JP2020067310A - Light emitting/receiving device and ranging device - Google Patents

Abstract

To provide a light emitting/receiving device capable of suppressing the cross talk of light between a plurality of light receiving elements and accurately emitting/receiving the light, and a ranging device capable of performing accurate ranging.SOLUTION: A light emitting/receiving device comprises: an emitting part 11 having a plurality of emission regions emitting light and having different polarization directions in lights emitted between emission regions adjacent to each other; a polarization part 18 having a plurality of polarizers provided on the optical path of reflected light formed by reflecting the light emitted from the emitting part on an object and having different polarization directions in lights transmitted between the polarizers adjacent to each other; and a light receiving part 19 having a plurality of light receiving elements for light-receiving the lights transmitting the plurality of polarizers of the polarization part, respectively.SELECTED DRAWING: Figure 1

Description

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

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

JP 2007-85832

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

  Here, considering that light projection / light reception and distance measurement are accurately performed on each of the plurality of regions, for example, one light receiving element of the plurality of light receiving elements has one of the plurality of regions. It is preferable that only the light returning from the region 1 corresponding to the one light receiving element is received.

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

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

  The invention according to claim 1 has a plurality of emission regions for emitting light, and an emission part in which the polarization directions of the light emitted between adjacent emission regions are different, and the light emitted from the emission part is the object. Each of the plurality of polarizers having a plurality of polarizers provided on the optical path of the reflected light reflected by and having different polarization directions of light transmitted between adjacent polarizers And a light-receiving portion having a plurality of light-receiving elements that respectively receive the light that has passed through.

  The invention according to claim 7 includes the light emitting and receiving device according to claim 1, and a distance measuring unit that measures a distance to an object based on a light reception result of reflected light by the light receiving unit. Characterize.

FIG. 1 is a diagram showing an overall configuration of a distance measuring device according to a first embodiment. FIG. 3 is a diagram showing a light emitting surface of a light source in the distance measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing a configuration of an emission unit in the distance measuring device according to the first embodiment. FIG. 3 is a diagram illustrating upper surfaces of a light receiving unit and a polarization unit in the distance measuring device according to the first embodiment. 5A and 5B are diagrams illustrating light before and after incidence of a polarization unit in the distance measuring apparatus according to the first embodiment. FIG. 6 is a diagram showing a configuration of an emission unit in a distance measuring device according to a modified example of the first embodiment. FIG. 6 is a diagram showing a configuration of an emission unit in the distance measuring device according to the second embodiment.

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

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

  First, the distance measuring device 10 has an emission unit 11 that generates and emits light that is projected toward the scanning region R0. First, the emission unit 11 has a light source 12 that emits light (hereinafter, referred to as primary light) L1. In this embodiment, the light source 12 generates laser light having a peak wavelength in the infrared region as the primary light L1 and intermittently emits it.

  The emission unit 11 has an imaging optical system 13 that forms an image showing the beam shape of the primary light L1, that is, an image of the emission surface of the primary light L1 in the light source 12. The imaging optical system 13 includes, for example, a relay lens.

  The emission unit 11 is provided on the optical path of the primary light L1 and adjusts the polarization component of the primary light L1 to emit light (hereinafter, referred to as secondary light L2) L2 having different polarization directions between adjacent regions. It has an optical plate 14 for emitting light. The optical plate 14 has, for example, wave plates or polarizers arranged in an array. In the present embodiment, the optical plate 14 is arranged at a position where the image of the primary light L1 is formed by the image forming optical system 13.

  The emission part 11 has an emission optical system 15 for emitting the secondary light L2 while shaping it. The emission optical system 15 includes, for example, at least one lens that collects the secondary light L2 and shapes the cross-sectional shape of the secondary light L2. The emission unit 11 emits the secondary light L2 emitted from the emission optical system 15 as light for projecting toward the scanning region R0.

  The distance measuring device 10 includes a deflection unit (first deflection unit) 16 that deflects the secondary light L2 emitted from the emission unit 11 in a variable direction and projects the secondary light L2 as the tertiary light L3. The deflecting unit 16 performs a periodic operation to periodically change the deflection direction of the secondary light L2. The deflecting unit 16 bends the traveling direction of the secondary light L2 while emitting the secondary light L2, and periodically changes the bending direction. The secondary light L2 deflected by the deflecting unit 16 is projected as the tertiary light L3 toward the scanning region R0.

