Distance measuring device

Abstract

The present invention relates to a distance measuring device. The distance measuring device (1) includes a mirror module (21) that rotates as a motor (24) is driven. The mirror module includes: a pair of deflection mirrors (211, 212), a mirror support body (213) and a clamp (214, 215). The pair of deflection mirrors have a narrow width portion, which is a portion where the width of the reflection surface along the direction perpendicular to the rotation axis is narrower than other portions of the reflection surface. The mirror support body is a plate-like component having a shape corresponding to the shape of the reflection surface on both sides, and a pair of deflection mirrors are arranged on both sides of the plate-like component. The clamp holds the pair of deflection mirrors and the mirror support body at at least one of the two ends of the portion corresponding to the narrow width portion in the mirror support body in the direction perpendicular to the rotation axis.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority based on Japanese Patent Application No. 2019-108651 filed with the Japan Patent Office on June 11, 2019, and the entire contents of Japanese Patent Application No. 2019-108651 are cited in this international application by reference. Technical Field

[0003] The present disclosure relates to a distance measuring device including a deflecting mirror. Background Art

[0004] There is a distance measuring device that irradiates a transmission wave and detects a reflected wave of the irradiated transmission wave from an object to detect the distance of the object. In this distance measuring device, a deflection mirror that is driven to rotate is used to deflect the transmission wave for scanning, and the output transmission wave is reflected by the deflection mirror and emitted in a direction corresponding to the rotation angle of the deflection mirror, thereby scanning within a preset scanning range.

[0005] Patent Document 1 describes a deflecting mirror device in a laser radar device that deflects light for scanning. The deflecting mirror device includes a pair of deflecting mirrors and a mirror support body, wherein the pair of deflecting mirrors are provided on opposite sides of the mirror support body.

[0006] Patent Document 1: Japanese Patent Application No. 2018-500603

[0007] As a result of detailed studies, the inventors have found that, in a distance measuring device including a mirror module having a pair of deflecting mirrors and a mirror support body, it is desirable to facilitate the assembly of the deflecting mirrors and the mirror support body and to reduce the size of the entire mirror module. Summary of the invention

[0008] One aspect of the present disclosure is to provide a technology that facilitates the assembly of a deflection mirror and a mirror support body and reduces the size of the entire mirror module.

[0009] One method disclosed herein is a distance measuring device, comprising a mirror module that rotates as a motor is driven. The mirror module comprises: a pair of deflecting mirrors, a mirror support body, and a clamp. The pair of deflecting mirrors have a narrow width portion, which is a portion where the width of the reflecting surface along the direction perpendicular to the rotation axis is narrower than other portions of the reflecting surface. The mirror support body is a plate-like component having shapes corresponding to the shapes of the reflecting surface on both sides, and a pair of deflecting mirrors are provided on both sides of the plate-like component. The clamp holds the pair of deflecting mirrors and the mirror support body at at least one of the two end portions of the portion corresponding to the narrow width portion in the mirror support body in the direction perpendicular to the rotation axis.

[0010] According to such a structure, the pair of deflecting mirrors and the mirror support body can be easily assembled by clamping and supporting them with a clamp. In addition, when the clamp is provided, the outer dimensions of the entire mirror module increase by the amount of the clamp extending from the deflecting mirror. However, by providing the clamp in the narrow width portion, the increase in the outer dimensions of the entire mirror module can be reduced.

[0011] In this way, the deflecting mirror and the mirror support body can be easily assembled, and the size of the entire mirror module can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a stereoscopic diagram showing the appearance of a laser radar device.

[0013] Figure 2 This is an exploded perspective view of a laser radar device.

[0014] Figure 3 It is a three-dimensional diagram showing the structure of a light detection module housed in a housing of a laser radar device.

[0015] Figure 4 This is an exploded perspective view of the mirror module and the partition plate in the scanning unit.

[0016] Figure 5 This is a diagram of the mirror module viewed from the reflective surface side of a deflection mirror. DETAILED DESCRIPTION

[0017] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.

[0018] [1.Structure]

[0019] Figure 1 The laser radar device 1 shown is a distance measuring device that emits light and receives its reflected light to measure the distance to an object. The laser radar device 1 is mounted on a vehicle and used to detect various objects in front of the vehicle. Laser radar is also recorded as LIDAR. LIDAR is the abbreviation of Light Detection and Ranging.

