JP2003097940A - Method and device for shape measuring, storage medium storing computer program for shape measuring, and computer program for shape measuring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for shape measuring capable of accurately detecting an initial position of a probe even if the probe vibrates in a machine resonant frequency to shorten measuring time, as well as making every effort to inhibit any disadvantage such as its structural complexity or others, etc., due to the above measuring operation. SOLUTION: In performing a shape measuring method so that a detecting means 3 detects the displacement of the contact type probe brought in contact with a surface to be measured from its initial position to measure the shape of the surface, an operation processing is provided in order to detect the displacement of the probe through the detecting means 3 and then obtain a signal which may be considered as the initial position of the probe for its output signal. Thus the initial position of the probe can accurately be detected in a short time only by using the operation processing without changing mechanism of the probe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stores a shape measuring method, a shape measuring device, and a computer program for measuring the shape, in which a surface to be measured of a lens, a mold or the like is measured by using a contact type probe. The present invention relates to a storage medium and a computer program for shape measurement.

[0002]

2. Description of the Related Art Conventionally, a shape measuring device equipped with a stylus probe has been developed in order to measure a minute shape with high accuracy.

FIG. 1 is a vertical sectional front view showing an example of a stylus type probe.

In FIG. 1, reference numeral 1 is a true sphere that is attached to the tip of the stylus 2 and comes into contact with an object to be contacted. A displacement gauge 3 for detecting the displacement of the stylus 2 is provided above the stylus 2 so as to face the upper end of the stylus 2. The stylus 2 and the displacement meter 3 are held in the housing 4. The stylus 2 is laterally constrained and vertically displaceable without sliding resistance, while being supported by the static pressure air bearing 5 supplied from the air supply hole 6 in a non-contact manner with the housing 4. . The displacement meter 3 is fixed to the upper end of the housing 4. The housing 4 is mounted on a moving stage (not shown) that is driven in the same direction as the displacement direction of the stylus 2.

In FIG. 1, a spring 7 is a leaf spring that supports the stylus 2 and is fixed to the housing 4. As the spring 7 that supports the stylus 2, a leaf spring is illustrated in FIG. 1, but the spring 7 is not limited to a leaf spring, but may be a coil spring, a hinge, an air spring, a magnetic spring, or the like. Regardless of the mechanism, any mechanism may be used as long as the force is generated by the displacement. Further, the lateral support mechanism of the stylus 2 is not limited to the static pressure air bearing 5, and any support mechanism having a high lateral rigidity such as a parallel leaf spring may be used. Further, the displacement meter 3 may be of any type such as an optical type, an electrostatic capacitance type, an actuating transformer type and the like.

Next, the basic operation of the shape measuring apparatus will be described.

When measuring the shape of the surface to be measured (not shown), the true sphere 1 at the tip of the stylus 2 is pressed against the surface to be measured. As a result, the stylus 2 moves to a position where the spring force of the spring 7 and the reaction force from the surface to be measured are balanced. At this time, the output of the displacement meter 3 changes. Therefore, the movement stage equipped with the housing 4 is drive-controlled so that the output of the displacement meter 3 is always constant. As a result, the contact load of the stylus 2 on the surface to be measured is kept constant. In this way
With the contact load kept constant, the scanning moving stage is driven to scan the surface to be measured. The scanning locus at this time becomes the shape of the surface to be measured.

[0008]

In the stylus type probe having the above-mentioned principle, the stylus 2 is supported by the spring 7, and the static pressure air bearing 5 is used to support the sliding resistance. Therefore, there is a problem that vibration easily occurs at the mechanical resonance frequency obtained by the weight of the stylus 2 and the spring constant of the spring 7 supporting the stylus 2, and the damping is difficult. Stylus 2
If it vibrates, it will be difficult to detect the initial position of the stylus 2, and the error in the displacement corresponding to the contact load will also increase, making accurate shape measurement difficult.

For this reason, conventional measures have been taken to solve the problem that accurate shape measurement is difficult because the stylus easily vibrates at the mechanical resonance frequency.

In Japanese Unexamined Patent Publication No. 9-96518, a vibration damping mechanism using a viscous fluid acting in one axis direction is provided on the probe in order to damp the vibration of the stylus probe in the shape measuring apparatus. The invention is described.

Japanese Unexamined Patent Publication No. 2000-155019 describes an invention in which a moving stage is moved under a low resonance control in order to suppress residual vibration of a stylus probe in a shape measuring apparatus.

Japanese Unexamined Patent Publication No. 2000-298013 discloses an invention in which different materials are attached to a spring supporting a probe in order to damp the vibration of a stylus probe in a shape measuring apparatus.

However, since the invention described in each of these publications is based on the attempt to suppress the mechanical vibration of the probe, some structure is inevitably added to the basic structure of the shape measuring device. However, there is a problem in that it causes inconvenience such as complication of the structure.

In particular, in the invention disclosed in Japanese Patent Laid-Open No. 9-96518, a seal mechanism for handling a viscous fluid complicates the probe mechanism or increases the probe weight. There is a problem. Considering the improvement of probe response and suppression of jumping vibration,
The disadvantage of increasing the weight of the probe is extremely large.

Further, the invention disclosed in Japanese Patent Laid-Open No. 2000-155019 merely proposes a method of driving the moving stage so that the probe is less likely to vibrate, and improves the damping of the vibration itself of the probe. I'm not aiming.

Further, the invention described in Japanese Patent Laid-Open No. 2000-298013 is disclosed in, for example, Japanese Patent Laid-Open No. 9-96518.
Although a mechanism for improving the damping property of the probe by a simple mechanism is proposed as compared with the invention described in Japanese Patent Publication, there is no effect of converging the vibration of the probe.

An object of the present invention is to accurately detect the initial position of the stylus even if the stylus vibrates at the mechanical resonance frequency and improve the accuracy of shape measurement on the surface to be measured.

An object of the present invention is to accurately detect the initial position of the stylus even if the stylus vibrates at the mechanical resonance frequency, and shorten the measuring time for shape measurement on the surface to be measured.

An object of the present invention is to prevent the complication of the structure and other disadvantages from occurring as much as possible in order to achieve the above object.

[0020]

The invention according to claim 1 is
In the shape measuring method for detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means to measure the shape of the surface to be measured, from the probe located at the initial position An initial signal detecting step of detecting an output signal by the detecting means, and an arithmetic step of performing an arithmetic process for obtaining a signal that can be regarded as an initial position of the probe with respect to the output signal of the detecting means. To do.

Therefore, the initial position of the probe is detected only by the arithmetic processing without changing the mechanism of the probe.

According to a second aspect of the present invention, in the shape measuring method according to the first aspect, in the initial signal detecting step, the output signal from the probe which is not in contact with the surface to be measured is detected by the detecting means. Detect by.

Therefore, without changing the mechanism of the probe, the initial position of the probe which is not in contact with the measurement surface is detected only by the arithmetic processing.

According to a third aspect of the present invention, in the shape measuring method according to the first aspect, in the initial signal detecting step, an output signal from the probe in contact with the surface to be measured is detected by the detecting means. To detect.

Therefore, the initial position of the probe which is in contact with the measurement surface can be detected only by the arithmetic processing without changing the mechanism of the probe.

According to a fourth aspect of the present invention, in the shape measuring method according to the first, second or third aspect, the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe,
This is an averaging process for the output signal of the detecting means within a specified time interval.

Therefore, a signal that can be regarded as the initial position of the probe is easily obtained.

According to a fifth aspect of the present invention, in the shape measuring method according to the first, second or third aspect, the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe,
It is a low-pass filter process for the output signal of the detection means.

Therefore, in obtaining a signal that can be regarded as the initial position of the probe, it is possible to reduce the load of arithmetic processing and the resources for arithmetic processing.

