JP2020063970A - Light projecting/receiving device and distance measuring apparatus - Google Patents

Abstract

To provide a light projecting/receiving device capable of suppressing crosstalk of light among plural light receiving segments and capable of projecting and receiving light accurately, and to provide a distance measuring apparatus capable of measuring a distance accurately.SOLUTION: A light projecting/receiving device includes: a light source for emitting light; a light receiving element 16 for receiving reflection light reflected by an object after the light is projected toward the object, and having a light reception surface 16S in which plural light receiving segments 16A are disposed; a light collection optical system for condensing reflection light and guiding it to each of the plural light receiving elements; and a light-shielding wall 17 projecting from an area between the mutually adjacent light receiving segments on a light reception surface of the light receiving element and having a light shielding property for the light.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a light emitting and receiving device that projects and receives light, and a distance measuring device that performs optical distance measurement.

  2. Description of the Related Art Conventionally, there is known a distance measuring device that measures a distance to an object by irradiating the object with light and detecting light reflected by the object. The distance measuring device includes a light emitting and receiving device that emits light and receives light, and a distance measuring unit that generates distance measuring information based on a light emitting and receiving result of light by the light emitting and receiving device. For example, Patent Document 1 discloses an optical radar device including a light projecting unit, a light receiving unit, and a distance measuring unit.

JP 2007-85832

  For example, the distance measuring device is provided with a light source that emits light for distance measurement and a light receiving element that receives light reflected by an object. In addition, for example, by using a light receiving element having a plurality of light receiving segments that independently receive light, it is possible to collectively perform a plurality of regions (such as a plurality of objects and a plurality of surface areas of the objects) at once. It is possible to project and receive light.

  Here, considering that light projection / light reception and distance measurement are accurately performed on each of the plurality of regions, for example, one light reception segment of the plurality of light reception segments includes one of the plurality of regions. It is preferable that only the light returning from the one region corresponding to the one light receiving segment is received.

  Therefore, for example, it is preferable that one light receiving segment does not receive light returning from a plurality of regions, and that one light receiving segment should not receive light that should be received by another light receiving segment. In other words, it is preferable that the light crosstalk between the plurality of light receiving segments is suppressed.

  The present invention has been made in view of the above points, and it is an object of the present invention to suppress the crosstalk of light between a plurality of light receiving segments, and to perform an accurate light emitting and receiving device and an accurate distance measurement. One of the purposes is to provide a distance measuring device capable of

  The invention according to claim 1 receives a light source that emits light, and a light receiving surface on which a plurality of light receiving segments are arranged, which receives reflected light that is projected toward the object and reflected by the object. A light-receiving element having a light-receiving element, a light-collecting optical system for guiding reflected light to each of a plurality of light-receiving segments, and a light-receiving surface of the light-receiving element protruding from a region between light-receiving segments adjacent to each other and shielding the light. And a light shielding wall having a property.

  Further, the invention according to claim 7 has the light emitting and receiving device according to claim 1 and a distance measuring unit for measuring a distance to an object based on a light receiving result of reflected light by the light receiving element. Characterize.

FIG. 1 is a diagram showing an overall configuration of a distance measuring device according to a first embodiment. FIG. 3 is a diagram showing a light emitting surface of a light source in the distance measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing a configuration example of projected light in the distance measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing a light receiving element and a light shielding wall in the distance measuring device according to the first embodiment. FIG. 3 is a diagram showing a path of reflected light to a focusing optical system in the distance measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing an arrangement example of a condensing optical system, a light receiving element, and a light shielding wall in the distance measuring device according to the first embodiment. FIG. 3 is a top view of a light receiving element and a light shielding wall in the distance measuring device according to the first embodiment. FIG. 3 is a cross-sectional view of a light receiving element and a light shielding wall in the distance measuring device according to the first embodiment. FIG. 3 is a cross-sectional view of a light receiving element and a light shielding wall in the distance measuring device according to the first embodiment. FIG. 3 is a diagram showing a path of reflected light in the distance measuring device according to the first embodiment. 7 is a cross-sectional view of a light receiving element and a light shielding wall in a distance measuring device according to a modification 1 of Example 1. FIG. 7 is a top view of a light receiving element and a light shielding wall in a distance measuring device according to a second modification of the first embodiment. FIG. 7 is a cross-sectional view of a light receiving element and a light shielding wall in a distance measuring device according to a second modification of the first embodiment. FIG. 6 is a top view of a light receiving element and a light shielding wall in the distance measuring device according to the second embodiment. FIG. 6 is a cross-sectional view of a light receiving element and a light shielding wall in the distance measuring device according to the second embodiment.

  Examples of the present invention will be described in detail below.

