Laser irradiation device, laser irradiation system, object detection apparatus, and ranging apparatus

Abstract

To provide a laser irradiation device capable of two-dimensionally scanning a laser beam with a simple mechanism and suppressing a synchronization shift between X scanning and Y scanning.SOLUTION: A laser irradiation device comprises a laser light source and a two-dimensional deflector. The two-dimensional deflector includes: a base body rotatable about a rotation axis; a first reflection surface disposed on the base body along the circumference of a first radius; a second reflection surface disposed on the base body along the circumference of a second radius; and a light guide portion for guiding a laser beam reflected by the first reflection surface to the second reflection surface. The first reflection surface is configured so that a tilt angle with respect to the rotation axis changes along the circumference of the first radius, and a tilt angle of the first reflection surface is configured to deflect the laser beam in a first direction recursively. The second reflection surface is configured so that a tilt angle with respect to the rotation axis changes along the circumference of the second radius, and a tilt angle of the second reflection surface is configured to deflect the laser beam in a second direction recursively.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laser irradiation device that scans a laser beam two-dimensionally. [Background technology]

[0002] In recent years, laser scanning devices that scan a laser beam two-dimensionally have been applied in various fields, such as object detection, distance measurement systems, image displays, 3D scanners, etc. To scan a laser beam two-dimensionally, a horizontal scanning mechanism and a vertical scanning mechanism (or an X scanning mechanism and a Y scanning mechanism) are used to scan the laser beam.

[0003] Patent Document 1 discloses a projection display device that includes a laser light source, an optical acoustic modulator that optically modulates the laser light in accordance with a video signal, a polygonal mirror that horizontally scans the modulated laser light, and a galvanometer mirror that vertically scans the modulated laser light.

[0004] Patent Document 2 discloses a laser irradiation device that has a movable plate that oscillates in the X direction and a movable plate that oscillates in the Y direction, matches the resonance frequencies of both movable plates, and detects and compensates for a phase difference. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-180759 [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-20873 Summary of the Invention [Problem to be solved by the invention]

[0006] The projection display device described in Patent Document 1 is equipped with an optical scanning means that combines a polygonal mirror for horizontal scanning and a galvanometer mirror for vertical scanning, but because it is necessary to provide a drive device for each of the polygonal mirror and the galvanometer mirror, the drive system becomes large. Also, if the drive timing of the polygonal mirror and the galvanometer mirror is not adjusted (synchronized), accurate scanning will not be possible.

[0007] In the laser irradiation device described in Patent Document 2, it is necessary to provide a driving device for each of the movable plates that oscillate in the X direction and the Y direction, and furthermore, complex control is required.

[0008] Meanwhile, distance measurement and object recognition methods using Lidar (Light Detection and Ranging) are being studied for autonomous driving systems and driver assistance systems for automobiles and other moving objects. In these and other fields, there has been a demand for a compact laser irradiation device that can scan a laser beam two-dimensionally with a simple mechanism, suppresses synchronization errors between the X and Y scans, and is also capable of detecting the movement of the laser beam. [Means for solving the problem]

[0009] One aspect of the present invention is a laser irradiation device comprising a laser light source and a two-dimensional deflector that two-dimensionally deflects and scans a laser beam output by the laser light source in a first direction and a second direction, the two-dimensional deflector comprising: a base body that can rotate around a rotation axis; a first reflecting surface that is arranged on the base body along a circumference of a first radius centered on the rotation axis; a second reflecting surface that is arranged on the base body along a circumference of a second radius centered on the rotation axis; and a light guiding unit that guides the laser beam reflected by the first reflecting surface to the second reflecting surface, wherein the first reflecting surface is the inclination angle of the first reflecting surface relative to the rotation axis is configured to change along the circumference of the first radius, and the inclination angle of the first reflecting surface is configured so that when the base is continuously rotated, the laser beam is recursively deflected in the first direction; and the inclination angle of the second reflecting surface relative to the rotation axis is configured to change along the circumference of the second radius, and the inclination angle of the second reflecting surface is configured so that when the base is continuously rotated, the laser beam is recursively deflected in the second direction. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a compact laser irradiation device that can perform two-dimensional scanning with a laser beam using a simple mechanism, can suppress missynchronization between X-scanning and Y-scanning. [Brief explanation of the drawings]

[0011] [Figure 1] 1A is a schematic perspective view showing the schematic configuration of a scanning optical system of a laser irradiation device according to Embodiment 1. FIG. 1B is a plan view of a two-dimensional deflector. [Figure 2] A perspective view of a two-dimensional deflector. [Figure 3] 1A is a cross-sectional view of the laser irradiation device according to the first embodiment taken along a radius R1, and FIG. 1B is a cross-sectional view of the laser irradiation device according to the first embodiment taken along a radius R2. [Figure 4](a) A diagram showing the inclination of the reflecting surface 213 in one section (angle coordinates 0° to 45°) and the reflection direction of the laser beam. (b) A schematic diagram showing that the inclination of the reflecting surface 213 is repeated in the same way in each section (i = 1 to 8). [Figure 5] 1A is a schematic diagram showing the relationship between the tilt of the reflecting surface 214 and the reflection direction of the laser beam in the angle coordinate range of 0° to 360°, and FIG. 1B is a schematic diagram showing that the tilt of the reflecting surface 214 changes continuously and linearly. [Figure 6] (a) A schematic diagram of a light guide section 300a in which reflecting mirrors 301 to 304 are individually installed. (b) A schematic diagram of a light guide section 300b which is an integrated prism with an internal total reflection surface. [Figure 7] 1A is a diagram showing the range in which the laser beam is deflected and scanned by the reflecting surface 213. FIG. 1B is a diagram showing the range in which the laser beam is deflected and scanned by the reflecting surface 214. FIG. [Figure 8] FIG. 10 is a perspective view of a two-dimensional deflector provided in the irradiation device according to the second embodiment. [Figure 9] 10(a) is a schematic diagram showing the relationship between the inclination of the reflecting surface 214a in the angle coordinates of 0° to 360° and the reflection direction of the laser beam, and FIG. 10(b) is a schematic diagram showing that the inclination of the reflecting surface 214a changes stepwise. [Figure 10] 10(a) is a cross-sectional view of the laser irradiation device according to embodiment 3 taken along a radius R1, and FIG. 10(b) is a schematic diagram showing how the irradiation position changes on a reflecting surface 214. FIG. [Figure 11] (a) A diagram showing an example in which a front lens 103 of a conjugate relay lens is arranged between an irradiation position P1 and a reflecting mirror 301 in the third embodiment. (b) A diagram showing an example in which a rear lens 104 of a conjugate relay lens is arranged between a reflecting mirror 304 and an irradiation position P2 in the third embodiment. [Figure 12] FIG. 10 is a schematic diagram showing a part of a laser irradiation system according to a fourth embodiment. [Figure 13] (a) A diagram showing a case in which a free-form surface mirror 301A is arranged as the reflecting mirror located closest to the reflecting surface 213 in the fifth embodiment. (b) A diagram showing a case in which a free-form surface mirror 304A is arranged as the reflecting mirror located closest to the reflecting surface 214 in the fifth embodiment. [Figure 14] 10(a) is a diagram showing the shape of a free-form surface mirror used in embodiment 5. FIG. 10(b) is a diagram showing the twist of the surface of the free-form surface mirror used in embodiment 5. [Figure 15] 13A is a diagram showing an example in which the irradiation spot is deformed from a perfect circle, and FIG. 13B is a diagram showing an example in which the shape of the irradiation spot is improved in the fifth embodiment. [Figure 16] (a) A diagram showing how a laser beam is guided from irradiation position P1 to irradiation position P2 using three reflective surfaces in embodiment 6. (b) A diagram showing how a laser beam is guided from irradiation position P1 to irradiation position P2 using three reflective surfaces in embodiment 6. [Figure 17] FIG. 13 is a block diagram for explaining the basic configuration of an object detection device according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] With reference to the drawings, a laser irradiation device and the like according to an embodiment of the present invention will be described. Note that the embodiments shown below are merely examples, and those skilled in the art can appropriately modify the detailed configurations, for example, without departing from the spirit of the present invention. In the drawings referred to in the following description of the embodiments and examples, elements denoted by the same reference numerals have the same functions unless otherwise noted. When multiple identical elements are arranged in a drawing, the assignment of the reference numerals and their explanations may be omitted.

