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The Great Future of LED TV(3)–Thinner、Better Picture Quality and More Energy Saving


2008-10-06 Optical Semiconductors editor

Observing the strategies of those main LED TV manufacturers one can find that all LED TVs are made with 40-inch or larger panels. This is because the price of the U-shape CCFL for 32-inch panels is very cheap, which is half or two-third lower than the price of the LED back-light. Therefore the manufacturer is more willing to  adopt LED back-light in the big-screen TV, in this way they can aim at the top layer of consumers .

Regarding to the back-lighting technology, it’s separated into 「Direct Type」 and 「Edge Type」. At present most LED TV adopts the Direct Type technology, which puts the back-light directly in the back of the panel, and uses the diffuser to diffuse and equalize the light.

The Edge Type technology puts LEDs around the panel and uses  transmitters to project the light equally on the back of the panel. The Edge Type can reduce the number of LEDs while compared to the Direct Type. For example, making a 46-inch LED TV with the Direct Type technology, you need 1100 to 1300 pieces of LED, but with the Edge Type you only need 400 to 600 pieces.

Regarding to LED technology, most manufacturers formed their LED back-light with red, green, and blue LEDs. They combine the Direct Type technology with the Local Dimming technology to turn bright or dark the individual parts of the picture, so as to make the contrast more conspicuous. Besides, some manufacturers use RG Phosphor and blue LED to produce white light, in this way they can reduce the number of LEDs and bring the costs down. White light also has better result than the combination of blue LED and YAG.



In the future, the main stream of LED TV will go in two direction, either high-definition or ultra-thin. At the moment most LED TVs have walked in the first direction. With RGB LED and the combination of Local Dimming and Direct Type, the contrast ratio is improved. Many producers claim that the dynamic contrast ratio of their LED TV can be as high as 1000000:1 and even higher. The 46-inch LED TV put an emphasis on the quality of picture and contrast, and it’s priced very high to aim at the top layer of consumers.

Another direction is ultra-thin, which possibly combines RG Phosphor and blue LED, and adopts the Edge Type back-lighting technology. In this way there would be no CCFL or LED in the back of the panel, thus the TV can be made ultra-thin, and the costs can be reduced as well because the Edge Type requires less LEDs. But the Edge Type can not adjust the darkness or brightness in some areas, so it would have to sacrifice the contrast ratio and the degree of saturation.

As a result, in the future main manufacturers may produce Edge Type LED TV with  46-inch or smaller panels, which will be the main stream. In the contrast, they will also produce Direct Type LED TV as a high-end model to target a different market.

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