  FIG. 1 is a schematic layout of the distance measuring device 10 according to the first embodiment. The distance measuring device 10 is a scanning type distance measuring device that performs optical scanning of a predetermined area (hereinafter, referred to as a scanning area) R0 and measures a distance to an object OB existing in the scanning area R0. The distance measuring device 10 will be described with reference to FIG. Note that the scanning region R0 and the object OB are schematically shown in FIG.

  First, the distance measuring device 10 includes a light source 11 that generates and emits light (hereinafter, referred to as primary light) L1. In the present embodiment, the light source 11 generates laser light having a peak wavelength in the infrared region as the primary light L1 and emits this laser light intermittently.

  The distance measuring device 10 has a shaping optical system (or a projection optical system) 12 that shapes the primary light L1 for projection. The shaping optical system 12 includes, for example, at least one lens that condenses the primary light L1 and determines its cross-sectional shape (beam shape) and optical path.

  The distance measuring device 10 includes a deflecting element (first deflecting element) 13 that deflects the primary light L1 in a directionally variable direction and projects the light as projection light (hereinafter, referred to as secondary light L2). The deflection element 13 performs a periodic operation to periodically change the deflection direction of the primary light L1. The deflecting element 13 emits the primary light L1 while bending the traveling direction thereof, and periodically changes the bending direction thereof. The primary light L1 deflected by the deflecting element 13 is projected as secondary light L2 toward the scanning region R0.

  In the present embodiment, the deflection element 13 has at least one rotating mirror 13A that rotates about the rotation axis AY and reflects the primary light L1. For example, the deflection element 13 includes a polygon mirror. In the present embodiment, the deflecting element 13 periodically changes the reflection direction of the primary light L2 by reflecting the primary light L2 while the rotating mirror 13A rotates. That is, in this embodiment, the secondary light L2 is the primary light L1 reflected by the turning mirror 13A of the deflection element 13.

  The scanning region R0 is a virtual three-dimensional space onto which the primary light L1 (secondary light L2) that has passed through the deflection element 13 is projected. Further, in the present embodiment, the light source 11 emits laser light having a linear cross-sectional shape extending along the axial direction of the rotation axis AY of the rotation mirror 13A as the primary light L1.

  In FIG. 1, the outer edge of the scanning region R0 is schematically shown by a broken line. Further, in FIG. 1, the main optical axes of the primary light L1 and the secondary light L2 are shown by solid lines, and the optical paths of the ends of the primary light L1 along the axial direction of the rotation axis AY are shown by broken lines.

  For example, the scanning region R0 includes a height direction direction range along a longitudinal direction (hereinafter, referred to as a first direction) D1 in a cross section of the secondary light L2 and a deflection direction of the primary light L1 by the deflection element 13. A widthwise direction range along a direction (hereinafter, referred to as a second direction) D2 corresponding to the variable range and a distance direction range (that is, a depth range) in which the secondary light L2 can maintain a predetermined intensity. Can be defined as a conical space having.

  Further, when a virtual plane distant from the deflecting element 13 in the scanning region R0 by a predetermined distance is defined as a scanning plane R1, the scanning plane R1 is two-dimensionally spread along the first and second directions D1 and D2. Can be defined as an area. The secondary light L2 is projected toward the scanning region R0 so as to scan the scanning surface R1.

  Further, as shown in FIG. 1, when an object OB (that is, an object or a substance having a reflectivity or a scattering property with respect to the secondary light L2) is present in the scanning region R0, the secondary light L2 is the object OB. Is reflected or scattered by. A part of the secondary light L2 reflected by the object OB is a tertiary light (that is, a reflected light or a return light) L3, and an optical path substantially the same as the secondary light L2 is opposite to the secondary light L2. It goes in the direction and returns to the deflection element 13.

  The distance measuring device 10 is provided on the optical path of the tertiary light L3, in the present embodiment, on the optical path common to the primary light L1 and the tertiary light L1 between the deflecting element 13 and the projection optical system 12, A deflection element (second deflection element) 14 that deflects the third-order light L3 is included. For example, the deflection element 14 is an optical separation element that separates the primary light L1 and the tertiary light L3 by transmitting the primary light L1 and reflecting the tertiary light L3, and in the present embodiment, is a beam splitter. is there.

  In this embodiment, the deflecting element 13 is a movable deflecting element for scanning that deflects the primary light L1 in a directionally variable manner by operating. On the other hand, the deflection element 14 is a fixed deflection element for separating the primary light L1 and the tertiary light L3.

  The distance measuring device 10 has a condensing optical system (or a light receiving optical system) 15 that condenses the tertiary light L3 deflected by the deflecting element 14. The condensing optical system 15 includes, for example, at least one lens.

