JP2016200399A - Surface shape measurement device and surface shape measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface shape measurement device and a surface shape measurement method that allow a single measurement device to implement a measurement from an entire shape of a workpiece to surface roughness thereof.SOLUTION: A surface shape measurement device 100 comprises: a contactless sensor 122; and a surface shape sensor unit 120 that includes a first drive unit 124 causing the contactless sensor 122 to move in a direction of a measurement axial line M, and a second drive unit 126 causing the first drive unit to move in the same direction. The first drive unit 124 includes a piezo-actuator that has a first movable range broader than a detection limit of the contactless sensor 122, and the second drive unit 126 includes a rectilinear movement table that has a second movable range broader than the first movable range. A surface shape measurement of a workpiece W1 is implemented while causing two actuators to move the contactless sensor in the direction of the measurement axial line M so that a measuring point D of the contactless sensor 122 remains located within the detection limit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surface shape measuring device and a surface shape measuring method.

  As a surface shape measuring device, a contact type using a stylus (Patent Document 1), a non-contact type using a laser beam (Patent Document 2), and the like are known. In these surface shape measuring devices, in general, devices for measuring irregularities on the order of millimeters have a wide measurement range, but do not have the resolution on the order of nanometers required for measuring surface roughness. An apparatus for measuring surface roughness has a high measurement resolution on the order of nanometers, but does not have a wide measurement range on the order of millimeters. Therefore, for example, when measuring both the overall shape and the surface roughness of a member having a step on the order of millimeters, the overall shape and the fine surface roughness are measured separately using a plurality of separate measuring devices. There was a need.

Japanese Unexamined Patent Publication No. 2000-97691 JP 2012-2573 A

  However, in the method of measuring with a plurality of different measuring devices, it is necessary to set the object to be measured many times on the device, and it is also necessary to align the data measured separately, which takes a lot of time for the measurement. It took time and effort.

  In view of the above problems, an object of the present invention is to provide a surface shape measuring device and a surface shape measuring method that enable measurement from the entire shape of the object to be measured to the surface roughness with a single measuring device. .

That is, the present invention
A device base;
A stage set at the base of the apparatus and supporting the object to be measured;
A surface shape sensor unit for measuring the surface shape of an object to be measured which is set in the apparatus base and supported by the stage;
A moving mechanism for moving the stage relative to the surface shape sensor unit;
A surface shape measuring device comprising:
The surface shape sensor unit is
A detection limit having a predetermined width in the direction of a predetermined measurement axis, and a point on the surface of the object that intersects the measurement axis as a measurement point, the measurement point within the detection limit in the direction of the measurement axis A first sensor for measuring the position;
A first actuator for holding the first sensor, having a first movable range having a predetermined width in the direction of the measurement axis that is wider than the width of the detection limit, and the measurement point is within the detection limit; A first actuator for moving the first sensor in the direction of the measurement axis within the first movable range so as to be positioned at
A second sensor for measuring a moving distance of the first sensor by the first actuator;
A second actuator that holds the first actuator and has a second movable range having a predetermined width in the direction of the measurement axis that is wider than the width of the first movable range; The first actuator is moved in the direction of the measurement axis within the second movable range so that the first sensor can be moved within the first movable range to position the measurement point within the detection limit. A second actuator,
A third sensor for measuring a movement distance of the first actuator by the second actuator,
The first stage when the stage and the first sensor are moved relative to each other so that the measurement point of the first sensor moves relatively on the surface of the object to be measured by the moving mechanism. Provided is a surface shape measuring device configured to measure the surface shape of an object to be measured based on output values of second and third sensors.

  In the surface shape measuring apparatus, the first sensor that directly measures the surface of the object to be measured includes the first actuator having the first movable range and the second actuator having the second movable range wider than the first movable range. By displacing in the direction of the measurement axis, the range in the direction of the measurement axis that can be measured by the first sensor can be greatly expanded. As a result, the surface shape can be measured within the wide range of the first and second movable ranges with the measurement resolution of the first sensor, so that it has been necessary to measure with a plurality of separate measuring devices in the past. Even for an object to be measured having a step or the like, the surface shape can be measured with one measuring device.

