WO2017183530A1 - Object detection device - Google Patents

Object detection device Download PDF

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Publication number
WO2017183530A1
WO2017183530A1 PCT/JP2017/014925 JP2017014925W WO2017183530A1 WO 2017183530 A1 WO2017183530 A1 WO 2017183530A1 JP 2017014925 W JP2017014925 W JP 2017014925W WO 2017183530 A1 WO2017183530 A1 WO 2017183530A1
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WO
WIPO (PCT)
Prior art keywords
light
light source
light beam
object detection
mirror surface
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PCT/JP2017/014925
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French (fr)
Japanese (ja)
Inventor
亮太 石川
将史 影山
Original Assignee
コニカミノルタ株式会社
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Priority to JP2018513127A priority Critical patent/JPWO2017183530A1/en
Publication of WO2017183530A1 publication Critical patent/WO2017183530A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes

Definitions

  • the present invention relates to an optical scanning type object detection apparatus capable of detecting a distant object.
  • an object detection device adopting the TOF (Time of Flight) method has already been developed.
  • the TOF method the distance to the object can be measured by measuring the time until the pulsed laser light hits the object and returns.
  • the object detection device adopting the TOF method is generally used to amplify an APD (avalanche photodiode) or the like in order to detect the weak reflected light generated when a laser beam is irradiated to a distant object.
  • a light receiving element with a high rate is used.
  • a plurality of light receiving elements that receive reflected light are arranged to ensure high resolution.
  • Patent Document 1 discloses a rotating mirror unit having a first mirror surface and a second mirror surface that are inclined with respect to a rotation axis, and at least one that emits a light beam toward an object through the mirror unit.
  • a light projection system including a light source, and the light beam emitted from the light source is reflected by the first mirror surface of the mirror unit and then travels toward the second mirror surface, and further the second
  • a radar which is reflected by a mirror surface and projected while being scanned with respect to the object in accordance with the rotation of the mirror unit.
  • the luminous flux emitted from the light projecting system is reflected by the rotating first mirror surface and the second mirror surface, and then is irradiated toward the object. Since the light is incident on the light receiving system after being reflected by the first mirror surface and the second mirror surface, in principle, only the reflected light of the projected light is incident on the light receiving system. It has the advantage of having a resolution and a wider field of view.
  • Patent Document 1 discloses that a plurality of light sources can be used to increase the number of scanning lines without deteriorating longitudinal distortion, it is clear that the detection range can be expanded while downsizing the apparatus. There is no disclosure.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide an object detection apparatus that can be made compact while using a plurality of light sources and can expand a detection range.
  • an object detection device reflecting one aspect of the present invention.
  • a rotating or oscillating mirror unit having a plurality of mirror surfaces inclined at different angles with respect to the rotation axis;
  • a light projecting system including a first light source and a second light source for emitting a light beam;
  • a light receiving system including a light receiving element that receives a reflected light beam from the object, and an object detection device having: At least a part of the first light beam emitted from the first light source and incident on the mirror surface and the second light beam emitted from the second light source and incident on the mirror surface are at least partially on the mirror surface.
  • the first light beam and the second light beam reflected by the mirror surface are projected while being scanned toward the object, and the reflected light beam is reflected by the mirror surface and received by the light receiving element. It is supposed to In the cross section in the direction perpendicular to the optical axis of the first light flux and the second light flux within the object detection region, the size in the direction corresponding to the scanning direction is smaller than the size in the direction corresponding to the scanning orthogonal direction It is.
  • an object detection device that can be made compact while using a plurality of light sources and can expand the detection range.
  • FIG. 1 is a schematic diagram showing a state in which a laser radar as an object detection device according to the present embodiment is mounted on a vehicle.
  • the laser radar LR of the present embodiment is provided on the inner side of the upper end of the front window 1a of the vehicle 1, but may be disposed outside the vehicle (such as behind the front grill 1b).
  • FIG. 2 is a perspective view schematically showing the main part excluding the housing of the laser radar LR according to the present embodiment.
  • the shape and length of the components may differ from the actual ones.
  • the outgoing light beam and the reflected light beam are shown only on the optical axis (light beam center).
  • the laser radar LR converts, for example, a pulsed semiconductor laser (first light source) LD1 that emits a laser beam and a divergent angle of divergent light from the semiconductor laser LD1 into weakly divergent light.
  • Collimating lens (first collimating lens) CL1 pulse-type semiconductor laser (second light source) LD2 that emits a laser beam, and narrowing the divergence angle of the divergent light from the semiconductor laser LD2 to convert it into weakly divergent light
  • a mirror that rotates a collimating lens (second collimating lens) CL2, a laser beam (first beam) SB1 and a laser beam (second beam) SB2 that are substantially parallel by the collimating lens CL1 and the collimating lens CL2.
  • Scanning light is projected toward the object OBJ side (FIG. 1) by the surface, and from the object OBJ that has been scanned and projected.
  • the mirror unit MU that reflects the scattered light
  • the lens LS1 that collects the scattered light (the received light beam) from the object OBJ reflected by the mirror unit MU corresponding to the first light beam, and the light that is collected by the lens LS1.
  • the photodiodes PD1 and PD2 preferably have a plurality of pixels in a direction orthogonal to the scanning direction.
  • the mirror unit MU has a shape in which two triangular pyramids are joined together in opposite directions, that is, has three pairs of mirror surfaces M1 and M2 that are inclined in a direction facing each other.
  • the inclination angle of the first mirror surface M1 with respect to the rotation axis RO is the same, but the inclination angle of the second mirror surface M2 with respect to the rotation axis RO is different.
  • the mirror surfaces M1 and M2 are preferably formed by depositing a reflective film on the surface of a resin material (for example, PC) injection-molded into the shape of the mirror unit. As a result, the tilt angles of the mirror surfaces M1 and M2 can be accurately made.
  • the mirror unit MU is connected to a motor (not shown) and is driven to rotate.
  • the semiconductor laser LD1 and the collimating lens CL1 constitute a light projection system LPS1
  • the semiconductor laser LD2 and the collimating lens CL2 constitute a light projection system LPS2
  • the lens LS1 and the photodiode PD1 constitute a light receiving system RPS1.
  • LS2 and photodiode PD2 constitute light receiving system RPS2.
  • the light projecting system LPS1 and the light receiving system RPS1 may be a single light projecting / receiving system unit
  • the light projecting system LPS2 and the light receiving system RPS2 may be a single light projecting / receiving system unit.
  • the optical axes of the light receiving systems RPS1 and RPS2 are substantially orthogonal to the rotation axis RO of the mirror unit MU.
  • the spread angles in the scanning orthogonal direction of the light beam emitted from the light projecting system LPS1 and the light beam emitted from the light projecting system LPS2 are preferably substantially equal (for example, the difference between the angles is within ⁇ 10%). good.
  • FIG. 3 is a diagram showing the laser radar LR cut in a direction perpendicular to the rotation axis RO.
  • FIG. 4 is a diagram showing the laser radar LR cut along the rotation axis RO (viewed from a direction orthogonal to the plane formed by the rotation axis RO and the scanning center C).
  • the center line of the first mirror surface M1 is a scanning center C.
  • the optical axis AX1 of the first light beam SB1 emitted from the light projecting system LPS1 and the optical axis AX2 of the second light beam SB2 emitted from the light projecting system LPS2 are the first mirror.
  • the optical axes AX1 and AX2 are preferably symmetric with respect to the scanning center C, and approach the surface M1. As a result, the apparatus can be made compact, and the light can be effectively used while suppressing the vignetting.
  • the optical axis AX1 of the first light beam SB1 emitted from the light projection system LPS1 and the optical axis AX2 of the second light beam SB2 emitted from the light projection system LPS2 are the first mirror surface. It goes away as it goes to M1.
  • the value ( ⁇ ⁇ ⁇ ) obtained by multiplying the angle ⁇ formed by the optical axis AX2 of the second light beam SB2 and the surface PL is a value of zero or less.
  • ⁇ + ⁇ 0.
  • the object can be detected in a wider range by dividing the scanning range of the first light beam SB1 and the second light beam SB2 while suppressing the influence of longitudinal distortion and beam rotation.
  • divergent light intermittently emitted from the semiconductor laser LD1 in pulses is converted into weak divergent light by the collimator lens CL1 to become the first light beam SB1, and the first mirror surface M1 of the rotating mirror unit MU. 2 is reflected at the point P2a on the right half part side (right side of the center C) shown in FIG. 2 of the second mirror surface M2 and then reflected on the external object OBJ side as a laser spot light. Scanned light is emitted.
  • the diverging light intermittently emitted in a pulse form from the semiconductor laser LD2 at a timing different from that of the semiconductor laser LD1 is converted into weak divergent light by the collimator lens CL2 to become the second light beam SB2, and the rotating mirror unit
  • the light enters the first mirror surface M1 of the MU, is reflected there, and is further reflected at a point P2b on the left half side (left side of the center C) of the second mirror surface M2 shown in FIG. Scanning light is projected on the side as laser spot light.
  • the cross section of the laser spot light beam emitted toward the object OBJ has, for example, a vertically long cross section (that is, a cross section in the direction perpendicular to the optical axis whose size in the direction corresponding to the scanning direction is smaller than the size corresponding to the scanning orthogonal direction). ing. It is preferable that the point P2a and the point P2b are separated in the direction of the rotation axis RO.
  • the longitudinal section of the first light beam SB1 has the same shape and size as the longitudinal section of the second light beam SB2, and the two overlap completely. That is, it is preferable that the light beam is incident on the point P1 of the first mirror surface M1. However, it is sufficient if at least a part of both overlap.
  • “at least partly overlaps” includes when the first light flux and the second light flux have different light emission timings, and also includes the case where at least a part of them overlaps on the assumption that they emit light simultaneously.
  • FIG. 5 is a diagram illustrating a state in which the object detection area is scanned by the first light beam SB1 and the second light beam SB2 (indicated by hatching) emitted according to the rotation of the mirror unit MU.
  • FIG. 6 is a diagram schematically showing the first light beam SB1 and the second light beam SB2 emitted from the second mirror surface M2.
  • the crossing angle is different for each pair.
  • the first light beam SB1 and the second light beam SB2 are sequentially reflected by the rotating first mirror surface M1 and second mirror surface M2.
  • the second light beam SB2 reflected by the first pair of the first mirror surface M1 and the second mirror surface M2 moves the uppermost region Ln1 of the object detection region horizontally according to the rotation of the mirror unit MU. Scanned in the direction from left to right.
