# US 10,481,399 B2 · Systems and methods for optical systems with exit pupil expander > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,481,399 B2 - Document ID: US10481399B2 - Status: Granted - Kind: B2 - Application number: 15/710,055 - Filed: 2017-09-20 - Published: 2018-05-03 - Granted: 2019-11-19 - Earliest claimed: 2016-09-21 - Assignees: Magic Leap, Inc. - Applicants: Magic Leap, Inc. - Inventors: John Graham Macnamara - Web page: https://patentgrep.com/patent/US10481399B2 ## CPC - G02B 27/0172: {characterised by optical features} - G02B 6/0076: {Stacked arrangements of multiple light guides of the same or different cross-sectional area} - G02B 27/0081: {with means for altering, e.g. enlarging, the entrance or exit pupil} - G02B 27/0176: {characterised by mechanical features} - G06T 19/006: {Mixed reality (object pose determination, tracking or camera calibration for mixed reality G06T7/00)} - G02B 6/34: utilising prism or grating {(G02B6/293 takes precedence)} - G02B 2027/0125: {Field-of-view increase by wavefront division} - G02B 2027/0134: {of stereoscopic type} - G02B 2027/0154: {with movable elements} - G02B 2027/0178: {Eyeglass type (eyeglass details G02C)} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract Architectures are provided for expanding the exit pupil of systems including one or more waveguides. Various embodiments include a display device including one or more waveguides. One or more physical/optical parameters of the one or more waveguides and/or a wavelength of light input to the waveguide can be varied as the angle at which incoming light is incident on the waveguide varies in order to maintain phase correlation between different beamlets of the output light beam emitted from the one or more waveguides. ## Claims ### Claim 1 An optical system comprising: an image projection system, the image projection system configured to emit a coherent beam of light at a plurality of wavelengths in the visible spectral range; a waveguide comprising a first edge, a second edge and a pair of reflective surfaces disposed between the first and the second edges, the pair of reflective surfaces separated by a gap having a gap height d, the waveguide comprising a material having a refractive index n, the pair of reflective surfaces having a reflectivity r, the beam emitted from the image projection system being coupled into the waveguide at an input angle θ; and a control system configured to vary at least one parameter selected from the group consisting of: a wavelength from the plurality of wavelengths, the gap height d, the refractive index n and the reflectivity r, wherein the variation of the at least one parameter is correlated with variation in the input angle θ such that the equation 2nd sin θ=mλ is satisfied for values of the input angle θ, wherein m is an integer and λ is wavelength of the beam. ### Claim 2 (depends on 1) The optical system of claim 1, wherein the image projection system is configured to vary the input angle θ of emitted beam at a scan rate. ### Claim 3 (depends on 2) The optical system of claim 2 wherein the control system is configured to modulate the at least one parameter at a modulation rate substantially equal to the scan rate. ### Claim 4 (depends on 1) The optical system of claim 1, wherein the least one parameter is a wavelength from the plurality of wavelengths. ### Claim 5 (depends on 1) The optical system of claim 1, wherein the least one parameter is the gap height d. ### Claim 6 (depends on 1) The optical system of claim 1, wherein the least one parameter is the refractive index n. ### Claim 7 (depends on 1) The optical system of claim 1, wherein the least one parameter is the reflectivity r. ### Claim 8 (depends on 1) The optical system of claim 1, wherein the image projection system comprises a fiber. ### Claim 9 (depends on 1) The optical system of claim 1, wherein the emitted beam is collimated. ### Claim 10 (depends on 1) The optical system of claim 1, wherein the plurality of wavelengths comprises wavelengths in the red, green and blue spectral regions. ### Claim 11 (depends on 1) The optical system of claim 1, wherein the waveguide comprises an acousto-optic material. ### Claim 12 (depends on 1) The optical system of claim 1, wherein the waveguide comprises a piezo-electric material. ### Claim 13 (depends on 1) The optical system of claim 1, wherein the waveguide comprises an electro-optic material. ### Claim 14 (depends on 1) The optical system of claim 1, wherein the waveguide comprises a micro-electro mechanical system (MEMS). ### Claim 15 (depends on 1) The optical system of claim 1, wherein the waveguide is configured as an exit pupil expander that expands and multiplies the emitted beam. ### Claim 16 (depends on 1) The optical system of claim 1, wherein the waveguide is configured to expand the beam to a spot size greater than 1 mm. ### Claim 17 (depends on 1) The optical system of claim 1, integrated in an augmented reality (AR) device. ### Claim 18 (depends on 1) The optical system of claim 1, integrated in a virtual reality (VR) device. ### Claim 19 (depends on 1) The optical system of claim 1, integrated in a near-to-eye display device. ### Claim 20 (depends on 1) The optical system of claim 1, integrated in an eyewear comprising at least one of: a frame, one or more lenses or ear stems. ### Claim 21 An optical system comprising: an image projection system, the image projection system configured to emit a coherent beam of light at a plurality of wavelengths in the visible spectral range; and a plurality of stacked waveguides, each waveguide comprising: a first edge, a second edge and a pair of reflective surfaces disposed between the first and the second edges, the pair of reflective surfaces separated by a gap having a gap height d, the waveguide comprising a material having a refractive index n, the pair of reflective surfaces having a reflectivity r; and a control system configured to vary at least one parameter selected from the group consisting of: a wavelength from the plurality of wavelengths, the gap height d, the refractive index n and the reflectivity r, wherein the beam emitted from the image projection system is coupled into the waveguide at an input angle θ, and wherein the variation of the at least one parameter is correlated with variation in the input angle θ such that the equation 2nd sin θ=mλ is satisfied for values of the input angle θ, wherein m is an integer and λ is wavelength of the beam. ### Claim 22 (depends on 21) The optical system of claim 21, wherein each waveguide has an associated depth plane, wherein the beam emitted from each waveguide appears to originate from that waveguide's associated depth plane. ### Claim 23 (depends on 21) The optical system of claim 21, wherein different waveguides from the plurality of stacked waveguides have different associated depth planes. ### Claim 24 (depends on 21) The optical system of claim 21, integrated in an augmented reality (AR) device. ### Claim 25 (depends on 21) The optical system of claim 21, integrated in a virtual reality (VR) device. ### Claim 26 (depends on 21) The optical system of claim 21, integrated in a near-to-eye display device. ### Claim 27 (depends on 21) The optical system of claim 21, integrated in an eyewear comprising at least one of: a frame, one or more lenses or ear stems.