[0020] like Figure 1 As shown, the laser radar device 1 includes a housing 100 and an optical window 200. The housing 100 is a box made of resin and formed in a rectangular parallelepiped shape with one surface opened.

[0021] Hereinafter, the direction along the long side of the opening of the housing 100 having a substantially rectangular shape is defined as the X-axis direction, the direction along the short side of the opening is defined as the Y-axis direction, and the direction orthogonal to the X-Y plane is defined as the Z-axis direction. In addition, when the laser radar device 1 is installed on the vehicle in a manner that the X-Z plane is horizontal and viewed from the opening side of the housing 100, the left and right in the X-axis direction and the top and bottom in the Y-axis direction are defined. In addition, with respect to the front and back in the Z-axis direction, the opening side of the housing 100 is defined as the front, and the depth side is defined as the back.

[0022] like Figure 2 As shown, the light detection module 2 is housed inside the housing 100 . The light detection module 2 includes a light projecting unit 10 , a scanning unit 20 , and a light receiving unit 30 .

[0023] Hereinafter, the structure of the photodetection module 2 , particularly the structure of the mirror module 21 , will be described in detail.

[0024] [2. Scanning unit]

[0025] like Figure 3 as well as Figure 4 As shown, the scanning unit 20 includes a mirror module 21, a pair of partition plates 22, 23 and a motor 24. The mirror module 21 is vertically arranged on the motor 24. The mirror module 21 and the pair of partition plates 22, 23 fixed to the mirror module 21 are Figure 5 The motor 24 is driven to rotate the rotating shaft centered on the rotating shaft indicated by the dot-dash line.

[0026] [3. Mirror module and partition plate]

[0027] The mirror module 21 includes a pair of deflecting mirrors 211 and 212 , a mirror support 213 , and a pair of clamps 214 and 215 .

[0028] Each of the pair of deflecting mirrors 211 and 212 is a flat plate-shaped member having a reflecting surface for reflecting light.

[0029] The mirror support body 213 includes a circular plate portion 213a and a mounted portion 213b. The circular plate portion 213a is a circular plate-shaped portion, the center of which is fixed to the rotation axis of the motor 24. The mounted portion 213b is a plate-shaped portion having a pair of deflection mirrors 211 and 212 disposed on both sides, and is vertically disposed on the circular surface of the circular plate portion 213a.

[0030] The pair of deflecting mirrors 211 and 212 has a shape in which two rectangles having different widths in the long-side direction are integrated. Specifically, the pair of deflecting mirrors 211 and 212 has a shape in which a first rectangle and a second rectangle having a width in the long-side direction longer than the first rectangle are aligned along the central axis in the short-side direction of each rectangle and arranged along the central axis for integration. Hereinafter, in the pair of deflecting mirrors 211 and 212, the portion corresponding to the first rectangle is referred to as a narrow width portion, and the portion corresponding to the second rectangle is referred to as a wide width portion.

[0031] The shape of the installation surface of the pair of deflection mirrors 211 and 212 in the installation portion 213b corresponds to the shape of the pair of deflection mirrors 211 and 212. The installation portion 213b includes a pair of guides 216 and 217 on both side surfaces sandwiching the rotation axis in the portion corresponding to the narrow width portion.

[0032] The pair of guides 216 and 217 are protrusions protruding from the side surfaces on both sides of the rotation axis in the portion corresponding to the narrow width portion of the set portion 213b toward the pair of deflection mirrors 211 and 212. The pair of guides 216 and 217 contact the pair of deflection mirrors 211 and 212 on both sides of the direction perpendicular to the rotation axis in the narrow width portion, and restrict the movement of the pair of deflection mirrors 211 and 212 in the direction perpendicular to the rotation axis in the reflection surface.

[0033] like Figure 4 As shown, the clamp 214 has a U-shaped shape including a base 214a and a pair of holding portions 214b and 214c extending from the base 214a. The clamp 214 holds the pair of deflection mirrors 211 and 212 and the set portion 213b at the end portions in the direction perpendicular to the rotation axis in the narrow width portion of the pair of deflection mirrors 211 and 212 by the pair of holding portions 214b and 214c. The clamp 215 has a base 215a and a pair of holding portions 215b and 215c extending from the base 215a, and has the same shape as the clamp 214. The clamp 215 is set at the end portion on the opposite side of the clamp 214 among the two end portions in the direction perpendicular to the rotation axis in the narrow width portion of the pair of deflection mirrors 211 and 212.

