Optical scanning device, object detection device, sensing device and moving body

Abstract

To provide an optical scanner that can achieve size reduction and wide angle, an object detection device, a sensing device, and a movable body.SOLUTION: An optical scanner has a light source unit that emits a light beam, and a first optical deflector that has a first optical deflection surface deflecting and scanning the light beam. The first optical deflector is freely rotatable with respect to the light beam centered on a rotation axis located outside the first optical deflector. The first optical deflector is freely rotatable at a rotation position where the first optical deflection surface and the light beam become parallel to each other. At the rotation position where the first optical deflection surface and the light beam become parallel to each other, they do not interfere with each other.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to an optical scanning device, an object detection device, a sensing device, and a moving body. [Background technology]

[0002] For example, in the operation of moving objects such as vehicles, ships, and aircraft, technologies are used to detect the position information of objects over a wide angular range. One such sensing technology is LiDAR (Light Detection and Ranging). LiDAR is a remote sensing method that uses light, and uses the TOF (Time of Flight) method, which measures the distance to an object from the time it takes for a laser light emitted from a laser light source to be reflected by the object and return to a detector. There are means for scanning the laser light over a wide angle using a scanning means such as a MEMS (Micro Electro Mechanical Systems) mirror or a polygon mirror, which allows the position information of an object to be obtained over a wide angular range.

[0003] Patent Document 1 describes a LIDAR system having at least one processor. This LIDAR system causes light emitted from a plurality of light sources to enter one deflector. The LIDAR system (processor) controls at least one light source to vary the light flux in scanning the field of view using light from the at least one light source. The processor also controls at least one light deflector to deflect the light from the at least one light source to scan the field of view. The processor also uses a first detected reflection associated with the scanning of a first portion of the field of view to determine the presence of a first object at a first distance in the first portion. The processor also determines the absence of an object at the first distance in a second portion of the field of view. The processor also changes light source parameters such that more light is projected toward the second portion of the field of view than is projected toward the first portion of the field of view. The processor also uses a second detected reflection in the second portion of the field of view to determine the presence of a second object at a second distance greater than the first distance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2019-535014 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional distance measuring devices including that of Patent Document 1, it was difficult to simultaneously realize a system that is both compact and can measure distances at a wide angle. For example, an optical distance measuring system such as Velodyne uses a method of rotating the entire system 360 degrees to measure distances at a wide angle of 360 degrees, but this method results in an increase in size due to the incorporation of mechanisms such as motors. When realizing a wide angle using multiple light sources like Innoviz, the system becomes large due to the arrangement of multiple light sources and the layout of the optical path.

[0006] The present invention has been made based on the above-mentioned awareness, and has an object to provide an optical scanning device, an object detection device, a sensing device, and a moving body that can be made smaller and have a wider angle. [Means for solving the problem]

[0007] The optical scanning device of this embodiment includes a light source unit that emits a light beam, and a first optical deflector having a first optical deflection surface that deflects and scans the light beam, the first optical deflection surface is provided on a side of an incidence surface of the first optical deflector on which the light beam is incident, and an external rotation axis located outside the first optical deflector is set to face the first optical deflection surface and be spaced apart from the first optical deflection surface; The first optical deflector includes: The external pivot shaft The first optical deflector is rotatable about a center with respect to the light beam, and the first optical deflector is rotatable to a rotation position where the first optical deflection surface and the light beam are parallel to each other, and at the rotation position where the first optical deflection surface and the light beam are parallel to each other, the first light deflection surface and the light beam are spaced apart, The first light deflection surface and the light beam do not interfere with each other. Effect of the Invention

