# US 2019/0171027 A1 · Optical projector with off-axis diffractive element > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0171027 A1 - Document ID: US20190171027A1 - Status: Published application - Kind: A1 - Application number: 15/832,682 - Filed: 2017-12-05 - Published: 2019-06-06 - Earliest claimed: 2017-12-05 - Assignees: K Laser Technology, Inc. - Applicants: K Laser Technology, Inc. - Inventors: Wai-Hon Lee - Web page: https://patentgrep.com/patent/US20190171027A1 ## 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 27/18: for optical projection, e.g. combination of mirror and condenser and objective {(photographic, cine and overhead projectors G03B21/00; photographic projection printing G03B27/32; photolithographic projectors G03F7/20; projection television H04N5/74; colour projection television H04N9/31)} - G02B 27/42: Diffraction optics {, i.e. systems including a diffractive element being designed for providing a diffractive effect}(G02B27/60 takes precedence) - G02B 27/4255: {for alignment or positioning purposes (optical displacement encoding scales G01D5/347)} - G06V 10/145: Illumination specially adapted for pattern recognition, e.g. using gratings - G06V 20/64: Three-dimensional [3D] objects - G06V 40/161: {Detection; Localisation; Normalisation} - G06V 40/166: {using acquisition arrangements} - G06V 2201/121: using special illumination - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING ## Abstract Apparatus for projecting a pattern includes a laser source, a collimating lens and a diffractive optical element (DOE) to diffract the collimated laser beam into a specific dot pattern for sensing the depth of a three dimensional (3D) surface. ## Claims ### Claim 1 (canceled) ### Claim 2 An apparatus comprising: a laser configured to produce a laser beam; a collimating lens mounted to intercept the laser beam and produce a collimated beam: a diffractive optical element (DOE) having an off-axis diffraction pattern and mounted to intercept the collimated beam and produce an off-axis diffracted beam pattern including an off-center 0th order beam; and a projection element mounted to intercept the off-axis diffracted beam pattern and project a portion of the pattern excluding the 0th order beam; wherein the projection element comprises: a reflective component mounted at a non-45 degree angle to the 0th order beam; and a block mounted to intercept the 0th order beam. ### Claim 3 (depends on 2) The apparatus of claim 2 wherein the block is mounted to intercept the 0th order beam before the reflective component. ### Claim 4 (depends on 2) The apparatus of claim 2 wherein the block is mounted to intercept the 0th order beam after the reflective component. ### Claim 5 (depends on 2) The apparatus of claim 2 wherein the DOE is integrated with the reflective component. ### Claim 6 (depends on 2) The apparatus of claim 2 wherein the projection component comprises a reflective component mounted to reflect a portion of the off-axis diffracted beam pattern but not reflect the 0th order beam. ### Claim 7 An apparatus comprising: a laser configured to produce a laser beam; a collimating lens mounted to intercept the laser beam and produce a collimated beam; a diffractive optical element (DOE) having an off-axis diffraction pattern and mounted to intercept the collimated beam and produce an off-axis diffracted beam pattern including an off-center 0th order beam; and a projection element mounted to intercept the off-axis diffracted beam pattern and project a portion of the pattern excluding the 0th order beam; wherein the projection component includes an aperture positioned to not pass the 0th order beam. ### Claim 8 (depends on 2) The apparatus of claim 2 wherein the laser is an edge emitting laser. ### Claim 9 (depends on 2) The apparatus of claim 2 wherein the laser is a vertical cavity surface emitting laser (VCSEL). ### Claim 10 An apparatus comprising: a laser configured to produce a laser beam; a collimating lens mounted to intercept the laser beam and produce a collimated beam: a diffractive optical element (DOE) having an off-axis diffraction pattern and mounted to intercept the collimated beam and produce an off-axis diffracted beam pattern including an off-center 0th order beam; and a projection element mounted to intercept the off-axis diffracted beam pattern and project a portion of the pattern excluding the 0th order beam; wherein the projection element comprises: a block mounted to intercept the 0th order beam, the block having a low reflective, light diffusing surface such that any reflected portion of the 0th order beam is less bright than a second order diffraction beam. ### Claim 11 (canceled) ### Claim 12 (depends on 2) The apparatus of claim 2 wherein the apparatus is mounted in a smartphone. ### Claim 13 (canceled) ### Claim 14 A method comprising: producing a laser beam; intercepting the laser beam and producing a collimated beam; intercepting the collimated beam and producing an off-axis diffracted beam pattern including an off-center 0th order beam; and intercepting the off-axis diffracted beam pattern and projecting a portion of the pattern excluding the 0th order beam wherein the projecting step comprises: reflecting a portion of the pattern excluding the 0th order beam using a non-45 degree angle to the 0th order beam; and blocking the 0th order beam. ### Claim 15 (depends on 14) The method of claim 14 wherein blocking the 0th order beam is done before reflecting a portion of the pattern excluding the 0th order beam. ### Claim 16 (depends on 14) The method of claim 14 wherein blocking the 0th order beam is done after reflecting a portion of the pattern excluding the 0th order beam. ### Claim 17 (depends on 14) The method of claim 14 wherein both producing an off-axis diffracted beam pattern and reflecting a portion of the pattern excluding the 0th order beam are done using an integrated reflective and diffractive optical element component. ### Claim 18 (depends on 14) The method of claim 14 further comprising: recording first positions of a plurality of elements of the off-axis diffraction pattern as reflected off a flat surface and detected by the a photodetector; recording second positions of a plurality of elements of the off-axis diffraction pattern as reflected of a non-flat object to be measured; determining the difference between the first and second positions for the plurality of elements of the off-axis diffraction pattern as reflected; and generating a map of the depth of the non-flat object at different points based on the difference between the first and second positions for the plurality of elements of the off-axis diffraction pattern as reflected. ### Claim 19 (depends on 14) The method of claim 14 wherein the laser is an edge emitting laser. ### Claim 20 (depends on 14) The method of claim 14 wherein the step of projecting a portion of the pattern excluding the 0th order beam uses a mirror.