JP2020060408A - Projection device and distance measuring device - Google Patents

Abstract

To provide a projection device having a light reflection element with a rotating reflection surface, the projection device allowing a light to be projected to a desired direction over a wide range, and a distance measuring device having the projection device.SOLUTION: The present invention includes: a light source 11 emitting light; a deflection element 12 for deflecting light in various directions; and a reflection element 13 having a reflection surface rotating around an axis of rotation, reflecting a light having gone through the deflection element, and forming an angle to the axis of rotation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light projecting device that projects light and a distance measuring device that performs optical distance measurement.

  2. Description of the Related Art Conventionally, there is known a distance measuring device that measures a distance to an object by irradiating the object with light and detecting light reflected by the object. Further, there is known an optical scanning distance measuring device capable of performing optical scanning of an object and obtaining information on the shape and orientation of the object in addition to the distance to the object. For example, in Patent Document 1, a light projection including a mirror unit having a first mirror surface and a second mirror surface inclined with respect to a rotation axis and at least one light source for emitting a light beam toward the first mirror surface. And a scanning optical system having a system.

International Publication No. 2016/056545

  The scanning distance measuring device has, for example, a light projecting unit that projects pulsed light toward a scanning region. Then, the distance measuring device obtains the scanning information in the scanning region by using each irradiated area of the pulsed light seen from the light projecting portion as a distance measuring point and receiving light from each of the distance measuring points.

  Considering that the scanning region is scanned without omission and without waste, it is preferable that there is no region in the scanning region to which the pulsed light is not applied and that there is no region to which the pulsed light is overlapped and irradiated.

  For example, the light projecting unit is configured to reflect light by a rotating mirror and project the reflected light toward a scanning region. Further, by projecting light using a rotating mirror having a plurality of light reflecting surfaces that are inclined with respect to the rotating shaft and have different inclination angles, the light is emitted along the axial direction of the rotating shaft. The reflection direction of can be changed. As a result, the light projection area of the pulsed light can be expanded along the axial direction of the rotation axis, and the scanning area can be expanded.

  However, when the light reflection surface inclined with respect to the rotation axis is rotated around the rotation axis and the light is incident on the light reflection surface, the direction of the light reflected by the light reflection surface is changed. It changes three-dimensionally. As a result, for example, when a rotating mirror having the plurality of light reflecting surfaces is used, the intervals between the light projecting positions of the pulsed light may vary near the ends of the scanning region.

  In this case, a region where the pulsed light is not projected may be formed in the scanning region, and a region where the pulsed light is projected may be formed overlappingly for a plurality of times. In other words, an area in which the scanning accuracy (distance measurement accuracy) is reduced may be formed in the scanning area.

  Therefore, for example, even when using a rotating mirror having a light reflecting surface inclined with respect to the rotating shaft, it is preferable that light can be stably projected in a desired direction over a wide range. Further, it is preferable that the distance measurement can be performed with high accuracy over a wide range.

  The present invention has been made in view of the above points, and includes a light reflecting element having a rotating reflecting surface, and a light projecting device capable of projecting light in a desired direction over a wide range. One of the objects is to provide a distance measuring device including the light projecting device.

  According to a first aspect of the present invention, there is provided a light source that emits light, a deflection element that deflects the light in a directionally variable direction, a rotation axis that rotates about a rotation axis, reflects light that has passed through the deflection element, and a rotation axis. And a reflective element having a reflective surface with an angle.

  The invention according to claim 7 is the light projecting device according to claim 1, a light receiving element for receiving reflected light that is light projected through a reflecting element and reflected by an object, and a light receiving element. And a distance measuring unit that measures the distance to the object based on the reception result of the reflected light.

FIG. 1 is a diagram showing an overall configuration of a distance measuring device according to a first embodiment. 3 is a perspective view of a deflecting element in the distance measuring apparatus according to Embodiment 1. FIG. FIG. 3 is a perspective view of a reflective element in the distance measuring device according to the first embodiment. FIG. 3 is a diagram showing a light reflection mode of a reflecting element in the distance measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing a light reflection mode of a reflecting element in the distance measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing a light reflection mode of a reflecting element in the distance measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing a light deflection mode by a deflection element in the distance measuring apparatus according to the first embodiment. FIG. 5 is a diagram showing a change in a normal vector when a reflecting element in the distance measuring apparatus according to the first embodiment is rotated. 6A and 6B are diagrams showing changes in the reflection angle of light at a reflecting element in the distance measuring apparatus according to the first embodiment. FIG. 3 is a diagram showing a projection area of scanning light in the distance measuring apparatus according to the first embodiment. It is a figure which shows the change of the reflection angle of the light in the reflective element in the distance measuring device which concerns on a comparative example. It is a figure which shows the projection area of the scanning light in the distance measuring device which concerns on a comparative example. FIG. 6 is a diagram showing an overall configuration of a distance measuring device according to a second embodiment. FIG. 8 is a diagram showing a scanning light projection area in the distance measuring apparatus according to the second embodiment. FIG. 6 is a diagram showing an example of control of a light deflection mode by a deflection element in the distance measuring apparatus according to the second embodiment. FIG. 6 is a diagram showing an example of control of a light deflection mode by a deflection element in the distance measuring apparatus according to the second embodiment. FIG. 7 is a diagram showing a configuration of a light receiving element in the distance measuring device according to the second embodiment.

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

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

  First, the distance measuring device 10 includes a light source 11 that generates and emits pulsed light (hereinafter, referred to as primary light) L1. In the present embodiment, the light source 11 generates laser light having a peak wavelength in the infrared region as the primary light L1 and emits this laser light intermittently.

  The distance measuring device 10 has a deflecting element 12 that variably deflects the primary light L1 emitted from the light source 11. The deflection element 12 performs a periodic operation to periodically change the deflection direction of the primary light L1. The deflecting element 12 bends the traveling direction of the primary light L1 while emitting the primary light L1 and periodically changes the bending direction. The deflection element 12 emits the deflected primary light L1 as secondary light L2.