[0008] According to the present invention, it is possible to provide an optical scanning device, an object detection device, a sensing device, and a moving body that can be made smaller and have a wider angle. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing an example of a configuration of an optical scanning device according to an embodiment of the present invention; [Diagram 2] 5 is a diagram showing various parameters in the optical scanning device according to the present embodiment. FIG. [Diagram 3] 1 is a diagram illustrating an example of a configuration of an object detection device according to an embodiment of the present invention. [Figure 4] FIG. 1 is a functional block diagram of an object detection device that realizes distance measurement using a TOF method. [Diagram 5] FIG. 1 is a diagram illustrating an example of a configuration of a sensing device according to an embodiment of the present invention. [Figure 6] FIG. 1 is a diagram showing an automobile as an example of a moving body according to an embodiment of the present invention. [Figure 7] FIG. 1 is a diagram illustrating an example of an optical deflector according to a comparative example. [Figure 8]FIG. 8 is a diagram showing the scanning angle range when the optical deflector in FIG. 7 rotates in the range of 0 degrees to 360 degrees. [Figure 9] 10 is a diagram showing the relationship between the deflector angle and the scanning angle when the optical deflector rotates in the range of 0 deg to 360 deg. [Figure 10] 5A and 5B are diagrams illustrating an example of a rotational position of a first optical deflector with respect to a light beam. [Figure 11] 13A and 13B are diagrams illustrating other examples of rotation positions of the first optical deflector with respect to the light beam. [Figure 12] FIG. 12 is a diagram showing the scanning angle range when the first optical deflector in FIG. 10 and FIG. 11 rotates in the range of 0 deg to 360 deg.; [Figure 13] 4 is a diagram for explaining an optimum installation position of the first optical deflector with respect to a light beam. FIG. [Figure 14] FIG. 13 is a diagram showing a spatial profile of a light beam normalized with respect to the Z-axis direction. [Figure 15] FIG. 13 is a diagram showing an example in which a second optical deflector is provided in addition to a first optical deflector. [Figure 16] 13 is a diagram showing an example of a preferable arrangement position of a light source section when only a first optical deflector is provided. FIG. [Figure 17] 13 is a diagram showing an example of a preferable arrangement position of a second optical deflector when a first optical deflector and a second optical deflector are provided. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an example of an optical scanning device, an object detection device, a sensing device, and a moving body according to the present embodiment will be described. The present embodiment can be applied to, for example, a sensing device mounted on a moving body such as a vehicle, a ship, or an aircraft, a robot used in a factory or a warehouse, or a variety of drones. The present embodiment can also be applied to an optical projection device such as a three-dimensional measuring device. In addition, the present embodiment can be applied to an optical scanning device, an object detection device, a sensing device, and a moving body in any current or future technical field.

[0011] In the following description, the X-axis, Y-axis, and Z-axis directions are based on the directions of the arrows shown in the drawings, and form a three-dimensional space in which the X-axis, Y-axis, and Z-axis directions are mutually orthogonal.

[0012] FIG. 1 is a diagram showing an example of the configuration of an optical scanning device 1 according to this embodiment.

[0013] The optical scanning device 1 has a light source unit 10, a light projecting optical element 20, and an optical deflector (scanning mirror) 30. Although details will be described later, in this embodiment, a first optical deflector 310 and a second optical deflector 320 (at least the first optical deflector 310) are provided as the optical deflector 30, and the optical deflection surface of the optical deflector, the rotation axis, the arrangement of the light beam incident on the optical deflector, and the like can be devised to increase the optical deflection angle. However, in FIG. 1, the optical deflector 30 having a general configuration and function is depicted for explanation.

[0014] The light source unit 10 emits a light beam diverging at a predetermined angle in the X-axis direction. The light source unit 10 can be configured, for example, from a semiconductor laser (LD: Laser Diode). Alternatively, the light source unit 10 can be configured from a surface emitting laser (VCSEL (Vertical Cavity Surface Emitting LASER)) or an LED (Light Emitting Diode), etc. In this way, there is a degree of freedom in how the light source unit 10 is configured, and various design modifications (substitutions) are possible.

[0015] The light projecting optical element 20 shapes the light beam from the light source unit 10. Specifically, the light projecting optical element 20 shapes the light beam incident thereon while diverging at a predetermined angle into a substantially parallel beam. The light projecting optical element 20 can be composed of, for example, a coaxial aspheric lens that couples the light beam, which is a diverging light, and shapes it into a substantially parallel beam. Note that, although the light projecting optical element 20 is depicted as a single lens in FIG. 1, the light projecting optical element 20 may be composed of a plurality of lenses.

