# US 11,906,736 B1 · Wearable pupil-forming display apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,736 B1 - Document ID: US11906736B1 - Status: Granted - Kind: B1 - Application number: 17/138,240 - Filed: 2020-12-30 - Granted: 2024-02-20 - Earliest claimed: 2020-08-03 - Assignees: Raytrx, LLC - Applicants: Raytrx, LLC - Inventors: David Kessler; Michael H. Freeman - Web page: https://patentgrep.com/patent/US11906736B1 ## CPC - G02B 27/0172: {characterised by optical features} - H04N 13/344: with head-mounted left-right displays - G02B 13/0025: {having one lens only} - G02B 13/0065: {having a beam-folding prism or mirror} - G02B 13/0095: {Relay lenses or rod lenses (in instruments for viewing the inside of hollow bodies G02B23/2446)} - G02B 27/0176: {characterised by mechanical features} - G02B 27/0179: {Display position adjusting means not related to the information to be displayed} - G02B 27/283: {used for beam splitting or combining} - G02B 27/286: {for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another (G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34)} - G02B 30/35: using reflective optical elements in the optical path between the images and the observer - G02B 30/36: using refractive optical elements, e.g. prisms, in the optical path between the images and the observer - G06F 3/013: {Eye tracking input arrangements (G06F3/015 takes precedence)} - G06T 7/50: Depth or shape recovery - G09G 3/007: {Use of pixel shift techniques, e.g. by mechanical shift of the physical pixels or by optical shift of the perceived pixels} - H04N 13/383: for tracking with gaze detection, i.e. detecting the lines of sight of the viewer's eyes - G02B 2027/0123: {comprising devices increasing the field of view} - G02B 2027/0134: {of stereoscopic type} - G02B 2027/0138: {comprising image capture systems, e.g. camera} - G02B 2027/0159: {with mechanical means other than scaning means for positioning the whole image} - G02B 2027/0187: {slaved to motion of at least a part of the body of the user, e.g. head, eye} - G09G 2340/0407: Resolution change, inclusive of the use of different resolutions for different screen areas - H04N 23/90: Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A display has an image generator; a partially transmissive mirror having a curved surface; a beam splitter to reflect incident light toward the curved surface; and an optical image relay that defines a path to relay light to a curved focal surface of a partially transmissive mirror, the curved focal surface is between a curved reflective surface of the partial mirror and the beam splitter. A prism has a folding surface in the optical path for light from the image generator, wherein an aperture stop for the relay lies within the prism. A first plano-aspheric lens, against the prism input surface, guides light from the image generator toward the folding surface; a second plano-aspheric lens, in optical contact against the prism output surface, directs light to the curved focal surface. The relay, curved mirror, and beam splitter form an exit pupil for viewing the scene with a 2D image superimposed. ## Claims ### Claim 1 A wearable display apparatus comprising: an image generator that forms a 2D image; a partially transmissive mirror having a curved focal surface and a partially transmissive curved reflective surface; a beam splitter disposed to reflect light toward the partially transmissive mirror, wherein the curved focal surface is defined in a space between the partially transmissive curved reflective surface and the beam splitter; and an optical image relay positioned between the image generator and the beam splitter, and configured to conjugate the formed 2D image from the image generator to the curved focal surface of the partially transmissive mirror, the optical image relay includes: a right-angle prism having a prism input surface, a prism output surface, and a folding surface extending from the prism input surface to the prism output surface, the folding surface is configured to fold an optical path for light generated by the image generator towards the beam splitter; a first plano-aspheric lens in optical contact against the prism input surface and configured to guide light from the image generator toward the folding surface and to form an aperture stop for the optical image relay at the folding surface; a doublet positioned between the first plano-aspheric lens and the image generator; a meniscus singlet lens positioned between the doublet and the image generator; and a concave-plano field lens positioned between the meniscus singlet and the image generator; wherein the optical image relay, the partially transmissive mirror, and the beam splitter are configured to form an exit pupil for viewing the 2D image superimposed on a portion of a visible object scene. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein the wearable display apparatus is configured to form a binocular, 3-dimensional image. ### Claim 3 (depends on 1) The apparatus of claim 1 wherein the optical image relay further comprises a second plano-aspheric lens in optical contact against the prism output surface and configured to direct the light to the curved focal surface. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the concave-plano field lens includes sides truncated along a vertical direction. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the doublet includes a concave/convex flint glass lens cemented to a crown glass lens. ### Claim 6 (depends on 1) The apparatus of claim 1 having a field of view (FOV) wherein a ratio of horizontal:vertical FOV dimensions equals or exceeds 1.5 and wherein the horizontal FOV equals or exceeds 50 degrees, and wherein the optical path is folded within the prism so that a portion of the system optical axis between the image generator and the prism is parallel to a line between left and right pupils of a viewer. ### Claim 7 (depends on 1) The apparatus of claim 1 wherein the partially transmissive curved reflective surface is conic. ### Claim 8 (depends on 1) The apparatus of claim 1 wherein the partially transmissive curved reflective surface is spherical. ### Claim 9 (depends on 1) The apparatus of claim 1 wherein the beam splitter is a polarization beam splitter. ### Claim 10 (depends on 1) The apparatus of claim 1 wherein the beam splitter is a wire grid polarization beam splitter. ### Claim 11 (depends on 1) The apparatus of claim 1 further comprising a quarter wave plate in the path of light between the