Image measuring device

Abstract

To provide an image measuring device capable of avoiding the enlargement of the device and enhancing the ability to cope with a relatively large workpiece.SOLUTION: An image measuring device includes: a movable part provided on a support part supporting an imaging part above a stage and movable along an imaging axis of the imaging part; a housing which is fixed to the movable part and to which a stylus 83A having a contact part contacting with a workpiece is detachably attached; a stylus holding part 101 fixed to the support part and holding the stylus 83A; and an arm part 102 configured to move, while holding the stylus 83A, between an attachable position where the stylus 83A is made attachable to the housing and a retracted position where the stylus 83A is retracted from the attachable position.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present disclosure relates to an image measuring device that displays a workpiece image and measures the three-dimensional coordinates of the workpiece using a touch probe. [Background technology]

[0002] For example, Patent Document 1 discloses a coordinate measuring machine equipped with both an image probe that captures an image of a workpiece and measures the image, and a touch probe that contacts the workpiece on a stage and measures the three-dimensional coordinates of the contact point. The coordinate measuring machine in Patent Document 1 is equipped with a probe exchanger for exchanging the image probe and touch probe in a dedicated space on the stage on which the workpiece is placed, outside the actual measurement area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-145422 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the stylus of a touch probe has different overall shapes such as cross-shaped, L-shaped, T-shaped, etc., or different sizes of the probe ball at the tip, and is used depending on the object to be measured, the measurement purpose, etc. For this reason, the probe changer of Patent Document 1 may hold multiple different types of touch probes.

[0005] If the probe exchanger is installed in a dedicated space outside the actual measurement area, as in Patent Document 1, the moving stroke of the touch probe must be secured to be longer than the measurement area, which increases the length of the moving parts and leads to an increase in the size of the device.

[0006] It is also possible to install a probe exchanger on the stage on which the workpiece is placed, but if the probe exchanger is installed on the stage, it will get in the way when, for example, placing the workpiece on the stage, which will reduce the ability to handle large workpieces.

[0007] The present disclosure has been made in consideration of the above points, and its purpose is to provide an image measuring device that can prevent the device from becoming large and can improve its ability to handle relatively large workpieces. [Means for solving the problem]

[0008] In order to achieve the above object, an image measuring device according to one aspect of the present disclosure includes a base that movably supports a stage, a light-projecting unit that is provided on the base and that irradiates detection light onto a workpiece on the stage, an imaging unit that receives the detection light irradiated by the light-projecting unit and generates a workpiece image, a support unit that is connected to the base and that supports the imaging unit above the stage, a movable unit that is provided on the support unit and that is movable along the imaging axis of the imaging unit, a housing to which a stylus that is fixed to the movable unit and has a contact unit that comes into contact with the workpiece is detachably attached, a stylus holding unit that holds one or more styluses, an arm unit that is attached to the support unit and supports the stylus holding unit, and that moves the stylus held by the stylus holding unit between an attachable position that allows the stylus to be attached to the housing and a retracted position that retracts the stylus from the attachable position, and a control unit that controls the arm unit to move the stylus to the attachable position and the movable unit to lower the housing, thereby attaching the stylus to the housing.

[0009] With this configuration, the stylus held by the stylus holder is switched from the retracted position to the attachable position by the arm, and then the housing is lowered by the movable part, allowing the stylus to be attached to the housing. Therefore, the probe can be attached by operating the arm without having to ensure that the movable stroke of the touch probe is longer than the measurement area of ​​the workpiece, thereby avoiding an increase in the size of the device.

[0010] Furthermore, the arm portion that holds the stylus holder is attached to a support portion that supports the imaging portion above the stage, so the stylus holder does not get in the way when placing the work on the stage, and even relatively large workpieces can be easily placed on the stage.

[0011] The movable portion may also be configured to adjust the focus of the imaging portion, in which case the housing can be lowered using the focus adjustment mechanism when the stylus is attached to the housing.

[0012] The arm may also move the stylus in a direction perpendicular to the imaging axis. For example, the stylus holder may be provided at the tip of the arm, and a rotating unit may be attached to the support unit, connected to the base of the arm and configured to rotate the holder around a rotation axis parallel to the imaging axis. This allows the control unit to control the rotating unit so that the stylus is positioned at the mountable position.

[0013] Alternatively, the pivoting unit may be attached to the support unit so that the pivot axis is positioned between the stylus in the attachable position and the stylus in the retracted position. That is, by rotating the arm unit by, for example, 180° around the pivot axis, the stylus can be switched from the attachable position to the retracted position, and from the retracted position to the attachable position.

[0014] The device may also include a slider that slides the stylus holder in the axial direction of the arm. In this case, the control unit can control the slider so that the stylus is located in the attachment position. The control unit positions the stylus holder in the retracted position closer to the base end of the arm than the stylus holder in the attachment position. This makes it possible to make the arm in the retracted position even less of a hindrance.

[0015] Furthermore, when moving a stylus from a retracted position to an attachable position, the arm may be rotated by the rotating unit, and the stylus holder may be moved by the slider. If the stylus holder has at least two or more notched portions for holding different types of stylus, the slider may be controlled so that the stylus held in the desired notched portion is positioned at the attachable position.

[0016] The support portion may also include a canopy portion that covers at least a portion of the upper side of the stylus holder when in the retracted position, thereby making it less likely that the stylus holder will come into contact with surrounding members or the like by mistake. [Effects of the Invention]

[0017] As described above, the stylus is held by an arm attached to the support, and the stylus held by the arm can be moved between an attachable position and a retracted position. This eliminates the need to ensure that the movable stroke of the touch probe is larger than the measurement area, which prevents the device from becoming larger. In addition, the stylus holding portion does not get in the way when placing a workpiece on the stage, improving the device's ability to accommodate relatively large workpieces. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram showing the overall configuration of an image measuring device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view of the device body as seen from above. [Figure 3]FIG. 2 is a schematic diagram of the device body as viewed from the front side. [Figure 4] FIG. 2 is a schematic diagram of the device body as viewed from the side. [Figure 5] FIG. 2 is a perspective view of the light receiving lens and its vicinity as viewed obliquely from below. [Figure 6] FIG. 1 is a block diagram of an image measuring device. [Figure 7] FIG. 2 is a longitudinal sectional view of the touch probe. [Figure 8] FIG. 4 is a plan view of a fulcrum-forming elastic member. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 8 is a view corresponding to FIG. 7 showing another example of the touch probe. [Figure 11] FIG. 1 is a perspective view of a stylus changer mechanism. [Figure 12] FIG. [Figure 13] 10 is a flowchart illustrating an example of a procedure for attaching a stylus. [Figure 14] FIG. 14A is a perspective view showing the state in which the housing is placed above the stylus holding portion in the attachment position, and FIG. 14B is a perspective view showing the state in which the housing has been lowered and the stylus has been attached. [Figure 15] 10 is a flowchart illustrating an example of a procedure for removing the stylus. [Figure 16] 10 is a flowchart showing an example of a procedure for setting up the measurement of the image measuring device. [Figure 17] 10 is a flowchart illustrating an example of an image generation procedure. [Figure 18] 10 is a flowchart illustrating an example of a procedure for setting up image measurement. [Figure 19] 10 is a flowchart illustrating an example of a procedure for setting up coordinate measurement. [Figure 20] FIG. 2 is a perspective view of a workpiece on a stage. [Figure 21] This is a planar image of a stage on which a workpiece is placed. [Figure 22]FIG. 10 is a longitudinal cross-sectional view of the workpiece on the stage taken along the Y direction. [Figure 23] FIG. 10 is a diagram showing an example of a user interface screen for setting a contact target position. [Figure 24] FIG. 10 is a diagram showing an example of a user interface screen for setting a contact target position with respect to a slope. [Figure 25] 10 is a flowchart showing an example of a measurement procedure using a non-contact displacement meter. [Figure 26] FIG. 10 is a diagram showing an example of a user interface screen for displaying geometric elements. [Figure 27] FIG. 10 is a diagram showing an example of a user interface screen for superimposing and displaying geometric elements on a three-dimensional image. [Figure 28] 10 is a flowchart showing an example of a detailed procedure of a measurement operation of the touch probe. [Figure 29A] 10 is a flowchart showing an example of a first half of a procedure when setting up the image measuring device for measurement. [Figure 29B] 10 is a flowchart showing an example of a second half of the procedure when setting up the image measuring device for measurement. [Figure 30] 10 is a flowchart showing an example of a procedure for non-contact measurement when performing measurement. [Figure 31] 7 is a diagram corresponding to FIG. 6 according to Modification 1 having a three-channel imaging element. [Figure 32] 7A and 7B are diagrams corresponding to FIG. 6 and relating to a second modification having a single-channel imaging element and a three-channel imaging element. DETAILED DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] FIG. 1 is a diagram showing the overall configuration of an image measuring device 1 according to an embodiment of the present invention. The image measuring device 1 has an apparatus main body 2, a control unit 3 configured by a personal computer or the like, and a display unit 4. The control unit 3 processes data acquired by the apparatus main body 2 to measure the dimensions of various parts of the workpiece W, and is also configured to be able to perform pass / fail judgments on the measurement results as needed. The control unit 3 may be incorporated and integrated into the apparatus main body 2. As will be described in detail later, the data acquired by the apparatus main body 2 includes, in addition to image data of the workpiece W, data related to the contact point when a touch probe 80 (described later) comes into contact with the workpiece W, data measured by a non-contact displacement meter 70 (shown in FIG. 3), and the like.

[0021] The display unit 4 displays, for example, various setting screens, image data, measurement results, etc. The display unit 4 is configured, for example, with a liquid crystal display, an organic EL display, etc. In this example, the display unit 4 is shown as being separate from the device main body 2 and the control unit 3, but this is not limiting and the display unit 4 may be incorporated into the device main body 2 or the control unit 3.

[0022] The image measuring device 1 further includes a keyboard 5, a mouse 6, and the like as operation devices for the user. The operation devices are not limited to the keyboard 5 and the mouse 6, but may be touch panel type operation devices, etc. For example, the control unit 3 may be configured as a notebook type personal computer, in which case the keyboard 5, the mouse 6, and the display unit 4 are integrated into the control unit 3.

[0023] The image measuring device 1 further includes a storage unit 7. The storage unit 7 can be configured with, for example, a hard disk drive or a solid state drive, and is a part that stores various data acquired by the device main body 2, user setting information, images, measurement results, pass / fail judgment results, etc. The storage unit 7 may be built into the control unit 3, or may be provided externally to the control unit 3. When the storage unit 7 is provided externally to the control unit 3, it may be, for example, a cloud-type storage connected via a communication line such as the Internet.

[0024] (Configuration of device main body 2) As shown in FIG. 2, the apparatus main body 2 includes a base 20 and a stage 21 that is provided so as to be horizontally movable relative to the base 20. The stage 21 may be capable of being raised and lowered. A mounting table 21a made of a light-transmitting material such as glass is provided near the center of the stage 21, and a workpiece W can be placed on this mounting table 21a. The stage 21 is supported by the base 20 so as to be movable in horizontal directions (the X direction, which is the width direction of the apparatus main body 2, and the Y direction, which is the depth direction of the apparatus main body 2). That is, the apparatus main body 2 includes an XY-direction driving unit 23 (schematically shown in FIGS. 3 and 4) that drives the stage 21. The XY-direction driving unit 23 can move the stage 21 within a predetermined range in the X direction and within a predetermined range in the Y direction. In addition to moving the stage 21 linearly in the X direction or in the Y direction, the stage 21 can also be moved so that the movement trajectory is inclined relative to the X axis or Y axis in a plan view, or so that the stage 21 draws an arbitrary curve.

[0025] The XY direction drive unit 23 has an X direction linear scale 23a for detecting the movement distance in the X direction and a Y direction linear scale 23b for detecting the movement distance in the Y direction. The X direction linear scale 23a makes it possible to detect the left-right position and movement distance of the stage 21. The Y direction linear scale 23b makes it possible to detect the depth direction position and movement distance of the stage 21.

[0026] The XY direction drive unit 23 is controlled by the control unit 3. The control unit 3 controls the XY direction drive unit 23 based on control signals output from the control unit 3, determines the current position of the stage 21 based on detection signals from the X direction linear scale 23a and the Y direction linear scale 23b, and moves the stage 21 to a desired position and also moves the stage 21 so as to trace a desired movement trajectory.

[0027] In the description of this embodiment, the Z direction will be referred to as the up-down direction or height direction, the X direction as the left-right direction, and the Y direction as the front-rear direction, but this is for convenience of description and does not limit the posture during use of the device main body 2. Also, since the user is usually often in front of the device main body 2, the user side of the device main body 2 will be simply referred to as the front, the side opposite the user will be simply referred to as the back, the right side as seen from the user will be simply referred to as the right side, and the left side as seen from the user will be simply referred to as the left side.

[0028] 3 and 4, a transmission illuminator 30 serving as a light projector is provided below the stage 21 of the base 20. As shown in FIG. 4, the transmission illuminator 30 includes a transmission illumination light source 31, such as a light-emitting diode, a slit 32 through which light emitted from the transmission illumination light source 31 passes, a mirror 33 for directing the light that has passed through the slit 32 upward, and a lens 34 onto which the light directed upward by the mirror 33 is incident. The lens 34 is a lens that can convert the incident light into parallel light and emit the parallel light. The light emitted from the lens 34 is directed toward the mounting table 21a of the stage 21, passes through the mounting table 21a, and is irradiated from below onto the workpiece W placed on the mounting table 21a.

[0029] 2, a measurement start button 2a is provided on the front side of the base 20 of the device main body 2. The measurement start button 2a is a button that the user operates when starting measurement of the workpiece W. When measurement is to be performed, the measurement operation is executed by simply pressing the measurement start button 2a.

[0030] The device main body 2 includes a support unit 22 and a measurement unit 24. As shown in Figures 3 and 4, the support unit 22 is connected to the rear portion of the base 20 and extends upward from the rear portion of the base 20. The measurement unit 24 is supported by an upper portion of the support unit 22. The measurement unit 24 is provided with a coaxial epi-illumination unit 40, a ring illumination unit 45, an imaging unit 50, a non-contact displacement meter 70, a lens unit 81 of a touch probe 80, and the like.