[0016] The optical deflector 30 has an optical deflection surface 31 that deflects and scans the light beam from the light projecting optical element 20. Specifically, the optical deflector 30 deflects and scans the light beam emitted in the X-axis direction by the light source unit 10 and the light projecting optical element 20 in a predetermined scanning range of the XZ plane including the X-axis direction and the Z-axis direction. The scanning range by the optical deflector 30 is set, for example, by changing the angle of the optical deflection surface 31 by vibration or rotation (rotation, swing). In FIG. 1, the reference position of the optical deflector 30 (optical deflection surface 31) in the above-mentioned scanning range is drawn by a solid line, and the scanning position of the optical deflector 30 (optical deflection surface 31) (for example, a middle position between the reference position and both scanning end positions) is drawn by a dashed line.

[0017] FIG. 2 is a diagram showing various parameters in the optical scanning device 1 according to the present embodiment.

[0018] In Fig. 2, θ indicates a half angle of the predetermined angle (divergence angle) of the light beam from the light source unit 10. The predetermined angle (divergence angle) of the light beam from the light source unit 10 and its half angle θ are expressed as 1 / e of the peak intensity in the profile of the light beam from the light source unit 10. 2 The angle at which the intensity is expressed as 1 / e 2 When the intensity of the light beam from the light source unit 10 has a Gaussian angular distribution, θ or 2θ contains 95% of the total amount of light output by the light source unit 10. This makes it possible to suppress loss of the amount of light from the light source unit 10 and to reduce the size of the light projecting optical element 20.

[0019] In FIG. 2, a indicates the half width of the size of the light deflection surface 31 of the light deflector 30. Here, the light deflection surface 31 of the light deflector 30 can be, for example, a square, a rectangle, a circle, or an ellipse. When the light deflection surface 31 of the light deflector 30 is a square, the size of the light deflection surface 31 is the length of one side of the square, and half of that length is the half width a of the size of the light deflection surface 31. When the light deflection surface 31 of the light deflector 30 is a rectangle, the size of the light deflection surface 31 is the length of the long side or short side of the rectangle, and half of that length is the half width a of the size of the light deflection surface 31. When the light deflection surface 31 of the light deflector 30 is a circle, the size of the light deflection surface 31 is the diameter of the circle, and half of that length is the half width a of the size of the light deflection surface 31. When the light deflection surface 31 of the light deflector 30 is elliptical, the size of the light deflection surface 31 is the major axis or minor axis of the ellipse, and half the length of the major axis or minor axis is the half width a of the size of the light deflection surface 31 .

[0020] 2, f indicates the focal length of the light-projecting optical element 20. As shown in Fig. 2, the light source unit 10 is disposed so that the distance between the light-emitting point of the light source unit 10 and the principal plane of the light-projecting optical element 20 is equal to the focal length f of the light-projecting optical element 20. As a result, the light beam from the light source unit 10 is shaped by the light-projecting optical element 20 to become a substantially parallel beam.

[0021] 2, α indicates the angle of incidence of the light beam with respect to the light deflection surface 31 of the light deflector 30. In other words, α is the angle between the normal to the light deflection surface 31 of the light deflector 30 and the central ray (optical axis) of the light beam before it is incident on the light deflection surface 31 of the light deflector 30.

[0022] In FIG. 2, the light flux diameter h of the light beam shaped by the light projecting optical element 20 is expressed by the following formula. h=2ftanθ

[0023] The above light beam is incident on the light deflection surface 31 of the light deflector 30 at an incident angle α. At this time, the beam diameter of the light beam on the light deflection surface 31 of the light deflector 30 is expressed by the following formula. h / cosα=2ftanθ / cosα

[0024] 3 is a diagram showing an example of the configuration of an object detection device 2 according to this embodiment. The object detection device 2 has a light receiving optical system 40, a light receiving optical element 50, and a drive substrate 60 in addition to the light source unit 10, the light projecting optical element 20, and the optical deflector 30 of the optical scanning device 1.

