JP2015184026A - laser radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration capable of ensuring the suppression of the entry of internal reflection light (noise light), if being generated on the inner surface of a transmission plate, into a light receiving portion and suppressing the occurrence of a dead angle in a near distance range near a laser radar device.SOLUTION: A first surface 71a for defining a first visual field range AR and a second surface 72a for defining a second visual field range BR are constituted in a second reflection portion 41 of a laser radar device 1. A synchronization portion 40 (guide portion) rotates a first reflection portion 21 and the second reflection portion 41 while synchronizing the first reflection portion 21 with the second reflection portion 41 so that the first visual field range AR overlaps a projection route of projected laser light L1a and that the projection route of the projected laser light L1a overlaps the second visual field range BR at a position closer than a region in which the projection route of the projected laser light L1a overlaps the first visual range AR to a case 3 in an outside portion of the case 3.

Description

  The present invention relates to a laser radar device.

  Currently, as a technique for detecting an object using laser light, for example, an apparatus as disclosed in Patent Document 1 is provided. In the apparatus of Patent Document 1, an optical isolator is provided on the optical axis of the laser light from the laser light generating means, and the optical isolator transmits the laser light from the laser light generating means and reflects it from the detection object. Light is reflected on the light receiving sensor side. Further, on the optical axis of the laser beam that has passed through the optical isolator, a concave mirror that can rotate 360 ° about the central axis in the optical axis direction is provided, and this concave mirror reflects the laser beam toward the space. At the same time, 360 ° horizontal scanning is possible by reflecting the reflected light from the object toward the light receiving sensor. Then, by calculating the rotational position of the concave mirror when the object is irradiated with the laser beam and calculating the time until the laser beam is received by the calculation unit (object position calculation unit) provided in the apparatus, The direction and distance of the object are calculated.

Japanese Patent Laid-Open No. 10-20035 JP 2011-69671 A

  By the way, in this type of laser radar apparatus, there are many cases in which a cover for the purpose of dust proofing, drip proofing, etc. is provided on the irradiation path of the laser light emitted from the deflecting unit to the external space. A light-transmitting cover (transmission plate) is disposed on the irradiation path of the light projecting laser so that the light projecting laser irradiated toward the space can pass therethrough. However, when a cover is provided on the irradiation path of the projection laser in this way, a part of the projection laser that attempts to pass through the cover from the deflecting unit is reflected by the inner surface of the cover, and the reflected light (that is, There is a possibility that noise light (which should not be detected originally) may be detected by the light receiving sensor. In particular, the reflected light generated on the inner surface of the cover is light that is reflected at a short distance without being attenuated so much by the projection laser generated by the laser light source. Is received by the light receiving sensor, the light receiving sensor is likely to reach a saturation state (that is, a light receiving state exceeding the amount of light received that generates the maximum light receiving signal).

  In particular, in a laser radar device, it is necessary to set the light receiving sensitivity of the light receiving sensor to be high to some extent so that diffuse reflected light can be detected when an object existing in an external space is irradiated with a projection laser. When noise light having a remarkably large amount of light as compared with the diffusely reflected light is received, the light receiving sensor is more likely to be saturated. If a saturation state occurs in the light receiving sensor in this way, a large amount of light is received from the light receiving sensor until a certain amount of time has passed even after the noise light causing the saturation does not enter the light receiving sensor. The signal continues to be output and the saturation state continues. In other words, if a saturated state occurs due to high-energy noise light, it takes time until the saturated state is canceled even if the noise light stops entering, and the light receiving sensor does not function normally during that time. For this reason, there is a possibility that normal detection light (regular reflected light from an object existing in the external space) that comes after the noise light cannot be accurately detected.

  For this reason, in the laser radar device, even if a part of the projection laser is reflected by the cover (light transmissive cover), the internal reflection light (noise light) generated by the reflection is not easily received by the light receiving sensor. Configuration is desired.

  On the other hand, as a configuration in which internally reflected light (noise light) generated on the inner surface of the cover is not easily received by the light receiving sensor, there is a technique as shown in FIG. In this technique, the first mirror 44 for light projection and the second mirror 45 for light reception are arranged apart from each other in the vertical direction, and the optical system on the light projecting side and the optical system on the light receiving side are divided vertically. It has become. With this configuration, even if a part of the light projecting laser emitted from the first light projecting mirror 44 is reflected by the inner surface of the light transmitting window 53 located on the scanning path, the internally reflected light (noise) Light) does not easily enter the light receiving path on the second mirror 45 side, and the above-described problem caused by noise light is less likely to occur. However, in the configuration in which the rotating mirror for light projection (first mirror 44) and the rotating mirror for light reception (second mirror 45) are separately provided and arranged apart from each other in the vertical direction, a short distance close to the apparatus. There is another problem that blind spots occur in the range.

  For example, FIG. 5 illustrates a similar configuration in which the light projecting rotating mirror 121 and the light receiving rotating mirror 141 rotate synchronously about the axis C1, and light entering the rotating mirror 141 is received by the light receiving sensor. The boundary of the visual field range Lb that can receive light at 160 is indicated by two-dot chain lines Lba and Lbb. In this example, the direction of the axis C1 is the vertical direction, the projection laser La is irradiated so as to spread in the range of the angle θa around the light projection axis La1, and spread in the range of the angle θb around the light reception axis Lb1. Thus, the visual field range Lb is determined. As in this example, in the configuration in which the light projecting rotary mirror 121 and the light receiving rotary mirror 141 are provided separately, the light projecting surface (reflecting surface) of the light projecting side rotating mirror 121 and the light receiving side rotation are provided. Since the light receiving area (reflective area) of the mirror 141 is shifted up and down, the light projecting path of the light projecting laser La is inevitably different from the visual field range Lb in the short distance range (shown as range c in FIG. 5) close to the apparatus. It will not overlap. That is, the short distance range to the position where the light projecting path of the light projecting laser La irradiated from the rotating mirror 121 and the visual field range Lb that can be received by the light receiving sensor 160 becomes a blind spot, and this short distance range. Then, even if the light projection laser La is irradiated onto the object, the reflected light is not received by the light receiving sensor.