  The distance measuring device 10 includes a light receiving element 16 that is provided on the optical path of the tertiary light L3 condensed by the condensing optical system 15 and that receives the tertiary light L3. For example, the light receiving element 16 detects the tertiary light L3 and generates an electric signal according to the tertiary light L3.

  The light receiving element 16 generates the electric signal as a detection result (light reception result) of the third-order light L3. That is, the distance measuring device 10 generates the electric signal generated by the light receiving element 16 as the scanning result of the scanning region R0.

  The distance measuring device 10 has a light shielding wall 17 provided so as to limit the light incident on the light receiving element 16. The light shielding wall 17 is configured to suppress the incidence of light other than the light generated by the tertiary light L3, that is, the secondary light L2 being projected on the scanning region R0 (object OB), into the light receiving element 16. ing. Details of the light receiving element 16 and the light shielding wall 17 will be described later.

  The distance measuring device 10 has a control unit 20 that drives and controls the light source 11, the deflection element 13, and the light receiving element 16. For example, in the present embodiment, the control unit 20 includes a light source control unit 21 that drives and controls the light source 11, and a deflection element control unit 22 that drives and controls the deflection element 13.

  The control unit 20 also includes a distance measuring unit 23 that drives the light receiving element 16 and measures the distance to the object OB based on the light reception result of the third-order light L3 by the light receiving element 16. In the present embodiment, the distance measuring unit 23 detects a pulse indicating the tertiary light L3 from the electric signal generated by the light receiving element 16. Further, the distance measuring unit 23 uses the time-of-flight method based on the time difference between the projection timing of the secondary light L2 and the reception timing of the tertiary light L3 to reach the object OB (or a partial surface area thereof). To measure the distance. Further, the distance measuring unit 23 generates data indicating the measured distance information (distance measuring data).

  Further, in the present embodiment, the distance measuring unit 23 distinguishes the scanning region R0 (scanning surface R1) into a plurality of distance measuring points (scanning points), and the distance measuring results (distances) of each of the plurality of distance measuring points. An image (distance-measuring image) of the scanning region R0 in which (value) is shown as a pixel is generated. In the present embodiment, the distance measuring unit 23 associates the distance measuring point with information indicating the displacement of the rotating mirror 13A and generates image data indicating a two-dimensional map or a three-dimensional map of the scanning region R0.

  Further, the distance measuring unit 23 sets, for example, a change cycle in the direction of projection of the secondary light L2, that is, a scanning cycle that is a cycle of scanning the scanning region R0, as a generation cycle of a distance measurement image, and one for each scanning cycle. Generate a ranging image.

  The scanning cycle means, for example, a period until the predetermined displacement of the rotating mirror 12A returns to the displacement again when the distance measuring device 10 periodically performs optical scanning on the scanning region R0. Further, the distance measuring unit 23 may have a display unit (not shown) that displays a plurality of generated distance measuring images as moving images in time series.

  FIG. 2 is a diagram schematically showing the light emitting surface 11S of the light source 11. Further, FIG. 3 is a diagram schematically showing the locus of the secondary light L2 on the scanning plane R1. In the present embodiment, as shown in FIG. 2, the light source 11 emits laser light having a linear or elliptical beam shape having the first direction D1 as the longitudinal direction as the primary light L1. Have. In the present embodiment, the laser element 11A emits a linear laser beam having a cross-sectional shape in which the first direction D1 is the longitudinal direction and the second direction D2 is the lateral direction.

  Further, the deflection element 13 variably deflects the primary light L2 along the second direction D2. Therefore, as shown in FIG. 3, in the present embodiment, the distance measuring device 10 changes the projection direction (emission direction) of the linear secondary light L2 extending in the first direction D1 to the second direction D2. The scanning plane R1 is scanned by changing the scanning direction.

  FIG. 4 is a perspective view of the light receiving element 16 and the light shielding wall 17. First, in the present embodiment, the light receiving element 16 has a light receiving surface 16S in which a plurality of light receiving segments 16A are arranged along the direction DA. In the present embodiment, the light receiving element 16 has a plurality of light receiving segments 16A arranged in a line on the light receiving surface 16S. In the present embodiment, the light receiving element 16 is a line sensor having a linear light receiving surface 16S.

  In the present embodiment, each of the light receiving segments 16A performs the light receiving operation of the third-order light L3 independently of each other. Further, each of the light receiving segments 16A has a detection element that performs light detection by at least one photoelectric conversion element.

  Next, in the present embodiment, the light shielding wall 17 is formed on the light receiving surface 16S so as to project from the light receiving surface 16S of the light receiving element 16. For example, the surface of the light shielding wall 17 has a reflectivity or a scatter property with respect to the tertiary light L3. In the present embodiment, the surface of the light shielding wall 17 has reflectivity and scattering property for the third-order light L3.

