Distance measuring device

Abstract

To provide a distance measuring device with which it is possible to suppress erroneous measurement due to reflected light from a case.SOLUTION: An optical module accommodated in a case comprises: a laser light source; a first light receiving element; a scanning mirror for reflecting emitted light from the laser light source toward a first portion composed of a curved surface of the case and receiving incidence of first reflected light of the light having been emitted from the first portion to the outside of the case and reflected by a measurement object; and a transmission / reflection member arranged between the laser light source and the scanning mirror, for passing emitted light from the laser light source through toward the scanning mirror and reflecting the first reflected light from the measurement object that returns via the scanning mirror toward the first light receiving element. A first optical axis of light entering the first portion from the scanning mirror and a second optical axis of second reflected light entering the first portion of the case from the scanning mirror and being reflected by the first portion are nonparallel.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a distance measurement device. [Background technology]

[0002] In distance measurement using laser light, the reflected light from the object is detected and the distance to the object is calculated. For example, in underwater distance measurement, it is necessary to put the optical module containing the laser light source and the light receiving element into a case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-155619 A [Patent Document 2] JP 2019-105550 A [Patent Document 3] JP 2015-49192 A Summary of the Invention [Problem to be solved by the invention]

[0004] If an optical module is housed inside a case, there is a concern that reflected light from the case will be input to the light receiving element, resulting in an erroneous measurement of the distance to the object to be measured.

[0005] An object of the present invention is to provide a distance measurement device that can suppress erroneous measurements caused by light reflected from a case. [Means for solving the problem]

[0006] A distance measurement device according to an embodiment of the present invention includes a case having a first portion formed of a curved surface, and an optical module housed in the case. The optical module includes a laser light source, a first light receiving element, a scanning mirror that reflects light emitted from the laser light source toward the first portion of the case and receives first reflected light emitted from the first portion to the outside of the case and reflected by a measurement object, and a transmissive reflecting member that is disposed between the laser light source and the scanning mirror and transmits the light emitted from the laser light source toward the scanning mirror and reflects the first reflected light from the measurement object returning via the scanning mirror toward the first light receiving element. A first optical axis of light incident on the first portion from the scanning mirror and a second optical axis of a second reflected light incident on the first portion of the case from the scanning mirror and reflected by the first portion are non-parallel. Effect of the Invention

[0007] According to the distance measurement device of the present invention, it is possible to suppress erroneous measurements caused by reflected light from the case. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a distance measuring device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Diagram 3] 10 is a schematic diagram showing the positional relationship between a case and a scanning mirror in a distance measurement device according to a second embodiment of the present invention. FIG. [Figure 4] FIG. 11 is a schematic diagram of a distance measuring device according to a third embodiment of the present invention. [Diagram 5] 5 is a schematic cross-sectional view taken along line VV in FIG. 4. [Figure 6] FIG. 11 is a schematic diagram of a distance measuring device according to a fourth embodiment of the present invention. [Figure 7] 13 is a schematic diagram showing the positional relationship between a case and a scanning mirror in a distance measurement device according to a fifth embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals.

[0010] [First embodiment] FIG. 1 is a schematic diagram of a distance measurement device 1 according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG.

[0011] The distance measurement device 1 includes a case 100 and an optical module 10 housed in the case 100. The distance measurement device 1 can be used, for example, underwater. The case 100 protects the optical module 10 from water. The case 100 is also resistant to water pressure.

[0012] The case 100 has a first portion 105. The first portion 105 is a portion that transmits light from the optical module 10 to the outside of the case 100 and allows light reflected by a measurement target 200 located outside the case 100 to enter the case 100. In the case 100, at least the first portion 105 is transparent to the light from the optical module 10 and the light reflected from the measurement target 200, and is made of, for example, resin or glass. Examples of resin include acrylic and polycarbonate.

[0013] 1 shows a cross section of the case 100 parallel to its central axis C1. The central axis C1 connects the center of the first end face 101 and the center of the second end face 102. One or both of the first end face 101 and the second end face 102 may be spherical or conical. FIG. 2 shows a cross section of the case 100 perpendicular to the central axis C1.

[0014] The case 100 has a cylindrical shape having a first end face 101, a second end face 102, and a side face 103. By making the case 100 cylindrical, high pressure resistance against water pressure can be obtained. The first end face 101 and the second end face 102 are, for example, circular flat surfaces. The side face 103 is a curved surface as shown in FIG. 2. The side face 103 includes a first portion 105. That is, the first portion 105 is a curved surface.

