# US 10,502,876 B2 · Waveguide optics focus elements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,876 B2 - Document ID: US10502876B2 - Status: Granted - Kind: B2 - Application number: 13/477,646 - Filed: 2012-05-22 - Published: 2013-11-28 - Granted: 2019-12-10 - Earliest claimed: 2012-05-22 - Assignees: Microsoft Technology Licensing, LLC - Applicants: Steven John Robbins; Ian Anh Nguyen; David D. Bohn - Inventors: Steven John Robbins; Ian Anh Nguyen; David D. Bohn - Web page: https://patentgrep.com/patent/US10502876B2 ## CPC - G02B 5/18: Diffraction gratings {(holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44)} - G02B 27/0172: {characterised by optical features} - G02B 2027/0127: {comprising devices increasing the depth of field} - G02B 2027/0134: {of stereoscopic type} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract In embodiments of waveguide optics focus elements, an imaging structure includes a waveguide for viewing of an environment that is viewable with the imaging structure. The waveguide transmits light of a virtual image that is generated to appear as part of the environment for augmented-reality imaging or virtual-reality imaging. The imaging structure also includes one or more focus elements that are integrated in the waveguide and switchable to focus the virtual image at a focus depth that approximately correlates to a focal distance of the environment. The focus elements can each be implemented for a different focus depth of the virtual image, and the focus depth is adjustable based on a combination of the focus elements being switched-on or switched-off. ## Claims ### Claim 1 An imaging structure, comprising: a waveguide configured for viewing of an environment that is viewable, by a user, with the imaging structure, the waveguide further configured to transmit light of a virtual image that is generated by an image microdisplay to appear as part of the environment; and two or more focus elements integrated within the waveguide such that the environment is viewable by the user through the two or more focus elements, wherein individual focus elements are configured to be electronically switchable to an on state where the individual focus elements focus the light of the virtual image while the light of the virtual image is within the waveguide or an off state where the individual focus elements do not focus the light of the virtual image within the waveguide, wherein electronic switching of the two or more focus elements is effective to variably focus the light of the virtual image at a plurality of virtual image focus depths while the light of the virtual image is within the waveguide, wherein the plurality of virtual image focus depths approximately correlate to environment focus depths as perceived by the user, the environment focus depths determined by information from one or more sensors. ### Claim 2 (depends on 1) An imaging structure as recited in claim 1, wherein one of: the waveguide is configured for see-through viewing of the environment for augmented-reality viewing of the light of the virtual image in the environment; or the waveguide is configured for display viewing of the light of the virtual image and the environment that are generated for virtual-reality viewing. ### Claim 3 (depends on 1) An imaging structure as recited in claim 1, wherein the two or more focus elements are each configured for a different virtual image focus depth, and the two or more focus elements are electronically switchable without changing position relative to the waveguide. ### Claim 4 (depends on 1) An imaging structure as recited in claim 1, wherein different virtual image focus depths are provided when different combinations of the two or more focus elements are switched-on or switched-off. ### Claim 5 (depends on 1) An imaging structure as recited in claim 1, wherein the two or more focus elements are arranged so that the light of the virtual image travels through all of the two or more focus elements irrespective of whether the two or more focus elements are in the on state or the off state. ### Claim 6 (depends on 1) An imaging structure as recited in claim 1, wherein the two or more focus elements comprise at least one of: switchable output diffractive devices; switchable output reflective devices; or Switchable Bragg Gratings. ### Claim 7 (depends on 1) An imaging structure as recited in claim 1, wherein the two or more focus elements comprise: a first switchable output diffractive device configured to focus the light of the virtual image traveling in the waveguide at infinity when switched-on, and propagate the light of the virtual image down the waveguide when switched-off; a second switchable output diffractive device configured to focus the light of the virtual image traveling in the waveguide an intermediate virtual image focus depth when switched-on, and propagate the light of the virtual image down the waveguide when switched-off; and a third switchable output diffractive device configured to focus the light of the virtual image traveling in the waveguide at a near virtual image focus depth when switched-on, and propagate the light of the virtual image down the waveguide when switched-off. ### Claim 8 A method, comprising: transmitting light of a virtual image in a waveguide, the virtual image generated by an image microdisplay to appear as part of an environment that is viewable by a user through the