Light projection / reception device and ranging device

Abstract

To provide a light projection / reception device capable of accurately projecting and receiving light by reducing optical crosstalk between multiple photosensitive segments, and to provide a ranging device capable of making accurate distance measurement.SOLUTION: A light projection / reception device is provided, comprising a light source for emitting light, a photosensitive element with a light reception surface provided with a plurality of photosensitive segments arranged thereon and configured to receive reflections of light projected toward an object and reflected by the object, a collection optical system for collecting and directing the reflected light to each of the plurality of photosensitive segments, and a light shield wall with a light shielding property protruding from regions between adjacent photosensitive segments on the light reception surface of the photosensitive element.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a light projecting and receiving device that projects and receives light, and a distance measuring device that performs optical distance measurement. [Background technology]

[0002] Distance measuring devices that measure the distance to an object by irradiating the object with light and detecting the light reflected by the object have been known. The distance measuring devices include a light projecting and receiving device that projects and receives light, and a distance measuring unit that generates distance measurement information based on the results of light projection and reception by the light projecting and receiving device. For example, Patent Document 1 discloses an optical radar device that includes a light projecting unit, a light receiving unit, and a distance measuring means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-85832 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, a 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. Also, for example, by using a light receiving element having multiple light receiving segments that receive light independently, light can be projected and received simultaneously onto each of multiple areas (multiple objects or multiple surface areas of the objects, etc.).

[0005] Here, considering the need to accurately project and receive light and measure distances to each of the multiple regions, it is preferable, for example, that one of the multiple light receiving segments receives only light returned from one region of the multiple regions that corresponds to that one light receiving segment.

[0006] Therefore, for example, it is preferable that one light receiving segment does not receive light returning from multiple regions, and that light that should be received by one light receiving segment is not received by other light receiving segments. In other words, it is preferable that optical crosstalk between multiple light receiving segments is suppressed.

[0007] The present invention has been made in consideration of the above-mentioned points, and one of its objects is to provide a light projecting and receiving device that suppresses optical crosstalk between multiple light receiving segments and is capable of accurate light projection and reception, and a distance measuring device that is capable of accurate distance measurement. [Means for solving the problem]

[0008] The light projecting and receiving device described in claim 1 is characterized by having a light source that emits light, a light receiving element that receives light reflected by the object and has a light receiving surface on which a plurality of light receiving segments are arranged, a focusing optical system that focuses the reflected light and directs it to each of the plurality of light receiving segments, and a light blocking wall that protrudes from the area between adjacent light receiving segments on the light receiving surface of the light receiving element and has a light blocking property. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing an overall configuration of a distance measuring device according to a first embodiment. [Diagram 2] 2 is a diagram showing a light exit surface of a light source in the distance measuring device according to the first embodiment. FIG. [Diagram 3] 3 is a diagram illustrating an example of the configuration of a projected light in the distance measuring device according to the first embodiment. FIG. [Figure 4] 3 is a diagram showing a light receiving element and a light blocking wall in the distance measuring device according to the first embodiment. FIG. [Figure 5A] 4 is a diagram showing a path of reflected light to a light collecting optical system in the distance measuring device according to the first embodiment. FIG. [Figure 5B] 3 is a diagram showing an example of the arrangement of a light collecting optical system, a light receiving element, and a light blocking wall in the distance measuring device according to the first embodiment. FIG. [Figure 6]2 is a top view of a light receiving element and a light blocking wall in the distance measuring device according to the first embodiment. FIG. [Figure 7] 3 is a cross-sectional view of a light receiving element and a light blocking wall in the distance measuring device according to the first embodiment. [Figure 8] 3 is a cross-sectional view of a light receiving element and a light blocking wall in the distance measuring device according to the first embodiment. [Figure 9] 4 is a diagram showing paths of reflected light in the distance measuring device according to the first embodiment. FIG. [Figure 10] 11 is a cross-sectional view of a light receiving element and a light blocking wall in a distance measuring device according to a first modified example of the first embodiment. FIG. [Figure 11] 11 is a top view of a light receiving element and a light blocking wall in a distance measuring device according to a second modified example of the first embodiment. FIG. [Figure 12] 11 is a cross-sectional view of a light receiving element and a light blocking wall in a distance measuring device according to a second modified example of the first embodiment. FIG. [Figure 13] 11 is a top view of a light receiving element and a light blocking wall in a distance measuring device according to a second embodiment. FIG. [Figure 14] 11 is a cross-sectional view of a light receiving element and a light blocking wall in a distance measuring device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described in detail below with reference to the embodiments. EXAMPLES

[0011] Fig. 1 is a schematic layout diagram of a 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 the distance to an object OB present within the scanning area R0. The distance measuring device 10 will be described with reference to Fig. 1. Note that Fig. 1 shows a schematic diagram of the scanning area R0 and the object OB.