  The present invention has been made in order to solve the above-described problems, and in a laser radar apparatus in which a light-transmitting cover (transmission plate) is disposed on a laser light projecting path, an inner surface of the cover is provided inside. Even if reflected light (noise light) is generated, it is possible to reliably prevent the light from entering the light receiving unit, and to provide a configuration that can easily reduce the non-detection area generated in the short-range range near the device. Objective.

The present invention includes a laser light generator that generates laser light;
A first reflecting unit that reflects the laser beam generated by the laser beam generating unit and irradiates the laser beam as a projection laser; and a driving unit that rotates the first reflecting unit about a predetermined vertical axis. A scanning unit that changes the direction of the light projecting laser emitted from the first reflecting unit by rotating the first reflecting unit by the driving unit;
It is configured to accommodate at least the first reflecting portion, and the light projecting laser can pass through the scanning path of the light projecting laser from the first reflecting portion at least in a circumferential direction around the first reflecting portion. A case that is blocked by a transparent plate,
A light receiving portion for receiving light;
A reflection surface is provided that is shifted in the vertical direction from the position of the first reflection part and receives reflected light, which is generated by reflection of the light projecting laser from the first reflection part by an object outside the case, as detection light. And a second reflecting portion that is inclined with respect to the vertical direction and is rotatable about the vertical rotation axis, wherein the reflective surface of the second reflective portion is the first reflective portion. The first reflecting portion and the second reflecting portion are rotated while being synchronized so as to face the irradiation side of the light projecting laser from, and the detection light entering the second reflecting portion is reflected by the reflecting surface. A guiding portion configured to guide the light receiving portion,
With
The reflection surface of the second reflection unit defines a predetermined first field of view that is received by the light receiving unit outside the case, and guides light entering from the first field of view to the light receiving unit. A second surface that defines a predetermined second visual field range that is received by the light receiving unit outside the case, and guides light that has entered from the second visual field range to the light receiving unit,
The guide unit is configured so that the first visual field range overlaps the light projecting path of the light projecting laser and the light projecting path of the light projecting laser overlaps the first visual field range outside the case. The first reflecting part and the second reflecting part are rotated while being synchronized so that the light projecting path of the light projecting laser and the second field of view overlap at a position close to the case.

According to the first aspect of the present invention, the light projecting reflecting portion (first reflecting portion) and the light receiving reflecting portion (second reflecting portion) are provided at different positions, respectively, and the light projecting reflecting portion (first reflecting portion) is provided. The light receiving reflection portion (second reflection portion) is arranged so as to be shifted up and down with respect to the light projecting path from (2). For this reason, even if a part of the light projecting laser emitted from the light reflecting part (first reflective part) is reflected by the inner surface of the transmissive plate when passing through the transmissive plate, the internally reflected light (noise light) ) Is less likely to enter the light receiving reflection part (second reflection part) or the light receiving part. Therefore, it is possible to suppress internal reflection light (noise light) generated by the transmission plate from entering the light receiving sensor, and a defect caused by such noise light being detected by the light receiving unit (for example, due to occurrence of a saturated state). The above problem) can be effectively suppressed.
However, in this configuration, since the light reflecting part (first reflective part) is arranged at a position shifted vertically from the light receiving reflective part (second reflective part), the light reflecting part (first reflective part) is arranged. Among the light projecting paths of the light projecting laser irradiated to the outside from the (1 reflecting part), a short distance range close to the light reflecting part (first reflecting part) is out of the visual field range, and this short distance range is It becomes a blind spot where an object cannot be detected.
Therefore, in this configuration, the second reflecting portion is provided with a first surface that defines the first visual field range and a second surface that defines the second visual field range. Then, the guiding unit projects the projection laser at a position closer to the case than the region where the projection path of the projection laser overlaps the first viewing field range so that the first field of view overlaps the projection path of the projection laser. The first reflecting portion and the second reflecting portion are rotated while being synchronized so that the light projecting path and the second visual field range overlap.
In this configuration, when the light projection laser is irradiated on the object within the first visual field range in the light projection path of the light projection laser, the reflected light generated in the first visual field range is guided by the first surface. With respect to a relatively far range that can be detected by the light receiving unit, reflected light is detected by guidance by the first surface. In addition, a short-distance range that cannot be completely covered by the first visual field range among the light projection paths of the light projection laser is not completely excluded from the detection target area, but at least a part is defined as the second visual field range. If the object is irradiated with the projection laser within the second visual field range, the reflected light can be guided by the second surface and detected by the light receiving unit.
In other words, in the conventional configuration in which only one field of view is defined, a range closer to the region where the field of view overlaps the light projecting path inevitably becomes a non-detection range. Since at least part of the range (non-detection range), the light projection path and the second visual field range overlap each other, even if the non-detection range cannot be detected by the first visual field range, the light projection path and the second visual field range. If the distance range overlaps the visual field range, an object can be detected. Therefore, it becomes easier to reduce the non-detection area generated in the short distance range near the apparatus.

The invention according to claim 2 condenses light from the first visual field range so that the position on the axis of the rotation axis is the focal position regardless of the rotation angle of the second reflecting portion. The second surface is configured to collect light from the second visual field range so that the position on the axis of the rotation axis is the focal position.
In this configuration, regardless of the rotation angle of the projection laser, any light in the first visual field range and the second visual field range can be condensed on the same axis. For this reason, as long as the projection laser is irradiated outside the case and the first visual field range and the second visual field range are secured outside the case, all the rotational angles can be obtained from both visual field ranges outside the case. Are easily received by a common light receiving path, and an angle range in which one of the visual field ranges cannot be detected is less likely to be generated.

In the invention of claim 3, the surface area of the first surface is larger than the surface area of the second surface.
Since the first visual field range set on the first surface is a range in which an object in a farther area is detected, the reflected light generated at a longer distance can be reduced as much as possible by relatively increasing the surface area of the first surface. The light can be easily received. On the other hand, since the second field of view set on the second surface is a range for detecting an object in a closer area, the surface area of the second surface is relatively small so that it is reflected by a short-range object. Therefore, it is possible to prevent excessive reflected light having a large energy from being excessively received, and to easily suppress saturation in the light receiving unit due to excessively large reflected light.