  In the present embodiment, the deflection unit 16 has at least one rotating mirror 16A that rotates around the rotation axis AY and reflects the secondary light L2. For example, the deflection unit 16 includes a polygon mirror. In the present embodiment, the deflecting unit 16 periodically changes the reflection direction of the secondary light L2 by reflecting the secondary light L2 while the rotating mirror 16A rotates. That is, in this embodiment, the tertiary light L3 is the secondary light L2 reflected by the turning mirror 16A of the deflecting unit 16.

  The scanning region R0 is a virtual three-dimensional space in which the secondary light L2 (third light L3) that has passed through the deflection unit 13 is projected. In addition, in the present embodiment, the emitting unit 11 emits laser light having a linear cross-sectional shape extending along the axial direction of the rotation axis AY of the rotation mirror 16A as the secondary light L2.

  In FIG. 1, the outer edge of the scanning region R0 is schematically shown by a broken line. Further, in FIG. 1, the main optical axes of the primary light L1 to the tertiary light L3 are shown by solid lines, and the optical paths of the ends of the primary light L1 and the secondary light L2 along the axial direction of the rotation axis AY are shown. It is shown by a broken line.

  For example, the scanning region R0 includes a height direction direction range along a longitudinal direction (hereinafter, referred to as a first direction) D1 in a cross section of the tertiary light L3, and a deflection direction of the secondary light L2 by the deflection unit 16. A widthwise direction range along a direction (hereinafter, referred to as a second direction) D2 corresponding to the variable range and a distance direction range (that is, a depth range) in which the tertiary light L3 can maintain a predetermined intensity. Can be defined as a conical space having.

  When a virtual plane distant from the deflecting unit 16 within the scanning region R0 by a predetermined distance is defined as the scanning surface R1, the scanning surface R1 is two-dimensionally spread along the first and second directions D1 and D2. Can be defined as an area. The tertiary light L3 is projected toward the scanning region R0 so as to scan the scanning surface R1.

  Further, as shown in FIG. 1, when an object OB (that is, an object or a substance having a reflectivity or a scattering property with respect to the third-order light L3) exists in the scanning region R0, the third-order light L3 changes to the object OB. Is reflected or scattered by. The third-order light L3 reflected by the object OB has a part of the third-order light L3 as a fourth-order light (that is, reflected light or return light) L4, and has an optical path substantially the same as that of the third-order light L3 opposite to the third-order light L3. It proceeds in the direction and returns to the deflection unit 16.

  The distance measuring device 10 is provided on the optical path of the quaternary light L4, in the present embodiment, on the optical path common to the secondary light L2 and the quaternary light L4 between the deflection unit 16 and the emission optical system 15. It has a deflection unit (second deflection unit) SP that deflects the next light L4. For example, the deflecting unit SP is a light separating element that separates the secondary light L2 and the quaternary light L4 by transmitting the secondary light L2 and reflecting the quaternary light L4, and is a beam splitter in this embodiment. is there.

  In the present embodiment, the deflecting unit 16 is a movable deflecting element for scanning that deflects the secondary light L2 in a directionally variable manner by operating. On the other hand, the deflection unit SP is a fixed deflection element for separating the secondary light L2 and the quaternary light L4.

  The distance measuring device 10 has a light receiving optical system 17 that receives and collects the fourth-order light L4 deflected by the deflecting unit SP. The light receiving optical system 17 includes, for example, at least one lens.

  The distance measuring device 10 includes a polarization unit 18 provided on the optical path of the quaternary light L4 deflected by the deflection unit SP and transmitting a predetermined polarization component of the quaternary light L4. The polarization unit 18 is a plate-shaped light-transmitting member having a plurality of polarizers juxtaposed on the optical path of the fourth-order light L4. In the present embodiment, the polarization unit 18 is arranged at a position where the light receiving optical system 17 collects the fourth-order light L4.