[0025] When an object is present within the area where the light beam is scanned by the optical deflector 30, the light beam is reflected or scattered by the object. The light beam reflected or scattered by the object passes through the light receiving optical system 40 and is received by the light receiving optical element 50. The light receiving optical element 50 functions as an "object detection unit" that detects the light beam from the light source unit 10 reflected or scattered by an object present in the detection area and determines the object detection timing. Information on the object can be detected based on the light emission timing of the light source unit 10 and the object detection timing by the light receiving optical element (object detection unit) 50. Alternatively, the scanned light beam can detect light reflected or scattered by the object, and information on the object can be detected based on the light emission information of the light beam emitted from the light source unit 10 and the light reception information of the detected light. The drive board 60 drives and controls the light source unit 10 and the light receiving optical element 50.

[0026] The light receiving optical system 40 can adopt one of various configurations that can collect light to the light receiving optical element 50, such as a lens system, a mirror system, and other configurations (the configuration of the light receiving optical system 40 is flexible and is not limited to a specific configuration).

[0027] The light receiving optical element 50 can be composed of, for example, a PD (Photo Diode), an APD (Avalanche Photo Diode), a SPAD (Single Photon Avalanche Diode) which is a Geiger mode APD, or a CMOS imaging element (TOF sensor) having a TOF (Time of Flight) calculation function for each pixel.

[0028] Fig. 4 is a functional block diagram of an object detection device 2 that realizes distance measurement using the TOF method. As shown in Fig. 4, a waveform processing circuit 70, a time measurement circuit 80, a measurement control unit 90, and a light source drive circuit 100 are provided as components that connect the light source unit 10 and the light receiving optical element 50. The object detection device 2 also has an image acquisition unit 110, an image processing unit 120, and an information combination unit 130.

[0029] The waveform processing circuit 70 performs a predetermined waveform processing on the light beam received by the light receiving optical element 50 and outputs a detection signal. The time measurement circuit 80 measures the time from the light emission timing of the light source unit 10 to the object detection timing of the light receiving optical element 50 based on the detection signal from the waveform processing circuit 70, and outputs the time measurement result. The measurement control unit 90 detects information of an object present in the detection area based on the time measurement result from the light emission timing of the light source unit 10 to the object detection timing of the light receiving optical element 50 input from the time measurement circuit 80 (the light emission timing of the light source unit 10 and the object detection timing of the light receiving optical element 50). In addition, the measurement control unit 90 outputs a light source drive signal based on the information of the detected object. The light source drive circuit 100 controls the light emission of the light source unit 10 based on the light source drive signal from the measurement control unit 90.

[0030] The time from when light source unit 10 emits a pulsed light until the light beam returning via the object reaches light-receiving optical element 50 is measured via waveform processing circuit 70 and time measurement circuit 80, and this value is multiplied by the speed of light to calculate the round-trip distance that the light travels from object detection device 2 to the object. The light projecting system and light receiving system are at almost the same distance from the object, and the distance from light source unit 10 to the object and the distance from the object to light-receiving optical element 50 can be considered to be approximately the same. Taking advantage of this fact, half the found round-trip distance is calculated as the distance from object detection device 2 to the object.

[0031] The image acquisition unit 110 is composed of, for example, an imaging element (CCD: Charge Coupled Device), and acquires an image of an object present in the detection area. The image processing unit 120 processes the image of the object acquired by the image acquisition unit 110 to generate image information. The information combination unit 130 combines the image information from the image processing unit 120 and the object information from the measurement control unit 90. This combined information is, for example, a combination of an image of an object to be measured present in the detection area and distance information (distance measurement information) of the object to be measured, and can be used by being displayed on a display (not shown) or stored in a memory (not shown).

[0032] 5 is a diagram showing an example of the configuration of a sensing device 3 according to this embodiment. The sensing device 3 includes the above-mentioned object detection device 2 and a monitoring control device 4. The object detection device 2 and the monitoring control device 4 are electrically connected to each other.

[0033] Fig. 6 is a diagram showing an automobile 5 as a moving body according to this embodiment. A sensing device 3 is mounted (built-in) on the automobile (moving body) 5. The sensing device 3 is attached, for example, near the bumper or near the rearview mirror of the automobile 5. Note that, although Fig. 5 shows the monitoring and control device 4 as being provided inside the sensing device 3, it is also possible to provide the monitoring and control device 4 in the automobile 5 separately from the sensing device 3.