FIG. 1 is a cross-sectional view schematically illustrating a laser radar device according to a first embodiment of the invention. FIG. 2 is an explanatory diagram showing a relationship between a light projection path and a light receiving field in the laser radar apparatus of FIG. FIG. 3 is an explanatory diagram for explaining the relationship between the first reflecting portion, the second reflecting portion, the transmission plate, and the like on the cut surface cut at the position AA in FIG. FIG. 4 is a perspective view schematically showing the vicinity of a second reflecting portion used in the laser radar apparatus of FIG. FIG. 5 is an explanatory diagram for explaining the problems of the comparative example in which the light projecting optical system and the light receiving optical system are separated. 6A is a graph illustrating a received light waveform in the case where the surface area of the first surface is smaller than the surface area of the second surface in the laser radar device shown in FIG. 1, and FIG. 2 is a graph illustrating a light receiving waveform when the surface area of the first surface is larger than the surface area of the second surface in the laser radar device shown in FIG.

[First embodiment]
Hereinafter, a first embodiment of a laser measuring device according to the present invention will be described with reference to the drawings.
(Basic configuration of laser radar device)
First, the outline of the laser radar device 1 will be described with reference to FIG.
FIG. 1 is a cross-sectional view schematically illustrating the overall configuration of the laser radar device 1 according to the first embodiment. FIG. 1 schematically shows a configuration in which the laser radar device 1 is cut along a predetermined cut surface (a cut surface passing through the central axis C and parallel to the vertical direction and the front-rear direction).

  As shown in FIG. 1, the laser radar device 1 includes a laser diode 10 and a photodiode 60 that receives reflected light from a detection object, and determines the distance and direction to the detection object existing in a scanning area outside the device. It is configured as a detection device.

  The laser diode 10 corresponds to an example of a “laser light generation unit” that generates laser light. For example, the laser diode 10 is configured by an infrared laser diode or the like, and is driven by a control circuit 70 (not shown). ), And a pulse laser beam corresponding to the pulse current is intermittently emitted every predetermined short time. In FIG. 1 and the like, a path from the laser light emitted from the laser diode 10 to the first reflecting portion 21 is indicated by a symbol L1, and the light reflected by the first reflecting portion 21 is projected by the light projecting laser. L1a.

  The photodiode 60 is composed of, for example, an avalanche photodiode. For example, the photodiode 60 includes a light receiving region that receives light so as to face the upper side, and detects light incident on the light receiving region. The photodiode 60 generates laser light from the laser diode 10, and when the laser light is irradiated to the outside of the case 3 and reflected by a detection object (not shown) existing outside the apparatus, the reflected light (not shown) Specifically, it functions to receive and convert the reflected light into the first visual field range AR or the second visual field range and guided to the light receiving region into an electrical signal.

  In the present embodiment, the photodiode 60 corresponds to an example of a “light receiving unit” that receives light, and laser light L1 irradiated by a scanning unit described later is reflected from an object existing in the external space. It functions to detect reflected light.

  A light guide lens 12 is provided on the path of the laser light emitted from the laser diode 10. The light guide type lens 12 allows the laser light emitted from the irradiation surface 10a of the laser diode 10 to enter from an incident surface 81 formed on one end side in the predetermined direction of the laser diode 10, and the laser light that has entered enters the predetermined direction of the laser diode 10 in the predetermined direction. It is configured to emit from the exit surface 82 on the other end side, and is disposed on the axis of a central axis C described later, and functions as a lens that collects light incident from the entrance surface 81.

  The light guide lens 12 is formed in a longitudinal shape extending in the axial direction of the central axis C, and a cross section perpendicular to the longitudinal direction (Y-axis direction) of the light guide lens 12 becomes larger toward the lower side. The structure gradually spreads. An end surface (upper end surface) at one end portion in the longitudinal direction of the light guide lens 12 is configured as a flat surface orthogonal to the longitudinal direction (Y-axis direction), and the upper end surface functions as the incident surface 81. The incident surface 81 is disposed to face (for example, contact with) the outer surface of the laser diode 10 on the light emission side. Further, the end surface (lower end surface) of the other end portion in the longitudinal direction is configured as a curved surface that expands slightly downward, and this lower end surface functions as the exit surface 82. Moreover, between the entrance surface 81 and the exit surface 82, side wall portions are disposed on both sides in the front-rear direction and both sides in the left-right direction, and are configured, for example, in a substantially quadrangular pyramid shape as a whole.

  In this light guide type lens 12, the internal reflection by the laser light to be transmitted inside the lens is repeated, and the laser light L1 is emitted from the emission surface 82 in a state of being shaped into a predetermined shape. ing. Specifically, the laser beam L1 emitted from the emission surface 82 spreads at a predetermined angle θ11 in the plane direction parallel to the front-rear direction and the vertical direction, and predetermined in the plane direction parallel to the horizontal direction and the vertical direction. The laser beam L1 is condensed so as to spread at an angle θ12. These angles θ11 and θ12 may be 0 ° or may be acute angles determined in advance. In this configuration, for example, the angles θ11 and θ12 are substantially the same as the angle θ1 shown in FIG.

  In the example of FIG. 1 and the like, the light guide type lens 12 as shown in FIG. 1 and the like is used as a lens member. However, any lens that can condense the laser light generated by the laser diode 10 into parallel light or the like. For example, other collimating lenses may be used.

  A scanning device 20 is provided on the path of the laser light L1 from the light guide lens 12. The scanning device 20 corresponds to an example of a “scanning unit”, and includes a first reflecting unit 21 that reflects the laser light L1 generated by the laser diode 10 and guided by the light guide type lens 12 as the light projecting laser L1a, and a predetermined amount. And a motor 30 that rotates the first reflecting portion 21 around the central axis C in the vertical direction. And this scanning apparatus 20 rotates the 1st reflection part 21 with the motor 30, and the direction of the laser beam (projection laser L1a) irradiated from the 1st reflection part 21 is a plane orthogonal to the central axis C The direction (horizontal direction) is changed.

  In the scanning device 20, the rotating body includes a first reflecting portion 21 configured to be rotatable and a shaft portion 23 connected to the first reflecting portion 21, and rotatably supports the shaft portion 23. The rotating mechanism is configured by providing a bearing (which is fixedly held at a predetermined position inside the case 3 and not shown in FIG. 1). The first reflector 21 functions to reflect the laser light from the laser diode 10 (specifically, the laser light L1 guided by the light guide lens 12) toward the space outside the case 3. ing.

