PROJECTION OPTICAL SYSTEM FOR COUPLING IMAGE LIGHT TO A NEAR-EYE DISPLAY
First Claim
1. A projection optical system of a projection light engine for coupling image light from an image source of the projection light engine to a near-eye display comprising:
- a support structure of a near-eye display device which may be worn by a user;
a high index glass region supported by the support structure;
a birdbath optical element having a reflective surface immersed in the high index glass region and positioned by the support structure for optically coupling image light from the image source; and
the birdbath optical element collimating and reflecting the image light through the high index glass region to an external exit pupil which is external to the projection light engine.
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Accused Products
Abstract
Technology is described for a projection optical system which optically couples image light from an image source to a near-eye display (NED) of a wearable near-eye display device. The projection optical system and the image source make up a projection light engine. Light from the image source is directed to a birdbath reflective optical element which is immersed in high index glass. The image light is reflected and collimated by the birdbath element and travels outside a housing of the projection light engine forming an external exit pupil, meaning the exit pupil is external to the projection light engine. A waveguide optically couples the image light of the external exit pupil. An example of a waveguide which can be used is a surface relief grating waveguide.
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Citations
20 Claims
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1. A projection optical system of a projection light engine for coupling image light from an image source of the projection light engine to a near-eye display comprising:
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a support structure of a near-eye display device which may be worn by a user; a high index glass region supported by the support structure; a birdbath optical element having a reflective surface immersed in the high index glass region and positioned by the support structure for optically coupling image light from the image source; and the birdbath optical element collimating and reflecting the image light through the high index glass region to an external exit pupil which is external to the projection light engine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A near-eye display device comprising:
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a near-eye support structure; a near-eye display (NED) supported by the near-eye support structure, the near-eye display including a waveguide; a projection light engine, including an image source and a projection optical system, supported by the near-eye support structure and having an external exit pupil which is external to the projection light engine; the projection optical system comprising a high index glass region in which a birdbath optical element with a reflective surface is immersed, the birdbath optical element collimates and reflects image light from the image source to the external exit pupil; and the near-eye support structure positions the waveguide for optically coupling the image light of the external exit pupil. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for coupling image light from an image source of a projection light engine to a near-eye display comprising:
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optically directing image light from the image source along a first optical path in a high index glass region within a projection optical system housing to a birdbath reflective optical element in the high index glass region; collimating and reflecting the image light by the birdbath reflective optical element along a second optical path extending through the high index glass region to an external exit pupil outside the projection optical system housing; polarizing the image light in at least one of the first optical path and the second optical path; and an input grating of a waveguide of the near-eye display optically coupling at least the image light of the exit pupil into the waveguide. - View Dependent Claims (19, 20)
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Specification