Polarizing beam splitter apparatus and light valve image projection system

A light valve image projection system comprising:

• a light source;
• a polarizing beam splitter for transmitting a first polarized component of an incident light from said light source along a first optical axis and for reflecting a second polarized component of said incident light along a second optical axis;
• a reflection light valve for modulating a polarization state of an output light from said polarizing beam splitter and for reflecting the light thus modulated to said polarizing beam splitter;
• a quarter wave plate;
• and
• a projection lens;
• wherein an output light from said light source is incident through said polarizing beam splitter to said light valve and an effective component contained in the light reflected from said light valve is projected through said polarizing beam splitter and said projection lens on a projection screen, and wherein said quarter wave plate is arranged in a light path between said polarizing beam splitter and said light valve in such a manner that either a fast axis or a slow axis of said quarter wave plate is perpendicular to a plane containing both said first optical axis and said second optical axis.

A light valve image projection system comprising:

• a light source containing color components of three primary colors;
• a color separation means for separating an output light from said light source into lights of the three primary colors;
• three polarizing beam splitters each for transmitting a first polarized component of an incident light from said color separation means along a first optical axis and for reflecting a second polarized component of said incident light along a second optical axis;
• three reflection light valves each for modulating a polarization state of a light and reflecting the light thus modulated;
• three quarter wave plates;
• and
• three projection lenses;
• wherein each color light from said color separation means is incident through a corresponding one of said three polarizing beam splitters to a corresponding one of said three reflection light valves and an effective component contained in a light reflected from each of said three reflection light valves is projected through a corresponding one of said three polarizing beam splitters and a corresponding one of said three projection lenses on a projection screen, and wherein each of said three quarter wave plates is arranged in a light path between a corresponding one of said three polarizing beam splitters and a corresponding one of said three reflection light valves in such a manner that either a fast axis or a slow axis of each quarter wave plate is perpendicular to a plane containing both said first optical axis and said second optical axis of a corresponding one of said three polarizing beam splitters.