  The first reflecting portion 21 includes a flat reflecting surface 21a disposed on the path of the laser light L1 emitted from the light guide type lens 12, and is disposed so as to be rotatable about a central axis C extending in the vertical direction. It is installed. The axial direction of the central axis C serving as the rotation center of the first reflecting portion 21 is substantially coincident with the direction of the optical axis of the laser light L1 incident on the first reflecting portion 21 from the light guide type lens 12, and this laser light. An incident position where L1 enters the first reflecting portion 21 (more specifically, a position where the optical axis of the laser beam L1 and the reflecting surface 21a overlap) is a position P1 on the axis of the central axis C on the reflecting surface 21a. Has been.

  Further, in this configuration, the position P1 and its peripheral portion on the reflecting surface 21a of the first reflecting portion 21 are flat surfaces inclined at an angle of, for example, 45 ° with respect to the vertical direction. In the present specification, a direction parallel to the axis of the central axis C is defined as a vertical direction, and a plane direction orthogonal to the vertical direction is defined as a horizontal direction. Accordingly, the optical axis direction of the laser beam L1 before entering the reflecting surface 21a of the first reflecting section 21 is the vertical direction, and the optical axis L1a ′ of the light projecting laser L1a after being reflected by the reflecting surface 21a (FIG. 2). The direction of is the horizontal direction. As shown in FIG. 2, the light projecting laser L1a after being reflected by the reflecting surface 21a is irradiated so as to spread at a predetermined angle θ1 with the optical axis L1a ′ in the horizontal direction as the center.

  In the present specification, the vertical direction is also referred to as the vertical direction or the vertical direction, and in FIG. 1, the vertical direction is indicated as the Y-axis direction. Further, a predetermined direction orthogonal to the vertical direction (Y-axis direction) is defined as the front-rear direction, and in FIGS. 1 and 3, this front-rear direction is illustrated as the X-axis direction. In addition, the direction perpendicular to the vertical direction and the front-rear direction is the left-right direction, and in FIG. 3, this left-right direction is shown as the Z-axis direction.

  In the present configuration, the first reflecting portion 21 rotates around the central axis C in the direction that coincides with the direction of the optical axis of the laser light L1 that is about to enter the first reflecting portion 21, and thus the first reflecting portion 21. Regardless of the rotation position (rotation angle), the incident angle of the laser beam L1 on the reflecting surface 21a is always maintained at 45 °, and the optical axis L1a ′ of the projection laser L1a irradiated from the position P1 on the reflecting surface 21a. It operates so that the orientation of FIG. 2 is constantly maintained in the horizontal direction (direction perpendicular to the central axis C).

  The motor 30 that rotates the first reflecting portion 21 corresponds to an example of a “driving portion”, and the shaft portion 23 is rotated to rotationally drive the first reflecting portion 21 connected to the shaft portion 23. As a specific configuration of the motor 30, various known motors such as a DC motor, an AC motor, and a step motor can be used.

Next, the synchronization unit 40 will be described.
In this configuration, the synchronization unit 40 is configured by the shaft portion 23, a bearing (not shown) that rotatably supports the shaft portion 23, the motor 30 that rotationally drives the shaft portion 23, and the second reflection portion 41. ing. The synchronization unit 40 corresponds to an example of a “guidance unit”, and the first reflection unit 21 and the first reflection unit 21 are arranged so that the reflection surface of the second reflection unit 41 faces the irradiation side of the projection laser L1a from the first reflection unit 21. The detection light (light generated by the projection laser L1a being reflected by an external object) entering the second reflection unit 41 is reflected by the reflection surface 41a and rotated by synchronizing with the second reflection unit 41, and the photodiode 60 (light reception unit). ).

  The second reflecting portion 41 is arranged so as to be shifted in the vertical direction from the position of the first reflecting portion 21 described above, and the reflection generated by the projection laser L1a irradiated from the first reflecting portion 21 being reflected by an object outside the case. A reflection surface 41a that receives light as detection light is provided. The reflecting surface 41a is inclined with respect to the vertical direction and is rotatable about a vertical rotation axis (center axis C).

  As shown in FIGS. 1 and 4, the second reflecting portion 41 functions as a concave mirror in which most of the area of the reflecting surface 41a is configured as a predetermined paraboloid (first surface 71a). A partial region of 41a is configured as a paraboloid (second surface 72a) having a different inclination from the first surface 71a. Thus, the surface area of the first surface 71a is larger than the surface area of the second surface 72a.

  As shown in FIGS. 1 and 2, the first surface 71 a is a region that defines a predetermined first visual field range AR that is received by the photodiode 60 outside the case 3, and a portion provided with the first surface 71 a. However, it functions as the first concave mirror 71 that collects and reflects the light entering from the first visual field range AR and guides it to the photodiode 60. Further, the second surface 72a is a region that defines a predetermined second visual field range BR that is received by the photodiode 60 outside the case 3, and a portion where the second surface 72a is provided extends from the second visual field range BR. It functions as a second concave mirror 72 that reflects the incident light while collecting it and guiding it to the photodiode 60.

  As shown in FIG. 2, the first surface 71a is configured with a predetermined curvature state and a predetermined inclination state, and has a predetermined direction (the direction of the first visual field range AR around the light receiving optical axis AR1) and a predetermined region (the first area). The reflected light of one field-of-view range AR is reflected while being reflected toward one side (downward) in the axial direction of the central axis C, and the focal position of the collected reflected light is For example, the shape is adjusted so as to be on the axis of the central axis C and on the light receiving surface of the photodiode 60.

  The second surface 72a is configured, for example, in a curvature state different from the first surface 71a and in an inclined state different from the first surface 71a, in a predetermined direction (the direction of the second visual field range BR around the light receiving optical axis BR1), and Reflected light that is collected while being reflected while reflecting the reflected light of a predetermined region (the region between the boundary BRa and the boundary BRb of the second visual field range BR) toward one side (downward) in the axial direction of the central axis C For example, the shape is adjusted so that the focal position is on the axis of the central axis C and on the light receiving surface of the photodiode 60.

