Optical scanner and object detection device

Abstract

To provide an optical scanner capable of significantly changing the angle of view at optical scanning time and an object detection device equipped with the same.SOLUTION: Provided is an optical scanner used in a device for performing object detection by emitting light and receiving its reflected light. The optical scanner includes: a deflector; at least one light source; a polarization variable element located so that light generated by the light source enters and emitting first outgoing light composed mainly of first light in a first polarization state or emits second outgoing light composed mainly of second light in a second polarization state different from the first polarization state; a branch element for causing the first light and the second light to be branched in different travel directions; and an optical system for causing the first light branched by the branch element to enter the deflector at a first angle and causing the second light branched by the branch element to enter the deflector at a second angle different from the first angle.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an optical scanning device and an object detection device. [Background technology]

[0002] Conventional examples of optical scanning devices and object detection devices are described in, for example, Japanese Patent Application Laid-Open No. 2010-151958 (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-151958 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of a specific embodiment of the present disclosure is to provide an optical scanning device capable of greatly changing the angle of view during optical scanning, and an object detection device including the same. [Means for solving the problem]

[0005] [1] An optical scanning device according to one aspect of the present disclosure includes: An optical scanning device used in a device that detects an object by irradiating light and receiving reflected light, A deflector; At least one light source; a polarization variable element that is disposed so that light emitted from the light source is incident thereon and that outputs a first output light mainly including a first light in a first polarization state or a second output light mainly including a second light in a second polarization state different from the first polarization state; A branching element that branches the first light and the second light into light traveling in different directions; an optical system that causes the first light branched by the branching element to be incident on the deflector at a first angle and causes the second light branched by the branching element to be incident on the deflector at a second angle different from the first angle; The optical scanning device includes: [2] An object detection device according to one aspect of the present disclosure, The optical scanning device according to [1] above; a light receiving section that detects reflected light caused by irradiation light emitted from the optical scanning device and generates a light receiving signal corresponding to the intensity of the reflected light; a control unit that controls an operation of the optical scanning device and generates point cloud information based on the light receiving signal; The object detection device includes:

[0006] According to the above configuration, it is possible to provide an optical scanning device capable of greatly changing the angle of view during optical scanning, and an object detection device including the same. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a configuration of an object detection device according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining the optical configuration of the scanning light source unit. [Diagram 3] Fig. 3(A) is a diagram showing the layout of the optical configuration in the xy plane when the first optical path is used, and Fig. 3(B) is a diagram showing the layout of the optical configuration in the xz plane when the first optical path is used. [Figure 4] Fig. 4(A) is a diagram showing the layout of the optical configuration in the xy plane when the second optical path is used. Fig. 4(B) is a diagram showing the layout of the optical configuration in the xz plane when the second optical path is used. [Diagram 5] Fig. 5(A) is a diagram for explaining the angle of view when the first optical path is used, and Fig. 5(B) is a diagram for explaining the angle of view when the second optical path is used. [Figure 6] Fig. 6(A) is a diagram showing the angle of view formed on both sides of the normal c to the MEMS mirror when the first optical path is used, and Fig. 6(B) is a diagram showing the angle of view formed on both sides of the normal c to the MEMS mirror when the second optical path is used. [Figure 7] 7A and 7B are diagrams showing the angle of view of modified examples. [Figure 8] FIG. 8 is a flowchart showing the operation procedure of the object detection device 1 when variably setting the angle of view according to the vehicle speed. [Figure 9] 9(A) and 9(B) are diagrams showing configuration examples of an object detection device according to a modified embodiment. [Figure 10] 10(A) and 10(B) are diagrams showing configuration examples of an object detection device according to a modified embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1 is a diagram showing the configuration of an object detection device according to an embodiment. The object detection device 1 according to this embodiment is for performing optical scanning in a target space using a plurality of laser lights (detection lights), receiving reflected light, and detecting point cloud information indicating the position and relative distance of an object present in the target space using the reflected light, and is configured to include a control unit (controller) 10, a scanning light source unit (optical scanning device) 20, and a light receiving unit 30. This object detection device 1 is mounted on, for example, a vehicle and used to detect objects (other vehicles, pedestrians, etc.) around the vehicle. In this case, the object detection device 1 can be disposed, for example, on the roof of the vehicle, near an emblem, near a rearview mirror, inside a headlamp, etc.

[0009] The control unit 10 controls the overall operation of the object detection device 1, and includes a measurement control unit 11, a deflection control unit 12, a polarization control unit 13, a lighting control unit 14, a distance measurement unit 15, and a communication unit 16. This control unit 10 can be realized by using a computer system equipped with, for example, a CPU, a ROM, a RAM, etc., and causing the computer system to execute a predetermined operation program.