  Preferably, the first actuator has a measurement reference point located within the detection limit, and the measurement point becomes the measurement reference point during the surface shape measurement of the object to be measured by the surface shape sensor unit. The first sensor can be continuously moved so as to approach.

  With such a configuration, for example, by setting the measurement reference point near the center of the detection limit, it is possible to reduce the possibility that the measurement point falls outside the detection limit.

  Preferably, the second actuator may be configured not to move the first actuator during the surface shape measurement of the object to be measured by the surface shape sensor unit.

  Specifically, the width of the detection limit is 1 micrometer or more and less than 0.1 millimeter, the width of the first movable range is 0.1 millimeter or more and less than 2 millimeters, and the width of the second movable range is It can be 10 millimeters or more.

  More specifically, the first actuator is a piezo actuator, the second actuator is a motor driven linear motion table, the second sensor is a strain gauge, and the third sensor is a linear scale. Can be.

  More specifically, the first sensor can be an optical non-contact sensor.

  Preferably, the moving means may have a horizontal plane moving mechanism for moving the stage in a plane perpendicular to the measurement axis.

  Alternatively, the moving means includes a rotation mechanism that rotates the stage around a rotation axis perpendicular to the measurement axis, and a vertical movement mechanism that moves the surface shape sensor unit in a direction parallel to the rotation axis. Can have.

The present invention also provides
A first sensor that has a detection limit with a predetermined width in the direction of a predetermined measurement axis, and that measures a position in the direction of the measurement axis of a measurement point that is a point on the object surface that intersects the measurement axis; A first actuator that holds the first sensor and moves the first sensor in the direction of the measurement axis; a second sensor that measures a moving distance of the first sensor by the first actuator; and the first actuator A surface shape sensor unit comprising: a second actuator that moves the first actuator in the direction of the measurement axis while holding the third sensor; and a third sensor that measures a movement distance of the first actuator by the second actuator, A surface shape measuring method for measuring a surface shape of an object supported on a stage,
Relatively moving the stage and the surface shape sensor unit by a moving mechanism so that the measurement point of the first sensor is positioned at an arbitrary measurement start point on the surface of the object to be measured;
Moving the first actuator and the first sensor in the direction of the measurement axis by the second actuator so that the measurement point is within the detection limit;
Relatively moving the stage and the surface shape sensor unit by the moving mechanism so that the measurement point relatively moves on the surface of the object to be measured;
During the step of relatively moving the stage and the surface shape sensor unit, the first actuator moves the first sensor in the direction of the measurement axis so that the measurement point is maintained within the detection limit. Step to move with,
Reading the output values of the first to third sensors during the step of relatively moving the stage and the surface shape sensor unit;
The stage by the moving mechanism when measuring a surface where the moving distance of the first sensor required to maintain the measuring point within the detection limit exceeds the movable range of the first actuator And the surface shape sensor unit are temporarily stopped, and the first actuator and the first sensor are moved along the measurement axis by the second actuator so that the measurement point is located within the detection limit. Moving in the direction,
A surface shape measuring method is provided.

  By this method, it is possible to measure the surface shape within the wide first and second movable ranges of the first and second actuators with the measurement resolution of the first sensor.

Preferably, the first actuator has a measurement reference point located within the detection limit,
The step of moving the first sensor in the direction of the measurement axis includes the step of continuously moving the first sensor in the direction of the measurement axis by the first actuator so that the measurement point approaches the measurement reference point. Can be.

More preferably,
The moving means has a rotation mechanism for rotating the stage around a rotation axis perpendicular to the measurement axis, and a vertical movement mechanism for moving the surface shape sensor unit in a direction parallel to the rotation axis. , The object to be measured is a member having a cylindrical surface,
The step of relatively moving the stage and the surface shape sensor unit is a step of rotating the stage by the rotation mechanism so that the measurement point moves on the cylindrical surface of the object to be measured. Yes,
Based on the output values of the first to third sensors, at least one of the diameter and the roundness of the object to be measured can be obtained.

  Hereinafter, embodiments of a surface shape measuring apparatus and a surface shape measuring method according to the present invention will be described with reference to the accompanying drawings.

