Probe and shape measurement device

Abstract

The probe (26) is provided with: a light incidence / emission unit (cable tip surface (33a)) that emits measurement light (LA) and receives reflected light (LB); and a light splitting element (beam splitter (44)) that has a first surface (44a), a second surface (44b), and a third surface (44c), and that performs light splitting on the measurement light (LA) that has entered the first surface (44a) from the light incidence / emission section, and emits a portion thereof from the second surface (44b), performs light splitting on the reflected light (LB) that has entered the second surface (44b), and emits a portion thereof from the first surface (44a) toward the light incidence / emission section. The remaining part is emitted from the third surface (44c); a light receiving element (45) that receives reflected light (LB) emitted from the third surface (44c); and a tip attachment part (attachment shaft (46)) to which a first probe tip (50) for non-contact measurement and a second probe tip (60) for contact measurement can be selectively attached.

Description

TECHNICAL FIELD

[0001] The present application relates to a probe for detecting a position coordinate of a measurement point and a shape measuring apparatus provided with the probe. BACKGROUND

[0002] As a shape measuring apparatus that measures a shape of a measurement object, for example, a three-dimensional coordinate measuring machine that uses a probe to detect a position coordinate (three-dimensional coordinate) of each measurement point of a measurement object (workpiece) to thereby obtain a shape of the measurement object is known.

[0003] For example, the three-dimensional coordinate measuring machine described in Patent Literature 1 measures a shape of a measurement object by performing, for each measurement point of the measurement object, contact of a probe's probe ball for contact measurement of the measurement point, and acquisition of a position coordinate of the probe ball at the time of contact of the probe ball with the measurement point.

[0004] Further, the three-dimensional coordinate measuring machine described in Patent Literature 2 measures a shape of a measurement object by, for each measurement point of the measurement object, performing emission of a measurement light toward the measurement point by an optical probe for non-contact measurement, and reception of a reflected light at the measurement point, and distance calculation from the optical probe to the measurement point based on a known measurement method using an interferometer.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2015-075431

[0008] Patent Literature 2: Japanese Patent Application Publication No. 2020-098180 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] Figure 15 is a diagram for explaining a problem of a conventional probe for contact measurement. As shown in Figure 15 the probe 200 for contact measurement is provided with a stylus 201, a probe ball 202 provided at a distal end portion of the stylus 201, a fulcrum portion 203 provided at a base end portion of the stylus 201, and a sensor 204. The sensor 204 is a strain gauge or the like that detects contact of the probe ball 202 with each measurement point of a workpiece W as a measurement object.

[0011] In such a probe 200, there is a distance between the probe ball 202 (a point of application) and the fulcrum portion 203 and the sensor 204 (a point of action). Therefore, as with the three-dimensional coordinate measuring machine described in Patent Document 1, in a case where the probe ball 202 is brought into contact with each measurement point of the workpiece W to detect the position coordinates of each measurement point, an error caused by the deflection of the stylus 201 can occur. Further, in a case where the three-dimensional coordinates of a fine edge shape and a free-form surface are detected, a radius correction error of the probe ball 202 can occur. Furthermore, the fulcrum portion 203 needs to be specially designed, and the cost becomes high.

[0012] On the other hand, as with the three-dimensional coordinate measuring machine described in Patent Document 2, in a case where an optical probe for non-contact measurement is used, the problem as in the case where the probe 200 for contact measurement is used does not occur. However, in a case where the optical probe is used, the sensitivity of the optical probe becomes unstable with respect to a measurement target having a small roughness (for example, a mirror surface), and thus it is difficult to perform shape measurement of the measurement target. This problem becomes significant particularly in a case where a free-form surface is measured.

[0013] The present application was completed in view of such a situation, and an object thereof is to provide a probe and a shape measuring device capable of performing shape measurement of a measurement target with high accuracy regardless of the kind of the measurement target.

[0014] - Means for Solving the Problem -

[0015] The probe for achieving the object of the present application is provided with: a light incident / emergent section which emits measurement light and which receives reflected light of the measurement light; a light splitting element which has a first surface, a second surface, and a third surface, splits the measurement light incident on the first surface from the light incident / emergent section, and emits a part of the measurement light from the second surface, splits the reflected light of the measurement light incident on the second surface from the second surface, and emits a part of the reflected light from the first surface toward the light incident / emergent section, and emits the remaining part of the reflected light from the third surface; a light receiving element which receives the reflected light emitted from the third surface; and a tip section mounting section which has an optical path of the measurement light emitted from the second surface and the reflected light incident on the second surface, and which is capable of selectively mounting a first probe tip section for non-contact measurement and a second probe tip section for contact measurement, the first probe tip section being provided with: a hollow first shaft which has a first tip section and a first base section, and which forms the optical path in the case where the first base section is detachably mounted to the tip section mounting section; and an optical element which is provided to the first tip section, emits the measurement light incident on the second surface through the inside of the first shaft toward a measurement target, and emits the reflected light from the measurement target toward the second surface, the second probe tip section being provided with: a hollow second shaft which has a second tip section and a second base section, and which forms the optical path in the case where the second base section is detachably mounted to the tip section mounting section; a tip ball which is provided to the second tip section, and which comes into contact with the measurement target; and a retroreflective element which retroreflects the measurement light incident on the second surface through the inside of the second shaft, and causes the reflected light to be incident on the second surface.

[0016] According to the probe, it is possible to selectively mount the first probe tip section for non-contact measurement and the second probe tip section for contact measurement in the tip section mounting section depending on the measurement target.

[0017] In the probe according to the other aspect of the present application, the optical element is a reflective element which reflects the measurement light incident on the second surface through the inside of the first shaft toward the measurement target, and reflects the reflected light from the measurement target toward the second surface.

[0018] In the probe according to the other aspect of the present application, the retroreflective element is provided inside the second tip section.

[0019] In the probe according to the other aspect of the present application, the tip ball is a retroreflective ball lens which functions as the retroreflective element. Thus, it is possible to reduce the number of components of the second probe tip section, and to achieve cost reduction.

[0020] In the probe according to the other aspect of the present application, the refractive index of the retroreflective ball lens is 2. Thus, it is possible to make the back focal length of the retroreflective ball lens 0.

[0021] In the probe according to another aspect of the present application, the light-receiving element is a position detection sensor or a two-dimensional image sensor. Thus, the incident position coordinates of the reflected light on the light-receiving surface of the light-receiving element can be detected.

[0022] In the probe according to another aspect of the present application, a collimator lens is provided between the light-incident / emitted portion and the first surface.

[0023] In the probe according to another aspect of the present application, a rotation mechanism is provided that rotates the front end portion mounting portion and the first probe front end portion in the rotation axis direction centered on the optical axis of the optical path when the first probe front end portion is mounted to the front end portion mounting portion. Thus, the measurement light can be rotationally scanned with respect to the measurement surface of the measurement target object.

[0024] A shape measurement apparatus for achieving the object of the present application measures the shape of a measurement target object, and includes the probe described above, a displacement mechanism that can displace the probe, a light source of measurement light that is optically connected to the light-incident / emitted portion, and an interference signal detection portion that is optically connected to the light-incident / emitted portion and detects an interference signal between the reflected light incident to the light-incident / emitted portion and reference light that is a portion of the measurement light reflected on a different reflection surface from the measurement target object and the retroreflective element.

[0025] In the shape measurement apparatus according to another aspect of the present application, when the second probe front end portion is mounted to the front end portion mounting portion, an incident position coordinate acquisition portion that continuously acquires the incident position coordinates of the reflected light on the light-receiving surface of the light-receiving element, a distance calculation portion that continuously calculates the distance from the predetermined reference position to the retroreflective element based on the interference signal detected by the interference signal detection portion, and a contact detection portion that detects the contact of the front end ball with the measurement target object based on the incident position coordinates continuously acquired by the incident position coordinate acquisition portion and the distance continuously calculated by the distance calculation portion in the driving of the displacement mechanism are provided. Thus, the contact of the front end ball with the measurement target object can be detected simply.