[0010] The measurement control unit 11 controls the operation of the deflection control unit 12, the polarization control unit 13, the lighting control unit 14, and the distance measurement unit 15, and also controls the communication unit 16 to transmit point cloud information, which is the measurement result of the distance measurement unit 15, to an external device not shown.

[0011] The deflection control unit 12 controls the MEMS mirror 22 via the MEMS driver 21 of the scanning light source unit 20 so as to periodically deflect the MEMS mirror 22 in a specified angle change pattern (typically, a raster scan with equal scanning line intervals).

[0012] The polarization control unit 13 controls the operation of each of the polarization variable elements 24 a and 24 b via a polarization variable element driver 23 .

[0013] The lighting control unit 14 controls the light source driver 25 so that the light sources 26 a and 26 b emit laser light under the pulse conditions instructed by the measurement control unit 11 .

[0014] The distance measurement unit 15 measures the distance between an object in the target space based on the time difference between the emission time and the reception time of the laser light, using the timing of the instruction to generate the laser light from the lighting control unit 14 and the light reception signal obtained from the light receiving circuit 34 of the light receiving unit 30. In addition, the three-dimensional position of the object is detected by the measurement control unit 11 based on the emission time and the reception time of the laser light.

[0015] The communication unit 16 transmits the obtained point cloud information (a set of three-dimensional positions) to an external device (not shown). The communication processing unit 16 also receives vehicle speed information from a vehicle control device (not shown).

[0016] The scanning light source unit 20 generates a narrow-angle beam of laser light and emits it in various directions within a predetermined range, and is composed of a MEMS driver (second driver) 21, a MEMS mirror 22, a polarization variable element driver (third driver) 23, two polarization variable elements 24a, 24b, a light source driver (first driver) 25, and two light sources 26a, 26b.

[0017] The MEMS driver 21 is connected to the MEMS mirror 22 , and under the control of the deflection control unit 12 of the control unit 10 , generates a drive signal that controls the operation of the MEMS mirror 22 and supplies it to the MEMS mirror 22 .

[0018] The MEMS mirror 22 is a two-dimensional deflector having a reflecting surface and configured to be rotatable in two orthogonal directions. The MEMS mirror 22 is disposed at a position where the laser beams emitted from the light sources 26a and 26b can be incident on the reflecting surface from different directions, and rotates based on a drive signal supplied from the MEMS driver 21 to scan the laser beams in the target space. The laser beams are emitted from an opening appropriately provided in the scanning light source unit 20 into the external target space.

[0019] The polarization variable element driver 23 is connected to each polarization variable element 24a, 24b, and under the control of the polarization control unit 13 of the control unit 10, generates drive signals that control the operation of each polarization variable element 24a, 24b and supplies them to each polarization variable element 24a, 24b.

[0020] Each of the polarization variable elements 24a and 24b is an element capable of rotating the polarization direction (polarization plane) of the incident light. For example, a liquid crystal polarization rotator or an electro-optical modulator can be used as such polarization variable elements 24a and 24b. The rotation angle of the polarization direction can be controlled by the magnitude of the voltage applied to each of the polarization variable elements 24a and 24 by the polarization variable element driver 23. The polarization variable elements 24a and 24b are arranged so that light emitted from a light source is incident thereon, and emit an output light mainly composed of a first light in a first polarization state or an output light mainly composed of a second light in a second polarization state different from the first polarization state. For example, the polarization variable elements 24a and 24b emit an output light containing 95% or more of the first light in the first polarization state or an output light containing 95% or more of the second light in a second polarization state different from the first polarization state.

[0021] The light source driver 25 is connected to each of the light sources 26a, 26b, and under the control of the lighting control unit 14 of the control unit 10, generates a drive signal that controls the operation of each of the light sources 26a, 26b and supplies it to each of the light sources 26a, 26b.

[0022] Each of the light sources 26a, 26b generates a narrow-angle beam (beam with a small divergence angle) of laser light as detection light and emits the laser light. The laser light emitted from each of the light sources 26a, 26b is a beam with a divergence angle that is comparable to (the same as or smaller than) the angular resolution of the object detection device 1. Each of the light sources 26a, 26b can be, for example, a near-infrared photonic crystal laser (PCSEL), but is not limited thereto, and any light source capable of emitting a narrow-angle beam of detection light may be used.

[0023] The light receiving unit 30 receives reflected light caused by the laser light emitted from each of the light sources 26a, 26b to generate a light receiving signal, and is configured to include a lens 31, an optical filter 32, a photodetector (light receiving element) 33, and a light receiving circuit 34. The light receiving unit 30 may be configured as a coaxial optical system that receives light along the same optical path as the optical path from each of the light sources 26a, 26b to the MEMS mirror 22, or may be configured as a non-coaxial optical system that does not use the same optical path.