  • the second light beam SB2 reflected by the second pair of the first mirror surface M1 and the second mirror surface M2 passes through the second region Ln2 from the top of the object detection region according to the rotation of the mirror unit MU. Scanned horizontally from left to right.
  • the second light beam SB2 reflected by the third pair of the first mirror surface M1 and the second mirror surface M2 passes through the third region Ln3 from the top of the object detection region according to the rotation of the mirror unit MU.
  • the cross section S2 in the scanning orthogonal direction of the second light beam SB2 reflected by each mirror pair and going to the object detection area is irradiated with no gap in the areas Ln1 to Ln3. It is preferable to have a size in the scanning orthogonal direction.
  • the first light beam SB1 reflected by the first pair of the first mirror surface M1 and the second mirror surface M2 is the fourth region of the object detection region according to the rotation of the mirror unit MU.
  • Ln4 is scanned horizontally from left to right.
  • the first light beam SB1 reflected by the second pair of the first mirror surface M1 and the second mirror surface M2 passes through the fifth region Ln5 from the top of the object detection region according to the rotation of the mirror unit MU. Scanned horizontally from left to right.
  • the first light beam SB1 reflected by the third pair of the first mirror surface M1 and the second mirror surface M2 passes through the sixth region Ln6 from the top of the object detection region according to the rotation of the mirror unit MU.
  • the first scan of the lower half (second light flux irradiation range) of the object detection area is completed.
  • the cross section S1 in the scanning orthogonal direction of the first light beam SB1 reflected by each mirror pair and traveling toward the object detection region is irradiated with no gap in the regions Ln4 to Ln6. It is preferable to have a size in the scanning orthogonal direction. Further, it is preferable that the second light beam SB2 in the region Ln3 and the first light beam SB1 in the region Ln4 are irradiated with no gap therebetween. These may partially overlap.
  • a single frame FL is obtained by combining images obtained by scanning the areas Ln1 to Ln6. Then, if the first pair of the first mirror surface M1 and the second mirror surface M2 return after one rotation of the mirror unit MU, the region from the uppermost region Ln1 to the lowermost region Ln6 again. Scanning is repeated to obtain the next frame FL.
  • a part of the scattered light scattered by hitting the object OBJ out of the first projected light beam is incident on the point P3a of the second mirror surface M2 of the mirror unit MU, and is reflected here. Further, after being reflected at the point P4a on the first mirror surface M1, it is condensed by the lens LS1 and detected by the light receiving surface of the photodiode PD1.
  • a part of the scattered light that is scattered by hitting the object OBJ out of the second light flux that has been scanned and projected is incident on the point P3b of the second mirror surface M2 of the mirror unit MU, reflected there, and further After being reflected at the point P4b of the one mirror surface M1, it is condensed by the lens LS2 and detected by the light receiving surface of the photodiode PD2.
  • the distance to the object OBJ can be obtained.
  • FIG. 7 is a cross-sectional view of a laser radar LR according to another embodiment in the direction of the rotation axis RO, but shows a state viewed from a direction orthogonal to the surface of the rotation axis RO and the scanning center, and the light receiving system is omitted.
  • the mirror unit MU has a triangular prism shape and includes three mirror surfaces M (1) to M (3) parallel to the rotation axis RO.
  • the light beam emitted from the light projecting system LPS1 is reflected by the mirror surfaces M (1), M (2), and M (3), and the first light beam SB1a toward the object detection area at the upper left of the drawing at different angles.
  • SB1b and SB1c, and the light beam emitted from the light projecting system LPS2 is also reflected by the mirror surfaces M (1), M (2), and M (3), and is directed to the object detection region at different angles.
  • the light fluxes are SB2a, SB2b, and SB2c.
  • the spread angle ⁇ 2 (not shown) in the scanning orthogonal direction between the light beam emitted from the light projecting system LPS1 and the light beam emitted from the light projecting system LPS2 is assumed to be equal.
  • Other configurations are the same as those in the above-described embodiment.
  • the angle difference between the optical axis AX1 of the light projecting system LPS1 and the optical axis AX2 of the light projecting system LPS2 is ⁇ 1, and the maximum angle difference ⁇ 3a of the first light beams SB1a, SB1b, SB1c emitted from the mirror unit MU.
  • the object detection area can be covered with almost no gap.
  • the difference in ⁇ 1 with respect to ⁇ 2 + ⁇ 3a or ⁇ 2 + ⁇ 3b is within ⁇ 10%, it can be said that the difference is approximately equal, so that the same effect can be realized.
  • FIG. 8 is a cross-sectional view of a light projecting system according to still another embodiment, and is a cross-section in the rotational axis direction of a mirror unit (not shown), and the vertical direction corresponds to the scanning orthogonal direction.
  • a common collimating lens CL is provided.
  • the distance from the optical axis X1 of the collimating lens CL to the light emitting surface center C1 of the light emitting surface LD1a of the semiconductor laser LD1 and the distance from the light emitting surface center C2 of the light emitting surface LD2a of the semiconductor laser LD2 are equal to each other.
  • the curvature of field becomes large.
  • the center of one of the semiconductor lasers is placed on the optical axis X1 of the collimator lens CL and the rest is placed on the periphery, the respective focal positions are shifted, which may make adjustment difficult. Therefore, as shown in FIG. 8, by arranging the light emitting surface center C1 of the light emitting surface LD1a and the light emitting surface center C2 of the light emitting surface LD2a at equal distances with respect to the optical axis X1 of the collimating lens CL, The focal position deviation can be reduced and the resolution can be increased.
  • P1 is an area irradiated with the first light beam SB1 emitted from the semiconductor laser LD1 and reflected by the first mirror surface
  • P1 ′ is a semiconductor laser.
  • P2 is irradiated with the first light beam SB1 emitted from the semiconductor laser LD1 and reflected by the second mirror surface.
  • P2 ′ is an area irradiated with the second light beam SB2 emitted from the semiconductor laser LD2 and reflected by the second mirror surface
  • P3 is emitted from the semiconductor laser LD1 and reflected by the third mirror surface.
  • the area irradiated with the first light beam SB1, and P3 ′ is the area irradiated with the second light beam SB2 emitted from the semiconductor laser LD2 and reflected by the third mirror surface.
  • P4 is an area irradiated with the first light beam SB1 emitted from the semiconductor laser LD1 and reflected by the fourth mirror surface
  • P4 ′ is the second light emitted from the semiconductor laser LD2 and reflected by the fourth mirror surface. This is an area irradiated with the light beam SB2.
  • the minimum distance between the light emitting surface LD1a of the semiconductor laser LD1 and the light emitting surface LD2a of the semiconductor laser LD2 is y
  • the focal length of the collimating lens CL is f
  • the size in the direction corresponding to the scanning direction is smaller than the size in the direction corresponding to the scanning orthogonal direction.
  • the cross-sectional size W in the direction corresponding to the scanning direction in the single laser light beam SB is W with respect to the cross-sectional size L in the direction corresponding to the scanning orthogonal direction.
  • W ⁇ L can be realized by transmitting light emitted from an isotropic light source through a beam shaper, a cylindrical lens, or a prism. .
  • the cross-sectional size W in the direction corresponding to the scanning direction of the whole emitted light beam group is the direction corresponding to the scanning orthogonal direction.
  • W ⁇ L is included for the cross-sectional size L.
  • FIG. 10 is a diagram schematically showing a light projecting / receiving system used for a laser radar according to another embodiment. Since the object OBJ is in the distance, the light beam SB1, the reflected light beam RB1, the light beam SB2, and the reflected light beam RB2 are Each is a light emitting / receiving coaxial structure that is substantially parallel.
  • FIG. 11 is a diagram schematically showing the light receiving surface of the photodiode PD.
  • the photodiode PD shown in FIG. 11 has a first area AR1 and a second area AR2 in which six pixels are arranged in a line. As shown in FIG.
  • the divergent light emitted intermittently in a pulse form from the semiconductor laser LD1 is converted into weak divergent light by the collimator lens CL to become the first light beam SB1, and a mirror surface (not shown)
  • the reflected light RB1 is reflected by a mirror surface (not shown), passes through the lens LS, and is received by the first region AR1 of the photodiode PD.
  • the divergent light intermittently emitted in a pulse form from the semiconductor laser LD2 is converted into weak divergent light by the collimator lens CL to become the second light beam SB2, reflected by a mirror surface (not shown), and reflected on the object OBJ.
  • the incident light beam RB2 is reflected by a mirror surface (not shown), passes through the lens LS, and is received by the second region AR2 of the photodiode PD.
  • the projection region of the light beam SB1 and the light receiving region of the reflected light beam RB1 are coaxial, and the projection region of the light beam SB2 and the light receiving region of the reflected light beam RB2 are coaxial.
  • the semiconductor laser LD1 and the first area AR1, and the semiconductor laser LD2 and the second area AR2 are coaxially arranged to project and receive light, and at least a part of the projected image overlaps in the distance.
  • each region of the photodiode PD preferably has a multi-array structure.
  • the example of FIG. 10B is a six-element array, but is not limited thereto.
  • a surface emitting VCSEL Very ⁇ Cavity ⁇ ⁇ Surface Emitting LASER
  • the angle of the light beam can be freely changed by deflecting the outgoing light with a prism. It becomes possible. Further, since the light can be emitted only in the angle of view having the light receiving sensitivity with respect to the light amount loss (in the case of the vertically long beam) that has occurred in the gap between the light receiving elements, the light receiving efficiency of the output light amount can be improved.
  • Laser radar that emits high-power light may cause eye safety problems, but it can improve safety in addition to increasing the amount of output light. In order to further increase the safety, the amount of light entering the pupil can be reduced by placing the beam expander after being emitted from the light source or after being deflected by the prism, thereby increasing the safety.
  • the present invention is not limited to the embodiments described in the specification, and other embodiments and modifications are included for those skilled in the art from the embodiments and technical ideas described in the present specification. it is obvious.
  • the description and the embodiments are for illustrative purposes only, and the scope of the present invention is indicated by the following claims.
  • the first light source and the second light source are arranged side by side so that the first light beam and the second light beam extend along a cross section passing through the rotation axis of the mirror unit. Also good.
  • the contents of the present invention described with reference to the drawings can all be applied to the embodiment, and can be applied to a flying object such as a helicopter or a security sensor installed in a building to detect a suspicious person.
  • the semiconductor laser is used as the light source.
