Light receiving and projection device

Abstract

The present invention provides a light-emitting and receiving device that suppresses light crosstalk between multiple light-receiving segments, enabling accurate light emission and reception, and a distance measuring device that enables accurate distance measurement. [Solution] The distance measuring device comprises a light source that emits light, a light-receiving element that receives reflected light projected toward an object and 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 concentrates the reflected light and guides it to each of the plurality of light-receiving segments, and a light-shielding wall that protrudes from the region between adjacent light-receiving segments on the light-receiving surface of the light-receiving element and has light-shielding properties.

Description

Technical Field

[0001] The present invention relates to a light transmitting and receiving device that transmits and receives light, and a distance measuring device that performs optical distance measurement.

Background Art

[0002] Conventionally, a distance measuring device that measures the distance to an object by irradiating the object with light and detecting the light reflected by the object is known. The distance measuring device includes a light transmitting and receiving device that transmits and receives light, and a distance measuring unit that generates distance measurement information based on the light transmitting and receiving result by the light transmitting and receiving device. For example, Patent Document 1 discloses an optical radar device including a light transmitting unit, a light receiving unit, and distance measuring means.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems 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 the light reflected by an object. Also, 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 light transmission and reception for each of a plurality of regions (such as a plurality of objects or a plurality of surface regions of the object).

[0005] Here, considering accurately performing light transmission and reception and distance measurement for each of the plurality of regions, for example, it is preferable that only the light returning from one region corresponding to one of the plurality of light receiving segments among the plurality of light receiving segments is received by that one light receiving segment.

[0006] Therefore, it is preferable, for example, that light returning from multiple regions is not received by one light-receiving segment, 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 light crosstalk between multiple light-receiving segments is suppressed.

[0007] The present invention has been made in view of the above-mentioned points, and one of its objectives is to provide a light-emitting and receiving device that can suppress light crosstalk between multiple light-receiving segments and perform accurate light emission and reception, and a distance measuring device that can perform accurate distance measurement. [Means for solving the problem]

[0008] The light-emitting and receiving device according to claim 1 is characterized by comprising: a light source that emits light; a light-receiving element that receives reflected light projected toward an object and 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 concentrates the reflected light and guides it to each of the plurality of light-receiving segments; and a light-shielding wall that protrudes from the region between adjacent light-receiving segments on the light-receiving surface of the light-receiving element and has light-shielding properties. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows the overall configuration of the distance measuring device according to Example 1. [Figure 2] This figure shows the light emission surface of the light source in the distance measuring device according to Example 1. [Figure 3] This figure shows an example of the configuration of the projected light in the distance measuring device according to Example 1. [Figure 4] This figure shows the light-receiving element and light-shielding wall in the distance measuring device according to Example 1. [Figure 5A] This figure shows the path of reflected light to the focusing optical system in the distance measuring device according to Example 1. [Figure 5B] This figure shows an example of the arrangement of the light-gathering optical system, light-receiving element, and light-shielding wall in the distance measuring device according to Example 1. [Figure 6]This is a top view of the light-receiving element and light-shielding wall in the distance measuring device according to Example 1. [Figure 7] This is a cross-sectional view of the light-receiving element and the light-shielding wall in the distance measuring device according to Example 1. [Figure 8] This is a cross-sectional view of the light-receiving element and the light-shielding wall in the distance measuring device according to Example 1. [Figure 9] This figure shows the path of reflected light in the distance measuring device according to Example 1. [Figure 10] This is a cross-sectional view of the light-receiving element and the light-shielding wall in a distance measuring device according to a modified example 1 of Example 1. [Figure 11] This is a top view of the light-receiving element and light-shielding wall in a distance measuring device according to a modified example 2 of Example 1. [Figure 12] This is a cross-sectional view of the light-receiving element and the light-shielding wall in a distance measuring device according to a modified example 2 of Example 1. [Figure 13] This is a top view of the light-receiving element and light-shielding wall in the distance measuring device according to Example 2. [Figure 14] This is a cross-sectional view of the light-receiving element and the light-shielding wall in the distance measuring device according to Example 2. [Modes for carrying out the invention]

