Displays Add a Dimension, Durability

Melinda Rose, Senior Editor, melinda.rose@photonics.com

The rumblings about 3-D that began in 2009 are starting to hit the home display market in earnest, thanks in part to the overwhelming popularity of 3-D movies such as Avatar. Besides being visually more stimulating, new displays also are becoming more interactive through multitouch technology, and much thinner and lighter with the addition of LED backlights. Also, various types of organic LED (OLED) technology are gradually penetrating the display market, although currently only at small and medium screen sizes.

“Make no mistake about it – consumers are ready for 3-D,” Sony Electronics President and Chief Operating Officer Stan Glasgow told a crowd at the business conference during the Society for Information Display’s (SID) Display Week in Seattle in May.

Sony expects demand to be strong for its 3-D Bravia TVs this summer, he said, and predicts it will sell 100 million 3-D units globally over the next three years.

Sony's battery-powered 3-D active shutter glasses work with its Bravia 3-D TVs. They retail for about $150. Courtesy of Sony.

“There’s a very bullish feeling at Panasonic on 3-D,” said Peter Fannon, vice president of corporate and government affairs for Panasonic Corp. of North America, which released its first 3-D TV, a plasma display, in March.

Market research firm DisplaySearch has increased its 2010 forecast for 3-D-capable TV shipments and predicts that the market will grow from 2.5 million sets this year to 27 million in 2013.

“In 2009, we saw the first 3-D-capable TVs, with the market greatly accelerating at CES [Consumer Electronics Show] 2010. Now we are seeing the hype turning into real products,” said Paul Gray, director of TV Electronics Research at DisplaySearch.

Companies such as LG, Panasonic, Samsung, Sony, Toshiba and Vizio have all introduced 3-D-capable TVs this year.

But will the consumers who are content to put on the glasses for a few hours during trips to the movie theater really want to watch TV like that at home?

“There are a lot of question marks about 3-D in general. This is very much a ‘work the bugs out’ year, and there will be a lot of bugs to work out,” said Chris Chinnock, founder and president of market research firm Insight Media, at a Display Week 2010 press and analyst breakfast.

Shutter versus polarized

The 3-D TVs on the market today operate with either shutter-type or polarized glasses.

Shutter glasses are battery-powered, with the shutter opening and closing to show the image to one eye and then the other; polarized are just that – polarized in different directions to allow images to shift between eyes. Shutter glasses allow the images to be seen in full high-definition resolution, while polarizers show images at half the screen resolution. Shutter glasses are more expensive for the consumer but cheaper for the display manufacturer, because less cost is added to the TV when active shutter technology is used.

The 42-in. autostereoscopic 3-D display by Philips uses the 2D-plus-Depth format, including Declipse, with gives additional occlusion information for a real 3-D "look around" effect. Courtesy of Philips.

The problem with the glasses is that compatibility between brands can be an issue, and sets and glasses often aren’t bundled together. Typically, consumers get only one pair included with a TV and have to pay extra for additional pairs. The quality of the glasses also can vary greatly.

Look, Ma, no glasses!

Some prototype sets on display at SID Display Week by companies such as LG Electronics and Samsung didn’t require the use of any glasses to see the 3-D effect, although the images were far from perfect and the viewing angles extremely limited, so taking a mere step left or right of direct center could make the image blur.

During his keynote address, Steven Bathiche, director of research for Microsoft Corp.’s Applied Sciences Group, discussed the company’s wedge optics, which could create a glasses-free stereoscopic 3-D effect for the user.

The wedge lens, about 11 mm thick at the top and tapering to 6 mm at the bottom, guides light provided by an LED backlight to the viewer’s eyes. The technology uses a camera to send different images to a person’s left and right eyes for a 3-D picture, or it can send two completely different 3-D images to two people watching the same display, allowing each person to have his own unique and private experience. Right now the system’s viewing angle is only about 20°, Bathiche said, but he hopes to increase that to 40° by improving the lens design.

