising filters in different shades, including primary colors to render an image. Premium models, on the other hand, have three of such DLP chips similar to the LCD, capable of delivering even richer hues without the bottleneck of a color wheel.

Pros	Cons
Deeper blacks	Mid to long throw
Smoother images	Rainbow anomaly
High brightness	Most models lack lens shift
Higher contrast than most LCDs	Three-chipper extremely pricey
Compact one-chipper
Relatively inexpensive

One major concern for single-chip DLPs is the infamous rainbow anomaly or streaks of random colors. This is most apparent in slower 2x to 3x speed color wheels, as well as during fast-moving scenes, etc. Furthermore, most entry to midrange DLPs lack both lens shift and powerful optical zooms, making them less flexible to set up and requiring longer throw distances to cast similarly sized projections.

Liquid Crystal on Silicone (LCoS)

A hybrid implementation of LCD and DLP technologies, LCoS has liquid crystals in place of the DLP's mirrors. But like LCDs, a LCoS projector's optical engine typically employs three chips for the primary colors. Despite its late entry and modest market share, there're already two major derivatives available now, namely JVC's Direct Drive Image Light Amplifier (D-ILA) and Sony's Silicon X-tal Reflective Display (SXRD).

Pros	Cons
Short to mid throw	Low brightness for home theater models
Vertical and horizontal lens shift	Somewhat bulky
Higher resolution	Limited selection
Smoother images	Pricey
Excellent color saturation
High native contrast for home theater models

There're definitely more pros than cons, though the LCoS beamers' high starting price make them less attractive than the inexpensive LCDs and DLPs. Added to that, choices are limited with entry sets surfacing only in the recent years. A proper darkroom is also highly recommended for most LCoS home theater models to offset their low brightness performance and capitalize on their superb native contrast.

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