[0013] Furthermore, since the drawings may be expressed schematically for the convenience of illustration and explanation, the shapes, sizes, arrangements, etc. of elements shown in the drawings may not strictly correspond to the actual objects. For example, even if a single lens is depicted in the drawings, it may be composed of multiple lenses unless otherwise specified.

[0014] [Embodiment 1] 1(a) is a schematic perspective view showing a schematic configuration of a scanning optical system of a laser irradiation device 100 according to embodiment 1. For ease of explanation, the drawing omits mechanical mechanisms for installing optical elements, a housing, electrical wiring, and the like.

[0015] The laser irradiation device 100 can output a laser beam output from a laser light source 101 by two-dimensionally scanning it, such as in a so-called raster scan. In FIG. 1(a), a virtual irradiation surface IRP is shown. The laser beam is deflected from a start point to an end point along the X direction on a scanning line SC1, and then deflected from a start point to an end point along the X direction on a scanning line SC2, which has a different position in the Z direction. Similarly, the laser beam is deflected from a start point to an end point along the X direction on scanning lines SC3, SC4, ..., SC8 in this order, and then returns to scanning line SC1, and the same scanning procedure can be repeated recursively. In other words, irradiation of one frame consisting of scanning lines SC1 to SC8 can be repeatedly performed.

[0016] For convenience of explanation and illustration, eight scanning lines, scanning lines SC1 to SC8, are shown, but the number of scanning lines constituting the irradiation of one frame and the scanning angles in the X and Y directions can be set appropriately depending on the application of the laser irradiation device 100, such as object detection, ranging system, image display, 3D scanner, etc. The direction of the scanning lines SC does not necessarily have to be horizontal (parallel to the X direction) and can be changed depending on the application; for example, in the case of LiDAR (Light Detection And Ranging) applications, the laser irradiation device 100 may be configured so that the direction of the scanning lines SC is vertical (parallel to the Z direction).

[0017] For ease of explanation, the XZ plane defined by the X-axis and Z-axis is used as an example of a virtual irradiated surface IRP, but the object, position, and direction irradiated with the deflected and scanned laser beam are not limited to the example shown in the figure.

[0018] [Overall configuration] As shown in FIG. 1( a ), the laser irradiation device 100 includes a laser light source 101 , a two-dimensional deflector 211 , and reflecting mirrors 301 to 304 .

[0019] The laser light source 101 is a light-emitting element having a wavelength and output intensity according to the application. For example, in the case of LiDAR applications, a laser diode in the invisible range such as infrared is preferably used, but is not limited to this. The laser light source 101 may be equipped with a collimating lens (not shown). The laser light source 101 may emit continuous light or pulsed light depending on the application of the laser irradiation device 100.

[0020] The two-dimensional deflector 211 is a disk-shaped member that can rotate around a rotation axis MX. The laser beam output by the laser light source 101 is irradiated onto an irradiation position P1 (first irradiation position) on a reflecting surface 213 (first reflecting surface) on the two-dimensional deflector 211. The laser beam DFX reflected by the reflecting surface 213 is reflected sequentially by a reflecting mirror 301, a reflecting mirror 302, a reflecting mirror 303, and a reflecting mirror 304, and is irradiated onto an irradiation position P2 (second irradiation position) on a reflecting surface 214 (second reflecting surface). The laser beam DFXY reflected by the reflecting surface 214 is output from the laser irradiation device 100 as a two-dimensionally deflected output beam.

[0021] A line connecting an irradiation position P1 where the laser beam irradiates the reflecting surface 213 and the rotation axis MX, which is the rotation center of the two-dimensional deflector 211, is defined as radius R1, and a radius perpendicular to radius R1 (a line passing through the rotation axis MX and perpendicular to radius R1) is defined as radius R2. As will be described later, irradiation position P2 where the laser beam deflected and scanned by the reflecting surface 213 irradiates the reflecting surface 214 moves slightly back and forth in the X direction around the position where radius R2 and the reflecting surface 214 intersect. Although radius R2, which is located at the center of the reciprocating movement, is perpendicular to radius R1, the line connecting irradiation position P2 and the rotation axis MX moves slightly over time, so strictly speaking, it cannot be said to always be perpendicular to radius R1. However, it can be said that the line connecting irradiation position P2 and the rotation axis MX is approximately perpendicular to radius R1. This will be described again with reference to FIG. 10(b) in embodiment 3.

[0022] Fig. 1(b) shows a plan view of the two-dimensional deflector 211, and Fig. 2 shows a perspective view of the two-dimensional deflector 211. Fig. 3(a) shows a cross-sectional view of the laser irradiation device 100 taken along radius R1, and Fig. 3(b) shows a cross-sectional view of the laser irradiation device 100 taken along radius R2. As shown in Figs. 3(a) and 3(b), the laser irradiation device 100 includes a rotatable, disk-shaped two-dimensional deflector 211 and a motor 212 that rotates the two-dimensional deflector 211 about a rotation axis MX. Reflecting surfaces 213 and 214, which are strip-shaped reflecting surfaces, are provided on the main surface of the disk-shaped two-dimensional deflector 211 along the circumference.

