# US 11,079,478 B2 · Optoelectronic sensor and method for measuring a distance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,478 B2 - Document ID: US11079478B2 - Status: Granted - Kind: B2 - Application number: 16/031,625 - Filed: 2018-07-10 - Published: 2019-01-17 - Granted: 2021-08-03 - Earliest claimed: 2017-07-11 - Assignees: Fondazione Bruno Kessler - Applicants: Fondanzione Bruno Kessler - Inventors: Daniele Perenzoni; David Stoppa; Leonardo Gasparini; Matteo Perenzoni; Nicola Massari; Ulrich Zwölfer; Kai Waslowski; Alexander Bohli; Michael Albert; Friedhelm Wiethege - Web page: https://patentgrep.com/patent/US11079478B2 ## CPC - G01S 7/4865: Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) - G01C 3/08: Use of electric radiation detectors - G01C 15/002: {Active optical surveying means (optical plumbing G01C15/105)} - G01S 7/4808: {Evaluating distance, position or velocity data} - G01S 7/4861: Circuits for detection, sampling, integration or read-out - G01S 7/4863: Detector arrays, e.g. charge-transfer gates - G01S 7/4868: {Controlling received signal intensity or exposure of sensor} - G01S 7/4876: {by removing unwanted signals (G01S7/495 takes precedence)} - G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) - G01S 17/04: Systems determining the presence of a target - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - 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 An optoelectronic sensor (10) for measuring a distance of an object (18) in accordance with a time of flight principle comprises a light transmitter (12) for transmitting a light signal (14), a light receiver (22) for receiving the light signal (20) after reflection or remission by the object (18), the light receiver (22) having a first plurality of pixel elements (24, 24a) each configured as an avalanche photo diode element biased with a bias voltage greater than a breakdown voltage and thus operated in a Geiger mode in order to trigger an avalanche event upon light reception, a distance measuring unit (34) having a second plurality of time of flight measuring units (34a) connected to pixel elements (24a) for determining a time of flight between transmission and reception of a light signal, the second plurality being less than the first plurality, switching means (32, 32a) for connecting selected pixel elements (24a) to time of flight measuring units (34a) in a one-to-one fashion, and a pixel selection unit (28, 30) for determining pixel elements (24a) to be connected by the switching means (32, 32a) based on an intensity measurement. ## Claims ### Claim 1 An optoelectronic sensor (10) for measuring a distance of an object (18) in accordance with a time of flight principle, the sensor (10) comprising a light transmitter (12) for transmitting a light signal (14), a light receiver (22) for receiving the light signal (20) after reflection or remission by the object (18), the light receiver (22) having a first plurality of pixel elements (24, 24a) each configured as an avalanche photo diode element biased with a bias voltage greater than a breakthrough voltage and thus operated in a Geiger mode in order to trigger an avalanche event upon light reception and a distance measuring unit (34) having a second plurality of time of flight measuring units (34a) connected to pixel elements (24a) for determining a time of flight between transmission and reception of a light signal, the second plurality being less than the first plurality, switching means (32, 32a) for connecting only a selected portion of the pixel elements (24a) to time of flight measuring units (34a) in a one-to-one fashion, so that only some of the pixel elements (24a) are used for time of flight measurement, and a pixel selection unit (28, 30) for determining pixel elements (24a) to be connected by the switching means (32, 32a) based on an intensity measurement, thus excluding pixel elements actually only contributing ambient light or dark count events from the distance measurement. ### Claim 2 (depends on 1) The sensor (10) according to claim 1, wherein the time of flight measuring units (34a) each comprise a Time-to-Digital Converter (TDC). ### Claim 3 (depends on 1) The sensor (10) according to claim 1, wherein the switching means (32) comprise a matrix of programmable interconnections (32a). ### Claim 4 (depends on 1) The sensor (10) according to claim 1, wherein the pixel selection unit (28) comprises a plurality of counters (28a), each counter (28a) being connected with at least one pixel element (24) for counting avalanche events of the connected pixel elements (24). ### Claim 5 (depends on 4) The sensor (10) according to claim 4, wherein the switching means (32, 32a) connect pixel elements (24a) to time of flight measuring units (34a) according to the count of avalanche events, in particular those pixel elements (24a) having the largest count and/or having a count exceeding a threshold. ### Claim 6 (depends on 4) The sensor (10) according to claim 4, wherein the counters (28) are column counters or row counters connected to a column