The invention according to claim 6 is the invention according to claims 1, 2 and
In the shape measuring method according to 3, 4, or 5, the calculation process for obtaining a signal that can be regarded as the initial position of the probe is performed when the value based on the output signal of the detecting means converges to a specified range. A vibration convergence determination process for determining that the probe vibration has converged is included.

Therefore, the convergence of the vibration of the probe is determined only by the arithmetic processing without changing the mechanism of the probe. Accordingly, the vibration convergence determination of the probe can be performed without depending on the vibration damping performance of the probe, and it is correctly determined whether the vibration is the probe vibration or the probe has contacted the object.

According to a seventh aspect of the present invention, in the shape measuring method according to the sixth aspect, the value based on the output signal of the detecting means is a peak hold value within a prescribed time interval.

Therefore, when it is determined that the value based on the output signal of the detecting means has converged within the specified range, it is possible to reduce the load of the arithmetic processing and the resources for the arithmetic processing.

According to an eighth aspect of the present invention, in the shape measuring method according to the sixth aspect, the value based on the output signal of the detecting means is dispersion within a specified time interval.

Therefore, when it is determined that the value based on the output signal of the detecting means has converged within the specified range, the change of the convergence characteristic due to the change of the probe or the spring, the change with time,
It is robust against external disturbances and the accuracy of its determination is improved.

The invention according to claim 9 is the shape measuring method according to claim 4, 7 or 8, wherein the specified time interval is
It is an interval equal to or longer than the vibration period represented by the reciprocal of the mechanical resonance frequency of the probe.

Therefore, a prescribed time interval sufficient to obtain the accuracy of state detection is prescribed.

According to a tenth aspect of the present invention, in the shape measuring method according to the fourth, seventh or eighth aspect, the data acquisition period or the calculation period within the specified time interval is represented by the reciprocal of the mechanical resonance frequency of the probe. The interval is less than 1/2 of the vibration cycle.

Therefore, a prescribed time interval sufficient to obtain the accuracy of state detection is prescribed.

According to an eleventh aspect of the present invention, in the shape measuring method according to the tenth aspect, the data acquisition period or the calculation period is variable.

Therefore, it becomes possible to set the prescribed time interval sufficient for obtaining the accuracy of the state detection, for example, according to various conditions.

The invention of the shape measuring method according to claim 12 is
When the vibration convergence determination process according to claim 6, 7 or 8 determines that the vibration of the probe has converged, the calculation step according to claim 1, 2, 3, 4 or 5 is performed to obtain This value is set to the initial position of the probe.

Therefore, it is possible to accurately calculate the initial position of the probe while reducing the error due to the vibration of the probe. In this way, since the initial position of the probe can be detected with high accuracy, the contact load can be set with high accuracy, and for example, the shape can be measured with high accuracy without damaging the plastic lens or the mold.

According to a thirteenth aspect of the present invention, the shape measuring device is adapted to measure the shape of the surface to be measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. In order to obtain a signal that can be regarded as the initial position of the probe with respect to the output signal of the detection means and the initial signal detection means for detecting the output signal from the probe located at the initial position by the detection means. And an arithmetic means for performing the arithmetic processing of.

Therefore, the initial position of the probe can be detected only by the arithmetic processing without changing the mechanism of the probe.

According to a fourteenth aspect of the present invention, in the shape measuring apparatus according to the thirteenth aspect, the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe is performed based on a value based on the output signal of the detecting means. It includes a vibration convergence determination process for determining that the vibration of the probe has converged when it converges within a prescribed range.

Therefore, the convergence of the vibration of the probe is determined only by the arithmetic processing without changing the mechanism of the probe. Accordingly, the vibration convergence determination of the probe can be performed without depending on the vibration damping performance of the probe, and it is correctly determined whether the vibration is the probe vibration or the probe has contacted the object.

According to a fifteenth aspect of the invention, in the shape measuring apparatus according to the fourteenth aspect, the detection means is initialized when it is determined that the vibration of the probe has converged.

Therefore, in calculating the initial position of the probe after reducing the error due to the vibration of the probe,
Since the detection means is initialized, the calculation process becomes easy.

According to a sixteenth aspect of the present invention, the arithmetic processing according to the thirteenth aspect is executed when the vibration convergence determination processing according to the fourteenth or fifteenth aspect determines that the vibration of the probe has converged. The obtained value was set to the initial position of the probe.

Therefore, it is possible to accurately calculate the initial position of the probe while reducing the error due to the vibration of the probe. In this way, since the initial position of the probe can be detected with high accuracy, the contact load can be set with high accuracy, and for example, the shape can be measured with high accuracy without damaging the plastic lens or the mold.

According to a seventeenth aspect of the present invention, there is provided a storage medium for storing a computer program. Installed on a computer equipped with a shape measuring device that is designed to measure,
This computer is provided with an initial signal detection function of detecting the output signal from the probe located at the initial position by the detection means, and a signal that can be regarded as the initial position of the probe with respect to the output signal of the detection means. And an arithmetic function for performing arithmetic processing for obtaining.

Therefore, the initial position of the probe can be detected only by the arithmetic processing without changing the mechanism of the probe.

According to an eighteenth aspect of the present invention, in the storage medium according to the seventeenth aspect, a value based on an output signal of the detecting means is specified in the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe. Vibration convergence determination processing for determining that the vibration of the probe has converged when it converges to the range.

Therefore, the convergence of the vibration of the probe is determined only by the arithmetic processing without changing the mechanism of the probe. Accordingly, the vibration convergence determination of the probe can be performed without depending on the vibration damping performance of the probe, and it is correctly determined whether the vibration is the probe vibration or the probe has contacted the object.

According to a nineteenth aspect of the present invention, the shape of the surface to be measured is measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. The probe is installed in a computer included in the shape measuring device, and the computer has an initial signal detection function of detecting an output signal from the probe located at an initial position by the detection means and the probe with respect to the output signal of the detection means And an arithmetic function for performing arithmetic processing for obtaining a signal that can be regarded as the initial position of the.

Therefore, the initial position of the probe can be detected only by the arithmetic processing without changing the mechanism of the probe.

According to a twentieth aspect of the present invention, in the computer program according to the nineteenth aspect, a value based on the output signal of the detecting means is specified for the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe. Vibration convergence determination processing for determining that the vibration of the probe has converged when it converges to the range.

Therefore, the convergence of the vibration of the probe is determined only by the arithmetic processing without changing the mechanism of the probe. Accordingly, the vibration convergence determination of the probe can be performed without depending on the vibration damping performance of the probe, and it is correctly determined whether the vibration is the probe vibration or the probe has contacted the object.

According to a twenty-first aspect of the invention, the shape measuring method is adapted to measure the shape of the surface to be measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. In the initial signal detection step of detecting the output signal from the probe located at the initial position by the detecting means, the vibration of the probe converges when the value based on the output signal of the detecting means converges to a specified range. And a vibration convergence determining step for determining that it is performed.

Therefore, the convergence of the vibration of the probe is determined only by the arithmetic processing without changing the mechanism of the probe. Accordingly, the vibration convergence determination of the probe can be performed without depending on the vibration damping performance of the probe, and it is correctly determined whether the vibration is the probe vibration or the probe has contacted the object.

According to a twenty-second aspect of the present invention, the shape measuring apparatus is adapted to measure the shape of the surface to be measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. In, initial signal detection means for detecting the output signal from the probe located at the initial position by the detection means, and vibration of the probe converges when the value based on the output signal of the detection means converges to a specified range. Means for performing a vibration convergence determination process for determining that
It is equipped with.