  Further, in this embodiment, the light shielding wall 17 is formed so as to surround the outer edge region of the light receiving segment 16A in the light receiving surface 16S of the light receiving element 16. Further, in the present embodiment, the light shielding wall 17 is formed in a lattice shape so that a plurality of unit lattices are arranged on the light receiving surface 16S of the light receiving element 16.

  Hereinafter, the direction in which the light receiving segments 16A are arranged in the light receiving surface 16S of the light receiving element 16 may be referred to as the arrangement direction of the light receiving segments 16A (or the length direction of the light receiving surface 16S) DA. Further, a direction perpendicular to the arrangement direction DA of the light receiving segments 16A in the light receiving surface 16S may be referred to as a side direction DB of the light receiving segment 16A (or a width direction of the light receiving surface 16S) DB. In this embodiment, the arrangement direction DA of the light receiving segments 16A corresponds to the first direction D1 and the side direction DB corresponds to the second direction D2.

  FIG. 5A schematically illustrates the spot shape of the secondary light L2 irradiated on the object OB and the path of the tertiary light L3, which is the secondary light L2 reflected by the object OB, to the condensing optical system 15. FIG. As shown in FIG. 5A, the region of the target object OB irradiated with the secondary light L2 has a linear shape whose longitudinal direction is the first direction D1. Then, light having various incident angles enters the condensing optical system 15 as the tertiary light L3 from the irradiation area of the secondary light L2 in the object OB.

  FIG. 5B is a diagram schematically showing an arrangement relationship between the condensing optical system 15, the light receiving element 16 and the light shielding wall 17. First, the light receiving surface 16S of the light receiving element 16 is formed in a planar shape and is arranged so as to extend perpendicularly to the optical axis of the condensing optical system 15.

  Further, the third-order light L3 that has entered the condensing optical system 15 is divided into a plurality of partial lights (hereinafter, referred to as partial third-order light) L3A according to the incident angle of the condensing optical system 15. You can Each of these partial tertiary lights L3A becomes the light received by each of the light receiving segments 16A, as shown in FIG. 5B.

  For example, among a plurality of partial lights L3A, a partial light (that is, a component with an incident angle of 0 degree in the third-order light L3) proceeding in a direction parallel to the optical axis of the condensing optical system 15 is a plurality of light receiving segments. The light is incident on the light receiving segment 16AA arranged in the central portion of 16A, and is received and detected by the light receiving segment 16AA.

  In this way, an electric signal corresponding to the partial tertiary light L3A received for each light receiving segment 16A is generated by each light receiving segment 16A. Therefore, when the area where the secondary light L2 is projected once in the scanning area R0 is divided into a plurality of partial areas corresponding to each of the light receiving segments 16A along the first direction D1, Scanning information for a plurality of partial areas is collectively acquired. Further, by repeating this along the second direction D2, the scan information of the entire scan region R0 is acquired.

  Further, in the present embodiment, the light shielding wall 17 projects from the light receiving surface 16S toward the condensing optical system 15 along the direction perpendicular to the light receiving surface 16S. Therefore, the wall surface (side surface) 17S of the light shielding wall 17 extends in the direction perpendicular to the light receiving surface 16S.

  Further, in this embodiment, the condensing optical system 15 is arranged so that the third-order light L3 (reflected light) is condensed at a position (focal position) P1 which is separated from the light receiving surface 16S of the light receiving element 16. There is. Specifically, for example, in the case where the condensing optical system 15 has at least one lens, when the position of the lens is set to the position P0, it is farther from the lens than the position P1 which is separated by the focal length LF of the lens. The light-receiving surface 16S of the light-receiving element 16 is arranged at the open position.

  In the present embodiment, the condensing optical system 15 is arranged so that the third-order light L3 is condensed in the space on the light receiving surface 16S defined by the light shielding wall 17. Therefore, as shown in FIG. 5, the third-order light L3 (each of the partial third-order lights L3A) is incident on each of the light-receiving segments 16A of the light-receiving element 16 in a state where it is not completely condensed.

  FIG. 6 is a top view of the light receiving element 16 and the light shielding wall 17. As shown in FIG. 6, in the light receiving element 16A, the light receiving segments 16A are arranged apart from each other. Therefore, on the light receiving surface 16S of the light receiving element 16, an area (hereinafter, referred to as a segment area) A0 in which the light receiving segment 16A is formed and an area (hereinafter, referred to as an intersegment area) A1 between the adjacent light receiving segments 16A are provided. , Are formed.

  In addition, the light shielding wall 17 has a first wall portion 17A formed in the inter-segment area A1 and a second wall portion 17B formed so as to surround the entire segment area A0. In the present embodiment, the second wall portion 17B is formed in the side surface region of the light receiving segment 16A which is not adjacent to the other light receiving segment 16A. Further, in this embodiment, the first and second wall portions 17A and 18B are integrally formed.