  In the present embodiment, the deflection element 12 has a swing mirror ML1 that swings around one swing axis AX and reflects the primary light L1. In the present embodiment, the deflection element 12 periodically changes the reflection direction of the primary light L1 as the oscillating mirror ML1 oscillates. In this embodiment, the deflection element 12 emits the primary light L1 reflected by the oscillating mirror ML1 as the secondary light L2.

  The distance measuring device 10 has a reflection element 13 that rotates around a rotation axis AY and that has at least one reflection surface ML2 that reflects the secondary light L2, that is, the primary light L1 that has passed through the deflection element 12. At least one of the reflection surfaces ML2 of the reflection element 13 is arranged so as to form an angle with respect to the rotation axis AY. For example, the reflective element 13 includes a polygon mirror having three reflective surfaces ML2.

  In the present embodiment, each of the reflecting surfaces ML2 of the reflecting element 13 has a rotation axis AY as an axis extending in a direction perpendicular to the axis of the swing axis AX on which the swing mirror ML1 of the deflecting element 12 swings. It rotates around the rotation axis AY. The emitting direction of the secondary light L2 is periodically changed by being reflected by the rotating reflecting surface ML2.

  In this embodiment, the secondary light L2 that has passed through the reflection element 13 is projected as scanning light (hereinafter, referred to as tertiary light) L3 toward the scanning region R0. That is, the reflective element 13 functions as a light projecting element that projects the secondary light L2 toward the scanning region R0 as the tertiary light L3 while deflecting (reflecting) the secondary light L2 in a directionally variable manner by the reflective surface ML2.

  The scanning region R0 is a virtual three-dimensional space in which the tertiary light L3 that is the primary light L1 that has passed through the deflection element 12 and the reflection element 13 is projected. In FIG. 1, the outer edge of the scanning region R0 is schematically shown by a broken line.

  For example, the scanning region R0 has a height direction (hereinafter referred to as a first direction) corresponding to the angle of the reflection surface ML2 of the reflection element 13 with respect to the rotation axis AY and the change of the normal vector when the secondary light L2 is incident. A directional range along D1 and a directional range along a width direction (hereinafter, referred to as a second direction) D2, and a range in a distance direction (depth range) in which the tertiary light L3 can maintain a predetermined intensity, Can be defined as a conical space with.

  Further, when a virtual plane distant from the reflective element 13 in the scanning region R0 by a predetermined distance is set as the scanning plane R1, the scanning plane R1 is two-dimensionally spread along the first and second directions D1 and D2. Can be defined as an area. The tertiary light L3 is projected toward the scanning region R0 so as to scan the scanning surface R1.

  Further, as shown in FIG. 1, when an object OB (that is, an object or a substance having a reflectivity or a scattering property with respect to the primary light L1) is present in the scanning region R0, the tertiary light L3 is an object OB. Is reflected or scattered by. A part of the scanning light L3 reflected by the object OB is a reflected light (hereinafter sometimes referred to as a fourth order light) L4, and an optical path almost the same as the third order light L3 is called a third order light L3. It travels in the opposite direction and returns to the reflective element 13.

  The fourth-order light L4 is deflected by the reflective element 13. That is, in this embodiment, the reflecting element 13 projects the secondary light L2, which is the primary light L1 that has passed through the deflecting element 12, as the tertiary light L3 while deflecting the light in a variable direction, and is reflected by the object OB. It also functions as a scanning element that receives and deflects the fourth-order light L4 that is the third-order light L3. After being deflected by the reflecting element 13, the fourth-order light L4 travels in a direction substantially opposite to that of the second-order light L2 in the almost same optical path as the second-order light L2.

  The distance measuring device 10 includes a light receiving optical system 14 that collects the fourth order light L4, and a light receiving element 15 that receives the fourth order light L4 collected by the light receiving optical system 14. The light receiving optical system 14 includes, for example, at least one lens. Further, the light receiving element 15 includes at least one detection element that detects the fourth-order light L4. The light receiving element 15 receives the quaternary light L4 and generates an electric signal according to the quaternary light L4.

  The light receiving element 15 generates the electric signal as a detection result (light reception result) of the fourth-order light L4. That is, the distance measuring device 10 generates the electric signal generated by the light receiving element 15 as the scanning result of the scanning region R0.

  In this embodiment, the distance measuring device 10 is provided on the optical path of the secondary light L2 between the deflecting element 12 and the reflecting element 13, and is a separation element for separating the secondary light L2 and the quaternary light L4. Have 16. For example, the separation element 16 includes a beam splitter or a perforated mirror that separates the secondary light L2 and the quaternary light L4 by reflecting the secondary light L2 and transmitting the quaternary light L4.

  The distance measuring device 10 has a control unit 20 that drives the light source 11, the deflecting element 12, the reflecting element 13, and the light receiving element 15 and controls them. The control unit 20 includes a light source control unit 21 that drives and controls the light source 11, a deflection element control unit 22 that drives and controls the deflection element 12, and a reflection element control unit 23 that drives and controls the reflection element 13. With.

  The control unit 20 also includes a distance measuring unit 24 that measures the distance to the object OB based on the light reception result of the fourth-order light L4 by the light receiving element 15. In the present embodiment, the distance measuring unit 24 detects a pulse indicating the fourth order light L4 from the electric signal generated by the light receiving element 15. Further, the distance measuring unit 24 uses the time-of-flight method based on the time difference between the projection timing of the tertiary light L3 and the reception timing of the quaternary light L4 to reach the object OB (or a partial surface area thereof). To measure the distance. Further, the distance measuring unit 24 generates data indicating the measured distance information (distance measuring data).

  Further, in the present embodiment, the distance measuring unit 24 distinguishes the scanning region R0 (scanning surface R1) into a plurality of distance measuring points (scanning points), and the distance measuring results (distances) of each of the plurality of distance measuring points. An image (distance-measuring image) of the scanning region R0 in which (value) is shown as a pixel is generated. In the present embodiment, the distance measuring unit 24 associates the distance measuring point with the information indicating the displacement of the reflecting surface ML2 of the reflecting element 13 to generate image data indicating the two-dimensional map or the three-dimensional map of the scanning region R0. To generate.