  The distance measuring device 10 includes a light receiving unit 19 that receives the fourth-order light L4 that has passed through the polarization unit 18. The light receiving unit 19 has a plurality of light receiving elements that detect the fourth-order light L4 and generate an electrical signal according to the fourth-order light. The light receiving unit 19 generates the electric signal as a result of receiving the fourth-order light L4. That is, the distance measuring device 10 generates the electric signal generated by the light receiving unit 19 as the scanning result of the scanning region R0.

  The distance measuring device 10 includes a control unit 20 that drives and controls the emitting unit 11, the deflecting unit 16, and the light receiving unit 19. For example, in the present embodiment, the control unit 20 includes a light source control unit 21 that drives and controls the light source 12 of the emission unit 11, and a deflection control unit that drives and controls the rotating mirror 16A of the deflection unit 16. 22 and.

  The control unit 20 also includes a distance measuring unit 23 that drives the light receiving unit 19 and measures the distance to the object OB based on the light reception result of the fourth-order light L4 by the light receiving unit 19. In the present embodiment, the distance measuring unit 23 detects a pulse indicating the fourth order light L4 from the electric signal generated by the light receiving unit 19. Further, the distance measuring unit 23 uses the time-of-flight method based on the time difference between the projection timing of the tertiary light L3 and the reception timing of the quaternary light L4 to reach the object OB (or a partial surface area thereof). To measure the distance. Further, the distance measuring unit 23 generates data indicating the measured distance information (distance measuring data).

  Further, in the present embodiment, the distance measuring unit 23 distinguishes the scanning region R0 (scanning surface R1) into a plurality of distance measuring points (scanning points), and the distance measuring results (distances) of each of the plurality of distance measuring points. An image (distance-measuring image) of the scanning region R0 in which (value) is shown as a pixel is generated. In the present embodiment, the distance measuring unit 23 associates the distance measuring point with the information indicating the displacement of the rotating mirror 16A and generates image data indicating the two-dimensional map or the three-dimensional map of the scanning region R0.

  Further, the distance measuring unit 23 uses, for example, a change cycle of the projection direction of the tertiary light L3, that is, a scanning cycle that is a cycle of scanning the scanning region R0, as a distance measurement image generation cycle, and one cycle for each scanning cycle. Generate a ranging image.

  Note that the scanning cycle means, for example, a period until the predetermined displacement of the rotating mirror 16A returns to the displacement again when the distance measuring device 10 periodically performs optical scanning on the scanning region R0. Further, the distance measuring unit 23 may have a display unit (not shown) that displays a plurality of generated distance measuring images as moving images in time series.

  FIG. 2 is a diagram schematically showing the light emitting surface 12S of the light source 12. In the present embodiment, the light source 12 has a laser element 12A that emits laser light having a linear or elliptical beam shape having the first direction D1 as the longitudinal direction as the primary light L1. In the present embodiment, the laser element 12A emits a linear laser beam having a cross-sectional shape in which the first direction D1 is the longitudinal direction and the second direction D2 is the lateral direction.

  FIG. 3 is a diagram schematically showing the cross-sectional shape of the primary light L2 immediately before entering the optical plate 14, the configuration of the optical plate 14, and the cross-sectional shape of the secondary light L2 immediately after being emitted from the optical plate 14. . In the present embodiment, the optical plate 14 causes the imaging optical system 13 to image the emission area of the primary light L1 on the light emission surface 12S of the light source 12 (hereinafter, simply referred to as the image of the light emission surface 12S) L1P. Is arranged at a position where an image is formed. FIG. 3 shows the outer edge of the image L1P.

  First, the light source 12 emits laser light including linearly polarized light along the first polarization direction PD1 as the primary light L1. For example, the primary light L1 is laser light that includes linearly polarized light having a direction along the first direction D1, which is the longitudinal direction of the primary light L1, as the first polarization direction PD1.

  Next, in the present embodiment, the optical plate 14 is provided on the optical path of the primary light L1 (laser light), and the first region 14A for transmitting the primary light L1 and the half-wave plate are formed. The second regions 14B and the transparent regions 14S are alternately arranged. In the present embodiment, the first and second regions 14A and 14B are arranged in a row as a whole in the translucent region 14S of the optical plate 14. For example, the first region 14A may be formed as an opening of the optical plate 14 or may be a region where a light transmitting plate is formed.