  7 and 8 are cross-sectional views of the light receiving element 16 and the light shielding wall 17. 7 and 8 are cross-sectional views taken along lines 7-7 and 8-8 of FIG. 6, respectively. FIG. 7 is a cross-sectional view of the light receiving element 16 and the light shielding wall 17 along the arrangement direction DA of the light receiving segments 16A. Further, FIG. 8 is a cross-sectional view of the light receiving element 16 and the light shielding wall 17 along the side direction DB of the light receiving segment 16A.

  First, as shown in FIGS. 7 and 8, the light receiving element 16 includes a substrate 31, a plurality of photodetector elements 32 juxtaposed on the substrate 31, and a substrate so as to cover the entire upper surfaces of the plurality of photodetector elements 32. And a light-transmitting plate 33 formed integrally on 31.

  Each of the light detection elements 32 has at least one photoelectric conversion element that performs photoelectric conversion on the tertiary light L3. In this embodiment, each of the photodetector elements 32 includes at least one avalanche photodiode operating in Geiger mode. In addition, in the present embodiment, the translucent plate 33 has a flat plate shape and has translucency with respect to the tertiary light L3.

  In this embodiment, as shown in FIG. 7, one photodetector element 32 and a portion of the translucent plate 33 above the one photodetector element 32 constitute one light receiving segment 16A of the light receiving element 16. To do. Further, the upper surface (surface on the side of the light shielding wall 17) of the light transmitting plate 33 constitutes the light receiving surface 16S of the light receiving element 16.

  The first and second wall portions 17A and 17B of the light shielding wall 17 are formed on the light transmitting plate 33. In this embodiment, the first and second wall portions 17A are joined to the translucent plate 33. The wall surface 17S of the light shielding wall 17 (see FIG. 5) is provided on the first wall portion 17A on the segment area A0 side and on the second wall portion 17B on the segment area A0 side. The second wall surface 18BS is provided.

  Note that, for example, in the example shown in FIGS. 6 to 8, the first wall portion 17A of the light shielding wall 17 has the same or the same spacing as the inter-segment area A1 (distance between adjacent photodetection elements 32 in the arrangement direction DA). It has a smaller thickness than this. However, the thickness of the light shielding wall 17 is not limited to this. For example, the light shielding wall 17 may have a thickness larger than the distance between the inter-segment regions A1. The light shielding wall 17 will be slightly formed on the segment area A0.

  FIG. 9 is a diagram schematically showing the path of the tertiary light L3 that has entered the light shielding wall 17. FIG. 9 is a sectional view similar to FIG. 7. First, the first wall portion 17A of the light shielding wall 17 is provided in the region between the adjacent light receiving segments 16A on the light receiving surface 16S.

  The third-order light L3 (partial third-order light L3A) that has entered into one space defined by the light-shielding wall 17 is light that should be received by one light-receiving segment 16A corresponding to the one space. The light shielding wall 17 suppresses the tertiary light L3 that has entered the space from proceeding to another space. Therefore, the partial tertiary light L3A that should be received by one light receiving segment 16A is received by another light receiving segment 16A, that is, crosstalk of light between the light receiving segments 16A is suppressed.

  Further, in the present embodiment, as shown in FIG. 9, the first wall surface 17AS of the first wall portion 17A in the light shielding wall 17 is configured to scatter the tertiary light L3. In this embodiment, all the wall surfaces 17S of the light shielding wall 17 are configured to scatter light. For example, the light shielding wall 17 has its wall surface 17S subjected to light scattering processing such as unevenness.

  Therefore, the tertiary light L3 (partial tertiary light L3A) incident on the wall surface 17S of the light shielding wall 17 is scattered by the light shielding wall 17, as shown in FIG. Further, the tertiary light L3 is scattered each time it enters the light shielding wall 17.

  This makes it easier for the third-order light L3 to enter the entire segment area A0. Therefore, the light receiving segment 16A (photodetection element 32) as a whole can receive the tertiary light L3. Thereby, the tertiary light L3 can be reliably received and detected.

  Further, in the present embodiment, each of the light receiving segments 16A has a light detecting element 32 including at least one avalanche photodiode operating in the Geiger mode. Therefore, the larger the area where the partial tertiary light L3 is incident on the photodetector 32, the more accurately the photodetection operation (photon counting) can be performed. On the other hand, since the light shielding wall 17 has a light scattering property, the partial tertiary light L3 can be received by the entire light receiving segment 16A. Therefore, the third-order light L3 can be received and detected more accurately.