It is a front view of the surface shape measuring apparatus which concerns on the 1st Embodiment of this invention. It is a side view of the surface shape measuring unit of the surface shape measuring apparatus of FIG. It is a figure which shows the surface shape data measured by the surface shape measuring apparatus of FIG. It is a front view of the surface shape measuring apparatus which concerns on the 2nd Embodiment of this invention.

  As shown in FIGS. 1 and 2, the surface shape measuring apparatus 100 according to an embodiment of the present invention is moved by an apparatus base 110, a horizontal plane moving mechanism 112 fixed to the apparatus base 110, and a horizontal plane moving mechanism 112. A stage 114 configured to support the workpiece W1, a vertical coarse motion table 116 fixed to the apparatus base 110, and a surface shape sensor unit 120 held by the vertical coarse motion table 116.

  The surface shape sensor unit 120 includes an optical non-contact sensor (first sensor) 122 that measures the position of the object surface by irradiating the object surface with laser light and receiving reflected light from the object surface. The first drive unit 124 that holds the contact sensor 122, and the second drive unit 126 that holds the first drive unit 124 and is fixed to the vertical coarse movement table 116.

  The non-contact sensor 122 is adapted to measure the position of the object surface in the direction of the measurement axis M extending in the vertical direction and has a detection limit with a width of approximately 10 micrometers in the direction of the measurement axis M. The relative distance of the object surface from the measurement reference point set at the limit center position is measured. The measurement resolution is about 10 picometers. The measurement reference point can be set at an arbitrary position on the measurement axis M.

  The first drive unit 124 includes a piezo actuator (first actuator) that moves the non-contact sensor 122 in the direction of the measurement axis M and a strain sensor (second sensor) that measures the amount of displacement of the piezo actuator. The piezo actuator has a movable range with a width of approximately 1 millimeter in the direction of the measuring axis M. The positioning resolution is approximately 20 nanometers. Accordingly, the first driving unit 124 can position the non-contact sensor 122 within a range of 1 millimeter with a resolution of 20 nanometers.

  The second drive unit 126 includes a motor-driven linear motion table (second actuator) that moves the first drive unit 124 in the direction of the measurement axis M, and a linear scale (third sensor) that measures the movement distance of the linear motion table. have. The linear motion table has a movable range with a width of approximately 50 millimeters in the direction of the measuring axis M. The positioning resolution is approximately 50 nanometers. Therefore, the second driving unit 126 can position the first driving unit 124 and the non-contact sensor 122 held by the first driving unit 124 within a range of 50 millimeters with a resolution of 50 nanometers.

  A method for measuring the surface shape of the workpiece W1 having the surface as shown in FIG. 3a by the surface shape measuring apparatus 100 will be described below. When the measurement of the surface shape of the object to be measured W1 is started by the surface shape measuring apparatus 100, first, the object to be measured W1 to be measured is placed on the stage 114. Next, the stage 114 is moved in the horizontal direction by the horizontal plane moving mechanism 112 so that the measurement start point P1 on the measurement object W1 is on the measurement axis M of the non-contact sensor 122, and the measurement object W1 is moved. The measurement start point P1 and the measurement point D of the non-contact sensor 122 are matched. Further, the surface shape sensor unit 120 is moved in the vertical direction by the vertical coarse movement table 116 so that the measurement point D is within or near the measurement limit of the non-contact sensor 122. And the non-contact sensor 122 is moved with the 1st drive part 124 with the linear motion table of the 2nd drive part 126 of the surface shape sensor unit 120, and the measurement point D and a measurement reference point correspond.

  Next, the object to be measured W1 placed on the stage 114 is moved at a constant speed in the horizontal direction with respect to the surface shape sensor unit 120 by the horizontal plane moving mechanism 112. At this time, the measurement point D moves on the surface of the workpiece W1. The non-contact sensor 122 continuously measures the surface position of the workpiece W1 at the measurement point D in synchronization with the movement of the stage 114. Based on the output value of the non-contact sensor 122, the piezo actuator of the first drive unit 124 is not moved so that the measurement point D approaches the measurement reference point when there is a difference between the measurement point D and the measurement reference point. The contact sensor 122 is moved. That is, the piezo actuator moves the non-contact sensor 122 so as to keep the distance between the non-contact sensor 122 and the measurement surface constant. At this time, the linear motion table of the second drive unit 126 does not move. When the measurement point D reaches the measurement end point P2, the measurement is temporarily ended.