[0034] The monitoring control device 4 acquires information including at least one of the presence or absence of an object, the moving direction of the object, and the moving speed of the object based on the output of the object detection device 2. Furthermore, the monitoring control device 4 performs processes such as determining the shape and size of the object, calculating the position information of the object, calculating the movement information, and recognizing the type of object based on the output of the object detection device 2. Then, the monitoring control device 4 controls the movement of the moving body (here, the traveling of the automobile 5) based on at least one of the position information and the movement information of the object. For example, when it is determined that there is an obstacle ahead of the automobile 5, it applies automatic braking using automatic driving technology, and issues commands to sound an alarm, turn the steering wheel, and apply the brakes.

[0035] 7A and 7B are diagrams showing an example of an optical deflector 30' according to a comparative example. The optical deflector 30' has an optical deflection surface 31' that deflects and scans the optical beam from a light source unit and a light projecting optical element, both of which are not shown. In FIGS. 7A and 7B, the rotation axis (rotation axis, oscillation axis) of the optical deflector 30' exists inside (at the center) of the optical deflector 30' and extends in the Y-axis direction, and the optical deflector 30' is freely rotatable around the Y-axis around the rotation axis. FIG. 7A illustrates a case where the rotation axis is set such that the distance between the optical beam and the optical deflection surface 31' is 0 or more when the optical deflection surface 31' of the optical deflector 30' is parallel to the XY plane, and FIG. 7B illustrates a case where the rotation axis is set such that the distance between the optical beam and the optical deflection surface 31' is 0 or less when the optical deflection surface 31' of the optical deflector 30' is parallel to the XY plane.

[0036] The rotation position of the optical deflector 30' depicted in Figures 7A and 7B is a position where the optical deflection surface 31' is rotated 15 degrees counterclockwise around the Y axis from the 0 degree reference position (the position where the optical deflection surface 31' is parallel to the light beam). In this case, it can be seen that the light beam is deflected and scanned in both Figures 7A and 7B.

[0037] However, an optical deflector intended for wide-angle scanning is required to scan light widely over a rotation (rotation, swing) range of 0° to 360° (-180° to +180°), not just 15°. In Fig. 7A and Fig. 7B, the scanning angle range when the optical deflector rotates in the range of 0° to 360° is shown in Fig. 8A and Fig. 8B. The relationship between the deflector angle and the scanning angle in this case is shown in Fig. 9.

[0038] 8A and 8B, the vertical axis indicates the scanning angle range of the light beam, and the horizontal axis indicates the rotation angle of the optical deflector. In Fig. 9, the X-axis direction coincides with the deflector angle of 0 deg, and the Z-axis direction coincides with the scanning angle of 0 deg.

[0039] 8A and 8B, there is a phenomenon in which the light beam is not scanned at an angle of the optical deflector of around 90 degrees (60 degrees to 120 degrees) regardless of whether the rotation axis is set as in Fig. 7A or 7B. This is because, in general, a light beam entering the optical deflector is emitted from a light source, and thereafter a light projection optical system is provided that shapes the light beam to have desired optical characteristics (the present embodiment also has a light projection optical element 20), and in this case, the scanning light beam is vignetted by the light projection optical system itself, so scanning at a scanning angle of 90 degrees is not possible.

[0040] Furthermore, in Fig. 8A, sufficient scanning is not possible at a scanning angle of around -120 deg (-90 deg to -150 deg), and in Fig. 8B, sufficient scanning is not possible at a scanning angle of around -90 deg (-60 deg to -120 deg). This is because the optical deflector itself blocks the light beam, making it impossible to perform optical scanning in the outward direction.

[0041] Therefore, in this embodiment, a technique is devised to expand the scanning range (scanning angle) of the light beam while miniaturizing the optical scanning device 1. Specifically, a first optical deflector 310 is provided as the optical deflector 30, and the first optical deflection surface 311, the rotation axis 312, the arrangement of the optical beam incident on the first optical deflector 310, and the like are devised to increase the optical deflection angle.