[0034] exist Figure 5 , the pair of deflection mirrors 211, 212 and the installation portion 213b are shown being held by the pair of clamps 214, 215. The pair of clamps 214, 215 and the pair of guides 216, 217 are located inside the width of the wide portions of the pair of deflection mirrors 211, 212 in the longitudinal direction.

[0035] like Figure 4As shown, the pair of partition plates 22 and 23 are plates that divide a circular plate-shaped member having the same diameter as the width in the long-side direction of the wide width portion of the pair of deflection mirrors 211 and 212 into two semicircular portions. The pair of partition plates 22 and 23 are fixed to the mirror module 21 in a state where they sandwich the narrow width portions of the pair of deflection mirrors 211 and 212 from both sides and abut against the step portions between the wide width portions and the narrow width portions of the pair of deflection mirrors 211 and 212.

[0036] The following, such as Figure 3 as well as Figure 5 As shown, the portion of the pair of deflecting mirrors 211 and 212 that is above the pair of partition plates 22 and 23, that is, the portion on the narrow width side is called the light projection deflection unit 20a. In addition, the portion of the pair of deflecting mirrors 211 and 212 that is below the pair of partition plates 22 and 23, that is, the portion on the wide width side is called the light receiving deflection unit 20b.

[0037] [4.Light projection part]

[0038] like Figure 3 As shown, the light projecting unit 10 includes a pair of light emitting modules 11 and 12. The light projecting unit 10 may include a light projection reflecting mirror 15.

[0039] The light emitting module 11 includes a light source 111 and a light emitting lens 112, which are arranged opposite to each other. The light source 111 uses a semiconductor laser. The light emitting lens 112 is a lens that narrows the beam width of the light emitted from the light source 111. Similarly, the light emitting module 12 includes a light source 121 and a light emitting lens 122. Since the light emitting module 12 is the same as the light emitting module 11, the description thereof is omitted.

[0040] The light projection and reflection mirror 15 is a mirror that changes the traveling direction of light.

[0041] The light emitting module 11 is arranged so that light output from the light emitting module 11 directly enters the light projection and deflection unit 20 a .

[0042] The light emitting module 12 is arranged so that the traveling direction of light outputted from the light emitting module 12 is bent by approximately 90 degrees by the light projection return mirror 15 and the light is incident on the light projection deflection unit 20 a .

[0043] Here, the light emitting module 11 is configured to output light from left to right in the X-axis direction, and the light emitting module 12 is configured to output light from back to front in the Z-axis direction. In addition, the light reflection mirror 15 is configured not to block the path of light from the light emitting module 11 toward the light projection deflection unit 20a.

[0044] [5. Light receiving part]

[0045] The light receiving unit 30 includes a light receiving element 31. The light receiving unit 30 may include a light receiving lens 32 and a light receiving reflecting mirror 33.

[0046] The light receiving element 31 has an APD array in which a plurality of APDs are arranged in a row. APD is an avalanche photodiode.

[0047] The light receiving lens 32 is a lens that reduces the light received from the light receiving deflection unit 20 b .

[0048] The light receiving reflection mirror 33 is disposed on the left side of the light receiving lens 32 in the X-axis direction and is a mirror that changes the traveling direction of light. The light receiving element 31 is disposed below the light receiving reflection mirror 33 .

[0049] The light receiving reflection mirror 33 is arranged to bend the path of light downward by approximately 90 degrees so that light incident from the light receiving deflection unit 20 b via the light receiving lens 32 reaches the light receiving element 31 .

[0050] The light receiving lens 32 is disposed between the light receiving deflection unit 20b and the light receiving folding mirror 33. The light receiving lens 32 focuses the light beam incident on the light receiving element 31 so that the beam diameter thereof becomes approximately equal to the element width of the APD.

