TOKYO Nichia Corp. has developed a white LED chip with 100-lumens/watt efficiency, with volume production expected this year. The move comes amid an intensifying race to boost the efficiency of white LEDs so the parts can compete against conventional lighting devices.
Nichia, a leading supplier of blue and white LED chips, showed prototypes of a pendant light and a spotlight using the white LED.
For white LEDs, efficiency must rise to between 70 and 100 lumens/W in order to compete with fluorescent lights. Indeed, 100 lumens/W is a milestone for white LED players. That level was not expected until 2008 to 2010.
High-output white LED chips are available, but they consume more power, lowering efficiency.
One approach is to realize the efficiency as a module or a lighting apparatus using multiple chips. In this case, each white LED chip does not have large luminous flux (lumens) output but needs low power dissipation to realize the high efficiency. Nichia developed a chip that delivers 6 lumens with an input of 20 mA at 3 V, achieving 100-lumens/W efficiency. No white LED chips have been developed with triple-digit efficiency, said a spokesman for Nichia.
The prototype pendant light employed 756 units of the white LED chip to deliver 4,536 lumens with a 45-W input. The spotlight consisted of 80 chips, delivering 480 lumens with 4.8-W input. As a lighting apparatus, each of them also had about 100-lumens/W efficiency.
Nichia intends to start sampling the 100-lumens/W chip in June and to start volume production by year's end. The first product will come in the form of a 5-mm-diameter lamp package.
Two years ago, Nichia had projected a 100 lumens/W white LED chip would reach the market in 2010. But in its development road map, shown March 8, the timetable was accelerated, setting the next target, 150 lumens/W, for 2007.
Nichia introduced the first white LED in 1996, with an efficiency of just 5 lumens/W. According to the road map, Nichia has been steadily improving performance, to 50 lumens/W in 2003, 70 lumens/W in 2004, 85 lumens/W last year and 100 lumens/W this year. The 85-lumens/W chip will hit the market around April, with the 100-lumens/W part to follow by the end of this year.
There wasn't a big technical jump, said Gen-inch Shinomiya, managing director in charge of the R&D engineering division at Nichia. "We improved our technology incrementally and steadily have reached this level. And I believe we can reach the level of 150-lumens/W efficiency in the same way," he said.
White LEDs generate white light by combining red, green and blue LEDs, or by using a blue LED and yellow phosphor. Nichia is pursuing the combination of a blue LED and yellow phosphor because of a perceived superiority in color rendering.
To this point, white LEDs are technically comparable to fluorescent lights. "The biggest bottleneck is cost," said Shinomiya. If simply compared in price, a white LED costs nearly 10 times more than a corresponding fluorescent. Considering LEDs' advantagesa low running cost and no need for additional circuitrythe cost is still several times higher than for conventional lamps.
In celebrating its 50th anniversary this year, Nichia expects total revenue of 195 billion ¥ (or $1.7 billion) for its fiscal year, which ends this month. The company claims to have the top share in three markets in the world: phosphor materials, materials for batteries and GaN-based LEDs. Despite its growth, the company said it does not plan to go public.
The company's mid-term business strategy calls for sales growth to about 300 billion ¥ ($2.6 billion) by 2010. Under the strategy, LED production is expected to double, to 10 billion units a year, by 2010. Nichia manufactured more than 5 billion units of GaN-based LEDs last year, and nearly 90 percent of them were white LEDs, said Noboru Tazaki, executive vice president of Nichia. Nichia estimates 13 billion to 15 billion units of GaN-based LEDs were produced globally last year; a large percentage of them were low-end products.
Sharp price erosion in LEDs, especially for backlight of LCD panels, dragged down Nichia's sales by about 5 percent from the year before. Both Nintendo DS and Sony PSP game gears use Nichia's white LED for the backlight.