[0024] The lens 31 collects reflected light generated by the laser light emitted from each of the light sources 26a, 26b. The optical filter 32 blocks light in a wavelength range different from that of the laser light emitted from each of the light sources 26a, 26b and transmits light in the same wavelength range as the laser light emitted from each of the light sources 26a, 26b. The photodetector 33 detects the light incident via the optical filter 32.

[0025] The light receiving circuit 34 generates a light receiving signal by performing predetermined signal processing (e.g., amplification, frequency filtering, etc.) on the output of the photodetector 33. The generated light receiving signal is supplied to the distance measuring unit 15 of the control unit 10.

[0026] FIG. 2 is a diagram for explaining the optical configuration of the scanning light source unit. The laser light emitted from the light source 26a is, for example, p-polarized light, is emitted parallel to the y-axis shown in the figure, and enters the polarization variable element 24a. The polarization variable element 24a does not rotate the polarization direction when the voltage is off, and rotates the polarization direction by 90° when the voltage is on. Therefore, when the voltage is off, the p-polarized laser light that entered the polarization variable element 24a passes through the polarization variable element 24a with the same polarization direction, and enters the polarization beam splitter (splitting element) 40a. This p-polarized laser light passes through the polarization beam splitter 40a and enters the mirror 41a, is reflected by the mirror 41a, and enters the MEMS mirror 22. The laser light that entered the MEMS mirror 22 is reflected by the MEMS mirror 22.

[0027] On the other hand, when the voltage is on, the p-polarized laser light incident on the polarization variable element 24a becomes s-polarized light, with its polarization direction rotated by 90 degrees, passes through the polarization variable element 24a, and enters the polarization beam splitter 40a. The s-polarized laser light is reflected by the polarization beam splitter 40a in a direction parallel to the x-axis and enters the mirror 42a, is reflected by the mirror 42a, and is further reflected by the mirror 43a and enters the MEMS mirror 22. The laser light incident on the MEMS mirror 22 is reflected by the MEMS mirror 22.

[0028] In other words, in the scanning light source section 20 of this embodiment, the polarization direction of the laser light can be variably set depending on the voltage applied to the polarization variable element 24a, so that two optical paths can be selectively used: a first optical path (shown by a solid line in the figure) that passes through the polarizing beam splitter 40a and the mirror 41a to the MEMS mirror 22, and a second optical path (shown by a dotted line in the figure) that passes through the polarizing beam splitter 40a, the mirror 42a and the mirror 43a to the MEMS mirror 22.

[0029] Similarly, the laser light emitted from the light source 26b is, for example, p-polarized light, is emitted parallel to the y-axis shown in the figure, and enters the polarization variable element 24b. The polarization variable element 24b does not rotate the polarization direction when the voltage is off, and rotates the polarization direction by 90° when the voltage is on. Therefore, when the voltage is off, the p-polarized laser light that entered the polarization variable element 24b passes through the polarization variable element 24b with the polarization direction unchanged, and enters the polarization beam splitter (splitting element) 40b. This p-polarized laser light passes through the polarization beam splitter 40b, enters the mirror 41b, is reflected by the mirror 41b, and enters the MEMS mirror 22. The laser light that entered the MEMS mirror 22 is reflected by the MEMS mirror 22.

[0030] On the other hand, when the voltage is on, the p-polarized laser light incident on the polarization variable element 24b becomes s-polarized light, with its polarization direction rotated by 90 degrees, passes through the polarization variable element 24b, and enters the polarization beam splitter 40b. This s-polarized laser light is reflected by the polarization beam splitter 40b in a direction parallel to the x-axis and enters the mirror 42b, is reflected by the mirror 42b, and is further reflected by the mirror 43b and enters the MEMS mirror 22. The laser light incident on the MEMS mirror 22 is reflected by the MEMS mirror 22.

[0031] In other words, in the scanning light source section 20 of this embodiment, the polarization direction of the laser light can be variably set depending on the voltage applied to the polarization variable element 24b, so that two optical paths can be selectively used: a first optical path (shown by a solid line in the figure) that passes through the polarizing beam splitter 40b and the mirror 41b to the MEMS mirror 22, and a second optical path (shown by a dotted line in the figure) that passes through the polarizing beam splitter 40b, the mirror 42b and the mirror 43b to the MEMS mirror 22.

