# US 11,079,218 B2 · Measuring distance using a laser processing system with optical amplifier for amplifying measuring beam or reflected part of measurement beam > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,218 B2 - Document ID: US11079218B2 - Status: Granted - Kind: B2 - Application number: 16/255,472 - Filed: 2019-01-23 - Published: 2019-07-25 - Granted: 2021-08-03 - Earliest claimed: 2018-01-24 - Assignees: Precitec GmbH & Co. KG - Applicants: Precitec GmbH & Co. KG - Inventors: Rüdiger Moser; Martin Schönleber - Web page: https://patentgrep.com/patent/US11079218B2 ## CPC - G01B 11/22: for measuring depth - B23K 26/032: {using optical means} - B23K 26/24: Seam welding - B23K 26/705: {Beam measuring devices} - G01B 9/02044: {Imaging in the frequency domain, e.g. by using a spectrometer} - G01B 9/02091: Tomographic interferometers, e.g. based on optical coherence - G02B 27/10: Beam splitting or combining systems (polarising systems G02B27/28; mixing and splitting light signals using optical waveguides G02B6/28; {beam shaping, e.g. changing the cross-sectional area, by dividing or superposing multiple light beams G02B27/0905}) - H01S 3/10023: {by functional association of additional optical elements, e.g. filters, gratings, reflectors} - A61B 5/0066: {Optical coherence imaging} - A61B 5/296: for electromyography [EMG] - A61B 5/6886: {Monitoring or controlling distance between sensor and tissue} - A61H 23/02: with electric or magnetic drive - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61H: PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY (electrotherapy, magnetotherapy, radiation therapy or ultrasound therapy A61N) ## Abstract The present disclosure concerns a device for distance measurement for a laser processing system. The device comprises a light source, which is configured to generate a primary beam for direction onto a workpiece, at least one detection device configured to record a secondary beam reflected from the workpiece, at least one optical amplifier configured to amplify the primary beam and/or the secondary beam, and an evaluation unit configured to evaluate interference between spectral components in the frequency domain. ## Claims ### Claim 1 A distance-measuring device for a laser processing system, comprising: a light source configured to generate a measuring beam for direction onto a workpiece; at least one detection device configured to detect a reflected part of the measuring beam reflected from the workpiece; a beam splitter configured to provide the measuring beam into an object arm and a reference arm; at least one circulator configured to direct the measuring beam from the light source into a common beam path between the beam splitter and the at least one circulator and to direct the reflected part of the measuring beam from the common beam path to the at least one detection device; and an optical amplifier arranged in the common beam path between the beam splitter and the at least one circulator, the common beam path transmitting the measuring beam from the circulator to the beam splitter for directing the measuring beam into the object arm and towards the workpiece and transmitting the reflected part of the measuring beam reflected from the workpiece to the at least one circulator for directing the reflected part of the measuring beam towards the at least one detection device, the optical amplifier configured to amplify the measuring beam before the measuring beam is directed onto the workpiece and to amplify the reflected part of the measuring beam before the reflected part is directed towards the at least one detection device. ### Claim 2 (depends on 1) The device in accordance with claim 1, wherein the light source comprises at least one superluminescent diode, or a supercontinuum source. ### Claim 3 (depends on 1) The device in accordance with claim 1, wherein the optical amplifier is a fibre amplifier, a semiconductor-based amplifier, a Raman amplifier, an optical parametric amplifier, a bi-directional amplifier, or a combination of these. ### Claim 4 (depends on 1) The device in accordance with claim 1, further comprising a splitting device for splitting the amplified measuring beam into a plurality of measuring beams, wherein the splitting device comprises at least one multi-core fibre, or one micro-lens arrangement. ### Claim 5 (depends on 1) The device in accordance with claim 1, wherein the at least one circulator comprises a first circulator and a second circulator, and wherein the optical amplifier is arranged between the first circulator and the second circulator. ### Claim 6 (depends on 5) The device in accordance with claim 5, wherein a first beam path for the measuring beam and a second beam path for the reflected part of the measuring beam are arranged between the first circulator and the second circulator. ### Claim 7 (depends on 1) The device in accordance with claim 1, wherein the device is configured to determine a depth of a keyhole during a laser welding process. ### Claim 8 (depends on 1) The device in accordance with claim 1, further comprising an evaluation device configured to evaluate interference between spectral components in the frequency domain. ### Claim 9 A laser processing system comprising: a laser processing head for provision of a processing beam, wherein the laser processing head is configured to direct the processing beam onto a processing region of a workpiece; and a distance-measuring device for a laser processing system, comprising: a light source configured to generate a measuring beam for direction onto a workpiece; at least one detection device configured to detect a reflected part of the measuring beam reflected from the workpiece; a beam splitter configured to provide the measuring beam into an object arm and a reference arm; at least one circulator configured to direct the measuring beam from the light source into a common beam path between the beam splitter and the at least one circulator and to direct the reflected part of the measuring beam from the common beam path to the at least one detection device an optical amplifier arranged in the common beam path between the beam splitter and the at least one circulator, the common beam path, the common beam path transmitting the measuring beam from the circulator to the beam splitter for directing the measuring beam into the object arm and towards the workpiece and transmitting the reflected part of the measuring beam reflected from the workpiece to the at least one circulator for directing the reflected part of the measuring beam towards the at least one detection device, the optical amplifier configured to amplify the measuring beam before the measuring beam is directed onto the workpiece and to amplify the reflected part of the measuring beam before the reflected part is directed towards the at least one detection device. ### Claim 10 (depends on 9) The laser processing system in accordance with claim 9, wherein the distance-measuring device further comprising an evaluation device configured to evaluate interference between spectral components in the frequency domain.