Optical Displacement Meter

Abstract

To measure displacement in an entire rotational angle of a light projection / reception system even if a reading area of an image sensor is narrowed down in an optical displacement gauge for measuring displacement by rotating the light projection / reception system.SOLUTION: An optical displacement gauge 1 includes: a light projection section for applying slit beams extending in the X direction; an image sensor for receiving light condensed by a light receiving lens; a light projection / reception module for integrally holding the light projection section, the light receiving lens, and the image sensor; a motor for rotating the light projection / reception module; a control section for controlling the motor, rotating the light projection / reception module, and performing scanning of slit beams in a direction orthogonal to the X direction; and an arithmetic section for generating a sectional profile showing a height in the Z direction on the basis of a pixel signal read from the image sensor in each of different positions in a scanning direction. The arithmetic section is configured so as to be capable of changing a partial area as an object for reading a pixel signal of the image sensor according to a rotational angle.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present disclosure relates to an optical displacement meter that uses light to measure the displacement of a workpiece. [Background technology]

[0002] One known optical displacement meter is configured to acquire an XZ cross-sectional profile by irradiating a workpiece with a slit light extending in the X direction and receiving the light reflected by the workpiece surface with an image sensor. By acquiring multiple XZ cross-sectional profiles at different positions in the Y direction of the workpiece, it is possible to generate data on the three-dimensional shape of the workpiece, but this requires equipment such as a conveyor to transport the workpiece in the Y direction and a linear motion mechanism to move the displacement meter body in the Y direction relative to the workpiece, which can be difficult to implement.

[0003] In response to this, for example, as in Patent Documents 1 and 2, a structure is known in which a light-projecting system that projects slit light and a light-receiving system that receives reflected light (collectively referred to as the light-projecting and receiving system) are configured to be rotatable, and the light-projecting and receiving system is rotated so that the slit light is scanned in the Y direction relative to the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent Publication No. 3232152 [Patent Document 2] China Utility Model Registration No. 210664364 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when measuring parts of the workpiece at the same height using a linear motion mechanism to move the displacement gauge body in the Y direction relative to the workpiece, the peak position in the V direction (the direction corresponding to the Z direction of the workpiece) on the image sensor will be the same even for multiple XZ cross-sectional profiles obtained at different positions in the Y direction of the workpiece. In this case, it is possible to speed up measurements by narrowing the readout area of ​​the image sensor to the part corresponding to the height range of the workpiece.

[0006] However, when acquiring multiple cross-sectional profiles by rotating the light projecting and receiving system relative to a stationary workpiece as in Patent Documents 1 and 2, the measurement area is arc-shaped around the rotation axis. As a result, even for parts of the workpiece at the same height, the peak position in the V direction of each profile changes depending on the rotation angle of the light projecting and receiving system. Therefore, if the readout area of ​​the image sensor is fixed in an attempt to increase the measurement speed, there is a problem in that it becomes impossible to measure displacement over the entire rotation angle of the light projecting and receiving system.

[0007] The present disclosure has been made in consideration of such points, and its purpose is to enable, in an optical displacement meter that measures displacement by rotating a light projecting and receiving system, measurement of displacement over the entire rotation angle of the light projecting and receiving system even when the readout area of ​​the image sensor is narrowed. [Means for solving the problem]

[0008] In order to achieve the above object, this aspect can be premised on an optical displacement meter that measures the displacement of a workpiece using light. The optical displacement meter is an optical displacement meter of a light-cutting type that measures the cross-sectional profile of a workpiece having a height in the Z direction based on the principle of triangulation. The optical displacement meter includes an imaging unit having a light-projecting unit that irradiates the workpiece with a slit light extending in the X direction, a light-receiving lens that collects the reflected light reflected by the workpiece, an image sensor that receives the reflected light collected by the light-receiving lens, and an imaging control unit that controls the image sensor, a motor that integrally rotates a light-projecting and receiving module that includes the light-projecting unit, the light-receiving lens, and the imaging unit, a control unit that controls the motor to scan the slit light in a direction perpendicular to the X direction, and a signal processing unit that generates the cross-sectional profile at each rotation angle of the motor based on the amount of light received by the image sensor. The rotation of the light-projecting and receiving module forms a substantially arc-shaped measurable range having a predetermined depth around the rotation axis of the imaging unit, and the imaging control unit dynamically changes a partial area from which the amount of light received by the image sensor is read out according to each rotation angle, corresponding to a measurement range that differs depending on each rotation angle.

[0009] With this configuration, when the light-emitting and receiving modules are rotated integrally by a motor, a slit light extending in the X direction scans the workpiece in a direction perpendicular to the X direction, forming a roughly arc-shaped measurable range with a predetermined depth around the center of the rotation axis of the imaging unit. If a partial region from which the amount of received light is read is set rather than reading the amount of received light from the entire imaging unit to increase speed, the measurement range varies depending on the rotation angle, and different heights (Z direction) of the workpiece are imaged even in the same partial region. Therefore, by dynamically changing the partial region according to each rotation angle, different measurement ranges are assigned to each rotation angle, making it possible to acquire multiple cross-sectional profiles at different positions on the workpiece and generate three-dimensional shape data of the workpiece at high speed, without requiring equipment such as a conveyor for transporting the workpiece in the Y direction or a linear motion mechanism for moving the displacement gauge body in the Y direction relative to the workpiece. [Effects of the Invention]

[0010] As described above, the partial area from which pixel signals of the image sensor are read out can be changed depending on the rotation angle of the light projecting unit, the light receiving lens, and the image sensor. Therefore, even when the readout area of ​​the image sensor is narrowed in order to speed up measurement, displacement can be measured over the entire rotation angle of the light projecting and receiving system. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram illustrating an optical displacement meter according to the first embodiment of the present invention during operation. [Figure 2] 1 is a perspective view of an optical displacement meter according to a first embodiment of the present invention, as seen from above. [Figure 3] 1 is a perspective view of an optical displacement meter according to a first embodiment of the present invention, as viewed from below. [Figure 4] 1 is a plan view showing the inside of an upper space of an optical displacement meter according to a first embodiment of the present invention. [Figure 5] 1 is a plan view of a light emitting and receiving module of an optical displacement meter according to a first embodiment of the present invention. [Figure 6] 1 is a block diagram showing the configuration of an optical displacement meter according to a first embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 2. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 2. [Figure 9] FIG. 10 is a diagram illustrating a displacement measurement technique. [Figure 10] 10A and 10B are diagrams illustrating an example of measuring the displacement of a workpiece whose surfaces are at the same height. [Figure 11] 10A and 10B are diagrams illustrating an example in which the position of a partial region on an image sensor is changed in the V direction. [Figure 12] 10A and 10B are diagrams illustrating an example of measuring the displacement of a workpiece whose surface height varies depending on the part. [Figure 13] FIG. 6 is a view corresponding to FIG. 5 according to a first modified example of the first embodiment. [Figure 14] 4 according to a second modification of the first embodiment. FIG. [Figure 15] 10 is a diagram showing the internal structure of an optical displacement meter according to a second modification of the first embodiment, viewed from below. FIG. [Figure 16] FIG. 10 is a view corresponding to FIG. 2 according to the second embodiment. [Figure 17] FIG. 10 is a diagram showing the internal structure of the optical displacement meter according to the second embodiment as viewed from above. [Figure 18] FIG. 8 is a view corresponding to FIG. 7 according to the second embodiment. [Figure 19] FIG. 17 is a view according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0013] (Embodiment 1) 1 is a diagram illustrating an optical displacement meter 1 according to a first embodiment of the present invention during operation. The optical displacement meter 1 is an example of a light-cutting type optical displacement meter that uses a slit light S1 to measure a cross-sectional profile of a workpiece W (measurement object) having a height in the Z direction based on the principle of triangulation. In this embodiment, an example will be described in which an inspection system S is configured by the optical displacement meter 1, a controller 2, and a personal computer PC, but the present invention is not limited to this configuration example, and the inspection system S may also include, for example, a PLC (programmable logic controller) or the like.

[0014] When setting up the inspection system S before it is put into operation, various inspection settings can be made using, for example, the controller 2 and personal computer PC. When it is put into operation after setting up, the optical displacement meter 1 measures the displacement of the workpiece W at a predetermined timing. Data indicating the measurement results is sent from the optical displacement meter 1 to the controller 2 and personal computer PC, and an inspection based on the inspection settings is carried out. Data indicating the measurement results of the optical displacement meter 1, the inspection results, etc. can be saved in the controller 2 and personal computer PC.

[0015] During operation, it is possible to operate using only the optical displacement meter 1 without using the controller 2 and personal computer PC, and the operation is not limited to the form of operation shown in Fig. 1. In the following explanation, an inspection system S including the optical displacement meter 1 is described, but the present invention is also applicable to cases where the system is operated using only the optical displacement meter 1, or where the system is operated in combination with a PLC.

[0016] The inspection system S is a system that performs in-line visual inspection of the workpiece W. In in-line visual inspection, for example, the visual inspection of the workpiece W is performed sequentially at a site where multiple workpieces W are being transported sequentially. The X, Y, and Z directions of the workpiece W are defined as shown in Figure 1. In a plan view of the workpiece W, the X and Y directions are directions that are perpendicular to each other. The Z direction is the height direction of the workpiece W, and is a direction that is perpendicular to the X direction and perpendicular to the Y direction. The X direction of the workpiece W can also be called the depth direction of the workpiece W, and the Y direction of the workpiece W can also be called the width direction of the workpiece W, but this definition is an example, and the definitions of the X, Y, and Z directions of the workpiece W are arbitrary.