  Then, as shown in FIG. 2, the first visual field range AR overlaps the light projection path of the light projection laser L1a outside the case 3, and the light projection path of the light projection laser L1a and the first visual field range AR overlap. The shapes of the first surface 71a and the second surface 72a so that the light projecting path of the light projecting laser L1a and the second visual field range BR overlap each other at a position closer to the case 3 than the area (a position within the range c shown in FIG. 2). Has been adjusted.

  In this configuration, the shaft portion 23 serving as a drive shaft of the motor 30 extends in the vertical direction and extends to the lower side of the motor 30. And the 2nd reflection part 41 is being fixed to the lower end part of this axial part 23, the 1st reflective part 21, the axial part 23, and the 2nd reflective part 41 are rotatably supported by the bearing which is not shown in figure. It is designed to rotate integrally. With this configuration, the reflection surface 41a of the second reflection unit 41 faces the irradiation side of the projection laser L1a from the first reflection unit 21 (that is, the projection light of the projection laser L1a from the reflection surface 21a). The first reflecting portion 21 and the second reflecting portion 41 are rotated in synchronization with each other so that the light receiving optical axes AR1 and BR1 from the first surface 71a and the second surface 72a are directed to the side toward the axis L1a ′. become.

  In the present configuration, the first surface 71a is positioned on the axis of the central axis C (rotation axis) (specifically, the photodiode 60) regardless of the rotation angle of the second reflection unit 41 in the entire rotation range. The position on the light receiving surface) is focused on the light from the first field-of-view range AR, and the second surface 72a is rotated at any rotation angle. However, the light from the second visual field range BR is condensed so that the position on the axis of the central axis C (rotation axis) (specifically, the position on the light receiving surface of the photodiode 60) is the focal position. It has a configuration.

  Further, regardless of the rotation angle of the second reflecting portion 41, the light projecting laser L1a and the first field of view in a virtual plane (projecting plane) passing through the optical axis L1a ′ and the central axis C of the light projecting laser L1a. The relationship between the range AR and the second visual field range BR is as shown in FIG. That is, regardless of the rotation angle of the second reflection unit 41, the first reflection unit 21 and the second reflection unit 21 are arranged such that the light reception optical axis AR1 and the light reception optical axis BR1 are positioned on the virtual plane (light projection plane). The light projecting optical axis with respect to the horizontal direction perpendicular to the vertical direction on the virtual plane (light projecting plane), regardless of the rotation angle of the second reflecting unit 41 while rotating in synchronization with the reflecting unit 41. The angle of L1a ′, the angle of the light receiving optical axis AR1, and the angle of the light receiving optical axis BR1 are kept constant. Whatever the rotation angle of the second reflecting portion 41, the upper and lower boundaries ARb and ARa of the first visual field range AR with respect to the horizontal direction orthogonal to the vertical direction on the virtual plane (projection plane). The angle and the angles of the upper and lower boundaries BRb and BRa of the second visual field range BR are kept constant.

  Since the rotation angle of the first reflecting portion 21 and the second reflecting portion 41 is configured as described above, “the projection laser L1a is irradiated to the outside of the case 3, and the first visual field range AR and the second visual field range are set. When the BR is within the “rotational angle range set outside the case 3” (that is, within the rotational angle range in which the opening of the window portion 4e exists on the side where the first reflecting portion 21 and the second reflecting portion 41 face). In the case 3, the first visual field range AR overlaps the light projecting path of the light projecting laser L1a outside the case 3, and the case 3 is more than the region where the light projecting path of the light projecting laser L1a and the first visual field range AR overlap. The first reflecting portion 21 and the second reflecting portion 41 are rotated in synchronization so that the light projecting path of the light projecting laser L1a and the second visual field range BR overlap each other at a position close to.

  In this configuration, as shown in FIG. 1, a rotation angle for detecting a rotation angle position of the shaft portion 23 driven by the motor 30 (that is, a rotation angle position of the first reflection portion 21 and the second reflection portion 41). A sensor 32 is provided. As the rotation angle sensor 32, various known sensors can be used as long as they can detect the rotation angle position of the shaft portion 23, such as a rotary encoder. The rotation angle sensor 32 detects, for example, how much the shaft portion 23 has rotated from a predetermined reference angle (the rotation angle of the shaft portion 23 when the optical axis L1a ′ of the light projecting laser L1a is directed to the predetermined reference direction). And functions to specify the direction of the projection plane in the horizontal direction (that is, the direction of the optical axis L1a ′ of the projection laser L1a in the horizontal direction).

  Further, in the laser radar device 1 of this configuration, as shown in FIGS. 1 and 3, the laser diode 10, the light guide type lens 12, the scanning device 20, the photodiode 60, the second reflecting portion 41, and the like are inside the case 3. And is protected against dust and shocks. FIG. 3 conceptually shows the cross-sectional structure at the position AA in FIG. 1, and schematically shows the frame that holds the motor 30 and the bearing that holds the shaft portion 23. .

  As shown in FIGS. 1 and 3, the case 3 includes a main case portion 4 and a transmission plate 5, and is configured in a box shape as a whole. As shown in FIG. 1, the main case portion 4 is configured such that the upper wall portion 4 a and the lower wall portion 4 b are vertically opposed to each other, and the peripheral wall portion 4 c is configured as an outer peripheral wall as shown in FIGS. 1 and 3. . The peripheral wall portion 4c is arranged so as to surround various components arranged between the upper wall portion 4a and the lower wall portion 4b in the circumferential direction around the central axis C, and the peripheral wall configured in this way A part of the part 4c is opened as a window part 4e so that light can be guided. The window portion 4e is a portion that is opened so as to allow light to enter and exit from the main case portion 4, and has a predetermined circumferential direction around the first reflecting portion 21 and the second reflecting portion 41 (direction Fa shown in FIG. 3). To the direction Fb), and a predetermined vertical region (a constant height range) is opened through the entire circumferential predetermined region. And the permeation | transmission board 5 which consists of a transparent resin plate, a glass plate, etc. is arrange | positioned so that the window part 4e of this open form may be obstruct | occluded. In this way, in a part in the circumferential direction around the first reflecting portion 21 and the second reflecting portion 41, a transmission plate through which the light projecting laser L1a can pass through the scanning path of the light projecting laser L1a from the first reflecting portion 21. It becomes the structure obstructed by. 1 and 3 conceptually show the state when the optical axis L1a ′ of the light projecting laser L1a faces the front direction (X-axis positive direction). At this rotation angle, the first reflecting portion 21 is shown. The projection laser L1a irradiated from the laser beam enters the transmission plate 5 at the position P2, passes through the transmission plate 5, and is irradiated to the outside.

