A stronger technology presence from Taiwan manufacturers was just one storyline that emerged at the most recent FPD International show, where new players surfaced and innovations were unveiled.
by Ken Werner
THE 69,000 visitors to FPD International (FPDI), held October 19–21, 2005 in Yokohama, Japan, saw a flat-panel-display (FPD) industry in creative ferment. Because key large-screen FPD-TV models are selling extremely well and coming ever closer to true mass-market status, manufacturers have concluded that continued success depends on sharply reducing the motion blur and expanding the color gamut in liquid-crystal displays (LCDs), in increasing the resolution of plasma-display panels (PDPs), and in reducing costs for all technologies.
At the same time, the accelerating development of multifunction mobile phones and personal media players (PMPs), and the rapidly evolving infrastructure for cellular-phone video, is inspiring makers of small- and medium-sized displays to innovate on several fronts.
It also was obvious at FPDI that innovation is no longer confined to Japanese and Korean display manufacturers. Leading Taiwanese manufacturers were also proudly showing significant technology demonstrations and prototypes, some of which will be in production this year. Interestingly, innovative U.S. and European companies have had a more obvious presence at FPDI in each of the past several years, finding it a fertile ground for potential customers and partners.
The excitement in the industry was reflected in the record participation at FPDI 2005. Total attendance increased by 11,000 compared to 2004, while the number of companies exhibiting increased from 297 to 355, said Norio Misawa, Senior Manager of FPDI 2005.
For those who were unable to make the trip to Yokohama, or for those who were there but could not see everything, here is a review of what was happening on the show floor, broken down by technology into the following five areas: LCDs, PDPs, organic light-emitting diodes (OLEDs), backlight units (BLUs), and small displays.
Liquid-Crystal Displays (LCDs)
At the Sharp booth, there was usually a line of attendees waiting to see the impressive LCD, shown at CEATEC Japan two weeks earlier, that demonstrated a contrast ratio of 1,000,000:1. The dual-view LCD technology that simultaneously shows different images on the left and on the right side of the screen was shown again, but with a much broader range of examples. The most compelling was the Fujitsu Ten Eclipse navigation system, commercialized in the summer of 2005, that shows map and navigation information to the driver and movies or other entertainment to the passenger. On a 45-in. dual-view LCD, the transition from one image to the other occurred at an estimated 15° (left and right).
VeilView, which presumably uses a variation of the dual-view technology, permits the display to be viewed normally by the user, who is directly in front of the display, but anyone trying to view the display from an appreciable angle sees either a static pattern or a black screen. At intermediate angles, it is possible to see both images superimposed (Fig. 1).
Sharp showed its very-good-looking Advanced ASV LCD modules for TV in 65-, 57-, 45-, and 37-in. sizes. The company has announced that its modules are for sale to other LCD-TV makers, but has also said it has insufficient capacity for its own needs.
Sharp has been cautious about committing to any of the "impulse-drive" approaches to reducing motion blur in LCDs. Although it is generally agreed that just making the panel response time faster cannot remove all motion blur, Sharp presented a striking demonstration of how far it can go. The company showed two LCD panels: one with a response time of 6 msec gray to gray (GTG) and the other with 4 msec. Detailed still images moved across the screens at a medium-fast speed, which is a demanding subjective test of motion blur. Surprisingly to some knowledgeable viewers, the difference was not at all subtle, with the the 4-msec panel showing much less motion blur (Fig. 2).
Samsung showed full-high-definition LCD-TV panels in the company's signature 32-, 40-, and 46-in. sizes. A 32-in. "Color-Filter-Less" LCD was well promoted before the show, and the light-emitting-diode (LED) backlit field-sequential-color (FSC) display drew large crowds. However, not everybody was impressed with this display – the largest FSC LCD ever shown, having a color gamut 110% of NTSC and a power consumption of 82 W at a luminance of 500 nits – because there was a readily noticeable flicker on the display. A staffer said that the flicker was only in the red channel and blamed it on an instability in the power supply. But Tom Credelle, Vice President of Engineering for Clairvoyante, who was a member of the crowd, believed the "flicker" was a basic color-break-up problem. Masaya Okita from Hunet Display Technology, also in the crowd, said that the 32-in. model used the inherently fast optically compensated bend (OCB) LCD mode and that a critical compensation film has been a problem in ramping up OCB in the past. However, Fuji Photo Film may be increasing production of the OCB-WV film.
