# US 12,007,219 B2 · Laser triangulation apparatus and calibration method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,219 B2 - Document ID: US12007219B2 - Status: Granted - Kind: B2 - Application number: 17/282,141 - Filed: 2019-09-09 - Published: 2021-11-18 - Granted: 2024-06-11 - Earliest claimed: 2018-10-02 - Assignees: ASML Netherlands B.V. - Applicants: ASML Netherlands B.V. - Inventors: Erwin Van Dorp - Web page: https://patentgrep.com/patent/US12007219B2 ## CPC - G01B 11/0608: {Height gauges} - G01B 21/042: {Calibration or calibration artifacts (G01B3/30, G01B9/02072 take precedence)} - G01C 3/08: Use of electric radiation detectors - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) ## Abstract The invention provides an apparatus configured for determining a distance of the apparatus to an object according to the principle of triangulation. The apparatus comprises a transmissive device with a predefined distance between a first surface and a second surface of the transmissive device, and a detector that is configured to receive at least a portion of a radiation beam after interaction with the transmissive device and the object. The first surface is arranged to reflect a first part of the radiation beam, and the second surface is arranged to reflect a second part of the radiation beam. The predefined distance is used for determining the distance of the apparatus to the object. ## Claims ### Claim 1 An apparatus for determining a distance of the apparatus to an object comprising: a transmissive device with at least one tunable reflective surface comprising a switchable mirror, the transmissive device having a predefined distance between a first surface and a second surface of the device, wherein: the first surface is arranged to reflect a first part of a radiation beam, and the second surface is arranged to reflect a second part of the radiation beam, a detector configured to receive at least a portion of: the first part of the radiation beam on a first location on the detector, the second part of the radiation beam on a second location on the detector, and the radiation beam after interaction with the transmissive device and with the object on a third location on the detector, and a processor configured to receive a signal from the detector to determine the distance of the apparatus to the object based on a spatial distance between the first location and the second location, and at least one of: a spatial distance between the first location and the third location, and a spatial distance between the second location and the third location. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein: the transmissive device is a transmissive plate, the first surface is on one side of the transmissive plate, and the second surface is on an opposite side of the transmissive plate. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the transmissive device is plane-parallel. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein the transmissive device comprises at least: a first transmissive plate with a first predefined thickness, a second transmissive plate with a second predefined thickness, or a plurality of transmissive plates, each with a predefined thickness. ### Claim 5 (depends on 2) The apparatus of claim 2, wherein the transmissive device is arranged not to intersect the radiation beam reflected from the object. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the transmissive device comprises a recess configured to pass the radiation beam reflected from the object without interaction with the transmissive device. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein: the radiation beam comprises at least a first and a second radiation beam, and the first and second radiation beams intersect the transmissive device geometrically different. ### Claim 8 (depends on 1) The apparatus of claim 1, further comprising a temperature sensor. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the processor is configured to control at least one of an intensity of the radiation beam or a wavelength of the radiation beam. ### Claim 10 (depends on 1) A lithographic apparatus comprising at least one apparatus of claim 1. ### Claim 11 (depends on 1) A metrology apparatus comprising at least one apparatus of claim 1. ### Claim 12 (depends on 1) A camera system comprising at least one apparatus of claim 1. ### Claim 13 A method for determining a distance of an apparatus to an object, the method comprising: providing a beam of radiation; projecting the beam of radiation onto a transmissive device with at least one tunable reflective surface comprising a switchable mirror, the transmissive device being arranged in the apparatus; irradiating the object with at least a portion of the beam of radiation transmitted through the transmissive device; receiving at least a portion of a first part of the beam of radiation reflected by a first surface of the transmissive device on a first location on a detector; receiving at least a portion of a second part of the beam of radiation reflected by a second surface of the transmissive device on a second location on the detector; receiving at least a portion of the beam of radiation after interaction with the transmissive device and with the object on a third location on the detector; and deriving the distance of the apparatus to the object based on a spatial distance between the first location and the second location, and at least one of: a spatial distance between the first location and the third location, and a spatial distance between the second location and the third location. ### Claim 14 (depends on 13) The method of claim 13, wherein the transmissive device has a predefined distance between the first surface and the second surface of the transmissive device. ### Claim 15 (depends on 13) The method of claim 13, wherein: the transmissive device is a transmissive plate, the first surface is on one side of the transmissive plate, and the second surface is on an opposite side of the transmissive plate. ### Claim 16 (depends on 13) The method of claim 13, wherein the transmissive device is plane-parallel. ### Claim 17 (depends on 13) The method of claim 13, wherein the transmissive device comprises at least: a first transmissive plate with a first predefined thickness, a second transmissive plate with a second predefined thickness, or a plurality of transmissive plates, each with a predefined thickness. ### Claim 18 (depends on 13) The method of claim 13, wherein the transmissive device is arranged not to intersect the radiation beam reflected from the object.