High efficiency optical tank for two-color liquid crystal light valve image projection with color selective prepolarization

In an optical system including means for providing light energy, first and second liquid crystal light valves, first and second cathode ray tubes for use with said first and second liquid crystal light valves, respectively, and a means for projection, an improved optical arrangement comprising:

• a container having a plurality of surfaces joined together to form a chamber suitable for holding fluid, including a first surface for providing an input aperture, second and third surfaces each providing an output aperture for polarized and an input aperture for modulated light, energy and a fourth surface for providing an output aperture;
• a prepolarizing beamsplitter mounted within said chamber for splitting and prepolarizing light energy from the source into first and second beams having first and second polarization states respectively;
• a first dichroic separator mounted within said chamber for extracting light energy of a first color from said first beam and a second dichroic separator for extracting light energy of a second color from said second beam;
• means mounted in said chamber for combining the output of the first and second separators to form a single beam;
• and
• a main polarizing beamsplitter mounted in said chamber for directing light of a first color and polarization through the second aperture to the first liquid crystal light valve and light energy of a second color and polarization through the third aperture to the second liquid crystal light valve and directing intensity modulated light energy through said fourth aperture to a means for projection, wherein said prepolarizing beamsplitter and said main polarizer have transverse axes and each beamsplitter is mounted so that the beamsplitter transverse axes are oriented at a relative 90.degree. angle.

A unitary arrangement comprising:

• a first polarizing beamsplitter for substantially splitting and polarizing light from a source into first and second beams having S and P polarization states, respectively;
• a first dichroic separator for substantially extracting red light from said first beam;
• a second dichroic separator for substantially extracting green light from said second beam;
• means for combining the outputs of said first and second dichroic separators into a single beam;
• and
• a second polarizing beamsplitter for polarizing the single beam and directing red light to a first surface and green light to a second surface, wherein the first and second polarizing beamsplitters have transverse axes and each beamsplitter is mounted so that the beamsplitter transverse axes are oriented at a relative 90.degree. angle.