Illumination apparatus, projector, and polarization conversion element

A polarization conversion element comprising:

• a splitting section adapted to split incident light with an asymmetric intensity distribution into transmitted light and reflected light having the polarization states different from each other in a direction in which the intensity distribution of the incident light is asymmetric;
• and
• a conversion section adapted to convert the polarization state of one of the transmitted light and the reflected light (hereinafter referred to as one light) into the polarization state of the other of the transmitted light and the reflected light,
• wherein a mirror system adapted to emit the other light and the one light, which is converted by the conversion section, in substantially the same direction is configured to include the splitting section,
• a reflecting surface included in the mirror system is disposed so that a direction in which an intensity distribution of the one light emitted from the mirror system is asymmetric is reversed with respect to a direction in which an intensity distribution of the other light emitted from the mirror system is asymmetric, and
• the mirror system is arranged such that the one light is reflected by the mirror system one or more times, the other light is reflected by the mirror system one or more times, and a difference between a number of times of reflection of the one light in the mirror system and a number of times of reflection of the other light in the mirror system is an odd number.