Osram Opto Semiconductor's Oslon LX LEDs, 1-W LEDs for backlighting LED displays, pack almost 80 percent of their light into the lightguide with the aid of an optimized lens, allowing the display to be made ultrathin and uniformly illuminated, even with single-side injection. Courtesy of Osram Opto Semiconductor.

Also at Display Week, 3M of St. Paul, Minn., showed its field-sequential 3-D optical film, which allows 3-D autostereoscopic viewing without glasses on handheld devices such as mobile phones and gaming units.

Using directional backlight technology, left and right images are focused sequentially into the viewer’s eyes, enabling a full-resolution display. The film, which requires one LCD panel operating at a 120-Hz refresh rate, can be integrated into the backlight module, the company said.

Where’s the three-dimensional beef?

OK, so you’ve made the investment in a 3-D-capable set, you have the proper gear required by your cable or satellite provider, and you have your glasses. Now – what are you going to watch?

There’s precious little programming available in 3-D these days. Gaming and sports, along with nature programs, are expected to be the big three in terms of future 3-D broadcast programming, according to industry analysts, but that programming is just beginning.

At the E3 Expo in Los Angeles in June, game makers such as Sony Computer Entertainment and Nintendo unveiled 3-D games. Sony games, which run on a Playstation 3 that has been updated to process stereoscopic 3-D graphics, require players to wear glasses. Nintendo’s 3DS system is glasses-free.

Also at E3, Microsoft premiered its Kinect for Xbox 360, a controller-free gaming platform formerly known as Project Natal. Kinect’s camera controller allows players to wirelessly use their entire bodies in game play.

On broadcast TV, April’s 2010 Masters golf tournament was available in 3-D for the first time, as were 25 matches of the 2010 FIFA World Cup in the US via the new ESPN 3D channel. DirecTV also will broadcast the first Major League Baseball games in 3-D in July, as well as its 2010 All-Star Game on July 13.

DirecTV announced it would launch three 3-D channels in June with partner Panasonic, including on-demand, pay-per-view and 3-D “sampler” channels.

But watching 3-D TV may be more complicated than some consumers realize.

“Because it’s coming first in movies, [consumers] start with a completely immersive experience, which they won’t begin with at home,” said Rhoda Alexander, director of monitor research for market analyst iSuppli. “The glasses are a major hurdle. Ultimately, [the technology] needs to be glasses-free for 3-D to cross over into the mainstream.”

“It’s not plug-and-play by any means,” agreed Chinnock, who added that consumer expectations and enthusiasm for the technology have been set too high by the ease of the cinematic 3-D experience.

“It will be the ‘era of disillusionment’ which we enter soon,” he said.

Do you wanna touch?

There are more than a dozen touch screen technologies, including resistive, projected capacitive, surface capacitive, infrared and optical imaging.

The choice of technology used often is dependent on the application and the size of the screen, but “no touch screen technology is perfect,” said Dr. Jennifer K. Colegrove, director of display technologies for DisplaySearch. Resistive and projective capacitive together own 81 percent of the touch-screen market.

Resistive screens contain parallel layers of conductive material. The bottom layer is usually printed on a stiff material, such as glass, while the top layer, the layer the user touches, is printed on a flexible material such as plastic film. The user touches the top layer with either a stylus or his finger, bending the flexible film until it touches the bottom layer and changes the resistance of the layers.

Projected capacitive screens also contain the two conductive layers, but they are sealed between two sheets of glass. The user interacts with an electric field, so the conductive layers don’t need to touch. This makes the screen more durable than the resistive type, but, unlike resistive, it can’t be used with a stylus or when the user is wearing thick gloves.

Resistive screens currently represent 50 percent of the market and are being manufactured by 90 of the more than 190 touch-screen suppliers worldwide, Colegrove said. However, DisplaySearch forecasts that projective capacitive, now at 31 percent, will become the leading touch technology this year, based on revenue. Projected capacitive technology is used in products such as Apple’s iPhone, iPod Touch and iPad, and in the Motorola Droid and other smart phones.