  Further, the distance measuring unit 24 uses, for example, a change cycle of the projection direction of the tertiary light L3, that is, a scanning cycle that is a cycle of scanning the scanning region R0 as a distance measurement image generation cycle, and one for each scanning cycle. Generate a ranging image. Further, the distance measuring unit 24 may have a display unit (not shown) that displays the generated plurality of distance measuring images as moving images in time series.

  Note that the scanning cycle means, for example, when the distance measuring device 10 periodically performs optical scanning on the scanning region R0, the predetermined displacement of the reflecting surface ML2 of the reflective element 13 returns to the predetermined displacement thereafter. Until the term.

  FIG. 2 is a perspective view of the deflection element 12. In the present embodiment, the deflection element 12 is a MEMS (Micro Electro Mechanical System) mirror having an oscillating mirror ML1. First, in the present embodiment, the deflection element 12 has a frame portion 12A and a swing portion 12B that is supported by the frame portion 12A and swings around the swing axis AX. The swinging portion 12B has a pair of torsion bars TX, one end of which is fixed to the inner peripheral portion of the frame portion 12A, extends along the swinging axis AX, and has elasticity in the circumferential direction of the swinging axis AX.

  Further, the swing portion 12B has a swing plate SP connected to the other ends of the pair of torsion bars TX so as to swing around the swing axis AX inside the pair of torsion bars TX. The rocking plate SP rocks around the rocking axis AX by twisting the pair of torsion bars TX along the circumferential direction of the rocking axis AX.

  The deflecting element 12 also generates, for example, a swinging force (that is, a driving force of the swinging portion 12B) that swings the swinging plate SP1 electromagnetically, electrostatically, piezoelectrically, or thermally (a driving force generating unit (FIG. 1)). (Not shown). The deflection element control unit 22 of the control unit 20 is connected to an external connection terminal (not shown) of the driving force generation unit. The oscillating unit 12B oscillates upon receiving a drive signal from the deflection element control unit 22.

  The deflecting element 12 also has a light reflecting film 12C formed on the oscillating plate SP. The light reflection film 12C swings around the swing axis AX as the swing plate SP swings. In the present embodiment, the light reflection film 12C functions as the oscillating mirror ML1 in the deflection element 12.

  FIG. 3 is a perspective view of the reflective element 13. In the present embodiment, the reflecting element 13 is a polygon mirror having three reflecting surfaces ML20, ML21 and ML22 which rotate about the rotation axis AY. In the present embodiment, the reflecting element 13 has a rotating body 13A that rotates around the rotation axis AY, and a reflecting body 13B that is fixed to the rotating body 13A and that rotates together with the rotating body 13A.

  The reflector 13B has three side surfaces S0, S1 and S2 whose angles with the rotation axis AY are different from each other. The three side surfaces S0 to S2 of the reflector 13B function as the reflecting surfaces ML20, ML21, and ML22 of the reflecting element 13, respectively.

  In the present embodiment, the reflecting surface ML20 is a plane extending parallel to the rotation axis AY, and is a plane having an angle of 0 ° with the rotation axis AY. The reflective surface ML20 functions as a reference reflective surface in the reflective element 13. On the other hand, the reflection surface ML21 and the reflection surface ML22 are flat surfaces that are angled with respect to the rotation axis AY.

  Therefore, in this embodiment, the normal line N0 of the first reflecting surface ML20 extends in the direction perpendicular to the rotation axis AY. Further, each of the normal line N1 of the reflecting surface ML21 and the normal line N2 of the reflecting surface ML22 extends with a component along the axial direction of the rotation axis AY. In the following, the reflective surface ML20 may be referred to as a reference reflective surface, and the reflective surfaces ML21 and ML22 may be referred to as first and second reflective surfaces, respectively.

  In the present embodiment, the first and second reflecting surfaces ML21 and ML22 are configured to have normals N1 and N2 having mutually opposite components along the rotation axis AY. There is. Therefore, the first and second reflecting surfaces ML21 and ML22 are inclined in the opposite directions with respect to the reference reflecting surface ML20.

  4A, 4B and 4C show the paths of the secondary light L2 and the tertiary light L3 during the period in which the secondary light L2 is incident on the reference reflective surface ML20 and the first and second reflective surfaces ML21 and ML22, respectively. It is a figure which shows typically about the outline.

  Below, the secondary light L2 incident on the reference reflection surface ML20 is referred to as the secondary light L20, and the secondary light L20 reflected by the reference reflection surface ML20 is referred to as the tertiary light L30. Further, a period during which the secondary light L20 is incident on the reference reflection surface ML20 is referred to as a reference period P0.

  Similarly, the secondary lights L2 incident on the first and second reflecting surfaces ML21 and ML22 are referred to as secondary lights L21 and L22, respectively, and the secondary lights reflected by the first and second reflecting surfaces ML21 and ML22. L21 and L22 are referred to as third-order lights L31 and L32, respectively. The periods in which the secondary lights L21 and L22 are incident on the first and second reflecting surfaces ML21 and ML22 are referred to as first and second periods P1 and P2, respectively.

  Further, in FIGS. 4A to 4C, for the sake of clarity, the secondary lights L20 to L22 are optical axes along the direction perpendicular to the rotation axis AY during each period, which is the reference reflection surface in the present embodiment. A case will be described in which light enters each of the reflecting surfaces ML20, ML21, and ML22 along the optical axis along the same direction as the vector of the normal line N0 of the ML20.

  Further, in FIGS. 4A to 4C, the vectors of the normal lines N0, N1 and N2 in each of the reference reflection surface ML20 and the first and second reflection surfaces ML21 and ML22 are components along the optical axis of the secondary light L2. And the case of being arranged at a position having only a component along the rotation axis AY.

  Further, in the present embodiment, as shown in FIG. 4, the direction along the axial direction of the rotation axis AY is the z direction. Further, the direction along the vector of the normal line N0 of the reference reflection surface ML20 in the state where the reference reflection surface ML20 is at a predetermined position is defined as the x direction. A direction perpendicular to both the x direction and the z direction is called the y direction. The secondary light L2 and the tertiary light L3 are assumed to travel in a three-dimensional space defined by an x-axis along the x-direction, a y-axis along the y-direction, and a z-axis along the z-direction.