[0012] First, the distance measuring device 10 has a light source 11 that generates and emits light (hereinafter referred to as primary light) L1. In this embodiment, the light source 11 generates laser light having a peak wavelength in the infrared region as the primary light L1 and emits it intermittently.

[0013] 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.

[0014] The distance measuring device 10 has a deflection element (first deflection element) 13 that deflects the primary light L1 in a variably directional manner and projects it as projected light (hereinafter referred to as secondary light L2). The deflection element 13 operates periodically to periodically change the deflection direction of the primary light L1. The deflection element 13 outputs the primary light L1 while bending the traveling direction of the primary light L1, and also periodically changes the bending direction. The primary light L1 deflected by the deflection element 13 is projected as secondary light L2 toward the scanning region R0.

[0015] In this embodiment, the deflection element 13 has at least one rotating mirror 13A that rotates around a rotation axis AY and reflects the primary light L1. For example, the deflection element 13 includes a polygon mirror. In this embodiment, the deflection element 13 periodically changes the reflection direction of the primary light L1 by reflecting the primary light L1 while the rotating mirror 13A rotates. That is, in this embodiment, the secondary light L2 is the primary light L1 reflected by the rotating mirror 13A of the deflection element 13.

[0016] The scanning region R0 is a virtual three-dimensional space into which the primary light L1 (secondary light L2) passing through the deflection element 13 is projected. In this embodiment, the light source 11 emits, as the primary light L1, a laser beam having a linear cross-sectional shape extending along the axial direction of the rotation axis AY of the rotating mirror 13A.

[0017] In Fig. 1, the outer edge of the scanning region R0 is shown by a dashed line. Also, in Fig. 1, the main optical axes of the primary light L1 and the secondary light L2 are shown by a solid line, and the optical path of the end of the primary light L1 along the axial direction of the rotation axis AY is shown by a dashed line.

[0018] For example, the scanning region R0 can be defined as a cone-shaped space having a height direction range along the longitudinal direction (hereinafter referred to as the first direction) D1 in the cross section of the secondary light L2, a width direction range along a direction (hereinafter referred to as the second direction) D2 corresponding to the variable range of the deflection direction of the primary light L1 by the deflection element 13, and a distance direction range (i.e., depth range) in which the secondary light L2 can maintain a predetermined intensity.

[0019] In addition, when a virtual plane in the scanning region R0 that is a predetermined distance away from the deflection element 13 is defined as a scanning surface R1, the scanning surface R1 can be defined as a two-dimensional region that spreads along the first and second directions D1 and D2. The secondary light L2 is projected toward the scanning region R0 so as to scan the scanning surface R1.

[0020] 1, when an object OB (i.e., an object or material having reflectivity or scattering properties for the secondary light L2) is present in the scanning region R0, the secondary light L2 is reflected or scattered by the object OB. A part of the secondary light L2 reflected by the object OB travels as tertiary light (i.e., reflected light or return light) L3 along substantially the same optical path as the secondary light L2 in the opposite direction to the secondary light L2, and returns to the deflection element 13.

[0021] The distance measuring device 10 has a deflection element (second deflection element) 14 that is provided on the optical path of the tertiary light L3, in this embodiment, on an optical path common to the primary light L1 and the tertiary light L3 between the deflection element 13 and the projection optical system 12 and deflects the tertiary light L3. For example, the deflection element 14 is a light 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 is a beam splitter in this embodiment.

[0022] In this embodiment, the deflection element 13 is a movable deflection element for scanning that operates to deflect the first-order light L1 in a variable direction, while the deflection element 14 is a fixed deflection element for separating the first-order light L1 and the third-order light L3.