[0031] The measurement unit 24 is configured separately from the support unit 22 and is movable in the Z direction relative to the support unit 22. That is, the device body 2 is equipped with a Z-direction drive unit 25 that drives the measurement unit 24, and the Z-direction drive unit 25 allows the measurement unit 24 to move linearly from the uppermost position to the lowermost position. The imaging axis of the imaging unit 50 coincides with the Z axis, and therefore the imaging axis extends in the Z direction. The measurement unit 24 is an example of a movable unit that moves along the imaging axis of the imaging unit 50.

[0032] The Z-direction driver 25 has a Z-direction linear scale 25a for detecting the distance traveled in the Z direction, and the Z-direction linear scale 25a makes it possible to detect the height of the measurement execution unit 24, the distance traveled in the height direction, etc. The Z-direction driver 25 is controlled by a control unit 3d included in the control unit 3. The control unit 3d controls the Z-direction driver 25 using a control signal, determines the current position of the measurement execution unit 24 based on the detection signal from the Z-direction linear scale 25a, and moves the measurement execution unit 24 to the desired position. The movement speed of the measurement execution unit 24 can be changed in multiple steps or continuously.

[0033] The coaxial epi-illumination 40 is a light projection unit, and as shown in FIG. 4, includes a coaxial epi-illumination light source 41, which may be a light-emitting diode or the like, a lens 42 onto which light emitted from the coaxial epi-illumination light source 41 is incident, and a direction changing member 43 that directs the light emitted from the lens 42 downward. The direction changing member 43 is made of a light-transmitting member that can transmit light in both the vertical and horizontal directions. The light emitted from the direction changing member 43 is detection light. The detection light emitted from the direction changing member 43 is directed toward the mounting table 21a of the stage 21, and is irradiated from above onto the workpiece W placed on the mounting table 21a, i.e., the workpiece W on the stage 21.

[0034] The imaging unit 50 has a light receiving lens 51, a beam splitter 52, a high-magnification side imaging lens 53, a low-magnification side imaging lens 54, a high-magnification side imaging element 55, and a low-magnification side imaging element 56, which together form a first imaging unit. The imaging unit 50 is supported by a support part 22 above the stage 21 in an orientation in which the imaging direction is the normal direction (Z direction) of the stage 21.

[0035] 5, the light-receiving lens 51 of the imaging unit 50 is disposed on the underside of the measurement execution unit 24, and is positioned so that its light-receiving surface faces the upper surface of the mounting table 21a of the stage 21. Therefore, the light-receiving lens 51 can receive the detection light irradiated from the coaxial epi-illumination 40 and reflected by the surface of the workpiece W, and can also receive the light irradiated from the transmitted illumination 30.

[0036] The optical axis of the light-receiving lens 51 coincides with the Z direction. In this example, the direction conversion member 43 of the coaxial epi-illumination illuminator 40 is located directly above the light-receiving lens 51, so the detection light emitted from the coaxial epi-illumination illuminator 40 passes through the light-receiving lens 51 and is irradiated onto the workpiece W on the stage 21.

[0037] The beam splitter 52 is disposed above the direction-changing member 43 and is composed of a prism that splits the light emitted upward from the light-receiving lens 51 into two directions. The beam splitter 52 can be, for example, a cube-type or plate-type beam splitter. Compared to a plate-type beam splitter, a cube-type beam splitter is preferable because the light passing through the beam splitter is not refracted, so the optical axis does not shift and alignment of the splitting angle is easy. In this example, light entering the beam splitter 52 via the light-receiving lens 51 is split upward and backward. For this reason, the high-magnification imaging lens 53 is disposed above the beam splitter 52, while the low-magnification imaging lens 54 is disposed behind the beam splitter 52. The high-magnification imaging element 55 is disposed above the high-magnification imaging lens 53, and the light entering the high-magnification imaging lens 53 forms an image on the light-receiving surface of the high-magnification imaging element 55. In addition, the low-magnification side image pickup element 56 is disposed behind the low-magnification side image formation lens 54, and light incident on the low-magnification side image formation lens 54 is imaged on the light receiving surface of the low-magnification side image pickup element 56.

[0038] The high-magnification side imaging element 55 and the low-magnification side imaging element 56 are configured with a CCD (Charge-Coupled Device) image sensor, a CMOS (Complementary MOS) image sensor, or the like. The workpiece image acquired by the low-magnification side imaging element 56 is a low-magnification image, and the workpiece image acquired by the high-magnification side imaging element 55 is a high-magnification image with a higher magnification than the low-magnification image. In this example, in order to improve measurement accuracy, the high-magnification side imaging element 55 and the low-magnification side imaging element 56 are configured with single-channel imaging elements so as to acquire high-resolution workpiece images. Therefore, the workpiece images output from the high-magnification side imaging element 55 and the low-magnification side imaging element 56 are monochrome images (grayscale images).

[0039] The focal position of the imaging unit 50 is adjusted by the Z-direction driver 25. That is, the control unit 3d can move the measurement unit 24 in the Z direction by controlling the Z-direction driver 25. Since the Z direction coincides with the imaging axis direction of the imaging unit 50, the imaging unit 50 can be moved along the imaging axis. In other words, the Z-direction driver 25 is a focus adjustment mechanism that adjusts the focal position of the imaging unit 50, and the focus of the imaging unit 50 can be adjusted by moving the measurement unit 24 in a direction along the imaging axis. When adjusting the focus, in addition to autofocus using algorithms such as a conventional contrast method or phase difference method, manual focus, in which the user performs adjustment by performing a predetermined operation, is also possible.

[0040] The bifurcated optical system configuration using the light receiving lens 51 and beam splitter 52 described above allows high-magnification and low-magnification images to be acquired simultaneously without mechanically switching the optical system. Note that the bifurcated optical system configuration using the beam splitter 52 may be omitted, and high-magnification and low-magnification images may be acquired by mechanically switching between the high-magnification lens and the low-magnification lens.

[0041] The ring illumination 45 is a light projecting unit that irradiates the workpiece W on the stage 21 with monochromatic light (white light) or detection light of a plurality of different wavelengths. The detection light of a plurality of different wavelengths includes, for example, red light, green light, blue light, etc. The ring illumination 45 has a circular shape that surrounds the outer periphery of the light-receiving lens 51, and is disposed below the light-receiving lens 51 on the same axis as the light-receiving lens 51.

[0042] 6, the ring illumination 45 includes a red light source 45a that emits red light, a green light source 45b that emits green light, and a blue light source 45c that emits blue light. The red light source 45a, the green light source 45b, and the blue light source 45c are each composed of a light-emitting diode or the like and can be turned on and off individually. That is, by turning on only the red light source 45a, the workpiece W is illuminated with red light, by turning on only the green light source 45b, the workpiece W is illuminated with green light, by turning on only the blue light source 45c, the workpiece W is illuminated with green light, and by turning on all of the red light source 45a, the green light source 45b, and the blue light source 45c, the workpiece W is illuminated with white light.

[0043] The ring illumination 45 is equipped with a Z-direction illumination drive unit 45d, which allows the ring illumination 45 to move linearly from an upper end position to a lower end position. By moving the ring illumination 45 according to the height of the workpiece W, it becomes possible to irradiate the detection light from a position close to the workpiece W. The Z-direction illumination drive unit 45d has a Z-direction linear scale 45e for detecting the movement distance in the Z direction, which makes it possible to detect the height of the ring illumination 45, the movement distance in the height direction, etc. In this embodiment, the ring illumination 45 is arranged outside the housing of the measurement execution unit 45, but the present invention is not limited to this and the ring illumination 45 may be arranged inside the housing of the measurement execution unit 45.

[0044] 3, the mirror 33 that guides the transmitted illumination light 30 to the stage 21, the ring illumination light 45, the direction changing member 43 that guides the coaxial epi-illumination light 40 to the stage 21, and the imaging unit 50 (for example, high-magnification image sensor 55) are arranged in a substantially straight line in the vertical direction. The ring illumination light 45, the direction changing member 43, and the imaging unit 50 are fixed to a housing of the measurement unit 24 that is movable up and down, and are movable together in the Z direction. In addition, in this embodiment, the housing 81 of the touch probe 80, which will be described later, is also fixed to the housing of the measurement unit 24, and is also movable together in the Z direction.

[0045] The measurement execution unit 24 has a first stage camera 46, a second stage camera 47, and a front camera 48. Because the measurement execution unit 24 is provided in the upper portion of the support unit 22, the first stage camera 46, the second stage camera 47, and the front camera 48 are also provided in the upper portion of the support unit 22. The first stage camera 46, the second stage camera 47, and the front camera 48 each have an image sensor capable of acquiring color images. Furthermore, the number of pixels of the first stage camera 46, the second stage camera 47, and the front camera 48 is smaller than that of the high-magnification side image sensor 55 and the low-magnification side image sensor 56, but this is not a limitation, and they may have approximately the same number of pixels.

[0046] As shown in Fig. 4, first stage camera 46 and second stage camera 47 are disposed in front of light receiving lens 51 and are spaced apart from each other in the left-right direction. The imaging direction (optical axis direction) of first stage camera 46 and second stage camera 47 is the same as the imaging direction of imaging unit 50. The imaging fields of first stage camera 46 and second stage camera 47 are located in front of the imaging field of imaging unit 50, and are able to image the front portion of stage 21. Note that first stage camera 46 or second stage camera 47 generates an overhead image (planar image) by capturing an overhead image of the entire stage 21 from directly above, and may also be called an overhead image generation unit.

[0047] The front camera 48 is a second imaging unit that captures an image of the workpiece W above the stage 21 in a position where the imaging direction is different from the normal direction of the stage 21 to generate an overhead image, and can also be referred to as the overhead image generating unit. The front camera 48 is disposed in front of the light receiving lens 51 and is positioned forward of the first stage camera 46 and the second stage camera 47 in the front-to-back direction. Therefore, the front camera 48 can be said to be the camera disposed closest to the user. The imaging field of the front camera 48 is set wider than the imaging field of the high-magnification side imaging element 55 and the low-magnification side imaging element 56, and includes the imaging field of the high-magnification side imaging element 55 and the low-magnification side imaging element 56, and can also capture images outside the imaging field of the high-magnification side imaging element 55 and the low-magnification side imaging element 56. In this example, the front camera 48 can capture an image of the entire top surface of the stage 21. The front camera 48 is also configured to capture images in real time and is a camera that can acquire live view images.

[0048] The imaging direction (optical axis direction) of the front camera 48 is set to a direction from diagonally above in front of the stage 21 toward the top surface of the stage 21, that is, from the front to the back when viewed from the user. This is to ensure that the line of sight when the user views the stage 21 during measurement roughly matches the imaging direction of the front camera 48. As a result, the overhead image generated by the front camera 48 corresponds to what the user can see when looking down on the workpiece W in a natural measurement posture.

[0049] (Configuration of non-contact displacement meter 70) The non-contact displacement meter 70 is a non-contact measurement unit that measures the height of the workpiece W on the stage 21 in a non-contact manner by emitting measurement light along the normal direction of the stage 21 and receiving reflected light from the workpiece W on the stage 21. The non-contact displacement meter 70 is a laser coaxial displacement meter, more specifically a white light confocal displacement meter, and as shown in FIG. 3, it includes a lens unit 71, a light-emitting and receiving unit 72, and an optical fiber unit 73 that connects the two units 71 and 72. The light-emitting and receiving unit 72 is built into the base 20, and includes a laser light source 72a, a light-source optical member 72b, a phosphor 72c, and a light-receiving element 72d.

[0050] The laser light source 72a emits light of a single wavelength, preferably blue or ultraviolet light with a wavelength of 450 nm or less. In particular, if the laser light source 72a emits blue light, it can project onto the workpiece W light that is a mixture of wavelength-converted light that is used to excite the phosphor 72c and blue light that is not used to excite the phosphor 72c.

[0051] The phosphor 72c is excited by light from the laser light source 72a and converts the light to a different wavelength and emits the light. The phosphor 72c is made up of one or more types of phosphors 72c, and may be configured to be excited by blue light and convert the light to yellow light and emit light, or two types of phosphors 72c may be configured to be excited by blue light and convert the light to green and to be excited by blue light and convert the light to red and emit light.

[0052] The optical fiber portion 73 is composed of one or more optical fibers. For ease of handling, a ferrule 73a may be used at the end of the optical fiber. The core diameter of the output end, which is the end of the optical fiber portion 73 on the lens unit 71 side, affects the spot diameter formed on the workpiece W, so it can be set to a diameter of 200 μm or less, and may also be set to a diameter of 50 μm or less.

[0053] The phosphor 72c is fixed to the incident end side of the optical fiber portion 73. The phosphor 72c may be fixed in an optically transparent medium such as resin or glass that transmits the light from the laser light source 72a and the light emitted by the phosphor 72c, and the optically transparent medium may be fixed to the incident end of the optical fiber portion 73. In this case, in order to efficiently allow the light from the laser light source 72a and the light from the phosphor 72c to enter the optical fiber portion 73, the refractive index of the optically transparent medium is set to be equal to or lower than the refractive index of the core on the incident end side of the optical fiber portion 73.

[0054] The light receiving element 72d is composed of an imaging element such as a multi-segment PD (photodiode) or a CCD or CMOS, and selectively receives light from the workpiece W according to wavelength via a spectroscope 72e composed of a diffraction grating, a prism, or a color-selective optical filter. The light receiving element 72d may receive light from the workpiece W via the optical fiber section 73, or may receive light via another optical path.

[0055] The lens unit 71 is attached to the measurement execution section 24 and is therefore movable in the Z direction together with the imaging section 50. The lens unit 71 is a member for focusing light emitted from the emission end of the optical fiber section 73 toward the workpiece W, and includes an upper lens 71a and a lower lens 71b. The lens unit 71 is disposed to the right of the imaging section 50, and its optical axis is in the Z direction.

[0056] When the lens unit 71 is configured to be confocal with the output end of the optical fiber section 73, the light from the workpiece W is separated according to wavelength by a spectroscope 72e configured with a diffraction grating, a prism, etc., and the wavelength-brightness distribution of the light from the workpiece W is detected based on the light receiving position of the light receiving element 72d. A signal relating to the light receiving position and amount of light received by the light receiving element 72d is transmitted to a displacement measuring section 3c provided in the control unit 3.