[0032] The mirrors 41a, 42a, and 43a are fixedly disposed so as to cause the light emitted from the light source 26a and passing through the polarization variable element 24a to be incident on the MEMS mirror 22. The mirrors 41b, 42b, and 43b are fixedly disposed so as to cause the light emitted from the light source 26b and passing through the polarization variable element 24b to be incident on the MEMS mirror 22.

[0033] The mirrors 41a and 41b are disposed at positions such that the angles at which the light reflected by each mirror is incident on the MEMS mirror 22a are substantially symmetrical with respect to the center of the MEMS mirror 22a in the x-axis direction.

[0034] Furthermore, mirror 43a and mirror 43b are disposed at positions such that the angles at which light reflected by each mirror is incident on MEMS mirror 22a are approximately symmetrical with respect to the center of MEMS mirror 22a in the x-axis direction.

[0035] FIG. 3(A) is a diagram showing the arrangement of the optical configuration in the xy plane when the first optical path is used. FIG. 3(B) is a diagram showing the arrangement of the optical configuration in the xz plane when the first optical path is used. In FIG. 3(A), the light reflected by the mirror 22 is shown diagonally for convenience, but in reality, the light travels toward the front side of the paper. In FIG. 3(B), only the path from the mirror 41a to the MEMS mirror 22 is shown for ease of understanding. In addition, here, the first optical path from the polarizing beam splitter 40a to the mirror 41a to the MEMS mirror 22 is shown, and the first optical path from the polarizing beam splitter 40b to the mirror 41b to the MEMS mirror 22 is similar, so illustration and description are omitted.

[0036] As described above, when the first optical path is used, the p-polarized laser light emitted from the light source 26a passes through the polarization variable element 24a while maintaining its polarization direction, passes through the polarizing beam splitter 40a, and enters the mirror 41a, and is reflected by the mirror 41a and enters the MEMS mirror 22 (see FIG. 3(A)). The relative positions of the mirror 41a and the MEMS mirror 22 are set so that the laser light entering the MEMS mirror 22 from the mirror 41a is incident at an incident angle θ1 with respect to the normal direction at the reference position of the MEMS mirror 22 (see FIG. 3(B)). The laser light entering the MEMS mirror 22 is reflected by the MEMS mirror 22.

[0037] FIG. 4(A) is a diagram showing the arrangement of the optical configuration in the xy plane when the second optical path is used. FIG. 4(B) is a diagram showing the arrangement of the optical configuration in the xz plane when the second optical path is used. In FIG. 4(A), the light reflected by the mirror 22 is shown diagonally for convenience, but in reality, the light travels toward the front side of the paper. In addition, in FIG. 4(B), only the path from the mirror 41a to the MEMS mirror 22 is shown for ease of understanding. In addition, here, the second optical path from the polarizing beam splitter 40a to the mirror 41a to the MEMS mirror 22 is shown, and the second optical path from the polarizing beam splitter 40b to the mirror 41b to the MEMS mirror 22 is similar, so illustration and description are omitted.

[0038] As described above, when the second optical path is used, the p-polarized laser light emitted from the light source 26a has its polarization direction rotated by 90° by the polarization variable element 24a to become s-polarized light, passes through the polarization variable element 24a, is reflected by the polarizing beam splitter 40a, is incident on the mirror 42a, is reflected by the mirror 42a, is incident on the mirror 43a, and is reflected by the mirror 43a to be incident on the MEMS mirror 22 (see FIG. 4(A)). The relative positions of the mirror 43a and the MEMS mirror 22 are set so that the laser light incident on the MEMS mirror 22 from the mirror 43a is incident at an incident angle θ2 (<θ1) with respect to the normal direction at the reference position of the MEMS mirror 22 (see FIG. 3(B)). The laser light incident on the MEMS mirror 22 is reflected by the MEMS mirror 22.

[0039] Fig. 5(A) is a diagram for explaining the angle of view when the first optical path is used. Fig. 5(B) is a diagram for explaining the angle of view when the second optical path is used. As described above, in this embodiment, the optical configuration is arranged so that the angle of incidence θ2 of the laser light incident on the MEMS mirror 22 when the second optical path is used is relatively smaller than the angle of incidence θ1 of the laser light incident on the MEMS mirror 22 when the first optical path is used.

[0040] When the first optical path is used, for example, by setting the optical deflection angle θxsc1 in the x-axis direction of the MEMS mirror 22 to twice the incident angle θ1, a relatively wide range of field of view (FOV) can be formed. The field of view formed here is theoretically formed in a fan shape in the upper region in the figure from the normal c of the MEMS mirror 22 as shown in the figure. Similarly, the field of view formed by using the laser light emitted from the light source 26b is theoretically formed in a fan shape in the lower region in the figure from the normal c of the MEMS mirror 22. As an example, θ1 can be set to 15° and θxsc1 to 30°.

