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Cathode ray television sets are seeing their dominant position threatened by two increasingly popular technologies: plasma and LCD. Both offer excellent features in terms of picture quality and above all ease in adapting to any setting. In fact, they have solved one of the biggest problems faced by cathode ray TV sets: their large volume and bulkiness. Plasma screens and LCD have launched the concept of a picture within a frame. They can be hung anywhere, just like a painting, and are simple to move around.

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This technology dates from the 1960s when it began to be used in screens, or displays, of things like wristwatches and calculators. In the 1990s it spread widely as the technology was used in computer screens, and these days many TV manufacturers now offer models based on LCD. They include Loewe, Panasonic, Samsung, Sony and Sharp. LCD screens use a system of white back-lighting that is blocked and filtered with the help of polarizers and crystal molecules that are in a hybrid, solid-liquid condition known as an isotropic state. Each dot on the screen is an LCD cell that either does or does not let light through.

The pixels are arranged in the form of a fixed matrix, and shapes are represented as cells light up or turn off. This is achieved with a sweep that lights up each dot just once, but so fast the picture looks as if they were all lit at once. Color is achieved with three filters corresponding to the primary colors red, green and blue. From these, different combinations of intensity render every tone perceptible by the human eye.

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The problem with this technology is that it still does not allow for very large screens, and some models do not handle fast movement on the screen well. They also have light and viewing angle troubles. The pixel switching requires expensive transistors, so as the size of the screen increases so does the price. Now these sets cost about half a million pesetas.

The first research into plasma began in the 1970s, although the first prototype of a plasma screen did not come out until 1995. It was Sony that unveiled its Plasmatron, a low-light screen with a limited viewing angle. Still, it impressed people with its slimness and size. Three years later the first 42-inch models were presented in Europe. They cost about three million pesetas and had decent definition, but levels of lighting and contrast well below those offered by traditional cathode ray TV sets.

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Plasma screens have a sandwich-like structure. Between the two large sheets of glass that make up the screen are thousands of tiny cells containing a mix of xenon and neon. When electrical current passes through the cells, this blend of gases turns to plasma and generates ultraviolet energy. The walls of the cells are covered with red, green and blue phosphorous that is sensitive to ultraviolet rays and generates thousands of multicolored dots. Thus, when looking at a plasma screen what you are really seeing are millions of neon lights that blink on and off in an ordered fashion. When they come in contact with fluorescent material they turn red, green and blue and produce the television picture seen on the screen.

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These days there are plasma screens up to 90 inches, although the average size is 40. They are less than 10 cm thick, relatively light and the picture quality gets better with each new generation. The latest models of companies such as Dream Vision, Fujitsu, Grundig, JVC, LG, Loewe, Marantz, NEC, Panasonic, Philips, Pioneer, Samsung, Sanyo, Sony and Thomson feature uniform lighting from the centre to the edges of the screen and their contrast is more than acceptable. Still, it remains to be seen if this technology will be widely embraced by consumers. For this to happen, prices have to come down.

They currently average around two million pesetas. Manufacturing must be optimized because currently the process is extremely expensive.�� Companies like Fujitsu, a pioneer in this technology and its main manufacturer worldwide, has undertaken the task. It has unveiled the High Definition Series, a line of 32- and 37- inch plasma screen TVs that feature two new technologies: ALIS (Alternative Lighting of Surface) which doubles resolution using the same number of electrodes as a conventional screen, and TRS (Technology of Reciprocal Sustainer), developed along with Hitachi and aimed at lowering the production cost. LG estimates that in 2005, 11 of every 100 television-buyers will opt for plasma. Major consumer electronics firms are counting on them to take hold, and those firms which initially did not offer any plasma models (Samsung, for instance) are doing so this year. It's a sign they don't want to miss out as times and tastes change.

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