[0026] In the shape measurement apparatus according to another aspect of the present application, the displacement mechanism includes an XYZ coordinate acquisition portion that can displace the probe at least in the XYZ directions of a mechanical coordinate system of the shape measurement apparatus and acquire the XYZ coordinates of the probe in the mechanical coordinate system, and a front end ball coordinate calculation portion that calculates the XYZ coordinates of the front end ball in the mechanical coordinate system based on the XYZ coordinates of the probe acquired by the XYZ coordinate acquisition portion, the incident position coordinates acquired by the incident position coordinate acquisition portion, and the distance calculated by the distance calculation portion when the contact detection portion detects the contact of the front end ball with the measurement target object. Thus, the XYZ coordinates of the front end ball in the mechanical coordinate system can be obtained.

[0027] In the shape measuring apparatus according to the other aspect of the present application, the tip sphere coordinate calculation section acquires in advance information indicating a relationship between XYZ directions of the machine coordinate system and two-dimensional directions of the light receiving surface and an exit direction of the measuring light from the second surface, and calculates XYZ coordinates of the tip sphere on the basis of the XYZ coordinates of the probe, the incident position coordinates, the distance, and the information. Thus, the XYZ coordinates of the tip sphere in the machine coordinate system are obtained.

[0028] -Effects of Invention-

[0029] The present application can perform shape measurement of a measurement object with high accuracy regardless of the kind of the measurement object. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a schematic diagram of a three-dimensional coordinate measuring machine.

[0031] Figure 2 is an enlarged perspective view of a probe head and a probe.

[0032] Figure 3 is a sectional view of a probe on which a first probe tip portion for non-contact measurement is mounted.

[0033] Figure 4 is an explanatory diagram for explaining a mounting configuration of the first probe tip portion and the second probe tip portion with respect to a mounting shaft.

[0034] Figure 5 is a sectional view of a probe on which a second probe tip portion for contact measurement is mounted.

[0035] Figure 6 is Figure 5 is an enlarged sectional view of the second probe tip portion.

[0036] Figure 7 is an enlarged sectional view of a modification of the second probe tip portion.

[0037] Figure 8 is an explanatory diagram for explaining a relationship between a refractive index of the probe sphere and a back focal length.

[0038] Figure 9 is an explanatory diagram for explaining detection of an interference signal by the light detector in a case where the first probe tip portion is mounted on the probe.

[0039] Figure 10 is an explanatory diagram for explaining detection of an interference signal by the light detector in a case where the second probe tip portion is mounted on the probe.

[0040] Figure 11 is an explanatory diagram for explaining functions of the controller and the control device.

[0041] Figure 12 is an explanatory view for explaining the function of the contact detection section and the relationship information acquired by the information acquisition section.

[0042] Figure 13 is an explanatory view for explaining an example of a method of generating relationship information.

[0043] Figure 14 is a flowchart showing a flow of a shape measurement process of a measurement surface of a workpiece using a three-dimensional coordinate measuring machine.

[0044] Figure 15 is an explanatory view for explaining a problem of a conventional contact measurement probe. DETAILED DESCRIPTION

[0045] [Structure of three-dimensional coordinate measuring machine]

[0046] Figure 1 is a schematic view of a three-dimensional coordinate measuring machine 10 corresponding to the shape measurement apparatus of the present application. In addition, Figure 1 the XYZ axes orthogonal to each other in the three-dimensional coordinate measuring machine 10 shown in

[0047] As shown in Figure 1 , the three-dimensional coordinate measuring machine 10 uses a probe 26 corresponding to both non-contact measurement and contact measurement to perform shape measurement of a workpiece W as a measurement target object of the present application. In addition, the shape of the workpiece W referred to herein includes various dimensional shapes such as length and diameter, in addition to three-dimensional shape, two-dimensional shape, surface shape, and profile shape of the workpiece W. Further, the shape and kind of the measurement target workpiece W are not particularly limited.

[0048] The three-dimensional coordinate measuring machine 10 includes a stand 12, a worktable 14 (a stage) provided on the stand 12, right and left Y carriages 16R and 16L erected on both end portions of the worktable 14, and an X guide 18 connecting upper portions of the right and left Y carriages 16R and 16L. A portal frame 19 is constituted by the right and left Y carriages 16R and 16L and the X guide 18.

[0049] On the upper surface and side surface of both end portions of the worktable 14 in the X direction, sliding surfaces along which the right and left Y carriages 16R and 16L slide are formed. In addition, air bearings (not shown) are provided at positions opposed to the sliding surfaces of the worktable 14 in the right and left Y carriages 16R and 16L. Thus, the right and left Y carriages 16R and 16L are movable together with the X guide 18 in the Y direction.

[0050] An X-carriage 20 is installed on the X-guide 18. The X-guide 18 forms a sliding surface on which the X-carriage 20 slides in the X direction. Further, an air bearing (omitted from the drawing) is provided on the X-carriage 20 at a position opposite to the sliding surface of the X-guide 18. Thus, the X-carriage 20 is freely movable in the X direction.

[0051] A Z-carriage 22 (also referred to as a Z-spindle) is installed on the X-carriage 20. Further, an air bearing for Z-directional guidance (not shown) is provided on the X-carriage 20 to guide the Z-carriage 22 in the Z direction. Thus, the Z-carriage 22 is held by the X-carriage 20 so as to be movable in the Z direction. A probe head 24 that selectively holds various probes including a probe 26 of the present application is provided on a lower end portion of the Z-carriage 22.

[0052] Further, in the three-dimensional coordinate measuring machine 10, as will be described later Figure 11 , a Y-drive 27Y that moves the door-type frame 19 in the Y direction, an X-drive 27X that moves the X-carriage 20 in the X direction, and a Z-drive 27Z that moves the Z-carriage 22 in the Z direction are provided. Thus, the probe head 24 (the probe 26) is movable in the XYZ directions.

[0053] Further, although omitted from the drawing, a Y-linear scale is provided on an end portion of the right Y-carriage 16R side of the table 14, an X-linear scale is provided on the X-guide 18, and a Z-linear scale is provided on the Z-carriage 22. Further, a detection section, i.e., an XYZ detection section 29A (refer to Figure 11 ) that reads the XYZ linear scales, respectively, is provided in the three-dimensional coordinate measuring machine 10. The detection results of the XYZ detection section 29A are output to a control device 72 via a controller 70.

[0054] Figure 2 is an enlarged perspective view of the probe 26 that is installed with the probe head 24 and the second probe tip portion 60. As shown in Figure 2 , the probe head 24 is, for example, a 5-axis simultaneous control head that is provided with a stepless positioning mechanism. A head rotation drive 27R (refer to Figure 11 ) that rotates the probe 26 in an axis direction θ1 of a rotation axis parallel to the Z direction and an axis direction θ2 of a rotation axis perpendicular to the Z direction, for example, a motor, is provided in the probe head 24. The head rotation drive 27R, together with the aforementioned respective drives 27X, 27Y, 27Z, constitutes a displacement mechanism of the present application.

[0055] Further, a rotation angle detection section 29B (refer to Figure 11 ) that detects the rotation angles of the probe 26 in the axis directions θ1, θ2, for example, a rotary encoder, is provided in the probe head 24. The detection results of the rotation angle detection section 29B are output to the control device 72 via the controller 70.