  • the present invention is not limited to this, and it goes without saying that an LED or the like may be used as the light source.
  • the mirror unit may swing.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Electromagnetism (AREA)
  • Optical Radar Systems And Details Thereof (AREA)
  • Mechanical Optical Scanning Systems (AREA)

Abstract

Provided is an object detection device which can be made compact despite using a plurality of light sources, and whereby the detection range thereof can be enlarged. The object detection device according to the present invention is configured so that a first luminous flux emitted from a first light source and incident on a mirror surface, and a second luminous flux emitted from a second light source and incident on the mirror surface are at least partially superposed on the mirror surface, the first luminous flux and second luminous flux reflected by the mirror surface are projected toward an object while being scanned, a reflected optical flux is reflected by the mirror surface and received by a light-receiving element, and the size thereof in the direction corresponding to the scanning direction is less than the size thereof in the direction corresponding to the direction orthogonal to the scanning direction in a cross section in the direction orthogonal to the optical axis of the first luminous flux and the second luminous flux in an object detection region.

Description

対象物検出装置Object detection device
　本発明は、遠方の物体を検出することができる光走査型の対象物検出装置に関する。 The present invention relates to an optical scanning type object detection apparatus capable of detecting a distant object.
　近年、例えば自動車や警備ロボットなどの分野において、移動体における衝突防止の目的で移動体が進む範囲にある障害物を精度よく検知したいという要望がますます強くなっている。このような障害物の検知方法として、電波を発信して反射波を検出する電波式レーダーが提案されているが、解像度の観点から遠方の物体の位置を精度良く把握するのは難しいという課題がある。 In recent years, in the fields of automobiles and security robots, for example, there has been an increasing demand for accurately detecting obstacles within the range of moving objects for the purpose of preventing collisions in moving objects. As a method for detecting such an obstacle, a radio wave radar that transmits a radio wave and detects a reflected wave has been proposed. However, it is difficult to accurately grasp the position of a distant object from the viewpoint of resolution. is there.
　これに対し、ＴＯＦ（Ｔｉｍｅ　ｏｆ　Ｆｌｉｇｈｔ）方式を採用した対象物検出装置も既に開発されている。ＴＯＦ方式とは、パルス発光させたレーザー光が、物体に当たって戻ってくるまでの時間を測ることにより、当該物体までの距離を測定することができるものである。しかるに、ＴＯＦ方式を採用した対象物検出装置は、遠方の物体にレーザー光を照射した際に発生する微弱な反射光を検知するために、一般的にはＡＰＤ(アバランシェ・フォトダイオード)等の増幅率の高い受光素子を使用している。また、検知すべき対象物の解像度を上げるため、反射光を受光する複数の受光素子を配列して高分解能を確保することも行われている。 On the other hand, an object detection device adopting the TOF (Time of Flight) method has already been developed. In the TOF method, the distance to the object can be measured by measuring the time until the pulsed laser light hits the object and returns. However, the object detection device adopting the TOF method is generally used to amplify an APD (avalanche photodiode) or the like in order to detect the weak reflected light generated when a laser beam is irradiated to a distant object. A light receiving element with a high rate is used. In order to increase the resolution of an object to be detected, a plurality of light receiving elements that receive reflected light are arranged to ensure high resolution.
　特許文献１には、回転軸に対して傾いた第１ミラー面と第２ミラー面を備えた回転するミラーユニットと、前記ミラーユニットを介して、対象物に向けて光束を出射する少なくとも１つの光源を含む投光系と、を有し、前記光源から出射された光束が、前記ミラーユニットの前記第１ミラー面で反射した後、前記第２ミラー面へ向かって進行し、更に前記第２ミラー面で反射され、前記ミラーユニットの回転に応じて前記対象物に対して走査されつつ投光されるようになっているレーダーが開示されている。このようなミラーユニットを用いた場合、投光系から出射された光束が回転する第１ミラー面と第２ミラー面で反射された後に対象物に向かって照射され、ここで反射した後、再び第１ミラー面と第２ミラー面で反射された後に受光系に入射するので、原則的に投光された光の反射光のみが受光系に入射することとなり、外乱光に対する耐性を持ち、高い分解能を有し、更に広い視野を持つというメリットを有する。 Patent Document 1 discloses a rotating mirror unit having a first mirror surface and a second mirror surface that are inclined with respect to a rotation axis, and at least one that emits a light beam toward an object through the mirror unit. A light projection system including a light source, and the light beam emitted from the light source is reflected by the first mirror surface of the mirror unit and then travels toward the second mirror surface, and further the second There is disclosed a radar which is reflected by a mirror surface and projected while being scanned with respect to the object in accordance with the rotation of the mirror unit. When such a mirror unit is used, the luminous flux emitted from the light projecting system is reflected by the rotating first mirror surface and the second mirror surface, and then is irradiated toward the object. Since the light is incident on the light receiving system after being reflected by the first mirror surface and the second mirror surface, in principle, only the reflected light of the projected light is incident on the light receiving system. It has the advantage of having a resolution and a wider field of view.
特開２０１５－１８０９５６号公報Japanese Patent Laying-Open No. 2015-180956
　しかしながら特許文献１には、複数の光源を用いることで、縦歪曲を悪化させることなく走査ラインを増やせることについて開示があるものの、装置のコンパクト化を図りつつ検出範囲を拡大させることについては明確な開示がない。 However, although Patent Document 1 discloses that a plurality of light sources can be used to increase the number of scanning lines without deteriorating longitudinal distortion, it is clear that the detection range can be expanded while downsizing the apparatus. There is no disclosure.
　本発明は、上記事情に鑑みなされたものであり、複数の光源を用いながらもコンパクト化を図り、検出範囲を拡大できる対象物検出装置を提供することを目的とする。 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an object detection apparatus that can be made compact while using a plurality of light sources and can expand a detection range.
　上述した目的のうち少なくとも一つを実現するために、本発明の一側面を反映した対象物検出装置は、
　回転軸に対して異なる角度で傾いた複数のミラー面を備えた回転又は揺動するミラーユニットと、
　光束を出射する第１の光源と第２の光源を含む投光系と、
　対象物からの反射光束を受光する受光素子を含む受光系と、を有する対象物検出装置であって、
　前記第１の光源から出射され前記ミラー面に入射した第１の光束と、前記第２の光源から出射され前記ミラー面に入射した第２の光束とは，前記ミラー面上で少なくとも一部が重なっており、
　前記ミラー面で反射した前記第１の光束と前記第２の光束は、前記対象物に向かって走査されつつ投光され、その反射光束が前記ミラー面で反射して、前記受光素子に受光されるようになっており、
　対象物検出領域内における前記第１の光束と前記第２の光束の光軸直交方向断面において、走査方向に対応する方向のサイズは、走査直交方向に対応する方向のサイズより小さくなっているものである。 In order to realize at least one of the above-described objects, an object detection device reflecting one aspect of the present invention is provided.
A rotating or oscillating mirror unit having a plurality of mirror surfaces inclined at different angles with respect to the rotation axis;
A light projecting system including a first light source and a second light source for emitting a light beam;
A light receiving system including a light receiving element that receives a reflected light beam from the object, and an object detection device having:
At least a part of the first light beam emitted from the first light source and incident on the mirror surface and the second light beam emitted from the second light source and incident on the mirror surface are at least partially on the mirror surface. Overlap,
The first light beam and the second light beam reflected by the mirror surface are projected while being scanned toward the object, and the reflected light beam is reflected by the mirror surface and received by the light receiving element. It is supposed to
In the cross section in the direction perpendicular to the optical axis of the first light flux and the second light flux within the object detection region, the size in the direction corresponding to the scanning direction is smaller than the size in the direction corresponding to the scanning orthogonal direction It is.
　本発明によれば、複数の光源を用いながらもコンパクト化を図り、検出範囲を拡大できる対象物検出装置を提供することができる。 According to the present invention, it is possible to provide an object detection device that can be made compact while using a plurality of light sources and can expand the detection range.
本実施形態にかかる対象物検出装置としてのレーザーレーダーを車両に搭載した状態を示す概略図である。It is the schematic which shows the state which mounted the laser radar as a target object detection apparatus concerning this embodiment in the vehicle. 本実施形態にかかるレーザーレーダーＬＲの筐体を除く主要部を示す斜視図である。It is a perspective view which shows the principal part except the housing | casing of the laser radar LR concerning this embodiment. レーザーレーダーＬＲを回転軸ＲＯに直交する方向に切断して示す図である。It is a figure which cut | disconnects and shows the laser radar LR in the direction orthogonal to the rotating shaft RO. レーザーレーダーＬＲを回転軸ＲＯに沿って切断して示す図である。It is a figure which cuts and shows laser radar LR along rotation axis RO. ミラーユニットＭＵの回転に応じて、出射する第１の光束ＳＢ１と第２の光束ＳＢ２（ハッチングで示す）により、対象物検出領域を走査する状態を示す図である。It is a figure which shows the state which scans a target object detection area | region with 1st light beam SB1 and 2nd light beam SB2 (it shows by hatching) radiate | emitted according to rotation of the mirror unit MU. 第２ミラー面Ｍ２から出射される第１の光束ＳＢ１と第２の光束ＳＢ２を模式的に示す図である。It is a figure which shows typically 1st light beam SB1 and 2nd light beam SB2 which are radiate | emitted from the 2nd mirror surface M2. 別な実施形態にかかるレーザーレーダーＬＲの回転軸ＲＯ方向における断面図である。It is sectional drawing in the rotating shaft RO direction of the laser radar LR concerning another embodiment. 更に別な実施形態にかかる投光系の断面図である。It is sectional drawing of the light projection system concerning another embodiment. レーザー光束の断面の例を示す図である。It is a figure which shows the example of the cross section of a laser beam. 別な実施形態にかかるレーザーレーダーに用いる投受光系を模式的に示す図である。It is a figure which shows typically the light projection / reception system used for the laser radar concerning another embodiment. フォトダイオードＰＤの受光面を模式的に示す図である。It is a figure which shows typically the light-receiving surface of photodiode PD.
　以下、添付した図面を参照しながら、本発明の実施形態を説明する。図１は、本実施形態にかかる対象物検出装置としてのレーザーレーダーを車両に搭載した状態を示す概略図である。本実施形態のレーザーレーダーＬＲは、車両１のフロントウィンドウ１ａの上端内側に設けられているが、それ以外の車外（フロントグリル１ｂの背後など）に配置されていても良い。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a state in which a laser radar as an object detection device according to the present embodiment is mounted on a vehicle. The laser radar LR of the present embodiment is provided on the inner side of the upper end of the front window 1a of the vehicle 1, but may be disposed outside the vehicle (such as behind the front grill 1b).