[0023] The distance measuring device 10 has a light collecting optical system (or a light receiving optical system) 15 that collects the tertiary light L3 deflected by the deflection element 14. The light collecting optical system 15 includes, for example, at least one lens.

[0024] The distance measuring device 10 includes a light receiving element 16 that is provided on the optical path of the tertiary light L3 collected by the light collecting optical system 15 and receives the tertiary light L3. For example, the light receiving element 16 detects the tertiary light L3 and generates an electrical signal according to the tertiary light L3.

[0025] The light receiving element 16 generates the electrical signal as a detection result (light receiving result) of the tertiary light L3. That is, the distance measuring device 10 generates the electrical signal generated by the light receiving element 16 as a scanning result of the scanning region R0.

[0026] The distance measuring device 10 has a light shielding wall 17 provided to limit light incident on the light receiving element 16. The light shielding wall 17 is configured to suppress light other than the tertiary light L3, i.e., light generated by projecting the secondary light L2 onto the scanning region R0 (object OB), from being incident on the light receiving element 16. The light receiving element 16 and the light shielding wall 17 will be described in detail later.

[0027] 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 this embodiment, the control unit 20 has 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.

[0028] The control unit 20 also has a distance measuring unit 23 that drives the light receiving element 16 and measures the distance to the object OB based on the result of receiving the tertiary light L3 by the light receiving element 16. In this embodiment, the distance measuring unit 23 detects a pulse indicating the tertiary light L3 from an electrical signal generated by the light receiving element 16. The distance measuring unit 23 also measures the distance to the object OB (or a part of its surface area) by a 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. The distance measuring unit 23 also generates data (distance measurement data) indicating the measured distance information.

[0029] In this embodiment, the distance measuring unit 23 divides the scanning area R0 (scanning surface R1) into a plurality of distance measuring points (scanning points) and generates an image (distance measuring image) of the scanning area R0 that indicates the distance measuring results (distance values) of each of the plurality of distance measuring points as pixels. In this embodiment, the distance measuring unit 23 associates the distance measuring points with information indicating the displacement of the rotating mirror 13A and generates image data that indicates a two-dimensional map or a three-dimensional map of the scanning area R0.

[0030] The distance measuring unit 23 sets the period of change in the projection direction of the secondary light L2, that is, the period of scanning the scanning region R0, as the period of generating distance measuring images, and generates one distance measuring image for each scanning period.

[0031] The scanning period refers to a period from a predetermined displacement of the rotating mirror 12A to its return to the predetermined displacement when the distance measuring device 10 periodically performs optical scanning on the scanning region R0. The distance measuring unit 23 may also have a display unit (not shown) that displays the generated distance measuring images as a video in chronological order.

[0032] Fig. 2 is a diagram showing a light emission surface 11S of the light source 11. Fig. 3 is a diagram showing a trajectory of the secondary light L2 on the scanning surface R1. In this embodiment, as shown in Fig. 2, the light source 11 has a laser element 11A that emits a laser light having a linear or elliptical beam shape with a first direction D1 as a longitudinal direction as a primary light L1. In this embodiment, the laser element 11A emits a linear laser light having a cross-sectional shape with the first direction D1 as a longitudinal direction and the second direction D2 as a transverse direction.

[0033] Moreover, the deflection element 13 variably deflects the primary light L1 along the second direction D2. Therefore, as shown in Fig. 3, in this embodiment, the distance measuring device 10 scans the scanning surface R1 by changing the projection direction (emission direction) of the linear secondary light L2 extending in the first direction D1 along the second direction D2.

[0034] 4 is a perspective view of the light receiving element 16 and the light shielding wall 17. First, in this embodiment, the light receiving element 16 has a light receiving surface 16S on which a plurality of light receiving segments 16A are arranged along the direction DA. In this embodiment, the light receiving element 16 has a plurality of light receiving segments 16A arranged in a row on the light receiving surface 16S. In this embodiment, the light receiving element 16 is a line sensor having a line-shaped light receiving surface 16S.

[0035] In this embodiment, each of the light receiving segments 16A receives the tertiary light L3 independently of each other. Each of the light receiving segments 16A has a detection element that detects light by at least one photoelectric conversion element.

