There are three main kinds of television on sale today: LCD, LED and plasma. Here’s a handy guide to how the three types of TV work:
The most common type of TV is the LCD set. This operates by means of fluorescent liquid crystals, which modulate the amount of light allowed through from the backlight behind the screen. Dark colours and blacks are created simply by blocking out the light completely – or, at least, as much as is possible. The light is seen to best effect when viewed from directly in front of the screen, so viewers at an acute angle can suffer reduced picture quality.
Because of their relatively simple technology, LCD televisions are generally cheaper than other TVs of equivalent size, have a lower power consumption than plasma TVs and are lighter, too. However, LCD TVs cannot display true blacks, instead approximating to them with dark shades of grey. They are also not available with the very large screen sizes that characterise plasma sets.
These work in a very similar way to LCD sets and may be considered a refinement of LCD technology. The major difference is in the backlighting: on a conventional LCD set, this is provided by traditional lamps. However, as their name implies, LED TVs accomplish this with a dense matrix of hundreds of minuscule LED lamps placed either behind the screen or around the edge. This gives more even illumination and therefore improves control over colour fidelity.
Because there are no large lamps behind the screen, LED TVs can be much slimmer and lighter than LCD models. They are also much more economical to run than the other types of television, since LEDs consume very little power. However, LED TVs are still considerably more expensive to purchase than an LCD set and still suffer the viewing angle problems of LCD TVs.
In plasma TVs, two glass panels sandwich a vast array of tiny cells, each of which contains a very small amount of mercury and a mix of noble gases such as neon and argon. When an electrical charge is passed across a cell, the mercury is vaporised and its energy transferred into photons of ultraviolet light. These collide with the phosphorescent coating on the inside of each cell, producing visible light; the precise colour emitted depends on the precise voltage of the electrical charge.
Because they can display very accurate colours and true blacks, plasma TVs offer the best picture quality under most conditions. However, plasma TVs may need careful handling early in their lives, in order to avoid burn-in on their screens. They are also much heavier than LCD sets because of the two glass panels, while their power consumption is often more than twice as high as that for an LCD TV of equivalent screen size.
Alastair, a technology geek and blogger, provided this article for LG. To find out more about Internet Connected TV From LG come visit their website.