　図２は、本実施形態にかかるレーザーレーダーＬＲの筐体を除く主要部を模式的に示す斜視図であるが、構成要素の形状や長さ等、実際と異なる場合がある。また特に示さない限り、出射光束と反射光束は光軸（光束中心）のみ示している。 FIG. 2 is a perspective view schematically showing the main part excluding the housing of the laser radar LR according to the present embodiment. However, the shape and length of the components may differ from the actual ones. Unless otherwise indicated, the outgoing light beam and the reflected light beam are shown only on the optical axis (light beam center).
　図２に示すように、レーザーレーダーＬＲは、例えばレーザー光束を出射するパルス式の半導体レーザー（第１の光源）ＬＤ１と、半導体レーザーＬＤ１からの発散光の発散角を狭め、弱発散光に変換するコリメートレンズ（第１のコリメートレンズ）ＣＬ１と、レーザー光束を出射するパルス式の半導体レーザー（第２の光源）ＬＤ２と、半導体レーザーＬＤ２からの発散光の発散角を狭め、弱発散光に変換するコリメートレンズ（第２のコリメートレンズ）ＣＬ２と、コリメートレンズＣＬ１及びコリメートレンズＣＬ２で略平行とされたレーザー光束（第１の光束）ＳＢ１及びレーザー光束（第２の光束）ＳＢ２を、回転するミラー面により対象物ＯＢＪ側（図１）に向かって走査投光すると共に、走査投光された対象物ＯＢＪからの散乱光を反射させるミラーユニットＭＵと、第１の光束に対応してミラーユニットＭＵで反射された対象物ＯＢＪからの散乱光（受光光束）を集光するレンズＬＳ１と、レンズＬＳ１により集光された光を受光するフォトダイオード（受光素子）ＰＤ１と、第２の光束に対応してミラーユニットＭＵで反射された対象物ＯＢＪからの散乱光（受光光束）を集光するレンズＬＳ２と、レンズＬＳ２により集光された光を受光するフォトダイオード（受光素子）ＰＤ２とを有する。フォトダイオードＰＤ１，ＰＤ２は、走査方向に直交する方向に複数の画素を有していると好ましい。 As shown in FIG. 2, the laser radar LR converts, for example, a pulsed semiconductor laser (first light source) LD1 that emits a laser beam and a divergent angle of divergent light from the semiconductor laser LD1 into weakly divergent light. Collimating lens (first collimating lens) CL1, pulse-type semiconductor laser (second light source) LD2 that emits a laser beam, and narrowing the divergence angle of the divergent light from the semiconductor laser LD2 to convert it into weakly divergent light A mirror that rotates a collimating lens (second collimating lens) CL2, a laser beam (first beam) SB1 and a laser beam (second beam) SB2 that are substantially parallel by the collimating lens CL1 and the collimating lens CL2. Scanning light is projected toward the object OBJ side (FIG. 1) by the surface, and from the object OBJ that has been scanned and projected. The mirror unit MU that reflects the scattered light, the lens LS1 that collects the scattered light (the received light beam) from the object OBJ reflected by the mirror unit MU corresponding to the first light beam, and the light that is collected by the lens LS1. A photodiode (light receiving element) PD1 that receives the reflected light, a lens LS2 that collects scattered light (received light beam) from the object OBJ reflected by the mirror unit MU corresponding to the second light beam, and a lens LS2 And a photodiode (light receiving element) PD2 that receives the light condensed by the light source. The photodiodes PD1 and PD2 preferably have a plurality of pixels in a direction orthogonal to the scanning direction.
　ミラーユニットＭＵは、２つの三角錐を逆向きに接合して一体化したごとき形状を有し、すなわち対になって向き合う方向に傾いたミラー面Ｍ１、Ｍ２を３対有している。本実施形態では、回転軸線ＲＯに対する第１ミラー面Ｍ１の傾き角は等しいが、回転軸線ＲＯに対する第２ミラー面Ｍ２の傾き角は、それぞれ異なっている。 The mirror unit MU has a shape in which two triangular pyramids are joined together in opposite directions, that is, has three pairs of mirror surfaces M1 and M2 that are inclined in a direction facing each other. In the present embodiment, the inclination angle of the first mirror surface M1 with respect to the rotation axis RO is the same, but the inclination angle of the second mirror surface M2 with respect to the rotation axis RO is different.
　ミラー面Ｍ１、Ｍ２は、ミラーユニットの形状に射出成形された樹脂素材（例えばＰＣ）の表面に、反射膜を蒸着することにより形成されていると好ましい。これによりミラー面Ｍ１、Ｍ２の傾き角を精度良く作り込むことができる。ミラーユニットＭＵは、不図示のモータに連結され、回転駆動されるようになっている。 The mirror surfaces M1 and M2 are preferably formed by depositing a reflective film on the surface of a resin material (for example, PC) injection-molded into the shape of the mirror unit. As a result, the tilt angles of the mirror surfaces M1 and M2 can be accurately made. The mirror unit MU is connected to a motor (not shown) and is driven to rotate.
　半導体レーザーＬＤ１とコリメートレンズＣＬ１とで投光系ＬＰＳ１を構成し、半導体レーザーＬＤ２とコリメートレンズＣＬ２とで投光系ＬＰＳ２を構成し、レンズＬＳ１とフォトダイオードＰＤ１とで受光系ＲＰＳ１を構成し、レンズＬＳ２とフォトダイオードＰＤ２とで受光系ＲＰＳ２を構成している。投光系ＬＰＳ１と受光系ＲＰＳ１を単一の投受光系ユニットとし、投光系ＬＰＳ２と受光系ＲＰＳ２を単一の投受光系ユニットとしても良い。受光系ＲＰＳ１，ＲＰＳ２の光軸は、ミラーユニットＭＵの回転軸線ＲＯに対して略直交している。投光系ＬＰＳ１から出射した光束と、投光系ＬＰＳ２から出射した光束の、走査直交方向における広がり角は略等しい（例えば両者の角度の差が±１０％以内）と好ましいが、異なっていても良い。 The semiconductor laser LD1 and the collimating lens CL1 constitute a light projection system LPS1, the semiconductor laser LD2 and the collimating lens CL2 constitute a light projection system LPS2, and the lens LS1 and the photodiode PD1 constitute a light receiving system RPS1. LS2 and photodiode PD2 constitute light receiving system RPS2. The light projecting system LPS1 and the light receiving system RPS1 may be a single light projecting / receiving system unit, and the light projecting system LPS2 and the light receiving system RPS2 may be a single light projecting / receiving system unit. The optical axes of the light receiving systems RPS1 and RPS2 are substantially orthogonal to the rotation axis RO of the mirror unit MU. The spread angles in the scanning orthogonal direction of the light beam emitted from the light projecting system LPS1 and the light beam emitted from the light projecting system LPS2 are preferably substantially equal (for example, the difference between the angles is within ± 10%). good.
　図３は、レーザーレーダーＬＲを回転軸ＲＯに直交する方向に切断して示す図である。図４は、レーザーレーダーＬＲを回転軸ＲＯに沿って切断して示す（回転軸ＲＯと走査中心Ｃからなる面に対し直交する方向から見た）図である。図３において、第１ミラー面Ｍ１の中心線を走査中心Ｃとする。ここで、図３に示すように、投光系ＬＰＳ１から出射した第１の光束ＳＢ１の光軸ＡＸ１と、投光系ＬＰＳ２から出射した第２の光束ＳＢ２の光軸ＡＸ２とは、第１ミラー面Ｍ１に向かうにつれて近づいており、好ましくは光軸ＡＸ１，ＡＸ２は走査中心Ｃを挟んで対称的となっている。これにより装置のコンパクト化を図れると共に、光束のケラレを抑えて光の有効利用を図れる。 FIG. 3 is a diagram showing the laser radar LR cut in a direction perpendicular to the rotation axis RO. FIG. 4 is a diagram showing the laser radar LR cut along the rotation axis RO (viewed from a direction orthogonal to the plane formed by the rotation axis RO and the scanning center C). In FIG. 3, the center line of the first mirror surface M1 is a scanning center C. Here, as shown in FIG. 3, the optical axis AX1 of the first light beam SB1 emitted from the light projecting system LPS1 and the optical axis AX2 of the second light beam SB2 emitted from the light projecting system LPS2 are the first mirror. The optical axes AX1 and AX2 are preferably symmetric with respect to the scanning center C, and approach the surface M1. As a result, the apparatus can be made compact, and the light can be effectively used while suppressing the vignetting.
　一方、図４に示すように、投光系ＬＰＳ１から出射した第１の光束ＳＢ１の光軸ＡＸ１と、投光系ＬＰＳ２から出射した第２の光束ＳＢ２の光軸ＡＸ２とは、第１ミラー面Ｍ１に向かうにつれて離れるようになっている。但し、回転軸ＲＯに直交する面ＰＬに対して、図４の反時計回りを正とし、時計回りを負としたときに、第１の光束ＳＢ１の光軸ＡＸ１と面ＰＬとのなす角αと、第２の光束ＳＢ２の光軸ＡＸ２と面ＰＬとのなす角βを乗じた値（α×β）は、ゼロ以下の値となっている。好ましくはα＋β＝０である。これにより、縦歪曲とビーム回転の影響を抑制しつつ、第１の光束ＳＢ１と第２の光束ＳＢ２との走査範囲を分けて、より広範囲に対象物の検出を行うことができる。 On the other hand, as shown in FIG. 4, the optical axis AX1 of the first light beam SB1 emitted from the light projection system LPS1 and the optical axis AX2 of the second light beam SB2 emitted from the light projection system LPS2 are the first mirror surface. It goes away as it goes to M1. However, the angle α formed by the optical axis AX1 of the first light beam SB1 and the surface PL when the counterclockwise direction in FIG. 4 is positive and the clockwise direction is negative with respect to the surface PL orthogonal to the rotation axis RO. The value (α × β) obtained by multiplying the angle β formed by the optical axis AX2 of the second light beam SB2 and the surface PL is a value of zero or less. Preferably α + β = 0. Thus, the object can be detected in a wider range by dividing the scanning range of the first light beam SB1 and the second light beam SB2 while suppressing the influence of longitudinal distortion and beam rotation.