[0010] Examples of the present invention will be described in detail below. [Examples]

[0011] Figure 1 is a schematic arrangement diagram of the distance measuring device 10 according to Embodiment 1. The distance measuring device 10 is a scanning type distance measuring device that performs optical scanning of a predetermined area (hereinafter referred to as the scanning area) R0 and measures the distance to an object OB located within the scanning area R0. The distance measuring device 10 will be explained using Figure 1. Figure 1 schematically shows 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 primary light L1 and emits it intermittently.

[0013] The distance measuring device 10 has a shaping optical system (or light projecting optical system) 12 that shapes the primary light L1 for light projection. The shaping optical system 12 includes, for example, at least one lens that condenses the primary light L1 while determining 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 direction-variable manner and projects it as projected 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 deflection element 13 emits the primary light L1 while bending its traveling direction and periodically changes the bending direction. The primary light L1 deflected by the deflection element 13 is projected as the secondary light L2 toward the scanning region R0.

[0015] In the present embodiment, the deflection element 13 has at least one rotating mirror 13A that rotates around 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 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 the present embodiment, the secondary light L2 is the primary light L1 reflected by the rotating mirror 13A of the deflection element 13.

[0016] Note that the scanning region R0 is a virtual three-dimensional space where the primary light L1 (secondary light L2) that has passed through the deflection element 13 is projected. Also, 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 rotating mirror 13A as the primary light L1.

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

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

[0019] Furthermore, when a virtual plane R1 is defined as a plane located a predetermined distance from the deflection element 13 within the scanning region R0, the scanning plane R1 can be defined as a two-dimensional region extending along the first and second directions D1 and D2. The secondary light L2 is projected toward the scanning region R0 so as to scan this scanning plane R1.

[0020] Furthermore, as shown in Figure 1, if an object OB (i.e., an object or substance that reflects or scatters the secondary light L2) is present in the scanning region R0, the secondary light L2 is reflected or scattered by the object OB. A portion of the secondary light L2 reflected by the object OB travels as tertiary light (i.e., reflected or backlight) L3 along almost 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 is provided on the optical path of the third-order light L3, and in this embodiment, on the optical path common to the first-order light L1 and the third-order light L3 between the deflection element 13 and the light projection optical system 12, and has a deflection element (second deflection element) 14 that deflects the third-order light L3. For example, the deflection element 14 is an optical separation element that separates the first-order light L1 and the third-order light L3 by transmitting the first-order light L1 and reflecting the third-order light L3, and in this embodiment, it is a beam splitter.

[0022] In this embodiment, the deflection element 13 is a movable deflection element for scanning that deflects the primary light L1 in a variable direction when it operates. On the other hand, the deflection element 14 is a fixed deflection element for separating the primary light L1 and the tertiary light L3.

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

[0024] The distance measuring device 10 is installed on the optical path of the third-order light L3 focused by the focusing optical system 15 and has a light-receiving element 16 that receives the third-order light L3. For example, the light-receiving element 16 detects the third-order light L3 and generates an electrical signal corresponding to the third-order light L3.

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

[0026] The distance measuring device 10 has a light-shielding wall 17 provided 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 that generated by the projection of third-order light L3, i.e., second-order light L2, onto the scanning area R0 (object OB), onto the light-receiving element 16. Details of the light-receiving element 16 and the light-shielding wall 17 will be described 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] Furthermore, the control unit 20 has a distance measuring unit 23 that drives the light-receiving element 16 and measures the distance to the target object OB based on the light-receiving result of the third-order light L3 by the light-receiving element 16. In this embodiment, the distance measuring unit 23 detects a pulse indicating the third-order light L3 from the electrical signal generated by the light-receiving element 16. The distance measuring unit 23 also measures the distance to the target object OB (or a part of its surface area) using the time-of-flight method based on the time difference between the light emission timing of the second-order light L2 and the light-receiving timing of the third-order 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 of the scanning area R0 (distance measuring image) that shows the distance measurement result (distance value) of each of the plurality of distance measuring points as pixels. In this embodiment, the distance measuring unit 23 associates information indicating the distance measuring points with the displacement of the rotating mirror 13A and generates image data showing a two-dimensional map or a three-dimensional map of the scanning area R0.

