JP7647151B2 - Optical scanning device, object detection device, sensing device and moving body - Google Patents

Description

The present invention relates to an optical scanning device, an object detection device, a sensing device, and a moving body.

For example, in the operation of moving objects such as vehicles, ships, and aircraft, technology is 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 to measure the distance to an object from the time it takes for 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, and this allows the position information of the object to be obtained over a wide angular range.

Patent document 1 describes a LIDAR system that includes at least one processor. This LIDAR system causes light emitted from multiple 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. Also, controls at least one light deflector to deflect the light from the at least one light source to scan the field of view. Also, a first detected reflection associated with the scanning of a first portion of the field of view is used to determine that a first object is present in the first portion at a first distance. Also, determines that an object is absent in a second portion of the field of view at the first distance. Also, after detecting the first reflection and determining that an object is absent in the second portion, light source parameters are changed so 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. Also, a second detected reflection in the second portion of the field of view is used to determine that a second object is present at a second distance greater than the first distance.

Special table 2019-535014 publication

However, with conventional distance measuring devices, including that of Patent Document 1, it has been difficult to simultaneously create a system that is both compact and can measure distances at a wide angle. For example, optical distance measuring systems such as Velodyne use 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 achieving a wide angle using multiple light sources, such as with Innoviz, the system becomes large due to the arrangement of multiple light sources and the layout of the optical path.

The present invention was made based on the above concerns, and aims to provide an optical scanning device, object detection device, sensing device, and moving body that can be made smaller and have a wider angle.

The optical scanning device of this embodiment has 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 the incident surface side of the light beam in the first optical deflector, an external rotation axis located outside the first optical deflector is set opposite the first optical deflection surface and spaced apart from the first optical deflection surface, the first optical deflector is freely rotatable relative to the light beam around the external rotation axis , the first optical deflector is freely rotatable to a rotation position where the first optical deflection surface and the light beam are parallel, and at the parallel rotation position, the first optical deflection surface and the light beam are separated by a gap, and there is no interference between the first optical deflection surface and the light beam.

The present invention provides an optical scanning device, an object detection device, a sensing device, and a moving object that can be made compact and have a wide angle.

1 is a diagram illustrating an example of a configuration of an optical scanning device according to an embodiment of the present invention. 5 is a diagram showing various parameters in the optical scanning device according to the present embodiment. FIG. 1 is a diagram illustrating an example of a configuration of an object detection device according to an embodiment of the present invention. FIG. 1 is a functional block diagram of an object detection device that realizes distance measurement using a TOF method. FIG. 1 is a diagram illustrating an example of a configuration of a sensing device according to an embodiment of the present invention. FIG. 1 is a diagram showing an automobile as an example of a moving body according to an embodiment of the present invention. FIG. 1 is a diagram illustrating an example of an optical deflector according to a comparative example. 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. 11 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. 5A and 5B are diagrams illustrating an example of a rotational position of a first optical deflector with respect to a light beam. 11A and 11B are diagrams illustrating other examples of rotation positions of the first optical deflector with respect to the light beam. 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. 5 is a diagram for explaining an optimum installation position of the first optical deflector with respect to the light beam; FIG. FIG. 13 is a diagram showing a spatial profile of a light beam normalized with respect to the Z-axis direction. FIG. 13 is a diagram showing an example in which a second optical deflector is provided in addition to the first optical deflector. 13 is a diagram showing an example of a preferable arrangement position of a light source unit when only a first optical deflector is provided; FIG. 13 is a diagram showing an example of a preferable arrangement position of the second optical deflector when the first optical deflector and the second optical deflector are provided; FIG.

Below, an example of an optical scanning device, object detection device, sensing device, and moving body according to this embodiment will be described. This embodiment can be applied to sensing devices mounted on moving bodies such as vehicles, ships, and aircraft, robots used in factories and warehouses, and various drones. This embodiment can also be applied to optical projection devices such as three-dimensional measurement devices. In addition, this embodiment can be applied to optical scanning devices, object detection devices, sensing devices, and moving bodies in all current and future technical fields.

In the following explanation, the X-axis, Y-axis, and Z-axis directions are based on the arrow directions shown in the figure. The X-axis, Y-axis, and Z-axis directions form a three-dimensional space that is orthogonal to each other.

Figure 1 shows an example of the configuration of an optical scanning device 1 according to this embodiment.