[0041] When the second optical path is used, for example, by setting the optical deflection angle θxsc2 in the x-axis direction of the MEMS mirror 22 to twice the incident angle θ2, a relatively narrow range of field of view (FOV) can be formed. The field of view formed here is theoretically formed in a fan shape in the upper region in the figure from the normal c of the MEMS mirror 22 as shown in the figure. Similarly, the field of view formed by using the laser light emitted from the light source 26b is theoretically formed in a fan shape in the lower region in the figure from the normal c of the MEMS mirror 22. As an example, θ2 can be set to 7.5° and θxsc2 to 15°.

[0042] Fig. 6A is a diagram showing the field of view (FOV) formed on both sides of the normal line c of the MEMS mirror when the first optical path is used. In Fig. 6A, the field of view formed by the first optical path in which light is emitted from the light source 26a and enters the MEMS mirror 22 via the mirror 41a is shown above the normal line c, and the field of view formed by the first optical path in which light is emitted from the light source 26b and enters the MEMS mirror 22 via the mirror 41b is shown below the normal line c.

[0043] Fig. 6B is a diagram showing the field of view (FOV) formed on both sides of the normal line c of the MEMS mirror when the second optical path is used. In Fig. 6B, the field of view formed by the second optical path incident on the MEMS mirror 22 via the mirror 43a is shown above the normal line c, and the field of view formed by the second optical path incident on the MEMS mirror 22 via the mirror 43b is shown below the normal line c.

[0044] In FIG. 6(A), the angle of view formed by the first optical path that enters the MEMS mirror 22 via mirror 41a and the angle of view formed by the first optical path that enters the MEMS mirror 22 via mirror 41b are formed so as to be continuous without any gaps.

[0045] In addition, in FIG. 6(B), the angle of view formed by the second optical path that enters the MEMS mirror 22 via mirror 43a and the angle of view formed by the second optical path that enters the MEMS mirror 22 via mirror 43b are formed so as to be continuous without any gaps.

[0046] Therefore, the angle of view formed by the two light sources 26a, 26b can be formed so as to be continuous without any gaps, whether it is formed by the first optical path or the second optical path.

[0047] As shown in each figure, the angle of view is relatively wide when the first optical path is used, and is relatively narrow when the second optical path is used. As a result, when the number of laser beam hits per frame is fixed, the angular resolution is relatively higher when the second optical path is used than when the first optical path is used.

[0048] For example, the MEMS mirror 22 is a two-axis MEMS mirror with a resonant axis and a non-resonant axis, the resonant axis is the x-axis, the non-resonant axis is the y-axis, and the frequency of the resonant axis is 22 kHz and the frequency of the non-resonant axis is 120 Hz whether the first optical path or the second optical path is used. Also, the optical deflection angle is twice the mechanical deflection angle of the MEMS mirror 22. In this case, if the optical deflection angle θxsc=30° on the x-axis when the first optical path is used, the optical deflection angle θysc=20° on the y-axis, and the number of dots per frame is 120000, the angular resolution is 0.1°. If the optical deflection angle θxsc=15° on the x-axis when the second optical path is used, the optical deflection angle θysc=20° on the y-axis, and the number of dots per frame is 120000, the angular resolution is 0.05°.

[0049] For this reason, assuming a situation in which the object detection device 1 of this embodiment is mounted on a vehicle and used as described above, for example, when the vehicle speed is fast, it is desired to be able to detect objects farther away but the detection range may be narrow, so it is preferable to use the second optical path with a narrow angle of view and high angular resolution. On the other hand, when the vehicle speed is slow, it is preferable to have a wider detection range, so it is preferable to use the first optical path with a wide angle of view and low angular resolution. In this case, regardless of which optical path is used, the angle of view can be formed without any gaps on either side of the normal c of the MEMS mirror 22 as shown in each figure, so it is possible to prevent the occurrence of an undetectable area.

[0050] In other words, by configuring the first optical path and the second optical path to be switchable, it is possible to switch the angle of view between wide and narrow without any gaps. In contrast, if a configuration is used in which light from two light sources is incident on the MEMS mirror through only one optical path each without including a polarization variable element, a gap will be generated in the central region including the normal C in the angle of view within a certain range of small deflection angles, even if the wideness is adjusted by changing the deflection angle of the MEMS mirror.

[0051] 7(A) and 7(B), the optical deflection angle of the MEMS mirror 22 may be adjusted so that the angles of view formed by the laser light from the light sources 26a and 26b partially overlap in the region including the normal line c. In the figures, patterns are added to make each angle of view easy to understand.