[0042] Fig. 10 is a diagram showing an example of the rotation position of the first optical deflector 310 with respect to the light beam. Fig. 11 is a diagram showing another example of the rotation position of the first optical deflector 310 with respect to the light beam. Fig. 12 is a diagram showing the scanning angle range when the first optical deflector 310 rotates in the range of 0 degrees to 360 degrees in Figs. 10 and 11. Fig. 13 is a diagram for explaining the optimum installation position of the first optical deflector 310 with respect to the light beam.

[0043] As shown in Figs. 10 and 11, the first optical deflector 310 has a first optical deflection surface 311 that deflects and scans the optical beam. The first optical deflector 310 is rotatable (rotatable, oscillating) with respect to the optical beam around a rotation axis (rotation axis, oscillation axis) 312 located outside the first optical deflector 310. In Fig. 11, an area used for deflection scanning of the optical beam over the rotation range of the first optical deflector 310 is depicted as the deflector range. Specifically, Fig. 11 depicts a portion where optical deflection is formed in a cross section where the optical beam is incident on the optical deflection surface on a plane including the axis along which the optical beam is scanned and the normal to the optical deflection surface. This is a cross section of the optical deflection surface 311 that is formed around the rotation axis 312 located outside the first optical deflector 310. (External rotating shaft) It can be defined as 312.

[0044] As shown in FIG. 10, the first optical deflector 310 can be rotated to a rotation position where the first optical deflection surface 311 and the light beam are parallel. At the rotation position of the first optical deflector 310 where the first optical deflection surface 311 and the light beam are parallel, the first optical deflection surface 311 and the light beam do not interfere with each other. Specifically, at the rotation position of the first optical deflector 310 where the first optical deflection surface 311 and the light beam are parallel, the first optical deflection surface 311 and the light beam are spaced apart (separated). In other words, at the rotation position of the first optical deflector 310 where the first optical deflection surface 311 and the light beam are parallel, the distance between the first optical deflection surface 311 and the light beam is 0 or more (or larger than 0) with the outside side of the first optical deflector 310 as positive.

[0045] Even in a rotation position of the first optical deflector 310 where the first optical deflection surface 311 and the light beam are slightly misaligned from being parallel (for example, tilted by about 1° to 3°), the first optical deflection surface 311 and the light beam do not necessarily interfere with each other (they may be separated by a distance).

[0046] In this manner, in the optical scanning device 1 of the present embodiment, the first optical deflector 310 is rotatable with respect to the light beam around the rotation axis 312 located outside the first optical deflector 310, and the first optical deflector 310 is rotatable to a rotation position where the first optical deflection surface 311 and the light beam are parallel, and the first optical deflection surface 311 and the light beam do not interfere with each other at the rotation position of the first optical deflector 310 where the first optical deflection surface 311 and the light beam are parallel. Since no significant design change (increase in the number of parts or rearrangement) is required for the optical scanning device 1, the optical scanning device 1 can be made smaller. In addition, since the first optical deflector 310 itself does not vignet the light beam, it is possible to realize a wide-angle projection light (expand the scanning range (scanning angle) of the light beam).

[0047] Also, as shown in Fig. 12, there is no unscannable area other than the vignetting caused by the light projection optical system itself, which occurs near the scanning angle of 90 deg. In other words, there is no unscannable area caused by the optical deflector itself acting as an obstruction, which occurs near the scanning angle of -120 deg in Fig. 8A and near -90 deg in Fig. 8B.

[0048] As shown in FIG. 13, when the distance between first light deflection surface 311 and the light beam at a rotation position where first light deflection surface 311 and the light beam are parallel is D and the beam diameter of the light beam is B, it is preferable to satisfy the following conditional formula (1). (1) D ≥ B / 2

[0049] By satisfying conditional expression (1), it is possible to more effectively suppress vignetting caused by the first optical deflector 310 and reduce ghosts. If conditional expression (1) is not satisfied, the effect of preventing vignetting caused by the first optical deflector 310 may be insufficient, and ghosts may occur.

[0050] Fig. 14 is a diagram showing the spatial profile of the light beam normalized with respect to the Z-axis direction, in which the horizontal axis indicates the Z-axis direction position (mm) and the vertical axis indicates the normalized light beam intensity.