  Therefore, in the present embodiment, of the secondary light L2 that is the primary light L1 that has transmitted through the optical plate 14, if the light that has transmitted through the first region 14A is the first secondary light L2A, then The secondary light L2A is linearly polarized light along the same first polarization direction PD1 as the primary light L1.

  On the other hand, when the light transmitted through the second region 14B of the secondary light L2 is the second secondary light L2B, the polarization direction of the second secondary light L2B is 90 degrees with respect to the primary light L1. Different light. That is, the second secondary light L2B is linearly polarized light along the second polarization direction PD2 that is perpendicular to the first polarization direction PD1.

  Therefore, when the surface from which the secondary light L2 in the light projecting region 14S of the optical plate 14 is extracted is the emission surface 11S of the secondary light L2 in the emission portion 11, the emission surface 11S includes the first and second optical plates 14, respectively. Corresponding to the second regions 14A and 14B, a plurality of first and second emission regions 11A and 11B for emitting the first and second secondary lights L2A and L2B are provided. Further, the polarization directions of the secondary light L2 emitted are different between the first and second emission areas 11A and 11B adjacent to each other on the emission surface 11S.

  In other words, the distance measuring device 10 has a plurality of emission areas 11A and 11B that emit light (secondary light L2), and the emission sections 11 having different polarization directions of the emission areas 11A and 11B adjacent to each other. Have. The emission unit 11 emits the secondary light L2 including such a polarization component. Then, the secondary light L2 is projected by the deflecting unit 16 as the tertiary light L3 toward the object OB in the scanning region R0.

  FIG. 4 is a plan view showing the light receiving surface 19S of the light receiving unit 19 and the polarization region 18S of the polarization unit 18. First, in the present embodiment, the light receiving unit 19 is a light receiving unit in which a plurality of first and second light receiving elements 19A and 19B are arranged along the first direction D1 (direction corresponding to the first direction D1). It has a surface 19S. In this embodiment, a plurality of first and second light receiving elements 19A and 19B are arranged in a row on the light receiving surface 19S of the light receiving section 19 so as to be different from each other. In this embodiment, the light receiving section 19 is a line sensor having a linear light receiving surface 19S.

  In the present embodiment, each of the first and second light receiving elements 19A and 19B performs the light receiving operation of the fourth-order light L4 independently of each other. Further, each of the first and second light receiving elements 19A and 19B has a detection element that performs light detection by at least one photoelectric conversion element.

  Further, the polarization unit 18 has a plurality of first and second polarizers 18A and 18B provided on the optical path of the fourth-order light L4, and the first and second polarizers 18A and 18B are arranged. It has a polarization region 18S.

  In addition, the first polarizer 18A is configured to transmit light in the first polarization direction PD1. The second polarizer 18B is configured to transmit light in the second polarization direction PD2. Further, in the present embodiment, in the polarization region 18S of the polarization unit 18, the first and second polarizers 18A and 18B are arranged in a staggered manner in a row along a direction corresponding to the first direction D1. ing.

  FIG. 5 is a diagram showing the quaternary light L4 before passing through the polarization unit 18 and the quaternary light L4 when passing through the polarization unit 18 and entering the light receiving unit 19. FIG. 5 shows a perspective view of the polarization unit 18 and the light receiving unit 19. In addition, in the present embodiment, each of the polarization unit 18 and the light receiving unit 19 is arranged at a position where the fourth order light L4 is condensed by the light receiving optical system 17.

  First, the first polarizer 18A is arranged in the polarization region 18S at a position corresponding to the first emission region 11A of the emission unit 11, that is, the first region 14A of the optical plate 14. In addition, the second polarizer 18B is arranged in the polarization region 18S at a position corresponding to the second emission region 11B of the emission unit 11, that is, the second region 14B of the optical plate 14.

  Therefore, when the light that enters the first polarizer 18A among the fourth order light L4 is the first fourth order light L4A, the first fourth order light L4A is the first exit area 11A of the exit unit 11. The first secondary light L2A emitted from the laser corresponds to the light returned from the scanning region R0. Further, when the light that enters the second polarizer 18B among the fourth-order light L4 is the second fourth-order light L4B, the second fourth-order light L4B is the second emission area 11B of the emission unit 11. The second secondary light L2B emitted from the laser corresponds to the light returned from the scanning region R0.