[0056] The probe 26 is detachably attached to the probe head 24. As shown in Figure 1 the first probe tip 50 for non-contact measurement and the second probe tip 60 for contact measurement are selectively attachable to the front end portion of the probe 26. Thus, by attaching either the first probe tip 50 or the second probe tip 60 to the front end portion of the probe 26, non-contact measurement or contact measurement of the shape of the workpiece W can be selectively performed.

[0057] When the first probe tip 50 is attached to the front end portion of the probe 26, the measurement light LA input from the wavelength-swept light source 28 via the optical fiber cable 30, the optical fiber circulator 32, and the optical fiber cable 33 is emitted toward the measurement surface of the workpiece W by the probe 26. Further, the probe 26 receives the reflected light LB reflected at the measurement surface of the workpiece W and outputs the reflected light LB and the reference light LC (described later) to the light detector 36 via the optical fiber cable 33, the optical fiber circulator 32, and the optical fiber cable 34. Figure 9

[0058] As described in detail later, the second probe tip 60 is hollow and provided with a probe ball 65 at the front end portion thereof.

[0059] Figure 3 is a cross-sectional view of the probe 26 to which the first probe tip 50 for non-contact measurement is attached. As shown in Figure 3 the probe 26 has a major axis MA and the first probe tip 50 is rotatable in the around-axis direction θ3 of the major axis MA (optical axis of the optical path LP described later). The probe 26 has, in addition to the probe main body portion 40, the optical fiber connecting portion 42, the attachment shaft 46, and the hollow motor 47, the first probe tip 50 and the second probe tip 60 (refer to Figure 5 ) selectively attachable to the attachment shaft 46.

[0060] The probe main body portion 40 is formed in a substantially cylindrical shape extending in the direction of the major axis MA and has a main body portion base end portion 40a and a main body portion front end portion 40b having a smaller diameter than the main body portion base end portion 40a. The optical fiber connecting portion 42 is provided projecting from the side surface of the main body portion base end portion 40a in the major axis perpendicular direction perpendicular to the major axis MA. Further, the beam splitter holding portion 41, the beam splitter 44, the light-receiving element 45, the attachment shaft 46, and the hollow motor 47 are provided inside the main body portion base end portion 40a.

[0061] The optical fiber connecting portion 42 has the front end portion of the optical fiber cable 33 connected to one end side thereof and holds the collimator lens 43 at the other end side thereof. In addition, the base end portion of the optical fiber cable 33 on the side opposite to the front end portion is inserted through the inside of the probe head 24 and the inside of the Z-carriage 22 and the like and connected to the optical fiber circulator 32.

[0062] ​The front end surface of the front end portion of the optical fiber cable 33, that is, the cable front end surface 33a, corresponds to the light incident / emergent portion of the present application. The cable front end surface 33a functions as an emergent surface that emerges the measurement light LA input to the optical fiber cable 33 from the wavelength-swept light source 28 via the fiber circulator 32 or the like in a direction perpendicular to the long axis, and functions as an incident surface that the reflected light LB of the measurement light LA is incident to.

[0063] The collimator lens 43 causes the measurement light LA (diffused light) that emerges from the cable front end surface 33a to be parallel light, and then emerges toward the beam splitter 44 described later. In addition, the collimator lens 43 causes the reflected light LB that is incident from the beam splitter 44 to converge and be incident to the cable front end surface 33a.

[0064] The beam splitter holding portion 41 holds the beam splitter 44 at a position where the optical axis of the collimator lens 43 intersects with the extension line of the long axis MA. In addition, the beam splitter holding portion 41 holds the light receiving element 45 at a position that opposes the third surface 44c of the beam splitter 44 described later.

[0065] The beam splitter 44 corresponds to the light splitting element of the present application, and splits light (measurement light LA, reflected light LB) that is incident to the beam splitter 44 and emerges in different directions. The beam splitter 44 is formed in a substantially cubic shape, and has a first surface 44a, a second surface 44b that connects to the first surface 44a and is perpendicular to the first surface 44a, and a third surface 44c.

[0066] The first surface 44a is an opposing surface that is perpendicular to the optical axis of the collimator lens 43 and opposes the collimator lens 43. The second surface 44b is a surface that is perpendicular to the long axis MA, and is a surface that faces the front end side of the long axis MA. The third surface 44c is a surface that is perpendicular to the long axis MA, and is a surface that is located on the opposite side of the second surface 44b in the beam splitter 44.

[0067] The beam splitter 44 splits the measurement light LA that is incident to the first surface 44a from the cable front end surface 33a via the collimator lens 43, and emerges a portion of the measurement light LA from the second surface 44b. The reflected light LB of the measurement light LA that emerges from the second surface 44b is incident to the second surface 44b. In addition, the reference sign LP in the drawing indicates the optical path of the measurement light LA that emerges from the second surface 44b and the reflected light LB that is incident to the second surface 44b.

[0068] In addition, the beam splitter 44 splits the reflected light LB that is incident to the second surface 44b, and emerges a portion of the reflected light LB from the first surface 44a toward the collimator lens 43 (cable front end surface 33a), and emerges the remaining portion of the reflected light LB from the third surface 44c toward the light receiving element 45.

[0069] The light-receiving element 45 is held by the beam splitter holding portion 41 at a position opposite the third surface 44c, for example, using a position sensitive detector (PSD) or a two-dimensional image sensor. The light-receiving element 45 has a light-receiving surface that receives the reflected light LB that exits from the third surface 44c. Also, the light-receiving element 45 outputs, to the control device 72 via the controller 70, an incident position coordinate that indicates the incident position of the reflected light LB on the light-receiving surface.

[0070] The mounting shaft 46 corresponds to the front end portion mounting portion of the present application. The mounting shaft 46 is a cylinder that passes through the inside of the main body portion front end portion 40b along the long axis MA from the inside of the main body portion base end portion 40a and protrudes to the front end side thereof, and has an inner surface that surrounds the optical path LP. An opening portion of the base end side of this mounting shaft 46 opposes the second surface 44b. On the other hand, a substantially annular front end flange F1 is formed on the opening peripheral portion of the front end side of the mounting shaft 46.

[0071] Furthermore, the mounting shaft 46 is held by the probe main body portion 40 so as to be rotatable in the axis direction θ3. Specifically, the base end portion of the mounting shaft 46 is held by the hollow motor 47, which will be described later, so as to be rotatable in the axis direction θ3 in the inside of the main body portion base end portion 40a. Furthermore, the front end portion of the mounting shaft 46 is held rotatable in the axis direction θ3 in the inside of the main body portion front end portion 40b via the bearing 49.

[0072] Figure 4 is an explanatory view for explaining the mounting configuration of the first probe front end portion 50 and the second probe front end portion 60 with respect to the mounting shaft 46. As shown in Figure 4 the front end flange F1 is selectively connected to the base end flange F2 that is formed on the base end side of each of the first probe front end portion 50 and the second probe front end portion 60, which will be described later. For example, one of the front end flange F1 and the base end flange F2 is formed by a magnet, and the other is formed by a metal, whereby the base end flange F2 is detachably connected to the front end flange F1. Alternatively, the base end flange F2 can be connected to the front end flange F1 by a screw or the like. Furthermore, a groove or a protrusion or the like for positioning is formed on the mutually opposing surfaces of the front end flange F1 and the base end flange F2. Thus, the first probe front end portion 50 and the second probe front end portion 60 can be selectively mounted with respect to the mounting shaft 46.

