LCD, Plasma or LED Television it's your choice.

What are the technologies that lie behind the TVs that we see on sale in the high street stores today and what are the differences. The common categories of televisions that we current see for sale are LCD, Plasma and LED TVs.

LCD is an abbreviation for Liquid Crystal Display. This type of display is made up of a matrix of liquid crystal pixels. Each pixel is divided in to the three primary colours red, blue and green. When a variable electrical current is passed through the individual pixels they are made to produce one of the colours. An LCD panel is lit by fluorescent lamps in either side or backlit configurations, and when this light passes through the individual cells or pixels the colours which make up the on-screen image are displayed.

There are many advantages and a few debatable disadvantages to be had with full HD LCD TVs. The advantages are as follows. Firstly they are lightweight when compared to the alternative of plasma TVs. They can be manufactured in a large range of sizes. They have high picture brightness and do not suffer screen burn (this was formerly a disadvantage with plasma TVs as discussed below) and they use less power than plasmas also. The big advantage of LCDs are with price, because of the cheaper production costs that is inherent with LCD technology and because of their popularity, the mass production of LCDs has resulted in them becoming the best value option in high definition viewing.

If there are any disadvantages of LCDs it is that they are not as capable at reproducing dark or black on screen objects. This is a characteristic that has been improved by innovations such as locally dimmable backlights. Also formerly with early LCDs they were said to be less effective at displaying rapid moving images (so that blurring of images on screed is seen). But again this has been greatly improved with high refresh rates and response times of modern TVs virtually eliminating these former deficiencies.

The next choice when it comes to purchasing a high definition TV is the full HD Plasma TV. Plasma televisions are considered to be situated at the higher end of the market because of the superior picture that is produced, the screen sizes are larger and because of both these factors the price is considerably higher. In the early days of HD TV both these factors were more applicable than they are today as the quality gap between LCD and plasma TVs has reduced.

The fundamental difference with Plasma displays is that the screen is made up of a matrix of minute gas filled cells. Each cell is subdivided and coated with different phosphors so that when an electrical current is passed through it the gas is heated and light is produced. Again the inherent properties of producing an image using plasma technologies has advantages and a few disadvantages.

The benefits of plasma are that it produces more life-like images with better colour reproduction, better contrast ratios (producing darker blacks), they are very good at displaying rapid movement without blurring and finally they can be manufactured for very large screen sizes.

If there are disadvantages to be had, they include price and weight of television. These factors are debateable as the price can be justified because of the benefits that come with plasma TVs and fact that they tend to be larger screen sizes, you are paying for what you get. A ‘former’ downside for plasmas was the issue ofscreen burn but this not really an issue with modern sets.

Another technology that you might have seen used in relation to high definition televisions is the LED TV. This is not strictly speaking in a category of its own, this is because an LED television is still basically an LCD TV with one difference - being that it uses LEDs to provide the back or sidelight for the LCD panel.

Formerly in LCD TVs and displays fluorescent lighting was used. LEDs are replacing the fluorescent lamps because they have some advantages over them. These are that LED produces ‘whiter’ light which improve the colours produced, they can produce brighter light and can be locally dimmed to reproduce better blacks. Also LEDs are smaller allowing for the production of thinner TVs and LEDs are also more energy efficient using as much as 50% less power than fluorescent lit LCDs and plasmas televisions.