  In this embodiment, the case where the light receiving element 16 has the light transmitting plate 33 integrally formed and the light shielding wall 17 is formed on the light transmitting plate 33 has been described. However, the configurations of the light receiving element 16 and the light shielding wall 17 are not limited to this.

  FIG. 10 is a cross-sectional view of the light receiving element 16M and the light shielding wall 18 in the distance measuring device 10A according to the first modification of the present embodiment. FIG. 10 is a sectional view of the light receiving element 16M and the light shielding wall 18 similar to FIG. The distance measuring device 10A has the same configuration as the distance measuring device 10 except for the configurations of the light receiving element 16M and the light shielding wall 18.

  In the distance measuring device 10A, the light receiving element 16M includes a substrate 31 and a plurality of light detecting elements 32, and a plurality of light transmitting plates 34 each formed on the upper surface of the light detecting element 32. In this modification, one photodetector element 32 and the translucent plate 34 on the photodetector element 32 form one light receiving segment 16A in the light receiving element 16M. Further, each of the upper surfaces of the light transmitting plate 34 constitutes the light receiving surface 16S of the light receiving element 16M.

  Further, in this modification, the light shielding wall 18 is formed on the substrate 31 of the light receiving element 16M. Specifically, the first wall portion 18A of the light shielding wall 18 is formed in the region A1 between the adjacent photodetector elements 32 (that is, the inter-segment region) A1 on the substrate 31 of the light receiving element 16M. The second wall portion 18B is formed so as to surround the entire photodetector element 32 in the outermost region of the photodetector element 32 on the substrate 31.

  In this modification, the first and second wall portions 18A and 18B of the light shielding wall 18 are formed from the upper surface of the substrate 31 beyond the light receiving surface 16S, and thus protrude from the light receiving surface 16S. There is.

  In this modification, the light blocking wall 18 is provided between the side surfaces of the photodetector element 32. Therefore, for example, after the partial tertiary light L3A is incident on the light transmitting plate 34 toward the one light receiving segment 16A, the partial third light L3A is received by another light receiving segment 16A other than the one light receiving segment 16A. Is suppressed. Therefore, the effect of suppressing crosstalk between the light receiving segments 16A is large. The light shielding wall 18 may be provided in this manner.

  FIG. 11 is a top view of the light receiving element 16 and the light shielding wall 19 in the distance measuring device 10B according to the second modification of the present embodiment. FIG. 12 is a sectional view of the light receiving element 16 and the light shielding wall 19. 12 is a sectional view taken along line 12-12 in FIG. 11, and is a sectional view of the light receiving segment 16A in the lateral direction DB. The distance measuring device 10B has the same configuration as the distance measuring device 10 except for the configuration of the light shielding wall 19.

  In the distance measuring device 10B, the light blocking wall 19 is a light blocking wall except that the second wall surface 19AS provided on the light receiving segment 16A side of the second wall portion 19 is inclined with respect to the light receiving surface 16S. It has the same structure as the wall 17.

  In this modification, each of the second wall portions 19A has a second wall surface 19AS provided on the light receiving segment 16A side and forming an angle with the light receiving surface 16S of greater than 90 °. In the present modification, the second wall portion 19A of the light shielding wall 19 is arranged with respect to the light receiving surface 16S such that the distance between the second wall portion 19A and the other facing second wall portion 19 gradually increases as the distance from the light receiving surface 16S increases. The second wall surface 19AS is inclined.

  By configuring the second wall portion 19A in this manner, most of the partial tertiary light L3A that enters the light receiving segment 16A easily enters the light blocking wall 19 before entering the light receiving segment 16A. Therefore, the partial tertiary light L3A can be guided to the entire light receiving segment 16A while being reflected and scattered. Therefore, the light receiving segment 16A can accurately receive the tertiary light L3 while suppressing the crosstalk of light between the light receiving segments 16A.

  In addition, in the present embodiment and its modification, the case where the light shielding walls 17 to 19 are formed so as to surround the region of the light receiving segment 16A has been described. However, the configuration of the light shielding walls 17 to 19 is not limited to this.

  For example, the light shielding wall 17 can suppress the crosstalk of light between the light receiving segments 16A by including the first wall portion 17A provided in the inter-segment area A1. Therefore, for example, the light shielding wall 17 may not have the second wall portion 17B. That is, the light blocking wall 17 may be projected from the area A1 between the adjacent light receiving segments 16A on the light receiving surface 16S of the light receiving element 16.

  In addition, in the present embodiment, for example, the case where the light shielding wall 17 is configured to have a reflectivity and a scattering property with respect to the tertiary light L3, that is, the primary light L1 reflected by the object OB will be described. did. However, the configuration of the light shielding wall 17 is not limited to this. For example, the light blocking wall 17 may have absorptivity for the primary light L1. For example, the light blocking wall 17 may have a light blocking property with respect to the primary light L1.

