Patent ID: 7922331

Claim:
A polarization conversion device, comprising: a polarization conversion unit, comprising: a polarization splitting element array including a plurality of polarization splitting films disposed obliquely to an incident light beam and for splitting the incident light beam into two types of linearly-polarized light beams, a plurality of reflecting films disposed in parallel alternately between the polarization splitting films and for reflecting either one of the linearly-polarized light beams obtained by the polarization splitting films, and a translucent member provided with the polarization splitting films and the reflecting films; a plurality of retardation plates each formed of a quartz crystal member and for converting a polarization axis of either one of the linearly-polarized light beams obtained by the polarization splitting films into a polarization axis of the other of the linearly-polarized light beams; and a spacer member having a predetermined thickness and for bonding end sections of the retardation plates to a light beam exit side of the translucent member; and a fixing frame for fixing the polarization conversion unit, wherein the fixing frame includes a first fixing frame disposed on a light beam entrance side of the polarization splitting element array, and a second fixing frame disposed on a light beam exit side of the retardation plates, the first fixing frame has a fixing section for fixing the polarization splitting element array, and the second fixing frame fixes the retardation plates to the polarization splitting element array via an elastic member.