| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection illuminating device which can improve efficiency for utilizing light in an illumination system. SOLUTION: This projection illuminating device uses a light emitting diode(LED) 1 as a light source. A transparent block 10 is positioned so as to be closely adhered to the light emitting diode(LED) 1. Also, angle distribution of a light beam emitted to the block 10 from the light emitting diode(LED) 1 is 0 to 90 degrees. A shape of the block 10 for taking this all light beams and containing angle distribution of outgoing light within the prescribed angle distribution is a shape of curved surface having spread of a parabolic surface. Also, a cross-sectional shape of an incident end and an outgoing end are similar to a shape of an element to be illuminated (in this case: optical modulation element 8).
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