[0057] For example, when a chromatic aberration lens is used as the lens unit 71, the displacement measuring unit 3c shown in Fig. 6 evaluates that the workpiece W is located at a closer distance when light with a shorter wavelength is detected, and that the workpiece W is located at a farther distance when light with a longer wavelength is detected. Also, when a diffractive lens is used as the lens unit 71, the displacement measuring unit 3c measures the displacement of the workpiece W by evaluating that the workpiece W is located at a farther distance when light with a shorter wavelength is detected, and that the workpiece W is located at a closer distance when light with a longer wavelength is detected.

[0058] 3, the focal length of the non-contact displacement meter 70 is set longer than the focal length of the imaging unit 50. The focal height of the non-contact displacement meter 70 is set to be approximately the same as the focal height of the imaging unit 50. That is, the mounting height of the lens unit 71 of the non-contact displacement meter 70 relative to the measurement execution unit 24 and the mounting height of the imaging unit 50 relative to the measurement execution unit 24 can be set arbitrarily, but in this example, the height of the lens unit 71 and the height of the imaging unit 50 are set so that the focal height of the non-contact displacement meter 70 and the focal height of the imaging unit 50 are approximately the same. For example, the lower lens 71b of the lens unit 71 is disposed above the light-receiving lens 51 of the imaging unit 50.

[0059] In this example, the non-contact displacement meter 70 can be moved by the Z-direction drive unit 25, so by matching the focal length of the imaging unit 50 with the focal length of the non-contact displacement meter 70, it is possible to perform height measurement using the non-contact displacement meter 70 simply by moving the stage 21 horizontally so as to focus the non-contact displacement meter 70 on the measurement target position which is at the focal length of the imaging unit 50.

[0060] (Touch probe configuration) The touch probe 80 shown in FIG. 3 is a component that outputs a contact signal when it comes into contact with a workpiece W on the stage 21. In this example, the touch probe 80 is provided in the measurement execution unit 24, and therefore the Z-direction driver 25 can move the touch probe 80 relative to the stage 21 in the Z direction. The stage 21 can also be moved relative to the touch probe 80 in the X and Y directions by the XY-direction driver 23. In this manner, the Z-direction driver 25 and the XY-direction driver 23 move at least one of the stage 21 and the touch probe 80 relative to the other, thereby allowing the touch probe 80 to come into contact with the workpiece W placed on the stage 21. The stage 21 may be moved in the Z direction, or the touch probe 80 may be moved in the X and Y directions. The X-axis is an axis that is perpendicular to the Z-axis and coincides with the left-right direction of the apparatus main body 2. The Y-axis is an axis that is perpendicular to the Z-axis and coincides with the direction perpendicular to the X-axis (the front-rear direction of the apparatus main body 2).

[0061] The contact signal output from the touch probe 80 is transmitted to the coordinate measuring section 3b of the control unit 3 shown in Fig. 6. Upon receiving the contact signal output by the Z-direction driving section 25 and the XY-direction driving section 23 when the touch probe 80 comes into contact with the workpiece W, the coordinate measuring section 3b measures the three-dimensional coordinates of the contact point where the touch probe 80 comes into contact with the workpiece W based on the contact signal.

[0062] For example, the X-direction position and Y-direction position of the stage 21 when a contact signal of the touch probe 80 is output can be obtained by the X-direction linear scale 23a and the Y-direction linear scale 23b, respectively. Also, the Z-direction position of the touch probe 80 when a contact signal of the touch probe 80 is output can be obtained by the Z-direction linear scale 25a. Also, by setting the relative positional relationship between the touch probe 80 and the workpiece W in advance and performing calibration of the imaging unit 50, etc., it is possible to measure the three-dimensional coordinates of the contact point based on the detection results of the linear scales 23a, 23b, and 25a.

[0063] 7, the touch probe 80 includes a housing 81, a probe shaft 82, a stylus 83, a fulcrum forming elastic member (first elastic member) 84, an origin returning elastic member (second elastic member) 85, and a displacement detection mechanism 86. The housing 81 has a cylindrical shape extending in the Z direction, and as shown in FIG. 5, is fixed to the measurement execution unit 24 and disposed to the left of the imaging unit 50. Therefore, the imaging unit 50 is interposed between the touch probe 80 and the lens unit 71 of the non-contact displacement meter 70.

[0064] As shown in Fig. 7, the probe shaft 82 is a rod-shaped member provided inside the housing 81 and extends in the Z direction. An upper cylindrical member 82a having a diameter larger than the outer diameter of the probe shaft 82 is fixed to the lower end of the probe shaft 82. The stylus 83 is also formed of a rod-shaped member extending in the Z direction like the probe shaft 82, but is thinner than the probe shaft 82. A spherical contact portion 83b that comes into contact with the workpiece W is provided at the lower end of the stylus 83.

[0065] The upper end of the stylus 83 is detachably attached to the underside of a cylindrical member 82a of the probe shaft 82. That is, a lower cylindrical member 83a having a diameter larger than the outer diameter of the stylus 83 is fixed to the upper end of the stylus 83. The upper cylindrical member 82a and the lower cylindrical member 83a have approximately the same diameter, but the dimension in the vertical direction of the lower cylindrical member 83a is set to be longer. Incidentally, since the probe shaft 82 is integrated with the housing 81, it can also be said that the stylus 83 is detachably attached to the housing 81.

[0066] The structure for attaching and detaching the stylus 83 to the probe shaft 82 is not particularly limited, but a kinematic mount or the like can be used, for example. That is, permanent magnets (not shown) having mutually attracting polarities are fixed to the lower surface of the upper cylindrical member 82a and the upper surface of the lower cylindrical member 83a, respectively. Three steel balls 83c, for example, are fixed at equal intervals in the circumferential direction around one of the magnets on the lower surface of the upper cylindrical member 82a or the upper surface of the lower cylindrical member 83a, and fitting grooves (not shown) into which the steel balls 83c fit are formed around the magnet on the other surface so as to correspond to the positions of the steel balls 83c. As a result, when the stylus 83 is brought closer to the probe shaft 82 from below, the attractive force of the magnets fixed to the upper cylindrical member 82a and the lower cylindrical member 83a causes the stylus 83 to be held in an attracted state to the probe shaft 82. Alternatively, when the probe shaft 82 is brought closer to the stylus 83 from above, the attractive force of the magnets fixed to the upper cylindrical member 82a and the lower cylindrical member 83a causes the stylus 83 to be held in a state of being attracted to the probe shaft 82. At this time, the steel ball 83c fits into the fitting groove, and the stylus 83 is positioned coaxially with the probe shaft 82.

[0067] When removing the stylus 83 from the probe shaft 82, the stylus 83 is moved downward against the magnetic force while the probe shaft 82 is fixed, or the probe shaft 82 is moved upward against the magnetic force while the stylus 83 is fixed. This separates the lower cylindrical member 83a from the upper cylindrical member 82a, and the stylus 83 is removed.

[0068] The fulcrum-forming elastic member 84 is a member connected to the housing 81 and the probe shaft 82 to form a deflection fulcrum for the probe shaft 82, and is formed, for example, by a flat spring. Specifically, the fulcrum-forming elastic member 84 is formed by a leaf spring that extends along the radial extension of the probe shaft 82 and has its radially outer end connected to the inner surface of the housing 81. An example of the shape of the fulcrum-forming elastic member 84 is shown in FIG. 8 , where the outer shape of the fulcrum-forming elastic member 84 is a circle formed to fit the inner surface of the housing 81. An insertion hole 84a through which the probe shaft 82 can be inserted is formed in the center of the fulcrum-forming elastic member 84, and the probe shaft 82 is fixed in a state where it is inserted through the insertion hole 84a. The fulcrum-forming elastic member 84 is integrally formed with an outer portion 84b, an inner portion 84c in which the insertion hole 84a is formed, and three connecting portions 84d that connect the outer portion 84b and the inner portion 84c.

[0069] The fulcrum-forming elastic member 84 can be made of an elastic material that has shape recovery in the axial direction. The material and shape of the fulcrum-forming elastic member 84 are set so that the inner portion 84c remains positioned at the axial center and radial displacement is suppressed. This allows the deflection fulcrum of the probe shaft 82 to be maintained by the fulcrum-forming elastic member 84. When the stylus 83 contacts the workpiece W, the fulcrum-forming elastic member 84 deforms with a force small enough to not affect the contact resistance. To enable the probe shaft 82 to be displaced in the Z direction with a small force, the fulcrum-forming elastic member 84 is designed so that the inner portion 84c can be displaced in the Z direction relative to the outer portion 84b with a small force.

[0070] 7, a support portion 81a for supporting from below an outer portion 84b (shown in FIG. 8) of the fulcrum-forming elastic member 84 is provided inside the housing 81. Since the outer portion 84b is supported by the support portion 81a, the probe shaft 82 is held at a predetermined height and stabilized, and is less likely to vibrate, improving measurement accuracy.

[0071] The origin-returning elastic member 85 is connected to the housing 81 and the probe shaft 82 at a position axially distant from the fulcrum-forming elastic member 84 of the probe shaft 82, and serves to return the probe shaft 82 to the origin. In this manner, the fulcrum-forming elastic member 84 for forming a deflection fulcrum and the origin-returning elastic member 85 for returning the probe shaft 82 to the origin are provided separately, and the elastic members 84, 85 are designed to fulfill different functions. That is, the fulcrum-forming elastic member 84 is set to have a stronger force for suppressing radial displacement of the probe shaft 82 than the origin-returning elastic member 85, and the origin-returning elastic member 85 is set to have a stronger biasing force for biasing the probe shaft 82 toward the origin than the fulcrum-forming elastic member 84.

[0072] The origin return elastic member 85 is provided closer to the tip (lower) of the probe shaft 82 than the fulcrum forming elastic member 84, and as shown in Fig. 9, it extends radially from the probe shaft 82 and along the radial extension of the probe shaft 82, and is composed of three or more tension springs 85a, 85b, 85c whose outer ends are connected to the housing 81, and is set so that the spring forces of the three or more tension springs 85a, 85b, 85c are balanced. In this example, the origin return elastic member 85 is composed of three tension springs 85a, 85b, 85c, but the number of tension springs 85a, 85b, 85c is not limited to this.

[0073] The inner end of each of the tension springs 85a, 85b, and 85c is fixed to the outer surface of the probe shaft 82, and the three fixed portions are arranged at equal intervals (120° intervals) in the circumferential direction. Each of the tension springs 85a, 85b, and 85c is oriented so that its axis is perpendicular to the axis of the probe shaft 82, and extensions of the axes of each of the tension springs 85a, 85b, and 85c intersect on the axis of the probe shaft 82. The tension springs 85a, 85b, and 85c have the same spring constant.

[0074] Assume that the probe shaft 82 is displaced in one of the three tension springs 85a, 85b, and 85c. If tension spring 85a is balanced at a position where it is compressed by ΔA, the remaining tension springs 85b and 85c are displaced by A / 2 according to vector division. Half of the force acts in the direction of tension spring 85a, and ultimately, half of the force of tension spring 85a is added together, resulting in a combined force of 1.5 × ΔA acting to achieve balance. Because the three tension springs 85a, 85b, and 85c have the same spring constant, the spring constant is the only design parameter: spring constant × ΔA × 1.5. In other words, if the same spring constant is set for tension springs 85a, 85b, and 85c, a low-pressure contact touch probe 80 can be achieved, even if the lengths at which balance is maintained vary.

[0075] Furthermore, because the touch probe 80 has low contact pressure, applying an excessive stroke to the probe shaft 82 may exceed its elastic limit or cause deformation of the probe shaft 82. For this reason, it may be desirable to provide a protective limit mechanism and adopt a configuration that can tolerate even stronger external forces. For example, if the contact portion 83b is pressed strongly in the X direction, if the limit mechanism is located above, the probe shaft 82 may be subjected to a bending force, which may induce deformation of the probe shaft 82. In other words, if the origin return elastic member 85 is located above the fulcrum-forming elastic member 84, the probe shaft 82 may be subjected to a bending force when subjected to a large external force in the X direction as described above. In this example, the origin return elastic member 85 is located below the fulcrum-forming elastic member 84, thereby making the probe shaft 82 less susceptible to bending forces. Note that the above-mentioned problem does not apply in all cases, and the origin return elastic member 85 may also be located above the fulcrum-forming elastic member 84.

[0076] Furthermore, for example, since the probe shaft 82 is configured to be pulled radially by three tension springs 85a, 85b, and 85c having the same spring constant, a displacement reduced by the ratio H1 / H2 (shown in FIG. 7) of the amount of movement of contact portion 83b acts on tension springs 85a, 85b, and 85c based on the principle of leverage relative to the origin position balanced with a predetermined elongation, and the difference from this balance can be calculated using only the displacement and spring constant. For example, if contact with workpiece W is to be detected with an extremely low contact pressure of about 2g, the spring constant can be derived by reverse calculation, allowing for the construction of a very simple relationship. From this relationship, even if tension springs 85a, 85b, and 85c are configured with springs of relatively high force, the resistance force at contact portion 83b will not increase too much, and a touch probe 80 with low contact pressure can be obtained.

[0077] 7, the displacement detection mechanisms 86A, 86B, and 86C are magnetic sensors that detect displacements of the probe shaft 82 in three-dimensional directions in a non-contact manner, and are provided on the base end side (upper side) of the probe shaft 82 relative to the fulcrum-forming elastic member 84. Specifically, the displacement detection mechanisms 86A, 86B, and 86C include a Z-direction displacement detection mechanism 86A (first displacement detection mechanism) that detects displacement in the Z-direction (first direction) along the axial direction of the probe shaft 82, an X-direction displacement detection mechanism 86B (second displacement detection mechanism) that detects displacement in the X-direction (second direction) along the radial direction of the probe shaft 82, and a Y-direction displacement detection mechanism 86C (third displacement detection mechanism) that detects displacement in the Y-direction (third direction) along the radial direction of the probe shaft 82 and perpendicular to the Z-direction.