[0023] Regarding the manufacturing method of two-dimensional deflector 211, the disk-shaped base provided with band-shaped reflecting surfaces 213 and 214 along the circumference can be manufactured at low cost by processing a metal base material using, for example, a press extrusion method. Alternatively, the disk-shaped base may be manufactured by cutting and polishing a metal base material, or the base may be manufactured by molding using a mold with glass or resin as a molding material, and a metal film may be formed on the portions that will become the reflecting surfaces by vapor deposition or plating.

[0024] The two-dimensional deflector 211 performs deflection scanning of one frame by rotating once around the rotation axis MX. Here, to identify the position within the reflecting surface, angle coordinates are set counterclockwise around the rotation axis MX as shown in Fig. 2 (0°, 90°, 180°, and 270° are shown in the figure).

[0025] (X-direction scanning) The reflecting surface 213 is a reflecting surface that allows the laser beam to be deflected and scanned in the X direction on the irradiated surface IRP (FIG. 1(a)). The strip-shaped reflecting surface 213 is twisted so that the angle with respect to the rotation axis MX changes depending on the position on the angular coordinate system. For example, in one frame, when scanning is performed eight times in the X direction along scanning lines SC1 to SC8, the reflecting surface 213 is equally divided into eight sections (if each section is designated by the symbol i to distinguish it, i = 1 to 8). Each section has a width of 45° in the angular coordinate system centered on the rotation axis MX. In other words, when deflection scanning is performed in the X direction along M scanning lines (M is an integer of 2 or greater), the reflecting surface 213 has M sections (M is an integer of 2 or greater) that divide the circumference equally, and the inclination angle of the reflecting surface changes in the same way in each section.

[0026] Fig. 4(a) shows the inclination of the reflecting surface 213 in one section (angle coordinate 0° to 45°) and the reflection direction of the laser beam. Note that the axis BX shown in the figure is an axis that is parallel to the rotation axis MX and passes through the reflecting surface 213. Fig. 4(b) also shows a schematic diagram showing that the inclination of the reflecting surface 213 is structured so that it is repeated in the same way in each section (i = 1 to 8).

[0027] 4(a) and 4(b), the positions of the reflecting surfaces are positions defined by the angular coordinates explained in Fig. 2. The tilt angles of the reflecting surfaces are the tilt angles of the reflecting surfaces when the main surface of the disk-shaped two-dimensional deflector 211 (i.e., the surface perpendicular to the axis BX) is used as the reference.

[0028] As shown in Fig. 4(b), the reflecting surface is configured so that the inclination angle of the reflecting surface changes linearly with position within each section of reflecting surface 213. Because the sections are arranged adjacent to each other, as shown in Fig. 4(b), the inclination angle of the reflecting surface is discontinuous at the boundaries between sections, i.e., at locations where the position coordinates are multiples of 45°.

[0029] When the two-dimensional deflector 211 is rotated in the R direction shown in FIG. 1(a) by the motor 212, the angular coordinate of the part irradiated with the laser beam at the irradiation position P1 changes continuously as follows: 0° → 90° → 180° → 360° (=0°) → 90°...

[0030] As shown in Figure 4(a), even if the reflecting surface 213 rotates around the rotation axis MX and the area irradiated by the laser beam changes, the incident beam always enters the reflecting surface 213 at an angle β with respect to the axis BX. Meanwhile, within each section, the inclination angle of the reflecting surface changes within a range from -α to +α depending on the position of the reflecting surface. Therefore, as shown in Figure 4(a), the direction of the laser beam reflected by the reflecting surface 213 changes within an angle range of 4α from (β-2 × α) to (β+2 × α) with the axis BX as the reference. In other words, when the optical surface (reflecting surface) is continuously rotated at a constant speed, the inclination angle is configured so that the laser beam is recursively deflected in a constant direction at a constant deflection speed.

[0031] FIG. 7(a) shows the range in which the laser beam is deflected and scanned by the reflecting surface 213. When the reflecting surface 213 is continuously rotated in the R direction shown in FIG. 1(a), the laser beam reflected by the reflecting surface 213 is continuously deflected (scanned) from RD1 to RD2 in FIG. 7(a). When the reflecting surface 213 reaches RD2, the laser beam instantly returns to RD1 and is deflected (scanned) again toward RD2. Since the laser beam is deflected and scanned from RD1 to RD2 in each of the eight sections, one rotation of the two-dimensional deflector 211 results in eight deflection scans from RD1 to RD2. In other words, as shown in FIG. 4(a), each section of the reflecting surface 213 can deflect and scan the emitted beam within an angular range from RD1 ((β-2×α) with respect to the axis BX) to RD2 ((β+2×α) with respect to the axis BX).

[0032] Furthermore, if the reflecting surface 213 is rotated in the opposite direction to the R direction, the emitted beam will be continuously deflected (scanned) from RD2 to RD1 in Figure 7(a), and when it reaches RD1, it will instantly return to RD2 and be deflected (scanned) again towards RD1.

[0033] In this way, the two-dimensional deflector 211 can recursively deflect and scan the laser beam at a constant speed in the X direction on the irradiated surface IRP (FIG. 1(a)) using a simple driving method of continuously rotating the rotating body at a constant speed.

[0034] (Light guide section from reflecting surface 213 to reflecting surface 214) 1(a), laser beam DFX reflected (deflected and scanned) by reflecting surface 213 at irradiation position P1 is reflected in turn by reflecting mirror 301, reflecting mirror 302, reflecting mirror 303, and reflecting mirror 304, and is irradiated onto irradiation position P2 of reflecting surface 214. In other words, reflecting mirrors 301 to 304 form a light guiding section for guiding the laser beam reflected by reflecting surface 213 to reflecting surface 214.

[0035] Laser beam DFX, which is guided to irradiation position P2 via reflecting mirrors 301 to 304, is periodically deflected and scanned in the X direction by reflecting surface 213. In FIG. 1(a), to facilitate understanding of the behavior of the laser beam, the movement direction of laser beam DFX accompanying deflection scanning is indicated by an arrow on each of reflecting mirrors 301 to 304, which are arranged as crossed mirrors. Note that, because the relative positions of laser light source 101 and two-dimensional deflector 211 are fixed, irradiation position P1 is always located on radius R1 and remains stationary. Meanwhile, irradiation position P2, which irradiates reflecting surface 214, periodically moves slightly along the X direction around radius R2, which is perpendicular to radius R1.

