# US 12,007,569 B2 · Compact catadioptric projector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,569 B2 - Document ID: US12007569B2 - Status: Granted - Kind: B2 - Application number: 18/139,736 - Filed: 2023-04-26 - Published: 2023-08-24 - Granted: 2024-06-11 - Earliest claimed: 2021-09-13 - Assignees: Snap Inc. - Applicants: Snap Inc. - Inventors: Miller Schuck; Robert Matthew Bates - Web page: https://patentgrep.com/patent/US12007569B2 ## CPC - G02B 27/0172: {characterised by optical features} - G02B 5/3083: {Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001)} - G02B 27/0093: {with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking} - G02B 27/0176: {characterised by mechanical features} - G02B 27/283: {used for beam splitting or combining} - G02C 11/10: {Electronic devices other than hearing aids} - G06F 3/011: {Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00)} - G09G 3/002: {to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT} - H04N 23/11: for generating image signals from visible and infrared light wavelengths - H04N 23/50: Constructional details - H04N 23/90: Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums - G02B 2027/0134: {of stereoscopic type} - G02B 2027/0138: {comprising image capture systems, e.g. camera} - G02B 2027/014: {comprising information/image processing systems} - 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} - G06F 3/012: {Head tracking input arrangements} - G06F 3/013: {Eye tracking input arrangements (G06F3/015 takes precedence)} - H04N 13/239: using two two-dimensional [2D] image sensors having a relative position equal to or related to the interocular distance (H04N13/243 takes precedence) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G02C: SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES (trial frames for testing the eyes A61B3/04; goggles or eyeshields not having the same features as spectacles A61F9/00) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A compact projector for eyewear including a refractive lens to achromatize an image and to reduce the size of the projector. The compact projector includes two total internal reflection (TIR) prisms, a polarizing beamsplitter, a quarter-wave plate, and the refractive lens combining refractive and reflective power, referred to as catadioptric. In one example, a light source generates light that is directed through a collector, into a first TIR prism, to the polarizing beamsplitter, and to a display panel. The display panel modulates the light and creates an image. The image is directed through the beamsplitter, into a second TIR prism, through a quarter-wave plate, and then to the refractive lens. The refractive lens reflects the image back into the second TIR prism, and which image then exits to a waveguide. In a second example, the display generates an illuminated image which is then processed as in the first example. ## Claims ### Claim 1 A prism, comprising: a first total internal reflection (TIR) prism configured to route light from a light source; a second TIR prism coupled to the first TIR prism at an interface and configured to route the light from the first TIR prism to a display; a polarizing beamsplitter disposed at the interface between the first and second TIR prisms; and a quarter-wave plate configured to receive the light from the second TIR prism, wherein the second TIR prism is configured to direct reflected light from the quarter-wave plate to an output. ### Claim 2 (depends on 1) The prism of claim 1, further comprising a refractive lens configured to reflect the light passing through the quarter-wave plate back into the second TIR prism. ### Claim 3 (depends on 2) The prism of claim 2, wherein the refractive lens comprises a first lens and a minor configured to achromatize an image. ### Claim 4 (depends on 2) The prism of claim 2, wherein the refractive lens is configured to form a Fourier transform of the light. ### Claim 5 (depends on 1) The prism of claim 1, wherein the polarizing beamsplitter is configured to reflect and polarize the light. ### Claim 6 (depends on 5) The prism of claim 5, wherein the polarizing beamsplitter is configured to reflect light of one linear polarization and transmit light of an orthogonal linear polarization. ### Claim 7 (depends on 1) The prism of claim 1, wherein the polarizing beamsplitter comprises of two layers sandwiching a linear polarizer. ### Claim 8 (depends on 1) The prism of claim 1 further comprising a collector disposed between the light source and the first TIR prism. ### Claim 9 (depends on 1) The prism of claim 1, further comprising a polarizer coupled to the second TIR prism output. ### Claim 10 A prism, comprising: a first total internal reflection (TIR) prism configured to route an image; a second TIR prism coupled to the first TIR prism at an interface and configured to route the image from the first TIR prism; a polarizing beamsplitter disposed at the interface between the first and second TIR prisms; and a quarter-wave plate configured to receive the image from the second TIR prism. ### Claim 11 A method of use of a prism, comprising: routing light from a light source using a first total internal reflection (TIR) prism; routing the light from the first TIR prism using a second TIR prism coupled to the first TIR prism at an interface, wherein a polarizing beamsplitter is disposed at the interface between the first and second TIR prisms and polarizes the light; receiving the light from the second TIR prism at a quarter-wave plate; and reflecting the light passing through the quarter-wave plate back into the second TIR prism. ### Claim 12 (depends on 11) The method of claim 11, further comprising directing the reflected light with the second TIR prism from a lens to an output that is configured to couple to a waveguide. ### Claim 13 (depends on 12) The method of claim 12, wherein the lens comprises a refractive lens including a first lens and a mirror achromatizing an image. ### Claim 14 (depends on 13) The method of claim 13, wherein the refractive lens forms a Fourier transform of the light. ### Claim 15 (depends on 13) The method of claim 13, wherein the refractive lens comprises a crown glass and a flint glass. ### Claim 16 (depends on 11) The method of claim 11, wherein the polarizing beamsplitter reflects and polarizes the light. ### Claim 17 (depends on 16) The method of claim 16, wherein the polarizing beamsplitter reflects light of one linear polarization and transmits light of an orthogonal linear polarization. ### Claim 18 (depends on 11) The method of claim 11, wherein the polarizing beamsplitter comprises of two layers sandwiching a linear polarizer. ### Claim 19 (depends on 11) The method of claim 11 further comprising a collector disposed between the light source and the first TIR prism. ### Claim 20 (depends on 11) The method of claim 11, further comprising a polarizer coupled to an output of the second TIR prism.