[0051] [6. Operation of the light detection module]

[0052] The light output from the light emitting module 11 is incident on the light projection deflection unit 20a. In addition, the traveling direction of the light output from the light emitting module 12 is bent by approximately 90° by the light projection return mirror 15 and is incident on the light projection deflection unit 20a. The light incident on the light projection deflection unit 20a is emitted in a direction corresponding to the rotation angle of the mirror module 21 via the optical window 200. The range of light irradiated via the mirror module 21 is the scanning range. For example, the forward direction along the Z axis is set to 0 degrees, and the range of ±60° extending along the X axis direction can be set as the scanning range.

[0053] The reflected light from the object under test located in a predetermined direction corresponding to the rotation position of the mirror module 21, i.e., in the emission direction of the light from the projecting light deflection unit 20a, passes through the optical window 200 and is reflected by the receiving light deflection unit 20b. Thereafter, the reflected light is received by the light receiving element 31 via the light receiving lens 32 and the light receiving folding mirror 33.

[0054] [7. Effect]

[0055] According to the above-described detailed embodiments, the following effects are obtained.

[0056] (7a) In the laser radar device 1, the pair of deflection mirrors 211, 212 and the mirror support body 213 are held by the clamps 214, 215 at both ends of the narrow width portion of the pair of deflection mirrors 211, 212 in the direction perpendicular to the rotation axis. According to such a structure, the pair of deflection mirrors 211, 212 and the mirror support body 213 can be easily assembled by clamping and supporting them with the clamps 214, 215. In addition, by providing the clamps 214, 215 in the narrow width portion as in the present embodiment, the protrusion of the clamps from the deflection mirrors can be reduced, thereby reducing the increase in the outer dimensions of the entire mirror module 21 and miniaturizing the size of the entire mirror module 21.

[0057] (7b) In the laser radar device 1, the installation portion 213b of the mirror support body 213 is provided with a pair of guides 216 and 217, which are protrusions protruding from the side surfaces on both sides of the rotation axis in the portion corresponding to the narrow width portion toward the pair of deflection mirrors 211 and 212. The pair of guides 216 and 217 restrict the movement of the pair of deflection mirrors 211 and 212 in the direction perpendicular to the rotation axis in the reflection surface. According to such a structure, it is possible to suppress the pair of deflection mirrors 211 and 212 from deviating in the direction perpendicular to the rotation axis in the reflection surface, so that the assembly of the pair of deflection mirrors 211 and 212 and the mirror support body 213 can be made easier. In addition, by providing the pair of guides 216 and 217 in the portion corresponding to the narrow width portion of the installation portion 213b, it is possible to reduce the increase in the outer dimensions of the mirror module 21 as a whole, so that the size of the mirror module 21 as a whole can be miniaturized.

[0058] (7c) In the laser radar device 1, the narrow width portion of the pair of deflection mirrors 211 and 212 is formed on either side of the reflection surface in the direction parallel to the rotation axis. The pair of deflection mirrors 211 and 212 are formed by aligning a first rectangle and a second rectangle whose width in the long side direction is longer than that of the first rectangle along the central axis of the short side direction of each rectangle, and arranging and integrating them along the central axis, and the portion corresponding to the first rectangle is the narrow width portion. In this way, the shape of the pair of deflection mirrors 211 and 212 can be simplified, so that the pair of deflection mirrors 211 and 21 and the mirror support body 213 can be easily manufactured, and their assembly can also be made easier.

[0059] In addition, in the laser radar device 1, the light beam output from the light projecting unit 10 and incident on the light projecting deflection unit 20a is in a point shape, and is reflected near the center of the light projecting deflection unit 20a and emitted. In contrast, the light beam of the reflected light from the object to be inspected has expansion properties, is reflected by the entire light receiving deflection unit 20b, and the beam diameter is reduced by the light receiving lens 32 to become a width suitable for incident on the light receiving element 31. Therefore, even if the width of the light projecting deflection unit 20a is reduced, the influence on the emitted light is small, but if the width of the light receiving deflection unit 20b is reduced, the amount of reflected light is reduced, so it may be difficult to detect the reflected light.

[0060] In this embodiment, since the narrow width portion is formed in the projection light deflection unit 20a, the influence on the distance measurement accuracy is small. In addition, the occurrence of ghosts caused by the transmission wave being reflected in a direction different from the original reflection direction at the end of the projection light deflection unit 20a can be reduced.