[0073] Returning to Figure 3The hollow motor 47 corresponds to the rotating mechanism of the present application, and rotates the mounting shaft 46 in the axial direction θ3. The hollow motor 47 has a hollow stator 47a (also referred to as a fixed member) and a hollow rotor 47b (also referred to as a rotating member). The stator 47a is fixed to the inner wall surface of the base end portion 40a of the main body portion. The rotor 47b is provided in the internal space of the stator 47a, and is further fitted and fixed to the outer peripheral surface of the mounting shaft 46. The rotor 47b rotates in the axial direction θ3 in conjunction with the mounting shaft 46. In addition, the detailed configuration of the hollow motor 47 is a publicly known technology, and thus the detailed description thereof is omitted.

[0074] The first probe front end portion 50 has a hollow first shaft 51, an optical system holding portion 53, an imaging lens 54, and a right-angle prism mirror 55. The base end flange F2 (corresponding to the first base end portion of the present application) described above is formed on the opening peripheral portion of the base end side of the first shaft 51, and the optical system holding portion 53 (corresponding to the first front end portion of the present application) is provided on the front end side of the first shaft 51. In the case where the base end flange F2 is connected to the front end flange Fl, that is, in the case where the first probe front end portion 50 is mounted to the mounting shaft 46, the first shaft 51 is a cylinder that forms the optical path LP (surrounds the optical path LP).

[0075] The optical system holding portion 53 holds the imaging lens 54 and the right-angle prism mirror 55 in the inside thereof. The imaging lens 54 is disposed at a position such that the optical axis thereof coincides with the optical axis (center line) of the optical path LP. The imaging lens 54 causes the measurement light LA, which has passed through the inside of the mounting shaft 46 and the first shaft 51 from the second face 44b, to be imaged on the measurement face of the workpiece W via the right-angle prism mirror 55. In addition, the imaging lens 54 causes the reflected light LB from the workpiece W, which has passed through the right-angle prism mirror 55, to be emitted toward the second face 44b.

[0076] The right-angle prism mirror 55 corresponds to the optical element and the reflecting element of the present application, and reflects the measurement light LA, which has been incident from the imaging lens 54, toward the measurement face of the workpiece W. Specifically, the right-angle prism mirror 55 causes the measurement light LA, which has been incident from the imaging lens 54, to be refracted by 90° (including approximately 90°) and emitted toward the measurement face of the workpiece W.

[0077] In addition, the right-angle prism mirror 55 reflects the reflected light LB, which has been incident from the measurement face of the workpiece W, toward the imaging lens 54. Thereby, the reflected light LB is incident on the second face 44b from the right-angle prism mirror 55 via the imaging lens 54, the inside of the first shaft 51, and the inside of the mounting shaft 46, and is further subjected to light splitting by the beam splitter 44, and is emitted from the first face 44a and the third face 44c, respectively. As a result, the reflected light LB is incident on the collimator lens 43 (the cable front end face 33a) and the light receiving face of the light receiving element 45, respectively.

[0078] The right-angle prism mirror 55 is integrally rotated in the axis direction θ3 with the mounting shaft 46 and the first shaft 51 by the hollow motor 47 described above. Thus, the measurement light LA can be rotationally scanned along the measurement surface of the workpiece W.

[0079] In addition, various reflection elements such as a mirror can be used instead of the right-angle prism mirror 55.

[0080] Figure 5 is a cross-sectional view of the probe 26 to which the second probe tip 60 for contact measurement is attached. Figure 6 is Figure 5 is an enlarged cross-sectional view of the second probe tip 60. As Figure 5 and Figure 6 shown, the second probe tip 60 is provided with a hollow second shaft 61, a probe ball holding portion 63 (see Figure 6 ), a corner prism 64, and a probe ball 65.

[0081] The base end flange F2 described above is formed on the opening peripheral portion of the base end side of the second shaft 61 (corresponding to the second base end portion of the present application), and the probe ball holding portion 63 (corresponding to the second tip portion of the present application) is provided on the tip side of the second shaft 61. In the case where the base end flange F2 is connected to the tip flange Fl, that is, in the case where the second probe tip 60 is attached to the mounting shaft 46, the second shaft 61 is a cylinder that forms the optical path LP (encompassing the optical path LP).

[0082] The probe ball holding portion 63 is formed in a substantially cylindrical shape, holds the corner prism 64 inside thereof, and holds the probe ball 65 on the tip portion thereof.

[0083] The corner prism 64 corresponds to the retroreflective element of the present application. The corner prism 64 retroreflects the measurement light LA that has entered from the second surface 44b through the inside of the mounting shaft 46 and the second shaft 61, and causes the reflected light LB to be incident on the second surface 44b. In addition, various retroreflective elements other than the corner prism 64 can be used as long as the measurement light LA can be retroreflected.

[0084] The probe ball 65 corresponds to the tip ball of the present application, and comes into contact with the measurement surface of the workpiece W at the time of contact measurement of the workpiece W.

[0085] Figure 7 is an enlarged cross-sectional view of a modification example of the second probe tip 60. In the example shown in Figure 5 and Figure 6 , the measurement light LA is retroreflected by the corner prism 64, but the measurement light LA can be retroreflected by other methods. For example, as Figure 7As shown, instead of the corner prism 64 and the probe ball 65, a probe ball 65A can be provided in the probe ball holding portion 63.

[0086] The probe ball 65A is formed of, for example, a glass material (various optical materials other than glass materials can also be used), and functions as a retroreflective ball lens as a retroreflective element. Thus, the probe ball 65A retroreflects the measurement light LA that has entered from the second face 44b through the inside of the mounting shaft 46 and the first shaft 51, and causes the reflected light LB to be incident on the second face 44b. Thus, the measurement light LA that has entered from the second face 44b is guided to the first face 44a via the probe ball 65A, the mounting shaft 46, and the first shaft 51. Figure 5 Figure 6 As compared with the example shown in FIG. 8, the number of components of the second probe tip portion 60 can be reduced, and thus the second probe tip portion 60 can be made less expensive.

[0087] Figure 8 is an explanatory view for explaining the relationship between the refractive index of the probe ball 65A and the back focal length BFL. Note that the reference numeral P in the drawing is a straight line that passes through the center of the probe ball 65A and is perpendicular to the optical path LP (the major axis MA).

[0088] As shown in the reference numeral 8A in FIG. 8, in a case where the outer diameter (diameter) of the probe ball 65A is "D" and the refractive index of the glass material that forms the probe ball 65A is "n", the focal length EFL of the probe ball 65A is expressed by the following [Math. 1], and the back focal length BFL of the probe ball 65A is expressed by the following [Math. 2]. Figure 8 [Math. 1]

[0089]

[0090]

[0091] [Math. 2]

[0092]

[0093] Here, in a case where the refractive index n of the glass material that forms the probe ball 65A is n = 2, the focal length EFL becomes EFL = D / 2 based on the above [Math. 1]. Also, in a case where the focal length EFL is EFL = D / 2, the back focal length BFL is BFL = 0 based on the above [Math. 2].

[0094] Thus, as shown in the reference numeral 8B in FIG. 8, in a case where the refractive index n of the glass material that forms the probe ball 65A is n = 1.5, the focal length EFL of the probe ball 65A is EFL = 1.5D / 2, and the back focal length BFL of the probe ball 65A is BFL = 0.5D. Figure 8 ​​By setting the refractive index n of the probe ball 65A to n = 2, the back focal length BFL can be made "0" as shown by reference numeral 8B. Thereby, the measurement light LA incident to the probe ball 65A can be retro-reflected at the vertex TP on the front end side of the probe ball 65A (including the vicinity thereof). As a result, detection of the position coordinates of the probe ball 65A when the probe ball 65A is in contact with the measurement surface of the workpiece W becomes easy.

[0095] Figure 9 is a diagram for explaining detection of the interference signal SG by the light detector 36 in a case where the first probe front end portion 50 is attached to the probe 26. Figure 10 is a diagram for explaining detection of the interference signal SG by the light detector 36 in a case where the second probe front end portion 60 is attached to the probe 26. In addition, in Figure 10 , as has been described Figure 7 , a probe ball 65A is provided to the second probe front end portion 60 as shown.

