JP2010060479A - Object detecting device and method for detecting optical axis misalignment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an object detecting device capable of improving the workability related to the optical axis alignment by detecting any misalignment between an optical axis of a light projecting section for projecting the light forward and an optical axis of a light receiving section for receiving the reflected light projected by the light projecting section. <P>SOLUTION: A light projecting section 3 has a light projecting-side light guide 32 to form an optical waveguide for guiding the light outgoing from an LD 31 to a light projection lens 33 between the LD 31 and the light projection lens 33. The light projecting-side light guide 32 takes the form having a protruding surface where a light outgoing surface in opposition to the light projection lens 33 is in the planar surface form protruding to the outside of an outer circumferential portion. Further, a light receiving section 4 has a light receiving-side light guide 42 to form an optical waveguide for guiding the light received via a light receiving lens 43 to a PD 41 between the PD 41 and the light receiving lens 43. The light receiving-side light guide 42 has the same planar surface form of a light incoming surface in opposition to the light receiving lens 43 as that of the light outgoing surface of the light projecting-side light guide 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an object detection apparatus that scans light projected forward and detects an object existing in front, and an optical axis deviation detection method that detects an optical axis deviation in the object detection apparatus.

  Conventionally, in an apparatus using a light source, in many cases, it has been necessary to adjust the optical axis of light emitted from the light source. For example, in a projection-type image display device, as shown in Patent Document 1, optical axis adjustment of R, G, and B is performed by projecting a pattern such as a cross shape and adjusting its projection position. Yes. In Patent Document 2, centering adjustment of a filament of a microscope light source is performed using a target screen on which a cross mark is formed. Specifically, adjustment is performed by projecting a light source of a microscope onto a target screen placed on a sample stage of the microscope.

  Patent Document 3 describes an optical coupling device that couples a first optical waveguide device and a second optical waveguide device having a spot size smaller than that of the first optical waveguide device. This optical coupling device is provided with protrusions or the like on a clad layer formed so as to surround a core layer whose shape is changed in a taper shape in the light propagation direction, and the surface shape and size of the clad layer is the same as that of the first optical waveguide device. It proposes to match the shape and size of the spot size.

Furthermore, by detecting the reflected light of the laser light projected forward, a laser radar that detects an object existing in the direction where the laser light was projected and measures the distance to the detected object has been put into practical use. Yes. For example, the laser radar is used as a device that is mounted on a vehicle and detects a preceding vehicle traveling ahead, an obstacle existing ahead, and the like. In the laser radar, as disclosed in Patent Document 4, it is necessary to match the optical axis of the light projecting unit that projects laser light and the optical axis of the light receiving unit that receives the reflected light.
JP 2004-221716 A JP-A-8-304740 Japanese Patent Laid-Open No. 9-15435 JP 2000-329853 A

  An object of the present invention is an optical axis alignment operation for aligning an optical axis of a light projecting unit that projects light forward and an optical axis of a light receiving unit that receives reflected light of light projected by the light projecting unit. It is an object of the present invention to provide an object detection device and an optical axis deviation detection method capable of improving the performance.

  In order to achieve the above object, the object detection apparatus of the present invention is configured as follows.

  The light projecting unit has a light emitting element such as a laser diode (LD), and projects the light emitted from the light emitting element forward through the light projecting lens. The light receiving unit has a light receiving element such as a photodiode (PD), and the light projecting unit receives the reflected light of the light projected forward, that is, the reflected light from the object, through the light receiving lens. To do. The scanning unit maintains the relative positional relationship between the light projecting lens and the light receiving lens and moves these lenses to scan the light projected forward by the light projecting unit and scan the light. Reflected light from the direction is received by the light receiving unit. Therefore, it is possible to detect an object located in the scanning range in which the scanning unit scans the light depending on whether or not the reflected light is received by the light receiving element of the light receiving unit.

  The light projecting unit has a light projecting side light guide that forms an optical waveguide that guides light emitted from the light emitting element to the light projecting lens between the light emitting element and the light projecting lens. The light projecting unit projects forward light having a shape corresponding to the emission surface of the light projecting side light guide. The light-projecting side light guide has a shape in which the planar shape of the exit surface facing the light projecting lens has a projecting surface projecting outside the outer peripheral portion. Therefore, the light emitted forward from the light projecting portion includes light emitted from the projecting surface.