[0052] 8 is a flowchart showing the operation procedure of the object detection device 1 when variably setting the angle of view according to the vehicle speed. Note that the order of the processes shown here can be changed as long as no contradiction or inconsistency occurs in the results of the information processing, and other processes not explicitly shown here can also be added.

[0053] When the vehicle starts by turning on the ignition of the vehicle, the measurement control unit 11 of the control unit 10 starts object detection in the low-speed mode, which is a measurement mode using the first optical path (step S11). Specifically, the measurement control unit 11 controls the polarization variable element driver 23 by sending a command to the polarization control unit 13, and operates each of the polarization variable elements 24a, 24b so as not to rotate the polarization direction of the laser light. In addition, the measurement control unit 11 controls the MEMS driver 21 by sending a command to the deflection control unit 12, and controls the optical deflection angle of the MEMS mirror 22 to θxsc1, which is a magnitude corresponding to the incident angle θ1. As a result, an angle of view using the first optical path is formed.

[0054] The measurement control unit 11 also acquires vehicle speed information (step S12), and if the vehicle speed is equal to or greater than a first threshold (e.g., 80km / h) (step S13; YES), switches the measurement mode to a high-speed mode, which is a measurement mode using the second optical path (step S14). Specifically, the measurement control unit 11 controls the polarization variable element driver 23 by sending a command to the polarization control unit 13, and operates each of the polarization variable elements 24a, 24b so as to rotate the polarization direction of the laser light by 90°. Also, the measurement control unit 11 controls the MEMS driver 21 by sending a command to the deflection control unit 12, and controls the optical deflection angle of the MEMS mirror 22 to θxsc2, which is a magnitude corresponding to the incident angle θ2. As a result, an angle of view using the second optical path is formed. Thereafter, the process returns to step S12.

[0055] Furthermore, if the vehicle speed is lower than the first threshold (step S13; NO) and is equal to or lower than a second threshold lower than the first threshold (step S15; YES), the measurement control unit 11 switches the measurement mode to a low-speed mode using the second optical path (step S16). Then, the process returns to step S13. On the other hand, if the vehicle speed is higher than the second threshold (step S15; NO), the process returns to step S12.

[0056] Here, the first threshold is the vehicle speed that is the standard for switching to the high-speed mode, and can be set to, for example, the above-mentioned 80 km / h. The second threshold is the vehicle speed that is the standard for switching to the low-speed mode, and can be set to, for example, the above-mentioned 60 km / h. The reason for setting two thresholds in this way is to prevent the measurement mode from switching more frequently than necessary.

[0057] According to the above-described embodiment, it is possible to provide an optical scanning device capable of greatly changing the angle of view during optical scanning, and an object detection device including the same.

[0058] In addition, the present disclosure is not limited to the contents of the above-mentioned embodiment, and various modifications can be made within the scope of the gist of the present disclosure. For example, in the above-mentioned embodiment, the object detection device is mounted on a vehicle to detect objects around the vehicle as an example of its use, but the use is not limited to this.

[0059] Furthermore, the optical configuration of the scanning light source unit 20 in the above-mentioned embodiment is just one example, and there are no particular limitations as long as the two optical paths can be variably set by combining each polarization variable element 24a, 24b and the beam splitters 40a, 40b, and the desired values ​​can be obtained as the angles of incidence θ1, θ2 on the MEMS mirror 22.

[0060] In the above embodiment, two light sources 26a and 26b are used, but three or more light sources can be used. For example, as in the modified embodiment shown in FIG. 9(A) and FIG. 9(B), the object detection device can be configured to include a first optical system including the light source 26a, mirrors 40a and 43a, a polarization variable element 24a (not shown), and a polarization beam splitter 40a, a second optical system including the light source 26b, mirrors 40b and 43b, a polarization variable element 24b (not shown), and a polarization beam splitter 40b, and a third optical system including a light source 50 and a mirror 51. In the object detection device of the modified embodiment shown in the figure, the laser light emitted from the light source 50 is reflected by the mirror 51 and enters the MEMS mirror 22, and is scanned by the MEMS mirror 22. In the third optical system, no polarization variable element or polarization beam splitter is used, and the optical path is fixed. As a result, an angle of view FOV3 is formed in an area including the normal c at the reference position of the MEMS mirror 22. In addition, the angle of view FOV1 by the first optical system is formed above the normal line c in the drawing, and the angle of view by the second optical system is formed below the normal line c in the drawing. In the illustrated example, the angles of view FOV1, FOV2, and FOV3 as a whole form a sector symmetrical with respect to the normal line c.

[0061] In addition, as in the modified embodiment shown in Figure 10 (A) and Figure 10 (B), either the first optical system or the second optical system may be omitted. In the illustrated example, the first optical system is omitted and the second optical system and the third optical system are combined, but the first optical system and the third optical system may be combined.