　次に、レーザーレーダーＬＲの対象物検出動作について説明する。図２において、半導体レーザーＬＤ１からパルス状に間欠的に出射された発散光は、コリメートレンズＣＬ１で弱発散光に変換されて第１の光束ＳＢ１となり、回転するミラーユニットＭＵの第１ミラー面Ｍ１に入射し、ここで反射され、更に第２ミラー面Ｍ２の図２で示す右半部側（中心Ｃの右側）の点Ｐ２ａで反射した後、外部の対象物ＯＢＪ側に、レーザースポット光として走査投光される。一方、半導体レーザーＬＤ１とは異なるタイミングで、半導体レーザーＬＤ２からパルス状に間欠的に出射された発散光は、コリメートレンズＣＬ２で弱発散光に変換されて第２の光束ＳＢ２となり、回転するミラーユニットＭＵの第１ミラー面Ｍ１に入射し、ここで反射され、更に第２ミラー面Ｍ２の図２で示す左半部側（中心Ｃの左側）の点Ｐ２ｂで反射した後、外部の対象物ＯＢＪ側にレーザースポット光として走査投光される。尚、対象物ＯＢＪに向かって出射されるレーザースポット光束の断面は、例えば縦長の断面（すなわち走査方向に対応する方向のサイズが走査直交方向に対応するサイズより小さい光軸直交方向断面）を持っている。点Ｐ２ａと点Ｐ２ｂとは、回転軸ＲＯ方向に離間していると好ましい。 Next, the object detection operation of the laser radar LR will be described. In FIG. 2, divergent light intermittently emitted from the semiconductor laser LD1 in pulses is converted into weak divergent light by the collimator lens CL1 to become the first light beam SB1, and the first mirror surface M1 of the rotating mirror unit MU. 2 is reflected at the point P2a on the right half part side (right side of the center C) shown in FIG. 2 of the second mirror surface M2 and then reflected on the external object OBJ side as a laser spot light. Scanned light is emitted. On the other hand, the diverging light intermittently emitted in a pulse form from the semiconductor laser LD2 at a timing different from that of the semiconductor laser LD1 is converted into weak divergent light by the collimator lens CL2 to become the second light beam SB2, and the rotating mirror unit The light enters the first mirror surface M1 of the MU, is reflected there, and is further reflected at a point P2b on the left half side (left side of the center C) of the second mirror surface M2 shown in FIG. Scanning light is projected on the side as laser spot light. The cross section of the laser spot light beam emitted toward the object OBJ has, for example, a vertically long cross section (that is, a cross section in the direction perpendicular to the optical axis whose size in the direction corresponding to the scanning direction is smaller than the size corresponding to the scanning orthogonal direction). ing. It is preferable that the point P2a and the point P2b are separated in the direction of the rotation axis RO.
　このとき図２に示すように、第１ミラー面上にて、第１の光束ＳＢ１の縦長断面は、第２の光束ＳＢ２の縦長断面と同じ形状・大きさであって、両者は完全に重なっており、すなわち第１ミラー面Ｍ１の点Ｐ１に共に入射すると好ましい。但し、両者の少なくとも一部が重なっていれば足りる。尚、「少なくとも一部が重なる」とは、第１の光束と第２の光束の発光タイミングが異なるときは、両者を同時に発光したと仮定して少なくとも一部が重なる場合も含むものとする。 At this time, as shown in FIG. 2, on the first mirror surface, the longitudinal section of the first light beam SB1 has the same shape and size as the longitudinal section of the second light beam SB2, and the two overlap completely. That is, it is preferable that the light beam is incident on the point P1 of the first mirror surface M1. However, it is sufficient if at least a part of both overlap. Note that “at least partly overlaps” includes when the first light flux and the second light flux have different light emission timings, and also includes the case where at least a part of them overlaps on the assumption that they emit light simultaneously.
　図５は、ミラーユニットＭＵの回転に応じて、出射する第１の光束ＳＢ１と第２の光束ＳＢ２（ハッチングで示す）により、対象物検出領域を走査する状態を示す図であり、走査中心をＣとする。図６は、第２ミラー面Ｍ２から出射される第１の光束ＳＢ１と第２の光束ＳＢ２を模式的に示す図である。ここで、ミラーユニットＭＵの第１ミラー面Ｍ１と第２ミラー面Ｍ２の組み合わせにおいて、対毎に交差角が異なっている。第１の光束ＳＢ１と第２の光束ＳＢ２とは、回転する第１ミラー面Ｍ１と第２ミラー面Ｍ２にて、順次反射される。 FIG. 5 is a diagram illustrating a state in which the object detection area is scanned by the first light beam SB1 and the second light beam SB2 (indicated by hatching) emitted according to the rotation of the mirror unit MU. C. FIG. 6 is a diagram schematically showing the first light beam SB1 and the second light beam SB2 emitted from the second mirror surface M2. Here, in the combination of the first mirror surface M1 and the second mirror surface M2 of the mirror unit MU, the crossing angle is different for each pair. The first light beam SB1 and the second light beam SB2 are sequentially reflected by the rotating first mirror surface M1 and second mirror surface M2.
　まず、１番対の第１ミラー面Ｍ１と第２ミラー面Ｍ２にて反射した第２の光束ＳＢ２は、ミラーユニットＭＵの回転に応じて、対象物検出領域の一番上の領域Ｌｎ１を水平方向に左から右へと走査される。次に、２番対の第１ミラー面Ｍ１と第２ミラー面Ｍ２で反射した第２の光束ＳＢ２は、ミラーユニットＭＵの回転に応じて、対象物検出領域の上から二番目の領域Ｌｎ２を水平方向に左から右へと走査される。次に、３番対の第１ミラー面Ｍ１と第２ミラー面Ｍ２で反射した第２の光束ＳＢ２は、ミラーユニットＭＵの回転に応じて、対象物検出領域の上から三番目の領域Ｌｎ３を水平方向に左から右へと走査される。これにより対象物検出領域の上半部（第１光束照射範囲）の１回目の走査が完了する。図６に模式的に示すように、各ミラー対で反射されて対象物検出領域に向かう第２の光束ＳＢ２の走査直交方向における断面Ｓ２は、領域Ｌｎ１～Ｌｎ３において互いに隙間なく照射されるような走査直交方向のサイズを持つと好ましい。 First, the second light beam SB2 reflected by the first pair of the first mirror surface M1 and the second mirror surface M2 moves the uppermost region Ln1 of the object detection region horizontally according to the rotation of the mirror unit MU. Scanned in the direction from left to right. Next, the second light beam SB2 reflected by the second pair of the first mirror surface M1 and the second mirror surface M2 passes through the second region Ln2 from the top of the object detection region according to the rotation of the mirror unit MU. Scanned horizontally from left to right. Next, the second light beam SB2 reflected by the third pair of the first mirror surface M1 and the second mirror surface M2 passes through the third region Ln3 from the top of the object detection region according to the rotation of the mirror unit MU. Scanned horizontally from left to right. This completes the first scan of the upper half (first light beam irradiation range) of the object detection area. As schematically shown in FIG. 6, the cross section S2 in the scanning orthogonal direction of the second light beam SB2 reflected by each mirror pair and going to the object detection area is irradiated with no gap in the areas Ln1 to Ln3. It is preferable to have a size in the scanning orthogonal direction.
　これと並行して、１番対の第１ミラー面Ｍ１と第２ミラー面Ｍ２にて反射した第１の光束ＳＢ１は、ミラーユニットＭＵの回転に応じて、対象物検出領域の四番目の領域Ｌｎ４を水平方向に左から右へと走査される。次に、２番対の第１ミラー面Ｍ１と第２ミラー面Ｍ２で反射した第１の光束ＳＢ１は、ミラーユニットＭＵの回転に応じて、対象物検出領域の上から五番目の領域Ｌｎ５を水平方向に左から右へと走査される。次に、３番対の第１ミラー面Ｍ１と第２ミラー面Ｍ２で反射した第１の光束ＳＢ１は、ミラーユニットＭＵの回転に応じて、対象物検出領域の上から六番目の領域Ｌｎ６を水平方向に左から右へと走査される。これにより対象物検出領域の下半部（第２光束照射範囲）の１回目の走査が完了する。図６に模式的に示すように、各ミラー対で反射されて対象物検出領域に向かう第１の光束ＳＢ１の走査直交方向における断面Ｓ１は、領域Ｌｎ４～Ｌｎ６において互いに隙間なく照射されるような走査直交方向のサイズを持つと好ましい。又、領域Ｌｎ３における第２の光束ＳＢ２と、領域Ｌｎ４における第１の光束ＳＢ１とは、互いに隙間なく照射されると好ましい。これらは一部重なっていても良い。 In parallel with this, the first light beam SB1 reflected by the first pair of the first mirror surface M1 and the second mirror surface M2 is the fourth region of the object detection region according to the rotation of the mirror unit MU. Ln4 is scanned horizontally from left to right. Next, the first light beam SB1 reflected by the second pair of the first mirror surface M1 and the second mirror surface M2 passes through the fifth region Ln5 from the top of the object detection region according to the rotation of the mirror unit MU. Scanned horizontally from left to right. Next, the first light beam SB1 reflected by the third pair of the first mirror surface M1 and the second mirror surface M2 passes through the sixth region Ln6 from the top of the object detection region according to the rotation of the mirror unit MU. Scanned horizontally from left to right. Thereby, the first scan of the lower half (second light flux irradiation range) of the object detection area is completed. As schematically shown in FIG. 6, the cross section S1 in the scanning orthogonal direction of the first light beam SB1 reflected by each mirror pair and traveling toward the object detection region is irradiated with no gap in the regions Ln4 to Ln6. It is preferable to have a size in the scanning orthogonal direction. Further, it is preferable that the second light beam SB2 in the region Ln3 and the first light beam SB1 in the region Ln4 are irradiated with no gap therebetween. These may partially overlap.
　この領域Ｌｎ１～Ｌｎ６の走査により得られた画像を組み合わせて、１つのフレームＦＬが得られることとなる。そして、ミラーユニットＭＵが１回転した後、１番対の第１ミラー面Ｍ１と第２ミラー面Ｍ２が戻ってくれば、再び監視空間の一番上の領域Ｌｎ１から最も下の領域Ｌｎ６までの走査を繰り返し、次のフレームＦＬが得られる。 A single frame FL is obtained by combining images obtained by scanning the areas Ln1 to Ln6. Then, if the first pair of the first mirror surface M1 and the second mirror surface M2 return after one rotation of the mirror unit MU, the region from the uppermost region Ln1 to the lowermost region Ln6 again. Scanning is repeated to obtain the next frame FL.