[0096] As shown in Figure 9 and Figure 10 , the wavelength-swept light source 28 corresponds to the light source of the present application. This wavelength-swept light source 28 emits the measurement light LA to the fiber circulator 32 via the fiber cable 30 under the control of the control device 72. This measurement light LA is a wavelength-swept light in which the wavelength is changed in a sinusoidal manner in a fixed wavelength band at a fixed wavelength-swept period (a fixed wavelength-swept frequency).

[0097] The fiber circulator 32 is optically connected to the wavelength-swept light source 28 via the fiber cable 30, and is optically connected to the light detector 36 via the fiber cable 34, and is optically connected to the probe 26 via the fiber cable 33.

[0098] The fiber circulator 32 is, for example, a non-reciprocal type and is a single direction type device having three ports, and outputs the measurement light LA input from the wavelength-swept light source 28 via the fiber cable 30 to the fiber cable 33. Thereby, the measurement light LA from the wavelength-swept light source 28 is input to the probe 26. As a result, in a case where the first probe front end portion 50 is attached to the probe 26, the reflected light LB reflected by the measurement surface of the workpiece W and the reference light LC reflected by the cable front end face 33a (corresponding to the reflecting surface of the present application) are input to the fiber circulator 32 via the fiber cable 33 (refer to Figure 9 ).

[0099] On the other hand, in a case where the second probe front end portion 60 is attached to the probe 26, the reflected light LB retro-reflected by the probe ball 65A (or the corner prism 64) and the reference light LC reflected by the cable front end face 33a are input to the fiber circulator 32 via the fiber cable 33 (refer to Figure 10 ).

[0100] The fiber-optic circulator 32 outputs the interference signal SG of the reflected light LB input from the probe 26 and the reference light LC to the light detector 36 via the fiber-optic cable 34.

[0101] The light detector 36 corresponds to the interference signal detection section of the present application, and uses, for example, a silicon photodiode, an InGaAs (indium gallium arsenide) photodiode, a phototube, a photomultiplier tube, or the like. The light detector 36 converts the interference signal SG input from the fiber-optic circulator 32 via the fiber-optic cable 34 into an electric signal and amplifies it under the control of the control device 72, and outputs it to the control device 72. Thus, the control device 72 calculates the distance from the cable front end face 33a to the reflecting surface of the reflected light LB on the basis of the detection result of the interference signal SG by the light detector 36.

[0102] Specifically, the control device 72 calculates the distance sum total value of the distance LI from the cable front end face 33a to the beam splitter 44, the distance L2 from the beam splitter 44 to the right-angle prism mirror 55, and the distance L3 from the right-angle prism mirror 55 to the measurement surface of the workpiece W (refer to FIG. 2) in the case where the first probe front end portion 50 is attached to the probe 26. Figure 9 On the other hand, the control device 72 calculates the distance sum total value of the distance LI and the distance L2A from the beam splitter 44 to the probe ball 65A (or the corner prism 64) (refer to FIG. 3) in the case where the second probe front end portion 60 is attached to the probe 26. Figure 10 Further, the specific calculation method of the distance is a known technique (for example, Japanese Patent Application Publication No. 2016-024086 and Japanese Patent Application Publication No. 2018-084434), and thus a specific description is omitted here.

[0103] Further, in the present embodiment, the distance measurement is performed by using the optical interference method using the wavelength-swept light source 28, but the distance measurement can be performed by using other known optical interference methods.

[0104] Figure 11 is an explanatory diagram for explaining the functions of the controller 70 and the control device 72. As shown in Figure 11 the controller 70 drives each of the driving portions 27X, 27Y, 27Z, 27R according to the operation input from the operator in the case where the three-dimensional coordinate measuring machine 10 is in the manual measurement mode, and displaces the probe 26 to a position posture in which the non-contact measurement or the contact measurement of the position coordinates of the measurement points can be performed for each of the plurality of measurement points in the measurement surface of the workpiece W. Further, the controller 70 drives each of the driving portions 27X, 27Y, 27Z, 27R under the control of the control device 72 in the case where the three-dimensional coordinate measuring machine 10 is in the automatic measurement mode, and displaces the probe 26 to a position posture in which the non-contact measurement or the contact measurement of the position coordinates of the measurement points can be performed for each of the plurality of measurement points.

[0105] Further, in a case where the rotational scanning of the measurement light LA with respect to the measurement surface of the work W is performed at each measurement point in the non-contact measurement, the controller 70 drives the hollow motor 47 so that the first probe tip 50 rotates in the axis direction θ3.

[0106] Further, the controller 70 continuously outputs, to the control device 72, the XYZ coordinates of the probe 26 detected by the XYZ detector 29A, the rotational angles of the probe 26 in the axis directions θ1, θ2 detected by the rotational angle detector 29B, and the incident position coordinates of the reflected light LB with respect to the light receiving surface detected by the light receiving element 45.

[0107] The control device 72 integrally controls the operations of the respective units of the three-dimensional coordinate measuring machine 10. The control device 72 is provided with an arithmetic circuit composed of various processors and memories and the like. The various processors include a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), and a programmable logic device such as an SPLD (Simple Programmable Logic Device), a CPLD (Complex Programmable Logic Device), and an FPGA (Field Programmable Gate Array), and the like. In addition, the various functions of the control device 72 can be realized by one processor, or by a plurality of processors of the same kind or different kinds.

[0108] In the control device 72, a storage unit 74 is connected in addition to the wavelength-swept light source 28, the light detector 36, and the controller 70, and the like that have been described. In the storage unit 74, in addition to a control program not shown of the three-dimensional coordinate measuring machine 10, a measurement program 75 and relationship information 76, and the like are stored.

[0109] The measurement program 75 indicates the measurement path of the probe 26 at the time of the shape measurement of the work W [for example, the measurement order of each measurement point, the coordinate values of each measurement point, and the coordinate values of the movement path points, that is, intermediate points, of the probe 26, and the like]. In addition, the relationship information 76 will be described later.

[0110] The control device 72 functions as a drive control unit 80, an XYZ coordinate acquisition unit 81, an incident position coordinate acquisition unit 82, a rotation angle acquisition unit 83, a distance calculation unit 84, a first shape calculation unit 85, and a second shape calculation unit 90 by executing a control program (not shown) stored in the storage unit 74.

[0111] The drive control unit 80 operates when an automatic measurement mode (non-contact measurement, contact measurement) is selected. Based on the measurement program 75 stored in the storage unit 74, the drive control unit 80 drives each drive unit 27X, 27Y, 27Z, and 27R via the controller 70 to displace the position and posture of the probe 26 at each measurement point on the measurement surface of the workpiece W. This allows the probe 26 to be displaced at each measurement point to a position and posture suitable for non-contact or contact measurement of its position coordinates.

[0112] The XYZ coordinate acquisition unit 81 continuously acquires the detection results of the XYZ coordinates of the probe 26 (probe head 24) from the XYZ detection unit 29A via the controller 70.

[0113] The incident position coordinate acquisition unit 82 continuously acquires the detection results of the incident position coordinates of the reflected light LB on the light-receiving surface from the light-receiving element 45 via the controller 70.

[0114] The rotation angle acquisition unit 83 continuously acquires the detection results of the rotation angles of the probe 26 around the axis θ1 and θ2 from the rotation angle detection unit 29B via the controller 70.

[0115] The distance calculation unit 84 continuously performs the acquisition of the detection result of the interference signal SG from the photodetector 36 and the calculation of the distance from any reference position (the front end face 33a or the second face 44b of the cable) to the reflecting surface of the reflected light LB based on the interference signal SG.