The optical scanning device 1 has a light source unit 10, a light projecting optical element 20, and an optical deflector (scanning mirror) 30. Details will be described later, but 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, etc. 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.

The light source unit 10 emits a light beam that diverges 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.

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 incident light beam, which diverges 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 diverging light beam and shapes it into a substantially parallel beam. Note that while the light projecting optical element 20 is depicted as a single lens in FIG. 1, the light projecting optical element 20 may also be composed of multiple lenses.

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 with a solid line, and the scanning position of the optical deflector 30 (optical deflection surface 31) (for example, a position intermediate between the reference position and both scanning end positions) is drawn with a dashed line.

Figure 2 shows various parameters in the optical scanning device 1 according to this embodiment.

In Fig. 2, θ indicates a half angle of a predetermined angle (divergence angle) of a 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 defined as an angle at which the intensity is expressed as 1/ ^e2 of the peak intensity in the profile of the light beam from the light source unit 10 (the angle formed by the center direction and the direction at which the intensity is 1/ ^e2 of the peak intensity). 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 light output by the light source unit 10. This makes it possible to suppress loss of the light amount from the light source unit 10 and to miniaturize the light projecting optical element 20.

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 of that length is the half-width a of the size of the light deflection surface 31.

In FIG. 2, f indicates the focal length of the light-projecting optical element 20. As shown in FIG. 2, 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 arranged to be equal to the focal length f of the light-projecting optical element 20. This causes the light beam from the light source unit 10 to be shaped by the light-projecting optical element 20 to become approximately parallel light.

In FIG. 2, α indicates the angle of incidence of the light beam on 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.

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 = 2f tan θ

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 luminous flux 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

Figure 3 is a diagram showing an example of the configuration of an object detection device 2 according to this embodiment. 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, the object detection device 2 has a light receiving optical system 40, a light receiving optical element 50, and a drive board 60.

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 about the object can be detected based on the 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 about the object can be detected based on the emission information of the light beam emitted from the light source unit 10 and the 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.

The light receiving optical system 40 can be, for example, one of a variety of configurations that can focus light on the light receiving optical element 50, such as a lens system, a mirror system, and the like (the configuration of the light receiving optical system 40 has a degree of freedom and is not limited to a specific configuration).

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) with a TOF (Time of Flight) calculation function for each pixel.

Figure 4 is a functional block diagram of an object detection device 2 that realizes distance measurement using the TOF method. As shown in Figure 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.

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 (light emission timing of the light source unit 10 and object detection timing of the light receiving optical element 50) from the light emission timing of the light source unit 10 input from the time measurement circuit 80. 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.

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

The image acquisition unit 110 is composed of, for example, an image sensor (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 a distance measurement object present in the detection area and distance information (distance measurement information) of the distance measurement object, and can be used by being displayed on a display (not shown) or stored in a memory (not shown).

Figure 5 is a diagram showing an example of the configuration of the sensing device 3 according to this embodiment. The sensing device 3 has the object detection device 2 and the monitoring control device 4 described above. The object detection device 2 and the monitoring control device 4 are electrically connected.

Figure 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 while 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.

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

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 light beam from a light source unit and a light projecting optical element (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 the time when the rotation axis is set so that the distance between the light 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 the time when the rotation axis is set so that the distance between the light 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.

The rotational 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 in both Figures 7A and 7B that the light beam is deflected and scanned.

However, optical deflectors intended for wide-angle scanning are required to scan light over a wide range of rotation (rotation, swing) from 0 to 360 degrees (-180 to +180 degrees), not just 15 degrees. In Figures 7A and 7B, the scanning angle range when the optical deflector rotates in the range of 0 to 360 degrees is shown in Figures 8A and 8B. The relationship between the deflector angle and the scanning angle at that time is shown in Figure 9.

In Figures 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 Figure 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.

As shown in Figures 8A and 8B, regardless of whether the rotation axis is set to Figure 7A or Figure 7B, 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). This is because, in general, the light beam that enters the optical deflector is emitted from a light source, and there is often a light projection optical system that then shapes the light beam to the 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.

Furthermore, in Figure 8A, sufficient scanning is not possible at a scanning angle of around -120 deg (-90 deg to -150 deg), and in Figure 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.