polarization beam splitter and the curved mirror. ### Claim 12 (depends on 11) The apparatus of claim 11 wherein the quarter wave plate is cylindrically curved. ### Claim 13 (depends on 1) The apparatus of claim 1 wherein the image generator is an electroluminescent display that is disposed to direct an image-bearing light beam in a direction parallel to a line between left and right pupils of a viewer. ### Claim 14 (depends on 1) The apparatus of claim 1 further comprising a complementary facing prism and an eye-tracking sensor, wherein the folding surface is at least 10% transmissive to direct sensing light that reflects from an iris of the viewer through the folding surface and the complementary facing prism to the eye-tracking sensor. ### Claim 15 A wearable display apparatus having a left-eye optical system and a right-eye optical system, wherein each optical system defines a corresponding exit pupil for a viewer along a view axis and comprises: an electroluminescent image generator that is energizable to direct image-bearing light for a 2D image from an emissive surface; a curved reflective surface disposed along the view axis and partially transmissive, wherein the curved reflective surface defines a curved intermediate focal surface; a beam splitter disposed along the view axis and oriented to reflect light toward the curved reflective surface; and an optical image relay positioned between the electroluminescent image generator and the beam splitter, and configured to optically conjugate the formed 2D image from the image generator to the curved intermediate focal surface, the optical image relay including: a right-angle prism having a prism input surface facing toward the emissive surface of the image generator, a prism output surface facing toward the curved intermediate focal plane, and a folding surface extending from the prism input surface to the prism output surface, the folding surface configured to fold an optical path for light generated by the electroluminescent image generator towards the beam splitter, wherein an aperture stop for the relay lies within the prism near the folding surface; a first plano-aspheric lens in optical contact against the prism input surface and configured to guide the image-bearing light from the electroluminescent image generator toward the folding surface; a second plano-aspheric lens in optical contact against the prism output surface and configured to direct the light from the folding surface toward the curved intermediate focal surface; a doublet positioned between the first plano-aspheric lens and the electroluminescent image generator; a meniscus singlet lens positioned between the doublet and the electroluminescent image generator; and a concave-plano field lens positioned between the meniscus singlet and the electroluminescent image generator; wherein the optical image relay, the curved reflective surface, and the beam splitter are configured to form the exit pupil for viewing the generated 2D image superimposed on a portion of a visible object scene. ### Claim 16 (depends on 15) The apparatus of claim 15 further comprising a cylindrically curved quarter wave plate in the path of light between the beam splitter and the curved reflective surface. ### Claim 17 (depends on 15) The apparatus of claim 15 further comprising a complementary facing prism and an eye-tracking sensor, wherein the folding surface is partially transmissive to direct sensing light that reflects from an iris of the viewer through the folding surface and the complementary facing prism to the eye-tracking sensor. ### Claim 18 A method for forming an image for a viewer of a wearable display apparatus, the method comprising: providing an image generator that forms a 2D image; providing a partially transmissive curved mirror having a curved focal surface and a partially transmissive curved reflective surface; providing a beam splitter disposed to reflect light toward the partially transmissive mirror, wherein the curved focal surface is defined in a space between the partially transmissive curved reflective surface and the beam splitter; providing an optical image relay positioned between the image generator and the beam splitter, and configured to conjugate the formed 2D image from the image generator to the curved focal surface of the partially transmissive mirror, the optical image relay including: a right-angle prism having a prism input surface, a prism output surface, and a folding surface extending from the prism input surface to the prism output surface; a first plano-aspheric lens in optical contact against the prism input surface and configured to guide light from the image generator toward the folding surface and to form an aperture stop for the optical image relay at the folding surface; a doublet positioned between the first plano-aspheric lens and the image generator; a meniscus singlet lens positioned between the doublet and the image generator; and a concave-plano field lens positioned between the meniscus singlet and the image generator; forming an eyebox for display, from an intermediate image formed on the curved focal surface, by disposing the beam splitter to reflect light from the optical image relay toward the partially transmissive curved mirror; configuring the optical image relay to: direct modulated light from the image generator along an optical path; focus the light through the aperture stop formed at the folding surface of the right-angle prism; and fold the optical path to direct the modulated light to focus along the curved focal surface; and providing one or more signals to the image generator for providing modulated light output, wherein the optical image relay, the partially transmissive curved mirror, and the beam splitter are configured to form an exit pupil within the eyebox for viewing the 2D image superimposed on a portion of an object scene that is visible through the partially transmissive curved mirror. ### Claim 19 (depends on 18) The method of claim 18 further comprising: providing a complementary facing prism and an eye-tracking sensor; and providing the folding surface of the right-angle prism including a partially transmissive surface; and obtaining an image of the viewer's iris from light transmitted through the folding surface and the complementary facing prism to the eye-tracking sensor. ### Claim 20 (depends on 18) The method of claim 18 further comprising adjusting a focal surface position for the modulated light using a piezoelectric actuator.