Shadow elimination in the backlight for a 3-D display

A light guide device, comprising:

• a light guide, the light guide comprising a light-input end and an opposing end, parallel opposing left and right sides joined to the light-input end and the opposing end, opposing front and back surfaces joined to the light-input end and the opposing end, and a birefringent film on the opposing left and right sides, the birefringent film switches a polarization of incident light;
• first and second transparent rods adjacent to the light-input end, each of the first and second transparent rods having a grating along a length of the transparent rod;
• at least one light source;
• a first polarizer which imparts a first polarization to light from the at least one light source and provides the light having the first polarization to an end of the first transparent rod to provide collimated light having the first polarization to the light-input end;
• and
• a second polarizer which imparts a second polarization, orthogonal to the first polarization, to light from the at least one light source and provides the light having the second polarization to an end of the second transparent rod to provide collimated light having the second polarization to the light-input end.

A light guide device, comprising:

• a light guide, the light guide comprising a light-input end and an opposing end, parallel opposing left and right sides joined to the light-input end and the opposing end, opposing front and back surfaces joined to the light-input end and the opposing end, and a birefringent film on the opposing left and right sides, the birefringent film switches a polarization of incident light;
• first and second slab light guides adjacent to the light-input end;
• at least one light source;
• a first polarizer which imparts a first polarization to light from the at least one light source and provides the light having the first polarization to an end of the first slab light guide to provide collimated light having the first polarization to the light-input end;
• and
• a second polarizer which imparts a second polarization, orthogonal to the first polarization, to light from the at least one light source and provides the light having the second polarization to an end of the second slab light guide to provide collimated light having the second polarization to the light-input end.