Polarization converter, illumination optical device having the polarization converter and projector

An illumination optical device, comprising:

• a light source;
• a light splitting optical element that splits a light beam from the light source into a plurality of sub-beams;
• and
• a polarization converter including:
• a polarizing conversion element body including a plurality of polarization separating films inclined relative to incident light beam that separate the incident light beam into two linearly polarization beams, a plurality of reflecting films that reflect one of the linearly polarization beams separated by the polarization separating film, a light-transmissive member provided with the polarization separating film and the reflecting film, and a plurality of retardation plates provided on a light-irradiation side of the light-transmissive member to convert the polarization axis of the other linearly polarization beam;
• and a light-shielding member provided on the light-incident side of the light-transmissive member at a position not to oppose the retardation plate, the light-shielding member shielding the incident light beam irradiated by the light source from entering on the polarizing conversion element body, the light-shielding member having a holder that holds an end of the polarizing conversion element body and a fixing portion for the polarization converter to be attached on an optical parts housing that houses the polarization converter.

A projector, comprising:

• an illumination optical device, including:
• a light source;
• a light beam splitting optical element that splits a light beam from the light source into a plurality of sub-beams;
• and a polarization converter including:
• a polarizing conversion element body including a plurality of polarization separating films inclined relative to incident light beam tat separate the incident light beam into two linearly polarization beams, a plurality of reflecting films that reflect one of the linearly polarization beams separated by the polarization separating film, a light-transmissive member provided with the polarization separating film and the reflecting film, and a plurality of retardation plates provided on a light-irradiation side of the light-transmissive member to convert the polarization axis of the other linearly polarization beam;
• and a light-shielding member provided on the light-incident side of the light-transmissive member at a position not to oppose the retardation plate, the light-shielding member shielding the incident light beam irradiated by the light source from entering on the polarizing conversion element body, the light-shielding member having a holder that holds an end of the polarizing conversion element body and a fixing portion for the polarization converter to be attached on an optical parts housing that houses the polarization converter;
• an optical modulator that modulates the light beam irradiated by the illuminating optical device in accordance with image information;
• and
• a projection optical device that enlarges and projects the light beam modulated by the optical modulator.