# US 12,000,781 B2 · Multispectral LiDAR transceiver > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,000,781 B2 - Document ID: US12000781B2 - Status: Granted - Kind: B2 - Application number: 16/981,795 - Filed: 2019-03-19 - Published: 2021-02-11 - Granted: 2024-06-04 - Earliest claimed: 2018-03-19 - Assignees: Iridesense - Applicants: Iridesense - Inventors: Scott Buchter - Web page: https://patentgrep.com/patent/US12000781B2 ## CPC - G01N 21/21: Polarisation-affecting properties (G01N21/19 takes precedence) - G01N 21/55: Specular reflectivity - B60W 30/0956: {the prediction being responsive to traffic or environmental parameters} - B60W 60/001: {Planning or execution of driving tasks} - G01S 7/4802: {using analysis of echo signal for target characterisation; Target signature; Target cross-section} - G01S 7/4814: {of transmitters alone} - G01S 7/4816: {of receivers alone} - G01S 7/4817: {relating to scanning} - G01S 17/08: for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) - G01S 17/50: Systems of measurement based on relative movement of target - G01S 17/89: for mapping or imaging - G01S 17/894: Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar - G06T 17/00: Three-dimensional [3D] modelling for computer graphics - G06T 19/20: Editing of three-dimensional [3D] images, e.g. changing shapes or colours, aligning objects or positioning parts - G06V 20/58: Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads - H04N 1/00827: {Arrangements for reading an image from an unusual original, e.g. 3-dimensional objects} - B60W 2420/408: Radar; Laser, e.g. lidar - B60W 2420/54: Audio sensitive means, e.g. ultrasound - G01N 2021/217: {Measuring depolarisation or comparing polarised and depolarised parts of light} - G01N 2021/4792: {Polarisation of scatter light} - G01N 2201/06113: Coherent sources; lasers - G01S 17/86: Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders - G01S 17/87: Combinations of systems using electromagnetic waves other than radio waves - G06T 2210/56: Particle system, point based geometry or rendering - G06T 2219/2004: Aligning objects, relative positioning of parts - G06V 2201/07: Target detection - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A scanning device for laser detection and ranging (LiDAR), the scanning device includes, arranged in optical free space: an optical input for receiving a pulsed broadband laser beam having a linear polarization; a separating unit configured for transmitting the laser beam along a scanning optical path while changing the polarization into a circular one; a wavelength selection unit; and a scanning unit. The separating unit is configured for deviating the reflections (4) on a broadband detector while changing the orthogonal circular polarization into an orthogonal linear polarization compared to the linear polarization of the laser beam. The broadband detector is configured to receive the deviated reflections, and to detect a time-of-flight and an optical power of the light reflection. ## Claims ### Claim 1 A scanning device for laser detection and ranging (LiDAR), the scanning device comprising, arranged in optical free space: an optical input for receiving a pulsed broadband laser beam, the pulsed broadband laser beam having a linear polarization; a separating unit configured for transmitting the pulsed broadband laser beam along a scanning optical path while changing the linear polarization into a circular polarization; a wavelength selection unit configured for: receiving the pulsed broadband laser beam from the separating unit, filtering the pulsed broadband laser beam in order to get a filtered laser beam having a current wavelength that can be selected among a plurality of selectable wavelengths, and deflecting the filtered laser beam on a scanning unit along the scanning optical path to result in a deflected filtered laser beam, the scanning unit being configured: to steer the deflected filtered laser beam along a plurality of current local directions inside a predefined solid angle, to receive reflections of the filtered laser beam, the reflections coming back from surroundings, the reflections having an orthogonal circular polarization compared to the circular polarization of the pulsed broadband laser beam, and to transmit back the received reflections to the separating unit through the wavelength selection unit along a detection optical path, wherein the detection optical path and the scanning optical path have a same light path through the wavelength selection unit and the scanning unit, but opposite direction of light propagation, wherein the separating unit is further configured for deviating the reflections on a broadband detector while changing the orthogonal circular polarization into an orthogonal linear polarization compared to the linear polarization of the pulsed broadband laser beam, the broadband detector being configured to receive deviated reflections deviated by the separating unit, and to detect a time-of-flight and an optical power of the deviated reflections. ### Claim 2 (depends on 1) The scanning device according to claim 1, wherein the broadband detector is a single, non-tunable, detector. ### Claim 3 (depends on 1) The scanning device according to claim 1, wherein the separating unit comprises: a polarizing beam splitter configured to perform said transmitting of the pulsed broadband laser beam along the