LCD projectors are not conceding anything to DLP technology

Peter Putman, CTS

If you keep up on the latest front projector news, you can’t be faulted for thinking that Digital Light Processing (DLP) is getting the lion’s share of attention and that liquid-crystal display (LCD) imaging technology is old-fashioned and falling behind.

Indeed, Texas Instruments has performed two projector reliability studies in the past couple of years that imply a higher-than-expected failure rate of LCD imaging panels and their associated dichroic color filters. The first study, while newsworthy, proved to be flawed in its conclusions.

The second study ostensibly corrected those flaws and purported to show more conclusive proof that LCD imaging just wouldn’t hold up in the long term. DLP, it was claimed, would prove to be the more reliable choice in the long term for portable business and education projectors.

These studies could fairly be called self-serving. After all, there existed (and still exists) a substantial price differential between the two technologies that favored (and still favors) LCD projectors.

As usual, there’s more than meets the eye here. In December, I was invited to tour Hitachi’s LCD projector manufacturing facility in Gifu, Japan, during which time I sat in on several presentations regarding the LCD projector market and who the major players are.

In terms of overall projector sales for October of 2004, Hitachi was the clear leader, followed by NEC, Epson, Mitsubishi, InFocus, and Sanyo. These six companies accounted for 70% of the total market. Interestingly, three of them (Hitachi, Epson, and Sanyo) only sell LCD projectors, more than half of all sales in that grouping.

Hitachi’s presentation also showed three companies (#1 Epson, #2 Hitachi, and #3 Sanyo) having 37% of the worldwide market share for projectors in 2004, with the nearest competitor selling any kind of DLP product (NEC) at 10%.

Obviously price is important, but it can’t be the only reason that LCD technology continues to hold favor. Warranties and other incentives do their part. But there are advancements being made in the technology, too.

At Cedia Expo 2004, both Sony and Panasonic showed new front LCD projectors for home theater that incorporate a super-fast variable iris. The effect of this iris mechanism is to enhance black levels when showing images or video with medium to low luminance levels. Hitachi also introduced a variable iris to their current-model PJ-TX100 home theater LCD projector.

Panasonic also has made tremendous improvements to color accuracy, employing the talents of one of Hollywood’s top colorists. Sony and Hitachi have also improved the color rendering of their projectors. Sanyo, the world’s largest LCD projector manufacturer, has started including the variable iris and improved color correction in several of their new LCD projectors.

In addition, Panasonic has also made changes to their optical systems that reduce the so-called ‘screen door effect’. If you’ve ever stood close to an image from an LCD projector, you know what the ‘screen door effect’ is. Thousands of tiny LC pixels are easy to spot as they are superimposed over the projected image. Using the Panasonic system, they’re as difficult to see as the pixels on a digital micromirror device (DMD).

Sanyo’s PLV-Z3 front widescreen projector (reviewed elsewhere on this site) delivered contrast ratio numbers of 269:1 average and 462:1 peak during some recent tests in my studio. Panasonic’s new PT-AE700U widescreen projector did even better with 272:1 and 494:1 readings, respectively. These numbers are competitive with many portable DLP projectors I’ve tested.

Additional improvements have come about in optics, improved airflow, and lower fan noise. But the one area where LCD technology has always had an advantage is in the use of three imaging panels with dedicated RGB color filters, instead of a single imaging device with a sequential color wheel as small DLP projectors must do.

The color wheel often results in a rainbow artifact, caused by a combination of your eye blinking and the sequential color sequencing working together as a stroboscope. Some people don’t notice this effect (it’s most obvious with white text, lines, or shapes on the screen) but many do, including myself.

During the presentation, Hitachi also showed some studies they have done that point to short-term failure rates of the color wheel rotors and bearings in portable DLP projectors. In some cases, these failures were seen in as little as 1500 hours, about the same time interval (perhaps coincidentally) where the TI projector reliability studies claimed the blue dichroics would fail in some portable LCD projectors.

The point of all this? LCD is far from ‘obsolete’ or ‘unreliable’, and based on what I saw at Hitachi along with my tests of the Sanyo and Panasonic products, it is more than up to the challenge from DLP technology.

Need proof? You’ll likely see 1920x1080 LCD front projectors some time later this year, thanks to Epson’s new 1.65” polysilicon panels. And it’s a sure bet that those 1080p LCD front projectors will sell for less money than a comparable single-chip front 1080p DLP design – if one is even in the works for the professional market.

This 1920x1080 front LCD projector had its premiere at
Cedia Expo 2004 and will also be seen at CES 2005.

Copyright ©2005 Peter H. Putman / Access Intelligence
This article appears in the February 2005 issue of Studio Monthly magazine.