[0036] Next, in this embodiment, the light-shielding wall 17 is formed on the light-receiving surface 16S of the light-receiving element 16 so as to protrude from the light-receiving surface 16S. For example, the surface of the light-shielding wall 17 has reflectivity or scattering properties for the tertiary light L3. In this embodiment, the surface of the light-shielding wall 17 has reflectivity and scattering properties for the tertiary light L3.

[0037] In this embodiment, the light-shielding wall 17 is formed so as to surround the outer edge region of the light-receiving segment 16A on the light-receiving surface 16S of the light-receiving element 16. In this embodiment, the light-shielding wall 17 is formed in a lattice shape such that a plurality of unit lattices are arranged on the light-receiving surface 16S of the light-receiving element 16.

[0038] Hereinafter, the direction in which the light-receiving segments 16A are arranged within the light-receiving surface 16S of the light-receiving element 16 may be referred to as the arrangement direction DA of the light-receiving segments 16A (or the length direction of the light-receiving surface 16S). Also, the direction perpendicular to the arrangement direction DA of the light-receiving segments 16A within the light-receiving surface 16S may be referred to as the lateral direction DB of the light-receiving segments 16A (or the width direction of the light-receiving surface 16S). In this embodiment, the arrangement direction DA of the light-receiving segments 16A corresponds to the first direction D1, and the lateral direction DB corresponds to the second direction D2.

[0039] 5A is a diagram showing 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 focusing optical system 15. As shown in FIG. 5A, the area of ​​the object OB irradiated with the secondary light L2 has a line shape with the first direction D1 as the longitudinal direction. Then, light having various angles of incidence is incident on the focusing optical system 15 as the tertiary light L3 from the irradiated area of ​​the object OB with the secondary light L2.

[0040] 5B is a diagram illustrating a schematic arrangement relationship between the light collecting optical system 15, the light receiving element 16, and the light blocking wall 17. First, the light receiving surface 16S of the light receiving element 16 is formed in a flat shape and is disposed so as to extend perpendicular to the optical axis of the light collecting optical system 15.

[0041] Moreover, the tertiary light L3 incident on the focusing optical system 15 can be divided into a plurality of partial lights (hereinafter referred to as partial tertiary lights) L3A according to the angle of incidence on the focusing optical system 15. Each of these partial tertiary lights L3A becomes light received by each of the light receiving segments 16A, as shown in FIG. 5B.

[0042] For example, of the multiple partial lights L3A, the partial light L3AA that travels in a direction parallel to the optical axis of the focusing optical system 15 (i.e., the component in the tertiary light L3 with an incident angle of 0 degrees) is incident on the light receiving segment 16AA located in the center of the multiple light receiving segments 16A, and is received and detected by this light receiving segment 16AA.

[0043] In this way, an electrical signal corresponding to the partial tertiary light L3A received by each light receiving segment 16A is generated by each light receiving segment 16A. Therefore, when the area in the scanning area R0 onto which the secondary light L2 is projected at one time is divided along the first direction D1 into a plurality of partial areas corresponding to each of the light receiving segments 16A, scanning information for the plurality of partial areas is acquired collectively. Moreover, by repeating this along the second direction D2, scanning information for the entire scanning area R0 is acquired.

[0044] In this embodiment, the light-shielding wall 17 protrudes from the light-receiving surface 16S toward the light-collection optical system 15 in a direction perpendicular to the light-receiving surface 16S. Therefore, the wall surface (side surface) 17S of the light-shielding wall 17 extends in a direction perpendicular to the light-receiving surface 16S.

[0045] In this embodiment, the light-collecting optical system 15 is disposed so that the tertiary light L3 (reflected light) is collected at a position (focal position) P1 spaced apart from the light-receiving surface 16S of the light-receiving element 16. Specifically, for example, in a case where the light-collecting optical system 15 has at least one lens, when the position of the lens is set to position P0, the light-receiving surface 16S of the light-receiving element 16 is disposed at a position farther away from the lens than position P1, which is the focal length LF of the lens.

[0046] In this embodiment, the light-collecting optical system 15 is disposed so that the tertiary light L3 is collected within a space on the light-receiving surface 16S defined by the light-shielding wall 17. Therefore, as shown in Fig. 5, the tertiary light L3 (each of the partial tertiary light 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 collected.