  In the example shown in FIGS. 1, 3, etc., the transmission plate 5 is disposed so as to surround a part in the circumferential direction around the first reflection unit 21 and the second reflection unit 41. The window part 4e may be comprised over the circumferential direction whole range around the 2nd reflection part 41, and the permeation | transmission board 5 may be arrange | positioned so that the circumferential direction whole range may be surrounded.

(Detection process)
In the laser radar device 1 configured as described above, the light projection laser L1a is projected by the scanning device 20 (scanning unit) with respect to a horizontal direction orthogonal to the vertical direction (in the examples of FIGS. 1 and 2, etc.). , And scanning at an angle of 0 °). Further, due to the operation of the synchronization unit 40 (guidance unit), in a predetermined rotation angle range in which the projection laser L1a passes through the region of the transmission plate 5 between the position Fa and the position Fb, as shown in FIG. The first viewing field AR overlaps with the projecting path of the projecting laser L1a, and the projecting laser L1a projects at a position closer to the case 3 than the region where the projecting path of the projecting laser L1a and the first viewing field AR overlap. The first reflecting portion 21 and the second reflecting portion 41 rotate while being synchronized so that the optical path and the second visual field range BR overlap.

  When the object detection operation is performed in the laser radar device 1, the rotation angles θ of the first reflection unit 21 and the second reflection unit 41 (respective rotation angles from a predetermined reference rotation position (for example, a position where the rotary encoder indicates the origin)). Is determined, the irradiation direction of the projection laser L1a from the apparatus is specified. If the laser radar device 1 is installed in a desired inclination state (for example, a state in which the scanning direction of the light projecting laser L1a is always perpendicular to the vertical direction), the photodiode 60 is separated from the object. By detecting the rotation angle of the first reflection unit 21 and the second reflection unit 41 when the reflected light is received by the rotation angle sensor 32, the orientation of the object can be accurately detected. Note that whether or not the photodiode 60 has received the reflected light from the object can be determined, for example, based on whether or not the amount of light received by the photodiode 60 (that is, the output from the photodiode 60) exceeds a threshold value. "When the reflected light exceeding the threshold is received by the photodiode 60" is "When the reflected light from the object is received".

  Also, the time from when laser light (pulse laser light) is generated by the laser diode 10 until the reflected light corresponding to the laser light (reflected light generated when the projection laser L1a hits the object) is detected by the photodiode 60. If T is detected, the length La of the optical path from the generation of the laser light to the reception of the reflected light can be calculated based on the time T and the speed of light c, for example, by an equation such as La = T × c. If the distance Lb from the laser diode 10 to the predetermined reference position (for example, the position P1) is known, the distance L from the predetermined reference position (for example, the position P1) of the laser radar device 1 to the detection object can be accurately obtained. it can. That is, it is possible to accurately detect the distance and the direction from the laser radar device 1 to the detection object.

  In this configuration, after the laser light is generated by the laser diode 10, the laser light (projection laser L 1 a) is irradiated on the object in the first visual field range AR, and the reflected light is received by the photodiode 60. In this case, the elapsed time from the light projection timing to the light reception timing in the laser diode 10 is equal to or longer than a predetermined threshold time. On the other hand, when the laser light is generated by the laser diode 10 and then the object is irradiated with the laser light (projection laser L1a) in the second visual field range BR and the reflected light is received by the photodiode 60, the laser diode The elapsed time from the light projection timing at 10 to the light reception timing is less than the above threshold time. Therefore, when a laser beam is generated in the laser diode 10 and a reflected light from the laser beam is detected by the photodiode 60, the elapsed time from the light projection timing to the light reception timing in the laser diode 10 is equal to or more than the above threshold time. If so, it can be determined that the object is detected in the first visual field range AR, and if it is less than the threshold time, it can be determined that the object is detected in the second visual field range BR. In this way, the light reception waveform from the first visual field range AR and the light reception waveform from the second visual field range BR can be handled separately, so that processing suitable for each light reception waveform can be handled separately. It becomes.

(Main effects of this configuration)
In this configuration, the light reflecting part (first reflective part 21) and the light receiving reflective part (second reflective part 41) are provided at different positions, respectively, and the light reflecting part (first reflective part 21) is provided. The light receiving reflection part (second reflection part 41) is arranged so as to be shifted up and down with respect to the light projecting path from (2). For this reason, even if a part of the laser light emitted from the light reflecting portion (the first reflecting portion 21) is reflected by the inner surface of the transmitting plate 5 when passing through the transmitting plate 5, the internally reflected light is reflected. (Noise light) is less likely to enter the light receiving reflection part (second reflection part 41) and the light receiving part (photodiode 60). Therefore, it is possible to suppress internal reflection light (noise light) generated by the transmission plate from entering the light receiving sensor, and a defect caused by such noise light being detected by the light receiving unit (for example, due to occurrence of a saturated state). The above problem) can be effectively suppressed. In particular, a space for accommodating the light projecting optical system (the first reflecting portion 21 and the like) and a light receiving optical system (the second reflecting portion) at a predetermined position in the vertical direction (for example, the position of the two-dot chain line W shown in FIG. 1). 41, the photodiode 60, etc.) are provided with a light-shielding wall that partitions the space for accommodating the space, the noise light suppression effect is further enhanced.

