LEDs Light Times Square, But Can They Light Your Office?

LEDs Light Times Square, But Can They Light Your Office?

The invention of the bright-white light-emitting diode (LED) in the 1990s marked the beginning of a revolution in lighting. Cheap, long-lasting, and needing little power, bright LEDs are increasingly the light source of choice for flashlights, traffic signs, even the brilliant marquees in places like New York City’s Times Square. They are also used to illuminate the picture in some large-screen TVs. But LEDs still have not made much headway in our homes and offices, where the general lighting provided by incandescents and fluorescents is still superior.

Part of the reason is that individual LEDs are typically quite small; the surface area of the semiconductor material that emits light is only about one square millimeter. As a consequence, a bright LED, of the kind found in a flashlight, might produce 80 lumens (a lumen is a standard measure of how powerful a light source appears). A 100-watt incandescent bulb, in contrast, typically emits about 1,500 lumens. To approach this level of brightness,lighting manufacturers have arranged LEDs in arrays, which is a bulky solution at best. Some have made individual small LEDs as bright as 1,000 lumens, but these are expensive and still function best as spotlights, not as arealighting for a room.
Now Luminus Devices hopes to break into the general lighting realm with its LED PhlatLight. Derived from research the firm’s founders did at MIT, the PhlatLight is a much bigger LED, with a light-emitting area of 12 square milli­meters. A single such LED can generate up to 3,300 lumens. PhlatLights have already been used to backlight large LCD screens, replacing the necessary thousands of LEDs with a few dozen