# US 2021/0239979 A1 · Head Mounted Display Device with Double Faceted Optics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0239979 A1 - Document ID: US20210239979A1 - Status: Published application - Kind: A1 - Application number: 16/779,220 - Filed: 2020-01-31 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: Microsoft Technology Licensing, LLC - Applicants: Microsoft Technology Licensing, LLC - Inventors: Andreas Georgiou; Alfonsus D. Lunardhi; Joel Steven Kollin; Bernard C. Kress; Ishan Chatterjee; Mario Possiwan - Web page: https://patentgrep.com/patent/US20210239979A1 ## CPC - G02B 27/0172: {characterised by optical features} - G02B 3/0056: {arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses (G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085)} - G02B 27/0093: {with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking} - G02B 27/30: Collimators - G02B 2027/0178: {Eyeglass type (eyeglass details G02C)} - G02B 2027/0187: {slaved to motion of at least a part of the body of the user, e.g. head, eye} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract This document relates to head mounted display devices. In one example the head mounted display device includes a light engine including an array of individually controllable pixels that can be energized to emit light. The example also includes an optical assembly physically aligned with the light engine and including a set of focusing elements facing toward the light engine and a different set of focusing elements facing away from the light engine. ## Claims ### Claim 1 A head mounted display device, comprising: a light engine configured to generate light corresponding to image data; a housing configured to be positioned relative to a head of a user and to position the light engine in front of an eye of the user along an optical axis extending from the eye; and, an optical assembly positioned by the housing between the light engine and the eye along the optical axis, the optical assembly comprising: a first sub-assembly positioned proximate to the light engine and configured to focus the light toward an eye box a defined distance toward the user from the optical assembly; and, a second sub-assembly positioned distal to the light engine and configured to collimate at least some of the light toward the eye box to form an image in the eye box. ### Claim 2 (depends on 1) The head mounted display device of claim 1, wherein the first sub-assembly comprises a single lens, multiple lenses, or a lens and a prism. ### Claim 3 (depends on 2) The head mounted display device of claim 2, wherein the second sub-assembly comprise multiple coplanar lenses. ### Claim 4 (depends on 3) The head mounted display device of claim 3, wherein the multiple coplanar lenses are all a same size or wherein the multiple coplanar lenses are at least two different sizes. ### Claim 5 (depends on 3) The head mounted display device of claim 3, wherein only a subset of the multiple coplanar lenses is used to create a portion of the eye box and another subset of the multiple coplanar lenses are used to create another portion of the eye box. ### Claim 6 (depends on 3) The head mounted display device of claim 3, wherein the multiple coplanar lenses comprise multiple coplanar planoconvex lenses. ### Claim 7 (depends on 6) The head mounted display device of claim 6, wherein the multiple coplanar planoconvex lenses are oriented in a two-dimensional array. ### Claim 8 (depends on 6) The head mounted display device of claim 6, wherein all of the lenses of the multiple coplanar planoconvex lenses have the same shape or wherein individual lenses of the multiple coplanar planoconvex lenses have dissimilar shapes. ### Claim 9 (depends on 1) The head mounted display device of claim 1, further comprising an eye tracking unit positioned by the housing to identify a pupil location and size relative to the eye box and a gaze direction of the eye. ### Claim 10 (depends on 9) The head mounted display device of claim 9, further comprising a controller configured to determine an optical path between the light engine and the pupil location. ### Claim 11 (depends on 9) The head mounted display device of claim 9, configured to receive the image data and further configured to customize the image data based upon the pupil location and/or the gaze direction. ### Claim 12 (depends on 11) The head mounted display device of claim 11, wherein the controller is configured to enhance image data associated with portions of the image in the eye box that are perceivable by the user from the pupil position and gaze direction. ### Claim 13 (depends on 12) The head mounted display device of claim 12, further comprising correction data relating to the optical assembly stored on storage of the device, and wherein the controller is configured to adjust driving the light engine in relation to image data based at least in part upon the correction data. ### Claim 14 (depends on 11) The head mounted display device of claim 11, wherein the light engine comprises multiple independently controllable pixels and wherein the controller is configured to customize the image data and to turn off individual pixels that would produce the light that would not be perceptible to the user based upon the eye position and the gaze direction. ### Claim 15 (depends on 11) The head mounted display device of claim 11, wherein the controller is configured to control individual pixels that produce the light that is directed to a foveal region of the eye differently than individual pixels that produce the light that is directed to non-foveal regions of the eye. ### Claim 16 A head mounted display device, comprising: a light engine configured to generate light corresponding to image data; a housing having an inwardly facing side and an outwardly facing side, the inwardly facing side configured to be engaged by a head of a user to position the housing relative to an eye of the user; and, an optical assembly and the light engine positioned by the housing transverse to an axis extending through the eye, the optical assembly comprising: a first sub-assembly positioned proximate to the light engine and having a surface profile facing the light engine that has a low rate of curvature proximate to the axis at a center of the first sub-assembly and an increasing rate of curvature toward a periphery of the first sub-assembly; and, a second sub-assembly positioned distal to the light engine and comprising multiple coplanar convex lenses configured to collimate at least some of the light toward an eye box positioned proximate to the inwardly facing side. ### Claim 17 (depends on 16) The head mounted display device of claim 16, wherein the first sub-assembly comprises a first number of lenses and the second sub-assembly comprises a second different number of lenses. ### Claim 18 (depends on 16) The head mounted display device of claim 16, further comprising an isolation structure positioned between the light engine and the optical assembly, the isolation structure configured to allow the light to travel parallel to the axis and to block light traveling at other orientations. ### Claim 19 (depends on 18) The head mounted display device of claim 18, wherein the isolation structure comprises alternating optically opaque and optically transparent regions. ### Claim 20 A head mounted display device, comprising: a light engine comprising an array of individually controllable pixels that can be energized to emit light; and, an optical assembly physically aligned along an optical axis with the light engine and comprising a set of focusing elements facing toward the light engine and a different set of focusing elements facing away from the light engine.