[0015] The optical module 10 includes a laser light source 11, a first light receiving element 16, a second light receiving element 17, a beam splitter 12, a transmissive reflector 13, a scanning mirror 14, a motor 15 that rotates the scanning mirror 14, and a condenser lens 18.

[0016] The laser light source 11 is, for example, a semiconductor laser (or a laser diode) using a semiconductor as a medium that causes stimulated emission. Alternatively, a solid-state laser using an insulating solid material as a medium can be used as the laser light source 11. When the distance measurement device 1 is used underwater, the oscillation wavelength of the laser light source 11 is preferably 380 nm or more and 550 nm or less, which has a low attenuation rate in water. The transmittance of the first part 105 of the case 100 for light with a wavelength of 380 nm or more and 550 nm or less is 90% or more. The laser light source 11 outputs, for example, a pulse train of laser light. Alternatively, the laser light source 11 may output a single pulse of laser light. The optical axis of the emitted light L1 from the laser light source 11 is inclined with respect to the central axis C1 of the cylindrical case 100.

[0017] The beam splitter 12 is disposed between the laser light source 11 and the transmissive reflector 13. The beam splitter 12 splits the output light L1 from the laser light source 11 into a transmitted light directed toward the transmissive reflector 13 and a third reflected light R3 directed toward the second light receiving element 17.

[0018] The transmissive reflecting member 13 is disposed between the beam splitter 12 and the scanning mirror 14. The transmissive reflecting member 13 has a hole portion 13a that transmits the emitted light L1 from the laser light source 11 that has been transmitted through the beam splitter 12 toward the scanning mirror 14. The transmissive reflecting member 13 also has a mirror portion 13b that reflects a first reflected light R1 from the measurement target 200 that returns via the scanning mirror 14 toward the first light receiving element 16. The first reflected light R1 is indicated by a dashed line in Fig. 1. The first reflected light R1 is also indicated by a dashed line in Figs. 4 and 6, which will be described later.

[0019] The scanning mirror 14 has a reflecting surface 14a inclined with respect to the optical axis of the emitted light L1 from the laser light source 11. The scanning mirror 14 reflects the emitted light L1 from the laser light source 11 toward the first portion 105 of the case 100. Furthermore, the scanning mirror 14 receives a first reflected light R1 which is emitted light L3 transmitted through the first portion 105 and reflected by the measurement target 200, transmitted through the first portion 105 again, and returned to the inside of the case 100. As shown in FIG. 2, the central axis C1 of the case 100 passes through the reflecting surface 14a of the scanning mirror 14.

[0020] The scanning mirror 14 has a rotation shaft 14b connected to a motor 15. The scanning mirror 14 can rotate around the rotation shaft 14b by being driven by the motor 15. The rotation shaft 14b of the scanning mirror 14 is inclined with respect to the central axis C1 of the case 100.

[0021] The first light receiving element 16 receives the first reflected light R1 that is reflected by the measurement target 200 and passes through the scanning mirror 14 and the mirror portion 13b, and converts it into an electrical signal. The first light receiving element 16 is, for example, a photodiode. A condenser lens 18 is disposed between the first light receiving element 16 and the transmissive reflector 13.

[0022] The second light receiving element 17 receives the third reflected light R3, which is part of the emitted light L1 from the laser light source 11 and is reflected and split by the beam splitter 12, and converts it into an electrical signal. The second light receiving element 17 is, for example, a photodiode.

[0023] The optical axis of light L2 incident on first portion 105 of case 100 from scanning mirror 14 is defined as a first optical axis A1. The first optical axis A1 coincides with the straight line representing light L2 in Fig. 1. The optical axis of second reflected light R2 incident on first portion 105 from scanning mirror 14 and reflected by first portion 105 is defined as a second optical axis A2. The second optical axis A2 coincides with the straight line representing second reflected light R2 in Fig. 1.

[0024] FIG. 1 shows a cross-sectional view of case 100 parallel to the emitted light L1 from laser light source 11. In this cross-sectional view, a first portion 105 of case 100 into which light L2 from scanning mirror 14 is incident is inclined with respect to first optical axis A1. In the cross-sectional view of FIG. 1, light L2 from scanning mirror 14 is not perpendicularly incident on first portion 105. With this structure, the first optical axis A1 and second optical axis A2 are non-parallel. That is, the second optical axis A2 is inclined with respect to the first optical axis A1.