[0030] Furthermore, the distance measuring unit 23 uses, for example, the period of change in the projection direction of the secondary light L2, i.e., the scanning period which is the period of scanning the scanning area R0, as the generation period for the distance measuring image, and generates one distance measuring image for each scanning period.

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

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

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

[0034] Figure 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 single 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 performs the light-receiving operation of the third-order light L3 independently of each other. Furthermore, each of the light-receiving segments 16A has a detection element that performs light detection using at least one photoelectric conversion element.

[0036] Next, in this embodiment, the light-shielding wall 17 is formed on the light-receiving surface 16S such that it protrudes from the light-receiving surface 16S of the light-receiving element 16. For example, the surface of the light-shielding wall 17 is reflective or scatterable with respect to the third-order light L3. In this embodiment, the surface of the light-shielding wall 17 is reflective and scatterable with respect to the third-order light L3.

[0037] In this embodiment, the light-shielding wall 17 is formed 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 grid pattern so that multiple unit cells are arranged on the light-receiving surface 16S of the light-receiving element 16.

[0038] In the following, 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 of the light-receiving segments 16A (or the length direction of the light-receiving surface 16S) DA. Furthermore, 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 of the light-receiving segments 16A (or the 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 lateral direction DB corresponds to the second direction D2.

[0039] Figure 5A schematically shows the spot shape of the secondary light L2 irradiated onto 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 Figure 5A, the region of the object OB irradiated with the secondary light L2 has a linear shape with the first direction D1 as its longitudinal direction. Then, light with various incidence angles enters the focusing optical system 15 from the irradiated region of the object OB with the secondary light L2 as tertiary light L3.

[0040] Figure 5B schematically shows the arrangement between the focusing 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 to extend perpendicularly to the optical axis of the focusing optical system 15.

[0041] Furthermore, the third-order light L3 incident on the focusing optical system 15 can be divided into multiple partial light beams (hereinafter referred to as partial third-order light beams) L3A depending on the angle of incidence to the focusing optical system 15. Each of these partial third-order light beams L3A becomes light that is received by each of the light-receiving segments 16A, as shown in Figure 5B.

[0042] For example, among the multiple partial light beams L3A, the partial light beam L3AA traveling along a direction parallel to the optical axis of the focusing optical system 15 (i.e., the component with an incident angle of 0 degrees in the third light beam L3) 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 received partial third-order light L3A is generated by each of the light-receiving segments 16A. Consequently, when the area in the scanning region R0 where the second-order light L2 is projected at one time is divided along the first direction D1 into multiple sub-regions corresponding to each of the light-receiving segments 16A, scanning information for these sub-regions is acquired all at once. Furthermore, by repeating this process along the second direction D2, scanning information for the entire scanning region R0 is acquired.

[0044] Furthermore, in this embodiment, the light-shielding wall 17 protrudes from the light-receiving surface 16S toward the light-collecting optical system 15, along 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] Furthermore, in this embodiment, the condensing optical system 15 is arranged such that the third-order light L3 (reflected light) is focused at a position (focal position) P1 that is spaced apart from the light-receiving surface 16S of the light-receiving element 16. Specifically, for example, if the condensing optical system 15 has at least one lens, and the position of the lens is taken as position P0, then the light-receiving surface 16S of the light-receiving element 16 is positioned further away from the lens than position P1, which is spaced at the focal length LF of the lens.