[0017] Since the optical displacement meter 1 can acquire height data of the workpiece W, the appearance inspection includes dimensional inspection, shape inspection, defect inspection, etc. based on the height data. The workpiece W is not particularly limited, and examples include various parts, components, devices, instruments, and parts thereof. The workpiece W can also be called the measurement object. After the workpiece W is transported to the measurable area of ​​the optical displacement meter 1 by a transport device (not shown), the optical displacement meter 1 measures the displacement.

[0018] The optical displacement meter 1 is used while being fixed to, for example, a mounting member 5. The mounting member 5 is part of equipment installed in a factory or the like, and is fixed so as not to move relative to the workpiece W. Therefore, the optical displacement meter 1 also does not move relative to the workpiece W. As will be described in detail later, even if the optical displacement meter 1 is fixed to the mounting member 5, by making the internal light-emitting and receiving module 10 (shown in FIG. 4) rotatable about an axis parallel to the X direction, it is possible to scan the slit light S1 extending in the X direction of the workpiece W from the light-emitting and receiving module 10 in a direction perpendicular to the X direction of the workpiece W, and receive the reflected light S2 reflected at multiple points in the Y direction on the surface W1 of the workpiece W by the light-emitting and receiving module 10. In this way, even when the light-emitting and receiving module 10 is rotated about an axis parallel to the X direction, the slit light S1 can be scanned over the surface W1 of the workpiece W, just as when the workpiece W or the optical displacement meter 1 is moved linearly. In addition, since the optical displacement meter 1 scans the slit light S1 by rotating the light emitting / receiving module 10, the scanning direction of the slit light S1 is a direction perpendicular to the X direction in the YZ plane, which includes the Y direction. In this specification, "rotation" means a swinging motion that goes back and forth around a rotation axis.

[0019] By performing signal processing based on the amount of received reflected light S2, multiple cross-sectional profiles of the workpiece W at different rotation angles can be obtained. Based on the obtained cross-sectional profiles, it is possible to generate data (height data) on the three-dimensional shape of the workpiece W. Note that because the slit light S1 rotates, the cross-sectional profiles are not necessarily parallel to the XZ plane.

[0020] As described above, by making the light emitting and receiving module 10 provided inside the optical displacement meter 1 rotatable, it is possible to acquire multiple cross-sectional profiles of the workpiece W at different rotation angles without transporting the workpiece W in the Y direction or moving the optical displacement meter 1 in the Y direction relative to the workpiece W. Therefore, there is no need for equipment such as a conveyor for transporting the workpiece W or a linear motion mechanism for moving the optical displacement meter 1 in the Y direction relative to the workpiece W, making it easier to introduce an inspection process using the optical displacement meter 1.

[0021] The workpiece W may be movable relative to the optical displacement meter 1, but multiple cross-sectional profiles can be acquired with the workpiece W stopped during measurement. The optical displacement meter 1 may be movable relative to the workpiece W, but multiple cross-sectional profiles can be acquired with the optical displacement meter 1 stopped during measurement. The present invention is not limited to cases where the optical displacement meter 1 is completely fixed, but it may be movably supported on the mounting member 5, or may be attached to a robot arm or the like and movable to any measurement location.

[0022] FIG. 2 is a perspective view of the optical displacement meter 1 according to the first embodiment of the present invention, as seen from above, and FIG. 3 is a perspective view of the optical displacement meter 1 according to the first embodiment of the present invention, as seen from below. As shown in each figure, the left-right direction, depth direction, and up-down direction of the optical displacement meter 1 are defined, but this is for the sake of convenience of explanation and does not limit the orientation of the optical displacement meter 1 during operation. In the operating configuration shown in FIG. 1, the optical displacement meter 1 is installed above the workpiece W, so that the slit light S1 is emitted downward and the reflected light S2 travels upward. In this operating configuration, the left-right direction of the optical displacement meter 1 corresponds to the Y direction of the workpiece W, the up-down direction of the optical displacement meter 1 corresponds to the X direction of the workpiece W, and the depth direction of the optical displacement meter 1 corresponds to the Z direction of the workpiece W. Furthermore, the optical displacement meter 1 may be installed so that the slit light S1 is irradiated horizontally onto the workpiece W, or so that the slit light S1 is irradiated downward onto the workpiece W, and the orientation of the optical displacement meter 1 when installed is not particularly limited.

[0023] FIG. 4 is a diagram showing the internal structure of the optical displacement meter 1. The optical displacement meter 1 includes a light emitting and receiving module 10 (also shown in FIG. 5), a motor 20 (shown in FIG. 7) for rotating the light emitting and receiving module 10, a motor control unit 30 (shown in FIG. 8), and a housing 40. The light emitting and receiving module 10, the motor 20, and the motor control unit 30 are housed in the housing 40. As shown in FIG. 6, in this embodiment 1, the control unit 3 is made up of the motor control unit 30, a power supply unit 34 (described later), and a signal processing unit 32 (described later). Note that, for convenience of explanation, the motor control unit 30 and the signal processing unit 32 are shown separately in FIG. 6, but the motor control unit 30 and the signal processing unit 32 may be integrated.

[0024] The light-emitting / receiving module 10 includes a light-emitting unit 11 that emits slit light S1 extending in the X direction, a light-collecting unit 12 that has a light-receiving lens that collects reflected light S2 reflected by the workpiece W, an imaging unit 13 that receives the light collected by the light-collecting unit 12, and a support member 14 that holds the light-emitting unit 11, the light-collecting unit 12, and the imaging unit 13 together.

[0025] As shown in FIG. 6, the light-projecting unit 11 includes a laser beam emitter (light source) 11a, an optical system 11b, a light source housing that houses the laser beam emitter 11a and the optical system 11b, and a light-projection control unit 11c that controls the laser beam emitter 11a. The laser beam emitter 11a is controlled by the light-projection control unit 11c to emit a predetermined amount of laser beam at a predetermined timing for a predetermined period of time. The light emitted from the laser beam emitter 11a is incident on the optical system 11b. The optical system 11b is composed of multiple lenses, including, for example, cylindrical lenses (not shown), and spreads the incident laser beam into a strip-like shape to form a slit beam S1, which is then irradiated onto the workpiece W. The light-projecting unit 11 is elongated in the direction of irradiation of the slit beam S1.

[0026] In order to improve the amount of received light, light collecting unit 12 is configured as a lens unit including multiple large-diameter light-receiving lenses, and has the light-receiving lenses and a lens housing that houses the light-receiving lenses. Because it includes multiple large-diameter lenses and is relatively large in size, the weight of light collecting unit 12 is heavier than the weight of light projecting unit 11.

[0027] The imaging unit 13 has an image sensor 13a such as a CMOS (complementary metal oxide semiconductor) and an imaging control unit 13b. The image sensor 13a is controlled by the imaging control unit 13b to capture an image at a predetermined timing. The exposure time of the image sensor 13a when capturing an image can be controlled by the imaging control unit 13b.

[0028] 7 and 8, the support member 14 is made of a flat, highly rigid member, such as a metal plate. As shown in Fig. 7, the support member 14 is fixed to a rotation shaft 50 that constitutes a part of the optical displacement meter 1, and is supported by the housing 40 so as to be rotatable around a rotation center line A that is the axial core of the rotation shaft 50. The extension direction of the support member 14 is perpendicular to the rotation center line A.

[0029] The light projecting unit 11, the light collecting unit 12, and the imaging unit 13 are fixed to the upper surface of the support member 14. Specifically, in a plan view of the light projecting and receiving module 10 shown in Fig. 5, the light projecting unit 11 is fixed to a portion of the support member 14 to the left of the rotation center line A, and the light collecting unit 12 and the imaging unit 13 are fixed to the opposite side. As a result, the light projecting unit 11 and the light collecting unit 12 are provided at intervals from each other in the radial directions (Y direction and Z direction) of the rotation axis 50.

[0030] The light-projecting unit 11 is disposed so that the irradiation direction of the slit light S1 faces the Z direction. The light-collecting unit 12 is disposed on the front side (workpiece W side) of the support member 14 so that its optical axis is aligned with the direction in which the reflected light S2 is incident. Therefore, both the light-projecting unit 11 and the light-collecting unit 12 face the Z direction, but the optical axis of the optical system 11b of the light-projecting unit 11 and the optical axis of the light-collecting unit 12 (the optical axis of the light-receiving lens) intersect with each other at a location away from the light-projecting and receiving module 10 in the Z direction. The horizontal distance between the light-projecting unit 11 and the light-collecting unit 12, and the relationship between the optical axis of the optical system 11b of the light-projecting unit 11 and the optical axis of the light-collecting unit 12 can be changed depending on the installation distance of the optical displacement meter 1 from the workpiece W, the measurement accuracy, etc., and therefore the illustrated example is merely an example.

[0031] The longer the distance between the light-collecting unit 12 and the rotation axis, the greater the moment of inertia of the light-collecting unit 12 due to rotation. When switching the rotation direction of the light-emitting / receiving module 20, the light-emitting / receiving module 20 must be stopped temporarily. In this case, the greater the moment of inertia, the greater the energy required to decelerate the rotational motion of the light-emitting / receiving module 20, leading to an increase in the distance and time required to stop the rotational motion. Therefore, the light-emitting / receiving module 10 further includes a light-receiving-side reflecting member 15 fixed to the support member 14. This not only allows the size of the light-emitting / receiving module 10 to be compact, but also reduces the moment of inertia due to rotation, thereby shortening the measurement interval. The light-receiving-side reflecting member 15 is composed of, for example, a mirror, and reflects the reflected light S2 emitted from the light-collecting unit 12 back toward the light-emitting unit 11, thereby shortening the distance in the YZ plane between the imaging unit 13 or the light-collecting unit 12 and the rotation axis 50 of the light-emitting / receiving module 10. The folding direction may be, for example, a direction toward the center position in the Y direction of the housing 40. The YZ plane is a plane that includes both a line extending in the Y direction and a line extending in the Z direction, and is a plane that is perpendicular to the X direction.

