Light projection device and distance measuring apparatus

Abstract

To provide a distance measuring apparatus capable of easily matching an irradiation region of a light projection device with an image plane region of a light receiving device.SOLUTION: A light projection device includes a light source that emits light, an optical scanner that scans the light, and a pre-scanning optical system that guides the light from the light source to the optical scanner. The optical scanner includes a rotatable reflector having a plurality of reflection surfaces on a peripheral surface. At least two of the plurality of reflection surfaces have different angles relative to a rotation axis of the reflector. The optical scanner scans the light in a main scanning direction by rotation of the reflector, and scans the light in a sub-scanning direction by the difference in the angle of the reflection surface. The light projection device has an adjustment shaft for adjusting a light projection angle in the sub-scanning direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a light projecting device and a distance measuring device. [Background technology]

[0002] Conventionally, a distance measuring device has been disclosed in which a scanning type light projecting device and a light receiving device are configured non-coaxially.

[0003] Also disclosed is a technique for providing a plurality of reflecting surfaces at different angles relative to the rotation axis of a polygon mirror. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-159067 Summary of the Invention [Problem to be solved by the invention]

[0005] In this type of distance measuring device, it is necessary to align the illumination area of ​​the light projecting device with the image plane area of ​​the light receiving device.

[0006] The problem to be solved by the present invention is to provide a distance measuring device that can easily align the illumination area of ​​the light projecting device with the image plane area of ​​the light receiving device. [Means for solving the problem]

[0007] A light projection device according to an embodiment includes a light source that emits light, an optical scanner that scans the light, and a pre-scanning optical system that guides the light from the light source to the optical scanner. The optical scanner includes a rotatable reflector having multiple reflective surfaces on its circumferential surface. At least two of the multiple reflective surfaces have different angles relative to the rotation axis of the reflector. The optical scanner scans the light in the main scanning direction by rotating the reflector, and scans the light in the sub-scanning direction by changing the angles of the reflective surfaces. The light projection device includes an adjustment axis for adjusting the projection angle in the sub-scanning direction. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a distance measuring device according to an embodiment, illustrating a state before adjustment of an illumination area of ​​a light projecting device and an image plane area of ​​a light receiving device. [Figure 2] FIG. 2 is a schematic diagram showing the distance measuring device according to the embodiment, illustrating the state after adjustment of the irradiation area of ​​the light projecting device and the image plane area of ​​the light receiving device. [Figure 3] FIG. 3 is a diagram showing an optical system of the light projecting device. [Figure 4] FIG. 4 is a perspective view of the light projecting device. [Figure 5] FIG. 5 is another perspective view of the floodlight device as seen from a different direction than FIG. [Figure 6] FIG. 6 is an exploded perspective view of the light projecting device shown in FIGS. [Figure 7] FIG. 7 is a perspective view of a polygon mirror of an optical scanner of a light projection device. [Figure 8] FIG. 8 is a plan view of the polygon mirror shown in FIG. [Figure 9] FIG. 9 is a diagram schematically showing three reflecting surfaces of the polygon mirror shown in FIG. [Figure 10] FIG. 10 is a diagram showing three irradiation areas by three reflecting surfaces of the light projecting device and an image plane area of ​​the light receiving device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the drawings used in the following description of the embodiments, some configurations may be omitted in order to make the description easier to understand.

[0010] A distance measuring device 1 according to an embodiment will be described with reference to Figures 1 and 2. Figures 1 and 2 are schematic diagrams showing the distance measuring device 1 according to an embodiment.

[0011] For convenience, an XYZ coordinate system is set as shown in Figures 1 and 2. The X axis is perpendicular to the paper surface of Figures 1 and 2. The Y axis is perpendicular to the X axis and extends up and down. The Z axis is perpendicular to the X axis and extends left and right. Hereinafter, the Z direction may be referred to as the forward direction, and the Y direction as the upward direction.

[0012] The distance measuring device 1 is a device for acquiring information on the distance to a target. The distance measuring device 1 includes a light projecting device 2 and a light receiving device 3.

[0013] The light projecting device 2 scans in the X direction while projecting light that spreads along the Y axis in the Z direction. The light projecting device 2 also scans in the Y direction. Hereinafter, the X direction will also be referred to as the main scanning direction, and the Y direction will also be referred to as the sub-scanning direction. For example, the light projecting device 2 creates one of three irradiation areas TAa, TAb, and TAc that partially overlap in the sub-scanning direction by one scan in the main scanning direction. The light projecting device 2 forms the irradiation area TA as a whole by three scans in the main scanning direction.

