# US 12,222,198 B2 · Optical measurement device and multiple mirror > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,198 B2 - Document ID: US12222198B2 - Status: Granted - Kind: B2 - Application number: 17/431,327 - Filed: 2020-02-12 - Published: 2022-02-17 - Granted: 2025-02-11 - Earliest claimed: 2019-02-14 - Assignees: Hochschule Trier - Applicants: Hochschule Trier - Inventors: Michael Schuth; Christopher Petry - Web page: https://patentgrep.com/patent/US12222198B2 ## CPC - G01B 11/2441: {using interferometry} - G02B 17/004: {Systems comprising a plurality of reflections between two or more surfaces, e.g. cells, resonators (multipass arrangements for optical cuvettes G01N21/031; laser resonators H01S3/05)} - G01B 9/02081: {simultaneous quadrature detection, e.g. by spatial phase shifting} - G01B 9/02098: Shearing interferometers - G02B 5/005: {Diaphragms (for cameras G03B9/02)} - G02B 26/001: {based on interference in an adjustable optical cavity (interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26)} - G02B 27/148: {including stacked surfaces having at least one double-pass partially reflecting surface} - G02B 27/283: {used for beam splitting or combining} - G02B 27/50: Optics for phase object visualisation - G01B 2290/70: Using polarization in the interferometer - 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 multiple mirror for multiplying a single incident wavefront of electromagnetic radiation into a plurality of outgoing wavefronts, including at least one first mirror, onto which the incident wavefront first falls, and a second mirror, on which the wavefront is last reflected, wherein the mirror planes are superimposed in the direction of movement of the first wavefront. The first mirror is partially transparent to the electromagnetic radiation and the second mirror is fully reflective. ## Claims ### Claim 1 A device for interferometric, optical measurement of a surface, comprising a coherent light source emitting an electromagnetic beam; two beam splitters; two diaphragms each located on a flat side of one of the two beam splitters; a multiple mirror with two distanced mirrors, comprising a first mirror to which the incoming beam hits first, and a second mirror at which the beam is reflected last, wherein the mirrors are superimposed in the direction of motion of the first wavefront and wherein the first mirror is partially transparent for the electromagnetic beam and the second mirror is fully reflective; and whereby the beam splitters and the multiple mirror are arranged in such a manner that the electromagnetic beam hits the first beam splitter, is directed from the first beam splitter to the multiple mirror and then hits the second beam splitter; wherein a diaphragm of the two diaphragms is arranged in the beam path between the two beam splitters in such a manner that the beam passes through the diaphragm; and wherein a mirror of the multiple mirror is tiltable compared to the other mirror in such a manner that the mirrors enclose an angle and that a wavefront hitting the multiple mirror is divided into two outgoing wavefronts that are phase-shifted with respect to each other. ### Claim 2 (depends on 1) The device according to claim 1, comprising a second multiple mirror, wherein the electromagnetic beam hits the first beam splitter, is divided by the first beam splitter in two partial beams with different propagation directions and each partial beam is directed to one of the multiple mirrors and then both partial beams meet the second beam splitter, wherein one diaphragm is arranged in each of the beam paths between the two beam splitters in such a manner that each partial beam passes through one of the diaphragms. ### Claim 3 (depends on 1) The device according to claim 1, wherein the mirrors of the multiple mirror are flat. ### Claim 4 (depends on 1) The device according to claim 1, wherein the first and/or second mirror of the multiple mirror are rotatable around a rotation axis. ### Claim 5 (depends on 4) The device according to claim 4, wherein the first and/or second mirror of the multiple mirror are mounted in a mounting-frame of the mirrors. ### Claim 6 (depends on 2) The device according to claim 2, wherein one multiple mirror has a mirror which is tiltable over the other mirror in the one multiple mirror and the other multiple mirror has a mirror which is rotatable against the other mirror in the other multiple mirror by a rotation axis. ### Claim 7 (depends on 1) The device according claim 1, wherein the first mirror polarizes the electromagnetic radiation. ### Claim 8 (depends on 7) The device according claim 7, wherein the first mirror reflects radiation of a certain polarization and transmit a different polarization. ### Claim 9 (depends on 1) The device according to claim 1, wherein a camera records the electro-magnetic beam reflected by the multiple mirror. ### Claim 10 (depends on 9) The device according to claim 9, wherein the camera is a color camera having a camera sensor configured to detect more than one wavelength of electromagnetic beams. ### Claim 11 (depends on 1) The device according to claim 1, wherein at least one diaphragm has an aperture. ### Claim 12 (depends on 11) The device according to claim 11, wherein the aperture comprises a polarization filter or a frequency filter that allows only certain wave-lengths to pass through the diaphragm. ### Claim 13 (depends on 1) The device according to claim 1, wherein at least one diaphragm has two apertures. ### Claim 14 (depends on 13) The device according to claim 13, wherein the two apertures each have a polarization filter, which are orthogonally aligned to each other. ### Claim 15 (depends on 1) The device according to claim 1, wherein one diaphragm is designed as a grating diaphragm with apertures. ### Claim 16 (depends on 15) The device according to claim 15, wherein the apertures have in two dimensions certain slit widths wherein the slit widths have the same dimensions. ### Claim 17 A device for interferometric, optical measurement of a surface, comprising a coherent light source emitting an electromagnetic beam; two beam splitters; two diaphragms; a single mirror; a multiple mirror with two distanced mirrors, comprising a first mirror to which the incoming beam hits first, and a second mirror at which the beam is reflected last, wherein the mirrors are superimposed in the direction of motion of the first wavefront and wherein the first mirror is partially transparent for the electromagnetic beam and the second mirror is fully reflective; whereby the beam splitters, the single mirror and the multiple mirror are arranged in such a manner that the electromagnetic beam hits the first beam splitter, is divided by the first beam splitter in two partial beams with different propagation directions; wherein the first of the two partial beams is directed to the multiple mirror and then hits the second beam splitter, and the second of the two partial beams is directed to the single mirror and then hits the second beam splitter; wherein one diaphragm is arranged in each of the beam paths of the partial beams between the two beam splitters in such a manner that each partial beam passes through one of the diaphragms; and wherein a mirror of the multiple mirror is tiltable compared to the other mirror in such a manner that the mirrors enclose an angle and that a wavefront hitting the multiple mirror is divided into two outgoing wavefronts that are phase-shifted with respect to each other. ### Claim 18 A device for interferometric, optical measurement of a surface, comprising a coherent light source emitting an electromagnetic beam; two beam splitters; two diaphragms; two multiple mirrors with two distanced mirrors, each comprising a first mirror to which the incoming beam hits first, and a second mirror at which the beam is reflected last, wherein the mirrors are superimposed in the direction of motion of the first wavefront and wherein the first mirror is partially transparent for the electromagnetic beam and the second mirror is fully reflective; and whereby the beam splitters and the multiple mirror are arranged in such a manner that the electromagnetic beam hits the first beam splitter, is divided by the first beam splitter in two partial beams with different propagation directions and each partial beam is directed to one of the multiple mirrors and then both partial beams meet the second beam splitter, wherein one diaphragm is arranged in each of the beam paths between the two beam splitters in such a manner that each partial beam passes through one of the diaphragms, and wherein a mirror of the multiple mirror is tiltable compared to the other mirror in such a manner that the mirrors enclose an angle and that a wavefront hitting the multiple mirror is divided into two outgoing wavefronts that are phase-shifted with respect to each other.