  Further, in the present embodiment and its modification, the case where the light receiving segments 16A of the light receiving elements 16 and 16M are arranged in one line along the first direction D1 has been described. However, the configurations of the light receiving elements 16 and 16M are not limited to this.

  For example, the light receiving element 16 may have the light receiving surface 16S on which the plurality of light receiving segments 16A are arranged. Further, the condensing optical system 15 may be configured to guide the respective third light L3 to each of the light receiving segments 16A while condensing the third light L3.

  In other words, for example, the distance measuring device 10 receives the tertiary light L3 and the light receiving element 16 having the light receiving surface 16S in which the plurality of light receiving segments 16A are arranged, and the light receiving segment while condensing the tertiary light L3. 16A, a light-collecting optical system 15, a light-shielding wall 17 protruding from an area A1 between light-receiving segments 16A adjacent to each other in the light-receiving surface 16S of the light-receiving element 16, and having a light-shielding property with respect to the primary light L1. Should have.

  Accordingly, it is possible to collectively project and receive the secondary light L2 with respect to a plurality of regions within the scanning region R0 while suppressing crosstalk of light between the light receiving segments 16A. Thus, it is possible to provide the distance measuring device 10 capable of performing an accurate distance measuring operation.

  Considering that the light receiving operation is accurately performed, for example, the wall surface 17S of the light shielding wall 17 is preferably configured to reflect or scatter the primary light L1. Further, in consideration of suppressing the reception of stray light or the like in the device other than the third-order light L3, the light shielding wall 17 has the second wall portion 17B, that is, the light shielding wall 17 of the light receiving segment 16A in the light receiving surface 16S. It is preferably formed so as to surround each outer edge region.

  Further, by disposing the condensing optical system 15 so as to condense the tertiary light L3 at the position P1 separated from the light receiving surface 16S, the tertiary light L3 can be incident on the entire light receiving segment 16A. In these cases, for example, a large effect is obtained when using the light receiving element 16 such as an avalanche photodiode operating in the Geiger mode, which has different light detection accuracy depending on the area of light incident on the detection surface.

  Further, in the present embodiment, the case where the light source 11 emits the laser light having the linear cross-sectional shape as the primary light L1 has been described. However, the configuration of the light source 11 is not limited to this. For example, the light source 11 may emit light having an arbitrary cross-sectional shape as the primary light L1. That is, the light source 11 may be configured to emit the primary light L1.

  As described above, in the present embodiment, the distance measuring device 10 includes the light source 11 that emits the primary light L1 and the deflection element 13 that deflects the primary light L1 in a variable direction and projects the secondary light L2. The secondary light L2 receives the tertiary light L3 reflected by the object OB, the light receiving element 16 having the light receiving surface 16S in which the plurality of light receiving segments 16A are arranged, and the third light L3 are received while being condensed. A condensing optical system 15 that guides each of the segments 16A, and a light shielding wall 17 that protrudes from a region A1 between the light receiving segments 16A adjacent to each other in the light receiving surface 16S of the light receiving element 16 and has a light shielding property for the primary light L1. A distance measuring unit 23 that measures the distance to the object OB based on the light reception result of the tertiary light L3 by the light receiving element 16.

  Therefore, crosstalk of light between the plurality of light receiving segments 16A is suppressed, and it is possible to provide the distance measuring device 10 capable of performing accurate distance measurement by performing accurate light projection and reception on the scanning region R0. it can.

  In this embodiment, the case where the distance measuring device 10 has the deflection element 13 has been described. However, the distance measuring device 10 may not have the deflection element 13. That is, the distance measuring device 10 may be configured to emit the primary light L1 toward a predetermined direction and receive the primary light L1 reflected by the object OB. Even in this case, crosstalk of light between the light receiving segments 16A of the light receiving element 16 can be suppressed, and accurate distance measurement can be performed. That is, the distance measuring device 10 may be configured to project and receive the primary light L1 by the light source 11 and the light receiving element 16.

  Further, the reception result of the third-order light L3 by the light receiving element 16 can be effectively used for applications other than distance measurement, for example, applications for detecting the object OB. Therefore, the distance measuring device 10 may not include the distance measuring unit 24. In this case, for example, the light source 11, the light receiving element 16, the condensing optical system 15, and the light shielding wall 17 in the distance measuring device 10 function as a light emitting and receiving device.