[0047] Fig. 6 is a top view of the light receiving element 16 and the light shielding wall 17. As shown in Fig. 6, the light receiving segments 16A are arranged spaced apart from one another in the light receiving element 16. Therefore, on the light receiving surface 16S of the light receiving element 16, there are formed an area A0 where the light receiving segments 16A are formed (hereinafter referred to as a segment area) and an area A1 between adjacent light receiving segments 16A (hereinafter referred to as an inter-segment area).

[0048] The light-shielding wall 17 has a first wall 17A formed in the inter-segment region A1 and a second wall 17B formed to surround the entire segment region A0. In this embodiment, the second wall 17B is formed in a region on the side of the light-receiving segment 16A that is not adjacent to another light-receiving segment 16A. In this embodiment, the first and second walls 17A and 17B are integrally formed.

[0049] Fig. 7 and Fig. 8 are cross-sectional views of the light receiving element 16 and the light shielding wall 17. Fig. 7 and Fig. 8 are cross-sectional views taken along lines 7-7 and 8-8 in Fig. 6, respectively. Fig. 7 is a cross-sectional view of the light receiving element 16 and the light shielding wall 17 taken along the arrangement direction DA of the light receiving segment 16A. Fig. 8 is a cross-sectional view of the light receiving element 16 and the light shielding wall 17 taken along the lateral direction DB of the light receiving segment 16A.

[0050] First, as shown in Figures 7 and 8, the light receiving element 16 has a substrate 31, a plurality of light detecting elements 32 arranged in parallel on the substrate 31, and a light-transmitting plate 33 integrally formed on the substrate 31 so as to cover the entire upper surfaces of the plurality of light detecting elements 32.

[0051] 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 light detection elements 32 includes at least one avalanche photodiode that operates in a Geiger mode. In this embodiment, the light-transmitting plate 33 has a flat plate shape and is translucent to the tertiary light L3.

[0052] 7, one light detecting element 32 and a portion of the light-transmitting plate 33 above the one light detecting element 32 constitute one light receiving segment 16A of the light receiving element 16. In addition, the upper surface of the light-transmitting plate 33 (the surface on the light-shielding wall 17 side) constitutes a light receiving surface 16S of the light receiving element 16.

[0053] Moreover, 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 and 17B are joined to the light-transmitting plate 33. Moreover, the wall surface 17S (see FIG. 5) of the light-shielding wall 17 has a first wall surface 17AS provided on the segment area A0 side of the first wall portion 17A, and a second wall surface 18BS provided on the segment area A0 side of the second wall portion 17B.

[0054] 6 to 8, the first wall portion 17A of the light-shielding wall 17 has a thickness equal to or smaller than the interval between the inter-segment regions A1 (the distance between adjacent light-detecting elements 32 in the array direction DA). 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 interval between the inter-segment regions A1. The light-shielding wall 17 is formed slightly above the segment regions A0.

[0055] Fig. 9 is a diagram showing a schematic diagram of a path of the tertiary light L3 incident on the light-shielding wall 17. Fig. 9 is a cross-sectional view similar to Fig. 7. First, a first wall portion 17A of the light-shielding wall 17 is provided in an area between adjacent light-receiving segments 16A on the light-receiving surface 16S.

[0056] Moreover, the tertiary light L3 (partial tertiary light L3A) incident into one space defined by the light-shielding wall 17 is light to be received by one light-receiving segment 16A corresponding to that one space. The light-shielding wall 17 prevents the tertiary light L3 incident into that space from proceeding to another space. Therefore, the partial tertiary light L3A to be received by one light-receiving segment 16A is prevented from being received by another light-receiving segment 16A, i.e., optical crosstalk between the light-receiving segments 16A is prevented.

[0057] In this embodiment, as shown in Fig. 9, the first wall surface 17AS of the first wall portion 17A of the light-shielding wall 17 is configured to scatter the tertiary light L3. In this embodiment, all of the wall surfaces 17S of the light-shielding wall 17 are configured to scatter light. For example, the light-shielding wall 17 has a light-scattering treatment such as unevenness applied to its wall surface 17S.

[0058] 9, the tertiary light L3 (partial tertiary light L3A) incident on the wall surface 17S of the baffle wall 17 is scattered by the baffle wall 17. Moreover, the tertiary light L3 is scattered every time it is incident on the baffle wall 17.