  First, as shown in FIG. 4A, during the reference period P0 in which the secondary light L20 is incident on the reference reflection surface ML20, the secondary light L20 reflected by the reference reflection surface ML20 is a vector of the secondary light L20. And the vector of the normal line N0 of the reference reflecting surface ML20 and the vector based on For example, within the reference period P0, the vector of the tertiary light L30 changes along the x direction and the y direction in response to the rotation of the reference reflection surface ML20. On the other hand, within the reference period P0, the vector of the tertiary light L30 does not change in the z direction.

  On the other hand, as shown in FIG. 4B, the first reflecting surface ML21 rotates around the rotation axis AY in an angled state with respect to the rotation axis AY. Therefore, in the first period P1 in which the secondary light L21 is incident on the first reflection surface ML21, the vector of the tertiary light L31 not only changes along the x direction and the y direction, but also z Change along the direction. As a result, the tertiary light L31 is emitted in a direction different from the tertiary light L30 in the reference period P0 in the z direction.

  Further, as shown in FIG. 4C, the second reflecting surface ML22 rotates in a state having an angle different from that of the first reflecting surface ML21 with respect to the rotation axis AY. Therefore, even in the second period P2 in which the secondary light L22 is incident on the second reflecting surface ML22, the vector of the tertiary light L32 changes along the x direction, the y direction, and the z direction. Further, the tertiary light L32 is emitted in a direction different from the tertiary lights L30 and L31 in the z direction. In this embodiment, the tertiary light L32 is emitted in the z direction in the opposite direction to the tertiary light L31 with the tertiary light L30 as a reference.

  In this way, the reflective element 13 deflects the secondary light L2 in a directionally variable manner, and projects it as the tertiary light L3 toward various regions within the scanning region R0. The irradiation area of the tertiary light L3 becomes a scanning point or a distance measuring point.

  5A and 5B are diagrams showing an outline of a deflection mode of the primary light L1 by the deflection element 12. In the present embodiment, the deflection element 12 variably deflects the primary light L1 so as to change the z-direction component of the vector of the secondary light L2. In the following, the operation of the deflection element 12 during the first period P1 in which the secondary light L21 is incident on the first reflection surface ML21 will be described.

  First, as shown in FIG. 5A, the vector of the secondary light L21 is referred to as an incident vector Vi, the vector of the normal line N1 of the first reflecting surface ML21 is referred to as a normal vector Vn, and the vector of the tertiary light L31 is reflected. It is called a vector Vr. Further, the position of the first reflection surface ML21 in which the normal vector Vn has no y-direction component (the position having only x-direction and z-direction components) is used as a reference.

  Further, the angle formed by the incident vector Vi and the reflection vector Vr when viewed from the direction along the z direction is defined as the y-direction scanning angle θh. Further, the angle formed by the incident vector Vi and the x axis when viewed from the direction along the y direction is defined as the z direction incident angle θ. Further, the angle formed by the reflection vector Vr and the x axis when viewed from the direction along the y direction is defined as the z direction scanning angle θv. Further, the component in the z direction (component in the height direction) of the reflection vector Vr is referred to as the component Vr (z).

  Then, as shown in FIG. 5B, the first reflection surface ML21 has an angle β with the rotation axis AY, and the normal vector Vn of the first reflection surface ML21 is the rotation axis AY. Consider the case of rotating around by an angle γ.

  In the following, for simplicity of description, a case where the incident vector Vi has no y-direction component will be described. In this case, each of the x-direction component, the y-direction component, and the z-direction component of the incident vector Vi can be defined as a matrix shown in the following Expression (1).

また、法線ベクトルＶｎにおけるｘ方向の成分、ｙ方向の成分及びｚ方向の成分の各々は、以下の式（２）に示す行列として定義することができる。

Further, each of the x-direction component, the y-direction component, and the z-direction component of the normal vector Vn can be defined as a matrix shown in the following Expression (2).

このとき、反射ベクトルＶｒにおけるｘ方向の成分、ｙ方向の成分及びｚ方向の成分の各々は、角度θ、角度β及び角度γを用いて、以下の式（３）に示す行列式として表すことができる。

At this time, each of the x-direction component, the y-direction component, and the z-direction component in the reflection vector Vr is expressed as a determinant shown in the following formula (3) using the angle θ, the angle β, and the angle γ. You can

この式（３）を展開すると、反射ベクトルＶｒを以下の式（４）に示す行列として表すことができる。

When this expression (3) is expanded, the reflection vector Vr can be expressed as a matrix shown in the following expression (4).

式（４）は、第１の期間Ｐ１においては、反射ベクトルＶｒのｘ方向の成分、ｙ方向の成分及びｚ方向の成分の全てが角度θ、角度β及び角度γに応じて変化することを示している。換言すれば、回動軸ＡＹに対して角度β（β≠０）を持った反射面ＭＬ２である第１の反射面ＭＬ２１を回動軸ＡＹの周りに角度γで回動させた場合、入射ベクトルＶｉが固定されていた場合（角度θが一定の場合）でも、反射ベクトルＶｒのｚ方向の成分Ｖｒ（ｚ）が角度γに応じて変化することを示している。

Equation (4) indicates that in the first period P1, all of the x-direction component, the y-direction component, and the z-direction component of the reflection vector Vr change according to the angle θ, the angle β, and the angle γ. Shows. In other words, when the first reflecting surface ML21, which is the reflecting surface ML2 having an angle β (β ≠ 0) with respect to the rotation axis AY, is rotated about the rotation axis AY by the angle γ, the light is incident. It is shown that even when the vector Vi is fixed (when the angle θ is constant), the component Vr (z) in the z direction of the reflection vector Vr changes according to the angle γ.

  The change range of the y-direction component of the reflection vector Vr corresponds to the change range of the projection direction along the second direction D2 of the tertiary light L3 in the scanning plane R1. The change range of the z-direction component of the reflection vector Vr corresponds to the change range of the projection direction of the tertiary light L3 in the scanning plane R1 along the first direction D1.