  Furthermore, the light receiving unit includes a light receiving side light guide that forms an optical waveguide that guides light received through the light receiving lens to the light receiving element between the light receiving lens and the light receiving element. In the light receiving side light guide, the planar shape of the incident surface facing the light receiving lens is the same as the planar shape of the emitting surface of the light projecting side light guide. Therefore, if the optical axis of the light projecting unit and the optical axis of the light receiving unit match, the light emitted from the projecting surface of the light emitting side light guide is projected from the incident surface of the light receiving side light guide. Incident on the surface. In other words, the light axis of the light projecting unit and the light of the light receiving unit are set so that the light emitted from the projecting surface of the light emitting side light guide is incident on the projecting surface of the light receiving side light guide. By adjusting the axis, the optical axis of the light projecting unit and the optical axis of the light receiving unit can be matched.

  The detection of whether or not the optical axis of the light projecting unit is shifted from the optical axis of the light receiving unit may be performed as follows.

  First, a reflector having a smaller outer shape than the portion of the light corresponding to the protruding surface of the light-projecting light guide projected at this position is installed at the position where the light projected from the light projecting unit is projected. . What is necessary is just to determine suitably the position which installs this reflecting plate.

  Next, the change in the amount of light received by the light receiving element of the light receiving unit relative to the scanning direction when the scanning unit scans the reflecting plate in the first direction with the light corresponding to the projecting surface of the light projecting side light guide by the scanning unit. A first measurement process to be measured is performed. Further, the light projecting direction of the light in the second direction orthogonal to the first direction is changed by the scanning unit, and the reflection plate is scanned in the first direction with the light that is not the protruding surface of the light projecting side light guide. A second measurement process is performed to measure a change in the amount of light received by the light receiving element of the light receiving unit with respect to the scanning direction. In the measurement results of the first measurement process and the second measurement process, whether the reflected light according to the shape of the light projected from the light projecting part at the installation position of the reflector is received by the light receiving part. Thus, it is possible to detect whether or not the optical axes of the light projecting unit and the light receiving unit are shifted. Specifically, in the second measurement process, the length in the first direction in which the reflected light can be received by the light receiving unit is appropriate for the length in the first direction of the light scanned on the reflector. The deviation of the optical axis in the first direction can be detected depending on whether or not there is.

  Furthermore, if the length in the first direction in which the reflected light can be received by the light receiving unit is not appropriate, the amount of deviation of the optical axis in the first direction can be obtained from the difference from the appropriate length. In addition, the position where the reflected light can be received by the light receiving unit with respect to the scanning position in the first direction in the first measurement process, and the light reflected by the light receiving unit with respect to the scanning position in the first direction in the second measurement process. The shift direction of the optical axis in the first direction can be obtained by the position where the light can be received and the shape of the light projected from the light projecting portion at the installation position of the reflector. Further, by performing the second measurement process a plurality of times with different light projection directions in the second direction, the optical axis deviation amount and the optical axis deviation direction in the second direction can be obtained. Accordingly, when the optical axis is shifted, the light that matches the optical axis of the light projecting unit that projects light forward and the optical axis of the light receiving unit that receives the reflected light of the light projected by this light projecting unit Axis alignment workability can be improved.

  According to the present invention, the optical axis alignment operation is performed to match the optical axis of the light projecting unit that projects light forward and the optical axis of the light receiving unit that receives the reflected light of the light projected by the light projecting unit. Can be improved.

  Embodiments of the present invention will be described below.