[0032] Specifically, the light-receiving-side reflecting member 15 is positioned at the right end of the support member 14 in a portion deeper than the light-collecting unit 12, and is disposed on the optical path between the imaging unit 13 and the light-collecting unit 12 in the YZ plane, and reflects the light collected by the light-collecting unit 12 toward the imaging unit 13. In addition, the rotation axis 50 of the light-emitting and receiving module 10 is disposed between the light-receiving-side reflecting member 15 and the light-projecting unit 11 in the YZ plane.

[0033] By arranging light-receiving-side reflective member 15 on the optical path between imaging unit 13 and light-collecting unit 12, it is possible to reduce the area of ​​light-receiving-side reflective member 15, since it is only necessary to reflect the light after it has been collected by light-collecting unit 12. Note that light-receiving-side reflective member 15 does not have to be positioned on the optical path between imaging unit 13 and light-collecting unit 12, and light-collecting unit 12 may be arranged on the optical path between light-receiving-side reflective member 15 and imaging unit 13, as in Modification 1 (shown in FIG. 17) described below.

[0034] The light-receiving-side reflecting member 15 protrudes upward from the upper surface of the support member 14. The extending direction of the light-receiving-side reflecting member 15 is the depth direction. The emission direction of the reflected light S2 incident on the light-receiving-side reflecting member 15 can be set by adjusting the installation angle of the light-receiving-side reflecting member 15, and the emission direction of the reflected light S2 is directed toward the light-receiving surface of the image sensor 13a.

[0035] The positional relationship between the image sensor 13a of the imaging unit 13 and the optical axis of the light collecting unit 12 is set to have a Scheimpflug relationship in which the light receiving surface of the image sensor 13a is inclined with respect to the optical axis of the light collecting unit 12. An optical system that satisfies the Scheimpflug relationship can be called a Scheimpflug optical system, and in this embodiment, the light projecting and receiving module 10 is configured by integrally holding the light projecting unit 11, the light collecting unit 12, and the imaging unit 13 on the support member 14 so as to have the Scheimpflug relationship. The Scheimpflug relationship allows the light projected by the light projecting unit 11 to be focused along the light projection axis, thereby enabling the acquisition of a profile image in which the slit light is focused on the light reflected by the workpiece W. This improves the measurement accuracy of the three-dimensional shape data of the workpiece W, thereby enabling the acquisition of a highly accurate profile.

[0036] Even when the light-emitting and receiving module 10 is rotated around the rotation center line A, the relative positional relationship between the light-emitting unit 11, the light-collecting unit 12, the imaging unit 13, and the light-receiving-side reflecting member 15 does not change. Therefore, the Scheimpflug relationship is maintained regardless of the rotation angle of the light-emitting and receiving module 10.

[0037] The imaging unit 13 has a cover glass 13c. The cover glass 13c is formed so as to cover the light receiving surface of the image sensor 13a and is fixed to the image sensor 13a. The cover glass 13c is made of a light-transmitting member that has the property of transmitting reflected light S2 emitted from the light-receiving-side reflecting member 15. The reflected light S2 that has transmitted through the cover glass 13c forms an image on the light receiving surface of the image sensor 13a.

[0038] The rotation axis 50 of the light emitting and receiving module 10 is disposed so as to substantially coincide with the center of gravity of the light emitting and receiving module 10 in the YZ plane. That is, the light emitting and receiving module 10 includes a support member 14, a light projecting unit 11, a light condensing unit 12, an imaging unit 13, and a light-receiving-side reflecting member 15. When the center of gravity of the light emitting and receiving module 10 is measured or calculated with the light projecting unit 11, the light condensing unit 12, the imaging unit 13, and the light-receiving-side reflecting member 15 fixed to the support member 14, the center of gravity substantially coincides with the rotation center line A. In other words, the positions of the rotation axis 50 in the Y and Z directions relative to the support member 14 are set so that the center of gravity of the light emitting and receiving module 10 becomes the center of rotation. The support member 14 is fixed to the rotation axis 50 with a plurality of fastening members (not shown) or the like, so that the support member 14 and the rotation axis 50 do not rotate relative to each other.

[0039] By substantially aligning the center of gravity of the light-emitting / receiving module 10 with the rotational center line A, the moment of inertia due to the rotation of the light-emitting / receiving module 10 is reduced, the load on the motor 20 caused by, for example, vibration is suppressed, and a decrease in the rotational speed of the light-emitting / receiving module 10 is also suppressed. The center of gravity of the light-emitting / receiving module 10 does not need to be exactly aligned with the rotational center line A; for example, a deviation within the allowable manufacturing tolerance is not a problem. Even if the center of gravity of the light-emitting / receiving module 10 is slightly misaligned with the rotational center line A, they can be considered to be substantially aligned. For example, as long as the moment of inertia of the light-emitting / receiving module 10 can be sufficiently reduced, the load on the motor 20 caused by, for example, vibration is sufficiently suppressed, and a decrease in the rotational speed of the light-emitting / receiving module 10 is suppressed, a slight deviation between the center of gravity of the light-emitting / receiving module 10 and the rotational center line A is acceptable, and it can be said that the two are substantially aligned, as long as these effects can be achieved.

[0040] As described above, the increased diameter of the light condenser 12 increases its weight. Therefore, in some cases, the center of gravity of the light emitting / receiving module 10 may be too close to the light condenser 12, making it difficult to design the module so that the center of gravity is closer to the rotation center line A. In such cases, as shown by phantom lines in FIG. 5 only, a weight 16 can be provided on the light emitting / receiving module 10 on the light emitting / receiving module 10's side toward the light condenser 11. This allows the center of gravity of the light emitting / receiving module 10 to be positioned midway between the light emitting / receiving module 11 and the light condenser 12. The weight 16 is disposed on the opposite side of the rotation center line A from the light condenser 12. The weight 16 may be fixed to the support member 14 or to the light emitting module 11. The number of weights 16 is not limited to one, and may be multiple.

[0041] The closer the rotation axis of the light-emitting and receiving module 10 is to the center of gravity, the more stable the rotation and the less load there is on the rotation axis 50, but it is assumed that the light-emitting unit 11 and the light-collecting unit 12 have different weights. With this configuration, the weight is provided in the light-emitting and receiving module 10 at a position closer to the light-emitting unit 11 than to the light-collecting unit 12 so as to reduce the misalignment between the center of gravity of the light-emitting and receiving module 10 and the rotation axis 50 that would result from the difference in weight, thereby stabilizing the rotation and reducing the load on the rotation axis 50.

[0042] The material of the light source housing of the light projector 11 may be made of a material with a higher density than the material of the lens housing of the light collector 12, without providing the weight 16. For example, the support member 14 and the lens housing, which have a large volume, may be made of a relatively low-density material such as aluminum, and the light source housing may be made of a relatively high-density material such as zinc or stainless steel (SUS). This allows the light projector 11 to be made heavier, so that the center of gravity of the light projecting and receiving module 10 can be positioned midway between the light projector 11 and the light collector 12. Alternatively, the material of the housing of the light projector 11 may be made of a material with a higher density than the material of the housing of the light collector 12, and the weight 16 may be provided on the light projector 11 side of the light projecting and receiving module 10.

[0043] 7, the housing 40 is a member for storing the light emitting and receiving module 10, the motor 20, and the motor control unit 30, and has a two-tier structure. That is, the housing 40 has an upper housing component 41 that constitutes the upper part, and a lower housing component 42 that constitutes the lower part. The two-tier structure can also be called a two-layer structure, in which case the upper housing component 41 is the first layer and the lower housing component 42 is the second layer.

[0044] The upper housing component 41 and the lower housing component 42 may be an integral part, or may be formed as separate members. In this embodiment, a case will be described in which the upper housing component 41 and the lower housing component 42 are formed as separate members. In this case, the housing 40 can be formed by joining the upper housing component 41 and the lower housing component 42 using, for example, a fastening member (not shown) or the like.

[0045] As shown in FIG. 7, the upper housing component 41 has an upper peripheral wall portion 43 and an upper wall portion 44. The upper wall portion 44 extends along the YZ plane. The upper peripheral wall portion 43 extends from the peripheral edge of the upper wall portion 44 toward the lower housing component 42. The space formed inside the upper housing component 41 is defined as an upper space R1. The upper space R1 is closed by the lower housing component 42, and the upper space R1 is sealed.

[0046] 2 and 4, a light-projecting window 43a and a light-receiving window 43b are provided in the front portion of the upper peripheral wall portion 43. The light-projecting window 43a and the light-receiving window 43b are made of a light-transmitting material. As shown in FIG. 4, the light-projecting window 43a is disposed so as to face the surface of the light-projecting unit 11 onto which the slit light S1 is irradiated. The size and position of the light-projecting and -receiving window 43a are set so that even if the light-projecting and -receiving module 10 rotates, the slit light S1 can be irradiated from the light-projecting window 43a as long as the rotation angle of the light-projecting and -receiving module 10 is within a predetermined angle range described below.

[0047] Furthermore, the light-receiving window 43b is disposed so as to face the light incident surface of the light-collecting unit 12. The size and position of the light-receiving window 43b are set so that even if the light-emitting and receiving module 10 rotates, the reflected light S2 can enter the light-collecting unit 12 through the light-receiving window 43b as long as the rotation angle of the light-emitting and receiving module 10 is within a predetermined angle range described below.