  Therefore, in the first period P1, the projection direction of the tertiary light L31 is the first and second directions D1 and D2 in accordance with the rotation of the first reflecting surface ML21 (that is, the change of the angle γ). It will change along with both. This indicates that the trajectory of the tertiary light L31 on the scanning plane R1 is curved.

  Similarly, the directions of the tertiary light L32 reflected and projected by the second reflecting surface ML22 in the second period P2 are also the first and second directions in accordance with the rotation of the second reflected light L22. Would change along both directions D1 and D2. Further, the locus of the tertiary light L32 will be curved to a degree and in a direction different from the locus of the tertiary light L31.

  Therefore, although the trajectory of the tertiary light L3 extends linearly along the second direction D2 in the reference period P0, the trajectory of the tertiary light L3 in the other periods is curved. This is highly likely to result in omission of scanning or duplicate scanning in the scanning region R0.

  Therefore, in consideration of suppressing the omission of scanning and the suppression of overlapping scanning, it is preferable that the loci of the tertiary lights L31 and L32 extend linearly along the second direction D2. Specifically, for example, it is preferable that the projection direction of the tertiary light L31 does not change to the first direction D1 even when the first reflecting surface ML21 rotates. Further, for example, it is preferable that only the y-direction scanning angle θh is changed and the z-direction scanning angle θv is constant within the first period P1.

  On the other hand, in the present embodiment, the deflecting element 12 causes the secondary light L2 to enter the reflecting element 13 while changing the z-direction component of the secondary light L2. For example, the deflection element 12 changes the deflection direction of the primary light L1 and changes the incident angle θ of the secondary light L2 in the z direction so that the component Vr (z) of the reflection vector Vr in the z direction is constant. .

  More specifically, the z-direction component Vr (z) of the reflection vector Vr can be expressed by the following equation (5) using the z-direction scanning angle θv.

この式（５）をｚ方向入射角度θについて解くと、ｚ方向入射角度θは、以下の式（６）で表すことができる。

Solving this equation (5) for the z-direction incident angle θ, the z-direction incident angle θ can be expressed by the following equation (6).

従って、ｚ方向走査角度θｖを制御するには、ｚ方向走査角度θｖの所望の値（例えば固定値）を式（６）に代入した上で、角度β及びγを変数として式（６）によって導出された値をｚ方向入射角度θの制御値とすればよい。本実施例においては、偏向素子１２は、式（６）に従って１次光Ｌ１のｚ方向の成分を変化させるように１次光Ｌ１を偏向しつつ反射素子１３に入射させる。

Therefore, in order to control the z-direction scanning angle θv, a desired value (for example, a fixed value) of the z-direction scanning angle θv is substituted into the equation (6), and then the angles β and γ are used as variables according to the equation (6). The derived value may be used as the control value of the z-direction incident angle θ. In this embodiment, the deflecting element 12 deflects the primary light L1 so as to change the z-direction component of the primary light L1 according to the equation (6), and makes the primary light L1 incident on the reflecting element 13.

  FIG. 6A is a diagram showing simulation results of changes in the y-direction scanning angle θh and the z-direction scanning angle θv in the reference period P0 and the first and second periods P1 and P2, respectively. As shown in FIG. 6A, it can be seen that the z-direction scanning angle θv hardly changes during each period. This is because the deflection element 12 controls the incident angle θ in the z direction.

  FIG. 6B is a diagram schematically showing the projection points of the third-order lights L30 to L32 on the scanning plane R1 and their trajectories. In FIG. 6B, the locus TR0 of the tertiary light L30 from the reference reflecting surface ML20, the locus TR1 of the tertiary light L31 from the first reflecting surface ML31, and the locus of the tertiary light L32 from the second reflecting surface ML22. Each TR2 is shown by a broken line. In addition, the area of each light projecting point of each of the tertiary lights L30 to L32 is shown by a solid line.

  By adjusting the deflection direction of the primary light L1 by the deflecting element 12 as described above, as shown in FIG. 6B, the tertiary light L3 from all the reflecting surfaces ML20 to ML22 is directed along the second direction D2. The light can be projected so as to draw a linear trajectory. Therefore, it is possible to suppress the occurrence of the scan omission or the overlap scan region in the scan region R0.

  FIG. 7A is a diagram showing a simulation result of changes in the y-direction scanning angle θh and the z-direction scanning angle θv of the scanning region R0 by the distance measuring apparatus 100 according to the comparative example. Further, FIG. 7B is a diagram schematically showing the projection points of the scanning lights L30 to L32 and their loci in the distance measuring apparatus 100.

  The distance measuring device 100 has the same configuration as the distance measuring device 10 except that the deflecting element 12 is not included. That is, the range finder 100 is configured such that the secondary light L2 enters the reflecting element 13 in a state where the z-direction incident angle θ is fixed.

  As shown in FIG. 7A, in the distance measuring device 100, the third-order light L30 from the reference reflecting surface ML20 is projected so as to draw the same trajectory TR0 as the distance measuring device 10. On the other hand, each of the tertiary lights L31 and L32 from the first and second reflecting surfaces ML21 and ML22 is projected in each period P2 and P3 while changing the z-direction scanning angle θv according to the equation (5). It

  Therefore, as shown in FIG. 7B, the trajectories TR10 and TR20 of the tertiary lights L31 and L32 are near the end of the scanning surface R1 in the second direction D2, and the tertiary light L30 in the first direction D1. Approach the trajectory of. Therefore, in the vicinity of the end of the scanning surface R1 in the second direction D2, an unscanned region and a region in which overlapping scanning is performed are formed, and the scanning accuracy is greatly reduced. Therefore, it may be necessary to reduce the scanning region R0 in consideration of obtaining accurate scanning information.

  On the other hand, in this embodiment, the deflecting element 12 deflects the primary light L1 so as to change the z-direction component of the primary light L1 and makes the primary light L1 incident on the reflecting element 13. It is possible to project all the secondary light L2 entering each of the reflecting surfaces ML20 to ML22 toward a desired area. Therefore, it is possible to project the tertiary light L3 toward the entire scanning region R0 without unevenness and without waste. Therefore, scanning leakage and overlapping scanning are suppressed over a wide range of the projection area of the tertiary light L3, and accurate scan information can be obtained over a wide range.