Although Samsung Electronics Vice President Seongsik Shin had cited cost savings in the initial announcement of the display, Jeremy Burroughes, Chief Technology Officer for Cambridge Display Technology, wasn't so sure. Citing the current cost of the high-speed electronics and the LED backlight unit (BLU), Burroughes speculated, "The Samsung FSC is probably cost-neutral."
Frame-rate doubling is one way to implement "impulse-type addressing" for reducing motion blur in an LCD. Samsung showed a 46-in. LCD with a 120-Hz frame rate, along with another LCD using a standard 60-Hz frame rate. As with Sharp, the demonstration pattern consisted of still images moving fairly rapidly across the screen. The reduction in motion blur of the 120-Hz panel was impressive, although frame-rate doubling is widely considered to be an expensive solution.
Samsung and its competitors have recognized a demand for vertically oriented versions of their large FPDs for "information-display" applications. Samsung's demonstration was particularly impressive because it featured the company's massive 82-in. active-matrix LCD (Fig. 3).
AU Optronics's impressive Advanced Multi-Domain Vertical Alignment (AMVA) cell technology seems similar to Samsung's Super Patterned ITO Vertical Alignment (S-PVA), with both having eight domains per subpixel divided into two groups, and both delivering excellent color fidelity across a broad range of viewing angles. A staffer said the two technologies may seem similar, but AUO attains the result using its own approach – "It's our own technology," the staffer said – and AUO is definitely not a licensee of Samsung. The 32-in. version has a luminance of 500 nits, contrast ratio of 500:1, response time of 8 msec (GTG), and a power consumption of 125 W.
AUO demonstrated a variety of advanced LCDs, including a high-dynamic-contrast LCD with an LED backlight intended to increase the contrast ratio from the currently typical 1000:1, which AUO says is inadequate. It does this, in part, by reducing the light leakage in the LCD black state to 0.05 nits. In addition, the bit depth is increased from 8 to 14 bits, and the LED backlight is locally adaptive. The system produces a contrast ratio of 10,000:1, which is only suggested in the photo (Fig. 4).
Gray-field insertion (GFI) is an innovative approach to producing an impulse-addressed LCD with decreased motion blur. The basic concept is the same as that for black-field insertion (BFI), in which data producing a black field occupies approximately 50% of each frame period. However, the BFI inevitably reduces luminance if other parts of the system remain unchanged. With GFI, a gray field whose luminance is matched to the average picture level of the video content is used instead of a black field. As a result, the luminance is unchanged. AUO says GFI cuts the motion-picture response time in half and has no negative impact on cold-cathode fluorescent-lamp (CCFL) lifetime. AUO's GFI system attains a response time of 4 msec GTG, which the company says is optimal. Dany Liu, a Senior Engineer in AUO's Lighting System R&D Lab, said that a GFI panel will probably be a product in the first half of 2006.
Ken Werner
Fig. 1: Sharp's VeilView permits the display to be viewed normally by a user positioned in front of the display (left), but anyone trying to view the display from an appreciable angle sees either a static pattern (right) or a black screen.
Chunghwa Picture Tubes (CPT), Taiwan's third-largest LCD manufacturer, showed a full range of LCD panels, including 26-, 32-, and 37-in. LCD-TV panels with 8-msec GTG, the de facto standard for a competitive high-quality TV panel at the time of FPDI 2005. More interestingly, though, was a display wall demonstrating CPT-developed advanced technologies. Among them were fast (5 msec) and ultra-wide-view technologies for twisted-nematic (TN) LCD panels, the type used in notebook PCs and desktop-computer monitors.