However, in this configuration, since the reflecting portion for light projection (first reflecting portion 21) is arranged at a position shifted vertically from the reflecting portion for receiving light (second reflecting portion 41), no measures should be taken. Among the light projecting paths of the light projecting laser L1a irradiated to the outside from the light projecting reflecting section (first reflecting section 21), there is a short distance range close to the projecting reflecting section (first reflecting section 21). The short-range range becomes a blind spot where an object cannot be detected. Therefore, in the present configuration, the second reflecting portion 41 is provided with a first surface 71a that defines the first visual field range AR and a second surface 72a that defines the second visual field range BR. The synchronization unit 40 (guidance unit) is configured so that the first visual field range AR overlaps the light projection path of the light projection laser L1a and the light projection path of the light projection laser L1a overlaps the first visual field range AR. Also, the first reflecting portion 21 and the second reflecting portion 41 are rotated while being synchronized so that the light projecting path of the light projecting laser L1a and the second visual field range BR overlap at a position close to the case 3.
In this configuration, when the object is irradiated with the light projection laser L1a in the first visual field range AR in the light projection path of the light projection laser L1a, the reflected light generated in the first visual field range AR is the first. The light can be guided by the surface 71a and detected by the photodiode 60 (light receiving portion), and the reflected light is detected by guidance by the first surface 71a in a relatively far range. In addition, a short-distance range that cannot be completely covered by the first visual field range AR among the light projection paths of the light projection laser L1a is not completely excluded from the detection target area, but at least a part of the second visual field range BR. When the object is irradiated with the projection laser L1a within the second visual field range BR, the reflected light can be guided by the second surface 72a and detected by the photodiode 60 (light receiving unit). it can.
In other words, in the conventional configuration in which only one field of view is defined, a range closer to the region where the field of view overlaps the light projecting path inevitably becomes a non-detection range. Since at least part of the range (non-detection range), the light projection path and the second visual field range BR overlap each other, even if the non-detection range cannot be detected by the first visual field range AR, If the distance range overlaps with the second visual field range BR, the object can be detected. Therefore, it becomes easier to reduce the non-detection area generated in the short distance range near the apparatus.

Further, in this configuration, regardless of the rotation angle of the second reflecting portion 41, the first field of view range is such that the first surface 71a has the focal position at the position on the axis of the central axis C (rotation axis). The light from the AR is collected, and the second surface 72a is configured to collect the light from the second visual field range BR so that the position on the axis of the central axis C (rotation axis) is the focal position. Yes.
In this configuration, regardless of the rotation angle of the projection laser L1a, any light in the first visual field range AR and the second visual field range BR can be condensed on the same axis. For this reason, as long as the projection laser L1a is irradiated outside the case 3 and the first visual field range AR and the second visual field range BR are secured outside the case 3, the rotation angle L1a Light from both visual field ranges outside the case is easily received by a common light receiving path, and an angle range that makes it impossible to detect one visual field range is less likely to occur.

  In this configuration, the surface area of the first surface 71a is larger than the surface area of the second surface 72a. Since the first visual field range AR set on the first surface 71a is a range in which an object in a farther area is detected, the reflection that has occurred farther away by relatively increasing the surface area of the first surface 71a. Light can be received as easily as possible. On the other hand, since the second visual field range BR set on the second surface 72a is a range in which an object in a closer area is detected, the surface area of the second surface 72a is relatively small, so It is possible to prevent excessive reflected light having a large energy when reflected from being excessively received, and to easily suppress saturation in the light receiving unit caused by reflected light that is too large.

  6A shows that when the surface area of the second surface 72a is equal to or larger than the surface area of the first surface 71a, a part of the light projecting laser L1a hits the object in the second visual field range BR. An example of a received light waveform when the remaining projection laser L1a that has passed behind the object hits another object at a position close to the first visual field range AR (position close to the case 3) is shown. FIG. 6B shows that when the surface area of the second surface 72a is less than the surface area of the first surface 71a, a part of the projection laser L1a is an object in the second field of view range BR. In this case, an example of the received light waveform when the remaining light projecting laser L1a that has passed behind the object hits another object at a position close to the first visual field range AR (a position close to the case 3) is shown. 6A and 6B, the horizontal axis represents the elapsed time from the time T0, and the vertical axis represents the level of the received light signal (for example, the voltage generated from the photodiode 60 in response to light reception). Signal level). The time T0 is a point in time when a drive pulse for irradiating the laser diode 10 with laser light is applied, V1 is a threshold level for determining that an object has been detected, and V2 is from the photodiode 60. This is the maximum level (saturation level) of the received light signal.

  As shown in FIG. 6A, when the size of the surface area of the second surface 72a is greater than or equal to the size of the surface area of the first surface 71a, a large second visual field range BR for detecting a short distance is secured. Since the amount of light received from the second visual field range BR by the photodiode 60 increases, the level of the received light signal when the light from the second visual field range BR is received easily reaches the saturation level V2 ( (See waveform W11 in FIG. 6A). When a light receiving state that reaches the saturation level occurs in this way, the amount of charge in the photodiode 60 becomes too large, and the light received by the photodiode 60 disappears as shown in the light receiving waveform W11 in FIG. Even after this, the light reception signal continues to be maintained without being lowered. That is, immediately after reaching the threshold level V1 at time T11, even if the level of received light is reduced to a low level (a level that is essentially determined to be less than the threshold level), the light reception output from the photodiode 60 is received. Since the signal continues to be maintained at the threshold level or higher, as shown in FIG. 6A, the light from the first visual field range AR is received before the level of the received light signal (waveform W11) returns below the threshold level V1. Then, the light receiving waveform W11 of the light (light in the second visual field range BR) received first and reaching the threshold level at time T11, and the light in the first visual field range AR (originally received) The light reception signal does not fall below the threshold between the light reception waveform W12 and the light reception waveform W12 of the light from the first visual field range AR. That is, the light reception waveform T11 and the light reception waveform T12 form one mountain and are determined as one object, and thus the light reception waveform W12 of the light from the first visual field range AR cannot be recognized, and the detection of the object is omitted. Will occur.