  As described above, in the present embodiment, the deflection element 12 determines the z-direction incident angle θ of the incident vector Vi of the secondary lights L21 and L22 incident on the first and second reflecting surfaces ML21 and ML22 of the reflecting element 13. , According to the rotation of the reflection element 13. Therefore, the reflection vector Vr of the secondary lights L21 and L22, that is, the projection direction of the tertiary lights L31 and L32 can be adjusted to be a desired direction. Therefore, light can be projected in a desired direction over a wide range.

  In the present embodiment, the case where the reflecting element 13 has three reflecting surfaces ML20 to ML22 and each of the reflecting surfaces ML20 is a polygon mirror having different angles with respect to the rotation axis AY has been described. However, the configuration of the reflective element 13 is not limited to this.

  The reflective element 13 may have at least one reflective surface. For example, the reflective element 13 may be a galvano mirror or a MEMS mirror having only the first reflective surface ML21. The reflecting element 13 may be rotated around the rotation axis AY to reflect the primary light L1 that has passed through the deflecting element 12 and to have a reflecting surface ML2 having an angle with the rotation axis AY.

  Further, in the present embodiment, the case where the reflecting surface ML2 is a flat surface has been described. However, a part of the reflecting surface ML2 may have an uneven structure or may be curved. The reflective element 12 may have the reflective surface ML that has an angle with respect to the rotation axis AY in at least the region where the secondary light L2 is incident.

  Further, in the present embodiment, the case where the deflection element 12 is composed of the MEMS mirror having the swing mirror ML1 that swings around the swing axis AX in the direction perpendicular to the rotation axis AY of the reflective element 13 has been described. However, the configuration of the deflection element 12 is not limited to this.

  The deflecting element 12 may be configured to deflect the primary light L1 in a variable direction. For example, the deflection element 12 may have a movable lens or may have a liquid crystal lens. The variable range of the deflection direction of the primary light L1 in the deflection element 12 is not limited to the z direction. For example, the deflection element 12 may be configured to variably deflect the primary light L1 along various directions including the z direction.

  Further, in the present embodiment, the deflection element 12 changes the deflection direction of the primary light L1 according to the equation (6) in accordance with the inclination angle β and the rotation angle γ of the reflecting surface ML2 with respect to the rotation axis AY. The case has been described above. For example, the case where the deflecting element 12 controls the z-direction incident angle θ with the z-direction scanning angle θv during each period as a fixed value has been described. However, the deflection mode of the primary light L1 by the deflection element 12 is not limited to this.

  For example, the deflection element 12 is not limited to the case of complying with Expression (6), and is configured to change the deflection direction of the primary light L1 according to the rotation of the reflection surface ML2 (according to the change of the angle γ). If you have. In this case, for example, the deflection element 12 preferably changes the deflection direction of the primary light L1 according to the change of the normal vector Vn of the reflection surface ML2.

  Further, for example, the deflection element 12 deflects the primary light L1 so as to change the component of the primary light L1 along the z direction, that is, the component of the primary light L1 along the axial direction of the rotation axis AY. Preferably. Further, for example, the deflection element 12 preferably changes the deflection direction of the primary light L1 according to the angle formed by the reflection surface ML2 and the rotation axis AY, that is, the angle β.

  However, the deflection mode of the primary light L1 by these deflection elements 12 is merely an example. That is, the deflecting element 12 that deflects the primary light L1 in a variable direction may be provided between the light source 11 and the reflecting element 13. As a result, by operating the deflection element 12, it is possible to project light in a desired direction over a wide range. Then, stable and accurate distance measurement can be performed over a wide range.

  Further, in the present embodiment, the case where the light source 11 emits the primary light L1 in the shape of a point beam has been described. However, the configuration of the light source 11 is not limited to this. For example, the light source 11 may be configured to emit the primary light L1 having a linear beam shape. Further, the light source 11 may have a plurality of emission ports that each emit a laser beam, and may emit the entire plurality of laser beams as the primary light L1.

  Further, in this embodiment, the case where the operations of the light source 11, the deflection element 12, and the reflection element 13 are controlled by the control unit 20 has been described. However, each of the light source 11, the deflection element 12, and the reflection element 13 may have its own control program and be configured to operate in cooperation with each other. That is, the light source control unit 21, the deflection element control unit 22, and the reflection element control unit 23 may not be provided.

  As described above, in the present embodiment, the distance measuring device 10 includes the light source 11 that emits light (primary light L1), the deflection element 12 that deflects the light in a directionally variable direction, and the rotation axis AY. The reflection element 13 that is rotated to reflect the light that has passed through the deflection element 12 and that has the reflection surface ML2 that has an angle with the rotation axis AY, and is projected through the reflection element 13 and reflected by the object OB. A light receiving element 15 that receives reflected light (fourth light L4) that is light and a distance measuring unit 24 that measures the distance to the object OB based on the light reception result of the reflected light by the light receiving element 15 are included. Therefore, it is possible to provide the distance measuring device 10 capable of performing highly accurate scanning and distance measurement over a wide range by projecting light in a desired direction over a wide range.

  The light reception result of the fourth-order light L4 from the light receiving element 15 in the distance measuring device 10 is useful information for applications other than distance measurement, for example, simple detection applications. Therefore, the distance measuring device 10 may not have the distance measuring unit 24. In this case, the distance measuring device 10 functions as a scanning device.

  Further, the distance measuring device 10 may not have the light receiving element 15 in addition to the distance measuring unit 24. The third-order light L3 projected through the reflection element 13 can be sufficiently used for light projection applications such as illumination. That is, when the distance measuring device 10 does not have the light receiving element 15 and the distance measuring unit 24, the light source 11, the deflecting element 12, and the reflecting element 13 function as a light projecting device.