[0078] The Z-direction displacement detection mechanism 86A includes a Z-direction detection magnet 86a arranged so that its north and south poles are aligned in the Z direction, and a Z-direction magnetic sensor 86b. The Z-direction detection magnet 86a is fixed to the probe shaft 82, while the Z-direction magnetic sensor 86b is fixed to the housing 81. The Z-direction magnetic sensor 86b is arranged to face the boundary between the north and south poles of the Z-direction detection magnet 86a. Therefore, even a slight displacement of the probe shaft 82 in the Z direction changes the magnetic field detected by the Z-direction magnetic sensor 86b, thereby enabling contactless detection of the Z-direction displacement of the probe shaft 82.

[0079] A magnet fixing member 82b is provided at the upper end of the probe shaft 82. The X-direction displacement detection mechanism 86B includes an X-direction detection magnet 86c arranged so that its north and south poles are aligned in the X direction, and an X-direction magnetic sensor 86d. The X-direction detection magnet 86c is fixed to the upper surface of the magnet fixing member 82b, while the X-direction magnetic sensor 86d is fixed to the housing 81. The X-direction magnetic sensor 86d is disposed to face the boundary between the north and south poles of the X-direction detection magnet 86c. Therefore, when the probe shaft 82 oscillates and displaces even slightly in the X direction around the deflection fulcrum, the magnetic field detected by the X-direction magnetic sensor 86d changes, thereby enabling contactless detection of the X-direction displacement of the probe shaft 82.

[0080] The Y-direction displacement detection mechanism 86C includes a Y-direction detection magnet 86e arranged so that its north and south poles are aligned in the Y direction, and a Y-direction magnetic sensor 86f. The Y-direction detection magnet 86e is fixed to the upper surface of the magnet fixing member 82b at a position away from the X-direction detection magnet 86c, while the Y-direction magnetic sensor 86f is fixed to the housing 81. The Y-direction magnetic sensor 86f is arranged to face the boundary between the north and south poles of the Y-direction detection magnet 86e. Therefore, when the probe shaft 82 oscillates and displaces even slightly in the Y direction around the deflection fulcrum, the magnetic field detected by the Y-direction magnetic sensor 86f changes, thereby enabling contactless detection of the Y-direction displacement of the probe shaft 82.

[0081] The displacement detection mechanism 86 may be a sensor other than a magnetic sensor, and may be, for example, an optical or capacitance type detection sensor.

[0082] The tension springs 85a, 85b, and 85c are coated with damping grease that generates a damping force. The damping grease is a highly viscous, non-volatile paste that is applied to the tension springs 85a, 85b, and 85c so that it fills the spaces between the wires of the tension springs 85a, 85b, and 85c. This allows the tension springs 85a, 85b, and 85c to apply damping force multiple times in a short period of time when they expand and contract, making it easier to achieve the desired damping and eliminating the need to apply excessive damping, which can cause noise.

[0083] When damping the tension springs 85a, 85b, and 85c, it is possible to use damping grease or the like at a distance where the damping effect can be increased based on the principle of leverage. For example, damping grease may be filled between the Z-direction detection magnet 86a and the Z-direction magnetic sensor 86b, between the X-direction detection magnet 86c and the X-direction magnetic sensor 86d, and between the Y-direction detection magnet 86e and the Y-direction magnetic sensor 86f. Furthermore, other damping members may be used to damp the tension springs 85a, 85b, and 85c.

[0084] 10 is a diagram showing another example of the touch probe 80. In this example, the orientation of the X-direction magnetic sensor 86d of the X-direction displacement detection mechanism 86B and the orientation of the Y-direction magnetic sensor 86f of the Y-direction displacement detection mechanism 86C are different from those in the example described above. Specifically, the X-direction magnetic sensor 86d and the X-direction detection magnet 86c are arranged to face each other in the horizontal direction, and the Y-direction magnetic sensor 86f and the Y-direction detection magnet 86e are arranged to face each other in the horizontal direction.

[0085] (Stylus changer mechanism) Styluses 83 come in a variety of shapes, such as cross-shaped, L-shaped, and T-shaped, as well as diameters and sizes of contact portions 83b at the tips. These styluses are selected based on the workpiece W and the measurement application. As shown in FIGS. 1 and 2, the support 22 of the device body 2 is provided with a changer mechanism (exchange unit) 100 that holds different styli 83A, 83B, and 83C and automatically replaces the stylus with the desired one at a predetermined timing. In this example, the touch probe 80 is provided on the left side of the measurement unit 24, and the changer mechanism 100 is provided on the left side of the support 22 accordingly. If the touch probe 80 were provided on the right side of the measurement unit 24, the changer mechanism 100 would simply be provided on the right side of the support 22.

[0086] 11 is a perspective view of a stylus changer mechanism 100. The changer mechanism 100 includes a stylus holder 101 that holds one or more styli, an arm 102 that supports the stylus holder 101, a changer rotation drive unit (rotating unit) 103 that rotates the arm 102, and a changer feed drive unit (slider unit) 104 that moves the stylus holder 101 along the arm 102.

[0087] As shown in FIG. 12, the stylus holder 101 has first to third cutout portions 101a, 101b, and 101c that hold different types of styluses 83A, 83B, and 83C. Each of the cutout portions 101a, 101b, and 101c is open in both the vertical and horizontal directions, and the opening direction is the same for all of the cutout portions 101a, 101b, and 101c. Note that in FIG. 12, the upper portion of the third cutout portion 101c is shown removed for ease of explanation of the internal structure, but the third cutout portion 101c has the same shape as the first cutout portion 101a and the second cutout portion 101b. Note that the number of cutout portions is not limited to three and can be set to any number.

[0088] A holding claw 101d for holding a stylus is provided at the vertical center of each of the notches 101a, 101b, and 101c. The holding claw 101d is made of an elastic material such as resin and has a shape that opens in the same direction as the horizontal opening of each of the notches 101a, 101b, and 101c. Both ends of the holding claw 101d protrude from the inner surface of each of the notches 101a, 101b, and 101c, and both ends of the holding claw 101d are adapted to engage with a groove 83d formed on the outer peripheral surface of the lower cylindrical member 83a of the stylus 83. The vertical dimension of the groove 83d is set longer than the vertical dimension of the holding claw 101d. This difference in dimension allows the stylus held by the holding claw 101d to move up and down relative to the holding claw 101d.

[0089] The distance between both ends of the holding claws 101d is narrower than the outer diameter of the portion of the lower cylindrical member 83a where the grooves 83d are formed. When holding the lower cylindrical member 83a, the portions of the lower cylindrical member 83a where the grooves 83d are formed are pressed against both ends of the holding claws 101d from the open side of the holding claws 101d, causing the holding claws 101d to elastically deform and widen the distance between the ends. This allows the portions of the lower cylindrical member 83a where the grooves 83d are formed to enter the inside of the holding claws 101d from between both ends of the holding claws 101d and engage with the holding claws 101d. When removing the lower cylindrical member 83a held by the holding claws 101d, the lower cylindrical member 83a is moved relatively in the opening direction of the holding claws 101d, causing the holding claws 101d to elastically deform and widen the distance between the ends, causing the lower cylindrical member 83a to release from the open side of the holding claws 101d.

[0090] The arm unit 102 shown in FIG. 11 is a member for moving the styluses 83A, 83B, and 83C (reference numerals 83B and 83C are shown in FIG. 2) held by the stylus holder 101 between an attachable position where the styluses can be attached to the housing 81 and a retracted position where the styluses are retracted from the attachable position. The attachable position can also be called a stylus attachment preparation position, and the retracted position can also be called a stylus storage position. Specifically, the arm unit 102 is formed of a member extending horizontally, and its base end is attached to the support unit 22 via a changer rotation drive unit 103. The changer rotation drive unit 103 is formed of an electric motor having a rotation shaft 103a extending in the Z direction. The rotation shaft 103a is parallel to the imaging axis of the imaging unit 50, and the base end of the arm unit 102 is connected to the lower end of the rotation shaft 103a.

[0091] As shown by the dashed line in Fig. 2, the changer rotation drive unit 103 is disposed above the stage 21. Fig. 2 shows a state in which the stylus 83A, 83B, and 83C held by the stylus holder 101 have been moved to a retracted position. The stylus holder 101 and stylus 83A, 83B, and 83C in the retracted position are arranged so as not to get in the way when setting up or executing measurement, specifically so that the stylus holder 101 and stylus 83A, 83B, and 83C do not enter the movable range of the measurement execution unit 24 or the imaging field of view of the imaging unit 50.

[0092] The support part 22 is provided with a canopy part 22A that covers at least a portion of the upper part of the stylus holding part 101 when it is in the retracted position. The canopy part 22A is formed to protrude leftward from the left wall part of the support part 22, allowing the stylus holding part 101 to be positioned directly below the canopy part 22A. This makes it possible to prevent surrounding objects and the like from coming into contact with the stylus holding part 101 or the styluses 83A, 83B, 83C held by the stylus holding part 101. The canopy part 22A may be formed to cover the entire upper part of the stylus holding part 101.

[0093] As shown in Figure 11, the arm unit 102 is provided with a changer feed drive unit 104. The changer feed drive unit 104 includes a feed electric motor 104a, a threaded rod 104b that is driven to rotate by the feed electric motor 104a, and a screw member 104c that screws onto the threaded rod 104b. The feed electric motor 104a is fixed to the base end of the arm unit 102, with its center line of rotation oriented in the longitudinal direction of the arm unit 102. The screw rod 104b is disposed parallel to the arm unit 102 and is supported rotatably relative to the arm unit 102. The stylus holder 101 is fixed to the screw member 104c.

[0094] The arm 102 is provided with a guide rail 102a that guides the stylus holder 101 in the longitudinal direction of the arm 102. The stylus holder 101 is engaged with the guide rail 102a and is unable to rotate, so that it can move only in the longitudinal direction of the arm 102. In other words, the styluses 83A, 83B, and 83C held by the stylus holder 101 can be moved in a direction perpendicular to the imaging axis.

[0095] When the threaded rod 104b is rotated by the feed electric motor 104a, the stylus holder 101 can be moved to the tip side of the arm part 102 as shown in Figure 11, and can also be moved to the base end side of the arm part 102 or its vicinity, although this is not shown. The stylus holder 101 can be stopped at any position relative to the arm part 102. The position of the stylus holder 101 is detected by position detection means such as a rotary encoder and output to the control part 3d.

[0096] 11 shows a state in which the styluses 83A, 83B, and 83C held by the stylus holder 101 have been moved to an attachable position where they can be attached to the housing 81. The position of the changer turning drive unit 103 is set so that the rotation axis 103a of the changer turning drive unit 103 is located between the styluses 83A, 83B, and 83C at the attachable position and the styluses 83A, 83B, and 83C at the retracted position, and the changer turning drive unit 103 at this position is attached to the support unit 22.

[0097] The changer turning drive unit 103 turns the arm unit 102 by 180° when moving the stylus holder 101 from the retracted position to the attachable position, or from the attachable position to the retracted position. In other words, the position of the stylus holder 101 can be switched significantly from the front to the rear of the changer turning drive unit 103, or from the rear to the front.

[0098] Next, a procedure for replacing a stylus will be described. FIG. 13 is a flowchart showing an example of a stylus attachment procedure. In step SA1 after starting, the control unit 3d of the control unit 3 controls the Z-direction drive unit 25 to move the measurement execution unit 24 to the upper standby position. In step SA2, the control unit 3d controls the changer feed drive unit 104 to move the stylus holder 101 in the longitudinal direction of the arm unit 102 so that a desired notch (assumed to be the first notch 101a) among the first to third notches 101a, 101b, and 101c is positioned in a predetermined position. As a result, the stylus holder 101 moves outward from the space directly below the eaves portion 22A (for example, the stylus holder 101 moves to near the center of the arm unit 102 and comes outward from the eaves portion 22A). In step SA3, the control unit 3d controls the changer rotation drive unit 103 to rotate the arm unit 102 and place the stylus holder 101 in an attachment position. This state is shown in FIG. 14A of FIG. 14, and since the measurement execution unit 24 is in the upper standby position, the stylus 83A has not yet been attached to the housing 81. After step SA3, the position of the stylus holder 101 may be fine-tuned along the longitudinal direction of the arm unit 102.

[0099] Then, the process proceeds to step SA4, where the control unit 3d controls the Z-direction drive unit 25 to lower the measurement execution unit 24 and move it to the installation height. Then, the lower cylindrical member 83a of the stylus 83A is attracted to the upper cylindrical member 82a of the probe shaft 82 by magnetic force. The state after attraction is shown in FIG. 14B of FIG. 14. Next, the process proceeds to step SA5, where the control unit 3d controls the changer pivot drive unit 103 to rotate the arm unit 102 and place the stylus holder 101 in the retracted position. At this time, the holding claws 101d elastically deform, and the lower cylindrical member 83a comes out of the holding claws 101d.

[0100] Next, the procedure for removing the stylus attached to the housing 81 is shown in FIG. 15. In step SB1 after starting, similar to step SA4, the control unit 3d of the control unit 3 controls the Z-direction drive unit 25 to move the measurement execution unit 24 to the attachment height. In step SB2, the control unit 3d controls the changer feed drive unit 104 to move the stylus holder 101 in the longitudinal direction of the arm unit 102 so that the desired notch (assumed to be the first notch 101a) among the first to third notches 101a, 101b, and 101c is positioned in a predetermined position. At this time, the notch not holding the stylus is positioned in a predetermined position. The stylus holder 101 also moves outward from the space directly below the eaves portion 22A (for example, the stylus holder 101 moves near the center of the arm unit 102 and moves outside the eaves portion 22A).

[0101] In step SB3, the control unit 3d controls the changer pivot drive unit 103 to rotate the arm unit 102 and place the stylus holder 101 in an attachable position. This flow is for removal and is therefore not "attachable," but since the position of the stylus holder 101 is the same as the "attachable position" in the flow shown in Figure 13, it is also referred to as the "attachable position" in this flow. The "attachable position" may also be referred to as the "removable position." This state is shown in Figure 14B in Figure 14, where the holding claw 101d engages with the portion of the lower cylindrical member 83a of the stylus 83A where the groove 83d is formed.

