THE FRONT LINE: JUNE 1, 2005
SID 2005: LCD’S FULL METAL JACKET
Although there were many interesting and unusual technology displays at the 2005 Society for Information Display show in Boston, one thing was clear: LCD panel manufacturers are bringing out the heavy artillery.
There were numerous displays of advanced TFT LCD panels, demonstrations of LED and hybrid backlight technology, and exhibits of improved polarizing films to improve viewing angles. LCD panels and modules with 1920x1080 resolution were available for inspection in sizes as small as 37 inches and as large as 82 inches.
As the competition heats up between LCD and plasma for the consumer television market, it’s clear that major players such as LG Philips, Samsung, and Sharp are working hard to address the shortcomings of TFT LCD technology, which include color gamuts and accuracy, black levels, motion smear, viewing angles, and pixel density.
There are many ways to solve color issues, and the LED backlights employed by Samsung and LG are one way. But LEDs are current-hungry as a rule, and LCD panel manufacturers certainly don’t want to cede any ground to plasma in the area of power consumption.
Figure 1. LG Philips demonstrated this LCD monitor with conventional RGB LED stripes.
One possible solution is a hybrid backlight that employs either cold cathode or hot cathode fluorescent lamps with red, green, and blue LEDs. A demonstration of this approach was found in the LG Philips booth, and it is claimed not only to provide more accurate values of red, green, and blue, but also to conserve energy by employing the fluorescent lamp to provide white light for brighter images.
Another way to improve brightness while reducing power consumption was demo’ed by Clairvoyante. Their system adds a white sub-pixel to each RGB pixel block. It uses two subpixels per imaging pixel (one red-green combination and one blue-white) to produce just as much image brightness as a conventional RGB subpixel.
Samsung also had a new backlight system known as BLU (backlight unit). The demonstration 46-inch unit was claimed to consumer 40% less power than traditional side-scanning backlights and is also in compliance with tighter regulations on mercury and lead that will go into effect in the European Union in 2006.
Figure 2. Samsung’s BLU LED
technology is supposed to be
more efficient and also environmentally friendly.
Figure 3. Philips’ Aptura demonstration
included
this color-corrected 42-inch LCD monitor.
To improve black levels and minimize motion smear, Philips offers their Aptura scanning backlight system. This shuttered light process certainly yields better image definition with fast motion and has a real-world analogy in the mechanical shutter found in movie projectors. Without that shutter, all you’d see is a blue of frames rushing by on the screen. With it, there is a blanking interval as one frame advances to the next frame. Aptura works in a similar manner.
LG Philips also showed two ways to address motion smear. One was the scanning backlight system, and the other inserted black frames periodically to achieve the same effect as a mechanical light shutter.
Figure 4. Nitto Denko demonstrated
their latest polarizing films for LCD.
The right half of the screen uses conventional filters and
the left half uses the new ND filters.
Figure 5. LG Philips unveiled new 37-inch and 42-inch 1080p LCD modules.
The viewing angle bugaboo that has been associated with LCD may also be an endangered species. Nitto Denko had several examples of polarizing films on display that allowed off axis viewing from angles as severe as 170 degrees with no degradation in black levels, contrast, or color saturation.
Back in the LG Philips booth, three new 1080p LCD modules were unveiled in 37-inch, 42-inch, and 47-inch sizes. Samsung also showed a rack of 1080p LCD panels ranging in size from 46 inches to their latest “big boy” design, an 82-inch array which produced some very nice pictures but had noticeable brightness uniformity problems.
If you needed a suntan, Osram had an enormous LED backlight module that lit up most of one aisle. This is supposed to be the largest LED backlight available, although it was more of a concept demonstration than anything else. While it’s possible to make LCD TVs this large, the bulk of the market is looking for much smaller screens.
Figure 6. You needed SPF 60 lotion to hang around the OSRAM LED backlight demo.
Figure 7. Samsung’s 40-inch AM OLED TV now shares the ‘world’s largest’ title with Epson.
There were other technologies on display. The past few years have seen lots of hype about organic light-emitting diodes (OLEDs), but the tone this year was a bit subdued, even with all of the OLED exhibitors. Still, Samsung caught everyone’s attention with a super-thin, 40-inch AM-OLED TV that didn’t have the best image quality but was impressive in its own right.
Kodak and Universal Display had a wide array of small OLEDs out for examination, reflecting a belief that the bet market for these products will be handheld and near-to-eye displays for the immediate future. Dupont, who made a splashy entrance into the OLED business a few years back with their OLite brand, had a much simpler exhibit of moisture-resistant OLED films. This included a clever fish tank showcase containing yellow, green, blue, and orange OLED displays of (what else?) fish.
LEDs were also found in a few super-compact DLP projectors. Samsung had a palm-sized DLP projector actually making images on a small screen, using the LumiLEDs light engine. LumiLEDS was also in attendance with a similar projector, lighting up a 15-inch diagonal image from a distance of about a foot. These pocket projectors are sort of underpowered, but may find a niche for one-on-one presentations.
Figure 8. Yes, those super-tiny pocket DLP projectors with LEDs actually work!
As far as alternative and emerging displays go, perhaps the biggest disappointment was Canon and Toshiba’s failure to bring a working prototype of their 36-inch surface-conduction electron-emitting display (SED) to the show. In the U.S, the SED has only been shown publicly once (at CES 2005) and was a no-show in Toshiba’s booth at NAB, despite the presence of an SED functional diagram.
The pictures that the SED makes are outstanding and the technology behind it so intriguing that the two SED Inc. technical paper presentations on Friday morning, May 27, were jammed to the aisles. The SED, which can be likened in operation to a super-thin CRT, has lots of promise, but may ultimately fail due to the already-congested LCD and plasma markets and their vicious price wars – if the SED ever gets to market.
iFire was another disappointment. This Canadian company has developed an electroluminescent display about the same size as the SED, but all they had to show in their booth was a plastic model of their newest fabrication line and some Powerpoints from a portable projector. According to a colleague in the industry, iFire has successfully built several smaller version of this display. Why not show those?
Figure 9. Brillian is staking its
future on this 67-inch LCoS RPTV design.
Upstairs at the Sheraton, Brillian was privately showing their latest 67-inch 1080p LCoS rear-projection TV and several light engines, plus evaluation kits. The company hopes to land a major OEM deal, although their track record to now has not been encouraging. Brillian was to supply Sears with 720p LCoS HD RPTVs in a similar deal for the 2004 holiday selling season, but couldn’t make good on their delivery promises.
Perhaps the most unusual display concept on exhibit was Qualcomm’s iMod (for Interferometric MODulator), an unusual MEMS device that combines a stack of thin optical films and a reflective membrane. In the open (expanded) position, the device reflects light at a 45-degree angle, while it absorbs light in the closed (collapsed) position. The iMod provides RGB pixel imaging and can be used for near-to-eye and handheld electronics.