[0025] Next, a method for measuring the distance to the measurement target 200 using the distance measurement device 1 of this embodiment will be described. The distance measurement device 1 is installed, for example, underwater or mounted on a device that moves underwater, and can measure the distance to the measurement target 200 located outside the case 100.

[0026] A part of the emitted light L1 from the laser light source 11 passes through the beam splitter 12. Another part of the emitted light L1 from the laser light source 11 is reflected by the beam splitter 12 and enters the second light receiving element 17. The second light receiving element 17 receives a third reflected light R3 that does not pass through the object 200 to be measured.

[0027] The emitted light L1 of the laser light source 11 that has passed through the beam splitter 12 passes through the hole 13a of the transmissive reflector 13 and enters the reflecting surface 14a of the scanning mirror 14. The light that has entered the reflecting surface 14a is reflected by the reflecting surface 14a. The light L2 reflected by the reflecting surface 14a enters the first portion 105 on the side surface 103 of the case 100. By the rotation of the scanning mirror 14, the light L2 reflected by the reflecting surface 14a is scanned once or repeatedly within a range of a predetermined angle centered on the rotation axis 14b. The scanning range centered on the rotation axis 14b may be 360 ​​degrees or less than 360 degrees. The first portion 105 is continuous along the scanning range of the light L2. The scanning mirror may be two or more mirrors that can rotate around different axes to scan the irradiated light.

[0028] The light L2 incident on the first portion 105 is transmitted from the first portion 105 to the outside of the case 100. When the light L3 from the optical module 10 that has transmitted to the outside of the case 100 is irradiated onto the measurement object 200, it is reflected by the measurement object 200. The light L3 is, for example, diffusely reflected by the measurement object 200.

[0029] The first reflected light R1 reflected by the measurement object 200 passes through the first portion 105 and enters the case 100, and is reflected by the reflecting surface 14a of the scanning mirror 14 toward the transmission reflection member 13. The first reflected light R1 from the measurement object 200 reflected by the mirror portion 13b of the transmission reflection member 13 is collected by the collecting lens 18 and enters the first light receiving element 16.

[0030] On the other hand, the second light receiving element 17 receives the third reflected light R3 that does not pass through the measurement object 200. This third reflected light R3 becomes a reference light for calculating the distance to the measurement object 200 by using the first reflected light R1 from the measurement object 200. The distance to the measurement object 200 is calculated from the time difference between the time (reference time) when the second light receiving element 17 receives the third reflected light R3 (reference light) and the time when the first light receiving element 16 receives the first reflected light R1.

[0031] In addition, without disposing the beam splitter 12 and the second light receiving element 17, the distance to the object 200 to be measured may be calculated from the time difference between the emission timing (emission time) of the laser light pulse from the laser light source 11 and the time when the first light receiving element 16 receives the first reflected light R1.

[0032] In order to obtain an accurate time difference between the reference time and the time when the first light receiving element 16 receives the first reflected light R1, it is preferable to use the time when the light is received by the second light receiving element 17 as the reference time rather than using the emission time of the laser light source 11 itself.

[0033] The effects of the distance measurement device 1 of this embodiment will be described. It is not realistic to achieve 100% transmittance for light L2 incident on first portion 105 from scanning mirror 14, and a second reflected light R2 is generated that is reflected by first portion 105 into case 100. The reflection of light L2 in first portion 105 includes reflection at a first interface between a medium inside case 100 (e.g., air) and first portion 105, and reflection at a second interface between first portion 105 and a medium outside case 100 (e.g., water).

[0034] In this embodiment, the scanning mirror 14 is configured to receive the first reflected light R1 from the measurement object 200 while scanning the irradiated light outside the case 100 by rotating the scanning mirror 14. That is, the first reflected light R1 from the measurement object 200 returns to the scanning mirror 14 along the same path (coaxial path) as the light L2 from the scanning mirror 14 to the first portion 105.

[0035] 1, when the optical axis A1 of the light L2 is perpendicular to the first portion 105, the second reflected light R2 reflected by the first portion 105 into the case 100 is likely to enter the first light receiving element 16 via the scanning mirror 14 and the transmissive reflecting member 13 along the same path as the first reflected light R1 from the measurement object 200. If the second reflected light R2 that is not reflected by the measurement object 200 enters the first light receiving element 16, it will lead to an erroneous measurement of the distance to the measurement object 200.

