Fraunhofer: Plastic lenses that channel light from LEDs

Licensing opportunity

The Fraunhofer Institute for Production Technology IPT in Aachen, Germany, has developed plastic lenses which, when applied to light-emitting diodes, concentrate and direct light, evenly illuminating an entire target area.

LEDs are light sources that deliver an optical output that consumes one-hundredth the energy of conventional light bulbs, albeit providing a similar optical output. But as a means of illumination, LEDs have been less effective than less energy-efficient light bulbs.

The IPT researchers have developed optical lenses which, when applied to LEDs, redirect light. Christian Wenzel, from the Fraunhofer Institute for Production Technology, says: “A light-emitting diode is a single-point light source that emits light in a large, uncontrolled area. We use special lenses to direct all of the light to the place where it is needed, thus increasing the efficiency of the LEDs. The spot of light created by the light source does not therefore fade out at the edges, but has a sharply defined edge.”

This light channelling technology exploits the energy-efficiency of LEDs while illuminating an entire target area as effectively as conventional light bulbs. The technique relies on highly accurate casting of plastic lenses using injection-moulding, a method which, Wenzel says, will enable low-cost manufacture of large batches of lenses.

Accuracy is tested by assessing the curvature, inclination and shape of the lens by measuring the distortion of projected stripes projected. The production of this technology has been optimised, and IPT researchers will present this optical lens producing technique at the Optatec trade fair in Frankfurt in June 2008.