  As described above, the light projecting apparatus according to the present embodiment is configured to rotate the light source 11 that emits light (primary light L1), the deflection element 12 that deflects the light in a variable direction, and the rotation axis AY. Then, the reflection element 13 that has a reflection surface ML2 that reflects the light that has passed through the deflection element 12 and that has an angle with the rotation axis AY. Therefore, it is possible to provide the light projecting device which has the reflecting element 13 having the rotating reflecting surface ML2 and is capable of projecting light in a desired direction over a wide range.

  FIG. 8 is a diagram illustrating the overall configuration of the distance measuring device 30 according to the second embodiment. The distance measuring device 30 has the same configuration as the distance measuring device 10 except for the configurations of the deflection element 31, the light receiving element 32, and the control unit 40. In the distance measuring device 30, the deflection element 31 changes the deflection direction of the primary light L1 so that the secondary light L2 reflected by the reflecting surface ML is projected along a plurality of loci apart from each other. Is configured. The deflecting element 31 has, for example, a configuration similar to that of the deflecting element 12, and is configured so that the deflection mode is changed by the drive signal.

  Further, the light receiving element 32 is configured to receive each of the quaternary light L4 corresponding to the tertiary light L3 projected along the plurality of loci. In addition, the control unit 40 controls the deflection element control unit 41 that adjusts the drive signal supplied to the deflection element 31, and the objects OB at a plurality of focus detection points based on the plurality of light reception results obtained from the light receiving element 32. And a distance measuring unit 42 that collectively performs distance measurement.

  In the present embodiment as well, the distance measuring device 30 has the reflecting element 13 that rotates about the rotation axis AY and that has a plurality of reflection surfaces ML20 to ML22 that have different angles β with the rotation axis AY. .

  In the present embodiment, the deflection element 31 controls the z-direction incident angle θ in the above equation (6) according to the z-direction scanning angle θv set as a discrete value. More specifically, in the deflecting element 31, for example, the secondary light L2 incident on the first reflecting surface ML21 has a z-direction scanning angle θv (for example, the first, second and second) which are discrete fixed values different from each other. The deflection direction of the primary light L1 is changed so that it is reflected at the third z-direction scanning angle).

  In other words, in the deflecting element 31, for example, of the reflecting surfaces ML20 to ML22, the incident period of the secondary light L2 on the first reflecting surface ML21 of the first reflecting surface ML21 on which the secondary light L2 is incident. The deflection direction of the primary light L1 is changed so that the component Vr (z) in the z direction of the secondary light L2 (third light L3) reflected by the first reflecting surface ML21 has a plurality of discrete values. Let

  That is, in the present embodiment, the deflection element 31 not only adjusts (corrects) the locus of the tertiary light L3, but also increases the locus of the tertiary light L3 to move the scanning region R0 in the first direction D1. The primary light L1 is deflected so as to expand. Therefore, in the distance measuring device 30, both the deflection element 31 and the reflection element 13 function as scanning elements.

  FIG. 9 is a diagram schematically showing a projection point of the tertiary light L3 on the scanning plane R1 by the distance measuring device 30 and its locus. In the present embodiment, the deflection element 31 controls the z-direction incident angle θ based on the z-direction scanning angle θv of three discrete values in each of the three reflecting surfaces ML20 to ML22.

  Therefore, the tertiary light L3 reflected by the reference reflection surface ML20 is projected so as to draw three trajectories TR01 to TR03 that are separated from each other along the first direction D1 and extend along the second direction D2. The third-order lights L301 to L303 are generated.

  Similarly, the tertiary light L3 reflected by the first reflecting surface ML21 draws three trajectories TR11 to TR13 that are separated from each other along the first direction D1 and extend along the second direction D2. It becomes the projected tertiary light L311 to L313.

  Further, the tertiary light L3 reflected by the second reflecting surface ML22 is projected so as to draw three trajectories TR21 to TR23 which are separated from each other along the first direction D1 and extend along the second direction D2. It becomes the tertiary light L321 to L323 that are emitted.

  Thereby, the three reflecting surfaces ML20 to ML22 can be used to project the tertiary light L3 along different trajectories in nine steps along the first direction D1. Further, each of the third-order lights L3 is projected at an arrangement interval with no unevenness and no waste in the entire area. Therefore, by projecting light in a desired direction over a wide range, it becomes possible to perform highly accurate distance measurement.

  FIG. 10 is a diagram showing an example of control of the deflection mode of the primary light L1 by the deflection element 31. For example, the deflection element 31 performs the deflection operation of the primary light L1 so as to change the projection direction of the tertiary light L3 during the period in which the secondary light L2 is incident on each of the reflection surfaces ML20 to ML22. May be. In this case, as shown in FIG. 10, immediately after the end of the reference period P0, each of the tertiary lights L311 to L313 corresponds to the first, second, and third z-direction scanning angles θv (ML20). The light is projected so as to draw loci TR01, TR02, and TR03.

  Then, after the end of the first and second periods P1 and P2, the first, second and third z-direction scanning angles θv (ML20), the first, second and third z-direction scanning angles θv ( ML21) and the projection of the third-order light L3 along the trajectories TR01 to TR03, TR11 to TR13, and TR21 to TR23 corresponding to all of the first, second, and third z-direction scanning angles θv (ML22) are completed. . In this case, the tertiary light L3 can be projected over a wide range in a short time.

  FIG. 11 is a diagram showing another control example of the deflection mode of the primary light L1 by the deflection element 31. For example, the deflection element 31 does not change the z-direction scanning angle θv during the period in which the secondary light L2 is incident on each of the reflecting surfaces ML20 to ML22, but changes the z-direction scanning angle θv for each period. The deflection operation of the primary light L1 may be performed.

  In this case, as shown in FIG. 11, for example, in the first period P11 in which the secondary light L2 is incident on the reference reflection surface ML20, 1 corresponding to the first z-direction scanning angle θv (ML20). The tertiary light L301 is projected along one trajectory TR01. Similarly, in the second period P21 in which the secondary light L2 is incident on the first reflecting surface ML21, the tertiary light L311 is along the one trajectory TR11 of the first z-direction scanning angle θv (ML21). Is projected. Further, within the third period P31 in which the secondary light L2 is incident on the second reflecting surface ML22, the tertiary light L321 is generated along the one trajectory TR31 of the first z-direction scanning angle θv (ML22). It is projected.

