Polarizing beam splitter and illuminator including same

An illuminator comprising:

• a polarizing beam splitter,
• a first reflective component disposed adjacent a first surface of the polarizing beam splitter, the first reflective component having a largest active area,
• a lens disposed adjacent a second surface of the polarizing beam splitter opposite the first surface, the lens receiving light emitted by the first reflective component;
• wherein the largest active area defines a largest acceptance area of the lens, and wherein the largest acceptance area is no greater than about half the largest active area.

A polarizing beam splitter comprising:

• a reflective polarizer,
• a first prism having a first volume and comprising:
• a first face;
• a second face adjacent the first face, an angle between the first and second faces substantially equal to 90 degrees;
• a first hypotenuse opposite the angle;
• a second prism having a second volume, the second prism a right triangular prism having third and fourth faces and having a second hypotenuse, the second hypotenuse disposed adjacent the first hypotenuse, the first and second hypotenuses having substantially equal surface areas, the third face opposite the first face and substantially parallel with the first face, the fourth face opposite the second face and substantially parallel with the second face;
• wherein the reflective polarizer is disposed between the first and second hypotenuses, and
• wherein the first volume is no greater than about half the second volume.

An illuminator comprising a light source, a lens, and a polarizing beam splitting system adapted to receive light from the light source and output light through the lens, the polarizing beam splitting system centered on a folded optical axis defined by an optical path of a central light ray emitted by the light source, the polarizing beam splitting system comprising:

• a reflective polarizer disposed between a first hypotenuse of a first prism and a second hypotenuse of a second prism, the first and second hypotenuses having substantially equal surface areas, the optical axis having a length d1 between the light source and the reflective polarizer;
• a first reflective component substantially perpendicular to the optical axis and disposed proximate a first face of the second prism such that the reflective polarizer is disposed between the first reflective component and the light source, the optical axis having a length d2 between the first face of the second prism and the reflective polarizer;
• a second reflective component substantially perpendicular to the optical axis and disposed proximate a second face of the second prism such that the reflective polarizer is disposed between the second reflective component and the lens, the optical axis having a length d3 between the second face of the second prism and the reflective polarizer,
• wherein the optical axis has a length d4 between the lens and the reflective polarizer and one or both of d1 and d4 are less than a lesser of d2 and d3.

An illuminator comprising a light source, a lens, and a polarizing beam splitting system adapted to receive light from the light source and output light through the lens, the polarizing beam splitting system centered on a folded optical axis defined by an optical path of a central light ray emitted by the light source, the polarizing beam splitting system comprising:

• a reflective polarizer defining a smallest imaginary rectangular parallelepiped entirely containing the reflective polarizer and having a surface perpendicular to the central ray;
• a first reflective component substantially perpendicular to the optical axis and disposed proximate the reflective polarizer opposite the light source;
• a second reflective component substantially perpendicular to the optical axis and disposed proximate the reflective polarizer opposite the lens,
• wherein at least a portion of the light source or at least a portion of the lens is disposed inside the smallest imaginary rectangular parallelepiped.