Therefore, the convergence of the vibration of the probe is determined only by the arithmetic processing without changing the mechanism of the probe. Accordingly, the vibration convergence determination of the probe can be performed without depending on the vibration damping performance of the probe, and it is correctly determined whether the vibration is the probe vibration or the probe has contacted the object.

In the storage medium of the twenty-third aspect of the present invention, the displacement of the contact type probe brought into contact with the surface to be measured from the initial position is detected by the detecting means to measure the shape of the surface to be measured. It is installed in a computer included in the shape measuring device, and an initial signal detection function of detecting an output signal from the probe located at an initial position by the detection means and a value based on the output signal of the detection means are defined in the computer. A computer program for executing a function of performing a vibration convergence determination process for determining that the vibration of the probe has converged when the vibration converges to a range is stored.

Therefore, the convergence of the vibration of the probe is determined only by the arithmetic processing without changing the probe mechanism. Accordingly, the vibration convergence determination of the probe can be performed without depending on the vibration damping performance of the probe, and it is correctly determined whether the vibration is the probe vibration or the probe has contacted the object.

According to a twenty-fourth aspect of the present invention, the displacement of the contact type probe brought into contact with the surface to be measured from the initial position is detected by the detecting means to measure the shape of the surface to be measured. It is installed in a computer included in the shape measuring device, and an initial signal detection function of detecting an output signal from the probe located at an initial position by the detection means and a value based on the output signal of the detection means are defined in the computer. And a function of performing a vibration convergence determination process for determining that the vibration of the probe has converged when it converges to the range.

Therefore, the convergence of the vibration of the probe is determined only by the arithmetic processing without changing the mechanism of the probe. Accordingly, the vibration convergence determination of the probe can be performed without depending on the vibration damping performance of the probe, and it is correctly determined whether the vibration is the probe vibration or the probe has contacted the object.

[0068]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS.

In the invention of this embodiment, the displacement of the contact type probe brought into contact with the surface to be measured from the initial position is detected by the displacement meter 3 as the detecting means, and the measured object is measured based on the output of the displacement meter 3. The present invention relates to a shape measuring method adapted to measure the shape of a surface, a shape measuring device, a computer program for measuring the shape, and a storage medium storing such a computer program. The structure of the contact-type probe used in the invention of the present embodiment is the same as that of the conventional example shown in FIG. Therefore, the contact-type probe will be described by using the contact-type probe described with reference to FIG. 1 as it is, and the description thereof will not be repeated.

The invention of the present embodiment is the above-described shape measuring method, and performs arithmetic processing on the output signal of the displacement meter 3 to obtain a signal that can be regarded as the initial position of the probe. That is the invention. Therefore, in the following, various methods therefor will be described first, and then an apparatus for implementing such a method, software installed in a computer provided in such an apparatus, and a storage for storing such software. Mention the medium.

<First Calculation Processing Method> The stylus probe shown in FIG. 1 is apt to vibrate because of its small sliding resistance and poor damping, and it is difficult to find the initial position in the non-contact state.

Therefore, the weight of the stylus 2 is supported by the spring 7, and the weight of the stylus 2 balances with the spring 7,
Displacement between the stylus 2 and the housing 4 is detected by a displacement gauge 3 as a detecting means (initial signal detecting step, initial signal detecting means, initial signal detecting function), and the detected displacement d
As shown in FIG. 2, z is subjected to arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe (arithmetic step, arithmetic means, arithmetic function). The output dz ^ is the initial position dz _{0 of the} probe.

Here, the contents of the arithmetic processing will be described. The arithmetic processing in the present embodiment is not limited to a single processing, and various kinds of processing can be performed. Therefore, in the following, two types of arithmetic processing, averaging processing and low-pass filtering processing, will be described.

First, the averaging process will be described with reference to FIGS. The averaging process method is a moving averaging process. The displacement dz is sampled at a predetermined sampling time ts as shown in FIG. The sampled dz data is dz (0), dz (1), dz (2),
, Dz (n), dz (n + 1). For example, in the case of a moving average sampled m times, the output dz of the arithmetic processing using the data of dz (0) to dz (m-1)
^ (0) becomes the expression (1).

[0075]

[Equation 1]

Therefore, dz (n) to dz (n + m-
The average value dz ^ (n) using the data of 1) is (2)
It becomes an expression.

[0077]

[Equation 2]

FIG. 4 (a) shows the case where the displacement dz causes the amplitude of the vibration to decay with time, and becomes a stationary microvibration after about 3 seconds. When the attenuation of the probe is poor, minute vibrations as shown in FIG. 4 (a) may remain. FIG. 4B shows a result obtained by sampling such a displacement dz at a predetermined sampling time ts and performing moving average processing a predetermined number of times m. It can be seen that the output dz ^ is delayed because of the averaging process, but the amplitude converges to near 0 after 4 seconds. In this way, the arithmetic processing is performed in real time, and after a predetermined time (in this case, 4 seconds or later) after the effects of steady microvibration and noise of the probe are reduced.
Let dz ^ be the initial position dz _{0 of the} probe.

Next, the low-pass filter processing will be described with reference to FIGS. 3 and 5. Expression (3) is an expression showing the processing content of the analog low-pass filter whose cutoff frequency is ω rad / s. When the analog circuit performs arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe for the detected displacement dz,
An electric circuit equivalent to the formula (3) will be manufactured by an operational amplifier or the like.

[0080]

[Equation 3]

On the other hand, in the present embodiment, as the arithmetic processing, arithmetic processing in the case of digital processing will be described. When the equation (3) is expressed by the state space equation and the output equation, the equations (4) and (5) are obtained.

[0082]

[Equation 4]

[0083]

[Equation 5]

When equations (4) and (5) are discretized with a predetermined sampling time ts, equations (6) and (7) are obtained.

[0085]

[Equation 6]

[0086]

[Equation 7]

As shown in FIG. 3, the displacement dz is sampled at a predetermined sampling interval Ts. The sampled dz data dz (n) is sequentially input to the input u (k) of the equations (6) and (7), processed in real time, and the calculated Y (k) is filtered after dz (n). Let the data be dz ^ (n).

FIG. 5A shows the case where the displacement dz causes the amplitude of the vibration to decay with time, and becomes a stationary microvibration after about 3 seconds. If the probe attenuation is poor,
Small vibrations as shown in FIG. 5A may remain. FIG. 5B shows a result obtained by sampling such a displacement dz at a predetermined sampling time ts and performing the low-pass filter processing by the expressions (6) and (7). Although it changes depending on the cutoff frequency of the low-pass filter, the amplitude after about 3 seconds is sufficiently smaller than the amplitude at the time of input, and it can be seen that the amplitude is a minute amplitude centered on 0. In this way, the calculation processing is performed in real time, and dz ^ after a predetermined time (here, 3 seconds or more) after which the influence of stationary microvibration and noise of the probe is negligible is set to the initial position d of the probe.
Let z ₀ .

Here, when the averaging process and the low-pass filter process are compared, the state variable X (k) before one sampling is stored in the low-pass filter process.
Since only the product-sum calculation of the equations (6) and (7) is performed, it is possible to save resources and reduce the calculation load as compared with the averaging process.

<Second Calculation Processing Method> In the stylus probe shown in FIG. 1, the displacement between the stylus 2 and the housing 4 is detected by the displacement meter 3. In this case, when the displacement gauge 3 is an optical displacement gauge using a focus signal, a capacitance displacement gauge, a displacement transformer type displacement gauge, or the like, noise included in the analog signal is detected in the control system or measured. This may affect the shape data of the surface to be measured. Even when a laser interferometer or the like is used, there is noise such as fluctuation generated by the density distribution of the atmosphere, which may affect the shape data of the control system and the measured surface to be measured.