[0036] As a method of configuring the light guide section, as shown schematically in FIG. 6(a), reflecting mirrors 301 to 304 may be individually installed to configure light guide section 300a that guides the laser beam from reflecting surface 213 to reflecting surface 214.

[0037] Alternatively, as shown schematically in Figure 6(b), a light-guiding section 300b that guides the laser beam from reflecting surface 213 to reflecting surface 214 may be formed by forming an integrated prism with four internal total reflection surfaces using an optical material such as glass.

[0038] (Z-direction scanning) The reflecting surface 214 is a reflecting surface for deflecting and scanning the laser beam in the Z direction on a virtual irradiated surface IRP (FIG. 1(a)). The strip-shaped reflecting surface 214 is twisted so that the angle with respect to the rotation axis MX changes depending on the position on the angular coordinate. Taking the case where the laser beam is scanned once in the Z direction in one frame as an example, the inclination of the reflecting surface 214 is configured to change continuously (for example, monotonically increase) between the angular coordinates of 0° and 360° (one rotation).

[0039] Fig. 5(a) is a schematic diagram showing the relationship between the inclination of reflecting surface 214 in the angular coordinate range of 0° to 360° and the reflection direction of the laser beam. Note that the axis AX shown in the figure is an axis that is parallel to the rotation axis MX and passes through reflecting surface 214. Fig. 5(b) is a schematic diagram illustrating that the inclination of reflecting surface 214 changes continuously and linearly.

[0040] 5(a) and 5(b), the positions of the reflecting surfaces are positions defined by the angular coordinates described in FIG. 2. The tilt angles of the reflecting surfaces are the tilt angles of the reflecting surfaces when the main surface of the disk-shaped two-dimensional deflector 211 (i.e., the surface perpendicular to the axis AX) is used as a reference. As shown in FIGS. 2 and 5(b), the tilt angles of the reflecting surfaces are discontinuous at locations where the angular coordinate is 0° (=360°).

[0041] When the two-dimensional deflector 211 is rotated in the R direction in FIG. 1(a) by the motor 212, the angular coordinate of the part irradiated with the laser beam at the irradiation position P2 changes continuously as follows: 0° → 90° → 180° → 360° (=0°) → 90°...

[0042] Even if the reflecting surface 214 rotates around the rotation axis MX and the area irradiated with the laser beam changes, the incident beam always strikes the reflecting surface 214 at an angle γ with respect to the axis AX, as shown in FIG. 5(a).

[0043] Meanwhile, the tilt angle of the reflecting surface 214 varies within a range of -δ to +δ depending on the position of the reflecting surface. Therefore, as shown in Fig. 5(a), the direction of the laser beam reflected by the reflecting surface 214 varies within an angular range of 4δ, from (γ-2 × δ) to (γ+2 × δ), with the axis AX as the reference. In other words, the tilt angle is configured so that when the optical surface (reflecting surface) is continuously rotated at a constant speed, the laser beam is recursively deflected in a constant direction at a constant deflection speed.

[0044] FIG. 7(b) shows the range in which the laser beam is deflected and scanned by the reflecting surface 214. When the reflecting surface 214 is continuously rotated in the direction R shown in FIG. 1(a), the laser beam (outgoing beam) reflected by the reflecting surface 214 is continuously deflected (scanned) from RD3 to RD4 in FIG. 7(b), and when it reaches RD4, it instantly returns to RD3 and is deflected (scanned) again toward RD4. When the two-dimensional deflector 211 is rotated once, one deflection scan is performed from RD3 to RD4. In other words, as shown in FIG. 7(b), the reflecting surface 214 can deflect and scan the outgoing beam within an angular range from RD3 ((γ-2×δ) with respect to the axis AX) to RD4 ((γ+2×δ) with respect to the axis AX).

[0045] Furthermore, if the reflecting surface 214 is rotated in the opposite direction to the R direction, the emitted beam will be continuously deflected (scanned) from RD4 to RD3 in Figure 7(b), and when it reaches RD3, it will instantly return to RD4 and be deflected (scanned) again towards RD3.

[0046] In this way, the two-dimensional deflector 211 can recursively deflect and scan the laser beam at a constant speed in the Z direction on the irradiated surface IRP (Figure 1(a)) using a simple driving method of continuously rotating the rotating body at a constant speed.

[0047] The laser beam (emitted beam) reflected by the reflecting surface 214 is subjected to a two-dimensional deflection scan as shown on the irradiated surface IRP in FIG. 1(a) since the deflection scan by the reflecting surface 213 and the deflection scan by the reflecting surface 214 are superimposed on each other.

[0048] As described above, according to this embodiment, a laser beam can be two-dimensionally scanned and irradiated using a simple mechanism. The reflecting surface 213 for X-scanning and the reflecting surface 214 for Y-scanning (Z-scanning on the irradiated surface IRP) are fixed on a rotatable, disk-shaped two-dimensional deflector 211, and their relative positional relationship does not fluctuate. Therefore, unlike the case where two galvanometer scanners are used, it is possible to easily prevent misalignment of the X-scanning and the Y-scanning. Furthermore, compared to the case where two galvanometer scanners are used, the laser irradiation device can be configured more compactly. The laser irradiation device according to this embodiment can be applied to a wide range of fields, such as Lidar (Light Detection and Ranging) for autonomous driving systems and driver assistance systems for automobiles and other mobile objects, as well as distance measurement systems, object recognition systems, and monitoring systems.

[0049] [Embodiment 2] A laser irradiation device according to embodiment 2 will be described. Figures and descriptions of matters common to embodiment 1 will be simplified or omitted. This embodiment is common to embodiment 1 in that a reflective surface for X scanning and a reflective surface for Y scanning (Z scanning on the irradiated surface IRP) are fixed to a rotatable, disk-shaped two-dimensional deflector. However, this embodiment differs from embodiment 1 in the configuration of the reflective surface for Y scanning.

[0050] Fig. 8 shows a perspective view of a two-dimensional deflector 211A provided in the irradiation device according to this embodiment. Fig. 8 is a drawing corresponding to Fig. 2 referred to in the description of the first embodiment. Like the two-dimensional deflector 211 of the first embodiment, the two-dimensional deflector 211A according to this embodiment also rotates once around the rotation axis MX for scanning one frame. Here, in order to identify a position within the reflection surface, angle coordinates are set counterclockwise around the rotation axis MX as shown in Fig. 8 (0°, 90°, 180°, and 270° are shown in the figure).