  FIG. 1 is a block diagram showing a configuration of a main part of a laser radar according to an embodiment of the present invention. The laser radar 1 includes a control unit 2, a light projecting unit 3, a light receiving unit 4, a scanning unit 5, and an input / output unit 6. The laser radar 1 is mounted on a vehicle and detects an object (a preceding vehicle, a pedestrian, or the like) positioned in front of the vehicle. Hereinafter, a vehicle equipped with the laser radar 1 is referred to as a host vehicle. Further, the laser radar 1 generates detected object information for each detected object including an orientation with respect to the own vehicle, a distance from the own vehicle, a relative speed with respect to the own vehicle, whether it is a stationary object or a moving object, and the like. . The laser radar 1 notifies the detected object information of each generated object to a vehicle-side control device (not shown). Based on the notification from the laser radar 1, the vehicle-side control device performs traveling control related to braking of the host vehicle.

  The controller 2 controls the operation of each part of the main body of the laser radar 1 to detect an object located in front of the host vehicle and generate detected object information relating to the detected object. The light projecting unit 3 projects laser light in front of the host vehicle in accordance with an instruction from the control unit 2. The light receiving unit 4 detects the reflected light of the laser light projected by the light projecting unit 3. The scanning unit 5 scans the laser light projected by the light projecting unit 3 in front of the host vehicle in the horizontal direction and the vertical direction. The input / output unit 6 controls input / output with the vehicle-side control device.

  The light projecting unit 3 includes a drive control circuit 30, a laser diode 31 (hereinafter referred to as “LD 31”), a light projecting side light guide 32, and a light projecting lens 33. The drive control circuit 30 controls the light emission of the LD 31 that is a light emitting element based on the light emission instruction from the control unit 2. The light emitting surface of the LD 31 faces the incident surface of the light projecting side light guide 32. Further, the emission surface of the light projecting side light guide 32 faces the light projecting lens 33. The light projecting side light guide 32 forms an optical waveguide that guides the laser light emitted from the LD 31 to the light projecting lens 33. In the light projecting side light guide 32, the laser light incident from the LD 31 is repeatedly refracted inside and propagates to the exit surface. The light projection side light guide 32 has the center of the incident surface aligned with the optical axis of the laser beam emitted from the LD 31. The light projecting lens 33 is attached to be movable in the horizontal direction (vehicle width direction of the host vehicle) and the vertical direction (height direction of the host vehicle) with respect to the emission surface of the light projecting side light guide 32. The light projection lens 33 is moved by the scanning unit 5 as will be described later.

  The light receiving unit 4 includes an A / D converter 40, a photodiode 41 (hereinafter referred to as PD 41), a light receiving side light guide 42, and a light receiving lens 43. The light projecting lens 33 and the light receiving lens 43 are lenses having the same focal length. In addition, the light projecting lens 33 and the light receiving lens 43 are mechanically connected, and are mounted so as to be movable while maintaining a relative positional relationship. However, the relative positional relationship between the light projecting lens 33 and the light receiving lens 43 can be adjusted with an adjusting screw or the like. The light projecting lens 33 and the light receiving lens 43 are arranged in the vehicle width direction of the host vehicle. The light receiving side light guide 42 is disposed between the light receiving lens 43 and the PD 41. The light receiving side light guide 42 has an incident surface facing the light receiving lens 43 and an emitting surface facing the light receiving surface of the PD 41. The light receiving side light guide 42 forms an optical waveguide that guides the light incident through the light receiving lens 43 to the PD 41. The light receiving side light guide 42 has the center of the incident surface aligned with the center of the light receiving surface of the PD 41. Therefore, the PD 41 receives the light incident on the light receiving side light guide 42 via the light receiving lens 43. The A / D converter 40 converts the output of the PD 41 into a digital value and inputs it to the control unit 2. That is, the A / D converter 40 inputs a digital value corresponding to the amount of light received by the PD 41 to the control unit 2.

  Here, the light projecting side light guide 32 and the light receiving side light guide 42 are the same member. However, the exit surface of the light projecting side light guide 32 corresponds to the entrance surface of the light receiving side light guide 42, and the entrance surface of the projecting side light guide 32 corresponds to the exit surface of the light receiving side light guide 42.

  In addition, if the light emitting side light guide 32 and the light receiving side light guide 42 have the same shape as the emission surface of the light emitting side light guide 32 and the incident surface of the light receiving side light guide 42, the optical axis The length of the direction may be different, and the shape of the incident surface of the light projecting side light guide 32 and the shape of the outgoing surface of the light receiving side light guide 42 may be different.

