Flat Panel Displays - Beyond Plasma

By Author: Steve Faber
Total Articles: 6
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The term set-top box will become something of a misnomer in the near future, as most displays will become too thin to allow a box to placed on top of them. As the price of plasma & LCD displays has plummeted and their image quality has improved, they are popping up in homes everywhere.

Although they are the darlings of the media and the generic for flat panel display in the minds of many, plasmas are about to be in a serious fight with other technologies for the flat panel crown.

LCD displays, seen on the desktop for years as computer monitors, and commonplace in smaller flat panel TVs, are finally increasing in size to the point they are becoming a rival to plasmas in the 42" - 50 size range. Picture quality is similar to plasmas; however LCDs are immune to the burn-in that can affect plasma displays. This burn-in occurs when plasma units are used to display static images such as video game screens and stock or sports tickers.

Plasmas generally have an edge in the ability to produce deeper blacks and more saturated colors than LCDs. Plasmas are also better at producing full motion video ...
... than LCDs because of the response time of the LCD panels, although this difference is disappearing.

LCD TVs are a bit more expensive than plasmas at 42" and larger sizes, but they should last a while longer. Plasma displays should last 20,000 - 25,000 hours and LCDs should give 30,000+ hours of useful life. However, the latest generation of plasma displays from NEC is claimed to have a 60,000 hour life. If that is an industry trend, the traditional lifespan advantage held by LCDs may soon disappear.

Currently Sony has a 42", NEC a 40", Sharp a 45", and Samsung a 40" LCD TV or display. Samsung also has the big one, a 46" that started shipping in early September of 2004. The Samsung 46" was the first consumer LCD video display to have a 1080 line native resolution. This allows it to display 1080p native when that format arrives for HDTV.

Other technologies are on the horizon as well. One that has shown great promise is OLED, for Organic Light Emitting Diode. Developed by Kodak and Pioneer, this technology has been used for a few years in car stereo and cell phone displays. It's just about ready for prime time. Philips has shown a 13" unit, Samsung a 17", and Seiko-Epson has shown a 40" prototype.

OLED's advantages are many. It actually emits it's own light, so it requires no backlight and has better contrast than a traditional LCD. OLED displays have a wide viewing angle like a plasma display. Power usage is very low, less than 1/2 that of a traditional LCD display. At around 2mm deep, OLEDs are much thinner than either a plasma or LCD.

They have a refresh rate about 1,000 times faster than a traditional LCD, so they will be far superior for video applications. They have fewer parts than LCD or plasma and can be manufactured using a novel ink jet printing process. This promises to keep prices low as the technology is implemented. It is expected to see sub 20" displays in stores by 2006 with larger units following one to two years later.

Other promising display technologies on the horizon include SED (Surface-conduction Electron-emitter Display) and carbon Nanotube. SED was developed by Canon, who began research into the technology in 1986. SED is basically the same principle as CRT, however there are important differences. The most important from a consumer standpoint is thickness. An SED display is only an inch or two thick, depending upon screen size.

The basic construction is two glass plates separated by a vacuum. One of the plates is coated with phosphors the other is mounted with electron emitters. Electrons are ejected when a voltage of about 16 to 18 V is applied to the emitters. These electrons are then accelerated by a higher voltage into a beam similar to that in a CRT display.

The visual advantages of SEDs are as for CRT displays, great color, deep black levels and quick motion response. These advantages, combined with the slim form factor, low cost and small power requirement should make for a real winner.

A unit shown by Toshiba at a Japanese trade show in April of 2005 even had it's contrast ratio up to an incredible 100,000 to 1 by significantly reducing black luminance. Even if the specs were a bit inflated this would still amount to a fantastic contrast ratio, on the order of 5 times that of a traditional CRT. Toshiba has indicated they will move to this technology for all displays over 40 by 2006.

One fly in the SED ointment however. On April 21st, 2005 US firm Nano-Proprietary has filed a suit against Canon in the U.S. District Court of the Western District of Texas, alleging that the surface (SED) televisions that Canon plans to release violates a licensing agreement signed 5 years ago between the Japanese giant and Nano-Proprietary.

The pace of change in the home theater and entertainment display market has just kept accelerating. There are some promising technologies around the corner that will allow, as usual, higher performance, lower cost and more compact form factors. As prices for advanced technologies plunge and technology improves, it will make it even easier for the average person to have a fantastic media system almost anywhere in their home.
About the Author Steve has 15 yrs in electronics. He is a CEDIA certified designer with ISF and THX certificates. Experience includes: installer and programmer; system designer; business unit director for an a/v importer; sales rep for a CE distributor; and principal of a $1.5M+ CEDIA firm. He's now senior sales engineer for Digital Cinema Design in Redmond, WA. See him at The Home Theater and Automation Guide