Touch-screen shipments rose from 468 million units in 2008 to 600 million in 2009, a surge of 29 percent. Touch-screen module revenue was about $3.6 billion in 2008, and DisplaySearch forecasts it will hit $13 billion by 2016.

Emerging applications such as e-books, slate PCs and pocket projectors will boost the touch industry this year, Colegrove said, with projected capacitive touch, optical imaging and the high transmittance type of touch technologies benefiting most.

What the touch industry still needs are scratch-resistant, hard-coated plastic and wear-resistant, antismudge, antireflection coatings, according to Gary Barrett, chief technology officer of Touch International, which, with partner DMC, produces more than 500,000 touch screens a month at seven plants.

Trends in touch

New trends in the touch industry include gesture recognition, sunlight readability, pen and finger control, on-cell (built outside the display, typically on the surface of the color filter substrate, beneath the polarizer), in-cell (built inside the display, typically between the thin-film transistor and color filter) and multitouch options.

3M Touch Systems Inc. announced its 20-finger multitouch display during Display Week. The projected capacitive display is capable of a response time of less than 6 ms for 20 simultaneous touches. Applications for the technology include computer-aided design, digital signage, computer gaming and security monitoring systems.

Haptic (from the Greek “haptesthai,” to touch) features, which allow the user to feel vibrations, clicks and other sensations, were available in more than 30 percent of touch-screen phones shipped in 2009, said Christophe Ramstein, CTO of Immersion Corp. of San Jose, Calif.

The latest trend in haptic performance is HD haptics, Ramstein said, which deliver increased fidelity via piezoactuators. The actuators provide powerful, crisp and instantaneous feedback effects via a wide bandwidth (50 to 350 Hz) and have superior effects isolation because the actuator can be mounted to the touch screen instead of the housing.

GestureTek of Sunnyvale, Calif., makes gesture-recognition technology that enables touchless display control such as that demonstrated by Tom Cruise in the movie Minority Report.

Corning unleashes the beast

“Glass breaks … why don’t you fix that?” is what Corning Inc. technologist Bill Decker said to Research and Development Director Bill Armistead about 50 years ago, according to company lore. Armistead soon launched “Project Muscle,” which led to the development of a glass made ultrastrong through a proprietary chemical process. The material, dubbed Chemcor, wouldn’t crack or break, even when bombarded with frozen chickens propelled at high speeds.

Although the material was used in the 1960s for aircraft, train and car windows, and in Corelle tableware, it proved too strong for some applications and was shelved.

Four decades later, Corning began receiving calls from cell phone manufacturers looking for a more rugged replacement to the easily scratched plastic covers the industry had been using for ~10 years.

In 2005, Corning researchers began to explore whether Chemcor, now called Gorilla glass, could be made sufficiently thin (and therefore lighter weight) for cell phones and other displays while also retaining its strength.

In 2007, they developed a composite of the glass that could be produced with a flawless surface in high volume while still being very thin. After that demand was met, they began tweaking the formula to fulfill calls for glass that is environmentally friendly.

Gorilla glass is green because it contains no heavy metals, Corning said, yet it has at least twice the strength of chemically strengthened soda lime glass at half the thickness. It is amazingly scratch- and impact-resistant; Corning videos demonstrating the glass’s durability (such as a remote control hitting it at 65 mph and leaving nary a mark) have gotten thousands of hits on YouTube. Also, because it is stable at half the thickness of regular display glass, it is surprisingly flexible.

Gorilla is the cover glass of choice in 85 high-end notebook computers, mobile phones and other portable electronic and touch-screen-enabled devices on the market currently, such as the Droid, the iPad and the Dell Streak. More than 50 other products are expected to be released over the next six months, Corning said.

Because it is thinner than LCD and touch sensor glasses, in the future it can enable smaller and lighter devices that are more durable, Corning said. For example, LCD panel weights can be reduced up to 60 percent by thinning the cover glass from 0.7 mm to 0.3 mm, or about the thickness of three sheets of copier paper. And because Corning’s glass is so strong, it can cover the entire panel, eliminating the need for a frame.