[0051] (X-direction scanning) The reflecting surface 213 is a reflecting surface for deflecting and scanning the laser beam in the X direction on the irradiated surface IRP (FIG. 1(a)). The X direction scanning is the same as that of the two-dimensional deflector 211 of the first embodiment described with reference to FIGS. 4(a), 4(b), etc., and therefore a description thereof will be omitted.

[0052] (Light guide section from reflecting surface 213 to reflecting surface 214a) Since this is the same as in the first embodiment, the explanation will be omitted.

[0053] (Z-direction scanning) The reflecting surface 214a is a reflecting surface for deflecting and scanning the laser beam in the Z direction on a virtual irradiation surface IRP (FIG. 1(a)). The strip-shaped reflecting surface 214a is twisted so that the angle with respect to the rotation axis MX changes in stages (stepwise) depending on the position on the angular coordinate. Taking the case where the laser beam scans once in the Z direction in one frame as an example, the inclination of the reflecting surface 214a is configured to change in stages (stepwise) between the angular coordinates of 0° and 360° (one rotation).

[0054] In the first embodiment, as described with reference to Fig. 5(b), the inclination of the reflecting surface 214 is configured to change continuously between angular coordinates of 0° and 360° (one rotation). Therefore, the inclination angle of the reflecting surface 214 changes continuously even while the two-dimensional deflector 211 is rotated and scanning is performed in the X direction along the scanning lines (scanning lines SC1 to SC8) corresponding to the sections of the reflecting surface 213. For this reason, on the illuminated surface IRP shown in Fig. 1(a), the scanning lines (scanning lines SC1 to SC8) are not completely parallel to the X direction (horizontal direction).

[0055] In this embodiment, while scanning one scanning line, the trajectory of the laser beam does not move in the Z direction on the irradiated surface IRP, that is, each scanning line (scanning lines SC1 to SC8) is configured to be parallel to the X direction (horizontal direction).

[0056] Fig. 9(a) is a schematic diagram showing the relationship between the inclination of reflecting surface 214a in the angular coordinate range of 0° to 360° and the reflection direction of the laser beam. Note that the axis AX shown in the figure is an axis that is parallel to the rotation axis MX and passes through reflecting surface 214a. Fig. 9(b) is a schematic diagram showing that the inclination of reflecting surface 214a changes in stages (stepwise).

[0057] 9(a) and 9(b), the positions of the reflecting surfaces are positions defined by the angle coordinates explained in Fig. 8. The tilt angles of the reflecting surfaces are the tilt angles of the reflecting surfaces when the main surface of the disk-shaped two-dimensional deflector 211A (i.e., the surface perpendicular to the axis AX) is used as a reference.

[0058] In this embodiment, reflecting surface 214a is divided into equal sections (e.g., i=8) that are the same as those of reflecting surface 213. Reflecting surface 213 and reflecting surface 214a are divided into sections using the same angular coordinates. As shown in Figures 8 and 9(b), the inclination angle of the reflecting surface is discontinuous at the boundaries of the sections.

[0059] When the two-dimensional deflector 211A is rotated in the R direction in FIG. 1(a) by the motor 212, the angular coordinate of the area irradiated with the laser beam at the irradiation position P2 changes continuously as follows: 0° → 90° → 180° → 360° (=0°) → 90°...

[0060] Even if the reflecting surface 214a rotates around the rotation axis MX and the area irradiated with the laser beam changes, the incident beam always strikes the reflecting surface 214a at an angle γ with respect to the axis AX, as shown in FIG. 9(a).

[0061] Meanwhile, the tilt angle of reflecting surface 214a changes stepwise within the range of -δ to +δ depending on the position of the reflecting surface. Therefore, as shown in Fig. 9(a), the direction of the laser beam reflected by reflecting surface 214a changes within an angular range of 4δ from (γ - 2 × δ) to (γ + 2 × δ) with respect to axis AX. In other words, when the optical surface (reflecting surface) is continuously rotated at a constant speed, the tilt angle is configured so that the laser beam is deflected stepwise and recursively in a constant direction according to the switching of sections i = 1 to 8.

[0062] The range over which the laser beam is deflected is the same as that of the first embodiment described with reference to FIG. 7(b). When the reflecting surface 214 is continuously rotated in the R direction shown in FIG. 1(a), the emitted beam is deflected (scanned) stepwise from RD3 to RD4 in FIG. 7(b). When the emitted beam reaches RD4, it instantly returns to RD3 and is deflected (scanned) again toward RD4. When the two-dimensional deflector 211A rotates once, one deflection scan is performed from RD3 to RD4. In other words, as shown in FIG. 7(b), the reflecting surface 214a can deflect and scan the emitted beam within an angular range from RD3 ((γ-2×δ) with respect to the axis AX) to RD4 ((γ+2×δ) with respect to the axis AX).

[0063] Furthermore, if the reflecting surface 214a is rotated in the opposite direction to the R direction, the emitted beam will be deflected (scanned) in stages from RD4 to RD3 in Figure 7(b), and when it reaches RD3, it will instantly return to RD4 and be deflected (scanned) again towards RD3.

[0064] In this way, the two-dimensional deflector 211A can deflect and scan the laser beam stepwise and recursively in the Z direction on the irradiated surface IRP (Figure 1(a)) using a simple driving method of continuously rotating the rotating body at a constant speed.

[0065] As described above, according to this embodiment, a laser beam can be two-dimensionally scanned and irradiated using a simple mechanism. The reflecting surface 213 for X-scanning and the reflecting surface 214a for Y-scanning (Z-scanning on the irradiated surface IRP) are fixed on a rotatable, disk-shaped two-dimensional deflector 211A, and their relative positional relationship does not fluctuate. Therefore, unlike the case where two galvanometer scanners are used, it is easy to prevent misalignment between the X-scanning and the Y-scanning. Furthermore, compared to the case where two galvanometer scanners are used, the laser irradiation device can be configured more compactly. Furthermore, compared to the first embodiment, the horizontality of each scan line (parallelism with respect to the X-axis) can be improved. The laser irradiation device of this embodiment can be applied to a wide range of fields, such as Lidar (Light Detection and Ranging) for autonomous driving systems and driver assistance systems for automobiles and other moving objects, as well as distance measurement systems, object recognition systems, and monitoring systems.

[0066] [Embodiment 3] A laser irradiation device according to embodiment 3 will be described. Illustrations and descriptions of matters common to embodiment 1 or embodiment 2 will be simplified or omitted. This embodiment is common to embodiment 1 and embodiment 2 in that a reflective surface for X scanning and a reflective surface for Y scanning are fixed to a rotatable, disk-shaped two-dimensional deflector.