[0014] The light receiving device 3 receives light from the image plane area IA. The light receiving device 3 has an imaging lens 4 and a two-dimensional sensor 5. The imaging lens 4 forms an image of the image plane area IA on the two-dimensional sensor 5. The two-dimensional sensor 5 acquires and outputs information about the image formed by the imaging lens 4.

[0015] The distance measuring device 1 also has a control circuit 8. The control circuit 8 controls the light projecting device 2 and the light receiving device 3. The control circuit 8 also calculates the distance to a target in front of the distance measuring device 1 based on the scanning information of the light projecting device 2 and the light receiving information of the light receiving device 3.

[0016] The light-projecting device 2 and the light-receiving device 3 are housed in and fixed to a cover housing 6. The cover housing 6 has a cover glass 7 in front of the light-projecting device 2 and the light-receiving device 3. The cover glass 7 transmits light projected forward from the light-projecting device 2 and transmits light traveling from the image surface area IA toward the light-receiving device 3.

[0017] In the distance measuring device 1, it is necessary to align the irradiation area TA of the light projecting device 2 with the image plane area IA of the light receiving device 3.

[0018] Fig. 1 shows the state before adjustment of the illumination area TA of the light projecting device 2 and the image plane area IA of the light receiving device 3. In detail, Fig. 1 shows, as an example of the state before adjustment, a state in which the optical axis of the light projecting device 2 and the optical axis of the light receiving device 3 are parallel. In this case, the illumination area TA of the light projecting device 2 does not cover the image area IA of the light receiving device 3, and therefore there are areas where the distance cannot be measured.

[0019] To avoid such a situation, the light projecting device 2 is designed to be able to adjust the light projection angle in the sub-scanning direction. That is, the light projecting device 2 has a rotation adjustment shaft 201 for adjusting the light projection angle in the sub-scanning direction. Although only one rotation adjustment shaft 201 is depicted in FIGS. 1 and 2, the light projecting device 2 actually has a pair of rotation adjustment shafts 201. The pair of rotation adjustment shafts 201 extend coaxially parallel to the X-axis. The pair of rotation adjustment shafts 201 are fitted into a pair of shaft holes (not shown) provided in the cover housing 6. This allows the angle of the light projecting device 2 to be adjusted in the sub-scanning direction around the rotation adjustment shaft 201.

[0020] The floodlight device 2 has fixing screw holes 202. For example, the floodlight device 2 has three pairs of fixing screw holes 202. Each pair of fixing screw holes 202 extends coaxially parallel to the X-axis. After adjusting the angle, the floodlight device 2 is fixed to the cover housing 6 by fastening screws into the fixing screw holes 202 through holes (not shown) formed in the cover housing 6.

[0021] 2 shows the state after adjustment of the illumination area TA of the light projector 2 and the image area IA of the light receiving device 3. In the state after adjustment, by adjusting the angle of the light projector 2 in the sub-scanning direction, the illumination area TA of the light projector 2 covers the image area IA of the light receiving device 3. As a result of this adjustment, it is possible to measure the distance to the target in any of the image areas of the light receiving device 3.

[0022] Next, the optical system of the light projection device 2 will be described with reference to Fig. 3. Fig. 3 is a diagram showing the optical system of the light projection device 2.

[0023] The light projecting device 2 includes a light source 203 that emits light, an optical scanner 210 that scans the light, and a pre-scanning optical system that guides the light from the light source 203 to the optical scanner 210 .

[0024] The pre-scanning optical system has a collimator lens 204, a folding mirror 205, and a cylindrical lens 206. The collimator lens 204 collimates the light emitted from the light source 203. The folding mirror 205 changes the traveling direction of the light that has passed through the collimator lens 204. The cylindrical lens 206 converges the incident light in one direction and shapes it into an elongated shape.

[0025] The optical scanner 210 includes a polygon mirror 207 and a drive motor 209. The polygon mirror 207 is a rotatable reflector having a plurality of reflecting surfaces on its circumferential surface. The drive motor 209 rotates the polygon mirror 207.

[0026] At least two of the multiple reflective surfaces of the polygon mirror 207 have different angles with respect to the rotation axis of the polygon mirror 207. For example, all of the multiple reflective surfaces have different angles with respect to the rotation axis of the polygon mirror 207.

[0027] The pre-scanning optical system (collimator lens 204, folding mirror 205, cylindrical lens 206) guides the light emitted from the light source 203 to the polygon mirror 207 of the optical scanner 210. That is, the optical axis OAa of the pre-scanning optical system is folded back by the folding mirror 205 toward the polygon mirror 207.