A 32-in. "OCB-Movie" LCD panel offered excellent control of motion blur using Offset Codebook (OCB) mode and both BFI and frame-rate doubling for impulse drive, said Chien-Lin Pan, an engineer in CPT's Mobile Product Design Division. Considering the current state of development, it is not surprising that yields on the panel are still low.
CPT also showed an impressive panel based on National Semiconductor's point-to-point differential signaling (PPDS) architecture and supporting chip set, which features a 10-bit color depth and independently adjustable gammas for red, green, and blue (Fig. 5). In an aisle on the show floor, Dick McCartney, National Semiconductors's principal display technologist, said the company will be able to make several announcements of PPDS design wins in commercial panels during 2006.
At IMID in Seoul in July 2005 (and again at this show), Samsung put one of its new advanced S-PVA LCD panels on a turntable so it could be viewed easily from many angles. This was done in large part to counter LG.Philips's previous claims of better color fidelity over a wide range of viewing angles.
Fig. 2: Sharp demonstrated that an LCD with a 4-msec (GTG) response time (left) can have significantly less motion blur than one with a 6-msec (GTG) response time (right).
At FPDI, LG.Philips entered the turn-table war by using one to mount one of its Enhanced Super In-Plane Switching (S-IPS) LCDs. The Enhanced S-IPS has a response time of less than 5 msec GTG compared to less than 8 msec for the older S-IPS technology; less than 10-msec MPRT vs. less than 16-msec MPRT for the older version; 178° viewing angle vs. 140°; a contrast ratio of 1000:1 vs.600:1; and a black-level luminance of 0.6 nits or less vs. 0.8 nits or less. Although this is a very-good-looking display with excellent wide-angle viewing, the Enhanced S-IPS technology still does not have black levels as low as the those currently obtainable with advanced S-PVA. Perhaps in acknowledgment of that, LG.Philips was showing images that stressed mid-tones.
The company was pushing the availability of full-HD (1080-line) panels in a variety of sizes, subliminally making the point that full HD is still restricted to larger sizes in plasma technology. LG.Philips also showed an attractive high-color-depth (12-bit) 42-in. panel and a 120-Hz frame-rate-doubled panel that effectively reduced motion blur.
Toshiba Matsushita Display (TMD), although best known for small- and medium-sized displays, was showing 23- and 32-in. versions of its fast OCB blinking-backlight low-temperature polysilicon (LTPS) LCD-TV panels. At SID 2005 in May, TMD's North American marketing arm could not yet say which high-end manufacturer was incorporating the low-blur panel into its TV sets. At FPDI, the jig was up: an Eizo 23-in. LCD-TV was on the TMD stand.
For the first time in my experience, SVA-NEC – the joint venture between SVA Electronics of Shanghai and NEC – showcased its display product line at an international exhibition. There were 15-, 17-, and 26-in. panels, along with an SVA LCD-TV set. There were also some interesting small panels, which will be discussed later.
Hitachi showed its IPS-Pro LCD modules, which feature enhanced luminance and black-data insertion (BDI) for reduced motion blur. A 32-in. example was shown in a Panasonic Vieira LCD-TV (Model TH32LX500).
Fig. 3: FPD makers have recognized a demand for vertically oriented versions of their large panels for "information-display" applications. Samsung's vertical 82-in. AMLCD demo was particularly impressive.
Chi-Mei Optoelectronics (CMO), Taiwan's second-largest LCD manufacturer, showed a variety of new technologies, including an LCD panel with an LED BLU and image-control engine. According to CMO, LED BLUs can sometimes deliver their expanded color gamuts at the cost of over-saturated colors – unless they are coupled with a good color-management system. In this panel, CMO performs the color management with its own image-control engine. The panel has a 100% NTSC color gamut, an impressive contrast ratio of 10,000:1, dynamic gamma-curve control, and "real color recovery technology." The average response time is 4-msec GTG. The company was also implementing low motion blur with a scanning BLU and with high frame rates.
For color-gamut expansion, CMO was showing multi-primary displays with RGBW, RGBY, and RGBYC primary sets. All of these systems improve color gamut and luminance simultaneously. CMO is working with Genoa Color Technologies, but said it has developed the three- to four-color transformation algorithm for the RGBY display independently.