[0067] In the first and second embodiments, as described with reference to FIG. 7(a), the laser beam is deflected and scanned by the reflecting surface 213 within an angular range from RD1 ((β-2×α) with respect to the axis BX) to RD2 ((β+2×α) with respect to the axis BX). FIG. 10(a) shows a partial cross-sectional view taken along the radius R1 of FIG. 1(a). FIG. 10(b) shows a schematic diagram of how the irradiation position changes on the reflecting surface 214.

[0068] Irradiation position P2 changes as the laser beam is deflected and scanned between RD1 and RD2 by reflecting surface 213. As shown in Figure 10(b), when the laser beam is positioned in the center between RD1 and RD2, irradiation position P2 is located on radius R2, but at other times irradiation position P2 is located slightly offset from radius R2. In other words, strictly speaking, the line connecting irradiation position P1 and rotation axis MX and the line connecting irradiation position P2 and rotation axis MX are not always perpendicular to each other, but rather are approximately perpendicular to each other.

[0069] In the first embodiment, the tilt angle of the reflecting surface 214 is discontinuous at the position of angular coordinate 0°, which is the start point of one frame (= angular coordinate 360°, which is the end point of one frame). In the second embodiment, the tilt angle of the reflecting surface 214a is discontinuous at the angular coordinate corresponding to the start point (= end point) of each scanning line, i.e., the angular coordinate of the boundary between the sections. In FIG. 10(b), the laser beam takes the trajectory of RD1 or RD2 when it is at the start point or end point of each scanning line, just before or just after the position where the tilt angle of the reflecting surface 214 is discontinuous is on the radius R2. As a result, the laser beam may be irradiated at a position shifted before or after the timing at which the laser light should be irradiated onto the boundary where the tilt angle is discontinuous, resulting in irregular scanning.

[0070] Therefore, in this embodiment, a conjugate relay lens is provided so that the irradiation position P1 and the irradiation position P2 are conjugate to each other. Specifically, as shown in FIG. 11(a), a front lens 103 of the conjugate relay lens is disposed between the irradiation position P1 and the reflecting mirror 301. Furthermore, as shown in FIG. 11(b), a rear lens 104 of the conjugate relay lens is disposed between the reflecting mirror 304 and the irradiation position P2. By providing a conjugate relay lens so that the irradiation position P1 and the irradiation position P2 are conjugate to each other, the amount of movement of the irradiation position P2 on the reflecting surface 214 is suppressed even if the light is deflected by the reflecting surface 213 (irradiation position P1). Therefore, irregular scanning can be suppressed on the virtual irradiated surface IRP (FIG. 1(a)).

[0071] [Embodiment 4] A laser irradiation system according to embodiment 4 will be described. Illustrations and descriptions of matters common to the embodiments already described will be simplified or omitted. This embodiment is common to the embodiments already described in that a reflective surface for X scanning and a reflective surface for Y scanning are fixed to a rotatable, disk-shaped two-dimensional deflector.

[0072] This embodiment is a laser irradiation system in which a projection lens is further attached to the laser irradiation device according to any of the above-described embodiments. Fig. 12 is a schematic diagram showing a part of the laser irradiation system. In this embodiment, a primary plane IM1 of a laser beam scanned by the laser irradiation device is projected onto a secondary plane IM2 using a projection lens 105. By making the focal length of the projection lens 105 variable, when the secondary plane IM2 is set as the target plane, the angle of view ω can be arbitrarily set according to the distance L.

[0073] [Embodiment 5] A laser irradiation device according to embodiment 5 will be described. Illustrations and descriptions of matters common to the embodiments already described will be simplified or omitted. This embodiment is common to the embodiments already described in that a reflective surface for X scanning and a reflective surface for Y scanning are fixed to a rotatable, disk-shaped two-dimensional deflector.

[0074] In this embodiment, a part of the reflecting mirror constituting the light guide section 300a shown in FIG. 6(a) is not a mirror with a flat reflecting surface, but a mirror (free-form mirror) with a reflecting surface of a free-form shape with a continuous amount of twist.

[0075] Specifically, as shown in FIG. 13(a), free-form surface mirror 301A is positioned as the reflecting mirror closest to reflecting surface 213, and as shown in FIG. 13(b), free-form surface mirror 304A is positioned as the reflecting mirror closest to reflecting surface 214. As shown in FIGS. 14(a) and 14(b), free-form surface mirror 301A has a reflecting surface in which a twist amount η is continuously given in the y coordinate with respect to a completely flat surface. When spot rotation occurs due to the twisted surfaces of reflecting surfaces 213 and 214, the spot shape of the laser beam can be corrected by using the free-form surface mirror. Note that the twist correction amount of free-form surface mirror 301A and free-form surface mirror 304A does not necessarily have to be linear.

[0076] When the spot shape of the laser beam on the irradiated surface IRP (FIG. 1(a)) deforms from a perfect circle as shown in FIG. 15(a), for example, this embodiment can improve the circularity of the spot shape as shown in FIG. 15(b). Any mirror located between the irradiation position P1 and the irradiation position P2 can be a free-form surface mirror. The free-form surface mirror may be configured with the internal total reflection surface of a prism as shown in FIG. 6(b).

[0077] [Embodiment 6] A laser irradiation device according to embodiment 6 will be described. Illustrations and descriptions of matters common to the already-described embodiments will be simplified or omitted. This embodiment is common to the already-described embodiments in that a reflective surface for X scanning and a reflective surface for Y scanning are fixed to a rotatable, disk-shaped two-dimensional deflector.

[0078] In the above-described embodiment, a light guide unit having four reflecting surfaces as shown in Figures 6(a) and 6(b) is used to guide the laser beam from irradiation position P1 to irradiation position P2, but the configuration of the light guide unit is not limited to this.

[0079] As shown in Figures 16(a) and 16(b), in this embodiment, a laser beam is guided from irradiation position P1 to irradiation position P2 by a light guide unit equipped with three reflecting surfaces: reflecting mirror 301B, reflecting mirror 302B, and reflecting mirror 303B. Reflecting mirror 301B is a mirror that reflects in the x direction, reflecting mirror 303B is a mirror that reflects in the y direction, and reflecting mirror 302B has reflection angles set in both the x and y directions. With this configuration, the reflected image is twisted by 90°, and the traveling direction of the laser beam is changed by 90°. By using three reflecting surfaces, the number of parts can be reduced. Note that some or all of the three reflecting surfaces may be configured as internal total reflection surfaces of a prism.

