Scientists Work to Create Warm LED Light

Electronics giant Philips is re-imagining the LED, working towards a light that would be closer to natural light or at least the “good” glow of the old incandescents. The concern with LED has been its “cold” blue-tinted light which has been stable regardless of intensity or dimming.

The company, working with Eindhoven University of Technology in the Netherlands, has developed an LED coating which adds red to the LED bulb spectrum as amps are decreased. The innovation grew out of observations that color shifts in LED bulbs occur with coated textiles or transparent materials.

Researcher Hugo Cornelissen, a Principal Scientist, Optics Research Department, Philips Research, Eindhoven, explains the development shifts the color spectrum emitted by LEDs by adding phosphor to the LED. It causes the bulb to absorb part of the blue light and re-emit it as different color. When new color combines with the residual LED blue light, the result is a “warmer” white light.

Their composite bulb coating of heated liquid-crystals and polymers shifts light as bulb temperature shifts. The lower temperatures (less amps) have that warmer glow; greater temperatures (more amps) have more of the typical blue glow of the LED.

Coatings must be fine-tuned to industry lighting standards and colors. Current research and development is focusing on reliability with actual products to be marketed within two years. Cornelissen, looking ahead, notes that this new technology will make it possible to accommodate the marketplace “where there is a need to create a warm and cozy atmosphere.”

I, Dr. Bulb, love seeing advancements in LED technology, as it will certainly accelerate the adoption of energy-efficient lighting.

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