  Then, within the fourth period P12 in which the secondary light L2 is incident on the reference reflection surface ML20 after the first period P11, one trajectory corresponding to the second z-direction scanning angle θv (ML20). The third light L302 is projected along TR02. Similarly, in the fifth and sixth periods P22 and P32 in which the secondary light L2 is incident on the first and second reflecting surfaces ML21 and ML22 after the second and third periods P21 and P31, Third-order lights L312 and L322 are projected along trajectories TR22 and TR32 corresponding to the second z-direction scanning angles θv (ML21) and θv (ML22), respectively.

  Similarly, in the seventh, eighth, and ninth periods P13, P23, and P33, the loci TR03 corresponding to the third z-direction scanning angles θv (ML20), θv (ML21), and θv (ML22), respectively. Tertiary lights L303, L313, and L323 are projected along TR13 and TR23.

  In this way, the deflection element 31 changes the deflection direction of the primary light L1 along the z direction so that the tertiary light L3 is projected along different trajectories over the nine periods. Good. As a result, the control of the deflection element 31 is facilitated, and the tertiary light L3 can be projected stably in a desired direction.

  FIG. 12 is a plan view showing a configuration example of the light receiving surface 32A of the light receiving element 32. As shown in FIG. 12, the light receiving element 32 has a light receiving surface 32A composed of three light receiving segments SG1, SG2 and SG3 arranged along the first direction D1. The three light receiving segments SG1 to SG3 perform the light receiving operation of the fourth-order light L4 independently of each other. For example, the light receiving element 32 is a line sensor having a light receiving surface 32A extending along the first direction D1.

  In the present embodiment, the light receiving segment SG1 receives one of the tertiary lights L3 from each of the reflection surfaces ML20 to ML22, for example, the quaternary light L4 corresponding to the tertiary lights L303, L313 and L323. Are configured and arranged in. Similarly, the light receiving segment SG2 is configured and arranged to receive the fourth order light L4 corresponding to the third order lights L301, L311 and L321. Further, the light receiving segment SG3 is configured and arranged so as to receive the fourth order light L4 corresponding to the third order lights L302, L312 and L322.

  The light receiving element 32 receives the quaternary light L4 by the plurality of light receiving segments SG1 to SG3, and thus individually receives the quaternary light L4 corresponding to all the tertiary light L301 to L303, L311 to L313, and L321 to L323. be able to. Therefore, for example, even when the third-order light L3 is projected in the manner as shown in FIG. 10, the fourth-order lights L4 corresponding to the respective third-order lights L3 projected in the same period are collectively and individually. Can receive light. Further, the distance measuring unit 24 can perform the distance measuring operation collectively, for example, using these light reception results.

  Note that, also in the present embodiment, the mode of deflection of the secondary light L2 by the reflective element 13 is merely an example. The reflective element 13 can reflect the secondary light L2 in various modes as described in the first embodiment. Further, the light receiving element 32 is not limited to having a plurality of light receiving segments SG1 to SG3, and may be configured to receive the quaternary light L4.

  As described above, in the present embodiment, the distance measuring device 30 includes the light source 11, the deflection element 31 that deflects the primary light L1 emitted from the light source 11 in a directionally variable manner, and the angle β with respect to the rotation axis AY. A reflection element 13 having a plurality of different reflection surfaces ML20 to ML22 and reflecting the primary light L1 having passed through the deflection element 31 by each of the plurality of reflection surfaces ML20 to ML22, and receiving the reflection light L4 from the object OB. The light receiving element 32 having a plurality of light receiving segments SG1 to SG3, and the distance measuring unit 42 for measuring the distance to the object OB based on the light receiving result of the reflected light L4 by the light receiving element 32. Therefore, by changing the direction of the secondary light L2 to be incident on each of the plurality of reflecting surfaces ML20 to ML22 by the deflecting element 31, the light is projected in a desired direction over a wide range, so that the light is increased over a wide range. It is possible to provide the distance measuring device 30 capable of performing accurate distance measurement.

  Further, in the present embodiment, the distance measuring device 30 may not include the light receiving element 32 and the distance measuring unit 42. In this case, for example, the light source 11, the deflection element 31, and the reflection element 13 function as a light projecting device.

  Therefore, for example, the light projecting device according to the present embodiment is configured so that the light source 11 that emits light (primary light L1), the deflection element 31 that deflects the light in a variable direction, and the rotation about the rotation axis AY. The reflective element 13 has a plurality of reflective surfaces ML20 to ML22 having different angles β with respect to the rotation axis AY. Therefore, it is possible to provide a light projecting device capable of projecting light in a desired direction over a wide range.

10, 30 Distance measuring device 11 Light source 12, 31 Deflecting element 13 Reflecting element 15, 32 Light receiving element 24, 42 Distance measuring section

Claims (7)

A light source that emits light,
A deflection element for deflecting the light in a variable direction,
And a reflecting element that rotates around a rotation axis, reflects the light that has passed through the deflection element, and has a reflection surface that forms an angle with the rotation axis.   The light projecting device according to claim 1, wherein the deflection element changes a deflection direction of the light according to rotation of the reflection surface of the reflection element.   The deflection element changes the deflection direction of the light according to a change in a normal vector of the reflection surface during a period in which the light is incident on the reflection surface. The floodlighting device described.   4. The light projecting device according to claim 1, wherein the deflecting element deflects the light so as to change a component of the light along the axial direction of the rotating shaft. apparatus.   The light projecting device according to any one of claims 1 to 4, wherein the deflecting element changes a deflecting direction of the light according to an angle formed by the rotating shaft and the reflecting surface.   The deflection element is configured so that the component of the light reflected by the reflecting surface becomes constant along the axial direction of the rotation axis within a period in which the light is incident on the reflecting surface. The light projecting device according to any one of claims 1 to 5, wherein the deflection direction is changed. A light projecting device according to any one of claims 1 to 6,
A light receiving element that receives the reflected light that is the light projected through the reflecting element and reflected by an object,
A distance measuring unit that measures a distance to the object based on a light reception result of the reflected light by the light receiving element.

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