[0046] In this embodiment, the focusing optical system 15 is arranged so that the third-order light L3 is focused within the space on the light-receiving surface 16S defined by the light-shielding wall 17. Therefore, as shown in Figure 5, the third-order light L3 (each of the partial third-order light L3A) is incident on each of the light-receiving segments 16A of the light-receiving element 16 without being fully focused.

[0047] Figure 6 is a top view of the light-receiving element 16 and the light-shielding wall 17. As shown in Figure 6, in the light-receiving element 16, the light-receiving segments 16A are arranged spaced apart from each other. Therefore, the light-receiving surface 16S of the light-receiving element 16 has a region A0 in which the light-receiving segments 16A are formed (hereinafter referred to as the segment region) and a region A1 between adjacent light-receiving segments 16A (hereinafter referred to as the inter-segment region).

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

[0049] Figures 7 and 8 are cross-sectional views of the light-receiving element 16 and the light-shielding wall 17, respectively. Figures 7 and 8 are cross-sectional views along lines 7-7 and 8-8 in Figure 6, respectively. Figure 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 segment 16A. Figure 8 is a cross-sectional view of the light-receiving element 16 and the light-shielding wall 17 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 includes a substrate 31, a plurality of photodetectors 32 arranged side by side on the substrate 31, and a light-transmitting plate 33 integrally formed on the substrate 31 so as to cover the entire upper surface of the plurality of photodetectors 32.

[0051] Each of the photodetectors 32 has at least one photoelectric conversion element that performs photoelectric conversion for the third light L3. In this embodiment, each of the photodetectors 32 includes at least one avalanche photodiode operating in Geiger mode. In this embodiment, the light-transmitting plate 33 has a flat shape and is light-transmitting to the third light L3.

[0052] In this embodiment, as shown in Figure 7, one photodetector 32 and the portion of the light-transmitting plate 33 on the photodetector 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 the light-receiving surface 16S of the light-receiving element 16.

[0053] Furthermore, 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. The wall surface 17S of the light-shielding wall 17 (see Figure 5) has a first wall surface 17AS provided on the segment region A0 side of the first wall portion 17A, and a second wall surface 18BS provided on the segment region A0 side of the second wall portion 17B.

[0054] For example, in the examples shown in Figures 6 to 8, the first wall portion 17A of the light-shielding wall 17 has a thickness equal to or less than the spacing between segments in the inter-segment region A1 (the distance between adjacent photodetectors 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 greater than the spacing between segments in the inter-segment region A1. The light-shielding wall 17 will be formed slightly above the segment region A0.

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

[0056] Furthermore, the third-order light L3 (partial third-order light L3A) incident within a single space defined by the light-shielding wall 17 is light that should be received by a single light-receiving segment 16A corresponding to that space. The light-shielding wall 17 prevents the third-order light L3 incident within that space from traveling to other spaces. Therefore, partial third-order light L3A that should be received by one light-receiving segment 16A is received by other light-receiving segments 16A, i.e., light crosstalk between light-receiving segments 16A is suppressed.

[0057] Furthermore, in this embodiment, as shown in Figure 9, the first wall surface 17AS of the first wall portion 17A of the light-shielding wall 17 is configured to scatter third-order light L3. In this embodiment, the entire wall surface 17S of the light-shielding wall 17 is configured to scatter light. For example, the light-shielding wall 17 has been subjected to a light-scattering treatment such as unevenness on its wall surface 17S.

[0058] Therefore, the third-order light L3 (partial third-order 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 Figure 9. Furthermore, the third-order light L3 is scattered each time it is incident on the light-shielding wall 17.

[0059] This makes it easier for the third-order light L3 to be incident on the entire segment region A0. Therefore, the third-order light L3 can be received across the entire light-receiving segment 16A (photodetector element 32). This ensures reliable reception and detection of the third-order light L3.