[0059] This makes it easier for the tertiary light L3 to be incident on the entire segment area A0. Therefore, the tertiary light L3 can be received by the entire light receiving segment 16A (light detecting element 32). This makes it possible to reliably receive and detect the tertiary light L3.

[0060] In this embodiment, each of the light receiving segments 16A has a light detecting element 32 including at least one avalanche photodiode operating in Geiger mode. Therefore, the larger the area in the light detecting element 32 on which the partial tertiary light L3 is incident, the more accurately the light detecting operation (photon counting) can be performed. On the other hand, since the light shielding wall 17 has light scattering properties, the partial tertiary light L3 can be received by the entire light receiving segment 16A. Therefore, the tertiary light L3 can be received and detected more accurately.

[0061] In this embodiment, the light receiving element 16 is integrally formed with the light-transmitting plate 33, and the light-shielding wall 17 is formed on the light-transmitting plate 33. However, the configurations of the light receiving element 16 and the light-shielding wall 17 are not limited to this.

[0062] 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 modified example of this embodiment. Fig. 10 is a cross-sectional view of the light receiving element 16M and the light shielding wall 18 similar to Fig. 7. The distance measuring device 10A has a similar configuration to the distance measuring device 10, except for the configurations of the light receiving element 16M and the light shielding wall 18.

[0063] In the distance measuring device 10A, the light receiving element 16M has a substrate 31, a plurality of light detecting elements 32, and a plurality of light-transmitting plates 34 each formed on an upper surface of the light detecting elements 32. In this modification, one light detecting element 32 and the light-transmitting plate 34 on the light detecting element 32 constitute one light receiving segment 16A in the light receiving element 16M. Also, each upper surface of the light-transmitting plates 34 constitutes a light receiving surface 16S of the light receiving element 16M.

[0064] 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 a region (i.e., an inter-segment region) A1 between adjacent light-detecting elements 32 on the substrate 31 of the light-receiving element 16M. The second wall portion 18B is formed in the outermost region of the light-detecting element 32 on the substrate 31 so as to surround the entire light-detecting element 32.

[0065] In this modified example, 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.

[0066] In this modification, a light-shielding wall 18 is provided between the side surfaces of the light-detecting elements 32. Therefore, for example, after the partial tertiary light L3A is incident on the light-transmitting plate 34 toward one light-receiving segment 16A, the partial tertiary light L3A is prevented from being received by other light-receiving segments 16A than the one light-receiving segment 16A. 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.

[0067] Fig. 11 is a top view of the light receiving element 16 and the light shielding wall 19 in a distance measuring device 10B according to a second modified example of this embodiment. Fig. 12 is a cross-sectional view of the light receiving element 16 and the light shielding wall 19. Fig. 12 is a cross-sectional view taken along line 12-12 in Fig. 11, and is a cross-sectional view in the lateral direction DB of the light receiving segment 16A. Except for the configuration of the light shielding wall 19, the distance measuring device 10B has a similar configuration to that of the distance measuring device 10.

[0068] In the distance measuring device 10B, the light-shielding wall 19 has a configuration similar to that of the light-shielding wall 17, except that a second wall surface 19AS provided on the light-receiving segment 16A side of the second wall portion 19A is inclined with respect to the light-receiving surface 16S.

[0069] In this modification, each of the second wall portions 19A has a second wall surface 19AS that is provided on the light-receiving segment 16A side and forms an angle with the light-receiving surface 16S that is greater than 90°. In this modification, the second wall portions 19A of the light-shielding wall 19 have second wall surfaces 19AS that are inclined with respect to the light-receiving surface 16S so that the distance between each of the second wall portions 19A and the opposing second wall portions 19A gradually increases with increasing distance from the light-receiving surface 16S.

[0070] Since the second wall portion 19A is configured in this manner, most of the partial tertiary light L3A incident on the light-receiving segment 16A is likely to be incident on the light-shielding wall 19 before being incident on 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 optical crosstalk between the light-receiving segments 16A.

[0071] In the present embodiment and its modified examples, the light-shielding walls 17 to 19 are formed to surround the area of ​​the light-receiving segment 16A. However, the configuration of the light-shielding walls 17 to 19 is not limited to this.