[0102] Then, the process proceeds to step SB4, where the control unit 3d controls the Z-direction drive unit 25 to raise the measurement execution unit 24 and move it to the upper standby position. This causes the upper cylindrical member 82a of the probe shaft 82 to move upward relative to the lower cylindrical member 83a of the stylus 83A, and the lower cylindrical member 83a of the stylus 83A separates from the upper cylindrical member 82a of the probe shaft 82 against the magnetic force. The state after separation is as shown in FIG. 14A of FIG. 14. Next, the process proceeds to step SB5, where the control unit 3d controls the changer pivot drive unit 103 to rotate the arm unit 102 and place the stylus holder 101 in the retracted position.

[0103] As described above, the control unit 3d controls the changer rotation drive unit 103 and the changer feed drive unit 104 so that the stylus held by the stylus holding unit 101 is moved from the retracted position to the attachable position, and also controls the changer rotation drive unit 103 and the changer feed drive unit 104 so that the stylus held by the stylus holding unit 101 is moved from the attachable position to the retracted position. The control unit 3d also controls the changer feed drive unit 104 so that the stylus holding unit 101 in the retracted position is positioned closer to the base end of the arm unit 102 than the stylus holding unit 101 in the attachable position.

[0104] In this embodiment, the holding claws 101d are configured to engage with grooves 83d formed in the outer peripheral surface of the lower cylindrical member 83a. However, a modified example in which the grooves 83d are not formed is also conceivable. For example, a movable member (preferably an elastic member) that moves radially relative to (contacts or moves away from) the outer peripheral surface of the lower cylindrical member 83a may be provided inside the cutouts 101a to 101c. This movable member may be moved by the control unit 3d. In this case, in step SA4 described above, after the lower cylindrical member 83a of the stylus 83A is attracted to the upper cylindrical member 82a of the probe shaft 82, the control unit 3d controls the movable member to move away from the outer peripheral surface of the lower cylindrical member 83a. Furthermore, in step SB4 described above, before the measurement unit 24 is raised to the upper standby position, the control unit 3d controls the movable member to abut against the outer peripheral surface of the lower cylindrical member 83a. In this way, the stylus 83A may be attached and detached without forming the groove 83d on the outer peripheral surface of the lower cylindrical member 83a.

[0105] (Control unit configuration) The control unit 3 shown in FIG. 6 includes, for example, a CPU (Central Processing Unit), RAM, ROM, an internal bus, etc. (not shown). The CPU is connected to the display unit 4, keyboard 5, mouse 6, storage unit 7, and device main body 2 via the internal bus. The control unit 3 acquires the operation status of the keyboard 5, mouse 6, measurement start button 2a of device main body 2, etc. The control unit 3 can also acquire image data acquired by the imaging unit 50, first stage camera 46, second stage camera 47, and front camera 48 of the device main body 2. The control unit 3 can also display the results of calculations performed within the control unit 3, as well as image data acquired by the imaging unit 50, first stage camera 46, second stage camera 47, and front camera 48, on the display unit 4.

[0106] The control unit 3 also controls the Z-direction drive unit 25, XY-direction drive unit 23, coaxial epi-illumination 40, ring illumination 45, illumination Z-direction drive unit 45d, imaging unit 50, non-contact displacement meter 70, touch probe 80, changer rotation drive unit 103, changer feed drive unit 104, and other components of the apparatus main body 2. Specifically, the control unit 3 is connected to each piece of hardware via an internal bus, so it controls the operation of the above-mentioned hardware and also executes various software functions in accordance with computer programs stored in the storage unit 7. For example, the control unit 3 is provided with an image measurement unit 3a that measures the dimensions of the workpiece W based on a workpiece image generated by the imaging unit 50, a coordinate measurement unit 3b that measures the three-dimensional coordinates of the contact point where the touch probe 80 comes into contact with the workpiece W, and a displacement measurement unit 3c that measures the displacement of the workpiece W on the stage 21 based on an output signal from the non-contact displacement meter 70. Displacement measurement is also called height measurement.

[0107] Hereinafter, the details of the functions that the control unit 3 can execute will be explained separately for the measurement setting time before measuring the workpiece W and the measurement execution time when the measurement of the workpiece W is executed.

[0108] (When setting up measurement) 16 is a flowchart showing an example of the procedure for setting up measurement for the image measuring device 1. In step SC1 after starting, a planar image is generated. That is, the imaging unit 50 images the stage 21. At this time, if the user places the workpiece W on the mounting table 21a of the stage 21, an image of the workpiece is acquired. For example, after the Z-direction driving unit 25 moves the measurement execution unit 24 to move the imaging unit 50 to the measurement position, the imaging unit 50 can image the workpiece W on the stage 21 and can also illuminate it as needed.

[0109] In step SC2, an overhead image is generated. After the measurement execution unit 24 is moved by the Z direction drive unit 25 to move the front camera 48 to the measurement position, the front camera 48 captures an image of the workpiece W on the stage 21.

[0110] When capturing an image of the workpiece W with the front camera 48, the following control can be performed. That is, first, the control unit 3d detects the position of the workpiece W on the stage 21 based on the workpiece image generated by the imaging unit 50. Then, the control unit 3d determines whether the workpiece W on the stage 21 is located within the field of view of the front camera 48 based on the detected position of the workpiece W on the stage 21 and the known field of view of the front camera 48. Next, if the workpiece W on the stage 21 is located outside the field of view of the front camera 48, the control unit 3d controls the XY direction drive unit 23 to move the stage 21 so that the workpiece W on the stage 21 is located within the field of view of the front camera 48. This allows the front camera 48 to reliably capture an image of the workpiece W on the stage 21.

[0111] In addition, after capturing an image of the workpiece W on the stage 21 with the front camera 48, the control unit 3d can control the XY direction drive unit 23 to move the stage 21, and capture an image of another area on the stage 21 with the front camera 48.

[0112] Position information of the stage 21 when an overhead image is captured by the front camera 48 can be obtained using the X-direction linear scale 23a or the Y-direction linear scale 23b. The obtained position information of the stage 21 can be associated with the overhead image and stored in the storage unit 7. This makes it possible to know the position of the stage 21 when the overhead image was captured.

[0113] In step SC3, it is determined whether or not to generate a color workpiece image (color image) based on the user's selection. If the user desires to generate a color image, he or she selects generation of a color image on the user interface screen displayed on the display unit 4; if not, he or she does not select generation of a color image. The user's selection operation is performed using the keyboard 5, mouse 6, etc., and is received by the reception unit 3e of the control unit 3.

[0114] If the user does not wish to generate a color image, i.e., if it is determined in step SC3 that a color image will not be generated, the process proceeds to step SC4, where a grayscale work image (grayscale image) is generated based on data acquired by the imaging unit 50 using monochromatic light illumination. On the other hand, if the user wishes to generate a color image, i.e., if it is determined in step SC3 that a color image will be generated, the process proceeds to step SC5, where a color image is generated.

[0115] The image generation of steps SC4 and SC5 will be described in detail based on the flowchart shown in FIG. 17. In step SD1 after the start in FIG. 17, the workpiece W is illuminated by the transmitted light 30. In step SD2, the XY-direction drive unit 23 is controlled to move the stage 21 in the X or Y direction, and the workpiece W is searched for while being imaged by the imaging unit 50. The stage 21 is moved, for example, in a spiral shape from the center in the X direction and the center in the Y direction. Then, when the ratio of black pixels (pixels with a brightness value below a predetermined value) in the image captured by the imaging unit 50 reaches a certain level or more, it is determined that the workpiece W is present in that area. In this way, the workpiece W is searched for, and the position of the workpiece W on the stage 21 can be identified, as well as the size of the workpiece W and the area of ​​the stage 21 occupied by the workpiece W, etc.

[0116] In step SD3, the workpiece W found in step SD2 is imaged by the imaging unit 50. At this time, when generating a grayscale image, the red light source 45a, the green light source 45b, and the blue light source 45c of the ring illumination 45 are all turned on to illuminate the workpiece W with white light, and the image is captured by the imaging unit 50.

[0117] On the other hand, when generating a color image, the grayscale workpiece image is acquired, and the color information generating section 3f of the control unit 3 generates color information of the workpiece W based on a plurality of workpiece images generated by the imaging section 50 each time detection light of a plurality of different wavelengths is irradiated from the ring illumination 45. Specifically, a workpiece image under red illumination captured by the imaging section 50 with only the red light source 45a turned on, a workpiece image under green illumination captured by the imaging section 50 with only the green light source 45b turned on, and a workpiece image under blue illumination captured by the imaging section 50 with only the blue light source 45c turned on are generated. The color information generating section 3f acquires hue and saturation as color information from these three workpiece images.

[0118] The control unit 3d generates a color image by adding the workpiece color information generated by the color information generation unit 3f to a grayscale workpiece image. Here, an RGB image consisting of three channels (red, green, and blue) can be converted into an HSV image consisting of hue (H), saturation (S), and brightness (V). The color information corresponds to hue (H) and saturation (S). To add color information to a single-channel image, a new color image can be generated by treating the single-channel image as brightness (V) and assigning desired color information to the hue (H) and saturation (H). In this example, the color image is generated by combining the hue and saturation acquired by the color information generation unit 3f with the brightness of the grayscale workpiece image. The color space is not limited to HSV; other color spaces, such as HLS, can also be used.

[0119] When generating a color image, the grayscale workpiece image is an image directly used for measurement, and therefore is a high-magnification image captured by the high-magnification side image sensor 55, while the workpiece images for generating color information, i.e., the workpiece image under red illumination, green illumination, and blue illumination, are low-magnification images captured by the low-magnification side image sensor 56. Therefore, a color image is obtained by adding color information generated based on the low-magnification image to the grayscale workpiece image, which is a high-magnification image. Since imaging by the low-magnification side image sensor 56 results in a deep depth, color information with a wide range and deep depth can be obtained in a short time by acquiring the workpiece image for generating color information with the low-magnification side image sensor 56. The acquired color information can be added to the workpiece image captured by the high-magnification side image sensor 55, which has a shallow depth.

[0120] The grayscale workpiece image can be an image captured under different shooting conditions (exposure, lighting intensity, lighting type, lens magnification, etc.) from the workpiece image used to generate color information. Alternatively, color information can be added to a workpiece image under different lighting conditions, focus conditions, etc. Furthermore, even if the image captured in real time by the imaging unit 50 is a single-channel image, it is possible to add the color information acquired by the color information generating unit 3f.

[0121] Next, the process proceeds to step SD4. In step SD4, it is determined whether or not imaging of an area adjacent to the area imaged in step SD3 is necessary. The search results of step SD2 are used in this determination. If a workpiece W exists outside the area imaged in step SD3 and imaging of that area is necessary, a YES determination is made in step SD4 and the process proceeds to step SD5. In step SD5, the XY-direction drive unit 23 is controlled to move the stage 21 so that another portion of the workpiece W is included in the imaging field of view of the imaging unit 50. The process then proceeds to step SD3, where an image of a portion different from the portion imaged the first time is captured by the imaging unit 50. Steps SD5 and SD3 are repeated as many times as necessary, and a linking process is performed to link the acquired multiple workpiece images. That is, the control unit 3d controls the XY-direction drive unit 23 and the imaging unit 50 to generate multiple workpiece images of different portions of the workpiece, and then links the generated multiple workpiece images to generate a linked image, which is an image of an area wider than the imaging field of view of the imaging unit 50. The color information of the workpiece generated by the color information generation unit 3f is also added to the linked image. This allows a color linked image to be acquired. If the determination in step SD4 is NO, no further imaging is required, and this flow is terminated.

[0122] The process then proceeds to step SC6 of the flowchart shown in Fig. 16. In step SC6, if a color image was generated in step SC5, the control unit 3d causes the display unit 4 to display the color image, and if a grayscale image was generated in step SC4, the control unit 3d causes the display unit 4 to display the grayscale image. Furthermore, if a concatenated image was generated, the control unit 3d causes the display unit 4 to display the color concatenated image or the grayscale concatenated image. Furthermore, if a live view image was generated, the control unit 3d causes the display unit 4 to display the color live view image or the grayscale live view image.

[0123] In step SC6, the overhead image captured by the front camera 48 can also be displayed on the display unit 4. If the front camera 48 captures a plurality of overhead images, the plurality of overhead images can be displayed as thumbnails on the display unit 4. That is, the overhead images are reduced and displayed side by side in a predetermined direction, and when the user selects any one of the reduced images, the control unit 3d causes the display unit 4 to display the overhead image corresponding to the selected reduced image.

[0124] In step SC7, the measuring means is determined. The measuring means includes an image measuring unit 3a that measures the dimensions of the workpiece W based on an image of the workpiece, a coordinate measuring unit 3b that measures three-dimensional coordinates using a touch probe 80, and a displacement measuring unit 3c that measures displacement using a non-contact displacement meter 70. The user can select any measuring means from the image measuring unit 3a, coordinate measuring unit 3b, and displacement measuring unit 3c. For example, when a measuring means selection operation is performed on the user interface screen displayed on the display unit 4, the selection operation is received by the receiving unit 3e.

[0125] If it is determined in step SC7 that the image measurement unit 3a has been selected, the process proceeds to step SC8; if it is determined that the coordinate measurement unit 3b has been selected, the process proceeds to step SC9; and if it is determined that the displacement measurement unit 3c has been selected, the process proceeds to step SC10.

[0126] Details of the case where image measurement is selected (step SC8) are shown in the flowchart in Fig. 18. In step SE1 after the start, the control unit 3d changes the imaging conditions to those corresponding to the image measurement of the workpiece W. The imaging conditions include illumination, exposure time, etc.

[0127] In step SE2, the reception unit 3e receives the user's designation of the shape type. In step SE3, the reception unit 3e receives the user's designation of the edge extraction area. The edge extraction area can be extracted as an edge on the workpiece image and used for measurement. In step SE4, the imaging unit 50 images the workpiece W on the stage 21. In step SE5, multiple edge points are detected on the workpiece image acquired in step SE4. The edge points can be detected based on changes in brightness values ​​on the workpiece image. In step SE6, a fitting line passing through the multiple edge points is calculated. Then, in step SE7, the image measurement unit 3a calculates the dimensions using the fitting line. The image measurement unit 3a measures the dimensions of the workpiece W based on the high-magnification image generated by the high-magnification side imaging element 55.