  The scanning unit 5 includes a horizontal direction moving unit 51, a vertical direction moving unit 52, and a scanning position detection unit 53. The horizontal direction moving unit 51 moves the connected light projecting lens 33 and the light receiving lens 43 in the horizontal direction, and the light projecting unit 3 scans the laser light projected in front of the host vehicle in the horizontal direction. . The vertical direction moving unit 52 moves the connected light projecting lens 33 and the light receiving lens 43 in the vertical direction, and the light projecting unit 3 scans the laser light projected in front of the host vehicle in the vertical direction. . The scanning position detection unit 53 detects the horizontal scanning position and the vertical scanning position of the laser light and inputs them to the control unit 2.

The scanning unit 5 maintains the relative positional relationship between the light projecting lens 33 and the light receiving lens 43, and moves these lenses 33 and 43 in the horizontal direction and the vertical direction.

  The input / output unit 6 acquires vehicle information such as the traveling speed of the host vehicle from the vehicle-side control device, and notifies the vehicle-side control device of detected object information relating to the detected object.

  Since detection of an object located in front of the host vehicle in the laser radar 1 and generation of detected object information relating to the detected object are known, they will be briefly described here. In the laser radar 1, the scanning unit 5 scans the laser light projected forward from the light projecting unit 3 in the horizontal direction and the vertical direction, and the reflected light is received by the light receiving unit 4 to detect an object. To do. Further, the direction in which the light projecting unit 3 projects the laser beam applied to the reflected light received by the light receiving unit 4 is detected as the direction in which the object exists. As described above, the scanning unit 5 maintains the relative positional relationship between the light projecting lens 33 and the light receiving lens 43 and moves the lenses 33 and 43 in the horizontal direction and the vertical direction. Reflected light from the direction can be received by the light receiving unit 4. Further, the distance to the object is detected based on the time from when the light projecting unit 3 projects the laser light forward until the light receiving unit 4 receives the reflected light. Furthermore, the moving speed and moving direction of the object are detected from the previous detection result of the object and the traveling speed and traveling direction of the host vehicle obtained from the vehicle control device. Based on these detection results, the laser radar 1 generates detected object information including an orientation with respect to the own vehicle, a distance from the own vehicle, a relative speed with the own vehicle, whether it is a stationary object or a moving object, and the like. This is notified to the vehicle-side control device.

  Next, the light emitting side light guide 32 and the light receiving side light guide 42 will be described. As described above, since the light projecting side light guide 32 and the light receiving side light guide 42 are members having the same shape, the light projecting side light guide 32 will be described as an example here. FIG. 2 is a diagram illustrating a light projecting side light guide. The light projecting side light guide 32 has a substantially rectangular parallelepiped shape, and has a shape in which a protrusion 32a is provided on the exit surface side (see FIG. 2A). The protrusion 32a is formed at the approximate center on the long side of the emission surface. The protrusion 32a is not provided continuously from the incident surface to the exit surface, but is formed from the middle of the entrance surface and the exit surface toward the exit surface. In addition, the protrusion 32a is formed in a tapered shape that increases as it approaches the exit surface, and the cross-sectional area of the protrusion 32a increases as it approaches the exit surface. As shown in FIG. 2B, the planar shape of the emission surface of the light projecting side light guide 32 is a convex shape having a protruding surface at a part of the outer peripheral portion (see FIG. 2B). This protruding surface is due to the above-described protrusion 32a. This projecting surface is located at the center of the long side of the rectangle.

  In addition, the planar shape of the incident surface of the light projection side light guide 32 is a rectangle as shown in FIG.

  Next, laser beam scanning by the scanning unit 5 will be briefly described. As described above, the scanning unit 5 can move the light projecting lens 33 and the light receiving lens 43 in both the horizontal direction and the vertical direction. A top view of the optical system of the light projecting unit 3 and the light receiving unit 4 is shown in FIG. That is, FIG. 3 shows the optical path of the laser light when the light projecting lens 33 and the light receiving lens 43 are moved in the horizontal direction. A side view of the optical system of the light projecting unit 3 and the light receiving unit 4 is shown in FIG. That is, FIG. 4 shows the optical path of the laser light when the light projecting lens 33 and the light receiving lens 43 are moved in the vertical direction.

