OLED may take over LCD, but not yet

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You may not have heard of OLED, but the Japanese government has. And on July 9, 2008, it announced that it will support Sony, Sharp and other Japanese manufacturers in a joint development to further develop the screen technology. The overall goal is to increase the lifespan and efficiency of the screens and to create of an affordable 40-inch OLED display panel, which the companies hope to develop by 2015.

The rivals will work together on development, although a Sony spokesman said it will keep the advanced technologies in-house.

OLED (organic light emitting diode) display technology has LCD beat in many categories, including power consumption and color. Development of the tech is still in its infancy, meaning lifespan issues, screen size and particularly price points still prevent it from being a worthwhile option for digital signage. But it has potential.
Ron Mertens, editor of oled-info.com, is optimistic that large-format OLEDs, like those used in digital signage applications, will be produced in the future.

“I’ve been watching OLEDs since 1998 and the technology has always been ‘2-3 years away,'” Mertens said. “Now so many companies like Sony, Samsung, Toshiba, LG and Matsushita are betting on OLEDs that perhaps now it is for real.”

At the moment, OLED displays are only available in small screen sizes and are steep in price. Last year, Sony introduced an 11-inch monitor at the Consumer Electronics Show (CES), the XEL-1, which went on the market for around $2,500. At the Display 2008 show in Tokyo, Sony demonstrated two models of OLED screens – one of which was an 11-inch monitor that is only .3mm thick, one-tenth the thickness of the XEL-1.

A Samsung OLED monitor. Courtesy of Samsung.
Samsung unveiled a 31-inch OLED TV at the January 2008 CES and representatives from Samsung’s Display Interface division said the company is promising much larger screens to come. Representatives from both Sony and Samsung representatives declined to comment on any immediate plans for screens designed for digital signage applications.

A leg up on LCD

OLEDs’ thinness makes the screens very lightweight and is what will most likely attract digital signage users to the screens in the future. It is the working principle behind the technology that allows the screens to be so thin.

According to Eastman Kodak, creators of the first OLED, the technology is created by stacking thin films with positively and negatively charged particles in between. When electricity is applied, it stimulates the particles causing radiation, which causes light. OLED gets the term “organic” because the diodes are made from carbon and hydrogen.
OLEDs provide several advantages in comparison to LCD:

• Thinness. Since OLEDs emit light, no backlight is required, meaning OLED panels can be produced much thinner than any LCD or plasma screen.

• Less power consumption. Not having a large backlight also means that OLEDs consume less power, which may be a key selling point in the future as the digital signage industry looks to green initiatives.

• More vibrant color. Since OLEDs produce their own light, the colors produced by the screens appear more vibrant and un-shifted. Mertens said that emitting direct light means that the viewing angle can be 90 degrees from normal, something that could be very beneficial for digital signage.

• Better picture. LCDs cannot show true blacks because the backlight is always on when the screen is powered on, creating filtered white light that can make blacks appear grey-ish. In the case of OLEDs, the diodes turn completely off and therefore show no light at all, creating a true black. This is the reason that the Sony 11-inch XEL-1 can boast a contrast ratio of 1,000,000:1.  

• Response time. The response time for OLEDs has also shown to be considerably faster than LCDs, which is about four to eight milliseconds. Mertens said an OLED screen can have less than a 0.01ms response time.

Organics increase vulnerability

OLED technology may sound promising for the future of the digital signage industry, but there is a reason it’s limited to several 11-inch monitors. Mertens says that since the elements are organic, degradation of OLED materials has limited their use. Specifically, blue OLEDs have a lifespan of about 14,000 hours, which is about five years with eight hours a day of usage. With many digital signage applications lighting up screens 24/7, this would mean only a few years of use.

Also, the intrusion of water and other elements into OLED displays can deteriorate and or destroy the organic materials. Screens housed in proper enclosures will be fine, but the lack of sealing technology may hinder the production of flexible and spreadable OLEDs.
For now, the immediate future of OLEDs is small – in screen size, that is. According to oled-info.com, which maintains a list of products available with OLED screens, an overwhelming majority of OLED screens are currently embedded in mobile phones and mp3 players. Those screens range from two to four inches and are becoming more popular due to their high brightness and low power consumption.

The future

OLED technology may open the door for some very unique digital signage applications that are being experimented with. Prototypes for flexible and roll-able displays have been developed by companies like GE, but have yet to be put into mass production. In 2007, Sony released a 2.5-inch flexible OLED display that could be bent with the hand while still running video.

In an even more extreme application, possibly revolutionary for digital signage, two Japanese companies are working on a solar powered OLED screen, TechRadar UK reported in May 2008. Mitsubishi Chemical announced they were working on a paste that could be spread onto a surface to create an OLED screen. Sumitomo Chemical, one of the companies involved in the current Japanese joint venture, created a similar paste that could be enough to power the screen when exposed to light, therefore eliminating the need for power sockets and plugs.

Brad Gleeson, vice president of business development for Planar, thinks that OLED may serve as an alternative to current screen technology in the future.

“Plasma and LCD is definitely not the last panel technology we’ll ever have,” he said.

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Through out my years, Sony has been a passion of mine.

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