Friday, November 09, 2007
It's very understandable and certainly no secret that the vast majority of people who have seen HDTV love it. The wide screen, high sound quality, and level of detail in the picture are just fascinating. Equally fascinating in many ways is the technology that goes into creating a high definition television picture.
Plasma screen displays are a great example of that. At its simplest, a plasma screen is made up of thousands of tiny fluorescent lights and each one of those lights is a pixel that makes up part of the picture. The color and intensity with which a pixel glows is determined by the amount of current and the voltage of the current that's sent through it at any given time. This allows a plasma screen to display a wide variety of colors or no color at all for incredibly high contrast ratios resulting in incredibly deep blacks that LCD display technology can't achieve. In addition, the individual pixels of a plasmas screen display can change color extremely rapidly, so there's none of the blurring which also plagues LCD technology.
Despite all of these benefits, Plasma screens have a number of disadvantages. The most pervasively annoying and most quickly noticed is the tendency of a plasma screen to produce a loud buzzing sound when functioning at high elevations, but unless you happen to live more than six thousand feet above sea level this won't be a concern. A bigger problem for most people is that plasma screens just aren't very bright, and to make matters worse, they tend to fade in brightness over time. This makes them a much better choice for darker basement rec rooms than bright and airy living rooms. In addition, it's one of the worst technologies in the market from the standpoint of energy efficiency.
LCD screens are another very popular type of HDTV display technology. Liquid Crystal Displays as this technology is also known by is based on the ability of certain types of crystals to change shape- and therefore change how they filter light- when subjected to different kinds of electrical current. In an LCD screen, a sheet of these crystals is sandwiched between some kind of back lighting- fluorescents are most common, but some newer screen derive longer life and greater efficiency by using LED technologies. LCD screens have the advantages of having long lifespans, being good for a variety of lighting conditions, and being relatively energy efficient.
As already mentioned, LCD screens have the disadvantages of not displaying very deep blacks (it's difficult for the crystals to block out light), and blurring. While these are very real disadvantages, newer LCD screens are much better about it than the older ones were, and the technology is getting better all the time.
While it's strictly a projection technology, DLP or Digital Light Processing, has a lot of promise. It's good for a variety of light levels, it doesn't create blurring, and though it can be a bit of an energy hog, DLP will produce some of the cheapest HDTV screens for their size.
There are also plenty of other new TV technologies just visible on the horizon like Laser TV and holographic TV, but it will be a while before we can expect to get out hands on them.