Plasma-Display Panels (PDPs)
Because the Korea Electronics Show was held on the week between CEATEC Japan and FPDI, the major Korean panel manufacturers gave CEATEC a pass. That gave Pioneer the opportunity to introduce its 50-in. full-HD (1080-line) PDP before Samsung SDI could. But Samsung made up for that in Yokohama, where it also showed its 63-in. full-HD PDP.
Also on display was a 42-in. HD PDP "complementary-colored" panel, which uses blue dielectric and brown-colored barrier ribs, creating the effect of a black matrix. The result, SDI explained, is enhanced bright-room contrast (more than 150:1), a 19% reduction in background luminance, reduced halation distance, and reduced materials cost.
Also shown was another 42-in. HD-PDP with an advanced film filter replacing the conventional glass filter. Benefits include less weight and thickness, less reflectance (higher bright-room contrast), less light scattering, deeper effective black level, and reduced development cost.
Dong Myung Lee, Senior Engineer for Samsung, said the advanced film filter and complementary-colored panel will be in production within 12 months for a combination of better performance and a 25% cost reduction on the panel. The 50-in. full HD will be in production late next year, but the 63-in. full HD will be out first.
Samsung Principal Engineer Minsun Yoo was seen looking at the 50-in. full-HD panel fondly, and she expressed great satisfaction at seeing it exhibited at FPDI. Making a full-HD PDP as small as 50 in. is not easy, as she outlined in a technical paper given at IMID in July 2005.
Pioneer showed its full-HD 50-in. PDP and a range of panels using the company's "P.U.R.E. Black" technology. To many, Pioneer's contrast and overall picture quality remain the standard of comparison for plasma displays – as does the premium pricing.
Fujitsu Hitachi Plasma (FHP) Display, 80% of which is now owned by Hitachi, displayed a plasma display and a presumably equivalent LCD side by side. The PDP's colors were clearly richer. (One should always be cautious of comparisons in which one side controls all the variables; still, the 72% color gamut of most currently available LCD-TVs is a relatively easy target. That is one reason gamut expansion is such a hot topic among LCD manufacturers.)
Fig. 5: Chunghwa Picture Tubes' AMLCD panel based on National Semiconductor Corp.'s PPDS architecture (right) exhibited richer colors and more subtle color gradations than a conventional panel (left).
FHP also displayed a range of panels. Particularly interesting, although not new, was a 32-in. alternate lighting of surfaces (ALiS) PDP with 852 x 1024 pixels and 1100-nits white peak luminance. These ALiS pixels are not directly comparable to ordinary pixels because they use each sustain line to alternately drive the pixels above and below it, so this ends up being a type of interlacing. More to the point, it is a way of designing a relatively small-screen plasma display, with pixel areas large enough to be reasonably bright and efficient.
Still, 32 in. is pretty small for a 1024-line display. The luminance is good, but perhaps it is significant that luminous efficiency and contrast were not listed on the specification card. PDPs this small are not found in the North American market, and high luminance and high efficiency become much harder to achieve as plasma pixels become smaller.
LG Electronics was trumpeting its 71- and 60-in. full-HD PDP TVs, each a "world's first" in terms of commercial products. The 60-in. PDP uses the company's Gen 4 cell structure, which contributes to improving the luminous efficiency from 0.7 to 0.97 lm/W. This generation incorporates a closed cell structure and a "new gas."
LG Electronics also demonstrated the "world's first" use of single scan in a 50-in. PDP. (Since other companies, including Pioneer, have also shown single-scan 50-in. panels, "world's first" may require careful definition.) The exhibit made clear that the simplification and component reduction of single scan is substantial (Fig. 6).