[0062] The present disclosure has the following features. (Appendix 1) An optical scanning device used in a device that detects an object by irradiating light and receiving reflected light, A deflector; At least one light source; a polarization variable element that is disposed so that light emitted from the light source is incident thereon and that emits a first emitted light mainly including a first light in a first polarization state or a second emitted light mainly including a second light in a second polarization state different from the first polarization state; A branching element that branches the first light and the second light into light traveling in different directions; an optical system that causes the first light branched by the branching element to be incident on the deflector at a first angle and causes the second light branched by the branching element to be incident on the deflector at a second angle different from the first angle; An optical scanning device comprising: (Appendix 2) the light emitted from the light source is in the first polarization state; the polarization variable element emits the first light by transmitting the light emitted from the light source without rotating the polarization direction of the light, and emits the second light by rotating the polarization direction of the light emitted from the light source by a predetermined angle. 2. The optical scanning device of claim 1. (Appendix 3) The polarization direction of the first light and the polarization direction of the second light are different by 90°. 3. The optical scanning device according to claim 2. (Appendix 4) The splitting element is a polarizing beam splitter. 4. The optical scanning device according to claim 3. (Appendix 5) a first driver for driving the light source; a second driver for driving the deflector; A third driver that drives the polarization variable element; 5. The optical scanning device according to claim 1, further comprising: (Appendix 6) An optical scanning device used in a device that detects an object by irradiating light and receiving reflected light, A deflector; A first light source and a second light source; a first polarization variable element that is disposed so that light emitted from the first light source is incident thereon and that emits a first emitted light mainly consisting of a first light in a first polarization state or a second emitted light mainly consisting of a second light in a second polarization state different from the first polarization state; A first branching element that branches the first light and the second light into different traveling directions; a first optical system that causes the first light branched by the branching element to be incident on the deflector at a first angle and causes the second light branched by the branching element to be incident on the deflector at a second angle different from the first angle; a second polarization variable element that is disposed so that light emitted from the second light source is incident thereon and that emits third emitted light mainly including third light in a first polarization state or third emitted light mainly including fourth light in the second polarization state; A second branching element that branches the third light and the fourth light into different traveling directions; a second optical system that causes the third light branched by the second branching element to be incident on the deflector at a third angle and causes the fourth light branched by the branching element to be incident on the deflector at a fourth angle that is different from the third angle; An optical scanning device comprising: (Appendix 7) a first driver that drives the first light source and the second light source; a second driver for driving the deflector; a third driver that drives the first polarization variable element and the second polarization variable element; Including, the first polarization variable element and the second polarization variable element are controlled by the third driver, so that a first angle of view formed by the first light and the third light and a second angle of view formed by the second light and the fourth light are selectively used. 7. The optical scanning device according to claim 6. (Appendix 8) the first angle of view is greater than the second angle of view, In the first angle of view, an angle of view by the first light and an angle of view by the third light are continuously formed, In the second angle of view, an angle of view by the second light and an angle of view by the fourth light are continuously formed. 8. The optical scanning device according to claim 7. (Appendix 9) An optical scanning device according to any one of claims 1 to 8, a light receiving section that detects reflected light caused by irradiation light emitted from the optical scanning device and generates a light receiving signal corresponding to the intensity of the reflected light; a control unit that controls an operation of the optical scanning device and generates point cloud information based on the light receiving signal; 1. An object detection device comprising: (Appendix 10) a vehicle mounted sensor that emits the irradiated light to the periphery of the vehicle and generates the point cloud information based on the light receiving signal corresponding to the reflected light from an object in the periphery of the vehicle; 10. An object detection device as described in Supplementary Note 9. (Appendix 11) the control unit controls the polarization variable element of the optical scanning device to emit either the first light or the second light in accordance with a speed of the vehicle. 11. An object detection device as described in claim 10. (Appendix 12) An optical scanning device according to claim 8; a light receiving section that detects reflected light caused by irradiation light emitted from the optical scanning device and generates a light receiving signal corresponding to the intensity of the reflected light; a control unit that controls an operation of the optical scanning device and generates point cloud information based on the light receiving signal; Including, the optical scanning device is mounted on a vehicle and emits the irradiation light to the periphery of the vehicle; The light receiving unit detects the reflected light from an object around the vehicle and generates the light receiving signal, The control unit generates the point cloud information based on the light receiving signal corresponding to the light receiving signal, the control unit controls the optical scanning device to form the first angle of view at a first speed of the vehicle, and to form the second angle of view at a second speed that is faster than the first speed. Object detection device. [Explanation of symbols]