　図２において、走査投光された第１の光束のうち対象物ＯＢＪに当たって散乱された散乱光の一部が、ミラーユニットＭＵの第２ミラー面Ｍ２の点Ｐ３ａに入射し、ここで反射され、更に第１ミラー面Ｍ１の点Ｐ４ａで反射された後、レンズＬＳ１により集光されて、フォトダイオードＰＤ１の受光面で検知される。又、走査投光された第２の光束のうち対象物ＯＢＪに当たって散乱された散乱光の一部が、ミラーユニットＭＵの第２ミラー面Ｍ２の点Ｐ３ｂに入射し、ここで反射され、更に第１ミラー面Ｍ１の点Ｐ４ｂで反射された後、レンズＬＳ２により集光されて、フォトダイオードＰＤ２の受光面で検知されることとなる。不図示の回路にて、半導体レーザーＬＤ１，ＬＤ２の出射時と、フォトダイオードＰＤの検出時との時間差を求めることで、対象物ＯＢＪまでの距離が分かる。 In FIG. 2, a part of the scattered light scattered by hitting the object OBJ out of the first projected light beam is incident on the point P3a of the second mirror surface M2 of the mirror unit MU, and is reflected here. Further, after being reflected at the point P4a on the first mirror surface M1, it is condensed by the lens LS1 and detected by the light receiving surface of the photodiode PD1. In addition, a part of the scattered light that is scattered by hitting the object OBJ out of the second light flux that has been scanned and projected is incident on the point P3b of the second mirror surface M2 of the mirror unit MU, reflected there, and further After being reflected at the point P4b of the one mirror surface M1, it is condensed by the lens LS2 and detected by the light receiving surface of the photodiode PD2. By obtaining a time difference between the emission of the semiconductor lasers LD1 and LD2 and the detection of the photodiode PD by a circuit (not shown), the distance to the object OBJ can be obtained.
　図７は別な実施形態にかかるレーザーレーダーＬＲの回転軸ＲＯ方向における断面図であるが、回転軸ＲＯと走査中心からなる面に対し直交する方向から見た状態を示し、受光系は省略している。本実施形態では、ミラーユニットＭＵが三角柱状であり、回転軸ＲＯに平行な３つのミラー面Ｍ（１）～Ｍ（３）を備えている。 FIG. 7 is a cross-sectional view of a laser radar LR according to another embodiment in the direction of the rotation axis RO, but shows a state viewed from a direction orthogonal to the surface of the rotation axis RO and the scanning center, and the light receiving system is omitted. ing. In the present embodiment, the mirror unit MU has a triangular prism shape and includes three mirror surfaces M (1) to M (3) parallel to the rotation axis RO.
　投光系ＬＰＳ１から出射した光束は、ミラー面Ｍ（１）、Ｍ（２），Ｍ（３）で反射されて，互いに異なる角度で図面左上の対象物検出領域に向かう第１の光束ＳＢ１ａ、ＳＢ１ｂ、ＳＢ１ｃとなり、また投光系ＬＰＳ２から出射した光束も、ミラー面Ｍ（１）、Ｍ（２），Ｍ（３）で反射されて，互いに異なる角度で対象物検出領域に向かう第２の光束ＳＢ２ａ、ＳＢ２ｂ、ＳＢ２ｃとなる。投光系ＬＰＳ１から出射した光束と、投光系ＬＰＳ２から出射した光束の、走査直交方向における広がり角θ２（不図示）は等しいものとする。それ以外の構成は、上述した実施形態と同様である。 The light beam emitted from the light projecting system LPS1 is reflected by the mirror surfaces M (1), M (2), and M (3), and the first light beam SB1a toward the object detection area at the upper left of the drawing at different angles. SB1b and SB1c, and the light beam emitted from the light projecting system LPS2 is also reflected by the mirror surfaces M (1), M (2), and M (3), and is directed to the object detection region at different angles. The light fluxes are SB2a, SB2b, and SB2c. The spread angle θ2 (not shown) in the scanning orthogonal direction between the light beam emitted from the light projecting system LPS1 and the light beam emitted from the light projecting system LPS2 is assumed to be equal. Other configurations are the same as those in the above-described embodiment.
　ここで、投光系ＬＰＳ１の光軸ＡＸ１と、投光系ＬＰＳ２の光軸ＡＸ２との角度差をθ１とし、ミラーユニットＭＵから出射される第１の光束ＳＢ１ａ、ＳＢ１ｂ、ＳＢ１ｃの最大角度差θ３ａとし、ミラーユニットＭＵから出射される第２の光束ＳＢ２ａ、ＳＢ２ｂ、ＳＢ２ｃの最大角度差θ３ｂとすると、θ１＝θ２＋θ３ａ、又はθ１＝θ２＋θ３ｂが成立する。これにより、ほぼ隙間なく対象物検出領域をカバーできる。但し、θ１における、θ２＋θ３ａ又はθ２＋θ３ｂに対する差が±１０％以内であれば略等しいといえるので、同様な効果を実現できる。 Here, the angle difference between the optical axis AX1 of the light projecting system LPS1 and the optical axis AX2 of the light projecting system LPS2 is θ1, and the maximum angle difference θ3a of the first light beams SB1a, SB1b, SB1c emitted from the mirror unit MU. Assuming that the maximum angle difference θ3b between the second light beams SB2a, SB2b, and SB2c emitted from the mirror unit MU, θ1 = θ2 + θ3a or θ1 = θ2 + θ3b is established. Thereby, the object detection area can be covered with almost no gap. However, if the difference in θ1 with respect to θ2 + θ3a or θ2 + θ3b is within ± 10%, it can be said that the difference is approximately equal, so that the same effect can be realized.
　図８は更に別な実施形態にかかる投光系の断面図であるが、不図示のミラーユニットの回転軸方向の断面であって、上下方向が走査直交方向に相当する。ここでは、共通のコリメートレンズＣＬを設けている。コリメートレンズＣＬの光軸Ｘ１から、半導体レーザーＬＤ１の発光面ＬＤ１ａの発光面中心Ｃ１までの距離と、半導体レーザーＬＤ２の発光面ＬＤ２ａの発光面中心Ｃ２までの距離とは互いに等しくなっている。本実施形態の場合、光源間隔を広く確保する必要があるが、コストを下げるためにレンズ枚数を少なくしようとすると、像面湾曲が大きくなってしまう。例えば片方の半導体レーザーの中心をコリメートレンズＣＬの光軸Ｘ１に置き、残りを周辺に置くと、それぞれの焦点位置がずれるから、調整が困難となる恐れがある。そこで、図８に示すように、コリメートレンズＣＬの光軸Ｘ１に対して発光面ＬＤ１ａの発光面中心Ｃ１と、発光面ＬＤ２ａの発光面中心Ｃ２とを等距離配置することで、2つの光源の焦点位置ずれを小さくでき、分解能を高くすることが可能なる。また単一のレンズで２つの受光素子を設けた受光系の場合は、受光素子面上でのボケを小さくでき光量を確保できる。尚、図８中、ミラー面を４面としたときに、Ｐ１は半導体レーザーＬＤ１から出射され第１ミラー面で反射された第１の光束ＳＢ１で照射されるエリアであり、Ｐ１’は半導体レーザーＬＤ２から出射され第１ミラー面で反射された第２の光束ＳＢ２で照射されるエリアであり、Ｐ２は半導体レーザーＬＤ１から出射され第２ミラー面で反射された第１の光束ＳＢ１で照射されるエリアであり、Ｐ２’は半導体レーザーＬＤ２から出射され第２ミラー面で反射された第２の光束ＳＢ２で照射されるエリアであり、Ｐ３は半導体レーザーＬＤ１から出射され第３ミラー面で反射された第１の光束ＳＢ１で照射されるエリアであり、Ｐ３’は半導体レーザーＬＤ２から出射され第３ミラー面で反射された第２の光束ＳＢ２で照射されるエリアであり、Ｐ４は半導体レーザーＬＤ１から出射され第４ミラー面で反射された第１の光束ＳＢ１で照射されるエリアであり、Ｐ４’は半導体レーザーＬＤ２から出射され第４ミラー面で反射された第２の光束ＳＢ２で照射されるエリアである。 FIG. 8 is a cross-sectional view of a light projecting system according to still another embodiment, and is a cross-section in the rotational axis direction of a mirror unit (not shown), and the vertical direction corresponds to the scanning orthogonal direction. Here, a common collimating lens CL is provided. The distance from the optical axis X1 of the collimating lens CL to the light emitting surface center C1 of the light emitting surface LD1a of the semiconductor laser LD1 and the distance from the light emitting surface center C2 of the light emitting surface LD2a of the semiconductor laser LD2 are equal to each other. In the case of the present embodiment, it is necessary to ensure a wide light source interval, but if the number of lenses is reduced in order to reduce the cost, the curvature of field becomes large. For example, if the center of one of the semiconductor lasers is placed on the optical axis X1 of the collimator lens CL and the rest is placed on the periphery, the respective focal positions are shifted, which may make adjustment difficult. Therefore, as shown in FIG. 8, by arranging the light emitting surface center C1 of the light emitting surface LD1a and the light emitting surface center C2 of the light emitting surface LD2a at equal distances with respect to the optical axis X1 of the collimating lens CL, The focal position deviation can be reduced and the resolution can be increased. In the case of a light receiving system in which two light receiving elements are provided with a single lens, blur on the surface of the light receiving element can be reduced and the amount of light can be secured. In FIG. 8, when there are four mirror surfaces, P1 is an area irradiated with the first light beam SB1 emitted from the semiconductor laser LD1 and reflected by the first mirror surface, and P1 ′ is a semiconductor laser. An area irradiated with the second light beam SB2 emitted from the LD2 and reflected by the first mirror surface, and P2 is irradiated with the first light beam SB1 emitted from the semiconductor laser LD1 and reflected by the second mirror surface. P2 ′ is an area irradiated with the second light beam SB2 emitted from the semiconductor laser LD2 and reflected by the second mirror surface, and P3 is emitted from the semiconductor laser LD1 and reflected by the third mirror surface. The area irradiated with the first light beam SB1, and P3 ′ is the area irradiated with the second light beam SB2 emitted from the semiconductor laser LD2 and reflected by the third mirror surface. , P4 is an area irradiated with the first light beam SB1 emitted from the semiconductor laser LD1 and reflected by the fourth mirror surface, and P4 ′ is the second light emitted from the semiconductor laser LD2 and reflected by the fourth mirror surface. This is an area irradiated with the light beam SB2.
