Tunable White Light Based on Polarization-Sensitive LEDs

Brief Description

Polarized white LEDs that can improve system efficiency by removing the need for an external polarizer.

Background

Commercially available white light-emitting diodes (LEDs) emit unpolarized light and have a fixed color after they are fabricated. Options for polarizing the emission involve costly polarization plates. Tuning the white light involves using a number of different-colored LEDs and changing their intensity individually, or introducing different-colored, fluorescent organic dyes as quantum-well light emitting layers or conjugated hybrid polymers. These methods have manufacturing hurdles and low efficiency.

Description

UC Santa Barbara researchers have created polarized white LEDs that can improve system efficiency by removing the need for an external polarizer. Alternatively, the color-rendering properties of these LEDs can be manipulated through use of a polarizing element. The color of the LED can be easily changed after it is produced by simply rotating the polarizing element. This allows an end user to adjust the LED to their preference for white light.

Advantages

• Polarized white emission can reduce system complexity and cost
• Hue of white light is tunable by end user after fabrication
• Less costly and simpler than other white light LED manufacturing methods

Applications

• LEDs
• Applications that require uniform color illumination such as display backlighting, two- and three-dimensional image projectors, and architectural lighting

Patent Status