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Plasma HD TV - What is it?

You can use Best TV Deals to view the HD ready TV ranges of top US brands including; Hitachi, Panasonic, Philips, Pioneer, Samsung and Sony. Use the sections above to compare prices for Plasma HD Tv's.

Plasma HDTV

A plasma display panel (PDP) is a type of flat panel display now commonly used for large TV displays (typically above 37"). Many tiny cells located between two panels of glass hold an inert mixture of noble gases (neon and xenon). The gas in the cells is electrically turned into a Plasma which then excites phosphors to emit light. It is often used in the home environment and is becoming increasingly popular in modern cultures.

Contrast ratio claims

Contrast ratio is the difference between the brightest and darkest parts of an image, measured in discrete steps, at any given moment. Generally, the higher the contrast ratio, the more realistic the image is. Contrast ratios for Plasma displays are often advertised as high as 10,000:1. On the surface, this is a significant advantage of plasma over other display technologies. Although there are no industry-wide guidelines for reporting contrast ratio, most manufacturers follow either the ANSI standard or perform a full-on-full-off test. The ANSI standard uses a checkered test pattern whereby the darkest blacks and the lightest whites are simultaneously measured, yielding the most accurate "real-world" ratings. In contrast, a full-on-full-off test measures the ratio using a pure black screen and a pure white screen, which gives higher values but does not represent a typical viewing scenario. Manufacturers can further artificially improve the reported contrast ratio by increasing the contrast and brightness settings to achieve the highest test values. However, a contrast ratio generated by this method is misleading, as content would be essentially unwatchable at such settings.

The underlying technology of Plasma displays allows for a high contrast ratio. Similar to CRTs, plasmas can achieve nearly true black because a cell/pixel can be switched off completely. This contrasts with LCD technology, where black pixels generated by a light polarization method are unable to completely block the underlying backlight. However, one shortcoming with plasma technology is that running a display at maximum brightness will significantly reduce the panel's lifespan. For this reason, many owners leave the brightness settings well below maximum, which typically still results in a brighter screen than CRT displays.

Screen burn-in

With phosphor-based electronic displays (including cathode-ray and Plasma displays), the prolonged display of a menu bar or other graphical elements over time can create a permanent ghost-like image of these objects. This is due to the fact that the phosphor compounds which emit the light lose their luminosity with use. As a result, when certain areas of the display are used more frequently than others, over time the lower luminosity areas become visible to the naked eye and the result is called burn-in.While a ghost image is the most noticeable effect, a more common result is that the image quality will continuously and gradually decline as luminosity variations develop over time, resulting in a "muddy" looking picture image.

Plasma displays also exhibit another image retention issue which is sometimes confused with burn-in damage. In this mode, when a group of pixels are run at high brightness (when displaying white, for example) for an extended period of time, a charge build-up in the pixel structure occurs and a ghost image can be seen. However, unlike burn-in, this charge build-up is transient and self corrects after the display has been powered off for a long enough period of time, or after running random broadcast TV type content.