[0028] The optical scanner 210 scans the light in the main scanning direction by rotating the polygon mirror 207, and scans the light in the sub-scanning direction by changing the angle of the reflecting surface.

[0029] Next, details of the floodlight device 2 will be described with reference to Fig. 4 to Fig. 6. Fig. 4 is a perspective view of the floodlight device 2. Fig. 5 is another perspective view of the floodlight device 2 seen from a different direction than Fig. 4. Fig. 6 is an exploded perspective view of the floodlight device 2.

[0030] The light projecting device 2 has an optical scanner 210 and a light projecting device base 211 that holds the optical scanner 210. The optical scanner 210 is fixed to the light projecting device base 211 by screws 221.

[0031] The optical scanner 210 has a bracket 216. The bracket 216 is a cubic box-shaped body that houses the polygon mirror 207 and holds the drive motor 209.

[0032] The bracket 216 has a pair of rotation adjustment shafts 201. As described above, the pair of rotation adjustment shafts 201 extend coaxially. As shown in Fig. 6 , one of the pair of rotation adjustment shafts 201 protrudes from the side of the bracket 216 facing the floodlight device base 211, and the other of the pair of rotation adjustment shafts 201 protrudes from the opposite side of the bracket 216.

[0033] Hereinafter, for convenience, the side facing the floodlight base 211 may be referred to as the first side, and the opposite side may be referred to as the second side. The terms first side and second side may also be used to refer to the floodlight 2 after assembly.

[0034] The bracket 216 also has a locating protrusion 219. The locating protrusion 219 protrudes from a first side of the bracket 216.

[0035] The projector base 211 has a reference surface 212 facing the bracket 216. The reference surface 212 is a flat surface for ensuring the necessary assembly accuracy. The projector base 211 also has a reference hole 213, a reference elongated hole 214, and a plurality of through holes 215. The reference hole 213 is a through hole for receiving the rotation adjustment shaft 201. The reference elongated hole 214 is a through hole for receiving a positioning protrusion 219. The through hole 215 is a through hole for passing a screw 221 for fixing the optical scanner 210 to the projector base 211.

[0036] The bracket 216 also has a plurality of reference surfaces 217. The reference surfaces 217 are flat surfaces that abut against the reference surfaces 212 of the floodlight device base 211 to ensure the necessary assembly precision. The bracket 216 also has a plurality of screw holes 220. The plurality of screw holes 220 are formed in the plurality of reference surfaces 217, respectively.

[0037] The plurality of screw holes 220 in the bracket 216 and the plurality of through holes 215 in the floodlight base 211 are formed so as to align with each other when the bracket 216 and the floodlight base 211 are placed face to face.

[0038] A reference surface 217 of the bracket 216 abuts against a reference surface 212 of the floodlight device base 211. A rotation adjustment shaft 201 of the bracket 216 precisely fits into a reference hole 213 of the floodlight device base 211. Furthermore, a positioning protrusion 219 of the bracket 216 precisely fits into a reference elongated hole 214 of the floodlight device base 211. This allows the relative positions of the bracket 216 and the floodlight device base 211 to be determined with high precision.

[0039] In this state, the plurality of screws 221 are passed through the plurality of through holes 215 of the light projector base 211 and tightened into the plurality of fixing screw holes 202 of the bracket 216. This fixes the optical scanner 210 to the light projector base 211.

[0040] As described above, the pair of rotation adjustment shafts 201 are fitted into a pair of shaft holes (not shown) provided in the cover housing 6. Therefore, the rotation adjustment shaft 201 on the first side of the bracket 216 penetrates the reference hole 213 of the floodlight base 211 and protrudes to the first side.

[0041] The pair of rotation adjustment shafts 201 are both formed on the bracket 216 of the optical scanner 210. For example, the pair of rotation adjustment shafts 201 are formed integrally with the bracket 216. This makes it possible to control the accuracy of the floodlight device 2 by controlling the accuracy of the bracket 216.

[0042] In other words, if the first-side rotation adjustment shaft 201 is provided on the floodlight base 211 instead of the bracket 216, the component tolerances of the bracket 216 and the floodlight base 211 will affect the accuracy of the first-side rotation adjustment shaft 201 and the second-side rotation adjustment shaft 201.

[0043] In contrast to this, in the floodlight device 2 according to the embodiment, the pair of rotation adjustment shafts 201 are formed on the common bracket 216, and therefore can be easily formed with high coaxiality.