The technology also is becoming a profit powerhouse. Gorilla glass could become a $1 billion business within a few years, Corning CEO and Chairman Wendell Weeks announced in the company’s 2009 annual report. The company said it expects Gorilla glass to boost sales in its Specialty Materials segment by up to 25 percent for the second quarter of 2010.

LEDs hit the backlight

For the home flat panel market, LED backlights are turning out to be a “must have” feature for LCD displays in 2010, not only because they make the displays thinner and lighter, but also because they can improve picture quality.

LEDs have been replacing cold cathode fluorescent lamps (CCFLs) as backlights in LCD panels at an ever-increasing pace and are expected to surpass CCFLs in 2012, according to industry experts. In smaller displays, such as notebook computers, the shift to LEDs has been very quick, thanks to demands in that market for ever-lower power consumption and for thinner and lighter computers. Notebook PC market penetration for LED back-lights is expected to be 100 percent by the end of 2010 or the first quarter of 2011, according to DisplaySearch.

As solid-state light sources, LEDs are brighter, thinner and more durable than fluorescent lamps and do not contain mercury. They also provide a wider color gamut, consume less power and last longer.

There are two types of LED backlight configurations in LCDs: edge and direct. Edge-lit backlights, placed around the perimeter of the display, are thinner and require fewer LEDs, making them more cost-effective and more efficient. But they require a lightguide panel and a prism and have a problem with brightness uniformity. Direct-lit backlights, placed across the back of the display, can be locally dimmed, meaning that, as the picture warrants, LEDs in different areas of the panel can be shut off to improve contrast. But direct-lit backlights are thicker, use more power, generate more heat and require more LEDs, so they cost more to produce. Direct-lit backlight panels produce a picture that better competes with the rich colors and deep blacks of plasma screens while consuming much less power than plasma, but they can’t yet come close to competing with plasma in price.

Global Lighting Technologies' edge-lit LCD TV backlight uses only 96 LEDs on each side, for a total of 192. Courtesy of GLT.

Reducing the cost per lumen is very important for LEDs to dominate the TV market.

“LEDs are good at delivering a lot of light. They are very bad at delivering cheap light,” said Jonathan “Jed” Dorsheimer, principal of equity research for Canada’s global investment firm Canaccord Genuity.

Because of LED supply constraints and costs, edge-lit models will dominate until sometime in 2014, when direct-lit will increase as LED supplies increase, according to IMS Research.

San Bruno, Calif.-based startup Pixel Qi’s display technology allows the backlight to be turned off when not needed. The company won silver in the 2010 SID Display of the Year awards for its 3Qi multimode LCD, which can deliver all the advantages of a standard backlit LCD, such as full-color and full-motion video, but which also has a reflective mode that can turn the backlight down or off in high ambient light levels, for a power savings of about 80 percent. Pixel Qi recently began production on its first product, a 10.1-in. e-paper screen with color and video for netbooks, multitouch tablets and e-book readers.

3M showed its 22-in. projected capacitive 20-finger Multi-touch Display M2256PW (left), and energy-efficient films for TVs, monitors and notebooks (right), along with its glasses-free 3-D film for handhelds, during SID Display Week 2010. Courtesy of 3M.

Another trend in backlights is to not have one at all. Qualcomm’s proprietary mirasol display is a MEMS (microelectromechanical system) that reflects light using an interferometric modulator, so that specific wavelengths interfere with each other to create color. The San Diego-based company’s technology – which it says is based on the same principle that gives a butterfly’s wings their shimmer – consumes little power and features screens with high reflectivity of ambient light, meaning that they are easily viewable in conditions such as bright sunlight. In fact, in the outdoors, where a backlight isn’t needed, the company says its display could have 10 to 100 times the battery life of LCD displays.

Qingdao Hisense Communication of China and Qualcomm partnered on the Hisense C108, the first cell phone to feature a Qualcomm mirasol display that can be seen even in bright sunlight. Courtesy of Qualcomm.