or a row of pixel elements (24). ### Claim 7 (depends on 6) The sensor (10) according to claim 6, wherein a column counter (28a) only counts events from active rows being a subset of all rows, or wherein a row counter only counts events from active columns being a subset of all columns. ### Claim 8 (depends on 4) The sensor (10) according to claim 4, wherein the pixel elements (24) each comprise a time of flight measurement output (48) and a counter output (46). ### Claim 9 (depends on 1) The sensor (10) according claim 1, wherein the pixel selection unit (28, 30) is configured to determine pixel elements (24a) to be connected by the switching means (32, 32a) during manufacturing or teach-in. ### Claim 10 (depends on 1) The sensor (10) according to claim 1, wherein the pixel elements (24) each comprise deactivation means (40). ### Claim 11 (depends on 1) The sensor (10) according to claim 1, further comprising histogram evaluation means (36) for statistically evaluating a plurality of times of flight generated by the time of flight measuring units (34a) of the distance measuring unit (34). ### Claim 12 (depends on 1) The sensor (10) according to claim 1, wherein the sensor (10) is a switching sensor switching its output state in dependence on whether an object (18) has been detected within a specified distance range. ### Claim 13 A method for measuring a distance of an object (18) in accordance with a time of flight principle, the method comprising the steps of transmitting a light signal (14); receiving the light signal (22) after reflection or remission by the object (18) in a light receiver (22) having a first plurality of pixel elements (24, 24a) each configured as an avalanche photo diode element biased with a bias voltage greater than a breakthrough voltage and thus operated in a Geiger mode in order to trigger an avalanche event upon light reception, and determining a time of flight between transmission and reception of a light signal (14, 22) by means of a second plurality of time of flight measuring units (34a) connected to pixel elements (24a), the second plurality being less than the first plurality, connecting only a selected portion of the pixel elements (24a) to time of flight measuring units (34a) in a one-to-one fashion, so that only some of the pixel elements (24a) are used for time of flight measurement, and selecting pixel elements (24a) to be connected based on an intensity measurement, thus excluding pixel elements actually only contributing ambient light or dark count events from the distance measurement. ### Claim 14 An optoelectronic sensor (10) for measuring a distance of an object (18) in accordance with a time of flight principle, the sensor (10) comprising a light transmitter (12) for transmitting a light signal (14), a light receiver (22) for receiving the light signal (20) after reflection or remission by the object (18), the light receiver (22) having a first plurality of pixel elements (24, 24a) each configured as an avalanche photo diode element biased with a bias voltage greater than a breakthrough voltage and thus operated in a Geiger mode in order to trigger an avalanche event upon light reception and a distance measuring unit (34) having a second plurality of time of flight measuring units (34a) connected to pixel elements (24a) for determining a time of flight between transmission and reception of a light signal, the second plurality being less than the first plurality, switching means (32, 32a) for connecting only a selected portion of the pixel elements (24a) to time of flight measuring units (34a) in a one-to-one fashion, so that only some of the pixel elements (24a) are used for time of flight measurement, and a pixel selection unit (28, 30) for determining pixel elements (24a) to be connected by the switching means (32, 32a) based on an intensity measurement, thus excluding pixel elements actually only contributing ambient light or dark count events from the distance measurement, wherein the switching means (32) comprise a matrix of programmable interconnections (32a), and wherein the pixel selection unit (28) comprises a plurality of counters (28a), each counter (28a) being connected with at least one pixel element (24) for counting avalanche events of the connected pixel elements (24). ### Claim 15 (depends on 14) The sensor (10) according to claim 14, wherein the switching means (32, 32a) connect pixel elements (24a) to time of flight measuring units (34a) according to the count of avalanche events, in particular those pixel elements (24a) having the largest count and/or having a count exceeding a threshold. ### Claim 16 (depends on 14) The sensor (10) according to claim 14, wherein the counters (28) are column counters or row counters connected to a column or a row of pixel elements (24). ### Claim 17 (depends on 16) The sensor (10) according to claim 16, wherein a column counter (28a) only counts events from active rows being a subset of all rows, or wherein a row counter only counts events from active columns being a subset of all columns.