[0063] 1: object detection device, 10: control unit, 20: scanning light source unit (optical scanning device), 21: MEMS driver, 22: MEMS mirror, 23: polarization variable element driver, 24a, 24b: polarization variable element, 25: light source driver, 26a, 26b: light source, 30: light receiving unit, 40a, 40b: polarizing beam splitter, 41a, 41b, 42a, 42b, 43a, 43b: mirror

Claims

1. An optical scanning device used in a device that detects an object by irradiating light and receiving reflected light, A deflector; At least one light source; a polarization variable element that is disposed so that light emitted from the light source is incident thereon and that outputs a first output light mainly including a first light in a first polarization state or a second output light mainly including a second light in a second polarization state different from the first polarization state; A branching element that branches the first light and the second light into light traveling in different directions; an optical system that causes the first light branched by the branching element to be incident on the deflector at a first angle and causes the second light branched by the branching element to be incident on the deflector at a second angle different from the first angle; An optical scanning device comprising:

2. the light emitted from the light source is in the first polarization state; The polarization variable element emits the first light by transmitting the light emitted from the light source without rotating the polarization direction of the light, and emits the second light by rotating the polarization direction of the light emitted from the light source by a predetermined angle.

2. The optical scanning device according to claim 1.

3. The polarization direction of the first light and the polarization direction of the second light are different by 90°.

3. The optical scanning device according to claim 2.

4. The splitting element is a polarizing beam splitter.

4. The optical scanning device according to claim 3.

5. A first driver for driving the light source; a second driver for driving the deflector; A third driver that drives the polarization variable element; The optical scanning device of claim 1 .

6. An optical scanning device used in a device that detects an object by irradiating light and receiving reflected light, A deflector; A first light source and a second light source; a first polarization variable element that is disposed so that light emitted from the first light source is incident thereon and that emits a first emitted light mainly including a first light in a first polarization state or a second emitted light mainly including a second light in a second polarization state different from the first polarization state; A first branching element that branches the first light and the second light into different traveling directions; a first optical system that causes the first light branched by the branching element to be incident on the deflector at a first angle and causes the second light branched by the branching element to be incident on the deflector at a second angle different from the first angle; a second polarization variable element that is disposed so that light emitted from the second light source is incident thereon and that emits a third emitted light mainly including a third light in a first polarization state or a third emitted light mainly including a fourth light in the second polarization state; A second branching element that branches the third light and the fourth light into different traveling directions; a second optical system that causes the third light branched by the second branching element to be incident on the deflector at a third angle and causes the fourth light branched by the branching element to be incident on the deflector at a fourth angle that is different from the third angle; An optical scanning device comprising:

7. a first driver that drives the first light source and the second light source; a second driver for driving the deflector; a third driver that drives the first polarization variable element and the second polarization variable element; Including, The first polarization variable element and the second polarization variable element are controlled by the third driver, so that a first angle of view formed by the first light and the third light and a second angle of view formed by the second light and the fourth light are selectively used.

7. The optical scanning device according to claim 6.

8. the first angle of view is greater than the second angle of view, In the first angle of view, an angle of view by the first light and an angle of view by the third light are continuously formed, In the second angle of view, an angle of view by the second light and an angle of view by the fourth light are continuously formed.

8. An optical scanning device according to claim 7.

9. An optical scanning device according to claim 1 or 6; a light receiving section that detects reflected light caused by irradiation light emitted from the optical scanning device and generates a light receiving signal corresponding to the intensity of the reflected light; a control unit that controls an operation of the optical scanning device and generates point cloud information based on the light receiving signal; 1. An object detection device comprising:

10. a vehicle mounted sensor that emits the irradiated light to the periphery of the vehicle and generates the point cloud information based on the light receiving signal corresponding to the reflected light from an object in the periphery of the vehicle; The object detection device according to claim 9 .

11. the control unit controls the polarization variable element of the optical scanning device to emit either the first light or the second light in accordance with a speed of the vehicle. The object detection device according to claim 10.

12. An optical scanning device according to claim 8; a light receiving section that detects reflected light caused by irradiation light emitted from the optical scanning device and generates a light receiving signal corresponding to the intensity of the reflected light; a control unit that controls an operation of the optical scanning device and generates point cloud information based on the light receiving signal; Including, the optical scanning device is mounted on a vehicle and emits the irradiation light to the periphery of the vehicle; The light receiving unit detects the reflected light from an object around the vehicle and generates the light receiving signal, The control unit generates the point cloud information based on the light receiving signal corresponding to the light receiving signal, the control unit controls the optical scanning device to form the first angle of view at a first speed of the vehicle, and to form the second angle of view at a second speed that is faster than the first speed. Object detection device.

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