| 摘要 |
The invention relates to light emitting devices ( 2 ) with variable output color. More specifically, the inventions provides a color conversion cell ( 10 ) which can be positioned in front of a light source ( 4 ) in order to generate other color or color temperatures. Typically the light source is a light emitting diode (LED) which is power efficient but emits in a narrow and fixed spectra. The new colors are generated by photoluminescence in fluorescent dyes contained in the cell. The color converting of the cell is electrically controllable, preferably by controlling the orientation, density or distribution of the fluorescent dyes, or by controlling a pathlength of the light in the cell.
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