# US 11,906,289 B2 · Triangulation-based optical profilometry system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,289 B2 - Document ID: US11906289B2 - Status: Granted - Kind: B2 - Application number: 17/612,466 - Filed: 2019-06-28 - Published: 2022-07-07 - Granted: 2024-02-20 - Earliest claimed: 2019-06-28 - Assignees: Institut National D'Optique - Applicants: Institut National D'Optique (Ino) - Inventors: Francois Martin - Web page: https://patentgrep.com/patent/US11906289B2 ## CPC - G01B 11/2518: {Projection by scanning of the object} - G01B 11/24: for measuring contours or curvatures - G01B 11/25: by projecting a pattern, e.g. {one or more lines,} moiré fringes on the object (G01B11/255 takes precedence {; image analysis for depth or shape recovery G06T7/50}) - H04N 23/55: Optical parts specially adapted for electronic image sensors; Mounting thereof - H04N 23/56: provided with illuminating means - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A triangulation-based optical profilometry system for scanning a three-dimensional sample surface located at a sample plane includes a projection system; an image sensor; a processing unit; an objective lens assembly for imaging onto the image sensor a luminous line formed on the sample plane, a first direction orthogonal to an optical axis and being defined parallel to an extent of the luminous line, a second direction being defined perpendicular to the first direction; and a diaphragm defining a non-circular aperture defined by a first dimension and a second dimension greater than the first dimension, the diaphragm being rotationally oriented such that the first dimension is aligned with the first direction and the second dimension is aligned with the second direction, the objective lens assembly being arranged to form an out-of-focus image of the luminous line on the image sensor. ## Claims ### Claim 1 A triangulation-based optical profilometry system for scanning a three-dimensional sample surface located at a sample plane of the system, the system comprising: a projection system for projecting a luminous line across the sample surface, the luminous line extending laterally across the sample plane; an image sensor for converting images of the luminous line, as projected on the sample plane, into electrical signals, the image sensor being a two-dimensional array of pixels; a processing unit communicatively connected to the image sensor for processing the electrical signals; an objective lens assembly for imaging the luminous line, as projected on the sample plane, onto the image sensor, the objective lens assembly defining an optical axis extending between the sample plane and the image sensor, a lateral direction orthogonal to the optical axis and being defined parallel to an extent of the luminous line as projected, a vertical direction being defined perpendicular to the lateral direction, the lateral and vertical directions defining a plane orthogonal to the optical axis; and a diaphragm disposed along the optical axis between the sample plane and the image sensor, the diaphragm defining a non-circular aperture therein, the aperture being defined by a first dimension and a second dimension perpendicular to the first dimension, the second dimension being greater than the first dimension, the diaphragm being rotationally oriented relative to the image sensor such that the first dimension is aligned with the lateral direction and the second dimension is aligned with the vertical direction, the objective lens assembly being arranged to form an out-of-focus image of the sample plane on the image sensor, the diaphragm, the objective lens assembly, and the image sensor being arranged such that an image of a given point along the luminous line, as projected onto the sample surface and collected by the image sensor during operation of the system, exhibits greater vertical defocus than lateral defocus, during operation of the system, the image of the given point of the luminous line extending over a greater number of pixels of the image sensor in the vertical direction than in the lateral direction. ### Claim 2 (depends on 1) The system of claim 1, wherein, during operation of the system, the image of the given point of the luminous line on the image sensor extends vertically over at least two pixels of the image sensor. ### Claim 3 (depends on 1) The system of claim 1, wherein the image sensor is disposed at a defocus position shifted along the optical axis away from an image plane of the sample plane as imaged by the objective lens assembly. ### Claim 4 (depends on 1) The system of claim 1, wherein the objective lens assembly includes a plurality of lenses. ### Claim 5 (depends on 1) The system of claim 1, wherein the diaphragm is disposed at an aperture stop of the objective lens assembly. ### Claim 6 (depends on 1) The system of claim 1, wherein the diaphragm is disposed at an entrance pupil of the objective lens assembly. ### Claim 7 (depends on 1) The system of claim 1, wherein the diaphragm is disposed at an exit pupil of the objective lens assembly. ### Claim 8 (depends on 1) The system of claim 1, wherein the second dimension of the aperture is about four times greater than the first dimension. ### Claim 9 (depends on 1) The system of claim 1, wherein a shape of the aperture is generally rectangular. ### Claim 10 (depends on 1) The system of claim 1, wherein a shape of the aperture is one of a geometric stadium, an oval, a rhombus, and a rounded-corner rectangle. ### Claim 11 (depends on 1) The system of claim 1, wherein the image sensor is one of: a charge-coupled device (CCD), a complementary metal-oxide-semiconductor (CMOS) device, and a N-type metal-oxide-semiconductor (NMOS) device. ### Claim 12 (depends on 1) The system of claim 1, wherein: a normal defined by the sample plane is skewed by a first angle (γ) relative to the optical axis; and a normal defined by the image sensor is skewed by a second angle (γ′) relative to the optical axis. ### Claim 13 (depends on 12) The system of claim 12, wherein the first angle (γ) and the second angle (γ′) are arranged in a Scheimpflug configuration, such that the second angle (γ′) is chosen relative to the first angle (γ) according to the relation: γ ′ = tan - 1 ⁡ [ S i S o ⁢ tan ⁡ ( γ ) ] , where Si is an image distance measured from the objective lens assembly to the image sensor and So is an object distance measured from the sample plane to the objective lens assembly. ### Claim 14 (depends on 1) The system of claim 1, wherein the projection system comprises: at least one illumination source; and a projection optical assembly for projecting light from the illumination source onto the sample plane in the form of a line. ### Claim 15 (depends on 14) The system of claim 14, wherein: the at least one illumination source is a laser source; and the luminous line is a laser line projected onto the sample plane.