[0072] For example, the light-shielding wall 17 has a first wall portion 17A provided in the inter-segment region A1, thereby suppressing optical crosstalk between the light-receiving segments 16A. Therefore, for example, the light-shielding wall 17 does not need to have the second wall portion 17B. That is, it is sufficient that the light-shielding wall 17 protrudes from the region A1 between adjacent light-receiving segments 16A on the light-receiving surface 16S of the light-receiving element 16.

[0073] In the present embodiment, for example, the case where the light-shielding wall 17 is configured to have reflectivity and scattering properties for the tertiary light L3, i.e., the primary light L1 reflected by the object OB, has been described. However, the configuration of the light-shielding wall 17 is not limited to this. For example, the light-shielding wall 17 may have absorbency for the primary light L1. For example, it is sufficient that the light-shielding wall 17 has light-shielding properties for the primary light L1.

[0074] In the present embodiment and its modified example, the light receiving segments 16A of the light receiving elements 16 and 16M are arranged in a row along the first direction D1. However, the configuration of the light receiving elements 16 and 16M is not limited to this.

[0075] For example, the light receiving element 16 may have a light receiving surface 16S on which a plurality of light receiving segments 16A are arranged. The light collecting optical system 15 may be configured to collect the tertiary light L3 and guide it to each of the light receiving segments 16A.

[0076] In other words, for example, the distance measuring device 10 may include a light receiving element 16 that receives tertiary light L3 and has a light receiving surface 16S on which a plurality of light receiving segments 16A are arranged, a focusing optical system 15 that focuses the tertiary light L3 and guides it to each of the light receiving segments 16A, and a light-shielding wall 17 that protrudes from an area A1 between adjacent light receiving segments 16A on the light receiving surface 16S of the light receiving element 16 and has a light-shielding property against the primary light L1.

[0077] This makes it possible to simultaneously project and receive the secondary light L2 onto and from a plurality of regions within the scanning region R0 while suppressing optical crosstalk between the light receiving segments 16A. This makes it possible to provide a distance measuring device 10 capable of performing accurate distance measuring operations.

[0078] In consideration of performing an accurate light receiving operation, for example, it is preferable that the wall surface 17S of the light-shielding wall 17 is configured to reflect or scatter the primary light L1. In consideration of suppressing reception of stray light and the like in the device other than the tertiary light L3, it is preferable that the light-shielding wall 17 has a second wall portion 17B, that is, the light-shielding wall 17 is formed so as to surround the outer edge region of each of the light-receiving segments 16A on the light-receiving surface 16S.

[0079] Moreover, by arranging the light-collecting optical system 15 so as to collect the tertiary light L3 at a position P1 spaced apart from the light-receiving surface 16S, the tertiary light L3 can be made incident on the entire light-receiving segment 16A. In these cases, it is particularly effective to use a light-receiving element 16 whose light detection accuracy differs depending on the area of ​​light incident on its detection surface, such as an avalanche photodiode operating in Geiger mode, as the light-detecting element 32.

[0080] In the present embodiment, the light source 11 emits laser light having a line-shaped cross-sectional shape as the primary light L1. However, the configuration of the light source 11 is not limited to this. For example, the light source 11 may emit light having any cross-sectional shape as the primary light L1. That is, the light source 11 may be configured to emit the primary light L1.

[0081] Thus, in this embodiment, the distance measuring device 10 includes a light source 11 that emits primary light L1, a deflection element 13 that deflects the primary light L1 in a variably directional manner and emits it as secondary light L2, a light receiving element 16 that receives tertiary light L3 reflected from the secondary light L2 by the object OB and has a light receiving surface 16S on which a plurality of light receiving segments 16A are arranged, a focusing optical system 15 that focuses the tertiary light L3 and guides it to each of the light receiving segments 16A, a light-shielding wall 17 that protrudes from the area A1 between adjacent light receiving segments 16A on the light receiving surface 16S of the light receiving element 16 and has a light-shielding property against the primary light L1, and a distance measuring unit 23 that measures the distance to the object OB based on the result of receiving the tertiary light L3 by the light receiving element 16.

[0082] Therefore, it is possible to provide a distance measuring device 10 that can perform accurate distance measurement by suppressing optical crosstalk between the multiple light receiving segments 16A and accurately projecting and receiving light onto the scanning region R0.

