Large-size LED backlight market to triple in 2007

In what it describes as a "conservative" outlook, market analyst DisplaySearch says that unit shipments of LED backlights for LCD televisions and PC monitors will reach nearly 3 million in 2007.

LED-based backlights for large-size LCDs are viewed as one of the key next-generation applications to drive sales of high-brightness emitters.

However, the market has been very slow to take off so far, and only 1 million LED backlight units for screens greater than 10 inches in size shipped in 2006, according to DisplaySearch s latest report. Since the backlight unit is the most costly component in an LCD panel, this still equated to a market value in the region of $50 million.

That slice of the sector represents only a tiny fraction (0.4 percent) of the total available market, with a remarkable 277 million large LCD screens selling last year.

But LED backlight shipments are now expected to increase rapidly, to 2.9 million in 2007 (0.9 percent of all large LCD backlights), 8 million in 2008 (2.1 percent) and 12 million in 2009 (2.8 percent). The 2009 figure ought to equate to a market value upwards of $300 million.

The Sony experience
According to DisplaySearch's Director of Display Technology Steve Jurichich, the key reason behind the relatively conservative forecast for LED backlight penetration is that there is still a great deal of uncertainty over the merits of the new technology when its cost to manufacturers of LCD TVs and monitors is taken into account.

"The Sony experience has made them much more conservative," Jurichich said, referring to the Japanese company's failed attempt to lure early-adopters to buy its very-high-end LED-backlit Qualia TVs in 2004. "Those sets were ahead of the curve , and with 450 individual LEDs required, they were also very expensive."

Since then, market penetration has been largely restricted to notebook and handheld PCs, where the advantages of LEDs are quite different.

LEDs are useful in mobile applications because they drain much less battery power than traditional cold-cathode fluorescent lamp (CCFL) backlights, significantly extending the operating time of a notebook PC when it is used on a long flight, for example.

Since 2005, notebook PC screens including Sony s 11-inch Vaio, Fujitsu-Siemens 10.6-inch handheld, and Toshiba s Libretto "“ the first notebook to feature an LED backlight "“ have enjoyed more success than the Qualia TV.

Phosphor and RGB applications
The different requirements of the PC monitor and LCD TV markets mean that different LED technologies suit the two applications best.

In the TV market, the quality of the colors generated on screen is highly important, which means that individual red, green and blue emitters are needed. But for notebook PCs, this is much less of an issue and phosphor-based white emitters deliver sufficient color quality.

This means that the initial uptake of LED backlights will continue to be very much focused on the PC notebook sector before TV makers start to deploy RGB backlights.

The key advantage for RGB LED backlights in TV applications is the color rendering compared with CCFLs, particularly for red images. This is because the red portion of light emitted by a CCFL has typically been weak when compared with the blue and green parts of its emission spectrum.

Jurichich warns that CCFL makers are not standing by idly, and that this technology is now being developed to improve the red color rendering. "They have raised the bar," he said.

Developers of LED backlights, which includes the LED makers Cree, Lumileds and Osram Opto Semiconductors, may therefore have to concentrate on other advantages of solid-state technology, for example the fact that LEDs do not require a large strike voltage to start up. This means that fewer capacitors are needed in the backlight unit, although using three independent light emitters does increase the complexity of the control circuitry.

Another advantage of RGB LEDs over CCFLs is that they can be switched very quickly and synchronized to deliver a high-quality image without the need for a color filter.

This could be a decisive factor in LEDs favor, because the color filter is the second most expensive part of an LCD TV (after the backlight itself), accounting for 19 percent of the component costs in a typical 40-inch screen. Though it may be five years before this technology is fully developed, says Jurichich, this advantage could ultimately be the one that sparks widespread market penetration for LEDs.

For now, though, the key requirement for LED and LED backlight manufacturers to focus on is an age-old one: improve the dollars-per-lumen ratio. For a 23-inch TV, a relatively modest improvement in LED efficacy to 60 lm/W would reduce the number of LEDs required in the backlight by around one-third from 309 to 234. At that point, the extra cost of the backlight would be much more acceptable to manufacturers and consumers alike, says Jurichich.

DisplaySearch s 832-slide TFT LCD Materials Report is available now. See the company s web site for details.