[0048] As shown in FIG. 7 , the lower housing component 42 has a base plate 45, a lower peripheral wall 46 extending downward from the base plate 45, and a lid member 47. The base plate 45 extends along the YZ plane and closes the lower open portion of the upper housing component 41. The lid member 47 is attached to the lower end of the lower peripheral wall 46. A space formed inside the lower housing component 42 is defined as a lower space R2. The lower space R2 is sealed by the lid member 47. In short, the housing 40 has a structure that seals the interior. A sealed structure is a structure that prevents external dust and debris from entering the housing 40, and can be called, for example, a dustproof structure. The housing 40 does not have to be completely sealed; for example, a gap that allows slight air to pass in and out may be present.

[0049] As shown in Figures 3 and 7, recesses 46a are formed on both the left and right sides of the lower peripheral wall 46 of the lower housing component 42. When viewed along the rotation axis of the light emitting and receiving module 10, the width of the upper space R1 that houses the light emitting and receiving module is configured to be larger than the width of the lower space R2 that houses the motor 20, and the recess 46a is formed on the outer wall of the housing 40 by the step between the upper space R1 and the lower space R2. The recess 46a can be used, for example, as a portion where an operator can insert their fingers to grip the optical displacement meter 1 when installing it. Note that the recess 46a may be provided as needed. This configuration makes it possible to provide a grip that contributes to improving user convenience without creating dead space within the housing 40.

[0050] As shown in FIG. 7, the lower space R2 houses the motor 20 for integrally rotating the light emitting and receiving module 10. The central axis of the motor 20 housed in the lower space R2 coincides with the axis of the rotation shaft 50 and is oriented to extend in the vertical direction. On the other hand, the upper space R1 houses the light emitting and receiving module 10. The upper space R1 and the lower space R2 are aligned in the direction of the rotation axis (the central axis of the motor 20) of the light emitting and receiving module 10, so the light emitting and receiving module 10 housed in the upper space R1 is arranged to be aligned in the direction of the central axis of the motor 20 with respect to the motor 20 housed in the lower space R2. In other words, the optical displacement meter 1 has a multi-stage structure in which the light emitting and receiving module 10 is arranged in the upper stage and the motor 20 is arranged in the lower stage.

[0051] Since the light-emitting and receiving module 10 is arranged to be aligned with the motor 20 in the direction of its central axis, the motor 20 is less likely to have an effect when setting the positional relationship between the light-emitting unit 11 and the light-collecting unit 12 of the light-emitting and receiving module 10. Therefore, it is possible to design the module taking into consideration the fact that the distance between the light-emitting unit 11 and the light-collecting unit 12 cannot be made large, for example, when the installation distance is relatively short.

[0052] The optical displacement meter 1 further includes a bearing 51 for rotatably supporting the rotation shaft 50 of the light emitting and receiving module 10. As described above, the light emitting and receiving module 10 is heavy. Therefore, when the optical displacement meter 1 is used in the position shown in FIG. 1 , for example, the weight of the light emitting and receiving module 10 generates a moment load on the rotation shaft 50. Specifically, due to the difference between the portion of the rotation shaft 50 supported by the bearing 51 and the center of gravity of the light emitting and receiving module 10, a moment load acts on the rotation shaft 50 in a direction that tilts the axis of the rotation shaft 50 with respect to the horizontal plane. Particularly in the case of the two-stage structure described above, the upper housing component 41 and the lower housing component 42 are configured to be aligned in the direction of the central axis of the motor 20 (the rotation shaft of the light emitting and receiving module 10), and therefore the difference between the portion of the rotation shaft 50 supported by the bearing 51 and the center of gravity of the light emitting and receiving module 10 tends to be relatively large. In contrast to this, the bearing 51 of this embodiment is configured to be able to support a moment load that occurs due to a difference between the part of the rotation shaft 50 that is supported by the bearing 51 and the center of gravity of the light emitting and receiving module 10.

[0053] As the bearing 51 capable of supporting the moment load, for example, a cross roller bearing can be used, in which a plurality of rollers 51c are arranged between an annular outer ring member 51a and an inner ring member 51b, and the axes of adjacent rollers 51c are perpendicular to each other in the circumferential direction. That is, a stepped portion 45a into which the outer ring member 51a is fitted is formed in the base plate portion 45 of the lower housing component 42. The outer ring member 51a is fixed to the base plate portion 45 while being fitted into the stepped portion 45a. Meanwhile, a fitting portion 50a into which the inner ring member 51b is fitted is formed in the upper portion of the rotating shaft 50. The inner ring member 51b is fixed while being fitted into the fitting portion 50a. The inner ring member 51b may be fixed to the support member 14 of the light emitting / receiving module 10.

[0054] By using a cross roller bearing as the bearing 51, the rollers 51c come into line contact with the outer ring member 51a and the inner ring member 51b, which significantly improves rigidity compared to ball-type bearings. Therefore, while achieving a thin and compact bearing structure in the axial direction, it can withstand not only the radial load (radial load) of the rotating shaft 50 but also the axial load (thrust load), improving rigidity against the moment load. As a result, smooth rotation can be achieved regardless of the orientation of the optical displacement meter 1 during operation.

[0055] Bearing 51 may be built into motor 20. Furthermore, bearing 51 may be something other than a cross roller bearing. When using something other than a cross roller bearing, for example, two or more ball bearings are arranged at intervals in the axial direction of rotating shaft 50. This results in a bearing structure that can support the moment load. When using two or more ball bearings, one ball bearing can be held in base plate portion 45 of lower housing component 42, and the other ball bearings can be built into motor 20.

[0056] The optical displacement meter 1 further includes an encoder 52 for detecting the rotation angle of the rotary shaft 50, i.e., the rotation angle of the light emitting and receiving module 10. The encoder 52 is an optical encoder. Optical encoders are well known in the art, and although not shown, they have, for example, a rotating plate fixed to the lower end of the rotary shaft 50 and rotating together with the rotary shaft 50, and a fixed plate fixed to the housing 40, and are configured so that light emitted from an emitter is received by a photoreceiver through slits formed at equal intervals in the rotating plate and the fixed plate, and the amount of received light is converted into an electrical signal to generate and output a pulse.

[0057] By using an optical encoder as the encoder 52, the rotation angle detection accuracy is improved compared to a magnetic encoder, but the encoder 52 is susceptible to dust and other factors. To address this issue, the encoder 52 is stored inside the housing 40, specifically in the sealed lower space R2 as described above, to prevent dust and other factors from adhering to the encoder 52. For example, even if dirt or dust enters the housing 40 when adjusting the position and orientation of the imaging unit 13 in the upper space R1 in which the light emitting and receiving module 10 is stored, the space in which the encoder 52 is stored is sealed to prevent the dirt and dust from entering the lower space R2 in which the encoder 52 is stored from the upper space R1 in which the light emitting and receiving module 10 is stored and rotates. This makes it easier to use an optical encoder, which is highly accurate but is easily affected by dirt and dust, enabling high-precision measurements.

[0058] The motor 20 is a direct drive motor that directly drives the light emitting and receiving module 10. Direct drive refers to a drive mode in which no reduction mechanism is interposed between the motor 20 and the driven object. However, as will be described later, the present invention is not limited to direct drive motors.

[0059] The motor 20 includes a stator 21 made up of a coil and a rotor 22 made up of a permanent magnet. The rotor 22 is fixed to the outer periphery of the rotating shaft 50 between a bearing 51 and an encoder 52. The stator 21 is fixed to the lower housing component 42 and is disposed so as to surround the rotor 22.

[0060] The motor control unit 30 is composed of, for example, a microcomputer, ROM, RAM, etc., and operates according to a predetermined program. Specifically, the motor control unit 30 controls the current flowing through the stator 21 to set the rotation speed of the motor 20 to a desired speed and the rotation angle of the motor 20 to a desired angle. An encoder 52 is connected to the motor control unit 30. The motor control unit 30 can calculate the current rotation angle of the light emitting and receiving module 10 based on the pulse signal output from the encoder 52.

[0061] When the scanning start position, scanning end position, scanning range, etc. of the slit light S1 relative to the workpiece W are set by the inspection settings, it is possible to calculate the rotation start position, rotation end position, rotation angle, etc. of the light emitting and receiving module 10 that correspond to the set scanning start position, scanning end position, and scanning range. Based on the results of this calculation, the motor control unit 30 controls the motor 20 to rotate the light emitting and receiving module 10 while maintaining the Scheimpflug relationship inside the housing 40, and scan the slit light S1 in a direction perpendicular to the X direction.

[0062] Because the light emitting and receiving module 10 is stored in the upper space R1 of the housing 40, there is a risk that a portion of the light emitting and receiving module 10 may come into contact with the inner wall of the housing 40 depending on the rotation angle of the light emitting and receiving module 10. In response to this, in this embodiment, the rotation angle range of the light emitting and receiving module 10, which rotates during operation of the optical displacement meter 1, i.e., during measurement, is set to a predetermined angle range that prevents the light emitting and receiving module 10 from coming into contact with the inner wall of the housing 40. In other words, assuming that the light emitting and receiving module 10 has rotated to the first rotation angle, in the YZ plane orthogonal to the X direction, the light emitting and receiving module 10 has a dimension that causes it to come into contact with the inner wall of the housing 40. However, the rotation angle range of the light emitting and receiving module 10, which rotates during measurement, is set to a predetermined angle range that is smaller than the first rotation angle in order to prevent the light emitting and receiving module 10 from coming into contact with the inner wall of the housing 40. With this configuration, the housing 40 can be designed based on the angle range in which the light emitting and receiving module 10 needs to rotate, making it easy to reduce the size of the housing 40.

