High-Definition Plasma Screens
Plasma, short for (PDP or Plasma Display Panel) is one of the two leading display technologies on which high-definition images are likely to be delivered for the foreseeable future.
- Plasma Display Technology
- LCD vs. Plasma Note
- Advantages of Plasma Displays
- Disadvantages of Plasma Displays
In simple terms a plasma display is made up of two glass sheets in between which are sandwiched small capsules of gas that emit light when an electrical charge is applied to them, so forming image you see.
An Exploded View of a Single Plasma Pixel
In reality the technology is a little more complex but no so much so as to make it incomprehensible. A plasma display is made up of a matrix (or grid) or one or more millions of pixels (picture elements) each made up of three sub-pixels, one for each of the primary colours; red, green and blue.
Each of these sub pixels is a small chamber which contains a mixture of inert xenon and neon gasses and whose sides are coated with appropriately coloured phosphorus. A matrix of electrodes criss-crosses the display addressing each such pixel individually so that each can be heated, turning the gasses inside in to plasma. This plasma emits ultraviolet radiation which in turn excites the sub-pixels' phosphorous coatings so that they give of light of the desired primary colour.
Differing intensities of each primary colour are produced by pulsing each sub-pixel on and off during each video frame, and the overall pixel's colour and brightness is produced by the combined relative intensities of each of its sub-pixel's primary colours.
The real 'truth' about LCDs vs. Plasma is that neither technology is inherently or necessary better than the other. LCD and plasma technologies are constantly converging to the point of being equal in terms of an everyday viewing experience. The advice below represents a general, current overview of the pros and cons of each display type, but there simply is no substitute to taking the time to experience both technologies for yourself before making a purchasing decision.
Plasma screens generally have better colour reproduction than LCDs, meaning that they are able produce richer range of hues (gradations of colour) and good saturation (intensity of a particular hue). That said however this is the general case for plasmas, some will be worse than others, and the best LCDs are starting to rival plasmas in this area.
Similarly as a rule plasmas tend to have feature better contrast ratios (the difference between the lightest whites and darkest blacks the display is able to produce). Plasma's brightness (and therefore contrast) is affected by the amount of the screen that is light or white, so brightness of fully white screen may be less than if a quarter of the screen where white. Plasmas also tend to perform better in low ambient light where reflections from the glass in the display are reduced. Similarly plasmas as plasmas emit light rather than blocking a backlight (as an LCD does) they generally produced darker backs and hence better contrast.
Plasmas are thought to portray motion well and while this certainly the case for good displays, not all are created equal and poor examples can produce a jerky picture during pans.
Historically plasmas have been available in larger sizes than LCDs however at present larger (than 42inch) plasma and LCDs are beginning to become available.
Plasmas have a reputation for being susceptible to screen-burn whereby having displayed the same static image for long periods of time the image would begin to be retained/remembered by the screen. This problems is less of an issue with modern displays and the problem itself is a unlikely scenario for the average conusemer.
Plasma displays as a rule consume more power and generate more heat than LCDs as by-product of the way the image is produced. A plasma display will usually require more power than CRT screen, however this is often due to the increased size of a typical plasma display.