  Therefore, the first fourth-order light L4A often includes a large amount of linearly polarized light along the first polarization direction PD1. In addition, the second fourth-order light L4B often includes a large amount of linearly polarized light along the second polarization direction PD2. Therefore, most of the first fourth-order light L4A passes through the first polarizer 18A. Further, most of the second fourth-order light L4B passes through the second polarizer 18B. The first and second fourth-order lights L4A and L4B that have passed through the first and second polarizers 18A and 18B of the polarization unit 18 are received by the respective light receiving elements 19A of the light receiving unit 19.

  Further, in the present embodiment, each of the first and second light receiving elements 19A and 19B is arranged in the light receiving surface 19S at a position corresponding to one polarizer 18A or 18B of the polarization unit 18. Therefore, in the example shown in FIG. 5, the first fourth-order light L4A transmitted through the one first polarizer 18A is incident on the one first light receiving element 19A, and is incident on the one second light receiving element 19B. Enters the second fourth-order light L4B that has passed through one second polarizer 18B.

  Further, in the present embodiment, the second light receiving element 19B adjacent to the first light receiving element 19A on which the first fourth-order light L4A transmitted through the first polarizer 18A is incident has a second polarizer. The second fourth-order light L4B transmitted through 18A is incident. That is, the polarization direction of the incident fourth-order light L4 is different between the adjacent first and second light-receiving elements 19A and 19B of the light-receiving unit 19.

  Since the deflecting unit 18 and the light receiving unit 19 are configured in this manner, it is possible to collectively project and receive light in a plurality of regions of the scanning region R0 while suppressing crosstalk of light between the light receiving elements 19A. .

  Specifically, it is assumed that various objects OB are present in the scanning region R0. When the region of the scanning region R0 onto which the tertiary light L3 is projected at one time is divided into a plurality of partial regions corresponding to each of the light receiving elements 19A, the plurality of partial regions are separated by various distances. It is assumed that a target object OB (or target surface) exists.

  That is, the fourth order light L4 is incident on each of the light receiving elements 19A at various timings. The characteristics of the fourth-order light when entering the first and second light-receiving elements 19A and 19B differ depending on the surface characteristics of the projected object OB and the environment of the scanning region R0.

  Therefore, for example, even when the arrangements of the light receiving optical system 17 and the light receiving element 19 are strictly adjusted, as shown in FIG. 5, for example, one first light receiving element 19A that should be incident on one first light receiving element 19A. It is assumed that a part of the next light L4A is incident on the adjacent second light receiving element 19B.

  On the other hand, in the present embodiment, at the time of projecting light, the emitting unit 11 first regards light having different polarization directions between the first and second emitting regions 11A and 11B adjacent to each other as the secondary light L2. Emit. Then, at the time of receiving light, the light receiving unit 19 receives the fourth-order light L4 transmitted through the polarization unit 18 configured to transmit only the light corresponding to the polarization direction of the secondary light L2.

  Therefore, for example, tentatively, a part of the second fourth-order light L4B that should be incident on the first polarizer 19A of the polarization unit 19 in the second polarization direction PD2, that is, the adjacent second polarizer 19B. Is incident, the component of the second fourth-order light L4B does not pass through the first polarizer 19A. Therefore, the second quaternary light L4B that should be received by the second light receiving element 19B is suppressed from entering the first light receiving element 19A1. In this way, crosstalk of light between the first and second light receiving elements 19A19B is suppressed. Therefore, it is possible to accurately project and receive light, and it is possible to perform accurate distance measurement.

  In addition, in this embodiment, the first and second polarizers 19A and 19B are arranged alternately. Therefore, the arrangement between the light receiving optical system 17 and the polarization unit 18 and the light receiving unit 19 is within a range in which one first light receiving element 19A does not enter the two first light receiving elements 19A adjacent thereto. The composition can be adjusted.

  For example, giving priority to the incidence of the first fourth-order light L4A over the entire width direction (second direction D2) of the light-receiving surface 19S, the polarization unit 18 and the light-receiving unit 19 are configured to receive the fourth-order light L4. It can be arranged at a position different from the condensing position by. Even in this case, only the fourth-order light L4 of one polarization component transmitted through the polarizer 18A or 18B is incident on the light receiving element 19A. Therefore, while suppressing crosstalk of light between the first and second light receiving elements 19A and 19B, it is possible to perform a highly sensitive light receiving operation on the entire light receiving surface 19S, for example.

