What is Flat panel display?
Flat panel display is a very thin display screen used in portable computers. Nearly all modern flat-panel displays use LCD technologies. Most LCD screens are backlit to make them easier to read in bright environments.
A flat display apparatus is smaller and lighter than the display apparatus having the cathode ray tube (CRT). Cathode ray tube (CRT) designs have been the predominant display technology for purposes such as home television and desktop computing applications.
CRTs have drawbacks such as excessive bulk and weight, fragility, power and voltage requirements, electromagnetic emissions, the need for implosion and X-ray protection, analog device characteristics, and an unsupported vacuum envelope that limits screen size.
Conventional cathode ray tube (CRT) displays are unsuitable for use in multimedia applications because of their large volume. To address the inherent drawbacks of CRTs, such as lack of portability, alternative flat panel display design technologies have been developed. These include liquid crystal display (LCD), plasma display panel (PDP), electroluminescent display (ELD), vacuum fluorescent display (VFD), and field emission display (FED). Of these, the liquid crystal display is widely used as a display for an information terminal.
Liquid crystal displays include two panels provided with two kinds of field-generating electrodes (e.g., a plurality of pixel electrodes and one large planar reference electrode) on their inner surfaces and a liquid crystal layer interposed between the panels.
Electroluminescent displays (ELDs) differ from LCDs in that they are not light filters. Instead, they create light from the excitation of phosphor dots using an electric field typically provided in the form of an applied AC voltage.
Thin film transistors (TFTs) are used as switching units to control the operations of pixels or as driving units to drive pixels in flat panel displays, such as, liquid crystal displays (LCDs) or organic or inorganic electro-luminescent (EL) displays. Among color display devices used for image display on a computer or television, a display device using a plasma display panel (PDP) has recently been drawing attention, as a large, thin, and light color display device.
A plasma display uses plasma generated by gas discharge, to display characters or images. Such a PDP is classified as a direct current (DC) type or an alternating current (AC) type according to the PDP’s discharge cell structure and the waveform of the driving voltage applied thereto. Vacuum fluorescent displays (VFDs) use cathodoluminescence, vacuum phosphors, and thermionic cathodes. Field emission displays (FEDs) are devices comprised of a front substrate and a rear substrate forming a vacuum chamber.
The FED uses a cold cathode as the source for emitting electrons, which are used to realize the display of images. With the advance of techniques for fabricating thin-film transistors, the flat panel displays (FPD) are widely applied in electronic products, such as PDAs, laptops, digital cameras, camcorders, cell phones, etc. due to advantages as portability, non-radiation and lower power consumption.
Flat panel displays can be divided into two general categories Volatile or Static.
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.
Static flat panel displays rely on materials whose color states are bi-stable. 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.