  The laser light emitted from the LD 31 is incident on the light projecting side light guide 32 and is emitted from the exit surface of the light projecting side light guide 32. The light projection lens 33 focuses the laser light emitted from the light emission surface of the light projection side light guide 32 on the focal point. That is, the laser beam emitted from the emission surface of the light projecting side light guide 32 is polarized in the center direction of the light projecting lens 33 by the light projecting lens 33. This polarization angle is determined by the incident position of the laser light in the light projecting lens 33 and the focal length of the light projecting lens 33. For example, as shown in FIGS. 3A and 4A, when the emission surface of the light projection side light guide 32 faces the center of the light projection lens 33, the laser light is almost polarized. Instead, the light is projected in front of the light projecting lens 33. On the other hand, as shown in FIGS. 3B and 4B, when the emission surface of the light projecting side light guide 32 does not face the center of the light projecting lens 33, the laser light is emitted from the light projecting lens. The light is polarized in the direction of the center of the light projecting lens 33 and projected in front of the light projecting lens 33.

  Thus, the scanning unit 5 can scan the laser light projected forward from the light projecting unit 3 in the horizontal direction by moving the light projecting lens 33 and the light receiving lens 43 in the horizontal direction. Similarly, when the scanning unit 5 moves the light projecting lens 33 and the light receiving lens 43 in the vertical direction, the laser light projected forward from the light projecting unit 3 can be scanned in the vertical direction.

  The laser light incident on the light receiving lens 43 is polarized by the light receiving lens 43 into a light beam parallel to the optical axis of the light receiving lens 43. This polarization angle is determined by the incident angle of the laser beam with respect to the light receiving lens 43. For example, as shown in FIGS. 3A and 4A, the laser light parallel to the optical axis of the light receiving lens 43 passes through the light receiving lens 43 with almost no polarization, and receives the light guide 42 on the light receiving side. Is incident on. On the other hand, as shown in FIG. 3B and FIG. 4B, laser light that is not parallel to the optical axis of the light receiving lens 43 is polarized by the light receiving lens 43 in a direction parallel to the optical axis of the light receiving lens 43. And enters the light receiving side light guide 42. The laser light incident on the light-receiving side light guide 42 is received by the light-receiving surface of the PD 41 facing the emission surface of the light-receiving side light guide 42.

  When the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 are shifted, the laser radar 1 cannot receive the reflected light of the laser light projected forward by the light projecting unit 3 with the light receiving unit 4. The object cannot be detected properly. In other words, the laser radar 1 needs to adjust and match the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4. The laser radar 1 can detect the optical axis shift between the light projecting unit 3 and the light receiving unit 4, and adjusts the optical axis to match the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4. Such work can be easily performed.

  Hereinafter, the function of detecting the deviation between the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 will be described while explaining the procedure of the work for adjusting the optical axis in the laser radar 1.

  When light emitted from the projecting surface of the light emitting side light guide 32 is incident on the projecting surface of the light receiving side light guide 42, the light axis of the light projecting unit 3 and the light of the light receiving unit 4 are used. The axis matches. In other words, the light axis of the light projecting unit 3 and the light reception so that the light emitted from the projecting surface of the light emitting side light guide 32 is incident on the projecting surface of the light receiving side light guide 42. The optical axis of the unit 4 may be adjusted.

  The laser light projected forward from the light projecting unit 3 spreads, and has a beam shape shown in FIG. 5 at a position away from the light projecting unit 3 to some extent (several tens of meters). In FIG. 5, a portion surrounded by a broken line is a portion corresponding to the light emitted from the projecting surface on the emission surface of the light projecting side light guide 32.

  First, an operator installs the reflecting plate 100 at a position away from the light projecting unit 3 to some extent (see FIG. 6). The azimuth | direction which installs the reflecting plate 100 should just be in front of the light projection part 3 front. The size of the reflecting plate 100 is smaller than the portion corresponding to the projecting surface of the laser light projected from the light projecting unit 3 at the installation position.