[0063] Methods for setting the rotation angle range of the light emitting and receiving module 10 to a predetermined angle range include, for example, a mechanical method and a software method. In this embodiment, as a mechanical method, a first stopper 61 and a second stopper 62, which are examples of mechanical components, are provided inside the housing 40 as shown in FIG. 4. In this example, the first stopper 61 and the second stopper 62 are provided so as to protrude upward from the base plate 45. When the light emitting and receiving module 10 rotates around the rotation center line A in the direction of arrow B, the light emitting and receiving module 10 abuts against the first stopper 61 before a portion of the light emitting and receiving module 10 contacts the inner wall of the housing 40, preventing further rotation of the light emitting and receiving module 10 in the direction of arrow B. Furthermore, when the light emitting and receiving module 10 rotates in the direction of arrow C around the rotation center line A, before a part of the light emitting and receiving module 10 comes into contact with the inner wall of the housing 40, the light emitting and receiving module 10 abuts against the second stopper 62, preventing the light emitting and receiving module 10 from rotating further in the direction of arrow C. In other words, the first stopper 61 and second stopper 62 are provided inside the housing 40 to prevent the light emitting and receiving module 10 from rotating outside a predetermined angle range during measurement.

[0064] The first stopper 61 and the second stopper 62 may be made of an elastic material such as rubber or a thermoplastic elastomer. Alternatively, the first stopper 61 and the second stopper 62 may be made of metal, and an elastic material may be provided on the support member 14 at the portion where the first stopper 61 and the second stopper 62 come into contact. This makes it possible to reduce the sound generated when the light emitting and receiving module 10 comes into contact with the first stopper 61 and the second stopper 62.

[0065] Furthermore, it is preferable to abut the support member 14 against the first stopper 61 and the second stopper 62. This is because if the light projecting unit 11, the light collecting unit 12, etc. abut against the first stopper 61 or the second stopper 62, the optical axis may be shifted due to the impact at the time of abutment. Furthermore, the first stopper 61 and the second stopper 62 may be provided on the upper peripheral wall portion 43. Furthermore, only one of the first stopper 61 and the second stopper 62 may be provided.

[0066] Next, a software-based method will be described. That is, the motor control unit 30 can execute contact avoidance control to prevent the light emitting and receiving module 10 from contacting the inner wall of the housing 40. The motor control unit 30 controls the motor 20 to rotate the light emitting and receiving module 10 within a predetermined angle range during measurement, based on the rotation angle obtained by calculating the pulse signal output from the encoder 52. This control is the contact avoidance control. By executing this contact avoidance control, the light emitting and receiving module 10 can be prevented from contacting the inner wall of the housing 40 without providing stoppers 61 and 62. Note that the stoppers 61 and 62 may be provided even when the contact avoidance control is executed.

[0067] Only during measurement is it necessary to prevent the light emitting and receiving module 10 from contacting the inner wall of the housing 40. For example, during non-measurement times such as during maintenance or various settings, it is acceptable for the light emitting and receiving module 10 to contact the inner wall of the housing 40, so the motor control unit 30 can be configured to perform contact avoidance control only during measurement.

[0068] As shown in FIG. 8, the lower housing component 42 is provided with a board storage space R3. In the plan view shown in FIG. 4, the board storage space R3 is offset from the center of the housing 40 toward the rear, and is therefore positioned further rearward than the motor 20 (shown in FIG. 7). The board storage space R3 is located below the upper space R1 in which the light emitting and receiving module 10 is stored, and is therefore a different space from the upper space R1. The board storage space R3 is located at a different position from the upper space R1 with respect to the direction of the rotation axis of the light emitting and receiving module 10, but is located at the same position as the lower space R2 that stores the motor 20. When viewed along the rotation axis of the light emitting and receiving module 10, the upper space R1 and the lower space R2 are located at positions overlapping with the rotation axis, while the board storage space R3 is located at a position not overlapping with the rotation axis. For example, if the size of the light emitting and receiving module 10 is larger than the size of the motor 20, the housing 40 can be made more compact in external shape by using a two-tier structure in which the upper space R1 that stores the light emitting and receiving module 10 is the first tier, and the lower space R2 that stores the motor 20 and the board storage space R3 that stores the control unit 30 are the second tier.

[0069] As shown in FIG. 8 , the board storage space R3 houses a motor control board 31 on which the motor control unit 30 is mounted, a signal processing board 33 on which the signal processing unit 32 is mounted, and a power supply board 35 on which the power supply unit 34 is mounted. The motor control board 31 and the signal processing board 33 are equipped with processors such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and an FPGA (Field Programmable Gate Array) that function as the motor control unit 30 and the signal processing unit 32, as well as storage elements (not shown) such as a RAM (Random Access Memory) and a ROM (Read Only Memory) for storing programs executed by the processors. The boards 31, 33, and 35 are fixed to the lower housing component 42. The motor control unit 30 and the signal processing unit 32 are housed in the board storage space R3, which is separate from the upper space R1. This allows for thermal isolation between the light projecting unit 11, which is particularly prone to heat generation, and the motor control unit 30 and the signal processing unit 32, thereby stabilizing the operation of the motor control unit 30 and the signal processing unit 32. The arrangement of the control unit 3 is not limited to the above example, and may be, for example, a configuration in which the signal processing unit 32 is stored within the housing 40 while the motor control unit 30 is arranged outside the housing 40.

[0070] Because reflected light S2 is incident from the front side of the housing 40, the motor control unit 30, signal processing unit 32, and power supply unit 34, which are stored in the back side of the housing 40, are arranged on the opposite side of the light emitting and receiving module 10 from the side on which reflected light S2 is incident. This prevents the motor control unit 30, signal processing unit 32, and power supply unit 34 from interfering with displacement measurement. Furthermore, when the Z direction is used as a reference, the motor control unit 30, signal processing unit 32, and power supply unit 34 are arranged adjacent to the light emitting and receiving module 10 in the Z direction. Furthermore, because the board storage space R3 is sealed with a lid member 47, dust and the like are prevented from entering the boards 31, 33, and 35.

[0071] The signal processing board 33 is located at the top, the motor control board 31 is located below the signal processing board 33, and the power supply board 35 is located below the motor control board 31. The signal processing board 33 located at the top is closest to the light emitting and receiving module 10, but this signal processing board 33 is located below the support member 14 of the light emitting and receiving module 10. This prevents the light emitting and receiving module 10 from coming into contact with the signal processing board 33 when it rotates within a predetermined angle range. In other words, the motor control unit 30, signal processing unit 32, and power supply unit 34 are all positioned so as to avoid contact with the light emitting and receiving module 10 as it rotates during measurement.

[0072] The power supply unit 34 is a part that supplies power to the light projecting unit 11, the imaging unit 13, the motor control unit 30, the signal processing unit 32, etc. In this embodiment, the power supply unit 34, the motor control unit 30, and the signal processing unit 32 are mounted on different boards, but this is not limiting, and any two or more of them may be integrated and mounted on a single board.

[0073] The signal processing unit 32 is composed of, for example, a microcomputer, ROM, RAM, etc., and operates according to a predetermined program to generate cross-sectional profile data of the workpiece W based on the amount of light received by the imaging unit 13. Wiring indicated by reference numeral 70 in FIG. 4 connects the substrates 31, 33, 35 to the light projecting unit 11 and imaging unit 13. This wiring 70 is flexible and configured so as not to affect the rotational movement of the light projecting and receiving module 10.

[0074] 9, the image sensor 13a of the imaging unit 13 has a plurality of pixels arranged two-dimensionally in a U direction corresponding to the X direction and a V direction perpendicular to the U direction. The signal processing unit 32 acquires the luminance value (amount of received light) of each pixel of the image sensor 13a and calculates an approximation curve of the change in luminance value. The signal processing unit 32 calculates the peak position in the V direction of each pixel row on the calculated approximation curve and acquires the calculated peak position as the displacement of the workpiece W.

[0075] The signal processing unit 32 performs the above-mentioned calculation of the peak position multiple times during the rotation of the light emitting and receiving module 10. The signal processing unit 32 associates the obtained peak position with the rotation angle of the light emitting and receiving module 10 at the time the peak position was obtained, and stores this as measurement data. Because the rotation angle and UV coordinates of the light emitting and receiving module 10 correspond to the XYZ coordinates of the workpiece, cross-sectional profile data of the workpiece W at a desired rotation angle can be generated based on the measurement data. In addition, by acquiring multiple cross-sectional profiles of the workpiece W at different rotation angles, the signal processing unit 32 can generate data on the three-dimensional shape of the workpiece W.

[0076] (Image sensor readout area) As described above, in this embodiment 1, the slit light S1 is scanned across the workpiece W in a direction perpendicular to the X direction by rotating the light projecting and receiving module 10, so the imaging control unit 13b can generate a cross-sectional profile indicating the height of the workpiece W in the Z direction based on the pixel signals read out from the image sensor 13a at each of the different rotation angles of the light projecting and receiving module 10.

[0077] 10 shows an example of measuring the displacement of a workpiece W whose surface W1 is at the same height (the surface W1 is parallel to the Y direction). If the optical displacement meter 1 is moved linearly in a direction parallel to the surface W1 of the workpiece W (indicated by arrow E), since the surface W1 is at the same height, it becomes possible to narrow down the area from which pixel signals of the image sensor 13a are read to a partial area, thereby speeding up processing.

[0078] On the other hand, when the slit light S1 is scanned in a direction perpendicular to the X direction by rotating the light emitting / receiving module 10 as in the first embodiment, it may not be possible to measure the entire surface W1 of the workpiece W in the Y direction, as will be described below. That is, in FIG. 10 , the largest area that can be read by the image sensor 13a is set to a substantially arc-shaped maximum area (measurable range) F1 having a predetermined depth centered on the rotation axis of the imaging unit. If the area from which pixel signals of the image sensor 13a are read during displacement measurement is always set to the maximum area F1, the processing load of the signal processing unit 32 increases, making it difficult to increase the measurement speed. Therefore, it is possible to set the area from which pixel signals of the image sensor 13a are read to the area below the line L1, i.e., the partial area F2.