[0128] Details of the case where coordinate measurement is selected (step SC9) are shown in the flowchart of Fig. 19. Steps SF1 to SF6 after start are the same as SE1 to SE6 in the flowchart shown in Fig. 18. Then, in step SF7, a scan line for coordinate measurement, i.e., a scan line of the touch probe 80, is calculated. In step SF8, a measurement operation is performed by the touch probe 80, and then, in step SF9, a fitting line is calculated again, and then, in step SF10, the coordinate measurement unit 3b calculates the dimensions.

[0129] Here, coordinate measurement will be described in detail with reference to a specific example. Fig. 20 is a perspective view showing a state in which the workpiece W is placed on the stage 21, and Fig. 21 is a planar image captured from above of the state in which the workpiece W is placed on the stage 21. In Figs. 20 and 21, absolute coordinates in the three-dimensional space surrounded by the stage 21, the support part 22 (shown in Fig. 2, etc.), and the imaging part 50 are indicated by X, Y, and Z.

[0130] The workpiece W has a side surface S1 extending along the Z direction, a top surface S2 extending along the X and Y directions, an inclined surface S3 inclined at a predetermined angle with respect to the Z direction, and a hole H1 opening in the top surface S2 and extending along the Z direction. In addition, an alignment mark M for positioning is provided on the top surface S2.

[0131] During measurement setup, a planar image of the workpiece W as shown in FIG. 21 is displayed on the display unit 4. On the workpiece image displayed on the display unit 4, the user associates and sets a first contact target position P1, which serves as a reference for contacting the side surface S1 of the workpiece W with the touch probe 80 from the X and Y directions, a second contact target position P2, which serves as a reference for contacting the top surface S2 of the workpiece W from the Z direction, and a feature pattern for identifying the position and orientation of the workpiece W when performing measurement. The setting unit 3g of the control unit 3 enables the above settings. Note that the "first contact target position P1" and "second contact target position P2" referred to here are concepts that include not only the contact point where the touch probe 80 contacts the workpiece W, but also the operation start position and end position, which will be described later.

[0132] In this example, the feature pattern is an alignment mark M. When setting the feature pattern, the user operates the mouse 6 or the like to specify an area on the workpiece image so that the feature pattern is included, as shown by the rectangular frame 200 in FIG. 21. The method for setting the feature pattern is not limited to the example shown in the figure, and the area may be specified using a free curve, or only the feature pattern may be specified. The feature pattern may also be set by a method in which the setting unit 3g automatically extracts it.

[0133] The feature pattern may be a shape, pattern, color, symbol, character, or the like of a part of the workpiece W, and may also be called feature amount information. Furthermore, the feature pattern may be any type of information as long as it is information for identifying the position and posture of the workpiece W on the workpiece image displayed on the display unit 4 when measurement is performed. The feature amount information may be made up of multiple feature patterns.

[0134] 21, a third contact target position P3 and a fourth contact target position P4 are also set. The third contact target position P3 is a reference position for bringing the touch probe 80 into contact with the inner surface of the hole H1 in the workpiece W from the X and Y directions, and the fourth contact target position P4 is a reference position for bringing the touch probe 80 into contact with the inclined surface S3 of the workpiece W from the normal direction of the inclined surface S3. The setting unit 3g can also set the third contact target position P3, the fourth contact target position P4, and the feature pattern in association with each other.

[0135] A plurality of first contact target positions P1 can be set based on the above absolute coordinates, and a plurality of first contact target positions P1 can be set at intervals in the Y direction as shown in Fig. 21, and a plurality of first contact target positions P1 can be set at intervals in the Z direction as shown in Fig. 22. As shown in Figs. 22 and 23, a vertical cross section of the workpiece W can be displayed on the display unit 4. Each setting can also be made on the vertical cross section of the workpiece W.

[0136] As shown by the frame line 201 in FIG. 21, the setting unit 3g extracts and sets the side surface S1 of the workpiece W as a first edge measurement element (straight edge element) on the workpiece image. Because the first edge measurement element corresponds to the outer surface of the workpiece W, it can be extracted accurately and clearly by illumination with transmitted illumination 30. The setting unit 3g sets the first edge measurement element in association with the extracted first contact target position P1. In addition to the automatic setting described above, the edge can also be set manually by the user by operating the mouse 6 or the like.

[0137] For example, the control unit 3d can generate a user interface screen 210 for setting a contact target position as shown in FIG. 23 and display it on the display unit 4. The setting user interface screen 210 includes a cross-section display area 211 that displays a cross-section of the workpiece W, and a parameter setting area 212. In the parameter setting area 212, multiple parameters for setting the first contact target position P1 can be set. For example, the number of measurement points in the X and Y directions can be set as a horizontal parameter. In this example, since there are two measurement points in the X and Y directions as shown in FIG. 21, two measurement points are set in the X and Y directions, but the number of measurement points is not limited to this. Measurement points are displayed on the display unit 4 as many times as the number of set measurement points. The number of measurement points is the number at which the contact target position of the touch probe 80 is to be arranged.

[0138] The setting unit 3g can set the position in the X and Y directions on the workpiece image when setting the first contact target position P1. For example, the position in the X and Y directions of the first contact target position P1 is set by moving the first contact target position P1 on the workpiece image using the mouse 6 or the like. The position in the X and Y directions of the first contact target position P1 can also be set arbitrarily by inputting the distance from the reference position, for example, separately in the X and Y directions using the keyboard 5 or the like. Furthermore, the height position in the Z direction of the first contact target position P1 can also be set in a similar manner.

[0139] The horizontal direction parameters may include a setting parameter for the measurement direction. The measurement direction is the approach direction of the touch probe 80 to the contact target position. The measurement direction shown in FIG. 23 is from right to left as indicated by the arrow, but depending on the workpiece W, the opposite direction may be desired. In this case, the user checks "reverse" to select the reverse direction. This operation is set in the setting unit 3g and then stored in the memory unit 7 as the approach direction.

[0140] The approach directions include a first approach direction in which the touch probe 80 is moved from above toward the workpiece W to approach it, and a second approach direction in which the touch probe 80 is moved in a normal direction toward the inclined surface S3 of the workpiece W, and the approach direction can be selected arbitrarily by the user.

[0141] As vertical direction parameters, it is possible to set the number of measurement points in the Z direction, the start margin, and the measurement range. In this example, the number of measurement points in the Z direction is set to two. The start margin is the dimension in the Z direction from the top surface S2 of the workpiece W to the first upper contact target position P1. The measurement range is the dimension from the upper first contact target position P1 to the lower first contact target position P1.

[0142] In the parameter setting area 212, parameters related to the scan line can also be set. A scan line can also be defined as a path along which the touch probe 80 moves from a position where it is not in contact with the workpiece W to a position where it is in contact with the workpiece W. The parameters related to the scan line become path information for the touch probe 80 when the touch probe 80 approaches the workpiece W, and the approach path of the touch probe 80 to the target contact position can become the scan line. The scan line may be straight or curved.

[0143] The start position (start point) of the scan line is the operation start position of the touch probe 80, and this start position can be set using specific dimensions, depending on how far it is horizontally from the edge position of the side surface S1 of the workpiece W. Also, the end position of the scan line can be set using specific dimensions, depending on how far it is from the edge position of the side surface S1 of the workpiece W toward the cross section of the workpiece W. Even if the scan line has reached the cross section of the workpiece W, scanning will automatically stop when the touch probe 80 comes into contact with the workpiece W.

[0144] A plurality of second contact target positions P2 can also be set based on the above absolute coordinates, and can be set at intervals in the X and Y directions as shown in FIG. 21. The parameters of the second contact target position P2 differ from the parameters of the first contact target position P1, and the number of measurement points in the X direction and the Y direction are set. Setting of parameters for the vertical direction is omitted. The setting unit 3g extracts and sets the line that forms the boundary between the top surface S2 and the inclined surface S3 of the workpiece W on the workpiece image as a second edge measurement element (straight edge element), but the second edge measurement element (the portion surrounded by the frame line 202) and the second contact target position P2 are not associated with each other.

[0145] The third contact target position P3 can also be set multiple times based on the above absolute coordinates. It is possible to set multiple third contact target positions P3 at intervals in the circumferential direction of the hole H1, or multiple third contact target positions P3 at intervals in the Z direction. For the hole H1, the starting position is the position approaching the central axis from the inner surface of the hole H1 in a plan view. The approach direction is the direction from the position approaching the central axis from the inner surface of the hole H1 toward the inner surface of the hole H1, and this direction can also be set using a user interface such as that shown in Figure 23. Furthermore, for the hole H1, measurement points are arranged in a circumferential direction, and the number of measurement points can also be set. The parameters of the third contact target position P3 can be set in the same way as the parameters of the first contact target position P1.

[0146] The setting unit 3g extracts and sets the peripheral portion of the hole H1 as a third edge measurement element (circular edge element) on the workpiece image. The setting unit 3g associates the extracted third edge measurement element (the portion surrounded by the frame line 203) with a third contact target position P3 and sets it. If the workpiece W has a cylindrical portion, the measurement point of the cylindrical portion can be set in a similar manner.

[0147] Multiple fourth contact target positions P4 can also be set based on the absolute coordinates. FIG. 24 shows a user interface screen 210 for setting contact target positions for a slope. The horizontal direction parameters in the parameter setting area 212 are the same as when setting the first contact target position P1, but the inclination direction parameters are different. The inclination direction parameters allow for setting the number of measurement points in the inclination direction, the start margin, and the measurement range. The start margin is the dimension along the slope S3 from the second edge measurement element shown in FIG. 21 to the upper fourth contact target position P4. The measurement range is the dimension from the upper fourth contact target position P4 to the lower fourth contact target position P4. The inclination angle α of the slope S3 can also be set. The inclination angle α of the slope S3 is angle information near the contact target position of the touch probe 80, and input of this inclination angle α can also be accepted by the setting unit 3g. Furthermore, the setting unit 3g sets a fourth contact target position P4 in association with the second edge measurement element (the portion surrounded by a frame line 202 in FIG. 21). The various setting information set as described above is stored in the storage unit 7.

[0148] When setting up the measurement, it is also possible to set a measurement range for dimension measurement. For example, if the user wants to measure only the top surface S2 of the workpiece W, the user sets the measurement range on the workpiece image displayed on the display unit 4 so that it surrounds only the top surface S2. The reception unit 3e is configured to be able to accept the measurement range setting made by the user. The measurement range setting information accepted by the reception unit 3e is also stored in the memory unit 7.

[0149] Next, the details of step SC10 (measurement using the non-contact displacement meter 70) in the flowchart shown in FIG. 16 are shown in the flowchart shown in FIG. 25. After starting, in step SG1, parameters for non-contact displacement measurement are set. Then, proceeding to step SG2, the control unit 3d accepts specification of a height measurement point on the workpiece image. In step SG2, a position in the XY direction is specified. For example, the user may confirm the desired measurement point while looking at the workpiece image displayed on the display unit 4 and specify the measurement point using the mouse 6 or the like, or may specify the measurement point by inputting position specification information such as coordinates as numerical values. Multiple measurement points can be specified.

[0150] After the measurement location is specified, the process proceeds to step SG3, where the control unit 3d controls the stage 21 so that the measurement light of the non-contact displacement meter 70 is irradiated onto the measurement location specified in step SG2. Specifically, the control unit 3d controls the Z-direction driver 25 and the XY-direction driver 23 to align the focus of the non-contact displacement meter 70 with the measurement location specified in step SG2. Then, in step SG4, the measurement light is emitted and measurement is performed. In step SG5, the displacement measurement unit 3c calculates the dimensions. At this time, an averaging process, which will be described later, may be performed.

[0151] After step SC10 in the flowchart of Fig. 16, the process proceeds to step SC11. In step SC11, a measurement tool is set. For example, a tool for measuring the distance between lines, a tool for measuring diameters, a tool for measuring angles, etc. can be displayed in a list format on the display unit 4, allowing the user to select a desired tool. The measurement tool selected by the user is saved.

[0152] In step SC12, the measurement results obtained by the measurement tool set in step SC11 are superimposed on the workpiece image on the display unit 4. If a color image has been acquired, the measurement results are superimposed on the color image. The setting of the range in which the measurement results are to be superimposed can also be accepted in advance by the acceptance unit 3e. When setting up the measurement, for example, if the user specifies the range in which the measurement results are to be superimposed on the color image displayed on the display unit 4, that range is accepted by the acceptance unit 3e and then stored in the memory unit 7. When the measurement is performed, the specified range is read from the memory unit 7, and the measurement results are superimposed only within the specified range. Note that if a live view image has been acquired, the measurement results can also be displayed on a moving image.

[0153] Furthermore, in step SC13, for example, when measurement results are acquired by the image measurement unit 3a, the measurement results of the image measurement unit 3a are superimposed and displayed on the overhead image generated by the front camera 48. In step SC13, for example, as shown in FIG. 26, geometric elements 221 and 222 corresponding to the measurement results of the image measurement unit 3a can also be displayed on the overhead image. FIG. 26 is another example of a user interface screen 220 for displaying geometric elements 221 and 222 (shown by thick lines) on the display unit 4, in which the workpiece image and the geometric elements 221 and 222 corresponding to the shapes of the measurement elements of the workpiece image are superimposed and displayed. The geometric elements 221 and 222 may be straight lines, circles, rectangles, etc., as long as they have a shape corresponding to the measurement elements. The geometric elements 221 and 222 are set as edge measurement elements by the setting unit 3g, and include straight edges, circular edges, rectangular edges, etc.

[0154] The number and position of the contact target position of the touch probe 80 can be associated with each measurement element. For example, different positions for the contact target position can be associated with the geometric element 221 and the geometric element 222, and different numbers of contact target positions can also be associated with them. The correspondence between the shape type or size of the measurement element and the number and position of the contact target position of the touch probe 80 relative to the measurement element can be stored in the storage unit 7. The shape type, size, etc. of the geometric element can also be set on the overhead image.