  In this embodiment, the case where the light source 12 emits the primary light L1 having a linear cross-sectional shape has been described. However, the configuration of the light source 12 is not limited to this. For example, the light source 12 may be configured to emit the dot-shaped light as the primary light L1. In this case, for example, the optical plate 14, the polarization unit 18, and the light receiving unit 19 may have a configuration according to the cross-sectional shape of the primary light L1.

  In addition, in the present embodiment, the case where the emitting portion 11 has the image forming optical system 13 and the optical plate 14 is arranged at a position where the image L1P of the light emitting surface 12S of the light source 12 is formed is described. However, the position of the optical plate 14 is not limited to this.

  For example, the emission unit 11 does not have to have the imaging optical system 12. Further, the optical plate 14 may be arranged in the immediate vicinity of the light emitting surface 12S of the light source 12. That is, the primary light L1 may be configured to pass through the optical plate 14 immediately after being emitted from the light source 12.

  In consideration of surely adjusting the polarization direction of the primary light L1, the imaging optical system 12 is arranged, and then the optical plate 14 is arranged at the image forming position of the image L1P of the light emitting surface 12S of the light source 12. Preferably. Specifically, when the light shielding portion 13 is arranged at a position other than the image formation position of the image L1P, the polarization direction of the primary light L1 that has passed through the optical plate 14 may not be adjusted reliably.

  In other words, the emitting unit 11 is provided on the optical path of the light source 11 that emits the light including the linearly polarized laser light as the primary light L1 and the optical path of the laser light, and the first region that transmits the laser light, for example. 14A and the second region 14B in which the half-wave plate is formed, and the optical plate 14 in which the second regions 14B are alternately arranged.

  Further, in the present embodiment, the case has been described in which the emitting unit 11 generates the secondary light L2 emitted from the emitting unit 11 by the light source 12 and the optical plate 14. However, the configuration of the emitting unit 11 is not limited to this. The emitting section 11 may have a plurality of emitting areas 11A and 11B that emit light, and the emitting areas 11A and 11B that are adjacent to each other may have different polarization directions of the emitted light.

  For example, in the present embodiment, the case where the first region 14A of the optical plate 14 is a region that transmits the primary light L1 and the second region 14B is a region in which the ½ wavelength plate is formed will be described. did. However, the configuration of the optical plate 14 is not limited to this.

  FIG. 6 is a diagram schematically showing the configuration of the emission unit 11M of the distance measuring device 10M according to the modified example of the present embodiment. In the distance measuring device 10M, the emission unit 11M has an optical plate 14M in which wave plates having different optical axes are arranged alternately.

  Specifically, in the present modification, the emission unit 11M includes a light source 12 that emits light including linearly polarized laser light as the primary light L1, a first half-wave plate (first wave plate). ) Is formed on the first region 14C and the second region 14C is formed with a second half-wave plate (second wave plate) having a different optic axis direction. The optical plate 14M in which the regions 14D are arranged alternately with each other.

  In the emission section 11M, the transmission areas of the primary light L1 corresponding to the first and second areas 14C and 14D of the optical plate 14M function as the first and second emission areas 11C and 11D of the emission section 11A, respectively. . Even in the case where the optical plate 14M is configured in this way, the lights having different polarization directions from the first and second emission regions 11C and 11D of the emission unit 11A are different from each other in the first and second secondary lights L2A and L2B. Is emitted as.

  Further, for example, as shown in FIG. 6, the polarization directions of the first and second secondary lights L2A and L2B may not be along the first and second directions D1 and D2, respectively. Like the emitting unit 11M, the emitting unit 11 may emit light along the polarization direction PD3 different from the first direction D1 as the second secondary light L2A, or the second secondary light L2A, for example. As the next light L2B, light along a polarization direction PD4 different from the second direction D2 may be emitted.

  Even in this case, the polarization unit 18 transmits, for example, the first and second tertiary lights L3A and L3B corresponding to the polarization directions PD3 and PD4 of the first and second secondary lights L2A and L2B. As described above, it suffices to have the first and second polarizers 18A and 18B in which the polarization directions of the lights to be transmitted are different from each other. In addition, for example, the light receiving unit 19 receives and detects the first and second fourth-order lights L4A and L4B that have passed through the first and second polarizers 18A and 18B, respectively. It suffices to have the light receiving elements 19A and 19B.