[0079] However, when the light emitting and receiving module 10 is rotated, the partial area F2 becomes a long arc-shaped area centered on the rotation center line A of the light emitting and receiving module 10. Therefore, even if the surface W1 is at the same height, the part to the right of the straight line L2 is located outside the partial area F2, and measurement cannot be performed in the partial area F2.

[0080] 11, the imaging control unit 13b of the first embodiment is configured to be able to dynamically change a partial area F3 (shown by diagonal lines) from which pixel signals of the image sensor 13a are read out, in accordance with the rotation angle of the light emitting and receiving module 10. The imaging control unit 13b is configured to be able to acquire the rotation angle of the motor 20 based on a signal from the encoder 52, and therefore can change the position of the partial area F3 on the image sensor 13a in the V direction of the image sensor 13a in accordance with the rotation angle of the motor 20.

[0081] An example in which the imaging control unit 13b changes the position of the partial region F3 will be described with reference to Fig. 11. When the rotation angle of the light emitting and receiving module 10 is θ1, the imaging control unit 13b sets the position of the partial region F3 on the image sensor 13a so that the partial region F3 is a lower region of the image sensor 13a. When the rotation angle of the light emitting and receiving module 10 is θ2, the imaging control unit 13b sets the position of the partial region F3 on the image sensor 13a so that the partial region F3 is a middle region in the up-down direction of the image sensor 13a. When the rotation angle of the light emitting and receiving module 10 is θ3, the signal processing unit 32 sets the position of the partial region F3 on the image sensor 13a so that the partial region F3 is an upper region of the image sensor 13a. In other words, when the rotation angle of the light emitting and receiving module 10 changes from θ1 to θ3, the partial area F3 changes from the lower area to the upper area of ​​the image sensor 13a in accordance with the angle change. Conversely, when the rotation angle of the light emitting and receiving module 10 changes from θ3 to θ1, the partial area F3 changes from the upper area to the lower area of ​​the image sensor 13a in accordance with the angle change. Since the rotation angle of the motor 20 and the rotation angle of the light emitting and receiving module 10 correspond to each other, either the rotation angle of the motor 20 or the rotation angle of the light emitting and receiving module 10 may be used in this control. Here, it is assumed that the motor 20 is a direct drive motor (described later), and therefore the rotation angle of the motor 20 and the rotation angle of the light emitting and receiving module 10 are equal. When the motor 20 and the reduction gear mechanism 25 are used, the rotation angle of the motor 20 and the rotation angle of the light emitting and receiving module 10 may differ depending on the rotation ratio.

[0082] The imaging control unit 13b sets the V-direction width H1 of the partial region F3 when the rotation angle of the light emitting and receiving module 10 is θ1, the V-direction width H2 of the partial region F3 when the rotation angle of the light emitting and receiving module 10 is θ2, and the V-direction width H3 of the partial region F3 when the rotation angle of the light emitting and receiving module 10 is θ3 to be the same. In other words, the imaging control unit 13b sets the number of readout pixels in the V-direction of the partial region F3 to be the same at different rotation angles of the light emitting and receiving module 10, and changes the partial region F3 for each rotation angle so that the region from which the amount of received light is read out of the approximately arc-shaped measurable range F1 includes a common height in the Z-direction. If the surface of the workpiece W is flat, the imaging control unit 13b can also change the partial region F3 for each rotation angle so that the region from which the amount of received light is read out of the approximately arc-shaped measurable range F1 approximately coincides in the Z-direction from one end to the other of the approximately arc-shaped measurable range F1. This allows the imaging control unit 13b to move the partial region F3, from which pixel signals are read out from the image sensor 13a, in the V direction so that at least a portion of the measurement range in the Z direction is common regardless of the rotation angle of the light projecting and receiving module 10. Note that the width H1 in the V direction of the partial region F3 when the rotation angle of the light projecting and receiving module 10 is θ1 may be different from the width H2 in the V direction of the partial region F3 when the rotation angle of the light projecting and receiving module 10 is θ2. Similarly, the width H1 in the V direction of the partial region F3 when the rotation angle of the light projecting and receiving module 10 is θ1 may be different from the width H3 in the V direction of the partial region F3 when the rotation angle of the light projecting and receiving module 10 is θ3.

[0083] The imaging control unit 13b is configured to be able to set a partial area F3 from which pixel signals of the image sensor 13a are read out, based on the rotation angle of the light-emitting and receiving module 10 and the height of the workpiece W corresponding to the rotation angle of the light-emitting and receiving module 10. For example, Fig. 12 shows a case where the height of the surface W1 of the workpiece W varies depending on the part, and the height of the surface W1 is lower when the rotation angle of the light-emitting and receiving module 10 is θ2 compared to when the rotation angle of the light-emitting and receiving module 10 is θ1. Also, the height of the surface W1 is higher when the rotation angle of the light-emitting and receiving module 10 is θ3 compared to when the rotation angle of the light-emitting and receiving module 10 is θ2.

[0084] 12, when the rotation angle of the light-emitting and receiving module 10 is θ1, the imaging control unit 13b sets the position of the partial region F3 on the image sensor 13a so that the partial region F3 is a lower region of the image sensor 13a. When the rotation angle of the light-emitting and receiving module 10 is θ2, the imaging control unit 13b also sets the position of the partial region F3 on the image sensor 13a so that the partial region F3 is a lower region of the image sensor 13a. On the other hand, when the rotation angle of the light-emitting and receiving module 10 is θ3, the imaging control unit 13b sets the position of the partial region F3 on the image sensor 13a so that the partial region F3 is an upper region of the image sensor 13a.

[0085] When setting the position of the partial area F3 based on the rotation angle of the light-emitting / receiving module 10 and the height of the workpiece W corresponding to the rotation angle of the light-emitting / receiving module 10, the imaging control unit 13b determines a correspondence between each rotation angle of the light-emitting / receiving module 10 and the height of the workpiece W corresponding to each rotation angle based on information obtained by measuring the workpiece W over an area wider than the partial area F3 of the image sensor 13a before operation begins. After operation begins, the imaging control unit 13b can determine the partial area F3 so that, for each rotation angle, the position of the image sensor 13a in the V direction corresponding to the height of the workpiece W is included based on this correspondence. That is, when setting the optical displacement meter 1, the displacement of the workpiece W is measured over an area wider than the partial area F3 of the image sensor 13a. At this time, the displacement of the workpiece W may be measured over the maximum area F1 of the image sensor 13a. This allows the displacement of the workpiece W as shown in FIG. 12 to be measured over the entire Y direction. This measurement information is temporarily stored.

[0086] After measuring the displacement of the workpiece W in an area wider than the partial area F3 of the image sensor 13a, the imaging control unit 13b sets the position of the partial area F3 on the image sensor 13a so that the partial area F3 is a lower area of ​​the image sensor 13a when the rotation angle of the light-emitting and receiving module 10 is θ1 and θ2, based on the measurement information, and sets the position of the partial area F3 on the image sensor 13a so that the partial area F3 is an upper area of ​​the image sensor 13a when the rotation angle of the light-emitting and receiving module 10 is θ3. In other words, the imaging control unit 13b speeds up processing by setting the partial area F3 to an area narrower than the maximum area F1 of the image sensor 13a, and sets the position of the partial area F3 on the image sensor 13a so that the surface W1 of the workpiece W can be measured regardless of the rotation angle of the light-emitting and receiving module 10. During operation, the position of the partial area F3 on the image sensor 13a dynamically changes depending on the rotation angle of the light-emitting and receiving module 10, so that the displacement of the workpiece W can be measured over the entire Y direction.

[0087] When determining the correspondence relationship between the rotation angle of the light emitting and receiving module 10 and the height of the workpiece W, the imaging control unit 13b can also determine the correspondence relationship based on actual size data or design data of the workpiece W. For example, in the case of a workpiece W as shown in FIG. 12, a measurement operator or the like can measure the height of the workpiece W for each portion using a measuring device (not shown), thereby obtaining actual size data of the workpiece W. The obtained actual size data of the workpiece W is input to the imaging control unit 13b. In this case, based on the actual size data of the workpiece W, the imaging control unit 13b determines, for example, that when the rotation angle of the light emitting and receiving module 10 is θ1 and θ2, the partial region F3 is the lower region of the image sensor 13a, and when the rotation angle of the light emitting and receiving module 10 is θ3, the partial region F3 is the upper region of the image sensor 13a.

[0088] Furthermore, design data (e.g., CAD data) of the workpiece W can be input to the imaging control unit 13b. The height of the surface W1 of the workpiece W can be acquired for each portion using the design data of the workpiece W. This allows the position of the partial area F3 on the image sensor 13a to be determined in the same way as when actual size data of the workpiece W is input.

[0089] (Modification 1 of Embodiment 1) FIG. 13 shows a light-emitting / receiving module 10 according to a first modification of the first embodiment. The light-emitting / receiving module 10 of the first modification differs from those of the above embodiment in the positions of the light-emitting unit 11, the light-collecting unit 12, the imaging unit 13, and the light-receiving-side reflecting member 15. Specifically, the rotation axis 50 of the light-emitting / receiving module 10 is disposed at a position overlapping the light-collecting unit 12 in the YZ plane. That is, as described above, it is desirable to reduce the moment of inertia due to the rotation of the light-emitting / receiving module 10 as much as possible. However, providing a weight 16 as shown by the imaginary line in FIG. 5 may undesirably increase the weight of the light-emitting / receiving module 10. Therefore, a method for reducing the moment of inertia due to the rotation of the light-emitting / receiving module 10 without providing the weight 16 can be adopted in which the heavier light-collecting unit 12 and the rotation axis 50 of the light-emitting / receiving module 10 overlap in the YZ plane. As a result, at least a portion of the light-collecting unit 12 is disposed on an extension of the rotation axis 50 of the light-emitting / receiving module 10. It is not necessary for the rotation axis 50 to completely overlap with the light collecting unit 12, but it is sufficient that at least a part of the rotation axis 50 and at least a part of the light collecting unit 12 overlap with each other when viewed from the direction of the rotation center line A. This makes it possible to eliminate the need for the weight 16 or to make the weight 16 lighter.

