Patent ID: 6443585
Filing Date: 2002-09-03
Classification: G02B,G02F,Y10S

Abstract:
A hollow light guide for uniformly distributing homogenized collimated light, said light guide comprising:a hollow cavity configured as a parallelepiped and further comprising, a first set of parallel faces consisting of an entrance aperture and a distal edge located a first predetermined distance in opposition thereof, and a second set of parallel faces consisting of a bottom edge and an exit aperture located a second predetermined distance in opposition thereof, said exit aperture being orthogonal to said entrance aperture; wherein said hollow cavity configured as a parallelepiped is further defined by a reference plane extending through and perpendicular to said entrance aperture and parallel to said exit aperture; a beam splitting structure covering said entrance aperture and configured to symmetrically split, about said reference plane, an incoming beam of said collimated light striking thereupon into an upper beam lobe and a lower beam lobe exiting therefrom said beam splitting structure into said hollow cavity, wherein said upper beam lobe diverges in a first direction from said reference plane and said lower beam lobe diverges in a second direction from said reference plane, said first direction directly opposing said second direction; a retarder adjacent to a first specular reflector and forming together therewith said distal edge of said hollow cavity, wherein said retarder is interposed between the interior of said hollow cavity and said first specular reflector; a second specular reflector forming said bottom edge of said hollow cavity and being geometrically positioned such that none of the lower light beam lobe is reflected therefrom to impinge upon the retarder; and a reflective polarizer adjacent to a beam directing structure and covering together therewith said exit aperture of said hollow cavity, wherein said reflective polarizer is interposed between the interior of said hollow cavity and said beam directing structure.