[0044] 4, bracket 216 of optical scanner 210 has two protrusions 222 protruding toward the second side. Furthermore, floodlight device base 211 has a columnar portion 223 extending toward the second side. Protrusions 222 of bracket 216 and the end surface on the second side of columnar portion 223 of floodlight device base 211 are located on the same plane.

[0045] As described above, for example, the floodlight device 2 has three pairs of fixing screw holes 202. The three pairs of fixing screw holes 202 include three fixing screw holes 202 on a first side and three fixing screw holes 202 on a second side.

[0046] All three fixing screw holes 202 on the first side are formed in floodlight device base 211, as shown in Fig. 5. Two fixing screw holes 202 on the second side are formed in two protruding portions 222 of bracket 216, respectively, as shown in Fig. 4. The remaining fixing screw hole 202 on the second side is formed in columnar portion 223 of floodlight device base 211.

[0047] Next, polygon mirror 207 of optical scanner 210 of light projecting device 2 will be described with reference to Fig. 7 to Fig. 9. Fig. 7 is a perspective view of polygon mirror 207. Fig. 8 is a plan view of polygon mirror 207. Fig. 9 is a diagram schematically showing reflecting surfaces 2071, 2072, and 2073 of polygon mirror 207.

[0048] The polygon mirror 207 has three reflecting surfaces 2071, 2072, and 2073. This provides a wide irradiation area in the main scanning direction. The reflecting surfaces 2071, 2072, and 2073 surround the periphery of the polygon mirror 207. This allows the light to scan in the main scanning direction without any time intervals.

[0049] For example, the reflecting surfaces 2071, 2072, and 2073 are flat reflecting surfaces. The reflecting surfaces 2071, 2072, and 2073 have the same width in the main scanning direction. The reflecting surfaces 2071, 2072, and 2073 also have the same height in the sub-scanning direction. The reflecting surfaces 2071, 2072, and 2073 are oriented at different angles relative to the rotation axis 2070 of the polygon mirror 207.

[0050] 8, the reflecting surfaces 2071, 2072, and 2073 share a common inscribed circle 2074 on the same plane perpendicular to the rotation axis 2070 of the polygon mirror 207. The reflecting surfaces 2071, 2072, and 2073 form angles around tangents 2075, 2076, and 2077, respectively, of the inscribed circle 2074. The tangents 2075, 2076, and 2077 of the inscribed circle 2074 are located at the center of the height of the reflecting surfaces 2071, 2072, and 2073 in the sub-scanning direction.

[0051] Consider a state in which tangents 2075, 2076, and 2077 of the reflecting surfaces 2071, 2072, and 2073 are perpendicular to the optical axis of the pre-scan optical system (collimator lens 204, reflecting mirror 205, and cylindrical lens 206) described with reference to Fig. 3. For convenience, this state is referred to as a state in which the swing angle of the polygon mirror 207 is zero for each of the reflecting surfaces 2071, 2072, and 2073.

[0052] 9 shows the overlapping reflecting surfaces 2071, 2072, and 2073 when the swing angle of the polygon mirror 207 is zero. Fig. 9 also shows the chief ray Ls of incident light guided to the polygon mirror 207 by the pre-scan optical system, and the chief rays La, Lb, and Lc of reflected light reflected by the reflecting surfaces 2071, 2072, and 2073, respectively.

[0053] 9, the pre-scanning optical system guides the chief ray Ls of the light incident on the polygon mirror 207 to the position of the inscribed circle 2074. In other words, the pre-scanning optical system guides the chief ray Ls of the light incident on the polygon mirror 207 to tangents 2075, 2076, and 2077 of the inscribed circle 2074 on the reflecting surfaces 2071, 2072, and 2073, respectively.

[0054] The chief ray Ls of light incident on each of the reflecting surfaces 2071, 2072, and 2073 is reflected by each of the reflecting surfaces 2071, 2072, and 2073, with the position of the inscribed circle 2074 as the origin 208. That is, the chief rays La, Lb, and Lc of the light reflected by each of the reflecting surfaces 2071, 2072, and 2073 intersect at the origin 208.

[0055] For example, for reflecting surface 2072, which is midway between the angles of three reflecting surfaces 2071, 2072, and 2073 around tangents 2075, 2076, and 2077 of inscribed circle 2074, the other two reflecting surfaces 2071 and 2073 are inclined by the same angle but in opposite directions around tangents 2075 and 2077 of inscribed circle 2074.