[0090] In addition, in Modification 1, imaging unit 13 and light-receiving-side reflecting member 15 are arranged to sandwich light-collecting unit 12. As a result, light-collecting unit 12 in Modification 1 is arranged on the optical path between light-receiving-side reflecting member 15 and imaging unit 13 in the YZ plane, and collects light reflected by light-receiving-side reflecting member 15 and makes it incident on imaging unit 13.

[0091] Furthermore, the light-emitting and receiving module 10 of Modification 1 includes a light-emitting-side reflecting member 17. That is, the light-emitting unit 11 of Modification 1 is positioned so that the slit light S1 emitted from the optical system 11b is directed toward the left rear side. This allows the light-emitting unit 11 to be closer to the rotation center line A, further reducing the moment of inertia caused by the rotation of the light-emitting and receiving module 10; however, the workpiece W is located on the opposite side from the slit light S1 emitted from the optical system 11b. Correspondingly, the light-emitting-side reflecting member 17 is positioned so as to reflect the slit light S1 emitted from the optical system 11b of the light-emitting unit 11 toward the workpiece W. The light-emitting-side reflecting member 17 is fixed to the support member 14 or the light-emitting unit 11, and its relative positional relationship with the light-emitting unit 11 does not change even when the light-emitting and receiving module 10 rotates.

[0092] (Modification 2 of Embodiment 1) 14 and 15 show an optical displacement meter 1 according to a second modification of the first embodiment. Fig. 14 is a diagram showing the internal structure of the optical displacement meter 1 as seen from above, and Fig. 15 is a diagram showing the internal structure of the optical displacement meter 1 as seen from below.

[0093] In the optical displacement meter 1 of the second modification, the motor 20 is not a direct drive motor, but is configured to rotate the light emitting and receiving module 10 via a speed reduction mechanism 25. As shown in FIG. 14, the motor 20 is stored in the upper space R1 together with the light emitting and receiving module 10. As shown in FIG. 15, the output shaft 20a of the motor 20 passes downward through the substrate 45 and reaches the lower space R2. In addition, the driven shaft 10a fixed to the light emitting and receiving module 10 also passes downward through the substrate 45 and reaches the lower space R2.

[0094] The reduction gear mechanism 25 is housed in the lower space R2 and includes a drive pulley 25a fixed to the output shaft 20a of the motor 20, a driven pulley 25b fixed to the driven shaft 10a, and a transmission belt 25c wound around the drive pulley 25a and the driven pulley 25b. The drive pulley 25a has a smaller diameter than the driven pulley 25b. The transmission belt 25c is a timing belt.

[0095] In Modification 2, when the output shaft 20a of the motor 20 housed in the upper space R1 rotates, the drive pulley 25a rotates, and the rotational force of the drive pulley 25a is transmitted to the driven pulley 25b via the transmission belt 25c. The drive force transmitted to the driven pulley 25b is then transmitted to the driven shaft 10a, so that the motor 20 can rotate the light-emitting and receiving module 10. In Modification 2, the driven shaft 10a serves as the rotation axis of the light-emitting and receiving module 10.

[0096] The speed reduction mechanism 25 is not limited to a combination of the pulleys 25a, 25c and the transmission belt 25c, but may be, for example, a combination of a drive sprocket, a driven sprocket and a timing chain, or a combination of multiple gears. The type of the motor 20 that can be used may be, for example, a DC motor, a stepping motor, a servo motor, or the like.

[0097] (Embodiment 2) 16 to 18 show an optical displacement meter 1 according to a second embodiment of the present invention. In this second embodiment, the structure of the housing 400, the positional relationship between the motor 20 and the light emitting and receiving module 100, etc. are different from those in the first embodiment. In the following, the same parts as those in the first embodiment are given the same reference numerals and their explanations are omitted, and the different parts will be explained in detail.

[0098] 16 and 18, the housing 400 has a single-stage structure, and the boards 31, 33, and 35 are also stored inside the housing 400. By partitioning the inside of the housing 400, the space storing the boards 31, 33, and 35 can be made different from the space storing the light emitting and receiving module 100.

[0099] The housing 400 includes a bottom wall 401, a peripheral wall 402 extending upward from the peripheral edge of the bottom wall 401, and a lower lid member 403 for closing the upper open portion. A light projection window 402a through which the slit light S1 emitted from the light projection unit 11 passes, and a light receiving window 402b through which the reflected light S2 reflected from the workpiece W passes are provided in the front portion of the peripheral wall 402.

[0100] 18, an annular wall portion 404 is formed in the center of the lower wall portion 401, protruding into the housing 400 and extending around the rotation center line A. An end wall portion 405 is formed at the tip of the annular wall portion 404, extending in the radial direction of the rotation center line A. An opening 405a is formed in the center of the end wall portion 405, into which the rotating shaft 50 is inserted.

[0101] A motor storage space R4 is formed inside the annular wall portion 404. The stator 21 and rotor 22 of the motor 20 are stored in the motor storage space R4. The stator 21 of the motor 20 is fixed to the inner surface of the annular wall portion 404. That is, in this embodiment, the annular wall portion 404 and the end wall portion 405 form a stator holding portion. On the other hand, the rotor 22 of the motor 20 is fixed to the rotating shaft 50.

[0102] The outer ring member 51a of the bearing 51 is fixed to the end wall portion 405 while being fitted into a step portion 405b formed in the end wall portion 405. As a result, the bearing 51 is held in a stator holding portion formed by the annular wall portion 404 and the end wall portion 405. Meanwhile, the inner ring member 51b is fitted into a fitting portion 50a formed on the rotating shaft 50.

[0103] The motor storage space R4 also stores the encoder 52. A lower cover member 406 is provided at the lower end of the housing 400. The lower cover member 406 seals the motor storage space R4, preventing dust and the like from adhering to the encoder 52.

[0104] The light-emitting and receiving module 100 includes a light-emitting unit 11, a light-collecting unit 12, an imaging unit 13, a weight 16, etc., as in the first embodiment, but the support member 110 that integrally holds the light-emitting unit 11, the light-collecting unit 12, and the imaging unit 13 is significantly different from the support member 14 in the first embodiment.

[0105] That is, in the first embodiment, the light-emitting and receiving module 10 and the motor 20 (bearing 51 and encoder 52) are aligned in the direction of the rotation axis 50 (height direction), whereas in the second embodiment, at least one of the motor 20, the bearing 51 supporting the rotation axis 50, or the encoder 52 connected to the motor 20 is included within a portion of the height range in the direction of the rotation axis 50 of the light-emitting and receiving module 100. This makes it possible to design the light-emitting and receiving module 100 so that, when setting the positional relationship between the light-emitting unit 11 and the light-collecting unit 12, it is possible to take into consideration a large gap between the light-emitting unit 11 and the light-collecting unit 12, for example, when the installation distance is relatively long.

[0106] Specifically, the support member 110 includes a fixed portion 111 fixed to the rotation shaft 50, one-side vertical plate portion 112, the other-side vertical plate portion 113, a light condensing portion holding portion 114, and a light projecting portion holding portion 115. The fixed portion 111, the one-side vertical plate portion 112, the other-side vertical plate portion 113, the light condensing portion holding portion 114, and the light projecting portion holding portion 115 may be integrally molded or may be formed by combining separate members.

[0107] The fixed portion 111 has a plate shape extending in the radial direction of the rotation shaft 50. In this embodiment, it has a circular shape as shown in FIG. 17 and is arranged to cover the end wall portion 405 from above as shown in FIG. 18. The one-side vertical plate portion 112 extends downward along the direction of the rotation shaft 50 from the right side of FIG. 18, i.e., from one radial side of the rotation shaft 50 at the fixed portion 111. The other-side vertical plate portion 113 extends downward along the direction of the rotation shaft 50 from the left side of FIG. 18, i.e., from the other radial side of the rotation shaft 50 at the fixed portion 111. The one-side vertical plate portion 112 and the other-side vertical plate portion 113 are arranged to face the annular wall portion 404. The one-side vertical plate portion 112 and the other-side vertical plate portion 113 are curved in an arc like the annular wall portion 404, and rotate while maintaining a certain gap between them and the annular wall portion 404 when the light emitting and receiving module 100 rotates.

[0108] The one-side vertical plate portion 112 and the other-side vertical plate portion 113 may be integrally formed. For example, an annular peripheral wall portion (not shown) may be formed extending downward from the peripheral edge of the fixing portion 111, and the one-side vertical plate portion 112 and the other-side vertical plate portion 113 may be formed at portions of the peripheral direction of this peripheral wall portion.

[0109] The light collecting unit holding unit 114 is in the form of a plate extending radially from the lower end of the one-side vertical plate unit 112 about the rotation axis 50. The light collecting unit 12, the imaging unit 13, the cover glass 13c, etc. are held on the upper surface of the light collecting unit holding unit 114. Therefore, the rotation axis 50 of the light emitting and receiving module 100 is disposed at a position that does not overlap with the light collecting unit 12 and the imaging unit 13 in the YZ plane.

