# US 12,598,369 B2 · Surface topography measurement systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,598,369 B2 - Document ID: US12598369B2 - Status: Granted - Kind: B2 - Application number: 18/813,687 - Filed: 2024-08-23 - Published: 2025-06-19 - Granted: 2026-04-07 - Earliest claimed: 2017-03-06 - Assignees: GelSight, Inc. - Applicants: GelSight, Inc. - Inventors: Janos Rohaly; Edward H. Adelson - Web page: https://patentgrep.com/patent/US12598369B2 ## CPC - H04N 23/56: provided with illuminating means - G01B 11/24: for measuring contours or curvatures - G01B 11/303: {using photoelectric detection means} - G02B 7/022: {lens and mount having complementary engagement means, e.g. screw/thread} - H04N 23/55: Optical parts specially adapted for electronic image sensors; Mounting thereof - G01B 11/30: for measuring roughness or irregularity of surfaces - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A topographical measurement system uses an imaging cartridge formed of a rigid optical element and a clear, elastomeric sensing surface configured to capture high-resolution topographical data from a measurement surface. The imaging cartridge may be configured as a removable cartridge for the system so that the imaging cartridge, including the rigid optical element and elastomeric sensing surface can be removed and replaced as a single, integral component that is robust/stable over multiple uses, and easily user-replaceable as frequently as necessary or desired. The cartridge may also usefully incorporate a number of light shaping and other features to support optimal illumination and image capture. ## Claims ### Claim 1 A retrographic sensing device for making a contact measurement of a surface geometry of a specimen, the retrographic sensing device comprising: a camera; an illumination system; a cartridge including a substrate formed of a rigid, optically clear material, a clear layer having a first surface supported by the substrate and a second surface opposing the first surface, the clear layer formed of a pliable material, and a reflective coating for the second surface of the clear material opposing the substrate, wherein the cartridge includes at least one curved optical surface; and a housing shaped and sized to removably and replaceably receive the cartridge in a predetermined position and orientation with the illumination system positioned to illuminate one or more sides of the substrate and the camera positioned to view the reflective coating through the substrate and the clear layer. ### Claim 2 (depends on 1) The retrographic sensing device of claim 1, wherein the at least one curved optical surface includes one or more light shaping features in a sidewall around the substrate, the one or more light shaping features configured to control an illumination of the second surface through the sidewall. ### Claim 3 (depends on 2) The retrographic sensing device of claim 2, wherein the one or more light shaping features include an optical film or a micro-lens array. ### Claim 4 (depends on 1) The retrographic sensing device of claim 1, wherein the at least one curved optical surface includes a curved portion of the second surface. ### Claim 5 (depends on 4) The retrographic sensing device of claim 4, wherein the curved portion of the second surface is a convex curved surface. ### Claim 6 (depends on 1) The retrographic sensing device of claim 1, wherein the at least one curved optical surface includes a curved portion of the first surface. ### Claim 7 (depends on 1) The retrographic sensing device of claim 1, further comprising a mechanical key in the cartridge for enforcing the predetermined position and orientation of the cartridge relative to the camera and the illumination system when the cartridge is placed for use in the housing. ### Claim 8 (depends on 1) The retrographic sensing device of claim 1, further comprising a sidewall around an exterior of the substrate between a top surface and a bottom surface of the substrate, the sidewall including one or more light shaping features to control illumination of the second surface through the pliable material. ### Claim 9 (depends on 8) The retrographic sensing device of claim 8, wherein the one or more light shaping features includes a diffusing surface to diffuse point sources of light from the illumination system. ### Claim 10 (depends on 8) The retrographic sensing device of claim 8, wherein the one or more light shaping features include a neutral density filter with graduated attenuation to compensate for a distance from the sidewall to a location on the second surface. ### Claim 11 A device comprising: an optical element having an interior including a rigid, optically transparent material; a first surface of the optical element, the first surface including a region with an optically transparent surface for capturing images through the optical element; a second surface of the optical element opposing the first surface; a center axis of the optical element passing through the first surface and the second surface; and a layer of pliable, optically transparent material disposed on the second surface and attached to the second surface, a first side of the layer adjacent to the second surface of the optical element having a second index of refraction matched to a first index of refraction of the second surface, and a second side of the layer opposing the second surface of the optical element having an optical coating with a predetermined reflectance, wherein the second side of the layer is configured to conform to a target surface, wherein the pliable, optically transparent material includes at least one curved optical surface. ### Claim 12 (depends on 11) The device of claim 11, wherein the at least one curved optical surface includes a sidewall around an exterior of the optical element. ### Claim 13 (depends on 12) The device of claim 12, wherein the sidewall includes one or more light shaping features configured to control an illumination of the second side of the layer of pliable optically transparent material through the sidewall. ### Claim 14 (depends on 11) The device of claim 11, wherein the at least one curved optical surface includes a curved portion of the second side of the layer of pliable optically transparent material. ### Claim 15 (depends on 14) The device of claim 14, wherein the curved portion of the second side of the layer is a convex curved surface. ### Claim 16 (depends on 14) The device of claim 14, wherein the curved portion of the second side of the layer includes a convex surface extending away from the layer. ### Claim 17 (depends on 11) The device of claim 11, wherein the at least one curved optical surface includes a surface of the layer of optically transparent material extending away from the layer. ### Claim 18 (depends on 11) The device of claim 11, wherein the at least one curved optical surface includes a curved surface of the layer of optically transparent material. ### Claim 19 (depends on 11) The device of claim 11, further comprising a mechanical key for enforcing a predetermined position and orientation of the optical element within a fixture of an imaging system. ### Claim 20 (depends on 19) The device of claim 19, further comprising the imaging system, one or more light sources, and one or more mechanical features providing the fixture to retain the optical element in the predetermined position and orientation relative to a camera and the one or more light sources.