[0056] The reflecting surfaces 2071, 2072, and 2073 have different angles with respect to the rotation axis 2070 of the polygon mirror 207. Therefore, as the polygon mirror 207 rotates, the reflecting surfaces 2071, 2072, and 2073 that reflect the light incident on the polygon mirror 207 change, causing the polygon mirror 207 to scan the reflected light in the sub-scanning direction in three stages.

[0057] 1 and 2, the light projecting device 2 sequentially creates an illumination area TAa by the reflecting surface 2071, an illumination area TAb by the reflecting surface 2072, and an illumination area TAc by the reflecting surface 2073. The illumination area TAa, the illumination area TAb, and the illumination area TAc partially overlap in the sub-scanning direction and collectively form the illumination area TA of the light projecting device 2.

[0058] FIG. 10 shows three irradiation areas TAa, TAb, and TAc by three reflecting surfaces 2071, 2072, and 2073 of the light projecting device 2 on an image plane 100 m away, and an image plane area IA of the light receiving device 3.

[0059] The three irradiation areas TAa, TAb, and TAc partially overlap in the sub-scanning direction and collectively cover the image area IA of the light receiving device 3. Therefore, the distance measuring device 1 can measure the distance to the target in any of the image areas IA of the light receiving device 3.

[0060] As described with reference to FIGS. 1 and 2, the angle of the projector 2 can be adjusted in the sub-scanning direction around the rotation adjustment shaft 201. When adjusting the angle of the projector 2 in the sub-scanning direction, it is preferable that the irradiation position moves linearly. For this reason, in the distance measuring device 1, the central axis of the rotation adjustment shaft 201 of the projector 2 coincides with the starting point 208 shown in FIG. 9. In other words, the central axis of the rotation adjustment shaft 201 of the projector 2 coincides with the tangents 2075, 2076, and 2077 of the inscribed circle 2074 on each of the reflecting surfaces 2071, 2072, and 2073 when the swing angle of the polygon mirror 207 is zero.

[0061] If the position of the rotation adjustment axis 201 is far away from the starting point 208, there is a possibility that, when the angle of the light projecting device 2 in the sub-scanning direction is adjusted, the focal position of the light reflected by each of the reflecting surfaces 2071, 2072, and 2073 may shift.

[0062] In contrast to this, in the distance measuring device 1, the central axis of the rotation adjustment shaft 201 of the light projecting device 2 coincides with the origin 208 of the light reflected by each of the reflecting surfaces 2071, 2072, and 2073 when the swing angle of the polygon mirror 207 is zero. Therefore, when the angle of the light projecting device 2 in the sub-scanning direction is adjusted, the shift in the focal position of the light reflected by each of the reflecting surfaces 2071, 2072, and 2073 is minimized.

[0063] As a result, in the distance measuring device 1 according to the embodiment, it is possible to easily align with high precision the irradiation area TA of the light projecting device 2 and the image plane area IA of the light receiving device 3. In other words, the distance measuring device 1 makes it easy to align the irradiation area TA of the light projecting device 2 and the image plane area IA of the light receiving device 3.

[0064] In the embodiment, an example has been shown in which polygon mirror 207 has three reflecting surfaces 2071, 2072, and 2073, but polygon mirror 207 may have four or more reflecting surfaces. In this case, the four or more reflecting surfaces are inclined at equal intervals around the tangent to inscribed circle 2074, with respect to a virtual plane of the average angle of the four or more reflecting surfaces around the tangent to inscribed circle 2074.

[0065] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0066] The invention disclosed in the embodiments will be described below.

[0067] [1] A light projecting device that projects and scans light and is used in a distance measuring device that acquires distance information to a target, the light projecting device includes a light source that emits light, an optical scanner that scans the light, and a pre-scanning optical system that guides the light from the light source to the optical scanner; the optical scanner has a rotatable reflector having a plurality of reflecting surfaces on its circumferential surface, at least two of the plurality of reflecting surfaces having different angles with respect to a rotation axis of the reflector, the light is scanned in a main scanning direction by the rotation of the reflector, and the light is scanned in a sub-scanning direction by the difference in the angles of the reflecting surfaces; the light projecting device has an adjustment shaft for adjusting the light projection angle in the sub-scanning direction; Floodlight.

[0068] [2] the plurality of reflecting surfaces have a common inscribed circle on the same plane perpendicular to the rotation axis of the reflector, the plurality of reflecting surfaces are angled about a tangent to the inscribed circle; the pre-scanning optical system guides the light to the reflector and guides a chief ray of the light to a position of the inscribed circle; a central axis of the adjustment axis coincides with a tangent to the inscribed circle that is perpendicular to the optical axis of the pre-scanning optical system; [1] The floodlight device according to [1].