[0080] [Embodiment 7] An object detection device according to a seventh embodiment will be described. Illustrations and descriptions of matters common to the already-described embodiments will be simplified or omitted. This embodiment is common to the already-described embodiments in that a reflective surface for X scanning and a reflective surface for Y scanning are fixed to a rotatable, disk-shaped two-dimensional deflector.

[0081] This embodiment is an object detection device including a laser irradiation device or a laser irradiation system according to any of the above-described embodiments. Fig. 17 is a block diagram for explaining the basic configuration of an object detection device 400 according to this embodiment. The object detection device 400 includes a laser light source 101, a two-dimensional deflector 211, a controller 500, a light source control unit 501, a motor drive unit 502, a light receiving sensor unit 503, a data processing unit 504, and an I / O unit 505.

[0082] The controller 500 is a computer for controlling the operation of each part of the object detection device 400. The I / O unit 505 is an input / output unit that communicatively connects the object detection device 400 to an external device (for example, an external computer or storage device) or an external network.

[0083] The laser light source 101 is a laser light source that outputs a laser beam under the control of the light source control unit 501. For example, a laser diode in the invisible range such as infrared light is preferably used as the laser light source 101, but the present invention is not limited to this and may be a laser light source that outputs a laser beam in the visible range.

[0084] The two-dimensional deflector 211 is a two-dimensional deflector according to any of the above-described embodiments, and a motor 212 driven under the control of a motor driving unit 502 rotates the disk-shaped two-dimensional deflector 211, thereby two-dimensionally deflecting and scanning the laser beam emitted from the laser light source 101.

[0085] The laser light source 101, light source control unit 501, two-dimensional deflector 211, and motor drive unit 502, which operate under the control of the controller 500, constitute a laser irradiation device according to any of the above-described embodiments. Although not shown in Fig. 17, a projection lens 105 with a variable focal length may be provided as in embodiment 4 (Fig. 12), and the controller 500 may be configured to control the focal length of the projection lens 105.

[0086] The light receiving sensor unit 503 is an optical sensor that is sensitive to the wavelength band of the laser beam output by the laser light source 101. A CMOS image sensor or a CCD sensor is preferably used. The light receiving sensor unit 503 detects reflected light that is reflected back from an object when the laser beam emitted from the object detection device 400 while being deflected and scanned irradiates the object to be detected. The light receiving sensor unit 503 may be a TOF sensor (Time Of Flight Sensor) that measures the flight time of the pulsed laser light emitted from the laser light source 101, reflected by the object, and returned.

[0087] The data processing unit 504 calculates the position of the object to be detected based on the irradiation direction of the laser beam and information on the returned light detected by the light receiving sensor unit 503. The data processing unit 504 can calculate the irradiation direction of the laser beam, i.e., the direction of the object, based on drive information from the motor drive unit 502 that controls the rotation of the two-dimensional deflector 211. The data processing unit 504 can calculate the distance to the object based on the TOF information measured by the light receiving sensor unit 503. After calculating the object's position information, the data processing unit 504 transmits the calculation result (object detection information) to the controller 500 or to an external device of the object detection device 400 via the I / O unit 505. The external device of the object detection device 400 may be, for example, a computer for an automatic driving system or a driving assistance system for a mobile object such as an automobile.

[0088] According to this embodiment, a Lidar (Light Detection And Ranging) that can be applied to an object detection device or a distance measurement device can be configured compactly using a laser irradiation device in which synchronization error between X scanning and Y scanning is suppressed.

[0089] [Other embodiments] The present invention is not limited to the above-described embodiments, and many modifications are possible within the technical spirit of the present invention. For example, the above-described different embodiments and examples may be combined in whole or in part.

[0090] For example, in the above embodiment, when the two-dimensional deflector makes one rotation, the laser beam is deflected and scanned in sequence along the first to Mth scanning lines (M is an integer equal to or greater than 2) that extend along the X direction and are positioned differently in the Z direction, completing the irradiation of one frame. However, by changing the period of the angular coordinates at which the inclined surfaces of the reflecting surfaces 213 and 214 change in the above embodiment, the number of frames per rotation can be changed. For example, by halving the period of the angular coordinates at which the inclined surfaces change compared to the above embodiment, the two-dimensional deflector can be configured so that two frames are irradiated per rotation. In this way, the number of scanning frames corresponding to one rotation of the two-dimensional deflector can be set arbitrarily, and a laser irradiation device capable of high-speed frame scanning even with a low rotation speed, for example, can be configured.

[0091] The light guide section that guides the laser beam reflected by reflecting surface 213 to reflecting surface 214 may be configured to include three or more reflecting surfaces. The number of reflecting surfaces is not limited to three or four as exemplified in the embodiment. The reflecting surface may be a reflecting mirror or a total internal reflection surface of a prism, and the light guide section may be configured by combining a reflecting mirror and a prism. The light guide section may also include either or both of a reflecting surface with a free-form curved shape and a conjugate relay lens.

[0092] In the above embodiment, a two-dimensional deflector is exemplified in which the reflecting surface 213, where the laser beam is input from the laser light source, is located on the outer periphery side, and the reflecting surface 214, where the laser beam that has been two-dimensionally deflected and scanned is output, is located on the inner periphery side, but the outer periphery side and the inner periphery side may be reversed.

[0093] Two-dimensional deflector 211 may have reflecting surface 213 and reflecting surface 214 formed on a single substrate, or may be configured in other ways. For example, two-dimensional deflector 211 may be configured by forming reflecting surface 214 on a first substrate (a small-diameter disk), forming reflecting surface 213 on a second substrate (a large-diameter disk), and bonding and integrating the first substrate onto the second substrate.

