US 12,487,331 B2
Optical detector
Mitsuhiro Kiyono, Kariya (JP); Teiyuu Kimura, Kariya (JP); Noriyuki Ozaki, Kariya (JP); Kenichi Yanai, Kariya (JP); Shinji Kashiwada, Kariya (JP); Fumiaki Mizuno, Kariya (JP); and Kazuhisa Onda, Kariya (JP)
Assigned to DENSO CORPORATION, Kariya (JP)
Filed by DENSO CORPORATION, Kariya (JP)
Filed on Jan. 28, 2021, as Appl. No. 17/161,441.
Claims priority of application No. 2020-015008 (JP), filed on Jan. 31, 2020.
Prior Publication US 2021/0239802 A1, Aug. 5, 2021
Int. Cl. G01S 7/481 (2006.01); G01S 7/4861 (2020.01); G01S 17/08 (2006.01)
CPC G01S 7/4813 (2013.01) [G01S 7/4817 (2013.01); G01S 7/4861 (2013.01); G01S 17/08 (2013.01)] 16 Claims
OG exemplary drawing
 
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;
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;
a light emitting unit housed in the housing chamber to emit the projection beam by laser light toward the projecting optical system; and
a scanning mirror housed in the housing chamber,
wherein
the light emitting unit has a light emitting window from which the projection beam is emitted toward the projecting optical system,
the projecting optical system and the receiving optical system are arranged in a longitudinal direction of the light emitting window,
the projection optical axis and the receiving optical axis are offset from each other to define an overlap region inside the housing chamber where a footprint of the projection beam and a footprint of the return beam overlap with each other,
the scanning mirror is configured to move within an angular range around a rotation axis that is parallel to the longitudinal direction of the light emitting window,
the projecting optical system is located between the light emitting window and the scanning mirror, the scanning mirror is positioned a distance from the light emitting window at which an aspect ratio of the footprint of the projection beam on a reflecting surface of the scanning mirror is compressed in the longitudinal direction of the light emitting window relative to an aspect ratio of the light emitting window and a line-shaped spot of the projection beam at infinity,
the projection optical axis and the receiving optical axis are arranged at a distance from each other and to extend in a common direction that is common to each other,
the projecting optical system and the receiving optical system are arranged adjacent to each other in a direction perpendicular to the common direction,
the projecting optical system has a projecting optical lens arranged to include the projection optical axis, the projecting optical lens configured to collimate the projection beam emitted from the light emitting window,
the receiving optical system has a receiving optical lens arranged to include the receiving optical axis,
an outer peripheral contour of the projecting optical lens is circular in shape, and
an outer peripheral contour of the receiving optical lens has an arc contour portion formed in an arc shape and a string contour portion formed in a string shape that faces a circular portion of the projecting optical lens at a position excluding a range formed by the arc contour portion.