[0110] The light-projecting unit holder 115 has a plate shape extending radially from the lower end of the other-side vertical plate portion 113 about the rotation axis 50. The light-projecting unit 11, weight 16, etc. are held on the upper surface of the light-projecting unit holder 115. Therefore, the rotation axis 50 of the light-projecting and light-receiving module 100 is disposed at a position that does not overlap with the light-projecting unit 11 in the YZ plane.

[0111] In this way, the light-collecting unit holding part 114 and the light-projecting unit holding part 115 are arranged to sandwich the rotation shaft 50, and protrude in opposite directions radially of the rotation shaft 50. The weight 16 can be fixed to the light-projecting unit holding part 115. Furthermore, the weight 16 may be fixed to the side of the fixing part 111 opposite to the side on which the one-side vertical plate part 112 is formed.

[0112] Support member 110, which has fixing portion 111, one-side vertical plate portion 112, other-side vertical plate portion 113, light collecting portion holding portion 114, and light emitting portion holding portion 115, has a plurality of bent portions 110A in a cross section in the X direction. Because support member 110 has a structure with a plurality of bent portions 110A in this way, the rigidity of support member 110 can be increased compared to when it is a flat plate.

[0113] The motor 20 and bearing 51 are disposed between one side vertical plate portion 112 and the other side vertical plate portion 113 of the support member 110. The bearing 51 is disposed between the one side vertical plate portion 112 and the other side vertical plate portion 113 at a location closer to the fixed portion 111 than the motor 20. As a result, the motor 20 and bearing 51 are included within a portion of the height range of the light emitting and receiving module 100. Although not shown, only the motor 20 may be included within the height range of the light emitting and receiving module 100, or only the bearing 51 may be included within the height range of the light emitting and receiving module 100.

[0114] A rotation drive unit is configured by at least the motor 20, the bearing 51, and the encoder 52. The motor 20 is fixed to a wall surface (the lower wall portion 401 and the annular wall portion 404) adjacent to the light projecting and receiving surface, which is provided with a light projecting window 402a that passes the slit light and a light receiving window 402b that passes the reflected light (collectively referred to as the light projecting and receiving windows).

[0115] In this embodiment, the light-emitting and light-receiving window is composed of a light-emitting window 402a and a separate light-receiving window 402b, but the light-emitting and light-receiving windows may be integrally formed. The light-emitting and light-receiving surface is the surface that forms the exterior of the housing 400 on which the light-emitting and light-receiving windows are provided, and is a surface made up of multiple flat surfaces formed by the windows, as shown in Figures 4 and 14. When the light-emitting and light-receiving windows are integrally formed, the light-emitting and light-receiving surface may be a surface made up of a single flat surface formed by the light-emitting and light-receiving windows.

[0116] The support member 110 supports the light emitting and receiving module 100 so that the light emitting and receiving module 100 is positioned in a plane perpendicular to the X direction and in which the rotation drive unit is located. The support member 110 has a first portion (e.g., fixed portion 111) and a second portion (e.g., light collecting unit holding portion 114 and light emitting unit holding portion 115) that are formed by multiple bent portions 110A and have different heights in the rotation axis direction, and the rotation drive unit and the light emitting and receiving module 100 are located between the plane formed by the first portion and the plane formed by the second portion in at least a cross section including the rotation axis. This configuration increases the rigidity of the support member 110 and enables the thickness of the housing 400 in the X direction to be reduced.

[0117] Although not shown, the encoder 52 may be included within the height range of the light emitting and receiving module 100. For example, by disposing the encoder 52 in the middle or upper end of the rotation shaft 50, the encoder 52 will be included within the height range of the light emitting and receiving module 100. Only the encoder 52 may be included within the height range of the light emitting and receiving module 100, only the motor 20 and the encoder 52 may be included within the height range of the light emitting and receiving module 100, or only the bearing 51 and the encoder 52 may be included within the height range of the light emitting and receiving module 100.

[0118] Light-receiving-side reflecting member 15 is disposed on the optical path between light-collecting unit 12 and light-receiving window 402b of housing 400 in the YZ plane, and reflects reflected light S2 that has passed through light-receiving window 402b toward light-collecting unit 12. That is, light-collecting unit 12 is disposed on the optical path between light-receiving-side reflecting member 15 and imaging unit 13 in the YZ plane, and collects reflected light S2 reflected by light-receiving-side reflecting member 15 and causes it to enter imaging unit 13. This allows reflected light S2 to be reflected back toward light-projecting unit 11 so that the distance between imaging unit 13 or light-collecting unit 12 and rotation axis 50 of light-projecting and receiving module 100 in the YZ plane is shortened.

[0119] (Modification of the second embodiment) 19 shows an optical displacement meter 1 according to a modified example of embodiment 2. In this modified example, the light-receiving-side reflecting member 15 is omitted. By arranging the light-collecting unit 12 so that the optical axis of the light-collecting unit 12 faces the light-receiving window 402b of the housing 400, the reflecting member 15 becomes unnecessary.

[0120] This modified example is also an example of a layout in which a wide interval is ensured between light projecting unit 11 and light collecting unit 12. For example, this modified example can be applied when the installation distance is relatively long.

[0121] The above-described embodiments are merely illustrative in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of equivalents of the claims are within the scope of the present invention. For example, a light-emitting-side reflective member may be provided in the second embodiment. Furthermore, a speed reduction mechanism may be provided in the second embodiment. Furthermore, in the first and second embodiments, the motor 20 may be provided outside the housing 40, 400. Furthermore, the configuration in which the partial area F3 (shown in FIGS. 11 and 12) from which pixel signals of the image sensor 13a are read out is changed in accordance with the rotation angle of the light-emitting and receiving module 10 can also be applied to the second embodiment. [Industrial Applicability]

[0122] As described above, the optical displacement meter according to the present disclosure can be used, for example, to obtain data on the three-dimensional shape of a workpiece. [Explanation of symbols]

[0123] 1 Optical displacement gauge 10, 100 Light emitting and receiving module 11 Light projector 12 Receiving lens 13 Imaging unit 20 Motor 30 Motor control unit (calculation unit) 32 Signal Processing Section double work

Claims

1. An optical displacement meter of a light-cutting type that measures a cross-sectional profile of a workpiece having a height in the Z direction based on the principle of triangulation and measures the three-dimensional shape of the workpiece without moving relative to the workpiece, a light projecting unit that projects slit light extending in the X direction onto the workpiece; a light receiving lens that collects light reflected by the workpiece; an image sensor that receives the reflected light collected by the light receiving lens; a support member to which the light projecting unit, the light receiving lens, and the image sensor are fixed, and which integrally holds the light projecting unit, the light receiving lens, and the image sensor so that a Scheimpflug relationship is satisfied; a motor that rotates the support member while maintaining the Scheimpflug relationship; a control unit that controls the motor to cause the slit light to scan in a direction perpendicular to the X direction; an imaging control unit that controls the image sensor; a signal processing unit that generates the cross-sectional profile at each rotation angle of the motor based on the amount of light received by the image sensor, The plane formed by the slit light irradiated onto the workpiece is on the same plane as the focal plane formed by the light receiving lens and the image sensor regardless of the rotation angle, and is separated from the rotation axis when viewed from the direction of the rotation axis of the support member, the imaging control unit changes the partial area from which the amount of light received by the image sensor is read out to the partial area corresponding to each rotation angle, based on the partial area predetermined for each rotation angle, so as to correspond to a measurement range that differs depending on the rotation angle but is in focus due to the Scheimpflug relationship, to the partial area corresponding to each rotation angle.

2. 2. The optical displacement meter according to claim 1, By the rotation of the support member, a substantially arc-shaped measurable range having a predetermined depth is formed around the center of the rotation axis of the support member, The imaging control unit changes the partial area for each rotation angle so that a common Z-direction height is included in the area from which the amount of received light is read out within the measurable range.

3. 3. The optical displacement meter according to claim 2, the imaging control unit changes the partial area for each rotation angle so that the area of ​​the measurable range from which the amount of received light is read out substantially coincides with the Z direction from one end to the other end of the substantially arc-shaped optical displacement meter.

4. 2. The optical displacement meter according to claim 1, The imaging control unit is an optical displacement meter that commonizes the number of readout pixels in the V direction of the image sensor in the partial region at each of the rotation angles.

5. 2. The optical displacement meter according to claim 1, The imaging control unit determines the partial area based on each rotation angle and the height of the workpiece corresponding to each rotation angle so that the partial area includes the V-direction position of the image sensor corresponding to the height of the workpiece for each rotation angle.

6. 6. The optical displacement meter according to claim 1, The imaging control unit determining a correspondence relationship between each rotation angle and a height of the workpiece based on information obtained by measuring the workpiece in an area including the partial area of ​​the image sensor and wider than the partial area before the start of operation; An optical displacement meter that determines the partial area based on the correspondence relationship after the start of operation so that the partial area includes a V-direction position of the image sensor corresponding to the height of the workpiece for each rotation angle.

7. 6. The optical displacement meter according to claim 1, The imaging control unit Before starting operation, a correspondence relationship between each rotation angle and the height of the workpiece is determined based on actual size data or design data of the workpiece; An optical displacement meter that determines the partial area based on the correspondence relationship after the start of operation so that the partial area includes a V-direction position of the image sensor corresponding to the height of the workpiece for each rotation angle.

8. 6. The optical displacement meter according to claim 1, The partial area from which the amount of light received by the image sensor for each rotation angle is read out is determined in advance before scanning by the slit light is started.

9. 6. The optical displacement meter according to claim 1, the control unit causes the motor to cause the support member to perform a swinging motion around a rotation axis, thereby scanning the slit light; The partial area from which the amount of light received by the image sensor for each rotation angle is read out is determined in advance before scanning of the slit light in one direction of the swinging motion is started.

Images