[0036] 1, the optical module 10 and the case 100 are arranged such that the optical axis A1 of the light L2 from the scanning mirror 14 is inclined with respect to the first portion 105. As a result, the second optical axis A2 of the second reflected light R2 reflected by the first portion 105 becomes non-parallel to the first optical axis A1 of the light L2 incident on the first portion 105 from the scanning mirror 14, and the second reflected light R2 at the first portion 105 is less likely to return to the scanning mirror 14 via the same path as the first reflected light R1 from the measurement target 200.

[0037] For example, the second optical axis A2 of the second reflected light R2 is inclined with respect to the first optical axis A1 so as to be directed toward the space between the scanning mirror 14 and the transmissive reflecting member 13, and the second reflected light R2 does not return to the reflecting surface 14a of the scanning mirror 14. This makes it possible to prevent the second reflected light R2 reflected by the first portion 105 from being incident on the first light receiving element 16 as stray light that reduces the accuracy of distance measurement.

[0038] In addition, if the second reflected light R2 is reflected multiple times within the case 100, the above-mentioned stray light may occur and enter the first light receiving element 16. For this reason, it is preferable to arrange a low-reflection member at least in the second portion 108 where the second reflected light R2 reflected by the first portion 105 first enters the case 100, or to make the second portion 108 itself a low-reflection member. This makes it possible to suppress multiple reflections of the second reflected light R2 within the case 100 and suppress stray light entering the first light receiving element 16. An example of a low-reflection member is a black member with high light absorptivity.

[0039] [Second embodiment] 3 is a schematic diagram showing the positional relationship between the case 100 and the scanning mirror 14 in the distance measurement device 2 according to the second embodiment of the present invention. Like FIG. 2, FIG. 3 shows a cut surface perpendicular to the central axis C1 of the case 100.

[0040] In the second embodiment, similarly to the first embodiment, the case 100 is cylindrical and includes a first portion 105 on a side surface 103. Also in the second embodiment, the case 100 is configured such that the first reflected light R1 from the measurement target 200 is received by the scanning mirror 14 while the irradiated light L3 is scanned outward from the case 100 by the rotation of the scanning mirror 14. The first portion 105 is continuous along the scanning range of the irradiated light.

[0041] However, in the second embodiment, the scanning mirror 14 is located between the central axis C1 and the side surface 103 of the case 100. In a cross-sectional view perpendicular to the central axis C1 of the case 100 shown in FIG. 3, the scanning mirror 14 is positioned offset from the central axis C1 of the case 100 toward the side surface 103.

[0042] According to such a positional relationship between the scanning mirror 14 and the case 100, in a cross-sectional view perpendicular to the central axis C1 of the case 100 shown in Fig. 3, the light L2 from the scanning mirror 14 is incident at an angle to the first portion 105. Therefore, the second optical axis A2 of the second reflected light R2 reflected by the first portion 105 becomes non-parallel to the first optical axis A1 of the light L2 incident from the scanning mirror 14 to the first portion 105, and the second reflected light R2 at the first portion 105 is unlikely to return to the scanning mirror 14 via the same path as the first reflected light R1 from the measurement target 200. This makes it possible to prevent the second reflected light R2 reflected by the first portion 105 from being incident on the first light receiving element 16 as stray light that reduces the accuracy of distance measurement.

[0043] According to the first embodiment, the first optical axis A1 and the second optical axis A2 are non-parallel to each other within a plane parallel to the central axis C1 of the case 100, as shown in FIG. According to the second embodiment, the first optical axis A1 and the second optical axis A2 are non-parallel to each other within a plane perpendicular to the central axis C1 of the case 100, as shown in FIG.

[0044] It is more preferable to combine the first embodiment and the second embodiment. That is, as shown in FIG. 3, the scanning mirror 14 is positioned between the central axis C1 and the side surface 103 of the case 100. Also, in a cross-sectional view parallel to the central axis C1 at a position on a straight line connecting the scanning mirror 14 and the central axis C1 of the case 100 (cross-sectional view at the position of the dashed line in FIG. 3), the optical axis A1 of the light L2 from the scanning mirror 14 is inclined with respect to the first part 105 of the side surface 103. That is, the first optical axis A1 and the second optical axis A2 are made non-parallel in a plane perpendicular to the central axis C1 of the case 100, and the first optical axis A1 and the second optical axis A2 are also made non-parallel in a plane parallel to the central axis C1 of the case 100. This makes it possible to prevent the occurrence of undesirable reflected light (stray light) that may occur in a certain direction in the case of only the first embodiment or only the second embodiment.