[0155] The overhead image is an image generated by the front camera 48, whereas the workpiece image from which the geometric elements 221 and 222 have been extracted is an image generated by an imaging unit 50 different from the front camera 48. Therefore, if the geometric elements are superimposed on the overhead image without correction, there is a risk of misalignment. In response to this, the present example is configured to be able to execute a correction process that corrects the misalignment of the geometric elements relative to the overhead image before measurement. Examples of misalignment of the geometric elements include misalignment due to the optical characteristics of the camera or lens, and misalignment of the camera. The correction process may be performed when the image measuring device 1 is shipped from the factory, or may be performed after shipping. Any method of correction may be used, and an example is shown below.

[0156] For the correction process, a correction workpiece (not shown) having, for example, a dot chart or the like is prepared and placed on the stage 21. The correction workpiece on the stage 21 is imaged by the imaging unit 50, and the central coordinates of each dot are detected. The front camera 48 also images the correction workpiece on the stage 21, and the central coordinates of each dot are detected. A correction table is generated as an internal parameter so that the central coordinates detected based on the image of the imaging unit 50 can be converted to the central coordinates detected based on the image of the front camera 48. A conversion function may be used instead of the correction table. The correction table is then applied to the image captured by the imaging unit 50 to convert it into projective coordinates.

[0157] The correction process also includes, for example, a process for detecting external parameters. That is, the image of the workpiece to be corrected on the stage 21 is captured by the imaging unit 50, and the three-dimensional coordinates of the center of each dot are detected. The center coordinates of each dot in projective coordinates are obtained from the image of the front camera 48 using internal parameters. A transformation matrix for these corresponding images is then calculated. In addition, the positions and orientations of the imaging unit 50 and the front camera 48 are determined within three-dimensional space. A transformation matrix is ​​then calculated between the center coordinates of the detected dots detected based on the image of the imaging unit 50 and the center coordinates detected based on the image of the front camera 48.

[0158] In step SC13 of the flowchart shown in FIG. 16, as shown in FIG. 27, the measurement results and geometric elements 231 and 232 may be superimposed and displayed on a user interface screen 230 capable of displaying the workpiece W in three dimensions.

[0159] In step SC14, it is determined whether there are any other measurement elements. If there are other measurement elements, the process returns to step SC7. If there are no other measurement elements, the process proceeds to step SC15. In step SC15, pattern search settings are made. For example, as shown in FIG. 21, an alignment mark M, which is a characteristic pattern, can be set as the search target. In this case, the user can generate a frame 200 that surrounds the alignment mark M and specify the area within that frame 200 as the search area.

[0160] In step SC16, the setting information set in each process shown in this flowchart is stored in the storage unit 7. That is, the feature pattern (feature amount information) set by the setting unit 3g, the relative positional relationship of the first and second contact target positions P1, P2 with respect to the feature pattern, etc. are stored. The storage unit 7 also stores the fixed positional relationship between the imaging unit 50 and the touch probe 80, etc. The fixed positional relationship is the relative positional relationship of the touch probe 80 with respect to the imaging unit 50, and may be, for example, a relationship indicated by coordinate information, or a relationship indicated by a relative separation distance or separation direction, etc.

[0161] (Touch probe measurement operation) Next, the details of the measurement operation of the touch probe 80, i.e., the details of step SF8 in the flowchart shown in FIG. 19, will be described with reference to the flowchart shown in FIG. 28. After starting, although not shown in the flowchart, the control unit 3d controls the Z-direction driver 25 to move the measurement execution unit 24 upward to the retracted position, and then uses the changer mechanism 100 to attach the desired stylus 83 to the touch probe 80. Then, the process proceeds to step SH1, where the contact portion 83b of the touch probe 80 is moved relatively to the start point of the scan line set on the setting user interface screen 210 shown in FIG. 23. Specifically, the control unit 3d controls the XY-direction driver 23 to move the stage 21 in the X and Y directions, thereby matching the XY coordinates of the start point of the scan line with the XY coordinates of the contact portion 83b of the touch probe 80. Then, the control unit 3d controls the Z-direction driver 25 to lower the measurement execution unit 24, thereby positioning the contact portion 83b of the touch probe 80 at the start point of the scan line.

[0162] In step SH2, the control unit 3d controls the XY-direction drive unit 23 and the Z-direction drive unit 25 to move the contact portion 83b of the touch probe 80 relatively in the direction of the scan line (the direction of the arrow in Figures 23 and 24). In step SH3, it is determined whether the touch probe 80 has detected contact. If the touch probe 80 does not detect contact, the contact portion 83b of the touch probe 80 continues to move relatively in the direction of the scan line. When the contact portion 83b of the touch probe 80 comes into contact with the workpiece W, the movement is stopped, and step SH3 is determined as YES, and the process proceeds to step SH4.

[0163] In step SH4, the coordinate measuring unit 3b acquires the X, Y, and Z coordinates when the contact portion 83b of the touch probe 80 comes into contact with the workpiece W, and uses these as the measurement values. In step SH5, the control unit 3d controls the XY-direction driving unit 23 and the Z-direction driving unit 25 to return the contact portion 83b of the touch probe 80 to the start point of the scan line. In step SH6, it is determined whether measurement has been completed for all scan lines. If measurement of all scan lines has been completed, the process proceeds to step SH7, where the control unit 3d controls the Z-direction driving unit 25 to move the measurement execution unit 24 upward to the retracted position. Thereafter, if necessary, the stylus 83 is removed by the changer mechanism 100 and stored in the retracted position.

[0164] If step SH6 returns NO and there are scan lines for which measurement has not been completed, the process proceeds to step SH8, where the retraction method is determined. If the retraction method is a method of retracting in the Z direction, the process proceeds to step SH9, where the control unit 3d controls the Z-direction drive unit 25 to move the measurement execution unit 24 upward to the retracted position. In step SH10, the control unit 3d controls the XY-direction drive unit 23 to relatively move the contact portion 83b of the touch probe 80 to the start point (X, Y) of the scan line. Thereafter, in step SH11, the control unit 3d controls the Z-direction drive unit 25 to relatively move the contact portion 83b of the touch probe 80 to the start point (Z) of the scan line.

[0165] If the retraction method is the polygon retraction method, the process proceeds to step SH12. In step SH12, the control unit 3d controls the XY direction drive unit 23 to relatively move the center of the contact part 83b of the touch probe 80 to the start point (X, Y) of the scan line so as to form a polygon along the circumferential direction of the measurement element.

[0166] If not, the process proceeds to step SH13, where the control unit 3d controls the XY direction drive unit 23 to relatively move the contact portion 83b of the touch probe 80 to the start point (X, Y) of the scan line.

[0167] (When measuring) 29A and 29B are flowcharts showing an example of the procedure for performing measurement with the image measuring device 1. In step SI1 after starting, setting information stored in the memory unit 7 is read out. For example, the feature pattern, search area, the relative positional relationship of the first and second contact target positions P1 and P2 with respect to the feature pattern, and the fixed positional relationship between the imaging unit 50 and the touch probe 80 are read out. This step eliminates the need for the user to move the touch probe 80 and set reference coordinates every time a workpiece W is placed on the stage 21, simplifying the measurement process.

[0168] In step SI1, the positions of the measurement elements on the workpiece image and the shape type or size of the measurement elements are read from the storage unit 7. Furthermore, the correspondence between the shape type or size of the measurement elements and the positions and number of the contact target positions of the touch probe 80 relative to the measurement elements is also read from the storage unit 7.

[0169] In step SI2, the imaging unit 50 captures an image of the stage 21 from above, acquires a planar image, and displays it on the display unit 4. In step SI2, a combined image may be displayed, or an overhead image captured by the front camera 48 may be displayed. The imaging unit 50 may acquire a combined image using either the high-magnification side imaging element 55 or the low-magnification side imaging element 56, or may acquire a combined image using both imaging elements. As described above, this embodiment employs a bifurcated optical system using the beam splitter 52. Therefore, a high-magnification image and a low-magnification image may be simultaneously acquired, and a first combined image obtained by combining the high-magnification images and a second combined image obtained by combining the low-magnification images may be acquired.

[0170] In step SI3, it is determined whether or not to perform ghost display. For example, if the user selected "display ghost" during measurement setup, the determination in step SI3 is YES, and the process proceeds to step SI4, where the control unit 3d displays the search area as a ghost on the display unit 4 to guide the user to place the workpiece W in an appropriate position on the stage 21. Ghost display refers to superimposing the search area, which was set in advance during measurement setup, on the planar image; for example, the search area is displayed lighter than the planar image so as not to interfere with recognition of the planar image. If the user selected "do not display ghost" during measurement setup, the determination in step SI3 is NO, and the process proceeds to step SI5. Ghost display may also be performed on the combined image, the overhead image, etc.

[0171] In step SI5, it is determined whether or not a search area is to be specified. That is, if the user specifies a search area for a feature pattern during measurement, the determination in step SI5 is YES and the process proceeds to step SI6. However, if the user does not specify a search area, the process proceeds to step SI7. The search area is specified by the user enclosing a specific area using the mouse 6 or the like on any image, such as a planar image, a connected image, or a bird's-eye view image. At this time, for example, if an overhead image acquired by capturing an image of the entire workpiece W using the imaging unit 50 (or the stage cameras 46, 47, or the front camera 48) is displayed on the display unit 4, the user can specify a search area on the overhead image displayed on the display unit 4. Note that using the imaging unit 50 or the stage cameras 46, 47, which capture images from directly above, rather than the front camera 48, which captures images from an oblique angle, makes it easier to specify the search range.

[0172] In step SI7, it is determined whether or not the measurement start button 2a has been pressed. Steps SI2 to SI7 are repeated until the measurement start button 2a is pressed, and when the measurement start button 2a is pressed, the process proceeds to step SI8. In step SI8, it is determined whether or not to display an overhead image on the display unit 4. If the user selected "display overhead image" during measurement setup, the process returns YES in step SI8 and proceeds to step SI9, where the control unit 3d displays the overhead image captured by the front camera 48 on the display unit 4. If the user selected "do not display overhead image" during measurement setup, the process returns NO in step SI8 and proceeds to step SI10.

[0173] In step SI10, it is determined whether or not a color image is to be generated. If the user selected "Generate color image" when setting up the measurement, the determination in step SI10 is YES and the process proceeds to step SI12. In step SI12, a color image of the workpiece W (a workpiece image newly generated for measurement) is generated by processing similar to step SC5 shown in FIG. 16. On the other hand, if the user selected "Do not generate color image" when setting up the measurement, the determination in step SI10 is NO and the process proceeds to step SI11. In step SI11, a grayscale image of the workpiece W (a workpiece image newly generated for measurement) is generated by processing similar to step SC4 shown in FIG. 16.

[0174] Next, the process proceeds to step SI13 in FIG. 29B. In step SI13, a target image for pattern search is acquired. For example, the control unit 3d can acquire a color image of the workpiece W newly generated for measurement in step SI11, or a grayscale image of the workpiece W newly generated for measurement in step SI12, as the target image for pattern search. After acquiring the target image for pattern search, the process proceeds to step SI14, where the control unit 3d identifies the position and orientation of the feature pattern from the workpiece image newly generated for measurement. At this time, if a search area was specified by the user in step SI6, the position and orientation of the feature pattern is identified by narrowing the search area to the specified search area. This improves processing speed.

[0175] Furthermore, when the concatenated image is used as the workpiece image, the control unit 3d controls the XY-direction drive unit 23 to move the stage 21 in the X and Y directions until the workpiece W falls within the field of view of the imaging unit 50. Once the workpiece W falls within the field of view, the imaging unit 50 captures the workpiece W that has fallen within the field of view. The stage 21 is then moved in the X and Y directions so that another portion of the workpiece W falls within the field of view, and the imaging unit 50 captures the other portion of the workpiece W that has fallen within the field of view. The concatenated image obtained by concatenating the multiple images acquired in this manner becomes the workpiece image, and the position and orientation of the feature pattern are identified from the concatenated image. In this case, if a search area is specified by the user, the position and orientation of the feature pattern are identified by narrowing the search area to the specified search area.

[0176] The process then proceeds to step SI15. In step SI15, the control unit 3d determines the first and second contact target positions P1 and P2 for measurement based on the position and orientation of the workpiece W determined in step SI14, the relative positional relationship of the first and second contact target positions P1 and P2 with respect to the feature pattern, and the fixed positional relationship between the imaging unit 50 and the touch probe 80. For example, if at least one of the position or orientation of the workpiece W based on the workpiece image newly generated during measurement differs from the position or orientation of the workpiece W used during measurement setup, the position or orientation of the workpiece W can be corrected based on the position and orientation of the workpiece W determined in step SI14. The position is determined by the X-coordinate and the Y-coordinate, and the orientation is determined by the rotation angle around the X-axis and the rotation angle around the Y-axis. Correcting the position can be called position correction, and correcting the orientation can be called orientation correction, but these may be collectively referred to as position correction.

[0177] During position correction, by using the relative positional relationship of the first and second contact target positions P1, P2 with respect to the feature pattern, the first and second contact target positions P1, P2 can be identified at the same positions as during measurement setting even after correction.

[0178] The control unit 3d can also perform a pattern search on a workpiece image newly generated for measurement by the imaging unit 50 to identify edge measurement elements, extract edges from the identified edge measurement elements, and identify the first and second contact target positions P1 and P2 based on the extracted edges. The third and fourth contact target positions P3 and P4 shown in FIG. 21 can also be identified in a similar manner. Because the fourth contact target position P4 is located on the slope S3, the fourth contact target position P4 can be identified using the inclination angle α of the slope S3. Knowing the inclination angle α allows the normal direction of the slope S3 to be estimated. This allows the fourth contact target position P4 to be identified as the position where the touch probe 80 is to contact the slope S3 of the workpiece W from the normal direction of the slope S3.

[0179] After the contact target position is identified, the process proceeds to step SI16. In step SI16, if there are multiple measurement points, the order of the measurement points is determined.

[0180] Steps SI17 to SI20 are the same as steps SC7 to SC10 in the flowchart shown in Fig. 16. For example, when image measurement is performed in step SI18, measurement is performed only within the measurement range accepted by the accepting unit 3e, thereby improving the measurement speed.