  As described above, in the present embodiment, the distance measuring device 10 has the plurality of emission areas 11A and 11B for emitting the light (secondary light L2), and emits between the emission areas 11A and 11B adjacent to each other. The emission section 11 having different polarization directions of light, the deflection section 16 for projecting the light emitted from the emission section 11 toward the object OB while deflecting the light variably, and the light reflected by the object OB (reflection). A plurality of polarizers 18A and 18B provided on the optical path of (light), and the polarization direction of the light transmitted between the adjacent polarizers 18A and 18B is different, A light receiving unit 19 having a plurality of light receiving elements 19A and 19B respectively receiving the light transmitted through each of the polarizers 18A and 18B, and a distance to the object OB is measured based on the light receiving result of the light receiving unit 19. Has a distance measuring unit 23 which, a. Therefore, the crosstalk of light between the light receiving elements 19A and 19B is suppressed, and the distance measuring device capable of performing accurate distance measurement with respect to the object OB by accurately projecting and receiving light in the scanning region R0. 10 can be provided.

  In the present embodiment, the case where the distance measuring device 10 has the deflecting unit 16 has been described. However, the distance measuring device 10 may not have the deflecting unit 16. That is, the distance measuring device 10 may be configured to emit the secondary light L2 in a predetermined direction and receive the secondary light L2 reflected by the object OB. Even in this case, crosstalk of light between the light receiving elements 19A and 19B can be suppressed, and accurate distance measurement can be performed. That is, the distance measuring device 10 may be configured to emit and receive the secondary light L2 by the emitting unit 11, the polarizing unit 18, and the light receiving unit 19.

  Further, the reception result of the fourth-order light L4 by the light receiving unit 19 can be effectively used for purposes other than distance measurement, for example, for detecting the object OB. Therefore, the distance measuring device 10 may not include the distance measuring unit 23. In this case, for example, the emitting unit 11, the polarization unit 18, and the light receiving unit 19 in the distance measuring device 10 function as a light emitting and receiving device.

  As described above, in the present embodiment, the distance measuring device 10 has the plurality of emission areas 11A and 11B for emitting light (secondary light L2), and the light emitted between the emission areas 11A and 11B adjacent to each other. And a plurality of polarizers 18A and 18B provided on the optical path of the light (reflected light L4) in which the light emitted from the emission unit 11 is reflected by the object OB, And a plurality of light-receiving units that respectively receive the light transmitted through each of the plurality of polarizers 18A and 18B of the polarization unit 18 and the polarization unit 18 in which the polarization directions of the light transmitted between the adjacent polarizers 18A and 18B are different from each other. And a light receiving section 19 having an element 19A. Therefore, it is possible to provide a light projecting / receiving device capable of suppressing light crosstalk between the light receiving elements 19A and 19B and performing accurate light projecting / receiving.

  FIG. 7 is a perspective view of the polarizing plate 32 of the emitting unit 31 in the distance measuring device 30 according to the second embodiment. FIG. 7 shows the primary light L1 immediately before entering the polarizing plate 32 and the secondary light L2 immediately after exiting from the polarizing plate 32. The distance measuring device 30 has the same configuration as the distance measuring device 10 except for the configuration of the emitting unit 31. The emitting unit 31 has the same configuration as that of the emitting unit 11 except that the light source 11 emits various kinds of light as the primary light L1 and that the optical plate 14 includes a polarizing plate 32. .

  In the present embodiment, the emission unit 31 has a plurality of polarizers (first and second polarizers 32A and 32B) provided on the optical path of the primary light L1, and these polarizers are arranged. It has a polarizing plate 32 having a polarizing region 32S.

  Further, in the polarizing plate 32, the polarization directions of the light transmitted through the first and second polarizers 32A and 32B adjacent to each other are different. In the present embodiment, the first polarizer 32A is configured to transmit the light along the first polarization direction PD1, and the second polarizer 32B transmits the light along the second polarization direction PD2. Is configured to let.

