Monday, November 26, 2007

Flat panel display

Today Flat panel displays are widely used. They cover a growing number of technologies that enable video displays that are lighter and much thinner compared to the traditional television and video displays which mostly use cathode ray tubes. They are usually less than 4 inches (100 mm) thick. And are divided into two general categories, viz. Volatile or Static.

Volatile

Volatile displays require constant power output to refresh the image on screen many times a second. The image appears steady because the images are refreshed more often than the human eye can perceive.

Examples of Volatile Displays:

• DLP (Digital Light Processing)
• Plasma displays
• Liquid crystal displays (LCDs)
• Organic light-emitting diode displays (OLEDs)
• Light-emitting diode display (LED)
• Electroluminescent displays (ELDs)
• Surface-conduction electron-emitter displays (SEDs)
• Field emission displays (FEDs)
• Nano-emissive display (NEDs)

Only the first five of these displays are commercially available today, though OLED displays are beginning deployment only in small sizes (mainly in cellular telephones).

Static

Static flat panel displays rely on materials whose color states are bistable. This means that the image they hold requires no energy to maintain, but instead requires energy to change. This results in a much more energy efficient display, but with a tendency towards slow refresh rates which are undesirable in an interactive display.

Examples of Static displays are:

• electrophoretic displays (e.g. E Ink's electrophoretic imaging film)
• bichromal ball displays (e.g. Xerox's Gyricon)
• Interferometric Modulator displays (e.g. Qualcomm's iMod, a MEMS display.)
• Cholesteric displays (e.g. MagInk, Kent Displays)
• Bistable nematic liquid crystal displays (e.g. ZBD).

Bistable flat panel displays are beginning deployment in limited applications (Cholesteric displays, manufactured by Magink, in outdoor advertising; electrophoretic displays in e-book products from Sony and iRex; and bistable liquid crystal displays from ZBD in store shelf labels).

Flat panel displays balance their smaller footprint and trendy modern look with high production costs and in many cases inferior images compared with traditional CRTs. In many applications, specifically modern portable devices such as laptops, cellular phones, and digital cameras, whatever disadvantages are overcome by the portability requirements.

No comments: