>LED TV TechnologyFebruary 12, 2011 at 12:06 am | Posted in Article, computer and technology | Leave a comment
>LED stands for Light-Emitting Diode and contrary to what a lot of people think, it is not a new TV technology. It is simply another way to light the LCD – Liquid Crystal Display. A liquid crystal display is a glass that works by controlling the capacity of its segments (pixels) by varying the electrical signal. Each segment (pixel) acts as a shutter to control the amount of light being passed through. The fundamental difference between an LCD TV technology and an LED TV technology is the source of light that pass through these pixels.
LCD TV Technology
On LCD TV displays, fluorescent lights are used to back-light screens. LCD TVs use a Cold-Cathode Flourescent Lamp (CCFL), which are lamps that can, and are used by some people to light their homes. To back-light a television, a series of these lights are horizontally laid across the back of the television. The light is distributed evenly onto the glass panel by a plastic sheet placed in front of the light and for the most part, produces a clear image on your screen. However, creating a true black picture is often difficult with the LCD technology. This is because to darken a screen the light source must be blocked out, and with LCD, the light is continuously on. Manufacturers get through this by blocking out the light source with a screen is darkened, but with most televisions, the light bleeds through, hence never allows for a true-black image.
LED TV Technology
LED TV technology on the other hand use tubes (LEDs) which are smaller than CCFL tube to produce the light. There are two styles of LED lighting – edge and direct mount.
Edge lighting arranges the LEDs along the edge of the television panel. As a result of the tubes being mounted on the edge of the television, the television can be created much thinner. The ultra thin TV sets displayed in shops use this type of lighting technology. LED light is channelled behind the television glass, with the light being spread evenly by guides.
Direct lit LEDs are tubes placed behind the television glass. The amount of LEDs placed depends on the size of the television with as many as 1500 LEDS. A single LED can be responsible for lighting up 1400 pixels on your screen. The main advantage of direct lit LEDs is that if an area of your screen is dark, the LEDs can be turned off thereby increasing the contrast. This is also known as local dimming, which LCDs cannot perform.
There are two types of direct lit LEDs – White and RGB (red, green, blue). White LEDs are similar to CCFLs in that they produce white light. RGB LEDs use the three colours, which makes the television capable of a broader range colour.
The debate of which is better out of LCD and LED TV technology continues, and the debate on what type of LED tube is best is an even bigger debate. Opinion, in this case, very much rules!