[0051] The beam diameter (light flux diameter) B of the light beam incident on the first optical deflector 310 is defined as the full width at half maximum of the normalized light beam intensity as shown in Fig. 14. From the viewpoint of improving the light utilization efficiency and suppressing ghosting in the optical scanning device, it is necessary to suppress vignetting of the light beam in the optical path. In this case, by setting the distance D between the first optical deflection surface 311 and the light beam to B / 2 or more, it is possible to suppress the light beam being vignetted by the first optical deflector 310, and it is possible to provide an optical scanning device 1 with improved light utilization efficiency and suppressed ghosting.

[0052] FIG. 15 is a diagram showing an example in which a second optical deflector 320 is provided in addition to (separately from) the first optical deflector 310. In FIG.

[0053] The second optical deflector 320 is located between the light source unit 10 and the light projecting optical element 20, and the first optical deflector 310. The second optical deflector 320 has a second optical deflection surface 321 that deflects and scans the light beam. The second optical deflection surface 321 of the second optical deflector 320 deflects and scans the light beam from the light source unit 10 and the light projecting optical element 20, and guides it to the first optical deflector 310.

[0054] By using the first optical deflector 310 and the second optical deflector 320 in combination, it is possible to provide a two-axis optical scanning device 1. Furthermore, the scanning direction of the first optical deflection surface 311 of the first optical deflector 310 and the scanning direction of the second optical deflection surface 321 of the second optical deflector 320 intersect (are perpendicular to) each other. For example, the first optical deflector 310 can perform scanning in the X-axis direction, and the second optical deflector 320 can perform scanning in the Y-axis direction.

[0055] In this way, the light beams from the light source unit 10 and the light projecting optical element 20 are scanned by the second light deflection surface 321 of the second light deflector 320 and then scanned by the first light deflection surface 311 of the first light deflector 310. Here, the scanning angle by the second light deflection surface 321 of the second light deflector 320 is preferably smaller than the scanning angle by the first light polarization surface 311 of the first light deflector 310. The light beam that has passed through the second light deflector 320 enters the first light deflector 310, and at this time, the light beam scanned by the second light deflector 320 is expanded according to the scanning angle and enters the first light deflector 310. The scanning angle of the light beam that enters the first light deflector 310 is preferably small in order to make the first light polarization surface 311 of the first light deflector 310 small. In terms of scanning stability and period, it is better for the first optical deflection surface 311 of the first optical deflector 310 to be small. In addition, by optimally setting the order and scanning angle of the first optical deflector 310 and the second optical deflector 320, it is possible to further reduce the size of the optical scanning device 1.

[0056] Fig. 16 is a diagram showing an example of a preferable arrangement position of the light source unit 10 in the case where only the first optical deflector 310 is provided. As shown in Fig. 16, the light source unit 10 is located outside the scanning locus plane of the light beam scanned by the first optical deflection surface 311 of the first optical deflector 310. This makes it possible to expand the scanning range (scanning angle) of the first optical deflector 310 and to suppress vignetting of the scanning light (light beam) by the light source unit 10.

[0057] Fig. 17 is a diagram showing an example of a preferable arrangement position of the second optical deflector 320 when the first optical deflector 310 and the second optical deflector 320 are provided. As shown in Fig. 17, the second optical deflector 320 is located outside the scanning locus plane of the light beam scanned by the first optical deflection surface 311 of the first optical deflector 310. This makes it possible to expand the scanning range (scanning angle) of the first optical deflector 310 and to suppress vignetting of the scanning light (light beam) by the second optical deflector 320.