[0094] This specification discloses at least the following: [Item 1] a laser light source; a two-dimensional deflector that two-dimensionally deflects and scans the laser beam output from the laser light source in a first direction and a second direction, The two-dimensional deflector is a base body rotatable about a rotation axis; a first reflecting surface disposed on the base along a circumference of a first radius centered on the rotation axis; a second reflecting surface disposed on the base along a circumference of a second radius centered on the rotation axis; a light guiding section that guides the laser beam reflected by the first reflecting surface to the second reflecting surface; Equipped with the first reflecting surface is configured such that an inclination angle with respect to the rotation axis varies along a circumference of the first radius, and the inclination angle of the first reflecting surface is configured such that, when the base is continuously rotated, the laser beam is recursively deflected in the first direction; the second reflecting surface is configured such that an inclination angle with respect to the rotation axis varies along the circumference of the second radius, and the inclination angle of the second reflecting surface is configured such that, when the base is continuously rotated, the laser beam is recursively deflected in the second direction. A laser irradiation device characterized by: [Matter 2] When the substrate is continuously rotated, the laser beam reflected from the second reflecting surface is recursively repeating deflection scanning of one frame along M scanning lines (M is an integer of 2 or more) that are different from each other in the second direction and extend along the first direction; 2. The laser irradiation device according to item 1, [Matter 3] The first reflecting surface is configured to include M sections (M is an integer of 2 or more) that are equal divisions of the circumference of the first radius, and the inclination angle of the first reflecting surface changes in the same manner in each section. 3. The laser irradiation device according to item 1 or 2. [Matter 4] The second reflecting surface is provided with M sections obtained by equally dividing a circumference of the second radius, and the inclination angle of the second reflecting surface is constant within each section, and the inclination angle of the second reflecting surface of each section is different. 4. The laser irradiation device according to item 3. [Matter 5] The second reflecting surface is configured such that the inclination angle increases monotonically along the circumference of the second radius. 4. The laser irradiation device according to any one of items 1 to 3, characterized in that: [Matter 6] The light guide section has at least three or more reflecting surfaces. 6. The laser irradiation device according to any one of items 1 to 5, [Matter 7] The light guide portion includes a prism having a total internal reflection surface formed thereon. 7. The laser irradiation device according to any one of items 1 to 6, [Matter 8] The light guide portion has a reflection surface having a free-form curved shape that is twisted relative to a flat surface. 8. The laser irradiation device according to any one of items 1 to 7, characterized in that: [Matter 9] the laser beam output from the laser light source is irradiated onto the first reflecting surface at a first irradiation position; the laser beam reflected by the first reflecting surface is guided to the light guiding section and irradiated onto the second reflecting surface at a second irradiation position; a line connecting the first irradiation position and the rotation axis and a line connecting the second irradiation position and the rotation axis are substantially perpendicular to each other; 9. The laser irradiation device according to any one of items 1 to 8, [Matter 10] The light guide unit includes a conjugate relay lens for making the first irradiation position and the second irradiation position conjugate with each other. 10. The laser irradiation device according to item 9. [Matter 11] 11. A laser irradiation system comprising the laser irradiation device according to any one of items 1 to 10, and a projection lens with a variable focal length. [Matter 12] The laser irradiation device according to any one of items 1 to 10, a light receiving sensor that detects light reflected by an object from the laser beam output from the laser irradiation device, An object detection device characterized by: [Matter 13] The laser irradiation device according to any one of items 1 to 10, a light receiving sensor that detects light reflected by an object from the laser beam output from the laser irradiation device, A distance measuring device characterized by: [Explanation of symbols]

[0095] 100...laser irradiation device / 101...laser light source / 103...front lens / 104...rear lens / 105...projection lens / 211, 211A...two-dimensional deflector / 212...motor / 213...reflecting surface / 214, 214a...reflecting surface / 300a, 300b...light guiding section / 301-304...reflecting mirror / 301A , 304A... Free-form surface mirror / 301B to 303B... Reflector / 500... Controller / 501... Light source control unit / 502... Motor drive unit / 503... Light receiving sensor unit / 504... Data processing unit / 505... I / O unit / IM1... Primary surface / IM2... Secondary surface / P1, P2... Irradiation position / R1, R2... Radius

Claims

1. a laser light source; a two-dimensional deflector that two-dimensionally deflects and scans the laser beam output from the laser light source in a first direction and a second direction, The two-dimensional deflector is a base body rotatable about a rotation axis; a first reflecting surface disposed on the base along a circumference of a first radius centered on the rotation axis; a second reflecting surface disposed on the base along a circumference of a second radius centered on the rotation axis; a light guiding section that guides the laser beam reflected by the first reflecting surface to the second reflecting surface; Equipped with the first reflecting surface is configured such that an inclination angle with respect to the rotation axis varies along a circumference of the first radius, and the inclination angle of the first reflecting surface is configured such that, when the base is continuously rotated, the laser beam is recursively deflected in the first direction; the second reflecting surface is configured such that an inclination angle with respect to the rotation axis varies along a circumference of the second radius, and the inclination angle of the second reflecting surface is configured such that, when the base is continuously rotated, the laser beam is recursively deflected in the second direction. A laser irradiation device characterized by:

2. When the substrate is continuously rotated, the laser beam reflected from the second reflecting surface is recursively repeating deflection scanning of one frame along M scanning lines (M is an integer of 2 or more) that are different from each other in the second direction and extend along the first direction; 2. The laser irradiation device according to claim 1.

3. the first reflecting surface is configured to include M sections (M is an integer of 2 or more) that are formed by equally dividing a circumference of the first radius, and the inclination angle of the first reflecting surface changes in the same manner in each section; 3. The laser irradiation device according to claim 2.

4. the second reflecting surface is provided with M sections obtained by equally dividing a circumference of the second radius, and the inclination angle of the second reflecting surface is constant within each section, and the inclination angle of the second reflecting surface of each section is different.

4. The laser irradiation device according to claim 3.

5. The second reflecting surface is configured such that the inclination angle increases monotonically along the circumference of the second radius.

2. The laser irradiation device according to claim 1.

6. The light guide portion has at least three or more reflecting surfaces.

6. The laser irradiation device according to claim 1, wherein the laser irradiation device is a laser beam irradiation device.

7. The light guide portion includes a prism having a total internal reflection surface formed thereon.

6. The laser irradiation device according to claim 1, wherein the laser irradiation device is a laser beam irradiation device.

8. The light guide portion has a reflection surface having a free-form curved shape that is twisted relative to a flat surface.

6. The laser irradiation device according to claim 1, wherein the laser irradiation device is a laser beam irradiation device.

9. the laser beam output from the laser light source is irradiated onto the first reflecting surface at a first irradiation position; the laser beam reflected by the first reflecting surface is guided to the light guiding section and irradiated onto the second reflecting surface at a second irradiation position; a line connecting the first irradiation position and the rotation axis and a line connecting the second irradiation position and the rotation axis are substantially perpendicular to each other; 6. The laser irradiation device according to claim 1, wherein the laser irradiation device is a laser beam irradiation device.

10. The light guide unit includes a conjugate relay lens for making the first irradiation position and the second irradiation position have a conjugate relationship.

10. The laser irradiation device according to claim 9.

11. 6. A laser irradiation system comprising: the laser irradiation device according to claim 1; and a projection lens having a variable focal length.

12. The laser irradiation device according to any one of claims 1 to 5, a light receiving sensor that detects light reflected by an object from the laser beam output from the laser irradiation device, An object detection device characterized by:

13. The laser irradiation device according to any one of claims 1 to 5, a light receiving sensor that detects light reflected by an object from the laser beam output from the laser irradiation device, A distance measuring device characterized by:

Images