| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection type image display device which is capable of preventing the deterioration of polarization due to stress distortion of a stuck surface and preventing the color irregularity and the deterioration of contrast, and is low-cost. SOLUTION: A polarizing beam splitter 15 is composed of a polarization separation film 31 and prisms 32a, 32b combined by holding the separation film there between. The polarization separation film 31 is formed on an inclined surface 33 of one side prism 32a, and an inclined surface of another side prism 32b (stuck surface) and a dielectric multilayer film 31 are stuck with an adhesive. Thereby, the prisms 32a, 32b are joined and the polarizing beam splitter 15 is formed. When the size in the longitudinal direction of the range 35 of effective irradiation transmitted by the polarization beam splitter 15 is set to 1 and the size in the longitudinal direction of the stuck surface 34 is let to L, the following relation; 1.51≤L≤21 is satisfied. Thus, the polarizing beam splitter 15 is not affected by stress distortions generated in the vicinity of four corners of the stuck surface 34 and can maintain high polarization. COPYRIGHT: (C)2006,JPO&NCIPI
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