[0058] In this manner, in the present embodiment, for example, in an optical scanning device used in LiDAR, by providing the element center and the rotation axis (rotation axis, swing axis) of the scanning element (for example, the first optical deflector) differently, it is possible to suppress the reduction of the projection range due to the vignetting of the light ray (light beam) by the scanning element itself. In addition, by rotating the deflection surface (for example, the first optical deflection surface) of the scanning element (for example, the first optical deflector) including the state where it is parallel to the incident light beam, and arranging the deflection surface so that the light beam does not interfere with the incident light beam in the state where the deflection surface is parallel to the deflection surface, it is possible to enlarge the scanning range (scanning angle) of the light beam while miniaturizing the optical scanning device. Furthermore, by using the front and back surfaces (for example, not only the first optical deflection surface but also the surface located on the opposite side) of the plate-shaped scanning element (for example, the first optical deflector), it is possible to further enlarge the scanning range of the light beam. [Explanation of symbols]

[0059] 1 Optical scanning device 2. Object detection device 3. Sensing equipment 4. Monitoring and control equipment 5. Automobiles (mobile objects) 10 Light source section 20 Light projection optical element 30 Optical deflector (scanning mirror) 31 Light deflection surface 40 Light receiving optical system 50 Light receiving optical element (object detection section) 60 Drive Board 70 Waveform processing circuit 80 Time measurement circuit 90 Measurement control section 100 Light source driving circuit 110 Image acquisition unit 120 Image Processing Unit 130 Information Complex Department 310 First optical deflector 311 First light deflection surface 312 Rotating shaft ( External pivot shaft, Rotating shaft, swing shaft) 320 Second Optical Deflector 321 Second light deflection surface

Claims

1. A light source unit that emits a light beam; a first optical deflector having a first optical deflection surface for deflecting and scanning the light beam; having the first optical deflection surface is provided on a side of the first optical deflector on which the light beam is incident, an external rotation axis located outside the first optical deflector is set to face the first optical deflection surface and be spaced apart from the first optical deflection surface; the first optical deflector is rotatable relative to the light beam about the external pivot axis; the first optical deflector is rotatable to a rotation position where the first optical deflection surface and the light beam are parallel to each other; At the rotation position where the first light deflection surface and the light beam are parallel to each other, the first light deflection surface and the light beam are spaced apart from each other with a gap therebetween, and the first light deflection surface and the light beam do not interfere with each other.

1. An optical scanning device comprising:

2. When a distance between the first light deflection surface and the light beam at the rotation position where the first light deflection surface and the light beam are parallel is D and a beam diameter of the light beam is B, the following conditional expression (1) is satisfied:

2. The optical scanning device according to claim 1. (1) D ≧ B / 2

3. the light source unit is located outside a scanning locus plane of the light beam scanned by the first light deflection surface of the first light deflector; 3. The optical scanning device according to claim 1, wherein the first and second optical fibers are arranged in a first direction.

4. a second optical deflector having a second optical deflection surface for deflecting and scanning the light beam; a scanning direction by the first optical deflection surface of the first optical deflector and a scanning direction by the second optical deflection surface of the second optical deflector intersect with each other; 4. The optical scanning device according to claim 1, wherein the first and second optical fibers are arranged in a first direction.

5. the light beam is scanned by the second light deflection surface of the second light deflector and then scanned by the first light deflection surface of the first light deflector; a scanning angle by the first optical deflection surface of the first optical deflector is larger than a scanning angle by the second optical deflection surface of the second optical deflector; 5. The optical scanning device according to claim 4.

6. the second optical deflector is positioned outside a scanning locus plane of the light beam scanned by the first optical deflection surface of the first optical deflector; 6. The optical scanning device according to claim 5.

7. An optical scanning device according to any one of claims 1 to 6, an object detection unit that detects light reflected or scattered by an object present in a detection area from the light beam from the light source unit and determines a timing for detecting the object; having An object detection device, comprising: a light source unit that detects information about the object based on a light emission timing of the light source unit and a timing of the object detection;

8. an image acquisition unit for acquiring an image of an object present in a detection area; an image processing unit that processes the image of the object acquired by the image acquisition unit to generate image information; an information combining unit that combines the image information and the object information; The object detection device according to claim 7, further comprising:

9. An object detection device according to claim 7 or 8; a monitoring control device that acquires information including at least one of the presence or absence of the object, the moving direction of the object, and the moving speed of the object based on an output of the object detection device; A sensing device comprising:

10. A moving body equipped with the sensing device according to claim 9, The monitoring and control device controls the movement of the moving body based on at least one of the position information and the movement information of the object. A moving object characterized by:

Images