# US 2021/0239802 A1 · Optical detector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0239802 A1 - Document ID: US20210239802A1 - Status: Published application - Kind: A1 - Application number: 17/161,441 - Filed: 2021-01-28 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Mitsuhiro Kiyono; Teiyuu Kimura; Noriyuki Ozaki; Kenichi Yanai; Shinji Kashiwada; Fumiaki Mizuno; Kazuhisa Onda - Web page: https://patentgrep.com/patent/US20210239802A1 ## CPC - G01S 7/4813: {Housing arrangements} - G01S 7/4817: {relating to scanning} - G01S 7/4861: Circuits for detection, sampling, integration or read-out - G01S 17/08: for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) - G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) - G01S 17/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) - 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 ## Abstract An optical detector is configured to project a projection beam toward a measurement area and detect a return beam from the measurement area. The optical detector includes: a projecting optical system that forms a projection optical axis to project the projection beam; a receiving optical system that forms a receiving optical axis to receive the return beam, and a housing having a housing chamber to house the projecting optical system and the receiving optical system, and an optical window for the projection beam and the return beam to travel between the housing chamber and the measurement area. The projection optical axis and the receiving optical axis are offset from each other to define an overlap region inside the housing chamber where footprints of the projection beam and the return beam overlap with each other. ## Claims ### Claim 1 An optical detector configured to project a projection beam toward a measurement area and detect a return beam from the measurement area, the optical detector comprising: a projecting optical system that forms a projection optical axis to project the projection beam; a receiving optical system that forms a receiving optical axis to receive the return beam, and a housing having a housing chamber to house the projecting optical system and the receiving optical system, and an optical window for the projection beam and the return beam to travel between the housing chamber and the measurement area, wherein the projection optical axis and the receiving optical axis are offset from each other to define an overlap region inside the housing chamber where footprints of the projection beam and the return beam overlap with each other. ### Claim 2 (depends on 1) The optical detector according to claim 1, further comprising: a cover member that closes the optical window to be capable of transmitting both of the projection beam and the return beam; a single photon avalanche photodiode light receiving element housed in the housing chamber to generate an electric pulse in response to a reception of a photon by the return beam passing through the receiving optical system; and at least one processor that sets a sampling period of the single photon avalanche photodiode light receiving element such that the return beam is separated from a noise light caused by the projection beam reflected by the cover member. ### Claim 3 (depends on 1) The optical detector according to claim 1, further comprising: a scanning mirror housed in the housing chamber commonly for the projection beam and the return beam, wherein the scanning mirror has a reflecting surface to scan the projection beam from the projecting optical system toward the measurement area and to guide the return beam toward the receiving optical system. ### Claim 4 (depends on 3) The optical detector according to claim 3, wherein the footprint of the projection beam and the footprint of the return beam partially overlap with each other on the reflecting surface. ### Claim 5 (depends on 1) The optical detector according to claim 1, further comprising: a light emitting unit housed in the housing chamber, the light emitting unit having a light emitting window elongated in an extension direction to emit the projection beam by laser light from the light emitting window toward the projecting optical system; and a scanning mirror housed in the housing chamber and having a reflecting surface that scans the projection beam from the projecting optical system toward the measurement area, wherein the projecting optical system has a focal length such that an image of the light emitting window is formed outside the housing chamber, and the scanning mirror is arranged at a position where an image of the light emitting window is in a non-imaging state. ### Claim 6 (depends on 5) The optical detector according to claim 5, wherein the scanning mirror is arranged at a position where the projection beam is incident in a near-field pattern. ### Claim 7 (depends on 1) The optical detector according to claim 1, further comprising: a light emitting unit housed in the housing chamber, the light emitting unit having a light emitting window elongated in an extension direction to emit the projection beam by laser light from the light emitting window toward the projecting optical system, wherein the projecting optical system has a focal length such that an image of the light emitting window is formed outside the housing chamber, and the optical window is arranged at a position where an image of the light emitting window is in a non-imaging state. ### Claim 8 (depends on 7) The optical detector according to claim 7, wherein the optical window is arranged at a position where the projection beam is incident in a near-field pattern. ### Claim 9 (depends on 1) The optical detector according to claim 1, wherein the projection optical axis and the receiving optical axis are arranged at a distance from each other and to extend in a common direction common to each other. ### Claim 10 (depends on 9) The optical detector according to claim 9, wherein the projecting optical system and the receiving optical system are arranged adjacent to each other in a direction perpendicular to the common direction, the receiving optical system has an optical lens arranged to include the receiving optical axis, and an outer peripheral contour of the optical lens has an arc contour portion formed in an arc shape and a string contour portion formed in a string shape that faces the projecting optical system at a position excluding a range formed by the arc contour portion.