Therefore, as a second arithmetic processing method, the true sphere 1 at the tip of the stylus 2 is pressed against the surface to be measured, whereby the stylus 2 is moved from the spring force of the spring 7 and the surface to be measured. The displacement gauge 3 as a detection means detects the displacement between the stylus 2 and the housing 4 in a state in which the displacement force is balanced with the reaction force of the
Detect by. Then, as shown in FIG. 2, arithmetic processing is performed on the detected displacement dz to obtain a signal that can be regarded as the initial position of the probe. The output dz ^ is the initial position dz _{0 of the} probe.

Here, as the arithmetic processing, since the same processing as the processing introduced in the first arithmetic processing method is performed,
The description is omitted. The value obtained as a result of such arithmetic processing, that is, the arithmetic result dz ^ for the input dz (n)
(N) is used as the probe displacement.

<Third Arithmetic Processing Method> Since the probe of the stylus type illustrated in FIG. 1 has a small sliding resistance and poor attenuation,
It is easy to vibrate even with a small external force. For this reason, it cannot be said that the vibration of the probe is converged even when the moving stage equipped with the contact type probe is stationary for a certain period of time. If the initial position of the probe is set in a state where the vibration of the probe has not converged to a predetermined value, the displacement from the initial position of the probe has a proportional relationship with the contact load, and thus the contact load may be distorted. Also, if the vibration amplitude is erroneously determined as a contact load, and in that state, switching to control using the displacement gauge output of the probe to control the load,
The probe may collide with the surface to be measured.

Therefore, in the third arithmetic processing method, the displacement between the stylus 2 and the housing 4 is detected by the displacement meter 3, and the predetermined displacement shown in FIG. 6 is applied to the detected displacement dz. Do. When the output e is within the predetermined range, it is determined that the vibration of the probe has converged.

The contents of the arithmetic processing shown in FIG. 6 will be described. The arithmetic processing in the present embodiment is not limited to a single processing, and various kinds of processing can be performed. Therefore, in the following, two types of arithmetic processing, that is, peak hold processing within a specified time interval and processing for obtaining variance will be described.

First, the peak hold process will be described with reference to FIG. The displacement dz is sampled at a predetermined sampling time ts as shown in FIG. The sampled dz data is dz (0), dz (1), d
Let z (2), ..., Dz (n), dz (n + 1). Then, for example, comparing the data of m samplings,
Hold the peak. In this case, the amplitude is assumed to oscillate around 0.

First, the absolute value or square value of each data of dz (0) to dz (m-1) is taken, and the maximum value among them is set as e (0). In the next sampling, dz
The maximum value from (1) to dz (m) is e (1).
In the nth sampling, dz (n) to dz (n + m
The maximum value in -1) is e (n). If this is expressed by an equation, equation (8) is obtained.

[0098]

[Equation 8]

Then, the calculated e (0), ..., e
When (n) is smaller than the predetermined value e _ref, it is determined that the vibration has converged.

Next, the process for obtaining the variance will be described with reference to FIGS. 3 and 7. The displacement dz is sampled at a predetermined sampling time ts as shown in FIG.
The sampled dz data is dz (0), dz
(1), dz (2), ..., dz (n), dz (n + 1)
And Then, for example, the data of m samplings is used to obtain the unbiased variance of dz.

[0102] Here, an average value of dz (0) dz (m- 1) from ^dz - When (0), dz from dz (n)
Average of (n + m-1) is ^dz - (n), and the expressed this in the formula, the equation (9).

[0102]

[Equation 9]

The unbiased variance σ ² (n) at this time is (1
Equation (0) is obtained.

[0104]

[Equation 10]

Then, as shown in equation (11), the value of the unbiased variance σ ² (n) is set to e (n).

[0106]

[Equation 11]

Thus, the calculated e (0), ..., e
When (n) is smaller than the predetermined value e _ref, it is determined that the vibration has converged.

FIG. 7 shows a third arithmetic processing method for the same input dz as in FIG. 4 (a) or FIG. 5 (a).
7 is a graph showing the result of the arithmetic processing shown in FIG. As shown in the graph of FIG. 7, it can be seen that the unbiased variance σ ² = e decreases rapidly as the probe vibrations converge in the direction of time. Therefore, this value e is a predetermined value e _r
When it is smaller than _ef, it is determined that the vibration has converged. In FIG. 7, it is possible to determine whether or not convergence has occurred by setting a convergence value of e _ref = 0.01.

<Data acquisition cycle or calculation cycle> Here,
In each of the arithmetic processing methods described above, the arithmetic processing is performed on the output signal of the displacement meter 3 to obtain a signal that can be regarded as the initial position of the probe. In such arithmetic processing, it is necessary to determine the data acquisition period or the arithmetic period for obtaining the output signal of the displacement meter 3.

Therefore, the first data acquisition cycle or calculation cycle and the second data acquisition cycle or calculation cycle will be introduced below regarding such data acquisition cycle or calculation cycle.

1. First Data Acquisition Cycle or Calculation Cycle The first data acquisition cycle or calculation cycle will be described with reference to FIGS. 2 to 6 and FIGS. 8 to 10.

The predetermined time interval T used in the arithmetic processing shown in FIG. 2 or FIG. 6 is represented by the equation (12) when expressed from the sampling time ts and the sampling number m used in the arithmetic.

[0113]

[Equation 12]

In the first data acquisition cycle or calculation cycle,
As shown in FIG. 8, the predetermined time interval T represented by the equation (12) is set to be equal to or greater than the mechanical resonance period T _p which is the reciprocal of the mechanical resonance frequency f _p of the probe.

Here, an example will be described in which the data acquisition cycle or the calculation cycle of the example adopting the averaging processing described as the first calculation processing method is the first data acquisition cycle or the calculation cycle. The averaging process described in the first arithmetic processing method is
This is a moving averaging process for averaging while moving a predetermined time interval T.

In FIG. 9, the sampling period Ts is constant,
9 is a graph showing a result of performing moving averaging processing by changing the time interval T for averaging by changing the sampling number m. Input values are shown in Fig. 4 (a) or Fig. 5
The same value as in (a) was set to dz.

As shown in the graph of FIG. 9, when the time interval T is 1 cycle to 4 cycles, the amplitude of the signal can be reduced by the moving averaging process. On the other hand, the time interval T
It can be seen that the noise component is removed, but the amplitude of the mechanical resonance frequency f _p is not reduced when the period is 0.5 cycle.

Next, an example will be described in which the data acquisition cycle or the calculation cycle of the example in which the processing for obtaining the variance described as the third calculation processing method is adopted is the first data acquisition cycle or the calculation cycle. The process of obtaining the variance described in the third arithmetic processing method is a process of calculating the unbiased variance while moving the predetermined time interval T.

FIG. 10 is a graph showing the calculation results when the sampling interval Ts is constant and the time interval T for obtaining the unbiased variance is changed by changing the sampling number m. The input value is set to dz, which is the same value as in FIG. 4 (a) or FIG. 5 (a).

As shown in the graph of FIG. 10, the time interval T
In the case of 1 cycle to 4 cycles, the longer the cycle is, the faster the convergence time is, and the vibration is not oscillatory. However, within this range, there is no problem in the criterion for determining the vibration convergence. On the other hand, if the time interval T is set to 0.5 cycle, a large amplitude is generated, and it cannot be used as a reference for determining the convergence of vibration.

2. Second Data Acquisition Cycle or Calculation Cycle The second data acquisition cycle or calculation cycle will be described with reference to FIGS. 2, 6 and 11.

