Polarization luminaire and projection display

A projector, comprising:

• a luminaire;
• modulation means for modulating polarized light of a luminous flux outputted from the luminaire, the modulation means including a liquid crystal light valve that modulates the light based on image information;
• and
• a projection optical system that projects the modulated luminous flux onto a screen to display an image therein, wherein the luminaire includes:
• a light source emitting a light having random polarization directions;
• and
• an optical integrator, the optical integrator including:
• a first lens plate having a first plurality of lenses;
• a second lens plate having a second plurality of lenses, the light emitted from the light source being projected through the first lens plate on a plane of incidence of each of the second plurality of lenses of the second lens plate to form a secondary light source image therein an object being radiated with light emitted from the second lens plate;
• polarized light splitting means disposed on one of an entrance side and an exit side of the first lens plate of the optical integrator for splitting the light emitted from the light source into two kinds of polarized lights, polarization directions of the two kinds of polarized lights being perpendicular to each other and traveling directions of the two kinds of polarized lights being separated by a first angle of less than 90 degrees;
• and
• polarization conversion means for modifying the polarization directions of the two kinds of polarized lights to be the same, wherein the polarized light splitting means comprises:
• a prism substrate;
• a glass substrate;
• and
• a liquid crystal layer, the liquid crystal layer being sandwiched between the prism substrate and the glass substrate, wherein an interface between the liquid crystal layer and the prism substrate is formed as a multi-stage surface inclined at an angle of less than 90 degrees relative to an optical axis of the polarized light splitting means.