LED makers broaden their spectrum

16 May 2003

Toshiba and Lumileds unveil new LED products extending the range of wavelengths available to consumers.

Toshiba America Electronic Components (TAEC), US, has added bluish-green and reddish-purple LEDs to its range of light emitters.

"These devices are variations of the white LEDs which use Toshiba's unique approach, and the new colors are expected to be in great demand for automotive applications," said Masanobu Sato, optoelectronics business manager for TAEC.

Blue-green LED

The devices use a 390-nm LED based on indium gallium nitride to activate a red-green-blue-emitting phosphor. By carefully balancing the composition of the phosphor, Toshiba is able to vary and control the broadband emission of the LED, in this case making the two new colors.

TAEC claims its bluish-green device, the TLBGA1100, offers a typical luminosity of 100 millicandela at 20 mA while the reddish-purple TLRPA1100 provides 70 millicandela at 20 mA. Samples and production quantities of each are available now.

This announcement coincides with news from fellow US firm Lumileds Lighting that it will release a warm-white LED in August. "Warm white" means that the device emits white light with a lower correlated color temperature (CCT). This eliminates the blue-tinge that is traditionally associated with cool-white LEDs, which are said to have a high CCT.

Like Toshiba, Lumileds has achieved this result by making modifications to the composition of the phosphor coating the LED. The new warm-white LED, the latest addition to the company's Luxeon range, will have a CCT of 3200 K, a typical color rendering index in excess of 85 and an average light output of 22 lumens.

"LEDs are rapidly gaining traction in general lighting because of their compelling advantages over traditional light sources, but lighting designers have been waiting for a warm white emitter to put many of their design concepts into action," said Jason Posselt, Lumileds' director of product marketing. "With our new Luxeon product poised to meet this demand, we expect the market for solid-stage lighting to explode."

Author
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.