Diffractive optical element with integrated in-coupling, exit pupil expansion, and out-coupling
First Claim
1. An optical element, comprising:
- a monolithic substrate of optical material forming a waveguide in which one or more optical beams are propagated;
an in-coupling region integrated into the monolithic substrate, the in-coupling region having an input surface and configured with a one dimensional (1D) grating that is periodic in one direction to couple one or more optical beams incident on the input surface into the waveguide; and
a beam steering and out-coupling region integrated into the monolithic substrate and configured for pupil expansion of the one or more optical beams along a first direction,wherein the beam steering and out-coupling region is configured with a two-dimensional (2D) grating that is periodic in two directions,wherein the 2D grating is configured to provide at least two diverse optical paths to each of any given point in the 2D grating for the propagating optical beams, wherein differences between lengths of the at least two diverse optical paths to each of any given point exceed a coherence length of the propagating optical beams in the beam steering and out-coupling region so as to increase uniformity of output optical beams and thereby reduce optical interference.
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Accused Products
Abstract
In an optical near eye display system, a monolithic three-dimensional optical microstructure is formed by a waveguide substrate with at least one DOE having grating regions that integrate the functions of in-coupling of incident light into the waveguide, exit pupil expansion in one or two directions, and out-coupling of light from the waveguide within a single optical element. An in-coupling region of the DOE couples the incident light into the waveguide and to a beam steering and out-coupling region. The beam steering and out-coupling region provides exit pupil expansion and couples light out of the waveguide. The beam steering and out-coupling region of the DOE can be configured with a two-dimensional (2D) grating that is periodic in two directions.
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Citations
19 Claims
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1. An optical element, comprising:
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a monolithic substrate of optical material forming a waveguide in which one or more optical beams are propagated; an in-coupling region integrated into the monolithic substrate, the in-coupling region having an input surface and configured with a one dimensional (1D) grating that is periodic in one direction to couple one or more optical beams incident on the input surface into the waveguide; and a beam steering and out-coupling region integrated into the monolithic substrate and configured for pupil expansion of the one or more optical beams along a first direction, wherein the beam steering and out-coupling region is configured with a two-dimensional (2D) grating that is periodic in two directions, wherein the 2D grating is configured to provide at least two diverse optical paths to each of any given point in the 2D grating for the propagating optical beams, wherein differences between lengths of the at least two diverse optical paths to each of any given point exceed a coherence length of the propagating optical beams in the beam steering and out-coupling region so as to increase uniformity of output optical beams and thereby reduce optical interference. - View Dependent Claims (2, 3, 4)
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5. An electronic device, 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 images based on the image data and to generate one or more input optical beams incorporating the images; and an exit pupil expander, responsive to the one or more input optical beams, comprising a monolithic waveguide structure in which one or more optical beams are propagated and on which multiple diffractive optical elements (DOEs) are integrated, in which the exit pupil expander is configured to provide one or more output optical beams, using one or more of the DOEs, as a near eye virtual display with an expanded exit pupil, and includes an in-coupling region having an input surface and configured with a one dimensional (1D) grating that is periodic in one direction to couple the one or more input optical beams incident on the input surface into the monolithic waveguide structure, wherein at least one of the DOEs has a region configured to implement beam steering and out-coupling of the one or more output optical beams from the monolithic waveguide structure, and wherein at least one of the DOEs includes a two-dimensional (2D) grating that is periodic in two directions and configured to provide at least two diverse optical paths to each of any given point in the 2D grating for the propagating one or more optical beams, wherein differences between lengths of the at least two diverse optical paths to each of any given point exceed a coherence length of the propagating one or more optical beams in the beam steering and out-coupling region so as to increase uniformity of the one or more output optical beams and thereby reduce optical interference. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A method, comprising:
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receiving light at an in-coupling region of a diffractive optical element (DOE) disposed in an exit pupil expander formed of a unitary optical structure in which one or more optical beams are propagated, wherein the in-coupling region has an input surface and is configured with a one dimensional (1D) grating that is periodic in one direction to couple the received light incident on the input surface into the exit pupil expander; expanding an exit pupil of the received light along a first coordinate axis in a beam steering and out-coupling region of the DOE; expanding the exit pupil along a second coordinate axis in a beam steering and out-coupling region of the DOE; and outputting light with an expanded exit pupil relative to the received light at the in-coupling region of the DOE along the first and second coordinate axes using the beam steering and out-coupling region, in which the beam steering and out-coupling region includes gratings configured to provide a periodic contoured surface having a first periodicity along a first direction and a second periodicity along a second direction, and wherein the gratings of the DOE are configured to provide at least two diverse optical paths to each of any given point in the gratings for the propagating one or more optical beams, wherein differences between lengths of the at least two diverse optical paths to each of any given point exceed a coherence length of the propagating one or more optical beams in the beam steering and out-coupling region so as to increase uniformity of output optical beams and thereby reduce optical interference. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification