# US 10,768,432 B2 · Compact head-mounted display system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,768,432 B2 - Document ID: US10768432B2 - Status: Granted - Kind: B2 - Application number: 16/678,906 - Filed: 2019-11-08 - Published: 2020-03-26 - Granted: 2020-09-08 - Earliest claimed: 2016-02-18 - Assignees: Oorym Optics Ltd. - Applicants: Oorym Optics Ltd. - Inventors: Yaakov Amitai; Nadav Amitai - Web page: https://patentgrep.com/patent/US10768432B2 ## CPC - G02B 27/0172: {characterised by optical features} - G02B 6/00: Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings - G02B 6/0031: {Reflecting element, sheet or layer} - G02B 6/0053: {Prismatic sheet or layer; Brightness enhancement element, sheet or layer} - G02B 6/0055: {Reflecting element, sheet or layer} - G02B 6/0065: {Manufacturing aspects; Material aspects} - G02B 2027/0123: {comprising devices increasing the field of view} - G02B 2027/0125: {Field-of-view increase by wavefront division} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract There is provided an optical system, including a light-transmitting substrate having at least two parallel major surfaces, edges and an output aperture, an optical element for coupling light waves into the substrate to effect total internal reflection, at least one reflecting element positioned outside of the substrate, at least one reflecting surface having at least one active side located between the two major surfaces of the light-transmitting substrate for coupling light waves out of the substrate, wherein light waves trapped inside the substrate are coupled out from the substrate through the output aperture substantially inclined in relation to the normal to the substrate major surfaces and are reflected from the reflecting element into a viewer's eye. An optical device for directing an image into a viewer's eye. An optical device for directing an image onto a viewer's eye is also provided. ## Claims ### Claim 1 An optical device, comprising: a light-transmitting substrate having at least two parallel major surfaces, edges and an output aperture; at least one reflecting element positioned outside of the substrate; a first reflecting surface having at least one active side located between the two major surfaces of the light-transmitting substrate for coupling light waves out of the substrate; and a second reflecting surface made on a slanted edge of the substrate and extending parallel to the reflecting surface for coupling light waves into the substrate to effect total internal reflection, wherein light waves trapped inside the substrate are coupled out from the substrate through the output aperture substantially inclined in relation to the normal to the substrate major surfaces and are reflected from said reflecting element into a viewer's eye. ### Claim 2 (depends on 1) The optical device according to claim 1, wherein the light waves trapped inside the substrate are plane light waves. ### Claim 3 (depends on 1) The optical device according to claim 1, wherein the light waves reflected by the reflecting element pass through the substrate. ### Claim 4 (depends on 1) The optical device according to claim 1, wherein reflecting element is at least one partially reflecting surface. ### Claim 5 (depends on 1) The optical device according to claim 1, wherein the reflecting element is an array of reflecting surfaces spaced apart from each other. ### Claim 6 (depends on 1) The optical device according to claim 1, wherein the reflecting element is embedded inside a transparent prism having at least two external surfaces. ### Claim 7 (depends on 6) The optical device according to claim 6, wherein one of the external surfaces of the prism is optically attached to one of the major surfaces of the substrate defining an interface plane, light waves coupled out of the substrate by the reflecting surface substantially pass through the interface plane without any significant reflectance, and light waves coupled inside the substrate are substantially reflected by the interface plane without any significant transmittance. ### Claim 8 (depends on 6) The optical device according to claim 6, wherein the prism is cemented by an optical adhesive, to one of the major surfaces of the substrate and the refractive index of the optical adhesive is substantially lower than the refractive index of the substrate. ### Claim 9 (depends on 7) The optical device according to claim 7, wherein another of the external surfaces of the prism is optically attached to a first lens. ### Claim 10 (depends on 9) The optical device according to claim 9, wherein another of the major surfaces of the substrate is optically attached to a second lens. ### Claim 11 (depends on 1) The optical device according to claim 1, wherein an angular sensitive reflecting coating is applied to the reflecting surface, the reflecting surface is substantially reflective for light waves coupled out from the substrate by the reflecting surface and the reflecting surface is substantially transparent to light waves reflected by the reflecting element and pass through the substrate. ### Claim 12 (depends on 3) The optical device according to claim 3, wherein two light rays from a single plane light wave coupled into the substrate by the second reflecting surface spaced apart from each other, are coupled-out from the substrate by the reflecting surface adjacent to each other. ### Claim 13 (depends on 1) The optical device according to claim 1, wherein the reflecting element comprises at least one polarization-sensitive reflecting surface. ### Claim 14 (depends on 13) The optical device according to claim 13, wherein the polarization- sensitive reflecting surface is reflective for one polarization and substantially transparent to an orthogonal polarization. ### Claim 15 (depends on 1) The optical device according to claim 1, wherein a portion of the reflecting surface is a non-active portion, said reflecting element is positioned such that the light waves coupled out from the substrate by the non-active part of the reflecting surface, are not reflected by the reflecting element. ### Claim 16 An optical device, comprising: a light-transmitting substrate having at least two parallel major surfaces, edges and an output aperture; an optical element for coupling light waves into the substrate to effect total internal reflection; at least one reflecting element positioned outside of the substrate, the reflecting element not coinciding with the surfaces or edges of the substrate and spaced apart from at least one of the major surfaces; and at least one reflecting surface having at least one active side located between the two major surfaces of the light-transmitting substrate for coupling light waves out of the substrate, wherein light waves trapped inside the substrate are coupled out from the substrate through the output aperture substantially inclined in relation to the normal to the substrate major surfaces and are reflected from said reflecting element to a direction substantially normal to the substrate major surfaces. ### Claim 17 An optical device for directing an image into a viewer's eye, comprising: a light-transmitting substrate having at least two parallel major planes having surfaces, edges and an output aperture, the major planes defining a space there between; an optical element for coupling light waves into the substrate to effect total internal reflection; at least one reflecting element positioned outside of the space between the major planes of the substrate; and at least one reflecting surface having at least one active side located between the two major planes of the light-transmitting substrate for coupling light waves out of the substrate, wherein light waves trapped inside the substrate are coupled out from the substrate through the output aperture substantially inclined in relation to a direction to the viewer's eye and are reflected from said reflecting element into the viewer's eye. ### Claim 18 (depends on 17) The optical device according to claim 17, wherein the viewer's eye and the output aperture are positioned at the same side of the substrate. ### Claim 19 (depends on 17) The optical device according to claim 17, wherein the viewer's eye and the output aperture are positioned at different sides of the substrate.