LED illumination system with polarization recycling
Assignee3M Innovative Properties Company
InventorsWilliam E. Phillips, III, Ronald E. English, Jr., Patrick R. Destain
Life of this patent
Estimating the term…
Abstract
A light engine has a light source front surface that emits non-collimated light. A collection lens collects the non-collimated light and provides incompletely collimated light. A collimating lens receives the incompletely collimated light and provides a collimated image. A non-orthogonal polarizing filter receives the collimated image and passes a polarized portion of the collimated image as a direct component of the polarized light engine image. The non-orthogonal polarizing filter reflects a recycled image back to the front surface. The non-orthogonal shape of the polarizing filter is selected according to the pattern of light on the light source front surface.
Claims22
A light engine that provides a polarized light engine image, comprising:
- a light source that has a front surface comprising a first region and a second region;
- a collection lens that collects the non-collimated light from the front surface and that provides incompletely collimated light from the front surface;
- a collimating lens that receives the incompletely collimated light and that provides a substantially collimated image of the front surface;
- a polarizing filter that receives the collimated image of the front surface, the polarizing filter passing a polarized portion of the collimated image as a direct component of the polarized light engine image, and the polarizing filter reflecting a recycled image back to the front surface, the front surface providing the recycled image as a recycled component of the polarized light engine image;
- and
- the polarizing filter comprising a non-orthogonal shape that shifts portions of the recycled component relative to the direct component, to increase brightness uniformity of the polarized light engine image.
A light engine that provides a polarized light engine image, comprising:
- a light source that emits non-collimated light;
- a collection lens that collects the non-collimated light and that provides incompletely collimated light of the front surface;
- a collimating lens that receives the incompletely collimated light and that provides a collimated image of the front surface;
- a non-orthogonal polarizing filter that receives the collimated image of the front surface, the polarizing filter passing a polarized portion of the collimated image as a direct component of the polarized light engine image, and the polarizing filter reflecting a recycled image back to the front surface;
- the front surface providing the recycled image as a recycled component of the polarized light engine output;
- and
- a quarter wave plate between the polarizing filter and the light source.
Dependencies are inferred from the claim text.