  Note that an object that reflects the laser light projected from the light projecting unit 3 is not placed around the reflector 100. Further, in order to prevent the reflection of the laser light around the reflector 100, a light absorbing plate may be provided around the reflector 100.

  Next, as shown in FIG. 7A, the operator applies laser light emitted from the portion corresponding to the protruding surface of the light projecting side light guide 32 to the reflecting plate 100 at the installation position of the reflecting plate 100. Adjust to the position where it will be projected. This adjustment may be performed by moving the light projection lens 33 by the scanning unit 5, or the relative relationship between these lenses provided in the holding mechanism of the connected light projection lens 33 and the light receiving lens 43. It is also possible to use an adjustment mechanism that adjusts the positional relationship. The position at which the laser light emitted from the portion corresponding to the projecting surface of the light projecting side light guide 32 is projected onto the reflecting plate 100 is set in the laser radar 1 as the reference position of the light projecting lens 33. The reference position includes a horizontal reference position and a vertical reference position.

  Next, the operator positions the light receiving lens 43 with respect to the light projecting lens 33 in a state where the laser light emitted from the portion corresponding to the projecting surface of the light projecting side light guide 32 is projected onto the reflecting plate 100. Is adjusted to a position where the amount of reflected light received by the light receiving unit 4 is maximized. This adjustment is performed by an adjustment mechanism provided in a holding mechanism for the connected light projecting lens 33 and light receiving lens 43. By this adjustment, the reflected light reflected by the reflecting plate 100, that is, the reflected light of the laser light emitted from the portion corresponding to the protruding surface of the light projecting side light guide 32, enters the incident surface of the light receiving side light guide 42. It becomes a state.

  However, at this time, the optical axes of the light projecting unit 3 and the light receiving unit 4 are not necessarily aligned. Specifically, the reflected light of the laser light emitted from the portion corresponding to the projecting surface of the light projecting side light guide 32 is the projecting surface of the incident surface of the light receiving side light guide 42 as shown in FIG. Or incident on a portion other than the projecting surface of the incident surface of the light receiving side light guide 42 as shown in FIGS. 7C, 7D, 7E, etc. is there.

Next, the operator inputs to the laser radar 1 an instruction to execute the optical axis deviation detection process. In response to this input, the laser radar 1 sets a plurality of scanning positions including the previously set reference position for the vertical scanning position. Specifically, with respect to the vertical direction, the reference position set earlier and one or more scanning positions above the reference position are set. Here, in the vertical direction,
(A) Position (reference position) at which the laser beam emitted from the portion corresponding to the projecting surface of the light projecting side light guide 32 is irradiated on the reflecting plate 100 (see FIG. 8A).
(B) The position at which the laser beam emitted from the rectangular upper portion of the light projecting side light guide 32 is applied to the reflecting plate 100 (see FIG. 8B).
(C) The position at which the laser beam emitted from the rectangular central portion of the light projecting side light guide 32 is applied to the reflecting plate 100 (see FIG. 8C).
(D) Position at which the laser beam emitted from the lower rectangular portion of the light projecting side light guide 32 is irradiated onto the reflector 100 (see FIG. 8D).
These four scanning positions are set.

  Note that the number of scanning positions set in the vertical direction is not limited to four, but may be two or more including the reference position.

  The laser radar 1 scans the laser beam in the horizontal direction at every four scanning positions set in the vertical direction this time, and measures the change in the amount of light received by the light receiving unit 4 with respect to the horizontal scanning position. When the optical axes of the light projecting unit 3 and the light receiving unit 4 are aligned, the amount of received light shown in FIGS. 9A to 9D for each of the scanning positions in the vertical direction (a) to (d). Is measured. On the other hand, as shown in FIGS. 7C, 7D, and 7E, if the optical axes of the light projecting unit 3 and the light receiving unit 4 are deviated, the vertical directions (a) to (d) are performed. The amount of received light obtained for each scanning position in the direction is as shown in FIGS. FIG. 10 shows the amount of light received by the light receiving unit 4 with respect to the horizontal scanning position measured when the optical axis shift between the light projecting unit 3 and the light receiving unit 4 is in the state shown in FIG. Is a change. FIG. 11 shows the amount of light received by the light receiving unit 4 with respect to the horizontal scanning position measured when the optical axis shift between the light projecting unit 3 and the light receiving unit 4 is in the state shown in FIG. Is a change. FIG. 12 shows the amount of light received by the light receiving unit 4 with respect to the horizontal scanning position measured when the optical axis shift between the light projecting unit 3 and the light receiving unit 4 is in the state shown in FIG. Is a change. The laser radar 1 outputs a change in the amount of light received by the light receiving unit 4 with respect to the horizontal scanning position measured at each scanning position set in the vertical direction as an optical axis deviation detection result. The detection result of the optical axis deviation is output via the input / output unit 6. The operator can check the detection result of the optical axis deviation with a display device or the like connected to the input / output unit 6.