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

Figure 10 is a diagram showing an example of the rotational position of the first optical deflector 310 relative to the light beam. Figure 11 is a diagram showing another example of the rotational position of the first optical deflector 310 relative to the light beam. Figure 12 is a diagram showing the scanning angle range when the first optical deflector 310 in Figures 10 and 11 rotates in the range of 0 degrees to 360 degrees. Figure 13 is a diagram for explaining the optimal installation position of the first optical deflector 310 relative to the light beam.

As shown in Fig. 10 and Fig. 11, the first optical deflector 310 has a first optical deflection surface 311 for deflecting and scanning 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, the 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 in a plane including the axis along which the optical beam is scanned and the normal line to the optical deflection surface. This can be defined as a rotation axis (external rotation axis) 312 located outside the first optical deflector 310.

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 is greater than 0) with the outside side of the first optical deflector 310 as positive.

Note that even in a rotational 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 have to interfere with each other (they may be spaced apart).

In this way, in the optical scanning device 1 of this 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, wide-angle projection light can be realized (the scanning range (scanning angle) of the light beam can be expanded).

As shown in Figure 12, there are no unscannable areas other than vignetting caused by the projection optical system itself, which occurs near a scanning angle of 90 degrees. In other words, there are no unscannable areas caused by the optical deflector itself acting as an obstruction, which occurs near a scanning angle of -120 degrees in Figure 8A and near -90 degrees in Figure 8B.

As shown in Figure 13, when the distance between the first light deflection surface 311 and the light beam at a rotation position where the 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 expression (1).
(1) D ≧ B / 2

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

Figure 14 shows the spatial profile of the light beam normalized in the Z-axis direction. In Figure 14, the horizontal axis shows the Z-axis position (mm), and the vertical axis shows the normalized light beam intensity.

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.

Figure 15 shows an example of a case where a second optical deflector 320 is provided in addition to (separately from) the first optical deflector 310.

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.

By using the first optical deflector 310 and the second optical deflector 320 together, a two-axis optical scanning device 1 can be provided. 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.

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, it is preferable that the scanning angle by the second light deflection surface 321 of the second light deflector 320 is 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 that 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. It is preferable that the scanning angle of the light beam that enters the first light deflector 310 is small in order to make the first light polarization surface 311 of the first light deflector 310 small. The first optical deflection surface 311 of the first optical deflector 310 is preferably small in terms of scanning stability and period. 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.

Figure 16 is a diagram showing an example of a preferred position for the light source unit 10 when only the first optical deflector 310 is provided. As shown in Figure 16, the light source unit 10 is located outside the scanning trajectory 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 suppress vignetting of the scanning light (light beam) by the light source unit 10.

Figure 17 is a diagram showing an example of a preferred position of the second optical deflector 320 when the first optical deflector 310 and the second optical deflector 320 are provided. As shown in Figure 17, the second optical deflector 320 is located outside the scanning trajectory 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 suppress vignetting of the scanning light (light beam) by the second optical deflector 320.

In this way, in the present embodiment, for example, in an optical scanning device used in LiDAR, by setting the element center and the rotation axis (rotation axis, oscillation axis) of the scanning element (e.g., the first optical deflector) to be different, it is possible to suppress the light beam (light beam) being vignetted by the scanning element itself and the reduction in the projection range. In addition, by rotating the deflection surface (e.g., the first optical deflector) of the scanning element (e.g., 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 and the deflection surface are parallel, it is possible to miniaturize the optical scanning device while expanding the scanning range (scanning angle) of the light beam. Furthermore, by using the front and back surfaces (e.g., not only the first optical deflection surface but also the surface located on the opposite side) of the plate-shaped scanning element (e.g., the first optical deflector), the scanning range of the light beam can be further expanded.

1 Optical scanning device 2 Object detection device 3 Sensing device 4 Monitoring and control device 5 Automobile (mobile body)
10 Light source unit 20 Light projecting optical element 30 Optical deflector (scanning mirror)
31 Light deflection surface 40 Light receiving optical system 50 Light receiving optical element (object detection unit)
60 Drive board 70 Waveform processing circuit 80 Time measurement circuit 90 Measurement control section 100 Light source drive circuit 110 Image acquisition section 120 Image processing section 130 Information composite section 310 First optical deflector 311 First optical deflection surface 312 Rotation axis ( external rotation axis, rotation axis, oscillation axis)
320 Second optical deflector 321 Second optical deflection surface

Claims (10)

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 optical 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: 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 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. 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. 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 . 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 . 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; 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: 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: 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:

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