  As described above, in the present embodiment, the distance measuring device 10 receives the light source 11 that emits the primary light L1, the tertiary light L3 in which the primary light L1 is reflected by the object OB, and receives a plurality of light. A light receiving element 16 having a light receiving surface 16S in which the segments 16A are arranged, a condensing optical system 15 for guiding the third-order light L3 to each of the light receiving segments 16A, and a light receiving surface 16S of the light receiving element 16 adjacent to each other. And a light blocking wall 17 that projects from the area A1 between the light receiving segments 16A and has a light blocking property with respect to the primary light L1. Therefore, it is possible to provide a light projecting / receiving device capable of suppressing light crosstalk between the plurality of light receiving segments 16A in the light receiving element 16 and performing accurate light projecting / receiving.

  FIG. 13 is a top view of the light receiving element 16, the light blocking wall 17, and the scattering plate 41 in the distance measuring device 40 according to the second embodiment. Further, FIG. 14 is a cross-sectional view of the light receiving element 16, the light shielding wall 17, and the scattering plate 41. FIG. 14 is a sectional view taken along the line 14-14 in FIG.

  The distance measuring device 40 is provided in each of the spaces on the light receiving surface 16S defined by the light shielding wall 17, and has a scattering plate 41 including a plurality of scattering segments 41A that scatters the tertiary light L3. The distance measuring device 10 has the same configuration.

  In this embodiment, each of the scattering segments 41A of the scattering plate 41 has a flat plate shape and is fixed to the wall surface 17S of the light shielding wall 17. Further, in the present embodiment, each of the scattering segments 41A is arranged in the entire optical path of the tertiary light L3 to the light receiving segment 16A in the light shielding wall 17.

  Therefore, as shown in FIG. 14, the tertiary light L3 is scattered by the scattering plate 41 and then received by the light receiving segment 16A of the light receiving element 16. Therefore, the light shielding wall 17 and the scattering plate 41 can suppress the crosstalk of light between the light receiving segments 16A and allow the entire light receiving segment 16A to receive the tertiary light L3. Therefore, the light receiving accuracy of the tertiary light L3 for each of the light receiving segments 16A and for the entire light receiving element 16 is improved.

  In this embodiment, the case where the scattering plate 41 is formed on the wall surface 17S of the light shielding wall 17, that is, the side wall surface of the light shielding wall 17 has been described. However, the scattering plate 41 may be formed on the end surface of the light shielding wall 17. It suffices that the scattering plate 41 be provided on the optical path of the tertiary light L3 between the condensing optical system 15 defined by the light shielding wall 17 and each of the light receiving segments 16A. For example, the scattering plate 41 may be provided in the space on the light receiving surface 16S defined by the light shielding wall 17.

  In this way, the distance measuring device 40 is provided on the optical path of the tertiary light L3 between the condensing optical system 15 defined by the light shielding wall 17 and each of the light receiving segments 16A, and scatters the tertiary light L3. It has a scattering plate 41. Therefore, the crosstalk of light between the plurality of light receiving segments 16A in the light receiving element 16 is suppressed, and the light emitting and receiving device capable of performing accurate light emitting and receiving and the distance measuring device 40 capable of performing accurate distance measuring. Can be provided.

10, 10A, 10B, 40 Distance measuring device 16, 16M Light receiving element 17, 18, 19 Light shielding wall 41 Scattering plate

Claims (7)

A light source that emits light,
A light-receiving element having a light-receiving surface in which a plurality of light-receiving segments are arrayed, the light being projected toward an object and receiving reflected light reflected by the object.
A condensing optical system that guides each of the plurality of light receiving segments while condensing the reflected light,
A light projecting / receiving device comprising: a light blocking wall projecting from a region between the light receiving segments adjacent to each other on the light receiving surface of the light receiving element and having a light blocking property with respect to the light.   The light emitting and receiving device according to claim 1, wherein a wall surface of the light shielding wall is configured to reflect or scatter the reflected light.   The light projecting / receiving device according to claim 1, further comprising a scattering plate which is provided in a space on the light receiving surface defined by the light shielding wall and which scatters the light.   4. The light projecting / receiving device according to claim 1, wherein the light shielding wall is formed so as to surround a region of an outer edge of each of the plurality of light receiving segments on the light receiving surface.   The light projecting / receiving device according to any one of claims 1 to 4, wherein the condensing optical system is arranged so that the reflected light is condensed at a position apart from the light receiving surface. . The light shielding wall is formed so as to surround the first wall portion formed in the area between the adjacent light receiving segments on the light receiving surface and the entire area of the light receiving surface in which the plurality of light receiving segments are formed. And a second wall portion formed by:
The said 2nd wall part is provided in the said light-receiving segment side, and has the wall surface whose angle with the said light-receiving surface is larger than 90 degrees, The any one of Claim 1 thru | or 5 characterized by the above-mentioned. Emitter and receiver. A light emitting and receiving device according to any one of claims 1 to 6,
A distance measuring unit that measures a distance to the object based on a light reception result of the reflected light by the light receiving element.

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