[0083] 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 does not have to have the deflection element 13. That is, the distance measuring device 10 may be configured to emit the primary light L1 in a predetermined direction and receive the primary light L1 reflected by the object OB. Even in this case, it is possible to suppress optical crosstalk between the light receiving segments 16A of the light receiving element 16, and to perform accurate distance measurement. That is, the distance measuring device 10 only needs to be configured to project and receive the primary light L1 by the light source 11 and the light receiving element 16.

[0084] Furthermore, the result of receiving the tertiary light L3 by the light receiving element 16 can be effectively used for purposes other than distance measurement, such as for detecting an object OB. Therefore, the distance measuring device 10 does not need to have the distance measuring unit 24. In this case, for example, the light source 11, the light receiving element 16, the light collecting optical system 15, and the light blocking wall 17 in the distance measuring device 10 function as a light projecting and receiving device.

[0085] Thus, in this embodiment, the distance measuring device 10 includes a light source 11 that emits primary light L1, a light receiving element 16 that receives tertiary light L3 resulting from the primary light L1 being reflected by an object OB and has a light receiving surface 16S on which a plurality of light receiving segments 16A are arranged, a light collecting optical system 15 that collects the tertiary light L3 and guides it to each of the light receiving segments 16A, and a light shielding wall 17 that protrudes from an area A1 between adjacent light receiving segments 16A in the light receiving surface 16S of the light receiving element 16 and has light shielding properties against the primary light L1. Therefore, it is possible to provide a light projecting and receiving device that can suppress optical crosstalk between the plurality of light receiving segments 16A in the light receiving element 16 and perform accurate light projecting and receiving. EXAMPLES

[0086] 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 embodiment 2. Fig. 14 is a cross-sectional view of the light receiving element 16, the light blocking wall 17, and the scattering plate 41. Fig. 14 is a cross-sectional view taken along the line 14-14 in Fig. 13.

[0087] The distance measuring device 40 has a configuration similar to that of the distance measuring device 10, except that it has a scattering plate 41 consisting of a plurality of scattering segments 41A that are provided in each of the spaces above the light receiving surface 16S defined by the light-shielding wall 17 and scatter the tertiary light L3.

[0088] 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. Also, in this embodiment, each of the scattering segments 41A is disposed in the light-shielding wall 17 along the entire optical path of the tertiary light L3 to the light-receiving segment 16A.

[0089] 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 optical crosstalk between the light receiving segments 16A while allowing the entire light receiving segment 16A to receive the tertiary light L3. This improves the reception accuracy of the tertiary light L3 for each light receiving segment 16A and for the entire light receiving element 16.

[0090] In this embodiment, the scattering plate 41 is formed on the wall surface 17S of the light-shielding wall 17, i.e., the side wall surface of the light-shielding wall 17. However, the scattering plate 41 may be formed on the end surface of the light-shielding wall 17. The scattering plate 41 only needs to be provided on the optical path of the tertiary light L3 between the light-collecting optical system 15 and each of the light-receiving segments 16A, which is defined by the light-shielding wall 17. For example, the scattering plate 41 only needs to be provided in the space above the light-receiving surface 16S, which is defined by the light-shielding wall 17.

[0091] In this way, the distance measuring device 40 has a scattering plate 41 that is provided on the optical path of the tertiary light L3 between the light collecting optical system 15 defined by the light-shielding wall 17 and each of the light receiving segments 16A and scatters the tertiary light L3. Therefore, it is possible to provide a light projecting and receiving device capable of accurate light projection and reception and a distance measuring device 40 capable of accurate distance measurement, which suppresses optical crosstalk between the multiple light receiving segments 16A in the light receiving element 16. [Explanation of symbols]

[0092] 10, 10A, 10B, 40 range finder 16, 16M photodetector 17, 18, 19 Blackout walls 41 Scatter plate

Claims

[Claim 1] A light source that emits light; The light is projected toward an object and reflected light reflected by the object is received; a light receiving element having a light receiving surface on which a plurality of light receiving segments are arranged; a focusing optical system that focuses the reflected light and guides it to each of the plurality of light receiving segments; The light receiving element has a light receiving surface that protrudes from an area between the adjacent light receiving segments. and a light-shielding wall having a light-shielding property against the light.

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