　更に、半導体レーザーＬＤ１の発光面ＬＤ１ａと、半導体レーザーＬＤ２の発光面ＬＤ２ａとの最小距離をｙとし、コリメートレンズＣＬの焦点距離をｆとし、半導体レーザーＬＤ１から出射された第１の光束ＳＢ１と、半導体レーザーＬＤ２から出射された第２の光束ＳＢ２との走査直交方向における最小角（線Ｌ１）と最大角（線Ｌ２）との角度差をθ４とすると、２・ａｔａｎ（ｙ／２ｆ）＝θ４を満たす。これにより、ほぼ隙間なく対象物検出領域をカバーできる。但し、ａｔａｎ（ｙ／ｆ）における、θ４に対する差が±１０％以内であれば略等しいといえるので、同様な効果を実現できる。尚、走査直交方向の光束の広がり角に合わせ、ミラー面反射後の光束が略等間隔に隣り合うように、ミラーユニットＭＵを調整すると好ましい。２・ａｔａｎ（ｙ／２ｆ）＝θ３ａ又はθ３ｂとしても良い。 Further, the minimum distance between the light emitting surface LD1a of the semiconductor laser LD1 and the light emitting surface LD2a of the semiconductor laser LD2 is y, the focal length of the collimating lens CL is f, and the first light beam SB1 emitted from the semiconductor laser LD1; Assuming that the angle difference between the minimum angle (line L1) and the maximum angle (line L2) in the scanning orthogonal direction with the second light beam SB2 emitted from the semiconductor laser LD2 is θ4, 2 · atan (y / 2f) = θ4 Meet. Thereby, the object detection area can be covered with almost no gap. However, if the difference with respect to θ4 in atan (y / f) is within ± 10%, it can be said that they are substantially equal, so the same effect can be realized. Note that it is preferable to adjust the mirror unit MU so that the light beams after reflection on the mirror surface are adjacent to each other at substantially equal intervals in accordance with the spread angle of the light beams in the scanning orthogonal direction. 2 · atan (y / 2f) = θ3a or θ3b may be used.
　以上、述べた実施形態で、対象物検出領域に照射されるレーザー光束ＳＢの光軸直交方向断面において、走査方向に対応する方向のサイズが、走査直交方向に対応する方向のサイズより小さくなっているとは、例えば図９（ａ）に示すように、単一のレーザー光束ＳＢにおける走査方向に対応する方向の断面サイズＷが、走査直交方向に対応する方向の断面サイズＬに対して、Ｗ＜Ｌであることを言う。このようなレーザー光束ＳＢは、縦長光源を用いることで実現できるが、等方形の光源からの出射光をビームシェイパやシリンドリカルレンズ、あるいはプリズムなどを透過させることで、Ｗ＜Ｌを実現することができる。 As described above, in the embodiment described above, in the cross section in the direction perpendicular to the optical axis of the laser light beam SB irradiated to the object detection region, the size in the direction corresponding to the scanning direction is smaller than the size in the direction corresponding to the scanning orthogonal direction. For example, as shown in FIG. 9A, the cross-sectional size W in the direction corresponding to the scanning direction in the single laser light beam SB is W with respect to the cross-sectional size L in the direction corresponding to the scanning orthogonal direction. Say <L. Such a laser beam SB can be realized by using a vertically long light source, but W <L can be realized by transmitting light emitted from an isotropic light source through a beam shaper, a cylindrical lens, or a prism. .
　又、例えば図９（ｂ）に示すように、同時に複数の光束ＳＢが出射される場合、出射される光束群全体の走査方向に対応する方向の断面サイズＷが、走査直交方向に対応する方向の断面サイズＬに対して、Ｗ＜Ｌである場合も含めるものとする。このとき、第１の光源又は第２の光源を複数設けた上で、個々の傾きを調整して回転軸ＲＯに対して異なる出射角度で出射させたり、或いは光学系を透過させることにより、異なる角度で出射するようにしても良い。 For example, as shown in FIG. 9B, when a plurality of light beams SB are emitted at the same time, the cross-sectional size W in the direction corresponding to the scanning direction of the whole emitted light beam group is the direction corresponding to the scanning orthogonal direction. The case where W <L is included for the cross-sectional size L. At this time, it is different by providing a plurality of first light sources or second light sources and adjusting the individual inclinations so that the light beams are emitted at different emission angles with respect to the rotation axis RO or transmitted through the optical system. The light may be emitted at an angle.
　図１０は、別な実施形態にかかるレーザーレーダーに用いる投受光系を模式的に示す図であるが、対象物ＯＢＪが遠方にあるため、光束ＳＢ１と反射光束ＲＢ１，光束ＳＢ２と反射光束ＲＢ２はそれぞれほぼ平行となる投受光同軸構造である。図１１は、フォトダイオードＰＤの受光面を模式的に示す図である。図１１に示すフォトダイオードＰＤは、それぞれ６個の画素が一列に並んだ第１領域ＡＲ１と第２領域ＡＲ２とを有する。図１０（ａ）に示すように、半導体レーザーＬＤ１からパルス状に間欠的に出射された発散光は、コリメートレンズＣＬで弱発散光に変換されて第１の光束ＳＢ１となり，不図示のミラー面で反射されて対象物ＯＢＪに入射し、その反射光ＲＢ１は、不図示のミラー面で反射されてレンズＬＳを通過し、フォトダイオードＰＤの第１領域ＡＲ１にて受光される。一方、半導体レーザーＬＤ２からパルス状に間欠的に出射された発散光は、コリメートレンズＣＬで弱発散光に変換されて第２の光束ＳＢ２となり，不図示のミラー面で反射されて対象物ＯＢＪに入射し、その反射光束ＲＢ２は、不図示のミラー面で反射されてレンズＬＳを通過し、フォトダイオードＰＤの第２領域ＡＲ２にて受光される。このとき、図１０（ｂ）に示すように、光束ＳＢ１の投射領域と反射光束ＲＢ１の受光領域とは同軸であり、光束ＳＢ２の投射領域と反射光束ＲＢ２の受光領域とは同軸である。つまり半導体レーザーＬＤ１と第１領域ＡＲ１、半導体レーザーＬＤ２と第２領域ＡＲ２がそれぞれ投受光同軸配置となっており、その投影像の少なくとも一部が遠方で重なるようになっている。 FIG. 10 is a diagram schematically showing a light projecting / receiving system used for a laser radar according to another embodiment. Since the object OBJ is in the distance, the light beam SB1, the reflected light beam RB1, the light beam SB2, and the reflected light beam RB2 are Each is a light emitting / receiving coaxial structure that is substantially parallel. FIG. 11 is a diagram schematically showing the light receiving surface of the photodiode PD. The photodiode PD shown in FIG. 11 has a first area AR1 and a second area AR2 in which six pixels are arranged in a line. As shown in FIG. 10A, the divergent light emitted intermittently in a pulse form from the semiconductor laser LD1 is converted into weak divergent light by the collimator lens CL to become the first light beam SB1, and a mirror surface (not shown) The reflected light RB1 is reflected by a mirror surface (not shown), passes through the lens LS, and is received by the first region AR1 of the photodiode PD. On the other hand, the divergent light intermittently emitted in a pulse form from the semiconductor laser LD2 is converted into weak divergent light by the collimator lens CL to become the second light beam SB2, reflected by a mirror surface (not shown), and reflected on the object OBJ. The incident light beam RB2 is reflected by a mirror surface (not shown), passes through the lens LS, and is received by the second region AR2 of the photodiode PD. At this time, as shown in FIG. 10B, the projection region of the light beam SB1 and the light receiving region of the reflected light beam RB1 are coaxial, and the projection region of the light beam SB2 and the light receiving region of the reflected light beam RB2 are coaxial. In other words, the semiconductor laser LD1 and the first area AR1, and the semiconductor laser LD2 and the second area AR2 are coaxially arranged to project and receive light, and at least a part of the projected image overlaps in the distance.
　フォトダイオードＰＤは、独立した２チップ（６画素ずつ）を並べても良いし、図１０（ｂ）に示すように１チップが領域分割されていても良い。フォトダイオードＰＤの各領域はマルチアレイ構造になっていると好ましい。図１０（ｂ）の例は6素子アレイであるがそれに限らない。このように多画素化することにより高分解能化が可能で、少画素でも長距離の測距が可能になる。 In the photodiode PD, two independent chips (6 pixels each) may be arranged, or one chip may be divided into regions as shown in FIG. Each region of the photodiode PD preferably has a multi-array structure. The example of FIG. 10B is a six-element array, but is not limited thereto. By increasing the number of pixels in this way, it is possible to increase the resolution, and it is possible to measure a long distance even with a small number of pixels.
　又、図示していないが、広がり角の少ない面発光VCSEL（Vertical Cavity Surface Emitting LASER）をアレイ状にし，出射光をプリズムで偏角することにより、自由に複数ある光束の角度を変更することが可能になる。また、受光素子のギャップで起こっていた、光量ロス（縦長ビームの場合）に対し、受光感度を持つ画角にのみ光を出すことができるため、出力光量の受光効率の向上が可能になる。高出力の光を出射するレーザーレーダーは、アイセーフティ上の課題が生じる場合があるが、出力光量の効率化に加えて安全性を高めることができる。さらに安全性を高めるには、ビームエキスパンダを光源の出射後またはプリズムで偏角された後に置くことにより、瞳に入る光量を少なくでき、安全性を高めることが可能になる。 In addition, although not shown in the figure, a surface emitting VCSEL (Vertical 光束 Cavity に し Surface Emitting LASER) with a small divergence angle is arranged in an array shape, and the angle of the light beam can be freely changed by deflecting the outgoing light with a prism. It becomes possible. Further, since the light can be emitted only in the angle of view having the light receiving sensitivity with respect to the light amount loss (in the case of the vertically long beam) that has occurred in the gap between the light receiving elements, the light receiving efficiency of the output light amount can be improved. Laser radar that emits high-power light may cause eye safety problems, but it can improve safety in addition to increasing the amount of output light. In order to further increase the safety, the amount of light entering the pupil can be reduced by placing the beam expander after being emitted from the light source or after being deflected by the prism, thereby increasing the safety.