Assuming that the predetermined time interval T used in the arithmetic processing shown in FIG. 2 or FIG. 6 is the number of times of sampling m within the predetermined time in the sampling time ts, the relationship is (1
It becomes as shown in the equation (2). Here, the predetermined time interval T
Is considered to be a predetermined value larger than the cycle of mechanical resonance.
Therefore, the sampling number m is the sampling time ts
Determined by

In the second data acquisition period or calculation period,
The sampling time ts is set to be less than 1/2 of the vibration cycle which is the reciprocal of the mechanical resonance frequency of the probe. In other words,
According to the sampling theorem, it is necessary to sample at more than twice the frequency you want to measure.
/ 2 becomes the Nyquist frequency. That is, the second data acquisition period or calculation period is to select the sampling time ts so that the mechanical resonance frequency of the probe is less than the Nyquist frequency of the sampling frequency 1 / ts.

FIG. 11 shows that the sampling time ts is 1/10, 1/4, 1/3, 1/2 of the cycle of mechanical resonance in the probe while the predetermined time interval T of the arithmetic processing is constant.
It is a graph which shows the result at the time of changing. The input value is
The same value as in FIG. 4A or FIG. 5A was set to dz.

As shown in the graph of FIG. 11, the actual input signal contains high-frequency components such as noise, and
It can be seen that due to the phase difference, correct sampling cannot be performed in the 1/2 cycle which is the sampling limit (Nyquist frequency).

<Application of Arithmetic Processing Method> The configuration and basic operation of the shape measuring apparatus equipped with the probe of the stylus type shown in FIG. 1 are as described in the conventional example. Here, a case where a stylus probe is mounted on a moving stage that moves up and down in the direction of gravity will be described as an example.

The contact load when measuring the shape is the stylus 2.
And the displacement dz of the spring 7 supporting the stylus 2. Therefore, it is necessary to find the initial position dz _{0 at} which the stylus 2 having the weight m and the support spring 7 having the spring constant k _p balance the gravity m · g. When this is expressed by a formula, it becomes as shown in formula (13).

[0128]

[Equation 13]

The contact load f _c is given by the equation (14).

[0130]

[Equation 14]

However, in the stylus probe of the type described in the present embodiment, it is difficult to find the initial position dz ₀ because the stylus 2 easily vibrates. Therefore, in the present embodiment, it is determined by the above-described third calculation method that the vibration of the probe has converged, and the probe position at that time, that is, the initial position dz ₀ of the probe is determined by the above-described first operation.
Alternatively, it is detected using the second calculation method.

Here, when executing the third arithmetic processing, a predetermined value used for determining whether or not the vibration of the probe has converged is set according to the accuracy of the contact load and the time until the start of measurement. As an example, if the accuracy of the contact load is desired to be high, the setting value is strict, and if the convergence determination is fast and the time to start the measurement is short, the set value is loosened.

<Shape Measuring Device for Carrying Out the Shape Measuring Method> Here, a device capable of carrying out each of the arithmetic processing methods described above will be described.

The contact type probe 101 is held so as to come into contact with the measured surface 103 mounted on the measured object mounting jig 102.
1 and the surface 103 to be measured are movable in the X-axis and Y-axis directions.

An X-axis Y-axis stage 104 is provided as a mechanism for moving the contact type probe 101 and the surface 103 to be measured in the X and Y directions. The X-axis and Y-axis stage 104 moves the object 105 having the surface 103 to be measured in the X-axis and Y-axis directions with respect to the contact type probe 101.

On the other hand, the contact type probe 101 is
It is mounted on a Z-axis stage 106 that is driven so as to move in a direction perpendicular to the X-axis and Y-axis stages 104.

Therefore, when measuring the shape of the surface 103 to be measured, the respective stages 104 and 106 are driven and displaced, whereas the displacement of each of the stages 104 and 106, that is, the contact probe to the surface 103 to be measured. 10
In order to detect the movement locus of No. 1, an X-axis laser length measuring device 107, a Y-axis laser length measuring device 108, and a Z-axis laser length measuring device 109 are mounted on the Z-axis stage 106. . In FIG. 12, reference numeral 110 is a reference mirror for the X-axis laser length measuring instrument 107, 111 is a reference mirror for the Y-axis laser length measuring instrument 108, and 112 is a reference mirror for the Z-axis laser length measuring instrument 109. Further, a Z-axis encoder 113 which is a linear encoder for detecting the position of the Z-axis stage 106 is provided.

In this way, X is applied to the surface 103 to be measured.
The surface to be measured 10 is driven so as to be displaced in the axial and Y-axis directions.
The contact type probe 8 that measures the surface shape of the contact type probe 3 while keeping a constant theoretical distance from the probe 3 is equipped with an optical displacement gauge as a displacement gauge 114 that detects a minute displacement dz.

Next, the operation of the shape measuring apparatus will be described. X
Position detection in the axis and Y-axis directions is performed by a rotary encoder or a linear encoder on a motor shaft (not shown), and the X-axis Y-axis stage 104 is driven by the positioning control system using the value of this position. The position of the Z-axis is detected by the Z-axis encoder 113, and this value is used to drive the Z-axis stage 106 by the positioning control system.

Then, the contact type probe 8 is brought into contact with the measured surface 103 of the measured object 105 mounted on the measured object mounting jig 102, and the Z axis is controlled by the follow-up control using the output of the displacement gauge 114. Displacement meter 11
The output of 4 has a predetermined value. In this Z-axis tracking control state, the X-axis Y-axis stage 104 is driven to displace the object 105 to be measured in the X-axis or Y-axis direction, and the surface to be measured 10 is measured.
3 scan over. The locus at this time is taken as the Z-axis stage 10
The shape measuring principle in the shape measuring apparatus according to the present embodiment is to detect the values by the three-axis laser length measuring devices 107, 108, and 109 on 6 and use the values as the surface shape of the measured surface 103.

Next, FIG. 13 shows a Z-axis control system.

First, the positioning control of the Z-axis stage 106 of the shape measuring apparatus equipped with the contact type probe 101 will be described. The output z _ref of the target position 201 and the output z of the Z-axis encoder 113 fed back are compared by the comparator 202, the compensator 203 performs compensation such as phase compensation, and the current command corresponding to the deviation is sent to the driver 204. put out. The driver 204 sends a motor current corresponding to the current command value to the motor of the Z-axis actuator 205,
The Z-axis stage 106 is driven. Although it does not exist in the actual control calculation loop, disturbance is applied to the Z-axis stage 106 in the form of the comparator 206. The displacement z of the Z-axis stage 106 is detected by the Z-axis encoder 113 and fed back to the comparator 202.

Next, the following control will be described. When switching to the follow-up control, the positioning control is performed to move to the switchable position. At the switchable position, the state detection means 301, which is a state detection calculation unit, converges the probe vibration and detects the initial position dz ₀ based on the output dz of the displacement gauge 114.

After the vibration has been converged and the initial position dz ₀ has been detected, the target position is changed and the contact probe 101 is brought into contact with the surface 103 to be measured of the object 105 to be moved to a position where follow-up control is possible. . After the contact type probe 101 has moved to a position where tracking control can be performed, the mode switching units 208 and 209 are switched according to a signal from the mode setting unit 207 to switch to tracking control using the contact type probe 101.

In the follow-up control, the target load 210 is input to the load-displacement conversion unit 211, and the target displacement dz _ref equivalent to the target load f _pref is calculated using the nominal spring constant k _pnom of the probe support spring. In the calculator 212, the initial position dz ₀ calculated by the state detecting means 301 is added to the target displacement dz _ref to obtain the displacement equivalent to the target load. The displacement equivalent to the target load and the output dz of the displacement gauge 114, which is the displacement of the contact type probe 101 fed back, are compared by the comparator 202, the compensator 203 performs compensation such as phase compensation, and the driver 204 is informed of the deviation equivalent. Issue a current command. The driver 204 supplies a motor current corresponding to the current command value to the motor of the Z-axis actuator 205 to drive the Z-axis stage 106. Although it does not exist in the actual control operation loop, Z
A disturbance and the shape of the measured surface 103 are added to the shaft stage 106.

The actual contact load f _p can be calculated by dividing the initial position dz ₀ by the calculator 213 from the displacement meter output dz and multiplying by the actual spring constant k _p .

Here, in the present embodiment, the above-mentioned various arithmetic processes are executed in the state detecting means 301 which is the state detecting arithmetic unit shown in FIG. Therefore, the state detecting means 301 is a computer included in the shape measuring apparatus, and is composed of a microprocessor including a CPU, a ROM, a RAM (all not shown). The ROM that forms part of such a microprocessor is
A computer program for executing the various arithmetic processes described above is stored, and in this sense, a ROM
Functions as a storage medium that stores a computer program.

However, in carrying out the invention, the storage medium for storing the computer program for executing the above-mentioned various arithmetic processes is not limited to a storage medium such as a ROM for fixedly storing fixed data, but data storage. It may be stored in a possible RAM or the like. In consideration of the distribution of such computer programs, such computer programs may be stored in various magnetic or optical storage media, such portable storage media, and the like. The system may be constructed so as to be distributed by download using a network.

Here, in the shape measuring apparatus according to the present embodiment, as described above, the above-described arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe is applied to the output signal of the displacement meter 3. To do. As described above, the data acquisition cycle or the calculation cycle for obtaining the output signal of the displacement meter 3 is an element that needs to be determined in such calculation processing. Hereinafter, the data acquisition period or the calculation period will be described.

In other words, the data acquisition period or calculation period is the data acquisition sampling period. C
In the shape measuring apparatus of the present embodiment using an arithmetic device such as PU or DSP, in order to keep the data sampling period constant, interrupt arithmetic processing provided in the arithmetic device is generally used. The setting of the interrupt calculation cycle can be realized by writing a predetermined value in the register of the interrupt timer included in the device.

Therefore, in the present embodiment, by changing the set value of the interrupt timer according to a predetermined condition, or by acquiring the data only at a predetermined number of interrupts, the data acquisition sampling period can be freely changed. To do. In this way, by changing the data acquisition sampling period, it is possible to change the band of the filtering process according to the conditions.

Here, the equation (6) designed to give a predetermined response at the predetermined sampling period Ts,
Discretized state variables a _d , b _d , and c represented by equation (7)
_When the step response was simulated using d ₁ and _{d 2} , the results shown in FIG. 14 were obtained. That is, when the state variable is fixed and the sampling period Ts is shortened, the filter band is widened to increase the response (cutoff frequency is increased), and the sampling period Ts is lengthened to narrow the filter band. The response becomes slower (cutoff frequency becomes lower).

Further, in the shape measuring apparatus of the present embodiment, at the position where the contact type probe 101 can be switched to the follow-up control for the surface to be measured 103, the output of the displacement gauge 114 in the state detecting means 301 which is the state detecting arithmetic unit. The convergence of the probe vibration is detected from dz, and the counter of the displacement meter 114 equipped with a counter that counts the displacement value is initialized to the initial position dz ₀ = 0. As the displacement meter 114 having a counter that counts the displacement value, a displacement meter of a system that divides and counts an analog waveform, such as a laser length measuring device, is used. This can eliminate the need for the computing units 212 and 213.

[0154]

According to the first aspect of the present invention, the shape of the surface to be measured is measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. In the measurement method, an initial signal detection step of detecting an output signal from the probe located at an initial position by the detection means, and a signal that can be regarded as the initial position of the probe with respect to the output signal of the detection means. And an arithmetic step for performing arithmetic processing for obtaining the probe, the initial position of the probe can be detected accurately and in a short time only by the arithmetic processing without changing the mechanism of the probe. Also, since it is not necessary to use a damping material such as a viscous fluid in the probe, the mechanism can be simplified, and along with this, it is easy to recycle the material, and when using a viscous fluid. In this way, the environmental load at the time of unavoidable disposal can be eliminated.

According to a second aspect of the present invention, in the shape measuring method according to the first aspect, in the initial signal detecting step, the output signal from the probe that is not in contact with the surface to be measured is detected by the detecting means. Since it is detected by the above-mentioned method, it is possible to detect the initial position of the probe which is in a non-contact state with respect to the measurement surface only by the arithmetic processing without changing the mechanism of the probe.

According to a third aspect of the present invention, in the shape measuring method according to the first aspect, in the initial signal detecting step, the output signal from the probe in contact with the surface to be measured is detected by the detecting means. Since the detection is performed, the initial position of the probe that is in contact with the measurement surface can be detected only by the calculation process without changing the mechanism of the probe.

According to a fourth aspect of the present invention, in the shape measuring method according to the first, second or third aspect, the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe,
Since the averaging process is performed on the output signal of the detecting means within a specified time interval, it is possible to easily obtain a signal that can be regarded as the initial position of the probe.

According to a fifth aspect of the present invention, in the shape measuring method according to the first, second or third aspect, the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe,
Since the low-pass filter processing is performed on the output signal of the detection means, when obtaining a signal that can be regarded as the initial position of the probe, it is possible to reduce the load of the arithmetic processing and the resources for the arithmetic processing.

The invention according to claim 6 is the same as claim 1, 2 or
In the shape measuring method according to 3, 4, or 5, the calculation process for obtaining a signal that can be regarded as the initial position of the probe is performed when the value based on the output signal of the detecting means converges to a specified range. Since it includes the vibration convergence determination process that determines that the probe vibration has converged, it is possible to determine the probe vibration convergence only by the calculation process without changing the probe mechanism. It is possible to make a vibration convergence determination of the probe without depending on, and thus it is possible to correctly determine whether it is probe vibration or whether the probe has contacted the object.

According to a seventh aspect of the present invention, in the shape measuring method according to the sixth aspect, since the value based on the output signal of the detecting means is a peak hold value within a specified time interval, the output signal of the detecting means is When determining that the base value has converged to the specified range, it is possible to reduce the load of the arithmetic processing and the resources for the arithmetic processing.

According to an eighth aspect of the present invention, in the shape measuring method according to the sixth aspect, the value based on the output signal of the detecting means is a variance within a specified time interval, so the value based on the output signal of the detecting means. Is determined to be within the specified range, it is robust against changes in the convergence characteristics due to changes in the probe and spring, changes over time, disturbances, etc.
The accuracy of the determination can be improved.

The invention according to claim 9 is the shape measuring method according to claim 4, 7 or 8, wherein the specified time interval is
Since the interval is equal to or longer than the vibration period represented by the reciprocal of the mechanical resonance frequency of the probe, it is possible to define the specified time interval sufficient to obtain the accuracy of the state detection, and thus improve the accuracy of the state detection. You can

According to a tenth aspect of the present invention, in the shape measuring method according to the fourth, seventh or eighth aspect, the data acquisition period or the calculation period within the specified time interval is represented by the reciprocal of the mechanical resonance frequency of the probe. Since the interval is less than ½ of the vibration cycle to be performed, it is possible to define the specified time interval sufficient to obtain the accuracy of the state detection, and thus the accuracy of the state detection can be improved.

According to the eleventh aspect of the invention, in the shape measuring method according to the tenth aspect, the data acquisition period or the calculation period is made variable, so that a prescribed time interval sufficient to obtain the accuracy of state detection is For example, it can be set according to various conditions.

The invention of the shape measuring method according to claim 12 is
When the vibration convergence determination process according to claim 6, 7 or 8 determines that the vibration of the probe has converged, the calculation step according to claim 1, 2, 3, 4 or 5 is performed to obtain Since this value is set to the initial position of the probe, the error due to the vibration of the probe can be reduced and the initial position of the probe can be calculated with high accuracy. Since the detection can be performed, the contact load can be set with high accuracy, and for example, the shape can be measured with high accuracy without damaging the plastic lens or the mold.

According to a thirteenth aspect of the present invention, the shape measuring device is adapted to measure the shape of the surface to be measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. In order to obtain a signal that can be regarded as the initial position of the probe with respect to the output signal of the detection means and the initial signal detection means for detecting the output signal from the probe located at the initial position by the detection means. And an arithmetic means for performing the arithmetic processing, the initial position of the probe can be accurately detected in a short time only by the arithmetic processing without changing the mechanism of the probe. Also, since it is not necessary to use a damping material such as a viscous fluid in the probe, the mechanism can be simplified, and along with this, it is easy to recycle the material, and when using a viscous fluid. In this way, the environmental load at the time of unavoidable disposal can be eliminated.

According to a fourteenth aspect of the present invention, in the shape measuring apparatus according to the thirteenth aspect, the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe is performed based on a value based on the output signal of the detecting means. Since it includes a vibration convergence determination process that determines that the vibration of the probe has converged when it converges within a specified range, it is possible to determine the convergence of the vibration of the probe only by the calculation process without changing the mechanism of the probe. .

According to the fifteenth aspect of the invention, in the shape measuring apparatus according to the fourteenth aspect, when it is determined that the vibration of the probe has converged, the detecting means is initialized, so that an error due to the vibration of the probe is caused. When the initial position of the probe is calculated after reducing the above, the calculation process can be facilitated because the detection means is initialized.

According to a sixteenth aspect of the present invention, when the vibration convergence determination process according to the fourteenth or fifteenth aspect determines that the vibration of the probe has converged, the arithmetic process according to the thirteenth aspect is executed. Since the obtained value is set to the initial position of the probe, the error due to the vibration of the probe can be reduced, and the initial position of the probe can be calculated with high accuracy. Since the accuracy can be detected, the contact load can be set with high accuracy, and for example, the shape can be measured with high accuracy without damaging the plastic lens or the mold.

According to a seventeenth aspect of the present invention, there is provided a storage medium storing a computer program, wherein a displacement of a contact type probe brought into contact with a surface to be measured from an initial position is detected by a detecting means to determine the shape of the surface to be measured. Installed on a computer equipped with a shape measuring device that is designed to measure,
This computer is provided with an initial signal detection function of detecting the output signal from the probe located at the initial position by the detection means, and a signal that can be regarded as the initial position of the probe with respect to the output signal of the detection means. Since the calculation function that performs the calculation process for obtaining is executed,
The initial position of the probe can be detected accurately and in a short time only by the arithmetic processing without changing the mechanism of the probe. Also, since it is not necessary to use a damping material such as a viscous fluid in the probe, the mechanism can be simplified, and along with this, it is easy to recycle the material, and when using a viscous fluid. In this way, the environmental load at the time of unavoidable disposal can be eliminated.

According to an eighteenth aspect of the present invention, in the storage medium according to the seventeenth aspect, a value based on the output signal of the detecting means is specified for the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe. Since it includes a vibration convergence determination process that determines that the vibration of the probe has converged when it converges to the range of, without changing the mechanism of the probe,
It is possible to determine the convergence of the vibration of the probe only by calculation processing, and thus it is possible to determine the convergence of the vibration of the probe without depending on the vibration damping performance of the probe. It is possible to correctly determine whether or not the object is touched.

According to a nineteenth aspect of the invention of a computer program, the displacement of the contact type probe brought into contact with the surface to be measured from the initial position is detected by the detecting means to measure the shape of the surface to be measured. The probe is installed in a computer included in the shape measuring device, and the computer has an initial signal detection function of detecting an output signal from the probe located at an initial position by the detection unit, and the probe with respect to the output signal of the detection unit. The calculation function that performs a calculation process to obtain a signal that can be regarded as the initial position of the probe is executed, and the probe initial position can be accurately and quickly measured only by the calculation process without changing the probe mechanism. Can be detected. Also, since it is not necessary to use a damping material such as a viscous fluid in the probe, the mechanism can be simplified, and along with this, it is easy to recycle the material, and when using a viscous fluid. In this way, the environmental load at the time of unavoidable disposal can be eliminated.

According to a twentieth aspect of the present invention, in the computer program according to the nineteenth aspect, a value based on the output signal of the detecting means is specified for the arithmetic processing for obtaining a signal that can be regarded as the initial position of the probe. Since it includes a vibration convergence determination process for determining that the vibration of the probe has converged when it converges to the range of, the convergence of the vibration of the probe can be determined only by the calculation process without changing the mechanism of the probe, With this, it is possible to determine the vibration convergence of the probe without depending on the vibration damping performance of the probe.
It is possible to correctly determine whether the probe has contacted the object.

According to a twenty-first aspect of the invention, the shape measuring method is adapted to measure the shape of the surface to be measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. In the initial signal detection step of detecting the output signal from the probe located at the initial position by the detecting means, the vibration of the probe converges when the value based on the output signal of the detecting means converges to a specified range. It is possible to determine the convergence of the vibration of the probe only by the arithmetic processing without changing the mechanism of the probe, and to depend on the vibration damping performance of the probe. It is possible to determine the vibration convergence of the probe without doing so. Therefore, whether the vibration of the probe or the contact of the probe with the object It can be correctly determined.

According to a twenty-second aspect of the present invention, the shape measuring device is adapted to measure the shape of the surface to be measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. In, initial signal detection means for detecting the output signal from the probe located at the initial position by the detection means, and vibration of the probe converges when the value based on the output signal of the detection means converges to a specified range. Means for performing a vibration convergence determination process for determining that
Since it is equipped with, without changing the mechanism of the probe,
It is possible to determine the convergence of the vibration of the probe only by calculation processing, and thus it is possible to determine the convergence of the vibration of the probe without depending on the vibration damping performance of the probe. It is possible to correctly determine whether or not the object is touched.

In the invention of the storage medium according to claim 23, the displacement of the contact type probe brought into contact with the surface to be measured from the initial position is detected by the detecting means to measure the shape of the surface to be measured. It is installed in a computer included in the shape measuring device, and an initial signal detection function of detecting an output signal from the probe located at an initial position by the detection means and a value based on the output signal of the detection means are defined in the computer. A function for performing a vibration convergence determination process for determining that the vibration of the probe has converged when it converges to a range, and a computer program for executing the function are stored, so that the vibration of the probe can be converged without changing the mechanism of the probe. It can be determined only by calculation processing, which allows the probe to be used without depending on the vibration damping performance of the probe. Can be the vibration convergence determination, therefore, whether a probe vibration, the probe can be determined whether the contact with the object correctly.

According to a twenty-fourth aspect of the invention of a computer program, the displacement of the contact type probe brought into contact with the surface to be measured from the initial position is detected by the detecting means to measure the shape of the surface to be measured. It is installed in a computer included in the shape measuring device, and an initial signal detection function of detecting an output signal from the probe located at an initial position by the detection means and a value based on the output signal of the detection means are defined in the computer. The function that performs the vibration convergence determination process that determines that the vibration of the probe has converged when it converges to the range is executed, so that the convergence of the probe vibration is determined by only the calculation process without changing the probe mechanism. This makes it possible to judge the vibration convergence of the probe without depending on the vibration damping performance of the probe. It can, therefore, whether a probe vibration, the probe can be determined whether the contact with the object correctly.

[Brief description of drawings]

FIG. 1 is a vertical side view of a contact probe.

FIG. 2 is a schematic diagram showing how an arithmetic process is performed to obtain a signal that can be regarded as an initial position of a probe.

FIG. 3 is a graph illustrating a sampling period of an output signal of a contact probe.

FIG. 4 is a simulation graph showing how the output signal of the contact type probe is attenuated in association with the result of the moving averaging process.