[0181] Furthermore, for example, in step SI19, the control unit 3d controls the XY-direction drive unit 23 so that the touch probe 80 contacts the side surface of the workpiece W, based on the first contact target position P1 for measurement specified in step SI15. The control unit 3d also controls the Z-direction drive unit 25 so that the touch probe 80 contacts the top surface of the workpiece W, based on the second contact target position P2 for measurement specified in step SI15. At this time, the touch probe 80 is moved relatively along the scan line set during measurement setup, and the number of measurement points, start margin, start position, end position, approach direction, etc. are reflected.

[0182] When moving the touch probe 80 relative to the workpiece W, the control unit 3d controls the Z-direction drive unit 25 and the XY-direction drive unit 23 so that the touch probe moves in the approach direction set in Fig. 23. At this time, the relative movement speed is set to a first speed until the touch probe 80 comes into contact with the workpiece W, and when contact is detected, the touch probe 80 is returned a predetermined distance from the contact position, and then moved relatively to the workpiece W at a second speed slower than the first speed until the touch probe 80 comes into contact with the workpiece W, and the measurement result is output based on the position of contact at the second speed. This enables precise measurement.

[0183] Furthermore, when the touch probe 80 is brought into contact with the slope of the workpiece W, the touch probe 80 is brought close to the slope of the workpiece W at a first speed, and when the distance between the touch probe 80 and the slope of the workpiece W reaches a predetermined distance, the relative movement speed is set to a second speed. Then, a measurement result is output based on the position where the touch probe 80 made contact at the second speed.

[0184] Furthermore, in step S1, the control unit 3d reads out the correspondence between the position of the measurement element on the workpiece image, the shape type or size of the measurement element, and the position and number of the contact target positions of the touch probe 80 relative to the measurement element. Therefore, the control unit 3d can identify multiple contact target positions for the touch probe 80 based on the position of the measurement element on the workpiece image, the shape type or size of the measurement element, and the correspondence, and control the XY-direction drive unit 23 and the Z-direction drive unit 25 so that the touch probe 80 moves sequentially to the identified multiple contact target positions. In this way, multiple contact target positions for the touch probe 80 are automatically identified based on information at the time of measurement setup, and the XY-direction drive unit 23 and the Z-direction drive unit 25 are automatically controlled, simplifying the measurement work by the user.

[0185] In step SI20, non-contact height measurement is performed using the non-contact displacement meter 70. At this time, height measurement may be performed multiple times using the non-contact displacement meter 70, and an averaging process may be performed to average the multiple height measurement values ​​obtained. A specific example will be described based on the flowchart shown in FIG.

[0186] In step SJ1 after starting, the control unit 3d drives the Z-direction drive unit 25 to move the measurement execution unit 24 so that the focus of the non-contact displacement meter 70 is on the measurement location. In step SJ2, it is determined whether a measurement value can be read out by the non-contact displacement meter 70. If a measurement value cannot be read out, the process proceeds to step SJ3 to perform a rough search, that is, to move the measurement execution unit 24 to a position where the measurement value can be read out by the non-contact displacement meter 70. If a measurement value can be read out in step SJ2, the process proceeds to step SJ3 to perform a fine search. In the fine search, the measurement execution unit 24 is moved and focus adjusted so that the measurement value of the non-contact displacement meter 70 becomes approximately zero.

[0187] In step SJ5, it is determined whether the measurement value of the non-contact displacement meter 70 is smaller than the convergence judgment value. The convergence judgment value can be set to, for example, approximately 0.2 mm, but is not limited to this. If the determination in step SJ5 is NO and the measurement value of the non-contact displacement meter 70 is equal to or greater than the convergence judgment value, proceed to step SJ6 to determine whether the number of feedback iterations has been exceeded. The number of feedback iterations can be set to, for example, five, but is not limited to this. If the number of feedback iterations has not been exceeded, proceed to step SJ4. If the number of feedback iterations has been exceeded, proceed to step SJ7. In step SJ7, it is determined whether automatic adjustment is OFF. If automatic adjustment is ON, proceed to step SJ8 to determine whether a second peak has been acquired in the received light waveform of the non-contact displacement meter 70. If a second peak has been acquired, proceed to step SJ11, where the workpiece W is estimated to be a transparent body and the transparent body mode is selected. If a second peak has not been acquired, proceed to step SJ12, where the workpiece W is estimated to be a non-transparent body and the non-transparent body mode is selected.

[0188] Then, proceed to step SJ13. In step SJ13, the diameter of the regular lobe curve used in scanning when averaging the measurement values ​​is set to the small diameter. In step SJ14, the control unit 3d controls the stage 21 so that the focus of the non-contact displacement meter 70 is the trajectory of the regular lobe curve on the surface of the workpiece W. The figure created by the regular lobe curve during averaging is a figure that is point-symmetric and line-symmetric. The center of the regular lobe curve is set to be the point to be measured. The diameter of the regular lobe curve may be selectable by the user from pre-defined values ​​such as 0.25 mm, 0.5 mm, 1 mm, etc.

[0189] The user may be allowed to select whether or not to perform the averaging process. For example, a configuration may be adopted in which a user interface accepts a selection of whether or not to perform the averaging process from the user, and the averaging process is performed when the user selects to perform the averaging process, and the averaging process is not performed when the user selects not to perform the averaging process.

[0190] In step SJ14, it is further determined whether the measurement value variance during scanning of the square lobe curve is smaller than the automatic adjustment threshold. The automatic adjustment threshold can be set to, for example, about 0.005 mm, but is not limited to this. If the measurement value variance during scanning of the square lobe curve is equal to or greater than the automatic adjustment threshold, the square lobe curve is turned ON (averaging processing is performed). However, if the measurement value variance during scanning of the square lobe curve is smaller than the automatic adjustment threshold, high-precision measurement values ​​can be obtained without performing averaging processing, so the square lobe curve is turned OFF (averaging processing is not performed).

[0191] Next, the process proceeds to step SJ17, where measurements are performed, and then to step SJ18, where the dimensions are calculated. When performing measurements, the square lobe curve is scanned and the measured values ​​at multiple points are saved. When calculating dimensions, the measured values ​​at multiple points are averaged to determine the output value.

[0192] After performing the measurement as described above, the process proceeds to step SI21 in Fig. 29B. In step SI21, it is determined whether or not measurement of all measurement points has been completed. If measurement points remain, the process proceeds to step SI17, whereas if measurement of all measurement points has been completed, the process proceeds to steps SI22 and SI23. Steps SI22 and SI23 superimpose the measurement results on the workpiece image, similar to steps SC12 and SC13 in the flowchart shown in Fig. 16.

[0193] When performing measurement using the non-contact displacement meter 70, the control unit 3d may execute an extraction process to extract, from the workpiece image, an edge measurement element to be used in image measurement. If the edge measurement element is successfully extracted in this extraction process, the control unit 3d executes image measurement and height measurement using the non-contact displacement meter 70.

[0194] Furthermore, when performing measurement using the non-contact displacement meter 70, the control unit 3d may move the stage 21 in a direction perpendicular to the imaging axis of the imaging unit 50 so that the focus of the non-contact displacement meter 70 is aligned with the measurement location, and then perform height measurement using the non-contact displacement meter 70 to determine whether a height measurement value is obtained. If a height measurement value is not obtained, the non-contact displacement meter 70 may be moved along the imaging axis by the Z-direction driving unit 25 until a height measurement value is obtained. Therefore, since the non-contact displacement meter 70 is moved in the imaging axis direction together with the imaging unit 50 using the Z-direction driving unit 25 that adjusts the focal position of the imaging unit 50, the measurement time can be shortened when performing high-precision height measurement using the non-contact displacement meter 70.

[0195] (indicator) As shown in FIG. 6, the device main body 2 is provided with an indicator 2c. The indicator 2c is provided on the surface of the device main body 2 facing the user, and is controlled by the control unit 3. The indicator 2c indicates the measurement result and is composed of, for example, a light-emitting unit, a display unit, etc. The control unit 3 controls the indicator 2c so that it displays differently when the measurement result satisfies a predetermined condition and when it does not. The predetermined condition is set in advance by the user and stored in the memory unit 7, etc. For example, if the measurement result is equal to or greater than a certain value, it is displayed in red, etc., indicating a defective product, and if the measurement result is less than the certain value, it is displayed in green, etc., indicating a non-defective product.

[0196] (Variation) 31 shows Modification 1 in which the high-magnification side imaging element 55 and the low-magnification side imaging element 56 of the imaging unit 50 are three-channel imaging elements. That is, since the high-magnification side imaging element 55 and the low-magnification side imaging element 56 are configured with three-channel imaging elements consisting of RGB, a color workpiece image can be generated by emitting only one color of white light from the ring illumination 45.

[0197] In Modification 1, the control unit 3 includes a conversion unit 3h. The conversion unit 3h converts the color workpiece image generated by the imaging unit 50 into a grayscale workpiece image, and this conversion can be performed by a conventionally known method. The image measurement unit 3a is configured to measure the dimensions of the workpiece W based on the grayscale workpiece image converted by the conversion unit 3h.

[0198] Furthermore, the color information generating unit 3f generates color information of the workpiece W based on the color workpiece image generated by the imaging unit 50. The control unit 3d generates a color image by adding the color information of the workpiece W generated by the color information generating unit 3f to the grayscale workpiece image converted by the conversion unit 3h. This makes it possible to display on the display unit 4 a color image by adding the color information of the workpiece generated by the color information generating unit 3f to the grayscale workpiece image converted by the conversion unit 3h, and to superimpose the results of the dimension measurement by the image measuring unit 3a on the color image.

[0199] Next, Modification 2 shown in Fig. 32 will be described. Modification 2 has a first imaging unit 50A which has a single-channel imaging element and receives detection light to generate a grayscale workpiece image, and a second imaging unit 50B which has a three-channel imaging element consisting of RGB and receives detection light to generate a color workpiece image. The first imaging unit 50A is composed of a single-channel high-magnification side imaging element 55 and a low-magnification side imaging element 56. The image measuring unit 3a is configured to measure the dimensions of the workpiece W based on the workpiece image generated by the first imaging unit 50A.

[0200] The color information generating unit 3f generates color information of the workpiece W based on the workpiece image generated by the second imaging unit 50B. The control unit 3d generates a color image by adding the color information of the workpiece W generated by the color information generating unit 3f to the grayscale workpiece image generated by the first imaging unit 50A. The display unit 4 displays the color image generated by the control unit 3d, and also displays the results of the dimension measurement by the image measuring unit 3a superimposed on the color image.

[0201] The above-described embodiments are merely examples in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0202] As described above, the present disclosure can be used when measuring the three-dimensional coordinates of a workpiece placed on a stage. [Explanation of symbols]

[0203] 1. Image measuring device 3a Image measurement section 3b Coordinate measurement section 3c Displacement measurement section 3D control unit 3g settings section 4 Display 7 Memory section 21 Stages 23 XY direction drive unit 25 Z-direction drive unit 30 Transmitted illumination (light projector) 40 Coaxial epi-illumination (light projection part) 45 Ring lighting (light projector) 50 Imaging unit 80 Touch Probe 100 Changer mechanism 101 Stylus holder 101a, 101b, 101c Notch 102 Arm section 103 Changer rotation drive unit (rotating unit) 104 Changer feed drive unit (slider unit)

Claims

1. a stage on which a workpiece is placed; a base that movably supports the stage; a light projecting unit provided on the base and configured to project detection light onto the workpiece on the stage; an imaging unit that receives the detection light irradiated by the light projecting unit and generates a workpiece image; a support part connected to the base and supporting the imaging part above the stage; a movable section provided on the support section and movable along an imaging axis of the imaging section; a housing fixed to the movable part and to which a stylus having a contact part that comes into contact with a workpiece is detachably attached; a stylus holder for holding one or more styli; an arm portion attached to the support portion, supporting the stylus holding portion, and moving the stylus held by the stylus holding portion between an attachable position at which the stylus can be attached to the housing and a retracted position at which the stylus is retracted from the attachable position; a control unit that controls the arm unit to move the stylus to the attachable position and the movable unit to lower the housing, thereby attaching the stylus to the housing; An image measuring device comprising:

2. 2. The image measuring device according to claim 1, An image measuring device, characterized in that focus adjustment of the imaging unit is performed by moving the movable unit in a direction along the imaging axis.

3. 2. The image measuring device according to claim 1, The arm portion moves the stylus in a direction perpendicular to the imaging axis.

4. 4. The image measuring device according to claim 3, the stylus holder can be disposed on the tip side of the arm, a rotation unit connected to a base end side of the arm unit and configured to rotate the stylus holding unit around a rotation axis parallel to the imaging axis is attached to the support unit; The image measuring device is characterized in that the control unit controls the rotation unit so that the stylus is placed at the attachable position.

5. 5. The image measuring device according to claim 4, an image measuring device, characterized in that the rotating part is attached to the support part so that the rotation axis is positioned between the stylus in the attachable position and the stylus in the retracted position;

6. 5. The image measuring device according to claim 4, a slider portion that moves the stylus holder in the axial direction of the arm portion; The control unit controls the slider unit so that the stylus is placed at the attachable position.

7. 7. The image measuring device according to claim 6, The control unit controls the slider unit so that the stylus holding unit in the retracted position is positioned closer to the base end of the arm unit than the stylus holding unit in the attachable position.

8. 8. The image measuring device according to claim 7, an arm portion configured to rotate when the stylus is in the retracted position and to move the stylus holder toward the tip of the arm portion; and an image measuring device configured to move the stylus from the retracted position to the attachable position when the stylus is in the retracted position and to move the stylus holder toward the tip of the arm portion.

9. 8. The image measuring device according to claim 7, the stylus holder has at least two or more notched portions for holding different types of styluses; The control unit controls the slider unit so that the stylus held in a desired one of the two or more cutout portions is positioned at the attachable position.

10. 2. The image measuring device according to claim 1, The image measuring device according to claim 1, wherein the support portion includes a canopy portion that covers at least a portion of the upper side of the stylus holder when the stylus holder is in the retracted position.

Images