scanning optical path and to deviate the reflections along the detection optical path, and an optical component being disposed on a same light path between the polarizing beam splitter and the wavelength selection unit and being configured to convert a linear polarization into a circular polarization along the scanning optical path and to convert an orthogonal circular polarization into an orthogonal linear polarization along the detection optical path. ### Claim 4 (depends on 1) The scanning device according to claim 1, wherein the reflections are deviated at a predefined angle to give the deviated reflections, such that the deviated reflections reach the broadband detector. ### Claim 5 (depends on 1) The scanning device according to claim 1, wherein the wavelength selection unit comprises a grating for diffracting the pulsed broadband laser beam, and a minor, one of the grating and the mirror being orientable, whose orientation is adjustable in order to select a 1st order of a selected wavelength diffracted beam. ### Claim 6 (depends on 5) The scanning device according to claim 5, wherein the selected wavelength diffracted beam has a FWHM up to 30 nm. ### Claim 7 (depends on 5) The scanning device according to claim 5, wherein the selected wavelength diffracted beam has a FWHM in the range of 10 nm to 20 nm. ### Claim 8 (depends on 1) The scanning device according to claim 1, wherein the plurality of selectable wavelengths are spaced with each other by at least 10 nm. ### Claim 9 (depends on 1) The scanning device according to claim 1, wherein the plurality of selectable wavelengths are spaced with each other by 15 nm. ### Claim 10 (depends on 1) The scanning device according to claim 1, wherein the plurality of selectable wavelengths are spaced with each other by 20 nm. ### Claim 11 (depends on 1) The scanning device according to claim 1, wherein the plurality of selectable wavelengths are in the range of 900 nm to 1700 nm. ### Claim 12 (depends on 1) The scanning device according to claim 1, wherein the plurality of selectable wavelengths comprises at least three wavelengths. ### Claim 13 (depends on 1) The scanning device according to claim 1, wherein the plurality of selectable wavelengths comprises at least five wavelengths. ### Claim 14 (depends on 1) The scanning device according to claim 1 wherein the plurality of selectable wavelengths comprises at least ten wavelengths. ### Claim 15 (depends on 1) The scanning device according to claim 1, further comprising a broadband laser source configured to send the pulsed broadband laser beam to the separating unit through the optical input. ### Claim 16 (depends on 1) The scanning device according to claim 1, wherein the pulsed broadband laser beam has a frequency above 300 kHz. ### Claim 17 (depends on 1) The scanning device according to claim 1, wherein the predefined solid angle has a horizontal angular dimension in the range of 45 degrees to 360 degrees and a vertical angular dimension in the range of 10 degrees to 180 degrees. ### Claim 18 (depends on 1) The scanning device according to claim 1, wherein the predefined solid angle has a horizontal angular dimension in the range of 90 degrees to 180 degrees and a vertical angular dimension in the range of 20 degrees to 90 degrees. ### Claim 19 (depends on 1) The scanning device according to claim 1, wherein the predefined solid angle has a horizontal angular dimension of 120 degrees and a vertical angular dimension of 30 degrees. ### Claim 20 (depends on 1) The scanning device according to claim 1, further comprising: a memory configured to store a set of wavelength values corresponding to the plurality of selectable wavelengths, the scanning device further comprising: processing means configured for the scanning device to successively select a wavelength current value in the set of wavelength values at a wavelength selection rate, wherein the wavelength selection rate is higher than 3 Hz, and controlling means configured to control the wavelength selection unit in order to tune the wavelength selection unit to a wavelength current value. ### Claim 21 (depends on 20) The scanning device according to claim 20, further comprising: driving means configured to control the scanning unit for steering said deflected filtered laser beam along said plurality of current local directions inside said predefined solid angle, and the scanning device being further configured to record in the memory an optical power and a time-of-flight in relation with the current wavelength value and coordinates of a current local direction. ### Claim 22 (depends on 17, 21) The scanning device according to claim 17 and according to claim 21, wherein the scanning unit is configured for: vertically scanning the entire vertical angular dimension of the solid angle, the vertical scanning being repeatedly performed at a vertical scan frequency, and horizontally scanning the entire horizontal angular dimension of the solid angle, the horizontal scanning being repeatedly performed at a horizontal scan frequency. ### Claim 23 (depends on 22) The scanning device according to claim 22, wherein a wavelength selection rate is lower than the horizontal scan frequency and the vertical scan frequency. ### Claim 24 (depends on 22) The scanning device according to claim 22, wherein the horizontal scan frequency is at least 10 times higher than a wavelength rate.