[0060] Furthermore, in this embodiment, each of the light-receiving segments 16A has a photodetector element 32 that includes at least one avalanche photodiode operating in Geiger mode. Therefore, the larger the area to which the partial third-order light L3 is incident on the photodetector element 32, the more accurately the photodetection operation (photon counting) can be performed. Conversely, because the light-shielding wall 17 has light-scattering properties, the partial third-order light L3 can be received across the entire light-receiving segment 16A. Therefore, the third-order light L3 can be received and detected more accurately.

[0061] In this embodiment, the case described is one in which the light-receiving element 16 is integrally formed on a light-transmitting plate 33, and the light-shielding wall 17 is formed on the light-transmitting plate 33. However, the configuration of the light-receiving element 16 and the light-shielding wall 17 is not limited to this.

[0062] Figure 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 Modification 1 of this embodiment. Figure 10 is a cross-sectional view of the light-receiving element 16M and the light-shielding wall 18 similar to that in Figure 7. The distance measuring device 10A has the same configuration as the distance measuring device 10, except for the configuration of the light-receiving element 16M and the light-shielding wall 18.

[0063] In the distance measuring device 10A, the light-receiving element 16M includes a substrate 31, a plurality of photodetectors 32, and a plurality of light-transmitting plates 34, each formed on the upper surface of a photodetector 32. In this modified example, one photodetector 32 and the light-transmitting plate 34 on the photodetector 32 constitute one light-receiving segment 16A of the light-receiving element 16M. Furthermore, each of the upper surfaces of the light-transmitting plates 34 constitutes a light-receiving surface 16S of the light-receiving element 16M.

[0064] In this modified example, 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 adjacent photodetectors 32 on the substrate 31 of the light-receiving element 16M (i.e., the inter-segment region). The second wall portion 18B is formed in the outermost region of the photodetector 32 on the substrate 31, surrounding the entire photodetector 32.

[0065] In this modified example, the first and second wall portions 18A and 18B of the light-shielding wall 18 are formed beyond the upper surface of the substrate 31 and beyond the light-receiving surface 16S, thereby protruding from the light-receiving surface 16S.

[0066] In this modified example, a light-shielding wall 18 is provided between the sides of the photodetector element 32. Therefore, for example, after partial third-order light L3A is incident on the light-transmitting plate 34 toward one light-receiving segment 16A, it is suppressed that the partial third-order light L3A is received by another light-receiving segment 16A other than the first light-receiving segment 16A. Therefore, the effect of suppressing crosstalk between light-receiving segments 16A is significant. The light-shielding wall 18 may be provided in this manner.

[0067] Figure 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 a modified example 2 of this embodiment. Figure 12 is a cross-sectional view of the light-receiving element 16 and the light-shielding wall 19. Figure 12 is a cross-sectional view along the line 12-12 in Figure 11, and is a cross-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.

[0068] In the distance measuring device 10B, the light-shielding wall 19 has the same configuration as the light-shielding wall 17, except that the 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 modified example, each of the second wall portions 19A is provided on the light-receiving segment 16A side and has a second wall surface 19AS that is greater than 90° in angle with respect to the light-receiving surface 16S. In this modified example, the second wall portion 19A of the light-shielding wall 19 has a second wall surface 19AS that is inclined with respect to the light-receiving surface 16S such that the distance from the other opposing second wall portion 19A gradually increases as it moves away from the light-receiving surface 16S.

[0070] With the second wall 19A configured in this way, most of the partial third-order light L3A incident on the light-receiving segment 16A is more likely to be incident on the light-shielding wall 19 before it enters the light-receiving segment 16A. Therefore, the partial third-order light L3A can be reflected and scattered and guided to the entire light-receiving segment 16A. Thus, the third-order light L3 can be accurately received by the light-receiving segment 16A while suppressing light crosstalk between the light-receiving segments 16A.

[0071] In this embodiment and its modifications, the case in which the light-shielding walls 17 to 19 are formed to surround the area 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.

