| 摘要 |
PROBLEM TO BE SOLVED: To provide an illumination optical device capable of surely cooling a light shielding plate even though the amount of cooling air is reduced. SOLUTION: The illumination optical device 50 is equipped with a polarized light conversion element 61 equipped with a plurality of polarized light separation films, a plurality of reflection films, a plurality of glass members and a plurality of phase difference plates 54, the light shielding plate 62 provided on the luminous flux incident side of the conversion element 61 and having a light shielding part formed in accordance with the array of the reflection films and intercepting unnecessary light made incident on the reflection film, and a housing 51 hermetically housing the element 61 and the plate 62 with ethyleneglycol. Thus, when the plate 62 generates heat, the ethyleneglycol (cooling liquid) around the plate 62 is made to circulate by the heat and natural convection is generated. Therefore, the plate 62 is surely cooled even though the amount of the cooling air by a cooling fan or the like is reduced. COPYRIGHT: (C)2004,JPO&NCIPI
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