waveguide; and variably focusing the light of the virtual image to a plurality of different virtual image focus depths as the light of the virtual image travels through the waveguide, the variably focusing comprising controlling two or more focus elements that are contained within the waveguide and sequentially in a path of the light of the virtual image. ### Claim 9 (depends on 8) A method as recited in claim 8, further comprising: determining a particular focal distance of the environment based at least on focus adjust data that indicates an eye accommodation distance of the user; and based at least on the particular focal distance of the environment, selecting a particular focus distance at which to focus the light of the virtual image via the two or more focus elements that are contained within the waveguide. ### Claim 10 (depends on 8) A method as recited in claim 8, wherein the variably focusing comprises: selectively controlling different combinations of the two or more focus elements to be switched-on or switched-off, each combination corresponding to a particular virtual image focus depth. ### Claim 11 (depends on 8) A method as recited in claim 8, wherein the two or more focus elements comprise one of switchable output diffractive devices or switchable output reflective devices. ### Claim 12 (depends on 8) A method as recited in claim 8, wherein the two or more focus elements comprise Switchable Bragg Gratings. ### Claim 13 A wearable display device, comprising: left and right display lens systems configured for augmented reality imaging; left and right imaging units of the respective left and right display lens systems configured to generate an augmented reality image; and a processor or controller, each of the left and right imaging units comprising: a waveguide configured for see-through viewing of an environment that is viewable by a user through the waveguide, the waveguide further configured to transmit light of a virtual image that is generated by an image microdisplay to appear as part of the environment; and two or more focus elements that are: integrated within the waveguide such that the environment is viewable by the user through the two or more focus elements; and each electronically switchable as on to focus the light of the virtual image or off so as not to focus the light of the virtual image, the two or more focus elements being switchable effective to variably focus the light of the virtual image while the light of the virtual image is travelling through the waveguide at a plurality of virtual image focus depths, wherein the processor or controller is configured to control the two or more focus elements so that the variable focus of the light of the virtual image approximately correlates to focal distances of the environment perceived by the user. ### Claim 14 (depends on 13) A wearable display device as recited in claim 13, wherein the two or more focus elements are each configured for a different virtual image focus depth, and the two or more focus elements are electronically switchable without changing position relative to the waveguide. ### Claim 15 (depends on 13) A wearable display device as recited in claim 13, wherein individual virtual image focus depths of the plurality of virtual image focus depths are achieved based on different combinations of the two or more focus elements being switched-on or switched-off. ### Claim 16 (depends on 13) A wearable display device as recited in claim 13, embodied as glasses or a head-mounted display. ### Claim 17 (depends on 13) A wearable display device as recited in claim 13, wherein the two or more focus elements comprise one of switchable output diffractive devices or switchable output reflective devices. ### Claim 18 (depends on 13) A wearable display device as recited in claim 13, wherein the two or more focus elements comprise Switchable Bragg Gratings. ### Claim 19 (depends on 13) A wearable display device as recited in claim 13, wherein the two or more focus elements comprise: a first switchable output diffractive device configured to focus the light of the virtual image traveling within the waveguide at infinity when switched-on, and propagate the light of the virtual image down the waveguide when switched-off; a second switchable output diffractive device configured to focus the light of the virtual image traveling within the waveguide at an intermediate virtual image focus depth when switched-on, and propagate the light of the virtual image down the waveguide when switched-off; and a third switchable output diffractive device configured to focus the light of the virtual image traveling within the waveguide at a near virtual image focus depth when switched-on, and propagate the light of the virtual image down the waveguide when switched-off. ### Claim 20 (depends on 13) A wearable display device as recited in claim 13, further comprising an imaging application configured to execute on the processor and to: receive focus adjust data that indicates an eye accommodation distance of the user; determine a current focal distance of the environment based at least on the eye accommodation distance of the user; and initiate focus control signals to control a combination of the two or more focus elements switched-on or switched-off to select a particular virtual image focus depth from the plurality of virtual image focus depths to match the current focal distance of the environment.