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Perhaps it was inevitable, but Epson has jumped on the reflective LCD imaging bandwagon. Joining liquid crystal on silicon (LCoS) panel manufacturers Sony and JVC, Epson has come out with a new reflective high-temperature polysilicon (HTPS) LCD chip for home theater projection.

This device (pictured below) measures .74 inches diagonally, and offers full 1920×1080 pixel resolution. Two new projectors have already been shown at the IFA show in Berlin that incorporate these panels.

Epson's new .74" 1080p reflective LCD chip.

How is this new technology different from conventional HTPS LCD? What’s changed is that polarized light rays do not pass through the panel, but are reflected back out the way they came in, albeit at a different angle. This is the same way that LCoS imaging works – the light enters and exits the panel at different angles.

While this approach makes for a more complex polarized beam splitter to combine the individual red, green, and blue images, it also places the controlling semiconductors out of the optical path, behind the individual pixels. That, in turn, means each pixel’s aperture, or available imaging area, is enlarged.

As a result, the portion of each pixel actually used for imaging – its fill factor – also increases. Indeed, the ‘pitch’ of each pixel on these new chips is about 8.5 um (micrometers), larger than that found on the company’s latest D7 HTPS chips. In fact, Epson is claiming an improvement of 40% in fill factor with this new technology, which is also supposed to handle fast motion with less blurring.

Here's how reflective HTPS LCD works. A conventional HTPS LCD chip is shown on the left. (Image courtesy Seiko Epson)

Home theater enthusiasts generally prefer the look of LCoS projection because it most resembles film in the way the liquid crystals respond over a grayscale ramp with changes in driving voltages.

While DLP also does an excellent job here, it can appear noisy at times when showing filmed content. (Stand close to a screen with projected DLP images on it, and you’ll see what I mean.) Liquid crystal response is very much analog, while DLP is a pulse-width modulated (PWM) digital imaging process.

The new projectors rolled out at IFA are the EH-R2000 (about $4,600 USD) and EH-R4000 (about $7,600 USD). Both use three-panel (RGB) engines with these reflective HTPS panels, and both are scheduled to ship in November of 2010.

Epson's RH-2000 is one of two new home theater projectors that will use reflective LCD imaging technology.

Is LCoS going to be a bigger player in home theater projection? Probably, although it still commands a significant price premium over single-chip DLP and conventional 3LCD. You can buy some pretty good 3LCD boxes for $1,300 now, and single-chip DLP HT projectors have slipped under the $1,000 barrier.

The fourth Japanese manufacturer of LCoS – Canon – so far hasn’t tipped their hand with any plans to enter the 1080p front projection arena. But I wouldn’t rule them out.

Posted by Pete Putman, September 10, 2010 8:41 AM

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About Pete Putman

Peter Putman is the president of ROAM Consulting L.L.C. His company provides training, marketing communications, and product testing/development services to manufacturers, dealers, and end-users of displays, display interfaces, and related products.

Pete edits and publishes HDTVexpert.com, a Web blog focused on digital TV, HDTV, and display technologies. He is also a columnist for Pro AV magazine, the leading trade publication for commercial AV systems integrators.