Types of HDTVs
There are several types of HDTVs available today:
This technology encloses a gas between two sheets of glass, and depending on how the gas is energized it emits ultraviolet of a certain energy, which in turn excites phosphors on the plasma TV screen to produce a visible light image. They produce a wonderful image with brilliant colors and high contrast. They are however bulkier than say LCDs or LEDs and also more fragile. They do not work well at altitudes greater than 6000 feet.
Flat Panel LCD TV
This technology is the same as your laptop screens and flat panel computer displays. Each individual pixel is displayed by the action of liquid crystals. These are extremely light weight and consume very little power. They have the potential problem of dead pixels and are difficult to view at wider viewing angles.
This is a variation on LCD technology that uses LEDs instead of fluorescent lighting as the backlight. These provide better viewing angles, brightness and contrast ratios than traditional LCD technology. They also don’t use any mercury and have a lesser environmental impact. However, it will likely take some time before they become as inexpensive and as common as LCD TVs. Perhaps around the same time as all programming becomes HDTV.
There are a few other technologies such as Digital Light Processing (DLP), some projection-based, as well as CRTs, but each of these, it appears, is becoming less and less popular. Look up the article "HDTV buying Guide: Wrapping things up" for a overall sum up.