The first smart phone to incorporate a mirasol display, the V112, was announced in February 2008 by Inventec Corp. and was featured at the GSMA Mobile World Congress 2008 in Barcelona, Spain. That same month, Qualcomm announced a deal to develop mirasol-enabled handsets for LG Electronics. The first mirasol-based e-reader display is expected to hit the market later this year.

Displays go organic

Other trends in display applications include using organic LEDs (OLEDs), which emit their own diffuse light without the need for an additional backlight and which can be viewed at angles up to nearly 180°. OLED revenues will grow to more than $5 billion in 2016, up from $600 million in 2008, according to DisplaySearch, with mobile phone displays continuing to lead the market with $2.5 billion in revenue in 2016. TV will be the second-largest application in 2016.

There are a number of small-size (11 and 15 in.) OLED displays available on the market, but the backplane used is costly and challenging to mass-produce.

Active-matrix OLEDS (AMOLEDS) have advantages over thin-film transistor (TFT) LCD panels for 3-D viewing because the left and right images can be separated completely, but breakthroughs in TFT backplanes and color patterning are needed to move AMOLEDs to large sizes, DisplaySearch said. The market for small sizes is gearing up, however. DisplaySearch estimates that about 20 new AMOLED production lines will be installed or upgraded in the next three years.

As with OLEDs, AMOLEDs are self-emissive (emitting their own light when electricity is applied) and very green (mercury-free). AMOLEDs have a fast response that is 1000 times better than plasma panels and TFT-LCDs. Their benefits for 3-D include the fact that the stereo images can be separated perfectly, frame by frame, sequentially. TFT-LCDs use a line-by-line progressive technique, which means there is some crosstalk, or ghost images, when there is a delay in switching the images between eyes. The less crosstalk, the better the 3-D effect.

AMOLED technology also is the next big thing in mobile displays, said Dr. Sang-Soo Kim, Samsung Mobile Displays executive vice president, in his Display Week keynote address.

The company, which started AMOLED production in 2007, announced in May that it will invest an additional 2.5 trillion won (approximately $2 billion) to develop the largest AMOLED display manufacturing plant in South Korea. The new Gen 5.5 (1300 x 1500 mm) AMOLED line will be established by 2012, with a capacity of 70,000 phone panels per month.

Kim said Samsung Mobile is forecasting the production of 600 million AM-OLED units in 2015, but added that “1 billion are possible.”

One issue with AMOLEDs is their reflectivity in bright sunlight, making the screens harder to see.

Super AMOLED displays have integrated touch screens and are brighter, clearer and less reflective than normal AM-OLEDs, giving them greater visibility in sunlight. Super AMOLEDs are featured in three new Samsung smart phones hitting markets mostly outside the US this year: the Wave, the Galaxy S and the Galaxy Beam, which also includes a Texas Instruments picoprojector.

AMOLED TVs from a Gen 8 fab are on the horizon, Kim said, predicting that “AMOLEDs will be mainstream for premium TVs by 2015.” One Gen 8 substrate can produce 18 32-in. panels.

In the future, AMOLEDs also could be used to create transparent displays. LG and Samsung demonstrated such prototypes during Display Week.

Into the future

So what innovations are on the horizon? Displays that can “see,” said Microsoft’s Bathiche. “Touch is just scratching the surface.”

Two years ago, Microsoft introduced its Surface table, which resembles a coffee table-size horizontal iPad and can be found mostly in restaurants, hotels and other public venues. The technology is “a membrane that blends virtual and physical worlds,” Bathiche said.

In his Display Week keynote address, Bathiche showed a video of Microsoft’s vision of the future, which included wall-size transparent displays that “make you feel like you’re reaching into the screen – that this person across the world is literally sitting beside you.”

The company is developing the technology to be bidirectional, which will allow it to recognize gestures up off the table, to re-create objects stacked up off the surface of the table and to reproduce gestures such as folding, tearing and stretching in a virtual image as though it were a real one.

“We will take virtual objects and make them feel real.”