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

An illumination optical device, comprising:

• a light source;
• a light splitting element that splits a light beam from the light source into a plurality of areas;
• and
• a polarization converter, the polarization converter including:
• a plurality of polarization separating films inclined relative to incident light beam, the polarization separating films separating the incident light beam into two linearly polarization beams;
• a plurality of reflecting films alternately disposed in parallel between the polarization separating films, the reflecting films reflecting 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;
• a plurality of retardation plates provided on a light-irradiation side of the light-transmissive member, the retardation plates converting the polarization axis of the one of the polarization beams;
• and a pair of polarizing conversion elements, the polarizing conversion elements being combined so that the polarization separating films and the reflecting films of the polarizing conversion elements are symmetrically arranged around a contact surface of the polarizing conversion elements, wherein the retardation plate is provided on a position where the pair of polarizing conversion elements are in close contact and the retardation plate stretches over the pair of polarizing conversion elements.

A projector, comprising:

• an illumination optical device having a light source;
• a light splitting element that splits a light beam from the light source into a plurality of areas;
• and a polarization converter, the polarization converter including:
• a plurality of polarization separating films inclined relative to incident light beam, the polarization separating films separating the incident light beam into two linearly polarization beams;
• a plurality of reflecting films alternately disposed in parallel between the polarization separating films, the reflecting films reflecting 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;
• a plurality of retardation plates provided on a light-irradiation side of the light-transmissive member, the retardation plates converting the polarization axis of the one of the polarization beams;
• and a pair of polarizing conversion elements, the polarizing conversion elements being combined so that the polarization separating films and the reflecting films of the polarizing conversion elements are symmetrically arranged around a contact surface of the polarizing conversion elements, wherein the retardation plate is provided on a position where the pair of polarizing conversion elements are in close contact and the retardation plate stretches over the pair of polarizing conversion elements;
• a plurality of optical modulators that modulates the light beam irradiated by the illumination optical device in accordance with image information;
• and
• a color combining optical device that combines the light beam modulated by the plurality of optical modulators.