Illumination optical system and projector

A projector, comprising:

• an illumination optical system;
• a display device having an image display surface to be illuminated by the illumination optical system;
• and
• a projection optical system that magnifies and projects an image formed on the image display surface onto a screen,
• wherein
• the illumination optical system is provided with:
• a first light source that emits a first light beam;
• a second light source that emits a second light beam;
• a light condensing optical system that condenses the first light beam and the second light beam;
• a polarization separation optical system that separates each of the first light beam and the second light beam into a first polarization component and a second polarization component;
• a ½ phase difference plate that converts a polarization state of the first polarization component to a polarization state equal to a polarization state of the second polarization component;
• a rod integrator that uniformizes spatial energy distribution of the first light beam and the second light beam that have undergone condensation by the light condensing optical system;
• and
• a relay optical system that forms an image of an exit face of the rod integrator on a region to be illuminated;
• wherein
• the light condensing optical system condenses the first polarization component onto a first region of an entrance face of the rod integrator, and condenses the second polarization component onto a second region of the entrance face of the rod integrator;
• and
• wherein
• the ½ phase difference plate is placed at the first region of the entrance face of the rod integrator or at a position conjugate with the first region of the entrance face of the rod integrator.