  If there is a step S having a size exceeding the movable range of the first drive unit 124 between the surfaces on which the surface shape is measured, the surface shape measurement is temporarily stopped, and the re-measurement start point P3 beyond the step S is set. At the position, the non-contact sensor 122 is moved together with the first drive unit 124 by the linear motion table of the second drive unit 126, and the measurement point D and the measurement reference point are aligned again. Thereafter, as described above, the object to be measured W1 placed on the stage 114 by the horizontal plane moving mechanism 112 is moved from the remeasurement start point P3 while moving at a constant speed in the horizontal direction with respect to the surface shape sensor unit 120. The surface shape is measured up to the measurement end point P4.

  When the surface shape measuring apparatus 100 measures the surface of the workpiece W1 shown in FIG. 3a, the output values of the non-contact sensor 122, the strain sensor of the first driving unit 124, and the linear scale of the second driving unit 126 are measured. Are shown in FIGS. 3b-3d, respectively. Since the piezo actuator does not have a high-speed response that can follow the fine unevenness of the surface, the non-contact sensor 122 is moved along the surface undulation that changes more slowly than the unevenness. Therefore, the non-contact sensor 122 does not detect surface waviness and detects only fine surface roughness information (FIG. 3b). On the other hand, the strain sensor which measured the moving distance of the piezo actuator does not detect the fine uneven shape of the surface, but only the surface undulation (FIG. 3c). Since the linear motion table does not move while measuring the surface shape from the measurement start point P1 to the measurement end point P2, the output value of the linear scale for measuring the movement distance of the linear motion table is constant during this period. (FIG. 3d). There is a large step S between the measurement end point P2 and the re-measurement start point P3. Before and after the step S, the non-contact sensor 122 is non-contacted so that the measurement point D coincides with the measurement reference point by the linear motion table. Since the contact sensor 122 is moved together with the first drive unit 124, the output value of the linear scale is increased by the height of the step S at the position of the remeasurement start point P3. In the output value from the non-contact sensor 122 from the remeasurement start point P3 to the remeasurement end point P4, the height fluctuation corresponding to the step S does not appear (FIG. 3b). Similarly, the height fluctuation corresponding to the step S does not appear in the output value of the strain sensor (FIG. 3c). When the output values of the non-contact sensor 122, the strain sensor, and the linear scale thus measured are added, the result is as shown in FIG. 3e, which is the result of measuring the surface shape of the workpiece W1. By this measurement, the surface roughness can be obtained by the nanometer order measurement, and at the same time, the shape of the millimeter order surface can be obtained. Note that the vertical axis scale of each graph in FIG. 3 is different in order to emphasize each data. For example, FIG. 3b is a nanometer-order scale, and FIG. 3d is a millimeter-order scale. FIG. 3e shows the surface shape with emphasis and the vertical axis scale is not constant. Furthermore, if the position of the stage 114 is also measured, the plate thickness of each part of the workpiece W1 can be measured.

  In the above embodiment, during the measurement of the surface shape of the object to be measured W1, the linear motion table of the second drive unit 126 is not moved and is held at a fixed position. If the entire surface is tilted or changes slowly, the linear motion table can be moved simultaneously during measurement to continuously measure the surface shape without interruption. . However, the linear motion table having a large movable range width is not as fast as the piezo actuator, and it is necessary to move the combined weight of the non-contact sensor 122 and the piezo actuator. In a portion where the shape changes abruptly, such as the step S, it usually cannot follow and move.

  As shown in FIG. 4, the surface shape measuring apparatus 200 according to the second embodiment of the present invention is rotated and moved by an apparatus base 210, a rotation mechanism 212 fixed to the apparatus base 210, and the rotation mechanism 212. A stage 214 configured to support the workpiece W2, a vertical coarse motion table 216 held by the apparatus base 210, a radial coarse motion table 218 held by the vertical coarse motion table 216, and a radial coarse motion table. A surface shape sensor unit 220 held at 218.

  Similar to the surface shape sensor unit 120 of the surface shape measuring apparatus 100 according to the first embodiment, the surface shape sensor unit 220 irradiates the object surface with laser light and receives reflected light from the object surface. An optical non-contact sensor 222 (first sensor) that measures the position of the object surface, a first drive unit 224 that holds the non-contact sensor 222, a first drive unit 224, and a radial coarse motion table And a second driving unit 226 fixed to 218. The first drive unit 224 includes a piezoelectric actuator (first actuator) that moves the non-contact sensor 222 in the direction of the measurement axis M and a strain sensor (second sensor) that measures the displacement of the piezoelectric actuator. The second drive unit 226 includes a linear motion table (second actuator) that moves the first drive unit 224 in the direction of the measurement axis M, and a linear scale (third sensor) that measures the movement distance of the linear motion table. ing. Each sensor and actuator is the same as that of the surface shape measuring apparatus 100 according to the first embodiment. However, the surface shape sensor unit 220 in the surface shape measuring apparatus 200 is attached so that the measurement axis M is in a direction perpendicular to the rotation axis R of the stage 214, that is, in the horizontal direction.

  The workpiece W2 to be measured by the surface shape measuring apparatus 200 is a columnar or cylindrical member having a cylindrical outer peripheral surface or inner peripheral surface. When the surface shape measurement apparatus 200 starts to measure the surface shape of the object W2 to be measured, first, it is placed on the stage 214 so that the center axis of the object W2 to be measured coincides with the rotation axis R of the stage 214. To do. Next, the surface shape sensor unit 220 is moved in the vertical direction by the vertical coarse movement table 216 so that the measurement start point on the measurement object W2 is on the measurement axis M of the non-contact sensor 222, and the measurement target is measured. The measurement start point of the object W2 and the measurement point D of the non-contact sensor 222 are matched. Further, the surface shape sensor unit 220 is moved in the horizontal direction by the radial direction coarse motion table 218 so that the measurement point D is within or near the measurement limit of the non-contact sensor 222. Then, the non-contact sensor 222 is moved together with the first drive unit 224 on the linear motion table of the second drive unit 226 of the surface shape sensor unit 220 so that the measurement point D and the measurement reference point coincide with each other.

  Next, the workpiece W <b> 2 placed on the stage 214 is rotated at a constant speed around the rotation axis R with respect to the surface shape sensor unit 220 by the rotation mechanism 212. At this time, the measurement point D moves on the cylindrical surface of the workpiece W2. The non-contact sensor 222 continuously measures the surface position of the workpiece W2 at the measurement point D in synchronization with the rotation of the stage 214. Based on the output value of the non-contact sensor 222, the piezo actuator of the first drive unit 224 is non-contact so that the measurement point D approaches the measurement reference point when there is a difference between the measurement point D and the measurement reference point. The contact sensor 222 is moved. That is, the piezo actuator moves the non-contact sensor 222 so as to keep the distance between the non-contact sensor 222 and the measurement surface constant. At this time, the linear motion table of the second drive unit 226 does not move. When the measurement point D makes a round on the cylindrical surface, the measurement is finished.

  When measuring the cylindrical surface at another position in the vertical direction, the surface shape sensor unit 220 is moved in the vertical direction by the vertical coarse movement table 216 to the next measurement start point. At this time, if the previously measured radius of the cylindrical surface is different from the radius of the cylindrical surface to be measured next, the non-contact sensor 222 is moved together with the first drive unit 224 by the linear motion table of the second drive unit 226. The position is adjusted again so that the measurement point D coincides with the measurement reference point. Thereafter, as described above, the surface shape measurement is performed while rotating the workpiece W2 placed on the stage 214 by the rotation mechanism 212 at a constant speed around the rotation axis R with respect to the surface shape sensor unit 220. Like that. By performing such a measurement, the difference in radius between the cylindrical surfaces can be accurately measured.

  In the surface shape measuring apparatus 200, a reference gauge having a known diameter is measured prior to measurement of the workpiece W2, so that the output value of each sensor becomes zero at the position of the rotation axis R of the stage 214. By calibrating, the diameter of the cylindrical surface of the workpiece W2 can be accurately measured. In addition, since the laser emitting part and the light receiving part of the non-contact sensor 222 are formed to be elongated in the lower direction, the non-contact sensor 222 is inserted into the cylindrical member, and the inner peripheral surface of the cylindrical member is inserted. It is also possible to make a measurement.