  On the other hand, when the size of the surface area of the second surface 72a is less than the size of the surface area of the first surface 71a as in the configuration shown in FIG. 1, FIG. 2, FIG. The second visual field range BR is suppressed to be narrow, and the amount of light received from the second visual field range BR by the photodiode 60 is suppressed. Therefore, the light reception signal when the light from the second visual field range BR is received Becomes difficult to reach the saturation level V2 (see waveform W21 in FIG. 6B). In this way, the light that does not reach the saturation level rapidly decreases when the light reception is lost as compared with the case where the saturation level is reached as shown by the waveform W11 in FIG. Therefore, after that, the reflected light (the reflected light when the light projection laser L1a is irradiated to the object at a short distance of the first visual field range AR) such that the received light waveform W22 is equivalent to the received light waveform W12 of FIG. ) Is received, at time T22 when the received light waveform W22 reaches the threshold level V1, it is highly possible that the received light waveform W21 is below the threshold level V1. Therefore, the light reception waveform W21 and the light reception waveform W22 can be clearly distinguished and detected from two objects (an object in the second visual field range BR and an object in the first visual field range AR) according to the light projection laser L1a. When each reflected light returns, each object can be detected more reliably.

[Other Embodiments]
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  In the above-described embodiment, the concave mirror is exemplified as the second reflecting portion 41. However, a known structure using a known deflecting unit (for example, a deflecting unit configured as an inclined plane mirror) that is not a concave mirror structure may be employed. For example, one or both of the first surface 71a and the second surface 72a may be configured as a plane mirror. When both the first surface 71a and the second surface 72a are configured by a plane mirror, the angle formed by the first surface 71a and the horizontal direction is different from the angle formed by the second surface 72a and the horizontal direction. It only has to be done.

  In the above embodiment, the second surface 72a is provided near the central portion of the reflective surface 41a and the first surface 71a is provided around the second surface 72a, but the position of the second surface 72a is not limited to the vicinity of the central portion, It may be near the end of the reflecting surface 41a.

  In the above embodiment, the laser diode 10 such as an infrared laser diode is exemplified as the laser light generating unit, but other known laser diodes and other light sources may be used.

  In the above embodiment, the photodiode 60 such as an avalanche photodiode is exemplified as the light receiving unit, but other known light receiving sensors (other types of photodiodes or other light receiving sensors) may be used.

  In the above-described embodiment, the configuration in which the light collected by the second reflecting unit 41 configured as a concave mirror is directly received by the light receiving unit without using a lens is exemplified. However, the second reflecting unit 41 configured as a concave mirror is illustrated. A configuration may be adopted in which the light collected by the lens is collected by a lens and received by a light receiving unit (photodiode 60). In other words, both the light reflected while being collected by the first surface 71a and the light reflected while being collected by the second surface 72a are both collected by the lens and received by the light receiving unit (photodiode 60). May be. Further, the light reflected while being collected on the first surface 71a and the light reflected while being collected on the second surface 72a are received by the light receiving unit (photodiode 60) via another optical component such as a mirror. It may be a configuration.

  In the said embodiment, although the axial part which supports the 1st reflection part 21 and the axial part which supports the 2nd reflection part 31 were shown as an example, these may be comprised as a different body. In this case, instead of the configuration of the motor 30 of FIG. 1, for example, a rotational driving force from the motor is provided with a shaft portion that supports the first reflecting portion 21 by a transmission mechanism such as a gear or a pulley, and the second reflecting portion 41. Each of the shaft portions may be rotated in synchronization with the shaft portions to be supported. Moreover, the structure which rotates the axial part which supports the 1st reflection part 21, and the axial part which supports the 2nd reflection part 41 by synchronizing with a respectively separate motor may be sufficient.

DESCRIPTION OF SYMBOLS 1 ... Laser radar apparatus 3 ... Case 5 ... Transmission board 10 ... Laser diode (laser beam generation part)
20 ... Scanning device (scanning section)
21 ... 1st reflection part 30 ... Motor (drive part)
40 ... Synchronizing part (guidance part)
41 ... 2nd reflecting part 41a ... Reflecting surface 60 ... Photodiode (light receiving part)
71a ... 1st surface 71b ... 2nd surface C ... Center axis (rotation axis)
AR: First visual field range BR: Second visual field range L1: Laser light L1a: Projection laser

Claims (3)

A laser light generator for generating laser light;
A first reflecting unit that reflects the laser beam generated by the laser beam generating unit and irradiates the laser beam as a projection laser; and a driving unit that rotates the first reflecting unit about a predetermined vertical axis. A scanning unit that changes the direction of the light projecting laser emitted from the first reflecting unit by rotating the first reflecting unit by the driving unit;
It is configured to accommodate at least the first reflecting portion, and the light projecting laser can pass through the scanning path of the light projecting laser from the first reflecting portion at least in a circumferential direction around the first reflecting portion. A case that is blocked by a transparent plate,
A light receiving portion for receiving light;
A reflection surface is provided that is shifted in the vertical direction from the position of the first reflection part and receives reflected light, which is generated by reflection of the light projecting laser from the first reflection part by an object outside the case, as detection light. And a second reflecting portion that is inclined with respect to the vertical direction and is rotatable about the vertical rotation axis, wherein the reflective surface of the second reflective portion is the first reflective portion. The first reflecting portion and the second reflecting portion are rotated while being synchronized so as to face the irradiation side of the light projecting laser from, and the detection light entering the second reflecting portion is reflected by the reflecting surface. A guiding portion configured to guide the light receiving portion,
With
The reflection surface of the second reflection unit defines a predetermined first field of view that is received by the light receiving unit outside the case, and guides light entering from the first field of view to the light receiving unit. A second surface that defines a predetermined second visual field range that is received by the light receiving unit outside the case, and guides light that has entered from the second visual field range to the light receiving unit,
The guide unit is configured so that the first visual field range overlaps the light projecting path of the light projecting laser and the light projecting path of the light projecting laser overlaps the first visual field range outside the case. A laser radar, wherein the first reflecting portion and the second reflecting portion are rotated while being synchronized so that a light projecting path of the light projecting laser and the second visual field range overlap at a position close to the case. apparatus. The first surface is configured to collect light from the first visual field range so that a position on the axis of the rotation axis is a focal position regardless of the rotation angle of the second reflection unit. Yes,
The second surface is configured to condense light from the second visual field range so that the position on the axis of the rotation axis is a focal position regardless of the rotation angle of the second reflection unit. The laser radar apparatus according to claim 1, wherein the laser radar apparatus is provided.   3. The laser radar device according to claim 1, wherein a surface area of the first surface is larger than a surface area of the second surface. 4.

Images