RAINBOW REMOVAL IN NEAR-EYE DISPLAY USING POLARIZATION-SENSITIVE GRATING
First Claim
1. An optical system, comprising:
- a polarizing filter configured to filter stray light, or light from real-world objects, into a first polarization state;
a substrate of optical material;
a first diffractive optical element (DOE) disposed on the substrate, the first DOE having an input surface and configured as an in-coupling grating to receive one or more optical beams having a second polarization state as an input; and
a second DOE disposed on the substrate and configured for pupil expansion of the one or more optical beams along a first direction,a third DOE disposed on the substrate, the third DOE having an output surface and configured for pupil expansion of the one or more optical beams along a second direction, and further configured as an out-coupling grating to out-couple, as an output display from the output surface, one or more optical beams with expanded pupil relative to the input,wherein the out-coupling grating is configured for sensitivity to the second polarization state so that only optical beams in the second polarization state are out-coupled as the output from the third DOE.
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Accused Products
Abstract
In a near-eye optical display system comprising a waveguide and diffractive optical elements (DOEs) configured for in-coupling, exit pupil expansion, and out-coupling, a rainbow phenomenon manifested in the display may be removed or reduced using a polarizing filter at the front of the system so that real-world/stray light entering the system has a particular polarization state, for example TM-polarized. The polarizing filter is utilized in conjunction with a downstream out-coupling DOE that includes diffractive grating structures that are configured to enable sensitivity to an opposite polarization state, for example TE-polarized. An imager is configured to produce virtual-world images that also have a TE-polarized state. The polarization-sensitive out-coupling DOE diffracts the TE-polarized imaging beam out of the grating for display while the TM-polarized light from the real world and/or stray light passes through the grating without diffraction and thus cannot contribute to rainbows in the display.
39 Citations
20 Claims
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1. An optical system, comprising:
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a polarizing filter configured to filter stray light, or light from real-world objects, into a first polarization state; a substrate of optical material; a first diffractive optical element (DOE) disposed on the substrate, the first DOE having an input surface and configured as an in-coupling grating to receive one or more optical beams having a second polarization state as an input; and a second DOE disposed on the substrate and configured for pupil expansion of the one or more optical beams along a first direction, a third DOE disposed on the substrate, the third DOE having an output surface and configured for pupil expansion of the one or more optical beams along a second direction, and further configured as an out-coupling grating to out-couple, as an output display from the output surface, one or more optical beams with expanded pupil relative to the input, wherein the out-coupling grating is configured for sensitivity to the second polarization state so that only optical beams in the second polarization state are out-coupled as the output from the third DOE. - View Dependent Claims (2, 3, 4, 5)
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6. An electronic device supporting a mixed reality experience including elements from a virtual world and elements from a real world, comprising:
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a data processing unit; an optical engine operatively connected to the data processing unit for receiving image data from the data processing unit; an imager operatively connected to the optical engine to form virtual images based on the image data and to generate one or more input optical beams incorporating the virtual images having a first polarization state; and an exit pupil expander, responsive to the one or more input optical beams, comprising a structure on which multiple diffractive optical elements (DOEs) are disposed, in which the exit pupil expander is configured to provide one or more out-coupled optical beams, using one or more of the DOEs, as a near-eye display with an expanded exit pupil, and wherein at least one of the DOEs has a portion configured to be polarization-sensitive so the exit pupil expander outputs the virtual images having the first polarization state as the out-coupled optical beams while passing through stray light or light associated with the real world having a second polarization state to suppress rainbowing in the near-eye display. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A method, comprising:
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receiving, from an imager, imaging light in a first polarization state at an in-coupling diffractive optical element (DOE) disposed in an exit pupil expander; utilizing a polarizing filter so that non-imaging light received from non-imager sources has a second polarization state that is opposite to the first polarization state; expanding an exit pupil of the received imaging light along a first coordinate axis in an intermediate DOE disposed in the exit pupil expander; expanding the exit pupil along a second coordinate axis in an out-coupling DOE disposed in the exit pupil expander; and outputting imaging light in a display with an expanded exit pupil relative to the received light at the in-coupling DOE along the first and second coordinate axes using the out-coupling DOE, in which the out-coupling DOE includes grating features configured for polarization-sensitivity so that the out-coupling DOE diffracts the imaging light in the first polarization state as the output from the exit pupil expander and passes the non-imaging light in the second polarization state through without diffraction to reduce rainbowing in the display. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification