JP2007114095A - Surface property measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface property measuring device for copy-measuring an inclined surface of an object under measurement with high accuracy. <P>SOLUTION: The surface of the object under measurement is copy-measured by a measurement part 210. The measurement part 210 comprises a stylus 211 having a contact part 212 at its end and a measurement force detection means for detecting measurement force in a stylus axis direction when the contact part 212 makes contact with the surface of the object. A movement mechanism relative-moves the measurement part 210 with respect to the surface of the object while keeping measurement force constant. The movement mechanism is equipped with a turning mechanism 400 for making the stylus 211 perpendicular to the surface of the object by turning the measurement part 210 with the contact part 212 used as a turning center. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

The present invention relates to a surface texture measuring device.
For example, the present invention relates to a surface property measuring apparatus that detects the surface of an object to be measured by a contact probe and measures the surface shape of the object to be measured.

Measuring devices that scan the surface of the object to be measured and measure surface properties such as the three-dimensional shape, roughness, and undulation of the object to be measured are known, for example, a roughness measuring machine, a contour shape measuring machine, a roundness measuring machine, A three-dimensional measuring machine is known. In such a measuring apparatus, a probe as a sensor for detecting the surface of the object to be measured is used (Patent Document 1).
FIG. 5 shows a configuration of the surface texture measuring apparatus 100 using the probe 200.
The surface texture measuring apparatus 100 includes a probe 200 and a three-dimensional drive mechanism 300 as a moving mechanism that moves the probe 200 along the surface S of the object to be measured three-dimensionally.

As shown in FIG. 6, the probe 200 includes a stylus 211 having a contact portion 212 at the tip, a stylus holder 213 that supports the stylus 211, and a vibration unit that constantly vibrates the stylus 211 at a natural frequency in the axial direction. 214 is an excitation-type contact probe including 214 and detection means 217 that detects a vibration change of the stylus 211 and outputs a detection signal.
The vibration means 214 includes a piezoelectric element 215 that is provided in the stylus holder 213 and vibrates the stylus 211, and an excitation circuit 216 that applies an output signal (such as a pulse or a sine wave signal) having a predetermined frequency to the piezoelectric element 215. It is configured.
The detection means 217 includes a piezoelectric element 218 that converts the vibration of the stylus 211 into a voltage, and a detection circuit 219 that detects a voltage from the piezoelectric element 218 and outputs a detection signal.

  As the three-dimensional drive mechanism 300, a mechanism including X, Y, and Z-direction slide mechanisms used in a conventional three-dimensional measuring apparatus is used. Each axis of the three-dimensional drive mechanism 300 is provided with a linear encoder that detects a drive amount.

In such a configuration, when the contact portion 212 is moved along the object surface S as shown in FIG. 7, the positional relationship between the contact portion 212 and the object surface S is shown in FIG. A change in the detection signal occurs as shown.
When the contact part 212 starts to contact the object surface S to be measured (B) from the state where the contact part 212 is free (A), and the contact part 212 contacts the object surface S to be measured with a predetermined measuring force (C). The vibration of the contact part 212 is constrained and the detection signal reaches a preset reference level.

  The measurement force refers to a force when the contact portion 212 is pressed against the measurement object surface S when the contact portion 212 is brought into contact with the measurement object surface S and the measurement object surface S is detected.

  When the contact portion 212 is moved along the surface to be measured S in a state where the contact portion 212 is pressed against the surface to be measured S so that the detection signal value becomes the reference level, and the detection signal reaches the reference level. The position information of the probe 200 is sampled from the X, Y, and Z axis slide amounts of the three-dimensional drive mechanism 300. By calculating the contact point between the contact portion 212 and the object surface S from the sampled position information of the probe 200, the shape of the object surface S can be known.

  Here, the way in which the detection signal is attenuated differs depending on the angle at which the contact portion 212 and the surface S of the object to be measured contact. That is, since the stylus 211 is vibrated so as to vibrate in the axial direction, when the contact portion 212 comes into contact with the surface S of the object to be measured from the axial direction of the stylus 211 (for example, A in FIG. 7), The degree to which the vibration of the stylus 211 is constrained differs from the case where the contact portion 212 abuts on the measurement object surface S in a direction shifted from the axial direction (for example, B in FIG. 7).

  Therefore, in the vibrating contact probe 200, the reference level of the detection signal is set on the premise that the object to be measured is contacted from the axial direction of the stylus 211. Therefore, when the contact portion 212 comes into contact with the workpiece surface S from the axial direction of the stylus 211, the vibrating contact probe 200 is moved so as to make the detection signal a reference level, and the measurement is performed with a constant measurement force. The object surface S can be scanned.

JP 2004-61322 A

However, depending on the inclination state of the surface of the object to be measured S, the contact portion 212 comes into contact with the surface of the object to be measured S not in the stylus axis direction but in a direction shifted from the axial direction of the stylus 211 (for example, in FIG. 7). B).
In this case, only the component force (Fz) in the stylus axis direction is reflected in the change of the detection signal among the force (Fv) applied to the probe 200 from the surface S to be measured. Therefore, when the detection signal is controlled to the reference level, the pressing of the contact portion 212 against the object to be measured becomes strong, and the measurement force cannot be kept constant. If the measurement force cannot be kept constant in this way, the object surface S to be measured is damaged by strong pressing, or the stylus 211 is bent and the object surface S cannot be accurately detected. Therefore, in the measurement of the surface S to be measured by the vibration contact probe 200, the surface is limited to the object to be measured having a substantially flat surface.

Further, when the surface of the object to be measured is inclined, the portion of the contact portion 212 of the probe 200 that comes into contact with the surface of the object to be measured is different. For example, as shown in FIG. 7A, if the object surface S is horizontal, it contacts the object surface at the lowest point of the contact portion 212, but when the object surface is inclined, The contact portion 212 comes into contact with the surface of the object to be measured at a point closer to the side surface than the lowest point (B in FIG. 7).
In this way, since it is not known at which point of the contact portion 212 it contacts the surface of the object to be measured, the reliability of the measurement data varies depending on the shape of the contact portion 212. Therefore, in order to guarantee the measurement accuracy, the contact portion 212 is a very accurate sphere, or the contact portion 212 from the reference sphere is based on the result of measuring a master (reference sphere or the like) as a reference. The deviation must be corrected.

  However, it is difficult to form the contact portion 212 in a true sphere. In recent years, when the measurement accuracy required when measuring the surface of an object to be measured has been advanced, it is difficult to always obtain a master (reference sphere) calibrated with an accuracy higher than the required measurement accuracy. There is also a limit to the sphericity of the reference sphere. Therefore, in order to guarantee the measurement accuracy, it is necessary to limit at which point of the contact portion 212 the object to be measured comes into contact. It was limited.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface property measuring apparatus that measures the surface of an object to be measured with a high degree of accuracy.

  The surface texture measuring device according to the present invention includes a stylus having a contact portion that contacts the surface of the object to be measured, and a measuring force detection that detects a measuring force in the stylus axial direction when the contact portion contacts the surface of the object to be measured. And a measuring unit that scans and scans the surface of the object to be measured, and a moving mechanism that moves the measuring unit relative to the surface of the object to be measured while keeping the measuring force constant. And a rotation mechanism that rotates the measurement unit with the contact portion as a rotation center so that the stylus is perpendicular to the surface of the object to be measured.

  In such a configuration, the measuring unit scans the surface of the object to be measured by the moving mechanism. At this time, the measurement force acting in the stylus axis direction is detected by the measurement force detection means, and the moving mechanism moves the measurement unit so that the measurement force is constant. During the scanning, the measurement unit is rotated and adjusted by the rotation mechanism so that the stylus is perpendicular to the surface of the object to be measured. In this way, scanning is performed with the stylus perpendicular to the surface of the object to be measured, and the surface shape of the object to be measured is obtained from the coordinate values sampled at a predetermined pitch.

According to such a configuration, since the rotation mechanism is provided, the measurement unit can be rotated to make the stylus perpendicular to the surface of the object to be measured.
For example, even when the surface of the object to be measured has an inclination, the stylus can be made perpendicular to the surface of the object to be measured by adjusting the rotation angle of the measurement unit by the rotation mechanism. By adjusting the stylus so that it is perpendicular to the surface of the object to be measured, the measuring force detecting means can accurately detect the measuring force acting between the contact portion and the surface of the object to be measured. Since the measuring force can be accurately detected by the measuring force detecting means, it is possible to perform a high-precision scanning measurement with a constant measuring force, and also to perform a high-accuracy scanning measurement even on the surface of the object having an inclination. Can be executed.

  In the rotation of the measurement part by the rotation mechanism, the center of rotation is the contact part, so that the contact part is not displaced even if the measurement part is rotated by the rotation mechanism. Therefore, even if the measurement unit is rotated by the rotation mechanism, the contact point (measurement point) where the contact unit is in contact with the surface of the object to be measured does not come off. Therefore, the scanning scanning can be continued while adjusting the angle of the stylus with respect to the surface of the object to be measured by rotating the measuring unit by the rotating mechanism during the scanning scanning.

Since the measurement unit is rotated by the rotation mechanism, the stylus becomes perpendicular to the surface of the object to be measured, so that the contact part comes into contact with the surface of the object to be measured from the stylus axis direction. Since the direction in which the contact portion contacts the surface of the object to be measured is limited only from the stylus axis direction, the point where the contact portion contacts the surface of the object to be measured is limited to one point. Therefore, it is not necessary to make the entire contact portion into a highly accurate sphere or to calibrate the entire contact portion with high accuracy, so that the measurement operation can be simplified and the cost can be reduced.
Further, the measurement accuracy can be improved by calibrating the contact portion only at one point in contact with the surface of the object to be measured.

  Note that the rotation of the measurement unit by the rotation mechanism may be rotation within a predetermined plane, or is not limited to rotation within one plane, and can be rotated in all planes including the contact portion. It may be.

  In the present invention, a counter that samples the driving amount of the moving mechanism at a predetermined sampling pitch, a normal angle of the surface of the object to be measured is calculated based on the count value of the counter, and the stylus is parallel to the normal line It is preferable to include an adjustment angle calculation unit that calculates an adjustment angle.

  In such a configuration, the normal of the surface of the object to be measured is calculated by the adjustment angle calculation unit. Then, the angle difference between the normal of the surface of the object to be measured and the stylus is calculated as the adjustment angle. The measurement unit is rotated by the rotation mechanism by this adjustment angle, so that the stylus is adjusted to be perpendicular to the surface of the object to be measured. Since the adjustment angle can be calculated based on the count value acquired during the execution of the scanning scan, the scanning scanning can be executed while adjusting the stylus so as to be perpendicular to the surface of the object to be measured.

  In the present invention, the adjustment angle calculation unit may calculate a normal of the surface of the object to be measured at the current measurement point based on a line perpendicular to a straight line connecting the current measurement point and the previous measurement point. preferable.

In such a configuration, the adjustment angle calculation unit calculates a straight line connecting the current measurement point and the previous measurement point. Then, the perpendicular of the straight line at the current measurement point is calculated. If the sampling pitch between the current measurement point and the previous measurement point is short, the straight line connecting the current measurement point and the previous measurement point is a straight line that approximates the tangent of the curvature circle on the surface of the object to be measured at the current measurement point. It becomes. Therefore, a straight line that approximates the normal of the surface of the object to be measured at the current measurement point can be obtained from the perpendicular of the straight line.
Then, the stylus can be made perpendicular to the surface of the object to be measured by rotating the measurement unit with a rotation mechanism so that the perpendicular line and the stylus are parallel to each other.

  The normal of the surface of the object to be measured may be obtained based on the current measurement point and the previous measurement point, or a plurality of past measurement points in view of the current measurement point and the current measurement point. The normal of the surface of the object to be measured may be calculated based on the above.

In addition, shape data of the surface of the object to be measured is set and inputted in advance to the adjustment angle calculation unit based on design data of the object to be measured, and the stylus is perpendicular to the surface of the object to be measured at each point on the surface of the object to be measured. You may obtain | require beforehand the adjustment angle for doing.
During the scanning measurement, the adjustment angle calculated in advance may be read sequentially and the measurement unit may be rotated by the rotation mechanism.

  In the present invention, the measurement force detection means includes: an excitation means that causes the stylus to vibrate at a natural frequency in the axial direction; and a detection means that detects a change in vibration of the stylus and outputs a detection signal. Is preferred.

In such a configuration, the stylus is vibrated in the axial direction by the vibration means.
And when a contact part contacts the to-be-measured object surface, the vibration of a stylus will be restrained and a vibration will become small. This vibration change of the stylus is detected by the detecting means.
According to such a configuration, it is possible to detect a force that constrains vibration in the axial direction of the stylus, that is, a force that acts on the stylus from the axial direction of the stylus. Since the rotation mechanism maintains the state in which the stylus is perpendicular to the surface of the object to be measured, the measuring force acts in the stylus axis direction in the scanning. Therefore, it is possible to detect the measurement force during the scanning scan with high accuracy, and it is possible to execute the scanning measurement with a constant measurement force with high accuracy.

  In the present invention, it is preferable that the moving means includes a fine movement mechanism that slightly displaces the measurement unit, and a coarse movement mechanism that displaces the measurement unit together with the fine movement mechanism more than the fine movement mechanism.

Here, for example, it is desirable that the fine movement mechanism is a drive mechanism having a high response speed. For example, a piezoelectric actuator using a piezoelectric element can be given as an example.
An example of the coarse movement mechanism is an electromagnetic actuator.

  According to such a configuration, since the fine movement mechanism and the coarse movement mechanism are provided, in the scanning measurement, the contact portion is quickly minutely formed by the fine movement mechanism having a high response speed with respect to the minute unevenness on the surface of the object to be measured. It can be displaced, and can cope with a large shape change (swell or the like) on the surface of the object to be measured by a coarse motion mechanism that can tolerate a large displacement. As a result, the contact portion can be moved along the surface of the object to be measured with high accuracy and high speed.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be illustrated and described with reference to reference numerals attached to respective elements in the drawings.
(First embodiment)
A first embodiment according to the surface texture measuring apparatus of the present invention will be described.
FIG. 1 is a diagram showing a configuration of a first embodiment according to the surface texture measuring apparatus 100 of the present invention.
In the first embodiment, a case is described in which a measurement object having a substantially flat surface is arranged substantially horizontally and the probe 200 is approached to the measurement object surface S from above the measurement object surface S for measurement. To do.

  The surface texture measuring apparatus 100 includes a probe 200 that detects the surface of the object to be measured S while moving the measuring unit 210 in contact with the surface of the object to be measured S in the vertical direction by the vertical drive mechanism 220, and the probe 200 is moved in three dimensions. A three-dimensional drive mechanism 300 to be rotated, a rotation mechanism 400 that rotates the probe 200 to make the probe 200 perpendicular to the surface of the object to be measured, a vertical drive mechanism control unit 500 that drives and controls the vertical drive mechanism 220, And a controller unit 600 that performs operation control.

  The probe 200 is in contact with the measurement object surface S to detect a measurement force on the measurement object surface S, and a vertical drive mechanism 220 that moves the measurement unit 210 up and down according to the shape of the measurement object surface S. And a displacement amount detection sensor 230 that detects the amount of vertical displacement of the measurement unit 210.

The measurement unit 210 is the vibration contact probe 200 described in the background art.
A stylus 211 having a contact portion 212 at the tip; a stylus holder 213 that supports the stylus 211; a vibration means 214 that oscillates the stylus 211 at a natural frequency in the axial direction; and a vibration change of the stylus 211 is detected. Detecting means 217 for outputting a measuring force signal.
The vibration means 214 includes a piezoelectric element 215 that is provided in the stylus holder 213 and vibrates the stylus 211, and an excitation circuit 216 that applies an output signal (pulse or sine wave signal or the like) having a predetermined frequency to the piezoelectric element 215. Prepare.
The detection means 217 includes a piezoelectric element 218 that converts the vibration of the stylus 211 into a voltage,
A measurement force detection circuit 219 that detects a voltage from the piezoelectric element 218 and outputs a measurement force signal.

When the measuring force detection circuit 219 detects the voltage from the piezoelectric element 218, the voltage detected when the contact portion 212 vibrates freely, and the contact portion 212 is constrained by contact with the surface S to be measured. The difference from the voltage detected in the state is output as information on the measuring force that the contact portion 212 receives from the surface S of the object to be measured.
For example, referring to FIG. 8, a value obtained by subtracting a reference value L2 that is a voltage level when the contact portion 212 is pushed into the surface S of the object to be measured with a predetermined measurement force from the voltage level L1 at the time of non-contact is detected by the measurement force The measurement force detected by the circuit 219.

  The vertical drive mechanism 220 includes a fine movement mechanism 221 that displaces the measurement unit 210 in a very small range, and a coarse movement mechanism 222 that displaces the measurement unit 210 together with the fine movement mechanism 221. Then, the fine movement mechanism 221 having a fast response speed and the coarse movement mechanism 222 having a large movable range allow the fine movement mechanism 221 to quickly cope with minute irregularities on the surface of the object to be measured, and coarse movement to a large change such as swell. Corresponding with the mechanism 222, the contact portion 212 is moved along the surface of the object to be measured with high accuracy and quickly at the time of scanning measurement.

The fine movement mechanism 221 is composed of, for example, a piezoelectric element, and is attached to the movable portion 223 of the coarse movement mechanism 222.
Measurement unit 210 is supported by the lower end of fine movement mechanism 221.

  The coarse movement mechanism 222 is configured by, for example, an electromagnetic actuator including a permanent magnet fixed to a housing 224 that is a casing and a movable coil that moves in the vertical direction in the magnetic field of the magnet. In this case, the movable coil is provided with a movable portion 223 that moves integrally with the movable coil.

The displacement amount detection sensor 230 includes a linear encoder that includes a scale 231 that moves up and down integrally with the measurement unit 210 and a detection head 232 that detects the displacement of the scale 231. The displacement amount detection sensor 230 detects the displacement amount of the measurement unit 210 with respect to the housing 224. That is, the displacement amount detection sensor 230 detects the combined displacement amount of the coarse movement mechanism 222 and the fine movement mechanism 221.
The detection result by the displacement detection sensor 230 is output as a displacement signal.

The three-dimensional drive mechanism 300 has the same configuration as that described in the background art (not explicitly shown in FIG. 1) (see FIG. 5), and one having an X, Y, and Z direction slide mechanism is used.
Specifically, the three-dimensional drive mechanism 300 is slidable to the left and right through a portal frame 320 erected so as to be slidable back and forth with respect to the mounting table 310 and a beam portion 321 of the portal frame 320. And a Z spindle 340 slidable up and down in the Z column 330.
The probe 200 is attached to the Z spindle 340 via the rotation mechanism 400. Each axis of the three-dimensional drive mechanism 300 is provided with an encoder (not shown) that detects a drive amount.

As shown in FIG. 2, the rotating mechanism 400 includes an arc-shaped guide rail 410 provided on the side surface of the Z spindle 340, a slider 420 provided on the probe 200 and slidable along the guide rail 410, Is provided.
The guide rail 410 has an arc shape, and this arc is a part of a circle C centered on the contact portion 212.
The radius r of this arc is the length from the mounting position of the guide rail 410 to the contact portion 212 in a state where the displacement amounts of the coarse motion mechanism 222 and the fine motion mechanism 221 are zero.
The slider 420 is provided so as to straddle the guide rail 410 (see FIG. 1). When the slider 420 slides on the guide rail 410, the probe 200 rotates about the contact portion 212 as the center of rotation, and the probe 200 tilts. An encoder that detects the sliding amount of the slider 420 is provided between the guide rail 410 and the slider 420.

Here, the vertical drive mechanism 220, the three-dimensional drive mechanism 300, and the rotation mechanism 400 constitute a moving mechanism.
Further, the vibrating means 214 and the detecting means 217 constitute a measuring force detecting means.

  The vertical drive mechanism control unit 500 includes a fine movement mechanism control unit 510 that drives and controls the fine movement mechanism 221, and a coarse movement mechanism control unit 520 that drives and controls the coarse movement mechanism 222.

The fine movement mechanism control unit 510 calculates a displacement amount of the fine movement mechanism 221 for making the measurement force detected by the measurement force detection circuit 219 constant at the specified measurement force, by the fine movement displacement information calculation circuit 511, and the fine movement mechanism drive circuit 512. A control signal such as a voltage is applied to the fine movement mechanism 221 via.
The coarse movement mechanism control unit 520 calculates the displacement amount of the coarse movement mechanism 222 that causes the displacement amount of the fine movement mechanism 221 to be a predetermined balance displacement, and the coarse movement mechanism 222 via the coarse movement mechanism drive amplifier 550. A control signal such as current is applied to.

Fine movement mechanism control unit 510 is a feedback loop for making measurement force constant at a specified acting force by means of measurement force comparator 513, fine movement displacement information calculation circuit 511, and fine movement mechanism drive circuit 512.
The coarse movement mechanism control section 520 controls the position from the coarse movement displacement control section 530 having the position comparator 531 and the position compensator 532 to the coarse movement mechanism drive amplifier 550 via the coarse movement speed control section 540. A loop, and a speed control loop from the probe counter 541 to the speed compensator 545 via the displacement comparator 542, the differentiation circuit 543, and the speed comparator 544.

  The controller unit 600 includes a three-dimensional drive mechanism control unit 610, a counter unit 620, a shape analysis unit 630, an adjustment angle calculation unit 640, a rotation mechanism control unit 650, and a CPU 660.

The three-dimensional drive mechanism control unit 610 controls the three-dimensional drive mechanism 300 to move the probe 200 in the X direction, the Y direction, and the Z direction.
For example, when performing scanning measurement, the probe 200 is moved in a predetermined scanning direction.

The counter unit 620 includes a three-dimensional counter 621 and a rotation amount counter 622.
The three-dimensional counter 621 counts the driving amount of the three-dimensional drive mechanism 300 in the X direction, the Y direction, and the Z direction.
The rotation amount counter 622 counts the rotation angle of the probe 200 by detecting the displacement amount of the slider 420.

The shape analysis unit 630 calculates the surface shape of the object to be measured based on the drive amounts of the vertical drive mechanism 220, the three-dimensional drive mechanism 300, and the rotation mechanism 400 counted by the probe counter 541 and the counter unit 620.
That is, the shape analysis unit 630 calculates the displacement amount of the contact unit 212 by combining the drive amounts of the vertical drive mechanism 220 and the three-dimensional drive mechanism 300, and the displacement amount of the contact unit 212 based on the rotation angle of the probe 200. Is corrected to calculate the movement locus of the contact portion 212.
The movement trajectory of the contact portion 212 becomes the surface shape of the object to be measured.

  The adjustment angle calculation unit 640 calculates an adjustment angle for rotating the probe 200 so that the probe 200 is perpendicular to the surface of the object to be measured. First, the adjustment angle calculation unit 640 calculates the normal of the surface of the object to be measured at the current measurement point using a line perpendicular to the straight line connecting the current measurement point and the previous measurement point. Then, the rotation angle of the probe 200 necessary for making the calculated normal to the surface of the object to be measured parallel to the stylus 211 is calculated as an adjustment angle.

For example, FIG. 3 is a diagram illustrating a state in which the probe 200 has moved from the point P ₀ to the point P ₁ . A case will be described in which the point P ₀ is moved to the point P ₁ and the stylus 211 is made perpendicular to the surface of the object to be measured at the current measurement point P ₁ .
First, a straight line l ₁ connecting the point P ₀ that is the previous measurement point and the point P ₁ that is the current measurement point is calculated.
Next, the perpendicular n ₁ at the point P1 is calculated with respect to the straight line l ₁ .
Then, an angle θ ₁ formed by the current probe 200 and the perpendicular n ₁ is obtained.
This angle θ ₁ is the adjustment angle at the point P ₁ .

  The rotation mechanism control unit 650 drives and controls the rotation mechanism 400 to rotate the probe 200 according to the adjustment angle. That is, the rotation mechanism control unit 650 drives the rotation mechanism 400 according to the adjustment angle calculated by the adjustment angle calculation unit 640 to make the probe 200 perpendicular to the surface of the object to be measured.

  The CPU 660 controls the controller unit 600 and outputs a copy designation measuring force command to the measuring force comparator 513.

The operation of the first embodiment having such a configuration will be described.
First, the designated measurement force input to the measurement force comparator 513 and the balance displacement amount of the fine movement mechanism 221 input to the position comparator 531 are set. Then, the three-dimensional drive mechanism 300 is driven by the drive control by the three-dimensional drive mechanism control unit 610, and the contact unit 212 moves while being in contact with the surface of the object to be measured. At this time, design data of the object to be measured and data such as a measurement site in the scanning measurement are input to the three-dimensional drive control unit in advance, and the three-dimensional drive mechanism control unit so that the probe 200 scans the surface of the object to be measured. The three-dimensional drive mechanism 300 is controlled by 610. The measuring force is detected by the measuring force detection circuit 219. The vertical drive mechanism 220 (fine movement mechanism 221 and coarse movement mechanism 222) is driven and controlled by the vertical drive mechanism control section 500 so that the detected measurement force becomes constant at the specified measurement force, and the measurement section 210 is measured on the surface of the object to be measured. It is moved up and down according to the unevenness.

  Here, since the measuring force detection circuit 219 can detect only the measuring force acting in the axial direction of the stylus 211, the rotating mechanism 400 is arranged so that the stylus 211 is perpendicular to the surface of the object to be measured during the scanning. Thus, the probe 200 is rotationally driven.

With reference to FIG. 3 and FIG. 4, the operation | movement in which a probe angle is adjusted according to the inclination of the to-be-measured object surface is demonstrated.
3 and 4, it is assumed that the probe 200 measures the surface of the object to be measured in the order of point P ₀ → point P ₁ → point P ₂ .
In FIG. 3, when the probe 200 moves from the point P ₀ to the point P ₁ , first, the probe 200 starts from a state where the probe 200 is perpendicular to the surface of the object to be measured at the point P ₀ . Three-dimensional drive mechanism 300 and the vertical movement drive mechanism 220 (the fine feed mechanism 221, the coarse feed mechanism 222) scanning scanning at constant measuring force to the point P ₁ is the next measurement point is performed by.
Now that led to the point P _1, the coordinate value of the point P ₁ is detected. That is, the driving amount of the three-dimensional driving mechanism 300 counted by the three-dimensional counter 621 and the driving amount of the vertical driving mechanism 220 counted by the probe counter 541 are combined by the shape analysis unit 630 to obtain the coordinate value of the point P _1. It is done.

At the point P _1, the angle of the probe 200 is adjusted to be perpendicular to the workpiece surface. At this time, the coordinate value of the point P ₀ that is the previous measurement point and the coordinate value of the point P ₁ that is the current measurement point are output from the shape analysis unit 630 to the adjustment angle calculation unit 640.
Then, the adjustment angle calculation unit 640 first calculates a straight line l ₁ that connects the point P ₀ and the point P ₁ .
Subsequently, the adjustment angle calculation unit 640 calculates a perpendicular line n ₁ of the straight line l _{1 at} the point P ₁ . Then, the angle difference θ ₁ between the perpendicular n ₁ and the probe 200 is calculated as the adjustment angle.

The calculated adjustment angle θ ₁ is output to the rotation mechanism control unit 650. The rotation mechanism control unit 650 drives the rotation mechanism 400 by the adjustment angle θ ₁ and slides the slider 420. Then, rotating the probe 200 at the position of the point P ₁ is about the contact portion 212, the probe 200 is perpendicular to the workpiece surface.

In addition, since the probe 200 performs a rotational motion around the contact portion 212, the rotation mechanism control unit 650 drives the rotation mechanism 400 because the distance from the rotation mechanism 400 to the contact portion 212 is the driving radius of the rotation mechanism 400. This is when r is equal to r, that is, when the amount of displacement of the coarse movement mechanism 222 and the fine movement mechanism 221 is zero.
Therefore, the vertical drive mechanism 220 is driven before the rotation mechanism 400 is driven to adjust the distance between the contact portion 212 and the rotation mechanism 400 as necessary.

Thus the probe 200 at point P ₁ is in a condition that the normal to the workpiece surface, then the probe 200 is moved Following the point P _2. Then, the coordinate values are detected at the point P _2, the angle of the probe 200 as the probe 200 at the point P ₂ is perpendicular to the workpiece surface is adjusted. That is, the adjustment angle calculation unit 640 calculates a straight line l ₂ connecting the point P ₁ and the point P ₂ and calculates a perpendicular line n _{2 of the} straight line l ₂ at the point P ₂ . Then, the adjustment angle calculation unit 640 calculates the angle difference θ ₂ between the perpendicular n ₂ and the probe 200, and the rotation mechanism so that the probe 200 is perpendicular to the surface of the object to be measured based on the angle difference θ _2. The rotation mechanism 400 is driven by the control unit 650.

  In this way, the scanning of the surface of the object to be measured by the probe 200 is performed, and the surface shape of the object to be measured is obtained by the shape analysis unit 630 based on the count values of the three-dimensional counter 621 and the probe counter 541.

According to 1st Embodiment provided with such a structure, there can exist the following effects.
(1) Since the rotation mechanism 400 is provided, the probe 200 can be rotated to make the stylus 211 perpendicular to the surface of the object to be measured. Therefore, even when the surface of the object to be measured has an inclination, the stylus 211 can be made perpendicular to the surface of the object to be measured by adjusting the rotation angle of the probe 200 by the rotation mechanism 400. By adjusting the stylus 211 to be perpendicular to the surface of the object to be measured, the measuring force acting between the contact portion 212 and the surface of the object to be measured can be accurately detected. Since the measuring force can be accurately detected, scanning measurement with a constant measuring force can be performed with high accuracy, and further, high-accuracy scanning measurement can be performed even on an object surface having an inclination. .

(2) When the probe 200 is rotated by the rotation mechanism 400, the center of rotation is the contact portion 212. Therefore, even if the probe 200 is rotated by the rotation mechanism 400, the contact portion 212 is not displaced. Therefore, even if the probe 200 is rotated by the rotation mechanism 400, the contact point (measurement point) where the contact portion 212 is in contact with the surface of the object to be measured does not come off. Accordingly, the scanning scan can be continued while the probe 200 is rotated by the rotating mechanism 400 during the scanning scanning and the angle of the stylus 211 with respect to the surface of the object to be measured is adjusted as needed.

(3) When the probe 200 is rotated by the rotation mechanism 400, the stylus 211 becomes perpendicular to the surface of the object to be measured, so that the contact portion 212 comes into contact with the surface of the object to be measured from the stylus axis direction. Since the direction in which the contact part 212 contacts the surface of the object to be measured is limited only from the stylus axis direction, the point where the contact part 212 contacts the surface of the object to be measured can be limited to one point. Therefore, it is not necessary to make the entire contact portion 212 a highly accurate sphere or to calibrate the entire contact portion 212 with high accuracy, so that the measurement operation can be simplified and the cost can be reduced. In addition, the measurement accuracy can be improved by calibrating the contact portion 212 only at one point in contact with the surface of the object to be measured.

The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the configuration of the rotation mechanism is not limited to the above embodiment, and any configuration may be used as long as the probe is rotated about the contact portion as the rotation center. Note that the rotation of the measurement unit by the rotation mechanism may be rotation within a predetermined plane, or is not limited to rotation within one plane, and can be rotated in all planes including the contact portion. It may be. Specifically, an arcuate guide rail may be provided in a plane orthogonal to the guide direction of the guide rail 410, and the probe 200 may be rotated in two planes orthogonal to each other.
Further, a spherical bearing is used instead of the guide rail 410 as a rotation mechanism, and the probe 200 is rotatably held in an arbitrary direction, whereby the axial direction of the stylus 211 can be made coincident with the normal direction of the workpiece surface. It may be.

  The present invention can be used for a surface texture measuring apparatus.

The figure which shows the structure of 1st Embodiment which concerns on the surface texture measuring apparatus of this invention. The figure which shows a mode that a probe is rotated by the rotation mechanism. It shows a state in which the probe is moved from point P ₀ to point P _1. It shows a state in which the probe is moved from point P ₁ to point P _2. The figure which shows the structure of the surface property measuring apparatus using a probe. The figure which shows an excitation type contact type probe. The figure which shows a mode that the to-be-measured object surface is scanned by a probe. The figure which shows the change of the detection signal with respect to the position of a probe and a to-be-measured object surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Surface texture measuring device, 200 ... Probe, 210 ... Measurement part, 211 ... Stylus, 212 ... Contact part, 213 ... Stylus holder, 214 ... Excitation means, 215 ... Piezoelectric element, 216 ... Excitation circuit, 217 ... Detection Means, 218 ... piezoelectric element, 219 ... measuring force detection circuit, 220 ... vertical drive mechanism, 221 ... fine movement mechanism, 222 ... rough movement mechanism, 223 ... movable part, 224 ... housing, 230 ... displacement detection sensor, 231 ... scale 232 ... detection head, 300 ... three-dimensional drive mechanism, 310 ... mounting table, 320 ... gate frame, 321 ... beam, 330 ... Z column, 340 ... Z spindle, 400 ... rotation mechanism, 410 ... guide rail, 420 ... Slider, 500 ... Vertical drive mechanism control unit, 510 ... Fine movement mechanism control unit, 511 ... Fine movement displacement information calculation circuit, 512 ... Fine movement mechanism Moving circuit, 513... Measuring force comparator, 520... Coarse movement mechanism control unit, 530... Coarse movement displacement control unit, 531... Position comparator, 532. , 542 ... Displacement comparator, 543 ... Differentiating circuit, 544 ... Speed comparator, 545 ... Speed compensator, 550 ... Coarse mechanism drive amplifier, 600 ... Controller part, 610 ... Three-dimensional drive mechanism control part, 620 ... Counter part 621 ... Three-dimensional counter, 622 ... Rotation amount counter, 630 ... Shape analysis unit, 640 ... Adjustment angle calculation unit, 650 ... Rotation mechanism control unit, 660 ... CPU.

Claims (5)

A surface of the object to be measured, comprising: a stylus having a contact portion in contact with the surface of the object to be measured; and a measuring force detecting means for detecting a measuring force in a stylus axial direction when the contact part contacts the surface of the object to be measured. A measurement unit that scans and scans,
A moving mechanism for moving the measuring unit relative to the surface of the object to be measured while keeping the measuring force constant,
The movement mechanism includes a rotation mechanism that rotates the measurement unit around the contact portion as a rotation center so that the stylus is perpendicular to the surface of the object to be measured. In the surface texture measuring apparatus according to claim 1,
A counter that samples the driving amount of the moving mechanism at a predetermined sampling pitch;
An adjustment angle calculation unit that calculates an angle of a normal to the surface of the object to be measured based on a count value of the counter and calculates an adjustment angle for making the stylus parallel to the normal,
A surface texture measuring device comprising: In the surface texture measuring device according to claim 2,
The adjustment angle calculation unit
A surface property measuring apparatus characterized by calculating a normal of the surface of the object to be measured at the current measurement point based on a line perpendicular to a straight line connecting the current measurement point and the previous measurement point. In the surface texture measuring device according to any one of claims 1 to 3,
The measuring force detecting means includes
Vibration means for causing the stylus to vibrate at a natural frequency in the axial direction;
Detecting means for detecting a change in vibration of the stylus and outputting a detection signal. In the surface texture measuring device according to any one of claims 1 to 4,
The moving means includes a fine movement mechanism for minutely displacing the measurement unit;
A surface texture measuring apparatus comprising: a coarse motion mechanism that causes the measurement unit to be displaced more than the fine motion mechanism together with the fine motion mechanism.

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