The current status of LED backlight technology

After the large-scale application of LED backlight in notebook computers (NB) larger than 10 inches, the market began to speculate when LED TVs would be available in large quantities. LEDinside pointed out that since LED will make the TV picture quality more contrasting and the models thinner and lighter, it is estimated that LED TVs will develop in the future in the direction of high picture quality and ultra-thinness. However, since more than 1,000 LEDs are used for backlighting, both uniformity and reliability are problems, resulting in the current high cost of LED TVs. In the trade-off between price and ultra-thinness, it is expected that consumers will still give priority to price. It is expected that the global LED TV penetration rate in manufacturers' shipments will still be less than 1% this year, and the shipment penetration rate will not exceed 10% until 2012.

At present, LED backlight technology can be divided into two types: direct type and edge type. Among them, direct type backlight technology is more widely used at present, which means placing the backlight source directly behind the panel and using a diffusion plate to make the light source uniform. Edge type technology places LED modules around the panel and uses a light guide plate to evenly project the light source to the back of the panel.

Compared with the two technologies, the edge-lit type can save more LED particles. Taking a 46-inch panel as an example, the direct-lit type uses about 1100~1300 LED particles, while the edge-lit type only uses about 400~600. Since the direct-lit type uses a large number of LED particles, whether it is more energy-saving depends on the manufacturer's design capabilities. The edge-lit type has fewer CCFLs and LEDs placed behind the panel, so the overall design can be very light and thin. However, since it is difficult to adjust the brightness of some areas with the edge-lit type, the contrast and color saturation of the picture will be sacrificed.

As for LED technology, most of the LED backlight modules currently produced by various manufacturers are assembled with three-color LEDs of R, G, and B, and use direct-type technology with backlight local dimming technology to brighten or dim the picture in independent small blocks, making the picture contrast more obvious. Many TV companies claim that their dynamic contrast can reach up to 1 million to 1, or even higher.

In addition, some manufacturers have switched to using red and green phosphors (RG Phosphor) plus blue LEDs to stimulate white light. This not only saves the number of LEDs used to reduce costs, but the white light it stimulates is also better than the effect of blue LEDs plus yellow phosphors (YAG).

In summary, LEDinside said that in the future, the mainstream of LED TV will continue to develop in two directions: high image quality and ultra-thinness. However, when more than 1,000 LEDs are used as backlight sources, uniformity and reliability are both big problems, which makes LED TVs still face the problem of high costs. Therefore, although there are already TV manufacturers that have equipped LED backlight modules with high-end models with a screen size of more than 46 inches, emphasizing picture quality and contrast, they are all sold at very high prices, mainly targeting top consumers.

According to Witsview's research on the North American TV market, there is still a big gap between the retail prices of LED TVs and traditional LCD TVs. Comparing the prices of 40-inch and 46-inch LED TVs with general Full HD LCD TVs, although the price difference has narrowed compared to when they were first launched, the retail price gap between the two specifications is still as high as more than 30%, and this is only based on the old models in 2007. Since new models of LED TVs will be launched in 2008, the prices of old models of LED TVs are falling rapidly recently. If the prices of new models to be launched at the end of 2008 are taken into consideration, the price gap between LED TVs and traditional LCD TVs will be even greater.

On the other hand, LED TVs pursue high image quality and ultra-thinness. LEDinside points out that if consumers prefer high-contrast images, there are actually plasma TVs (PDP TVs) available, and it is not necessary to buy LED TVs. Although the thin and light appearance is attractive, the TV at home does not need to be moved frequently. For ordinary consumers, low prices may still be prioritized over thin and light appearance.

Overall, LEDinside believes that LED TVs are still products that only technology fanatics and top-tier consumers can accept. It is estimated that in 2008, LED TVs still accounted for less than 1% of global TV shipments. After 2010, when LED backlight technology matures and costs drop significantly, the penetration rate of LED TVs will gradually rise. It is estimated that the penetration rate of LED TVs will be close to 5% in 2010, and is expected to increase to 7%-8% in 2011, and will exceed 10% in 2012.