History: 350mA and hex boards
Have you ever wondered why power LEDs are tested at 350mA,
or where the de facto standard 20mm hex board came from?
Jason Posselt, now vice-president of marketing at Bridgelux, was at Lumileds when the firm was pulling together a product specification for the first white lighting LED.
“The 350mA decision was made by a few of us in a room in 1998,” he says.
“We didn’t know about InGaN much then, so we looked at current density of some of our AlInGaP automotive products and scaled the die size.”
When the first Lumileds product came out, the 1W Luxeon, it came in three versions: the surface-mount Emitter, the /O which was a screw-down square board with a secondary lens, and the Luxeon Star – an Emitter on the now famous 20mm hexagonal board mounted on two 3mm screws spaced at 19mm centres.
“We had a square design. Industrial designer Dina Hadi invented the Star board to pack sources closer together,” says Posselt.
This information was originally published Electronics Weekly’s big guide to costing leds.
Images of Emitters, Stars and /Os are pretty hard to come by, even on Lumiled’s site. This picture comes from Elektrolumens, started and still run by Wayne Johnson, which was one of the first companies anywhere to make high-powered LED flashlights, and is now making some amazing devices – take a look at the Kong.