FIG. 5 is a simulation graph showing how the output signal of the contact-type probe is attenuated in association with the result of the low-pass filter processing.

FIG. 6 is a schematic diagram showing how an arithmetic process is performed to obtain a signal that can be regarded as an initial position of a probe.

FIG. 7 is a simulation graph showing a result of a calculation process for determining vibration convergence for an output signal of a contact probe.

FIG. 8 is a graph illustrating a sampling period of an output signal of a contact probe.

FIG. 9 is a simulation graph showing a result of performing moving averaging processing by changing a sampling interval and changing a averaging time interval with a constant sampling period.

FIG. 10 is a simulation graph showing a calculation result in which the sampling cycle is constant and the time interval for obtaining the unbiased variance is changed by changing the number of times of sampling.

FIG. 11 is a diagram showing a case where a predetermined time interval of arithmetic processing is constant,
It is a graph of simulation which shows a result when changing the sampling time to 1/10, 1/4, 1/3, and 1/2 of the cycle of mechanical resonance in the probe.

FIG. 12 is a schematic view showing a structure of a shape measuring device.

FIG. 13 is a block diagram showing a Z-axis control system.

FIG. 14 is a simulation graph showing a result of performing a step response simulation using a plurality of discretized state variables designed to have a predetermined response at a predetermined sampling period.

[Explanation of symbols]

3 Detection means (displacement meter) 101 probe (contact type probe) 103 surface to be measured

Claims (24)

[Claims] 1. A shape measuring method in which a displacement of a contact type probe brought into contact with a surface to be measured from an initial position is detected by a detecting means to measure the shape of the surface to be measured. An initial signal detecting step of detecting an output signal from the probe by the detecting means, and an operation for performing an arithmetic process for obtaining a signal that can be regarded as an initial position of the probe with respect to the output signal of the detecting means. A shape measuring method, comprising: 2. The shape measuring method according to claim 1, wherein in the initial signal detecting step, the detecting means detects an output signal from the probe which is in a non-contact state with the surface to be measured. . 3. The shape measuring method according to claim 1, wherein the detecting step detects the output signal from the probe which is in contact with the surface to be measured in the initial signal detecting step. 4. An arithmetic process for obtaining a signal that can be regarded as an initial position of the probe is an averaging process for an output signal of the detecting means within a specified time interval. 2. The shape measuring method according to 2 or 3. 5. The calculation process for obtaining a signal that can be regarded as the initial position of the probe is a low-pass filter process for the output signal of the detection means. Shape measurement method. 6. The calculation process for obtaining a signal that can be regarded as the initial position of the probe is that the vibration of the probe converges when the value based on the output signal of the detecting means converges within a specified range. The shape measuring method according to claim 1, further comprising a vibration convergence determining process. 7. The value based on the output signal of the detecting means is:
The shape measuring method according to claim 6, wherein the peak hold value is within a specified time interval. 8. The value based on the output signal of the detection means is
The shape measuring method according to claim 6, wherein the dispersion is within a specified time interval. 9. The shape measuring method according to claim 4, wherein the specified time interval is an interval equal to or longer than a vibration period represented by an inverse number of a mechanical resonance frequency of the probe. 10. The data acquisition period or the calculation period within the specified time interval is an interval of less than 1/2 of a vibration period represented by the reciprocal of the mechanical resonance frequency of the probe. The shape measuring method according to Item 4, 7 or 8. 11. The shape measuring method according to claim 10, wherein the data acquisition period or the calculation period is variable. 12. The calculation step according to claim 1, 2, 3, 4 or 5, when it is determined that the vibration of the probe has converged by the vibration convergence determination process according to claim 6, 7, or 8. The shape measurement method is characterized in that the value obtained by executing the above step is set to the initial position of the probe. 13. A shape measuring device configured to measure the shape of the surface to be measured by detecting the displacement from the initial position of a contact type probe brought into contact with the surface to be measured and detecting the shape of the surface to be measured. And an initial signal detecting means for detecting an output signal from the probe by the detecting means, and an arithmetic operation for performing an arithmetic process on the output signal of the detecting means to obtain a signal that can be regarded as an initial position of the probe. A shape measuring device comprising: 14. The calculation process for obtaining a signal that can be regarded as the initial position of the probe is that the vibration of the probe converges when a value based on the output signal of the detecting means converges within a prescribed range. The shape measuring device according to claim 13, further comprising a vibration convergence determination process for determining. 15. The shape measuring apparatus according to claim 14, wherein when it is determined that the vibration of the probe has converged, the detecting means is initialized. 16. The value obtained by executing the arithmetic processing according to claim 13 when the vibration convergence determination processing according to claim 14 or 15 determines that the vibration of the probe has converged, A shape measuring device characterized by being set at an initial position of a probe. 17. A computer provided with a shape measuring device configured to measure the shape of the surface to be measured by detecting the displacement of the contact type probe brought into contact with the surface to be measured from the initial position by a detection means. , An initial signal detection function of detecting an output signal from the probe located at an initial position by the detection means, and a signal that can be regarded as an initial position of the probe with respect to the output signal of the detection means. A storage medium that stores a computer program that executes an arithmetic function that performs arithmetic processing for obtaining 18. The calculation process for obtaining a signal that can be regarded as the initial position of the probe is that the vibration of the probe converges when a value based on the output signal of the detecting means converges within a specified range. The storage medium according to claim 17, further comprising a vibration convergence determination process for determining. 19. A computer provided with a shape measuring device configured to measure the shape of the surface to be measured by detecting a displacement of a contact type probe brought into contact with the surface to be measured from an initial position by a detecting means. , An initial signal detection function of detecting the output signal from the probe located at the initial position by the detection means, and a signal that can be regarded as the initial position of the probe with respect to the output signal of the detection means And a computer program for executing a calculation function for performing a calculation process for obtaining. 20. The calculation process for obtaining a signal that can be regarded as the initial position of the probe is that the vibration of the probe converges when the value based on the output signal of the detecting means converges within a specified range. 20. The computer program according to claim 19, further comprising a vibration convergence determination process for determining. 21. A shape measuring method, wherein a displacement of a contact type probe brought into contact with a surface to be measured from an initial position is detected by a detecting means to measure the shape of the surface to be measured. An initial signal detection step of detecting an output signal from the probe by the detection means, and vibration convergence for determining that the vibration of the probe has converged when a value based on the output signal of the detection means converges to a specified range. A shape measuring method comprising: a determining step. 22. A shape measuring device configured to measure the shape of the surface to be measured by detecting the displacement of the contact type probe brought into contact with the surface to be measured from the initial position by a detecting means. Initial signal detection means for detecting the output signal from the probe by the detection means, and vibration convergence for determining that the vibration of the probe has converged when the value based on the output signal of the detection means converges to a specified range. A shape measuring device comprising: a means for performing a determination process. 23. Installed in a computer provided with a shape measuring device configured to measure the shape of the surface to be measured by detecting the displacement from the initial position of the contact type probe brought into contact with the surface to be measured by the detecting means. In this computer, an initial signal detection function of detecting an output signal from the probe located at an initial position by the detection means, and a value of the probe when the value based on the output signal of the detection means converges to a specified range A storage medium that stores a computer program that executes a function of performing vibration convergence determination processing that determines that vibration has converged. 24. Installed in a computer provided with a shape measuring device configured to measure the shape of the surface to be measured by detecting the displacement of the contact type probe brought into contact with the surface to be measured from the initial position by a detection means. In this computer, an initial signal detection function of detecting an output signal from the probe located at an initial position by the detection means, and a value of the probe when the value based on the output signal of the detection means converges to a specified range A computer program that executes a function of performing vibration convergence determination processing for determining that vibration has converged.