[In Depth] Incandescent lights go green
Incandescent light bulbs have changed little since Thomas Edison perfected them in 1878. But now, researchers report that they've tripled the efficiency of an incandescent, making it nearly as efficient as a commercial LED. They did so by reworking the light bulb's metal light emitter into a flat sheet and flanking it on either side with nanostructured mirrors. The mirrors allow visible light to pass through, but they reflect infrared light back to the emitter, where it's absorbed and some of the energy is re-emitted as visible light. The researchers now hope to improve their mirrors to make their new-age incandescents far more efficient than today's best LEDs and compact fluorescents. That could save energy and reduce carbon dioxide emissions, while still giving us the warm, yellowish white glow we love from incandescent lights. Author: Robert F. Service