[0072] For example, the light-shielding wall 17 can suppress light crosstalk between light-receiving segments 16A by having a first wall portion 17A provided in the inter-segment region A1. Therefore, for example, the light-shielding wall 17 does not need to have a second wall portion 17B. That is, the light-shielding wall 17 only needs to protrude from the region A1 between adjacent light-receiving segments 16A on the light-receiving surface 16S of the light-receiving element 16.

[0073] Furthermore, in this embodiment, for example, a case has been described in which the light-shielding wall 17 is configured to have reflectivity and scattering properties with respect to the third light L3, that is, the primary light L1 reflected by the object OB. However, the configuration of the light-shielding wall 17 is not limited to this. For example, the light-shielding wall 17 may have absorbing properties with respect to the primary light L1. For example, the light-shielding wall 17 only needs to have light-shielding properties with respect to the primary light L1.

[0074] Furthermore, in this embodiment and its modifications, the case in which the light-receiving segments 16A of the light-receiving elements 16 and 16M are arranged in a single row along the first direction D1 has been described. However, the configuration of the light-receiving elements 16 and 16M is not limited thereto.

[0075] For example, the light-receiving element 16 may have a light-receiving surface 16S on which multiple light-receiving segments 16A are arranged. The focusing optical system 15 may be configured to focus the third-order light L3 and guide it to each of these light-receiving segments 16A.

[0076] In other words, for example, the distance measuring device 10 only needs to include a light-receiving element 16 that receives third-order 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 third-order light L3 and guides it to each of the light-receiving segments 16A, and a light-shielding wall 17 that protrudes from the region A1 between adjacent light-receiving segments 16A within the light-receiving surface 16S of the light-receiving element 16 and has light-shielding properties against the primary light L1.

[0077] This allows for simultaneous transmission and reception of secondary light L2 to multiple regions within the scanning region R0 while suppressing optical crosstalk between light-receiving segments 16A. This enables the provision of a distance measuring device 10 capable of accurate distance measurement.

[0078] Furthermore, considering the need for accurate light reception, it is preferable that the wall surface 17S of the light-shielding wall 17 is configured to reflect or scatter the primary light L1. Also, considering the need to suppress the reception of stray light and other light sources within the device besides the tertiary light L3, it is preferable that the light-shielding wall 17 has a second wall portion 17B, that is, that the light-shielding wall 17 is formed to surround the outer edge regions of each of the light-receiving segments 16A on the light-receiving surface 16S.

[0079] Furthermore, by arranging the focusing optical system 15 to focus the third-order light L3 at a position P1 spaced apart from the light-receiving surface 16S, the third-order light L3 can be incident on the entire light-receiving segment 16A. In these cases, the effect is particularly significant when using a light-receiving element 16 such as an avalanche photodiode operating in Geiger mode as the photodetector element 32, where the photodetection accuracy differs depending on the area of ​​light incident on the detection surface.

[0080] Furthermore, in this embodiment, the case in which the light source 11 emits laser light with a 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 can emit light with any cross-sectional shape as the primary light L1. In other words, the light source 11 only needs to be configured to emit primary light L1.

[0081] As described above, 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 variable direction and emits it as secondary light L2, a light receiving element 16 that receives tertiary light L3 reflected by the object OB from the secondary light L2 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 region A1 between adjacent light receiving segments 16A within the light receiving surface 16S of the light receiving element 16 and has light-shielding properties against the primary light L1, and a distance measuring unit 23 that measures the distance to the object OB based on the light receiving result of the tertiary light L3 by the light receiving element 16.

[0082] Therefore, by suppressing light crosstalk between multiple light-receiving segments 16A and performing accurate light transmission and reception with respect to the scanning area R0, a distance measuring device 10 can be provided that can perform accurate distance measurement.