[0069] [3] The plurality of reflective surfaces are three or more reflective surfaces surrounding the periphery of the reflector. [2] The floodlight device according to [2].

[0070] [4] the plurality of reflective surfaces all have different angles relative to the axis of rotation of the reflector; [3] The floodlight device according to [3].

[0071] [5] all of the plurality of reflecting surfaces have the same width in the main scanning direction; [3] The floodlight device according to [3].

[0072] [6] the plurality of reflecting surfaces have the same height in the sub-scanning direction, and the tangent to the inscribed circle is located at the center of the height of the reflecting surfaces; [2] The floodlight device according to [2].

[0073] [7] the plurality of reflecting surfaces are inclined at an evenly distributed angle around the tangent line of the inscribed circle, with respect to a virtual plane of an average of angles of the plurality of reflecting surfaces around the tangent line of the inscribed circle; [2] The floodlight device according to [2].

[0074] [8] the plurality of reflecting surfaces are three flat reflecting surfaces, With respect to a reflecting plane intermediate the angles of the three reflecting planes about the tangent to the inscribed circle, the other two reflecting planes are inclined by the same angle in opposite directions about the tangent to the inscribed circle. [2] The floodlight device according to [2].

[0075] [9] a plurality of irradiation areas formed by the plurality of reflecting surfaces partially overlap with each other in the sub-scanning direction; [2] The floodlight device according to [2].

[0076]

[10] [1] The floodlight device according to the present invention; a light receiving device that receives light from a predetermined area; Ranging device. [Explanation of symbols]

[0077] 1... distance measuring device, 2... light projecting device, 3... light receiving device, 4... imaging lens, 5... two-dimensional sensor, 6... cover housing, 7... cover glass, 8... control circuit, 201... rotation adjustment shaft, 202... fixing screw hole, 203... light source, 204... collimator lens, 205... folding mirror, 206... cylindrical lens, 207... polygon mirror, 208... starting point, 209... drive motor, 210... optical scanner, 211 ...Projector base, 212...reference surface, 213...reference hole, 214...reference oblong hole, 215...through hole, 216...bracket, 217...reference surface, 219...positioning protrusion, 220...screw hole, 221...screw, 222...protrusion, 223...columnar portion, 2070...rotation axis, 2071...reflective surface, 2072...reflective surface, 2073...reflective surface, 2074...inscribed circle, 2075...tangent, 2076...tangent, 2077...tangent.

Claims

1. A light projecting device that projects and scans light and is used in a distance measuring device that acquires distance information to a target, a light source that emits the light; an optical scanner that scans the light; a pre-scanning optical system that guides the light from the light source to the optical scanner; the optical scanner has a rotatable reflector having a plurality of reflecting surfaces on its circumferential surface, at least two of the plurality of reflecting surfaces being at different angles with respect to a rotation axis of the reflector, the light is scanned in a main scanning direction by the rotation of the reflector, and the light is scanned in a sub-scanning direction by the difference in the angles of the reflecting surfaces; the light projecting device has an adjustment axis for adjusting the projection direction of the light in the sub-scanning direction; Floodlight.

2. the plurality of reflecting surfaces have a common inscribed circle on the same plane perpendicular to the rotation axis of the reflector, the plurality of reflecting surfaces are angled about a tangent to the inscribed circle; the pre-scanning optical system guides the light to the reflector and guides a chief ray of the light to a position of the inscribed circle; a central axis of the adjustment axis coincides with a tangent to the inscribed circle that is perpendicular to the optical axis of the pre-scanning optical system; The floodlight device according to claim 1 .

3. The plurality of reflective surfaces are three or more reflective surfaces surrounding the periphery of the reflector. The floodlight device according to claim 2 .

4. the plurality of reflecting surfaces have the same height in the sub-scanning direction, and the tangent to the inscribed circle is located at the center of the height of the reflecting surfaces; The floodlight device according to claim 2 .

5. the plurality of reflecting surfaces are three flat reflecting surfaces, With respect to a reflecting plane intermediate the angles of the three reflecting planes about the tangent to the inscribed circle, the other two reflecting planes are inclined by the same angle in opposite directions about the tangent to the inscribed circle. The floodlight device according to claim 2 .

6. The light projecting device according to claim 1; a light receiving device that receives light from a predetermined area; Ranging device.

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