[0116] For example, when the distance calculation unit 84 is at the aforementioned reference position of the cable tip face 33a, it continuously performs the previously described operations during non-contact measurement. Figure 9 The calculation of the total distance value (L1+L2+L3) shown is performed continuously during contact measurement, as described above. Figure 10 The calculation of the total distance value (L1+L2A) shown. In addition, when the reference position is the second surface 44b, the distance calculation unit 84 subtracts the known distance from the cable front end surface 33a to the second surface 44b from the total distance value.

[0117] The first shape calculation unit 85 operates when non-contact measurement is selected in both automatic and manual measurement modes. Whenever non-contact measurement is performed at each measurement point, the first shape calculation unit 85 calculates the position coordinates (XYZ coordinates) of the measurement point based at least on the XYZ coordinates of the probe 26 obtained by the XYZ coordinate acquisition unit 81, the rotation angles around the axis directions θ1 and θ2 obtained by the rotation angle acquisition unit 83, and the distance calculated by the distance calculation unit 84. Therefore, the first shape calculation unit 85 calculates the shape of the measurement surface of the workpiece W based on the calculation results of the position coordinates of each measurement point. Furthermore, the method for calculating the shape of the measurement surface of the workpiece W based on non-contact measurement is known technology (see Patent Document 2 above), so a detailed description is omitted here.

[0118] The second shape calculation unit 90 operates when contact measurement is selected among the two measurement modes. This second shape calculation unit 90 functions as a contact detection unit 91, an information acquisition unit 92, a probe spherical coordinate calculation unit 93, and a shape calculation unit 94.

[0119] Figure 12 This is an explanatory diagram illustrating the function of the contact detection unit 91 and the relationship information 76 acquired by the information acquisition unit 92. Additionally, the X in the diagram... W Y W Z W shaft and Figure 1 The XYZ axes shown are the same, indicating a mechanical coordinate system determined based on the inherent mechanical coordinate origin of the three-dimensional coordinate measuring machine 10. Furthermore, the X... P Y P Z P The axis is a probe coordinate system with probe 26 as the reference. X P Y P The direction of the axis represents the two-dimensional direction of the light-receiving surface of the light-receiving element 45, Z. P The direction of the axis indicates the direction of the major axis MA (the emission direction of the measuring light LA ​​from the second surface 44b).

[0120] Furthermore, the reference numeral V1 in the figure indicates the position coordinates (x, y, z) of the probe 26 in the mechanical coordinate system obtained by the XYZ coordinate acquisition unit 81. w y w , z w Furthermore, reference numeral V2 in the figure indicates the incident position coordinates (x, y) of the reflected light LB in the probe coordinate system (within the light-receiving surface of the light-receiving element 45) obtained by the incident position coordinate acquisition unit 82. p y p Furthermore, the reference numeral V3 in the figure represents the distance calculation result V3 (z) in the probe coordinate system calculated by the distance calculation unit 84. p ).

[0121] As Figure 12 and the Figure 11 The contact detection section 91 operates in the driving of each driving section 27X, 27Y, 27Z, 27R (in the displacement of the position or posture of the probe 26). This contact detection section 91 detects whether or not the probe ball 65, 65A is in contact with each measurement point based on the incident position coordinates V2(x p , y p ) continuously acquired by the incident position coordinate acquisition section 82 and the distance calculation result V3(z p ) continuously calculated by the distance calculation section 84.

[0122] For example, the contact detection section 91 sets a threshold range for the incident position coordinates V2(x p , y p ) and the distance calculation result V3(z p ), and detects whether or not the probe ball 65, 65A is in contact with each measurement point based on whether or not the incident position coordinates V2(x p , y p ) and the distance calculation result V3(z p ) are outside the threshold range.

[0123] Further, the contact detection section 91 can also set a threshold range for the time differential values of the incident position coordinates V2(x p , y p ) and the distance calculation result V3(z p ), and detect whether or not the probe ball 65, 65A is in contact with each measurement point based on whether or not the time differential values of the incident position coordinates V2(x p , y p ) and the distance calculation result V3(z p ) are outside the threshold range.

[0124] Further, in the case of performing the profile measurement of the measurement surface of the workpiece W using the second probe tip 60, a threshold is set for the incident position coordinates V2(x p , y p ) and the distance calculation result V3(z p ). Then, the contact detection section 91 can also perform the time sampling of the incident position coordinates V2(x p , y p ) and the distance calculation result V3(z p ) in the case where they become equal to or greater than the threshold, and detect whether or not the probe ball 65, 65A is in contact with each measurement point based on the result of the time sampling.

[0125] The information acquisition section 92 acquires the relationship information 76 from the storage section 74 in advance. The relationship information 76 is information indicating the X W YW Z W directions of the probe coordinate system with the probe 26 as a reference P Y P Z P directions. The relationship information 76 is generated in advance and stored in the storage section 74 (may be an external server).

[0126] Figure 13 is an explanatory diagram for explaining an example of a method of generating the relationship information 76. In addition, in Figure 13 , as already described Figure 7 , a probe ball 65A is provided at the second probe tip portion 60.

[0127] As shown in Figure 13 , first, the probe ball 65A or the corner prism 64 is removed from the probe 26. Then, the probe ball 65A or the corner prism 64 removed from the probe 26, or the same object as them is placed on the work table 14.

[0128] Next, while displacing the position and posture of the probe 26 in the state where the second probe tip portion 60 is removed N (N is a natural number of 4 or more) times, non-contact measurement (irradiation of the measurement light LA, and reception of the reflected light LB) of the probe 26 with respect to the probe ball 65A or the corner prism 64 is performed at N positions. Thereby, at each of the N positions, the position coordinates V1 (x w , y w , z w ) of the probe 26, the incident position coordinates V2 (x p , y p ), and the distance calculation result V3 (z p ) are obtained (sampled).

[0129] If any one of the sets of the N position coordinates V1 (x w , y w , z w ), the incident position coordinates V2 (x p , y p ), and the distance calculation result V3 (z p ) is set as a reference n = 0, the following [Math. 3] is established for n = 1 to N.

[0130] [Math. 3]

[0131]

[0132] If the above [Math. 3] is solved by the least square method using the sampled values for n = 1 to N, the relationship between the directions of the mechanical coordinate system and the probe coordinate system with the probe 26 as a reference is expressed by the following [Math. 4]. The relationship information 76 is generated in advance and stored in the storage section 74 (may be an external server). W Y W ZW Direction and X of the probe coordinate system P Y P Z P Given the relational information 76 of the direction, find the "R" in [Mathematical Formula 3].

[0133] Furthermore, the above [Mathematical Formula 3] can be replaced with the following [Mathematical Formula 4] for the purpose of reducing the impact of the error of overlapping with the reference n=0. This [Mathematical Formula 4] can be solved by the least squares method using all combinations of n=0 to N and m=0 to N (where n≠m).

[0134] [Mathematical Expression 4]

[0135]

[0136] return Figure 11 The spherical coordinate calculation unit 93 corresponds to the front-end spherical coordinate calculation unit of the present invention, and obtains the relationship information 76 in advance from the information acquisition unit 92. Furthermore, whenever the contact detection unit 91 detects contact between the probe balls 65, 65A and each measurement point, the spherical coordinate calculation unit 93 executes the position coordinate V1(x, y, z) obtained from the XYZ coordinate acquisition unit 81. w y w , z w The acquisition of the incident position coordinates V2 (x) from the incident position coordinate acquisition unit 82. p y p The acquisition of ) and the distance calculation result V3 (z) from the distance calculation unit 84. p The acquisition of ).