Organic Light-Emitting Diodes (OLEDs)
In a suite off the show floor, Cambridge Display Technology (CDT) was showing a 14-in. active-matrix polymer OLED (POLED) with 1280 x 768 color pixels, which was fabricated with ink-jet printing. The panel drew a steady stream of high-level visitors from major display companies. CDT's Burroughes made a convincing case that in 2006, the materials, device-design, and manufacturing-equipment infrastructures will all reach the degree of maturity needed for POLEDs to have a substantial roll-out in 2007. Essential elements of this infrastructure are the Sumation joint venture with Sumitomo Chemical for manufacturing POLED inks for ink-jet fabrication, and CDT's selling of the remaining 50% of ink-jet-printer-manufacturer Litrex to partner ULVAC.
Samsung's 40-in. WXGA active-matrix (AMOLED) display, which uses "color by white" technology and amorphous-silicon TFTs, is no longer a novelty. As shown in Yokohama, the panel had a scattering of dead pixels. A Samsung engineer said this was a result of making the panel on an R&D line that permitted moisture contamination of the OLED cells during fabrication. For TV products, the display lifetime would have to be 50,000 hours, he said, and more materials development is needed before that level can be reached.
A wide variety of small passive-matrix and active-matrix OLED displays could be seen on the show floor. TMD announced the beginning of mass production of its presumably LTPS-based 3.5-in. QVGA AMOLED and showed multiple panels, along with a prototype OLED viewer (Fig. 7).
Toppoly Optoelectronics's 7-in. 800 x 480 bottom-emission color AMOLED using an LTPS active matrix stood out, if only for its relatively large size; luminance is 200 nits and contrast is 1000:1 in a dark room and 100:1 in a 500-lux ambient environment (Toppoly deserves a lot of credit for supplying both numbers). The color gamut is greater than 40% NTSC.
Hitachi and Chi Mei Optoelectronics showed small AMOLEDs. Hitachi's was 2.5-in. on the diagonal; CMO's was 2.2 in. Chunghwa Picture Tubes showed a 2.2-in. AMOLED, which is only a technology demonstrator for now.
Backlights
For the most part, large LED backlight units (BLUs) still are considerably more expensive than traditional CCFL BLUs, but that is likelyto change quickly. The sharply enhanced color gamut possible with LEDs is very appealing. As a result, LED BLUs could be seen all over the show floor. A less-expensive way of expanding gamut is to reformulate the phosphor mix in CCFLs, and some of these were displayed as well.
Fig. 6: LG Electronics's exhibition showed clearly that single-scan addressing (right) – addressing all the pixels on a plasma display from the bottom of the panel – is much simpler and, therefore, less expensive than conventional dual-scan scanning (left).
But even current CCFL BLUs are among the most expensive components in a large LCD, so a parallel but less-developed trend is the exploration of less-expensive backlight technologies. At the moment, that points to flat fluorescent lamps (FFLs).
Samsung showed a 46-in. LCD-TV module with an LED BLU based on the company's "Xmitter" technology, which, it claims, has the lowest power consumption of any LED BLU. One result is that the LCD module requires no fans or heat sinks. The entire module consumes 220 W, has a gamut of 107% NTSC, and a luminance of 500 nits.
AU Optronics described an FFL BLU with greater than 80% luminance uniformity and a high-gamut CCFL BLU that exceeds 90% NTSC by modifying both the lamp phosphors and the matrix color filter. Also described was a 23-in. RGB LED BLU that produces 380 nits through the LCD panel while consuming just 68 W. The unit is no thicker than a conventional CCFL BLU. AUO's Dany Liu said the company is obtaining its LED BLUs from a Taiwanese supplier, but the units are still expensive.
LG.Philips showed an ultra-slim direct CCFL BLU designed for monitors. The unit has a wide gamut thanks to reformulated phosphors and uses improved optical films to reduce the air gap. Also shown was a 47-in. low-power LED BLU that leads to a module power consumption of 270 W, but less is expected in 2006. The unit could be in a product by Q2 '06.
Chunghwa Picture Tubes showed a "dynamic color control" LED BLU that uses optical feedback to correct for changes in color balance or luminous output as the BLU's temperature rises with extended use. A 37-in. TFT-LCD module with such an LED BLU consumed 350 W (module power). They also displayed a 37-in. "plasma backlight," which is what the company calls its FFL BLU. The unit produces 10,000 nits with a luminous efficiency of 35 lm/W and 88% uniformity.