[0045] [Third embodiment] FIG. 4 is a schematic diagram of a distance measurement device 3 according to the third embodiment of the present invention. FIG. 5 is a schematic cross-sectional view taken along line VV in FIG.

[0046] In the third embodiment, the case 100 also has a cylindrical shape including the first portion 106 on the side surface 103. FIG.

[0047] The first portion 106 includes an annular portion 104 located inside the case 100. The annular portion 104 is transparent to the light from the optical module 10 and the reflected light from the measurement target 200, and is made of, for example, resin or glass. As shown in FIG. 5, the annular portion 104 is continuous along the inner circumferential surface of the side surface 103 of the case 100. The annular portion 104 includes an inclined surface 104a inclined with respect to the first optical axis A1 of the light L2 from the scanning mirror 14. The inclined surface 104a is continuous along the scanning range of the irradiated light caused by the rotation of the scanning mirror 14.

[0048] Light L2 from the scanning mirror 14 is incident on the inclined surface 104a. The second optical axis A2 of the second reflected light R2 reflected by the inclined surface 104a is non-parallel to the first optical axis A1 of this light L2. Therefore, the second reflected light R2 from the inclined surface 104a is less likely to return to the scanning mirror 14 along the same path as the first reflected light R1 from the measurement target 200.

[0049] For example, the second optical axis A2 of the second reflected light R2 is inclined with respect to the first optical axis A1 so as to be directed toward the second end face 102 of the case 100, and the second reflected light R2 does not return to the reflecting surface 14a of the scanning mirror 14. This makes it possible to prevent the second reflected light R2 that does not pass through the measurement target 200 from being incident on the first light receiving element 16 as stray light.

[0050] [Fourth embodiment] FIG. 6 is a schematic diagram of a distance measurement device 4 according to the fourth embodiment of the present invention.

[0051] In the fourth embodiment, the case 100 has a truncated cone shape having a first end face 101, a second end face 102, and a side face 103. The side face 103 includes a first portion 105. By making the case 100 into a truncated cone shape, high pressure resistance against water pressure can be obtained, similar to a cylindrical shape. FIG. 6 shows a cross section of the case 100 parallel to a central axis C1 connecting the center of the first end face 101 and the center of the second end face 102.

[0052] In the fourth embodiment, the case 100 is formed into a truncated cone shape, so that the optical axis A1 of the light L2 from the scanning mirror 14 is inclined with respect to the first portion 105 in a cross-sectional view parallel to the central axis C1 of the case 100 shown in Fig. 6. As a result, the second optical axis A2 of the second reflected light R2 reflected by the first portion 105 becomes non-parallel to the first optical axis A1 of the light L2 incident on the first portion 105 from the scanning mirror 14, and the second reflected light R2 at the first portion 105 is less likely to return to the scanning mirror 14 via the same path as the first reflected light R1 from the measurement target 200.

[0053] [Fifth embodiment] FIG. 7 is a schematic diagram showing the positional relationship between the case 110 and the scanning mirror 14 in the distance measurement device 5 according to the fifth embodiment of the present invention.

[0054] In the fifth embodiment, the case 110 is spherical. Fig. 7 shows a cross section perpendicular to the optical axis of the emitted light L1 from the laser light source 11 and passing through the center C2 of the spherical case 110. By making the case 110 spherical, high resistance to water pressure can be obtained. The case 110 can be made of the same material as the case 100 in the above-mentioned embodiment. The spherical surface 113 of the case 110 includes the first portion 107. At least the first portion 107 of the spherical surface 113 of the case 110 has transparency to the light from the optical module 10 and the reflected light from the measurement target 200, and is made of, for example, resin or glass.

[0055] The scanning mirror 14 is located between the center C2 of the case 110 and the spherical surface 113. The scanning mirror 14 is located shifted from the center C2 of the case 110 toward the spherical surface 113. In the fifth embodiment as well, the scanning mirror 14 is configured to receive the first reflected light R1 from the measurement target 200 while scanning the irradiated light L3 toward the outside of the case 110 by the rotation of the scanning mirror 14. The first portion 107 is continuous along the scanning range of the irradiated light.