[0137] Furthermore, the probe spherical coordinate calculation unit 93 is based on the position coordinate V1(x) w y w , z w ), incident position coordinates V2 (x p y p ), Distance calculation result V3 (z p Using the relationship information 76(R), the position coordinates (x, y, z) of the probe balls 65 and 65A in the mechanical coordinate system are calculated using the following [Mathematical Formula 5]. Additionally, [x0, y0, z0] in [Mathematical Formula 5]... T This refers to the offset coordinates from the origin of the mechanical coordinate system to the probe balls 65 and 65A during non-contact measurement. Alternatively, without using a probe head 24 or multiple probes capable of changing the orientation of the probe 26, it can also be [x0, y0, z0]. T [0, 0, 0] T .

[0138] [Mathematical Expression 5]

[0139]

[0140] The shape calculation unit 94 calculates the shape of the measurement surface of the workpiece W based on the calculation results of the position coordinates (x, y, z) of the probe balls 65, 65A at each measurement point of the probe ball coordinate calculation unit 93.

[0141] [The function of a 3D measuring machine]

[0142] Figure 14 This is a flowchart illustrating the process of shape measurement of the measurement surface of workpiece W performed by the three-dimensional coordinate measuring machine 10 with the aforementioned structure. For example... Figure 14 As shown, when the inspector selects non-contact measurement of the measurement surface of workpiece W, the front end 50 of the first probe is mounted on the probe 26 (no in step S1, steps S2 and S3). Next, non-contact measurement of multiple measurement points within the measurement surface of workpiece W is performed using a known method (step S4), and the shape of the measurement surface of workpiece W is calculated by the first shape calculation unit 85 (step S5).

[0143] On the other hand, when the inspector selects to measure the contact surface of the workpiece W, the front end 60 of the second probe is installed on the probe 26 (yes in step S1, step S6).

[0144] Next, by starting the emission of the measurement light LA ​​from the wavelength sweep light source 28 (step S7), the light receiving of the reflected light LB from the light receiving element 45 and the incident position coordinates V2 (x) of the incident position coordinate acquisition unit 82 are started. p y p The acquisition of ) (step S8). Furthermore, simultaneously, the detection of the interference signal SG of the start photodetector 36 and the distance calculation result V3(z) of the distance calculation unit 84 are performed. p ) operation (step S9).

[0145] Next, based on the input operation to the controller 70, each drive unit 27X, 27Y, 27Z, 27R is driven (manual measurement mode), or the drive control unit 80 drives each drive unit 27X, 27Y, 27Z, 27R based on the measurement program (automatic measurement mode), so that the probe 26 is moved to a position posture where the initial measurement point contact measurement can be performed (step S10).

[0146] Furthermore, when the displacement of probe 26 begins, the contact detection unit 91 continuously acquires the incident position coordinates V2 (x) based on the incident position coordinate acquisition unit 82. p y p The distance calculation result V3 (z) is continuously calculated by the distance calculation unit 84 and the distance calculation unit 84. p), to detect whether the probe ball 65, 65A is in contact with the initial measurement point (NO in step Sll). Thus, without using the sensor 204 (refer to FIG. 2) of the strain gauge of the related art, or without additionally providing a complicated detection device, it is possible to optically detect whether the probe ball 65, 65A is in contact with the measurement point. Figure 15

[0147] When the contact detection section 91 detects the contact of the probe ball 65, 65A to the initial measurement point (YES in step Sll), the probe ball coordinate calculation section 93 operates. In addition, the probe ball coordinate calculation section 93 previously acquires the relationship information 76 from the storage section 74. Further, the probe ball coordinate calculation section 93 performs the acquisition of the position coordinates VI (x w , y w , z w ) from the XYZ coordinate acquisition section 81, the acquisition of the incident position coordinates V2 (x p , y p ) from the incident position coordinate acquisition section 82, and the acquisition of the distance calculation result V3 (z p ) from the distance calculation section 84.

[0148] Next, the probe ball coordinate calculation section 93 calculates the position coordinates (x, y, z) of the probe ball 65, 65A based on the position coordinates VI (x w , y w , z w ), the incident position coordinates V2 (x p , y p ), the distance calculation result V3 (z p ), and the relationship information 76 (R), using the above [Math. 5], (step S12). Thus, the contact measurement of the initial measurement point ends.

[0149] Hereinafter, for each of the remaining measurement points, the displacement of the position and posture of the probe 26 corresponding to the measurement point (step S10), the detection of the contact of the probe ball 65, 65A to the measurement point by the contact detection section 91 (step Sll), and the calculation of the position coordinates (x, y, z) by the probe ball coordinate calculation section 93 (step S12) are repeatedly performed (YES in step S13).

[0150] When the calculation of the position coordinates (x, y, z) of all the measurement points by the probe ball coordinate calculation section 93 is completed (NO in step S13), the shape calculation section 94 calculates the shape of the measurement surface of the workpiece W based on the calculation results of the position coordinates (x, y, z) of each of the measurement points (step S14).

[0151] ​As described above, in the three-dimensional coordinate measuring machine 10 of the present embodiment, by enabling the probe 26 to selectively mount the first probe tip portion 50 for non-contact measurement and the second probe tip portion 60 for contact measurement, non-contact measurement and contact measurement of the measurement surface of the workpiece W can be selectively performed. In the case where non-contact measurement is selected, the problems in the conventional contact measurement (deflection of the probe and radius correction error of the probe ball) do not occur, and thus the shape measurement of the measurement surface can be performed with high accuracy.

[0152] Further, in the three-dimensional coordinate measuring machine 10 of the present embodiment, in the case where the measurement surface of the workpiece W is a mirror surface having a small roughness that is not suitable for non-contact measurement, contact measurement can be selected to perform the shape measurement of the measurement surface. Furthermore, in the case where contact measurement is selected, that is, in the case where the second probe tip portion 60 is mounted to the probe 26, the position coordinates of the measurement points can be obtained based on the position coordinates VI of the probe 26 obtained by the XYZ coordinate obtaining portion 81, the incident position coordinates V2 of the reflected light LB obtained by the incident position coordinate obtaining portion 82, and the distance calculation result V3 of the distance calculation portion 84. Thus, in the contact measurement of the present embodiment, the deflection of the probe 26 and the generation of the radius correction error of the probe balls 65, 65A do not need to be considered, the shape measurement of the measurement surface can be performed with high accuracy, and further, the above-described Figure 15 Specific studies such as the fulcrum portion 203 shown in the drawing.

[0153] Thus, in the three-dimensional coordinate measuring machine 10 of the present embodiment, by selecting the first probe tip portion 50 or the second probe tip portion 60 according to the type of the workpiece W, the shape measurement of the workpiece W can be performed with high accuracy regardless of the type of the workpiece W.

[0154] [Others]

[0155] In the above-described embodiment, the right-angle prism mirror 55 is held to the optical system holding portion 53 of the first probe tip portion 50, but the right-angle prism mirror 55 can be omitted, and the measurement light LA can be emitted from the imaging lens 54 to the front side thereof along the major axis MA, and the reflected light LB reflected on the measurement surface of the workpiece W can be incident to the imaging lens 54. In this case, the imaging lens 54 corresponds to the optical element of the present application.

[0156] In the above-described embodiment, the hollow motor 47 and the bearing 49 are provided to the probe 26, but the hollow motor 47 and the bearing 49 can be omitted.