[0061] In the present embodiment, the light projecting unit 10 corresponds to a transmitting unit, the light receiving unit 30 corresponds to a receiving unit, the light projecting deflecting unit 20 a corresponds to a transmitting deflecting unit, and the light receiving deflecting unit 20 b corresponds to a receiving deflecting unit.

[0062] [8. Other embodiments]

[0063] As mentioned above, although embodiment of this disclosure was described, this disclosure is not limited to the said embodiment, Of course, various forms can be adopted.

[0064] (8a) In the above embodiment, an example is proposed in which the pair of deflection mirrors 211, 212 and the mirror support body 213 are gripped by the clamps 214, 215 at both ends of the narrow width portion of the pair of deflection mirrors 211, 212 in the direction perpendicular to the rotation axis. However, the pair of deflection mirrors 211, 212 and the mirror support body 213 may be gripped by the clamp at one end.

[0065] (8b) In the above embodiment, all of the pair of clamps 214, 215 and the pair of guides 216, 217 are located inside the width of the wide portion of the pair of deflecting mirrors 211, 212 in the long-side direction. However, a portion of the pair of clamps 214, 215 and the pair of guides 216, 217 may protrude outside the width of the wide portion in the long-side direction.

[0066] (8c) In the above embodiment, the pair of deflection mirrors 211 and 212 are formed in a shape in which a first rectangle and a second rectangle whose width in the long side direction is longer than that of the first rectangle are aligned along the central axis in the short side direction of each rectangle, and are arranged along the central axis to be integrated. However, the shape of the pair of deflection mirrors 211 and 212 is not limited to the above shape as long as it has a narrow width portion. For example, the pair of deflection mirrors 211 and 212 may also have a shape in which a narrow width portion is sandwiched between wide width portions.

[0067] (8d) In the above embodiment, the portion of the pair of deflecting mirrors 211 and 212 that is above the pair of partition plates 22 and 23 is the light-projecting deflection unit 20a, and the portion that is below is the light-receiving deflection unit 20b. However, the laser radar device 1 may be configured such that the portion above is the light-receiving deflection unit 20b, and the portion below is the light-projecting deflection unit 20a.

[0068] (8e) In the above embodiment, the laser radar device 1 is exemplified as the distance measuring device, but the type of the distance measuring device is not limited to this. For example, the distance measuring device may be a millimeter wave radar device or the like.

[0069] (8f) The function of one component in the above-mentioned embodiment can be dispersed into multiple components, or the functions of multiple components can be integrated into one component. In addition, a part of the structure of the above-mentioned embodiment can be omitted. In addition, at least a part of the structure of the above-mentioned embodiment can be added to or replaced by the structure of other above-mentioned embodiments.

Claims

1. A distance measuring device, wherein: Equipped with a mirror module, it rotates as the motor drives it. The mirror module has: A pair of deflecting mirrors having a narrow width portion, wherein the narrow width portion is a portion of the reflecting surface having a width along a direction perpendicular to the rotation axis narrower than other portions of the reflecting surface; The mirror support is a plate-like member having shapes corresponding to the shapes of the above-mentioned reflecting surface on both surfaces, and the above-mentioned pair of deflecting mirrors are arranged on both surfaces of the above-mentioned plate-like member; as well as a clamp that holds the pair of deflecting mirrors and the mirror support body at at least one of the two ends of a portion of the mirror support body corresponding to the narrow width portion in a direction perpendicular to the rotation axis, The mirror support body includes at least one pair of guides, which are protrusions provided on the side surfaces of a portion of the mirror support body corresponding to the narrow width portion and are protrusions that restrict the positions of the pair of deflecting mirrors on both sides of the narrow width portion in a direction orthogonal to the rotation axis.

2. The distance measuring device according to claim 1, wherein: Also available: a transmitting unit configured to output a transmission wave; and a receiving unit configured to detect a reflected wave from an object irradiated with the transmission wave, The narrow width portion is formed on either side of the pair of deflecting mirrors in a direction parallel to the rotation axis. The pair of deflecting mirrors includes two parts, namely, a transmission deflection part located on the transmission part side and a reception deflection part located on the reception part side, and the narrow width part is formed in the transmission deflection part.

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