[0056] By positioning the scanning mirror 14 shifted toward the spherical surface 113 side from the center C2 of the spherical case 110, the light L2 from the scanning mirror 14 is incident at an angle to the first portion 107. Therefore, the second optical axis A2 of the second reflected light R2 reflected by the first portion 107 becomes non-parallel to the first optical axis A1 of the light L2 incident from the scanning mirror 14 to the first portion 107, and the second reflected light R2 from the first portion 107 is unlikely to return to the scanning mirror 14 via the same path as the first reflected light R1 from the measurement target 200. This makes it possible to suppress the second reflected light R2 reflected by the first portion 107 from being incident on the first light receiving element 16 as stray light.

[0057] The above describes the embodiments of the present invention with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that can be implemented by a person skilled in the art through appropriate design modifications based on the above-described embodiments of the present invention also belong to the scope of the present invention as long as they include the gist of the present invention. In addition, within the scope of the concept of the present invention, a person skilled in the art may come up with various modified examples and examples of modifications, and these modified examples and examples of modifications also belong to the scope of the present invention. [Explanation of symbols]

[0058] Reference Signs List 1 to 5: distance measurement device, 10: optical module, 11: laser light source, 12: beam splitter, 13: transmissive reflective member, 14: scanning mirror, 16: first light receiving element, 17: second light receiving element, 100, 110: case, 105 to 107: first portion, 200: measurement object, A1: first optical axis, A2: second optical axis, R1: first reflected light, R2: second reflected light, R3: third reflected light

Claims

1. a case having a first portion formed of a curved surface; an optical module accommodated in the case; Equipped with The optical module includes: A laser light source; A first light receiving element; a scanning mirror that reflects light emitted from the laser light source toward the first portion of the case and receives first reflected light that is the light emitted from the first portion to the outside of the case and reflected by a measurement target; a transmissive reflector disposed between the laser light source and the scanning mirror, transmitting the emitted light from the laser light source toward the scanning mirror and reflecting the first reflected light from the measurement object returning via the scanning mirror toward the first light receiving element; having a first optical axis of light incident on the first portion from the scanning mirror and a second optical axis of a second reflected light incident on the first portion of the case from the scanning mirror and reflected by the first portion are non-parallel; the case has a cylindrical shape including the first portion on a side surface thereof, The scanning mirror is a distance measuring device located between the central axis and the side surface of the case.

2. a case having a first portion formed of a curved surface; an optical module accommodated in the case; Equipped with The optical module includes: A laser light source; A first light receiving element; a scanning mirror that reflects light emitted from the laser light source toward the first portion of the case and receives first reflected light that is the light emitted from the first portion to the outside of the case and reflected by a measurement target; a transmissive reflector disposed between the laser light source and the scanning mirror, transmitting the emitted light from the laser light source toward the scanning mirror and reflecting the first reflected light from the measurement object returning via the scanning mirror toward the first light receiving element; having a first optical axis of light incident on the first portion from the scanning mirror and a second optical axis of a second reflected light incident on the first portion of the case from the scanning mirror and reflected by the first portion are non-parallel; the case is spherical and contains the first portion; The scanning mirror is a distance measuring device located between the center of the case and the first portion.

3. a case having a first portion formed of a curved surface; an optical module accommodated in the case; Equipped with The optical module includes: A laser light source; A first light receiving element; a scanning mirror that reflects light emitted from the laser light source toward the first portion of the case and receives first reflected light that is the light emitted from the first portion to the outside of the case and reflected by a measurement target; a transmissive reflector disposed between the laser light source and the scanning mirror, transmitting the emitted light from the laser light source toward the scanning mirror and reflecting the first reflected light from the measurement object returning via the scanning mirror toward the first light receiving element; having a first optical axis of light incident on the first portion from the scanning mirror and a second optical axis of a second reflected light incident on the first portion of the case from the scanning mirror and reflected by the first portion are non-parallel; The optical module includes: A second light receiving element; a beam splitter disposed between the laser light source and the transmissive reflector, the beam splitter splitting the emitted light from the laser light source into a transmitted light directed toward the transmissive reflector and a third reflected light directed toward the second light receiving element; The distance measuring device further comprises:

4. 4. The distance measurement device according to claim 1, wherein in a cross-sectional view of the case parallel to the light emitted from the laser light source, the first portion of the case onto which the light from the scanning mirror is incident is inclined with respect to the first optical axis.

5. 5. The distance measurement device according to claim 1, wherein the oscillation wavelength of the laser light source is not less than 380 nm and not more than 550 nm.

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