　本発明は、明細書に記載の実施形態に限定されるものではなく、他の実施形態・変形例を含むことは、本明細書に記載された実施形態や技術思想から本分野の当業者にとって明らかである。明細書の記載及び実施形態は、あくまでも例証を目的としており、本発明の範囲は後述するクレームによって示されている。例えば、全ての実施形態において、ミラーユニットの回転軸を通る断面に沿って第１の光束と第２の光束とが延在するように、第１の光源と第２の光源を並べて配置しても良い。又、図面を用いて説明した本発明の内容は、全て実施形態に適用でき、ヘリコプターなどの飛行体への搭載や、建物に設置して不審者を検知する防犯センサなどにも適用できる。また、上述の実施形態では、光源として半導体レーザーを用いたもので説明したが、これに限るものでなく、光源にＬＥＤ等を用いたものであってもよいのは言うまでもない。ミラーユニットは回転する例を示したが、揺動するものでも良い。 The present invention is not limited to the embodiments described in the specification, and other embodiments and modifications are included for those skilled in the art from the embodiments and technical ideas described in the present specification. it is obvious. The description and the embodiments are for illustrative purposes only, and the scope of the present invention is indicated by the following claims. For example, in all the embodiments, the first light source and the second light source are arranged side by side so that the first light beam and the second light beam extend along a cross section passing through the rotation axis of the mirror unit. Also good. The contents of the present invention described with reference to the drawings can all be applied to the embodiment, and can be applied to a flying object such as a helicopter or a security sensor installed in a building to detect a suspicious person. In the above-described embodiment, the semiconductor laser is used as the light source. However, the present invention is not limited to this, and it goes without saying that an LED or the like may be used as the light source. Although the example in which the mirror unit rotates is shown, the mirror unit may swing.
１　　　　　　　　車両
１ａ　　　　　　　フロントウィンドウ
１ｂ　　　　　　　フロントグリル
ＣＬ　　　　　　　共通のコリメートレンズ
ＣＬ１　　　　　　コリメートレンズ
ＣＬ２　　　　　　コリメートレンズ
ＦＬ　　　　　　　フレーム
ＬＤ１　　　　　　半導体レーザー
ＬＤ１ａ　　　　　発光面
ＬＤ２　　　　　　半導体レーザー
ＬＤ２ａ　　　　　発光面
Ｌｎ１－Ｌｎ６　　領域
ＬＰＳ１　　　　　投光系
ＬＰＳ２　　　　　投光系
ＬＲ　　　　　　　レーザーレーダー
ＬＳ１、ＬＳ２　　レンズ
Ｍ１　　　　　　　ミラー面
Ｍ２　　　　　　　ミラー面
ＭＵ　　　　　　　ミラーユニット
ＰＤ１、ＰＤ２　　フォトダイオード
ＲＯ　　　　　　　回転軸
ＲＰＳ１、ＲＰＳ２　　受光系
ＳＢ１、ＳＢ２　　レーザー光束
Ｗ　　　　　　　　断面サイズ 1 vehicle 1a front window 1b front grill CL common collimating lens CL1 collimating lens CL2 collimating lens FL frame LD1 semiconductor laser LD1a light emitting surface LD2 semiconductor laser LD2a light emitting surface Ln1-Ln6 region LPS1 light projecting system LPS2 light projecting system LR laser radar LS1, LS2 Lens M1 Mirror surface M2 Mirror surface MU Mirror unit PD1, PD2 Photo diode RO Rotating axis RPS1, RPS2 Light receiving system SB1, SB2 Laser beam W Cross section size

Claims (11)

  1. 　回転軸に対して異なる角度で傾いた複数のミラー面を備えた回転又は揺動するミラーユニットと、
    　光束を出射する第１の光源と第２の光源を含む投光系と、
    　対象物からの反射光束を受光する受光素子を含む受光系と、を有する対象物検出装置であって、
    　前記第１の光源から出射され前記ミラー面に入射した第１の光束と、前記第２の光源から出射され前記ミラー面に入射した第２の光束とは，前記ミラー面上で少なくとも一部が重なっており、
    　前記ミラー面で反射した前記第１の光束と前記第２の光束は、前記対象物に向かって走査されつつ投光され、その反射光束が前記ミラー面で反射して、前記受光素子に受光されるようになっており、
    　対象物検出領域内における前記第１の光束と前記第２の光束の光軸直交方向断面において、走査方向に対応する方向のサイズは、走査直交方向に対応する方向のサイズより小さくなっている対象物検出装置。     A rotating or oscillating mirror unit having a plurality of mirror surfaces inclined at different angles with respect to the rotation axis;
    A light projecting system including a first light source and a second light source for emitting a light beam;
    A light receiving system including a light receiving element that receives a reflected light beam from the object, and an object detection device having:
    At least a part of the first light beam emitted from the first light source and incident on the mirror surface and the second light beam emitted from the second light source and incident on the mirror surface are at least partially on the mirror surface. Overlap,
    The first light beam and the second light beam reflected by the mirror surface are projected while being scanned toward the object, and the reflected light beam is reflected by the mirror surface and received by the light receiving element. It is supposed to
    An object whose size in the direction corresponding to the scanning direction is smaller than the size in the direction corresponding to the scanning orthogonal direction in the cross section in the direction perpendicular to the optical axis of the first light flux and the second light flux in the object detection region Object detection device.
  2. 　前記ミラーユニットの回転軸方向に見たときに、前記第１の光源から出射した前記第１の光束の光軸と、前記第２の光源から出射した前記第２の光束の光軸とは、前記ミラー面に向かうにつれて近づく請求項１に記載の対象物検出装置。 When viewed in the rotation axis direction of the mirror unit, the optical axis of the first light beam emitted from the first light source and the optical axis of the second light beam emitted from the second light source are: The object detection apparatus according to claim 1, wherein the object detection apparatus approaches the mirror surface.
  3. 　前記ミラーユニットの回転軸と走査中心からなる面に対し直交する方向から見たときに、前記第１の光源から出射した前記第１の光束の光軸と、前記第２の光源から出射した前記第２の光束の光軸とは、前記ミラー面に向かうにつれて離れる請求項１に記載の対象物検出装置。 The optical axis of the first light flux emitted from the first light source and the light emitted from the second light source when viewed from a direction perpendicular to the plane consisting of the rotation axis of the mirror unit and the scanning center. 2. The object detection device according to claim 1, wherein the optical axis of the second light beam is separated from the optical axis of the second light beam toward the mirror surface.
  4. 　前記ミラーユニットの回転軸と走査中心からなる面に対し直交する方向から見たときに、前記第１の光源から出射した前記第１の光束の光軸と、前記第２の光源から出射した前記第２の光束の光軸との角度差θ１は、前記第１の光束の広がり角又は前記第２の光束の広がり角θ２と、前記複数のミラー面で反射後に生じる前記第１の光束又は前記第２の光束の最大角度差θ３との和に略等しい請求項３に記載の対象物検出装置。 The optical axis of the first light flux emitted from the first light source and the light emitted from the second light source when viewed from a direction perpendicular to the plane consisting of the rotation axis of the mirror unit and the scanning center. The angle difference θ1 with respect to the optical axis of the second light flux is the spread angle of the first light flux or the spread angle θ2 of the second light flux, and the first light flux generated after reflection by the plurality of mirror surfaces or the The object detection device according to claim 3, wherein the object detection device is substantially equal to a sum of the second beam and the maximum angle difference θ3.
  5. 　前記複数のミラー面は、前記回転軸と交差する方向に傾斜し所定の角度で向き合う複数対の第１ミラー面と第２ミラー面とからなり、前記第１ミラー面と前記第２ミラー面の交差角が対毎に異なっている請求項１～４のいずれかに記載の対象物検知装置。 The plurality of mirror surfaces are composed of a plurality of pairs of first mirror surfaces and second mirror surfaces that are inclined in a direction intersecting the rotation axis and face at a predetermined angle, and the first mirror surface and the second mirror surface The object detection apparatus according to any one of claims 1 to 4, wherein the crossing angle is different for each pair.
  6. 　前記投光系は、前記第１の光源から出射された前記第１の光束を透過する第１のコリメートレンズと、前記第２の光源から出射された前記第２の光束を透過する第２のコリメートレンズとを有する請求項５に記載の対象物検知装置。 The light projecting system includes a first collimating lens that transmits the first light beam emitted from the first light source, and a second light beam that transmits the second light beam emitted from the second light source. The target object detection apparatus of Claim 5 which has a collimating lens.
  7. 　前記投光系は、前記第１の光源から出射された前記第１の光束を透過し、また前記第２の光源から出射された前記第２の光束を透過する共通のコリメートレンズを有する請求項１～４のいずれかに記載の対象物検知装置。 The light projecting system includes a common collimator lens that transmits the first light beam emitted from the first light source and transmits the second light beam emitted from the second light source. 5. The object detection device according to any one of 1 to 4.
  8. 　前記第１の光源と前記第２の光源とは、前記共通のコリメートレンズの光軸に対して対称的に配置される請求項７に記載の対象物検知装置。 The object detection device according to claim 7, wherein the first light source and the second light source are arranged symmetrically with respect to an optical axis of the common collimating lens.
  9. 　前記第１の光源の発光面と，前記第２の光源の発光面との最小距離をｙとし、前記共通コリメートレンズの焦点距離をｆとしたときに、２・ａｔａｎ（ｙ／２ｆ）が、前記ミラー面で反射後に生じる前記第１の光束又は前記第２の光束の最大角度差θ４に略等しくなる請求項７又は８に記載の対象物検出装置。 When the minimum distance between the light emitting surface of the first light source and the light emitting surface of the second light source is y and the focal length of the common collimating lens is f, 2 · atan (y / 2f) is 9. The object detection device according to claim 7, wherein the object detection device is substantially equal to a maximum angle difference θ <b> 4 of the first light flux or the second light flux generated after reflection on the mirror surface.
  10. 　前記第１の光源と前記第２の光源は、それぞれ異なるタイミングで発光されるパルスレーザーである請求項１～９のいずれかに記載の対象物検知装置。 10. The object detection apparatus according to claim 1, wherein the first light source and the second light source are pulse lasers that emit light at different timings.
  11. 　前記第１の光源から出射された前記第１の光束と，前記第２の光源から出射された前記第２の光束の前記走査直交方向に対応する方向の広がり角は略等しい請求項１～１０のいずれかに記載の対象物検知装置。 11. The spread angles in the direction corresponding to the scanning orthogonal direction of the first light beam emitted from the first light source and the second light beam emitted from the second light source are substantially equal. The target object detection apparatus in any one of.
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