  As shown in FIGS. 10 to 12, when the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 are shifted in the vertical direction, the light receiving unit 4 can receive the reflected light from the reflecting plate 100. There is no vertical scanning position. Further, as the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 become larger in the vertical direction, the vertical scanning position where the reflected light from the reflecting plate 100 is not received in the light receiving unit 4. The number of Therefore, in the light receiving unit 4, the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 are in the vertical direction depending on whether or not there is a vertical scanning position where the reflected light from the reflecting plate 100 cannot be received. It can be determined whether or not there is a deviation. Further, the amount of deviation between the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 in the vertical direction can be determined from the number of vertical scanning positions where the reflected light from the reflecting plate 100 is not received.

  Further, here, the emission surface of the light projecting side light guide 32 and the incident surface of the light receiving side light guide 42 have a shape having a protruding surface at the center of the long side of the rectangle. Therefore, the peak of the change in the amount of light received by the light receiving unit 4 with respect to the horizontal scanning position measured at the vertical reference position is the peak of the light receiving unit 4 with respect to the horizontal scanning position measured at other vertical scanning positions. Whether or not there is a deviation between the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 in the horizontal direction can be determined depending on whether or not it is located at the center of the peak of the change in the amount of received light. Further, from the deviation between this peak and the center of this mountain, the direction in which the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 are displaced in the horizontal direction and the amount of deviation can be determined.

  The operator determines whether or not the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 are deviated from the detection result of the optical axis deviation output from the laser radar 1, and if the optical axis is deviated, The optical axes of the light projecting unit 3 and the light receiving unit 4 are adjusted. Then, the above-described operation is performed again.

  Thus, the operator can determine whether or not the optical axis of the light projecting unit 3 and the optical axis of the light receiving unit 4 are misaligned, and when the optical axis is misaligned, the misalignment amount can be determined. The adjustment operation for aligning the optical axis of the light and the optical axis of the light receiving unit 4 can be performed easily.

  Further, the length of the projection 32a provided on the light-projecting side light guide 32 may be any length as long as the reflected light can be obtained at the position of the reflector 100 installed when performing the optical axis adjustment described above. As shown in FIG. 3, the light may be provided continuously from the incident surface to the output surface. However, the length of the protrusion 32a is erroneously detected by detecting the reflected light by projecting the laser light projected from the projecting surface onto a roadside installation such as a signboard provided above the road. It is preferable to decide in consideration of the possibility of Specifically, as shown in FIG. 14, the length L of the protrusion 32a is irradiated at the position of the reflecting plate 100 installed when detecting the optical axis deviation (see FIG. 14B). It is preferable that the length is not irradiated at a distance of several tens of meters (see FIG. 14C).

  The exit surface of the light projecting side light guide 32 may have a protruding surface on the right or left side instead of the center on the long side of the rectangle, or the protruding surface may be provided on the short side of the rectangle. . Further, the emission surface may have another shape such as a square or an ellipse as long as it has a protruding surface.