  As described above, according to the surface shape measuring apparatuses 100 and 200 of the present invention, the surface shape of a surface having a height difference of millimeter order can be measured at a time with a measurement resolution of nanometer order. It becomes possible to measure the surface shape of an object to be measured that requires an apparatus with a single measuring apparatus.

  Specific numerical values indicating the performance of the sensors and actuators of the surface shape sensor units 120 and 220 shown in the above embodiment are merely examples, and may have other performance values. For example, the non-contact sensor 122, The detection limit of 222 (first sensor) is preferably 1 micrometer or more and less than 0.1 millimeter, and the resolution is preferably in the range of 1 picometer to 1 nanometer, and the piezoelectric actuator (first sensor) The movable range of the actuator) is preferably 0.1 mm or more and less than 2 mm, the movable range of the linear motion table (second actuator) is preferably 10 mm or more and less than 300 mm, and the strain sensor (second sensor) ) Resolution of 1 to 50 nanometers But is preferably 囲内, resolution of the linear scale (third sensor) is preferably in the range of 100 nm from 1 nanometer.

  The optical non-contact sensors 122 and 222 may use other sensors such as a stylus type contact sensor as long as the optical non-contact sensors 122 and 222 have performance similar to the above-described performance. The piezo actuator, strain sensor, linear motion table, and linear scale that constitute the first drive units 124 and 224 and the second drive units 126 and 226, respectively, should have the same performance as the above performance. Other actuators and sensors can be used.

  In the above-described embodiment, the non-contact sensors 122 and 222 have been described as point measuring sensors that measure the height of one point on the object surface. However, the detection elements are arranged in a line or a plane. It can also be a measurement sensor or a surface measurement sensor. For example, in the case of a line measurement sensor, the height at a line-shaped position on the object surface can be measured at the same time, and any one of the line-shaped points is used as the measurement point D in the above embodiment. By selecting, position control in the direction of the measurement axis M of the line measurement sensor can be performed. Alternatively, the measurement point D may be changed to another line-like point during measurement. The same applies to the surface measurement sensor.

Surface shape measuring device 100; device base 110; horizontal plane moving mechanism 112; stage 114; vertical coarse motion table 116; surface shape sensor unit 120; non-contact sensor (first sensor) 122; first drive unit 124; 126;
Surface shape measuring device 200; device base 210; rotating mechanism 212; stage 214; vertical coarse motion table 216; radial coarse motion table 218; surface shape sensor unit 220; non-contact sensor (first sensor) 222; 224; second drive unit 226;
Measurement object W1, W2; measurement axis M; measurement point D; measurement start point P1: measurement end point P2; remeasurement start point P3; remeasurement end point P4;

Claims (11)