  In this embodiment, the surface of the polarization region 32S of the polarizing plate 32 from which the secondary light L2 is extracted serves as the emission surface 31S of the secondary light L2 in the emission unit 31. Further, the polarization region 32S corresponds to the regions of the polarizing plate 32 where the first and second polarizers 32A and 32B are provided, and a plurality of first and second secondary lights L2A and L2B are emitted. First and second emission areas 31A and 31B are provided.

  In other words, in the present embodiment, the emitting section 31 uses the light source 12 and the polarizing plate 32 to emit the secondary light L2 having different light polarization directions between the emitting areas 31A and 31B adjacent to each other.

  In this embodiment, by generating the secondary light L2 via the polarizing plate 32, it is possible to reliably adjust the polarization component of the secondary light L2. That is, it is possible to generate only linearly polarized light substantially along the first polarization direction PD1 as the first secondary light L2A. Further, as the second secondary light L2B, it is possible to generate only linearly polarized light substantially along the second polarization direction PD2. Therefore, it is possible to suppress a decrease in the light amount of the fourth-order light L4 when receiving light. Therefore, the light receiving accuracy of the fourth order light L4 by the light receiving unit 19 is improved.

  Further, when the secondary light L2 is generated using the polarizing plate 32 as in the present embodiment, the light source 12 does not have to have a configuration for emitting linearly polarized laser light as the primary light L1. That is, the light source 12 may generate light to be incident on the polarizing plate 32.

  Further, also in the present embodiment, considering that the secondary light L2 whose polarization component is reliably adjusted is obtained, the emitting unit 31 forms the image L1P of the light emitting surface 12S of the light source 12 into the image forming optical system. 13 is included, and the polarizing plate 32 is preferably arranged at a position where the image L1P is formed.

  As described above, in the present embodiment, the emitting unit 31 includes the light source 12 that emits light (primary light L1) and the plurality of polarizers 32A and 32B provided on the optical path of the light, and The polarizing plate 32 in which the polarization directions of the light transmitted between the polarizers 32A and 32B adjacent to each other are different. Therefore, crosstalk of light between the light receiving elements 19A is suppressed, and it is possible to provide a light emitting and receiving device capable of performing accurate light emitting and receiving, and a distance measuring device capable of performing accurate distance measuring. 30 can be provided.

10, 30 Distance measuring device 11, 31 Emitting unit 14 Optical plate 32 Polarizing plate 18 Polarizing unit 19 Light receiving unit

Claims (7)

An emission part having a plurality of emission regions for emitting light, and an emission part in which the polarization directions of the light emitted between the emission regions adjacent to each other are different,
The light emitted from the emission unit has a plurality of polarizers provided on the optical path of the reflected light reflected by the object, and the polarization directions of the light transmitted between the adjacent polarizers are different. A polarization part,
A light-receiving unit having a plurality of light-receiving elements that respectively receive the respective lights that have passed through the respective polarizers of the polarizing unit. The emitting portion is
A light source that emits laser light including linearly polarized light,
An optical plate provided on the optical path of the laser light, in which first regions for transmitting the laser light and second regions in which half-wave plates are formed are arranged alternately. The light emitting and receiving device according to claim 1. The emitting portion is
A light source that emits laser light including linearly polarized light,
A first area provided on the optical path of the laser light, in which a first half-wave plate is formed, and a second area 1/2 in which the first half-wave plate has a different optical axis direction. The light projecting / receiving device according to claim 1, further comprising: an optical plate in which a second region in which the two-wave plate is formed is arranged so as to be different from each other. The emitting section has an image forming optical system for forming an image of a light emitting surface of the light source,
The light emitting and receiving device according to claim 2, wherein the optical plate is arranged at a position where the image is formed. The emitting portion is
A light source that emits light,
The polarizing plate having a plurality of polarizers provided on the optical path of the light, and having different polarization directions of light transmitted between the polarizers adjacent to each other. Emitter / Receiver. The emitting section has an image forming optical system for forming an image of a light emitting surface of the light source,
The light emitting and receiving device according to claim 5, wherein the polarizing plate is arranged at a position where the image is formed. A light emitting and receiving device according to any one of claims 1 to 6,
A distance measuring unit that measures a distance to the target object based on a reception result of the reflected light by the light receiving unit.