[0157] In the above-described embodiments, the probe 26 can selectively mount the first probe tip portion 50 for noncontact measurement and the second probe tip portion 60 for contact measurement, but the probe 26 can also be made to correspond to only noncontact measurement or contact measurement. For example, in the case of making the probe 26 to correspond to only noncontact measurement, the mounting shaft 46 and the first probe tip portion 50 are integrated, or the mounting shaft 46 and the hollow motor 47 are omitted and the first probe tip portion 50 is fixedly arranged only on the front side of the second surface 44b. Further, in the case of making the probe 26 to correspond to only contact measurement, the mounting shaft 46 and the second probe tip portion 60 are integrated, or the mounting shaft 46 and the hollow motor 47 are omitted and the second probe tip portion 60 is fixedly arranged only on the front side of the second surface 44b.

[0158] In the above-described embodiments, the shape measurement device of the present application is exemplified by the three-dimensional coordinate measurement machine 10, but the present application can also be applied to a shape measurement device that measures the shape of various measurement objects using the probe 26.

[0159] -Explanation of Reference Numerals-

[0160] 10 … three-dimensional coordinate measuring machine, 12 … stand, 14 … worktable, 16L … left Y bracket, 16R … right Y bracket, 18 … X guide, 19 … door frame, 20 … X bracket, 22 … Z bracket, 24 … probe head, 26 … probe, 27R … head rotation driving section, 27X … X driving section, 27Y … Y driving section, 27Z … Z driving section, 28 … wavelength-swept light source, 29A … XYZ detecting section, 29B … rotation angle detecting section, 30 … optical fiber cable, 32 … optical fiber cable, 33 … optical fiber cable, 33a … cable front end face, 34 … optical fiber cable, 36 … light detector, 40 … probe main body section, 40a … main body section base end section, 40b … main body section front end section, 41 … beam splitter holding section, 42 … optical fiber connecting section, 43 … collimator lens, 44 … beam splitter, 44a … first face, 44b … second face, 44c … third face, 45 … light receiving element, 46 … mounting shaft, 47 … hollow motor, 47a … stator, 47b … rotor, 49 … bearing, 50 … first probe front end section, 51 … first shaft, 53 … optical system holding section, 54 … imaging lens, 55 … right-angle prism mirror, 60 … second probe front end section, 61 … second shaft, 63 … probe ball holding section, 64 … corner prism, 65, 65A … probe ball, 70 … controller, 72 … control device, 74 … storage section, 75 … measurement program, 76 … relationship information, 80 … driving control section, 81 … XYZ coordinate acquisition section, 82 … incident position coordinate acquisition section, 83 … rotation angle acquisition section, 84 … distance calculation section, 85 … first shape calculation section, 90 … second shape calculation section, 91 … contact detection section, 92 … information acquisition section, 93 … probe ball coordinate calculation section, 94 … shape calculation section, 200 … probe, 201 … stylus, 202 … probe ball, 203 … fulcrum section, 204 … sensor, BFL … back focal length, EFL … focal length, F1 … front end flange, F2 … base end flange, L1, L2, L2A, L3 … distance, LA … measurement light, LB … reflected light, LC … reference light, LP … optical path, MA … major axis, SG … interference signal, TP … apex, V1 … position coordinate, V2 … incident position coordinate, V3 … distance calculation result, W … workpiece, n … refractive index, θ1-θ3 … axis direction

Claims

1. A probe, characterized in that, have: The light incident and exit section emits measuring light and reflects the incident measuring light. A light splitting element has a first surface, a second surface, and a third surface. It splits the measurement light incident on the first surface from the light incident and exiting portion, so that a portion of the measurement light is emitted from the second surface. The reflected light of the measurement light emitted from the second surface is incident on the second surface. The reflected light incident on the second surface is split, so that a portion of the reflected light is emitted from the first surface toward the light incident and exiting portion. The remaining portion of the reflected light is emitted from the third surface. A light-receiving element receives the reflected light emitted from the third surface; as well as The front end mounting portion has an optical path for the measuring light emitted from the second surface and the reflected light incident on the second surface, and can selectively mount a first probe front end for non-contact measurement and a second probe front end for contact measurement. The front end of the first probe has: A hollow first shaft has a first front end portion and a first base end portion, and forms the optical path when the first base end portion is detachably mounted to the front end end portion mounting portion; and An optical element, disposed at the first front end, emits the measuring light, which enters through the interior of the first shaft from the second surface, toward the measuring object, and emits the reflected light, which is reflected by the measuring object, toward the second surface. The front end of the second probe has: The hollow second shaft has a second front end and a second base end, and the optical path is formed when the second base end is detachably mounted to the front end mounting portion. A front ball, located at the second front end, is in contact with the object being measured. as well as A retroreflective element retroreflects the measurement light incident from the second surface through the interior of the second shaft, so that the reflected light is incident on the second surface.

2. The probe according to claim 1, wherein, The optical element is a reflective element that reflects the measuring light incident from the second surface through the interior of the first shaft toward the measuring object and reflects the reflected light from the measuring object toward the second surface.

3. The probe according to claim 1, wherein, The retroreflective element is disposed inside the second front end.

4. The probe according to claim 1, wherein, The front sphere is a retroreflective spherical lens that functions as the retroreflective element.

5. The probe according to claim 4, wherein, The refractive index of the retroreflective spherical lens is 2.

6. The probe according to claim 1, wherein, The light-receiving element is a position detection sensor or a two-dimensional image sensor.

7. The probe according to any one of claims 1 to 6, wherein, The probe includes a collimating lens disposed between the light incident / exit portion and the first surface.

8. The probe according to any one of claims 1 to 6, wherein, The probe includes a rotation mechanism that, when the front end of the first probe is mounted on the front end mounting portion, rotates the front end mounting portion and the front end of the first probe in an axial direction centered on the optical axis of the optical path.

9. A shape measuring device for measuring the shape of an object, characterized in that, have: The probe according to any one of claims 1 to 6; A displacement mechanism capable of displacing the probe; The light source for measuring the light is optically connected to the light incident and exit section; as well as An interference signal detection unit is optically connected to the light incident and exiting unit, and detects the interference signal between the reflected light and the reference light incident on the light incident and exiting unit. The reference light is a portion of the measurement light reflected from a reflective surface that is different from the measurement object and the retroreflective element.

10. The shape measuring device according to claim 9, wherein, When the front end of the second probe is mounted on the front end mounting portion, the shape measuring device further comprises: The incident position coordinate acquisition unit continuously acquires the incident position coordinates of the reflected light on the light-receiving surface of the light-receiving element; The distance calculation unit continuously calculates the distance from a predetermined reference position to the retroreflective element based on the interference signal detected by the interference signal detection unit. as well as The contact detection unit detects the contact between the front ball and the object to be measured, based on the incident position coordinates continuously acquired by the incident position coordinate acquisition unit and the distance continuously calculated by the distance calculation unit during the driving of the displacement mechanism.

11. The shape measuring device according to claim 10, wherein, The displacement mechanism enables the probe to be displaced at least in the XYZ directions of the mechanical coordinate system of the shape measuring device. The shape measuring device includes: The XYZ coordinate acquisition unit acquires the XYZ coordinates of the probe in the mechanical coordinate system; and When the contact detection unit detects that the front ball is in contact with the object being measured, the front ball coordinate calculation unit calculates the XYZ coordinates of the front ball in the mechanical coordinate system based on the XYZ coordinates of the probe obtained by the XYZ coordinate acquisition unit, the incident position coordinates obtained by the incident position coordinate acquisition unit, and the distance calculated by the distance calculation unit.

12. The shape measuring device according to claim 11, wherein, The front-end spherical coordinate calculation unit pre-obtains information representing the relationship between the XYZ direction of the mechanical coordinate system, the two-dimensional direction of the light-receiving surface, and the emission direction of the measurement light from the second surface. Based on the XYZ coordinates of the probe, the incident position coordinates, the distance, and the information, it calculates the XYZ coordinates of the front-end sphere.

Images