It is a block diagram which shows the structure of the principal part of a laser radar. It is a figure which shows the light emission side light guide. It is a figure explaining the scanning of a horizontal direction. It is a figure explaining the scanning of a perpendicular direction. It is a figure which shows the beam shape of the laser beam projected ahead. It is a figure explaining an optical axis adjustment procedure. It is a figure explaining the shift | offset | difference of an optical axis. It is a figure explaining an optical axis adjustment procedure. It is a figure which shows the light reception amount when an optical axis is suitable. It is a figure which shows the light reception amount when an optical axis has shifted | deviated. It is a figure which shows the light reception amount when an optical axis has shifted | deviated. It is a figure which shows the light reception amount when an optical axis has shifted | deviated. It is a figure which shows the light projection side light guide concerning another embodiment. It is a figure which shows the light projection side light guide concerning another embodiment.

Explanation of symbols

1-Laser radar 2-Control unit 3-Light projection unit 4-Light reception unit 5-Scanning unit 30-Drive control circuit 31-Laser diode (LD)
32-light-projecting side light guide 32a-projection 33-light-projecting lens 40-A / D converter 41-photodiode (PD)
42-light-receiving side light guide 42a-projection 43-light-receiving lens 100-reflecting plate

Claims (6)

A light projecting unit that projects light emitted from the light emitting element forward through the light projecting lens;
A light receiving unit that receives reflected light of the light projected forward by the light projecting unit with a light receiving element via a light receiving lens;
In an object detection apparatus comprising: a scanning unit that holds a relative positional relationship between the light projecting lens and the light receiving lens and moves these lenses;
The light projecting unit includes a light projecting side light guide that forms an optical waveguide that guides light emitted from the light emitting element to the light projecting lens between the light emitting element and the light projecting lens.
This light-projecting-side light guide has a shape in which the planar shape of the exit surface facing the light projecting lens has a projecting surface that projects outside the outer peripheral portion,
The light receiving unit includes a light receiving side light guide that forms an optical waveguide that guides light received through the light receiving lens to the light receiving element between the light receiving lens and the light receiving element,
This light-receiving-side light guide is an object detection device in which a planar shape of an incident surface facing the light-receiving lens is the same shape as a planar shape of an emitting surface of the light-projecting-side light guide. The light-projecting side light guide has a rectangular plane shape on the exit surface and a shape having the protruding surface on the long side,
2. The light receiving side light guide according to claim 1, wherein a planar shape of an incident surface is a rectangle like the emission surface of the light projecting side light guide, and the protruding surface is on the long side. Object detection device. The light-projecting side light guide has a rectangular shape on the exit surface and a shape having the projecting surface at the center on the long side,
The light receiving side light guide has a shape in which a planar shape of an incident surface is a rectangle like the emission surface of the light projecting side light guide, and has a shape having the protruding surface in the center on the long side. The object detection apparatus described.   4. The object detection device according to claim 1, wherein the light projecting side light guide has a cross-sectional shape in a direction perpendicular to the optical axis, and the area of the projecting surface increases as the surface approaches the exit surface.   5. The object detection device according to claim 1, wherein the light-receiving side light guide has a cross-sectional shape in a direction perpendicular to the optical axis, and the area of the protruding surface increases as the surface approaches the incident surface. In the object detection device according to any one of claims 1 to 5, an optical axis deviation detection method for detecting whether or not the optical axes of the light projecting unit and the light receiving unit are deviated,
A reflector having a smaller outer shape than that of the portion corresponding to the protruding surface of the light-projecting side light guide projected at this position is installed at the position where the light projected from the light projecting unit is projected. And
The scanning unit moves the light projecting lens and the light receiving lens in the first direction, and scans the reflecting plate in the first direction with light of a portion corresponding to the projecting surface of the light projecting side light guide. And performing a first measurement process for measuring a change in the amount of light received by the light receiving element of the light receiving unit with respect to the scanning direction,
Further, the scanning unit moves the light projecting lens and the light receiving lens in a second direction orthogonal to the first direction to change a light projecting direction in the second direction, and thereby project the light projecting. A second measurement process of scanning the reflector in the first direction with the light of the light-side light guide that is not the protruding surface, and measuring a change in the amount of light received by the light-receiving element of the light-receiving unit with respect to the scanning direction; Done
An optical axis misalignment detection method for detecting whether or not the optical axes of the light projecting unit and the light receiving unit are deviated based on the measurement results obtained in the first measurement process and the second measurement process. .

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