Korean LED manufacturer Seoul Semiconductor was showing a range of complete backlights powered by either white or RGB LEDs, the first complete BLUs from this company.
Philips was showing its Aptura™ scanning hot-cathode fluorescent-lamp (HCFL) BLUs in a variety of sizes and was demonstrating the technology's ability to sharply reduce motion blur to good effect. Tama Fine Opto was showing BLUs based on CCFL, FFL, and FLED, a technology for making flat LED BLUs much thinner by nesting down-firing LEDs in a carefully designed optical well that reflects the light upward in parallel rays. The FLED is "flat" in the sense that the LEDs are flush with the top surface of the BLU's substrate.
OSRAM had its 21.3-in. Planon2™ FFL, for which it was claiming a 100,000-hour lifetime, and a variety of LEDs intended for use in customer BLUs.
Small Displays
System on Glass (SOG), in which circuitry other than switching transistors is fabricated directly on the display's glass panel, is one of today's watchwords in small-display design.
TMD drew crowds with SOG displays that sensed light-pen inputs and the image of a finger approaching the display. This "finger-sensing input display" acts like a touch display, even though the touch is only inferred from time-based image analysis. Although these displays were crowd-pleasers, a 2.4-in. QVGA-VGA convertible display for cell phones could be more significant in the near term. This display can exhibit VGA (at 332 ppi) for high-resolution images, such as photos or maps, and can switch to QVGA (at 166 ppi) for lower power consumption or compatibility with, for instance, cellular-phone TV images. TMD parent Toshiba claims it is the leading supplier of mobile-phone displays.
SVA-NEC also presented its SOG capabilities, including a lenticular 2-D/3-D display. Principal Researcher Takanashi-san of SVA-NEC's SOG Research Labs said that the display divides each subpixel in two. When the signal to each part of a divided subpixel is the same, a 2-D image is seen; otherwise, the image is 3-D, making it possible to display 3-D icons and images on an otherwise 2-D screen with no switching between 2-D and 3-D. Also on display were a 4.1-in. 800 x 480 SOG prototype with an expanded color gamut of 110% NTSC and a 2.5-in. SOG 2-D/3-D prototype with horizontally double-density pixels (HDDP).
Samsung also had a QVGA-VGA convertible display – this one with a 2.22-in. diagonal – and a 2.2-in. LTPS QVGA.
Clairvoyante is extending the reach of its Pentile™ technology, showing Pentile AU Optronics, Chunghwa Picture Tubes, and BOE-Hydis displays in its booth. In its own booth, Wintek was showing a 1.8-in. QVGA cellular-phone display clearly labeled "Pentile L6W." Clairvoyante CEO Joel Pollack said that the company has a dozen or so licensees and will be able to announce products in 2006.
Hitachi showed a small display with a "depth-fused 3-D visual illusion system," which fused images from two displays, one in front of the other, to create an effective 3-D illusion.
In general, makers of large flat panels for TV sets worry about gamut expansion. But with photographs being viewed on cellular phones and other portable devices in large numbers, and with cellular-phone television beginning its roll-out, wide-gamut small displays may be in demand soon. Sanyo and Epson are seriously exploring this space with their Photo Fine Chromarich technology, a four-primary system that adds cyan to modified red, green, and blue primaries. The companies showed a cellular-phone-sized display with 100% NTSC and a 4.5-in. VGA display with 108% NTSC for portable media players. Chromarich could be in products by thesecond half of 2006, a staffer said, but it is not definite. The cost might be slightly higher than a conventional display, he added.
Sanyo and Epson also showed a switchable 2-D/3-D display with a twist. The display can be used like Sharp's dual-view display (two viewers see different 2-D images from different angles), but each viewer can also watch the same 3-D image, or they can use the display in conventional 2-D mode. •
Fig. 7: TMD announced the mass production of a 3.5-in. QVGA AMOLED display and showed the new display in a prototype viewer.