Summer 2011 Intern Project- Michael Myers
PHOSPHOR IMPLEMENTATION SCHEMES FOR EFFICIENT LED-BASED WHITE LIGHT
UC Santa Barbara
Mentor: Stuart Brinkley
Faculty Advisor: Steve DenBaars
Departments: Electrical and Computer Engineering and Materials
Modern day lighting solutions include highly inefficient sources such as incandescent and compact fluorescent bulbs. Light emitting diodes (LEDs) are much more efficient, and can be coupled with phosphors to convert single wavelength light into broader spectrum white light. Differences in efficiency and color rendering arise from whether the phosphors are mixed or layered. These differences have been explored by comparing the efficiencies and color rendering of two different phosphor arrangements that produce the same coordinates on the CIE diagram. Testing was performed with silicone caps containing varying mass percents of phosphor. The caps were designed to fit one inside the other to produce a layered remote phosphor. Tests showed that the remote red-yellow layered phosphors had a higher color rendering than the equivalent single red-yellow mixture cap. However, the results also show that the single cap mixture had greater efficiency than the bilayer phosphors. These results show that higher efficiency white light can be produced using a single mixed cap with a small reduction in color rendering.