[0083] In this embodiment, the case in which the distance measuring device 10 has a deflection element 13 has been described. However, the distance measuring device 10 does not have to have a deflection element 13. That is, the distance measuring device 10 may be configured to emit primary light L1 in a predetermined direction and receive the primary light L1 reflected by the object OB. Even in this case, crosstalk of light between the receiving segments 16A of the light receiving element 16 can be suppressed, and accurate distance measurement can be performed. In other words, the distance measuring device 10 only needs to be configured to emit and receive primary light L1 using the light source 11 and the light receiving element 16.

[0084] Furthermore, the light reception result of the third-order light L3 by the light-receiving element 16 can be effectively used for purposes other than distance measurement, such as detecting an object OB. Therefore, the distance measuring device 10 does not necessarily have a distance measuring unit 24. In this case, for example, the light source 11, light-receiving element 16, light-collecting optical system 15, and light-shielding wall 17 in the distance measuring device 10 function as a light-emitting and light-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 reflected by the object OB from the primary light L1 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 the region A1 between adjacent light-receiving segments 16A within the light-receiving surface 16S of the light-receiving element 16 and has light-shielding properties from the primary light L1. Therefore, it is possible to provide a light-transmitting and receiving device that can suppress light crosstalk between the plurality of light-receiving segments 16A in the light-receiving element 16 and perform accurate light transmission and reception. [Examples]

[0086] Figure 13 is a top view of the light-receiving element 16, light-shielding wall 17, and scattering plate 41 in the distance measuring device 40 according to Embodiment 2. Figure 14 is a cross-sectional view of the light-receiving element 16, light-shielding wall 17, and scattering plate 41. Figure 14 is a cross-sectional view along the line 14-14 in Figure 13.

[0087] The distance measuring device 40 has the same configuration as the distance measuring device 10, except that it 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 consisting of a plurality of scattering segments 41A that scatter the third 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. In this embodiment, each of the scattering segments 41A is arranged along the entire optical path of the third light L3 to the light-receiving segment 16A within the light-shielding wall 17.

[0089] Therefore, as shown in Figure 14, the third-order light L3 is scattered by the scattering plate 41 and then received by the light-receiving segment 16A of the light-receiving element 16. Thus, the light-shielding wall 17 and the scattering plate 41 suppress light crosstalk between the light-receiving segments 16A, while allowing the third-order light L3 to be received across the entire light-receiving segment 16A. Consequently, the accuracy of receiving the third-order light L3 for each individual light-receiving segment 16A and for the entire light-receiving element 16 is improved.

[0090] In this embodiment, the case in which the scattering plate 41 is formed on the wall surface 17S of the light-shielding wall 17, that is, on the side wall surface of the light-shielding wall 17, has been described. However, the scattering plate 41 may also be formed on the end face of the light-shielding wall 17. The scattering plate 41 should be provided in the optical path of the third-order light L3 between the light-collecting optical system 15 and the light-receiving segment 16A, which are defined by the light-shielding wall 17. For example, the scattering plate 41 should be provided in the space on the light-receiving surface 16S defined by the light-shielding wall 17.

[0091] Thus, the distance measuring device 40 is provided on the optical path of the third-order 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 has a scattering plate 41 that scatters the third-order light L3. Therefore, crosstalk of light between the multiple light-receiving segments 16A in the light-receiving element 16 is suppressed, and a light-transmitting and receiving device capable of accurate light transmission and reception, and a distance measuring device 40 capable of accurate distance measurement can be provided. [Explanation of symbols]

[0092] 10, 10A, 10B, 40 range finder 16, 16M photodetector 17, 18, 19 Light-blocking wall 41 Scatter plate

Claims

[Claim 1] A light source that emits light, The light is projected toward the object and the reflected light reflected by the object is received. A photodetector having a light-receiving surface on which multiple light-receiving segments are arranged, A focusing optical system that collects the reflected light and guides it to each of the plurality of light-receiving segments, From the region between adjacent light-receiving segments on the light-receiving surface of the light-receiving element, A light-emitting and light-receiving device characterized by having a light-emitting and light-shielding wall that has light-shielding properties against the aforementioned light.

Images