A device base;
A stage set at the base of the apparatus and supporting the object to be measured;
A surface shape sensor unit for measuring the surface shape of an object to be measured which is set in the apparatus base and supported by the stage;
A moving mechanism for moving the stage relative to the surface shape sensor unit;
A surface shape measuring device comprising:
The surface shape sensor unit is
A detection limit having a predetermined width in the direction of a predetermined measurement axis, and a point on the surface of the object that intersects the measurement axis as a measurement point, the measurement point within the detection limit in the direction of the measurement axis A first sensor for measuring the position;
A first actuator for holding the first sensor, having a first movable range having a predetermined width in the direction of the measurement axis that is wider than the width of the detection limit, and the measurement point is within the detection limit; A first actuator for moving the first sensor in the direction of the measurement axis within the first movable range so as to be positioned at
A second sensor for measuring a moving distance of the first sensor by the first actuator;
A second actuator that holds the first actuator and has a second movable range having a predetermined width in the direction of the measurement axis that is wider than the width of the first movable range; The first actuator is moved in the direction of the measurement axis within the second movable range so that the first sensor can be moved within the first movable range to position the measurement point within the detection limit. A second actuator,
A third sensor for measuring a movement distance of the first actuator by the second actuator,
The first stage when the stage and the first sensor are moved relative to each other so that the measurement point of the first sensor moves relatively on the surface of the object to be measured by the moving mechanism. A surface shape measuring device configured to measure the surface shape of an object to be measured based on output values of the second and third sensors.   The first actuator has a measurement reference point located within the detection limit, and the measurement point approaches the measurement reference point during the surface shape measurement of the object to be measured by the surface shape sensor unit. The surface shape measuring apparatus according to claim 1, wherein the first sensor is continuously moved.   The surface shape measuring apparatus according to claim 1, wherein the second actuator is configured not to move the first actuator during the surface shape measurement of the object to be measured by the surface shape sensor unit.   The detection limit width is 1 micrometer or more and less than 0.1 millimeter, the first movable range width is 0.1 millimeter or more and less than 2 millimeters, and the second movable range width is 10 millimeters or more. The surface shape measuring device according to any one of claims 1 to 3.   The first actuator is a piezo actuator, the second actuator is a motor-driven linear motion table, the second sensor is a strain gauge, and the third sensor is a linear scale. Surface shape measuring device.   The surface shape measuring apparatus according to any one of claims 1 to 5, wherein the first sensor is an optical non-contact sensor.   The surface shape measuring apparatus according to claim 1, wherein the moving unit includes a horizontal plane moving mechanism that moves the stage in a plane perpendicular to the measurement axis.   The moving means includes a rotation mechanism that rotates the stage around a rotation axis perpendicular to the measurement axis, and a vertical movement mechanism that moves the surface shape sensor unit in a direction parallel to the rotation axis. The surface shape measuring apparatus as described in any one of Claims 1 thru | or 6. A first sensor that has a detection limit with a predetermined width in the direction of a predetermined measurement axis, and that measures a position in the direction of the measurement axis of a measurement point that is a point on the object surface that intersects the measurement axis; A first actuator that holds the first sensor and moves the first sensor in the direction of the measurement axis; a second sensor that measures a moving distance of the first sensor by the first actuator; and the first actuator A surface shape sensor unit comprising: a second actuator that moves the first actuator in the direction of the measurement axis while holding the third sensor; and a third sensor that measures a movement distance of the first actuator by the second actuator, A surface shape measuring method for measuring a surface shape of an object supported on a stage,
Relatively moving the stage and the surface shape sensor unit by a moving mechanism so that the measurement point of the first sensor is positioned at an arbitrary measurement start point on the surface of the object to be measured;
Moving the first actuator and the first sensor in the direction of the measurement axis by the second actuator so that the measurement point is within the detection limit;
Relatively moving the stage and the surface shape sensor unit by the moving mechanism so that the measurement point relatively moves on the surface of the object to be measured;
During the step of relatively moving the stage and the surface shape sensor unit, the first actuator moves the first sensor in the direction of the measurement axis so that the measurement point is maintained within the detection limit. Step to move with,
Reading the output values of the first to third sensors during the step of relatively moving the stage and the surface shape sensor unit;
The stage by the moving mechanism when measuring a surface where the moving distance of the first sensor required to maintain the measuring point within the detection limit exceeds the movable range of the first actuator And the surface shape sensor unit are temporarily stopped, and the first actuator and the first sensor are moved along the measurement axis by the second actuator so that the measurement point is located within the detection limit. Moving in the direction,
A surface shape measuring method. The first actuator has a measurement reference point located within the detection limit;
The step of moving the first sensor in the direction of the measurement axis includes the step of continuously moving the first sensor in the direction of the measurement axis by the first actuator so that the measurement point approaches the measurement reference point. The surface shape measuring method according to claim 9, wherein The moving means has a rotation mechanism for rotating the stage around a rotation axis perpendicular to the measurement axis, and a vertical movement mechanism for moving the surface shape sensor unit in a direction parallel to the rotation axis. , The object to be measured is a member having a cylindrical surface,
The step of relatively moving the stage and the surface shape sensor unit is a step of rotating the stage by the rotation mechanism so that the measurement point moves on the cylindrical surface of the object to be measured. Yes,
The surface shape measuring method according to claim 9 or 10, wherein at least one of a diameter and a roundness of the object to be measured is obtained based on output values of the first to third sensors.

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