| 摘要 |
PROBLEM TO BE SOLVED: To provide an LED device comprising a phosphorescence conversion substrate that converts the primary light of blue emitted by the LED into one or more other wavelengths of light that combines with unconverted primary light to produce white light. SOLUTION: This substrate is a single crystal phosphor having desired luminescent properties. The single crystal phosphor has the necessary lattice structure to promote single crystal growth of the light emitting structure of the LED device. Moreover, the thermo-mechanical properties of the substrate are such that excess strain or cracks in the epitaxial films of the LED device is prevented. The characteristics of the substrate, i.e., the dopant concentration and thickness, are capable of being precisely controlled and tested before the LED device is manufactured so that the fraction of primary light that passes through the substrate without being converted is predictable and controllable. Likewise, the fraction of primary light that is converted into one or more other wavelengths is predictable and controllable. By precisely controlling there fractions, phosphorescence conversion LED device can be achieved that produce uniform, high quality white light. |
