JP2001208532A - Method of measuring contact probe of three-dimensional shape measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of measuring a contact probe of a three-dimensional shape measuring apparatus which enables measurement of the radius of curvature of the contact probe easily at a high accuracy. SOLUTION: Measurements are performed by a spherical surface measuring means to obtain a wave front data of a spherical surface standard at a position where the wave the front of a luminous flux hits vertically on the surface of the spherical surface standard, the position of the spherical surface standard when the measurement for the wave front data is done, a focal wave front data when the luminous flux is focused on the top of the spherical surface standard and the position of the spherical surface standard when the measurement for the focal wave front data is done. Then, the radius of curvature of the spherical surface standard is caculated from the data thus obtained and the focal wave front data and the radius of curvature data of the spherical surface standard are transmitted to a three-dimensional shape measuring apparatus to measure the radius of curvature of a contact probe for measuring the three- dimensional shape of an object by scanning the object in contact therewith based on the measurement data obtained by the measurements of the spherical surface standard and the radius of curvature of the spherical surface standard.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type for measuring a three-dimensional shape and a position of a surface of an object to be measured such as a lens, a mold, a molded product or the like having an aspherical surface or a free-form surface with high accuracy. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact probe measuring method for measuring a radius of curvature of a three-dimensional shape measuring device in order to know the measuring accuracy of the contact probe (measuring needle).

[0002]

2. Description of the Related Art In recent optical parts, an aspherical surface is often used for high performance and miniaturization, and the demand for accuracy of the shape is also increasing. For this reason, high accuracy is also required for a three-dimensional shape measuring device that measures the shape of an aspheric lens.

[0003] In this three-dimensional shape measuring apparatus, particularly a contact-type measuring apparatus, a contact probe having a finite diameter is used. The coordinates in contact with the workpiece are different. At this time, the coordinates at the contact point between the contact probe and the measurement work can be obtained from the inclination at the contact point between the contact probe and the measurement work and the radius of the contact probe. There is a problem that shape measurement cannot be performed.

As described above, in the contact type three-dimensional shape measuring apparatus, the contact probe is required to be a true sphere, and therefore, knowing the accurate radius of curvature of the contact probe requires highly accurate measurement of the object to be measured. It is an important factor in measuring.

Conventionally, for such a problem, for example,
As disclosed in Japanese Patent Application Laid-Open No. H10-221053, a concave and convex spherical prototype having the same radius of curvature or a known difference in the radius of curvature is prepared, and the shapes of the two spherical surfaces are changed to the radius of curvature. It is measured using an unknown spherical contact probe, the radius of curvature of the spherical surface formed by the resulting central coordinate sequence is obtained by calculation, and the radius of curvature of the contact probe is calculated from the difference between the two curvature radii. It takes the method of seeking.

[0006]

However, in the above-described conventional method for measuring a contact probe of a three-dimensional shape measuring apparatus, a prototype of a convex surface and a concave surface having a sphericity necessary for calibrating a contact probe is prepared. In addition, each time the contact probe is calibrated, it is necessary to measure two workpiece shapes, a concave surface and a convex surface.

Further, it is difficult to make the radius of curvature of the convex and concave surfaces of the prototype equal, and even if the difference between the radius of curvature of the concave surface and the radius of curvature of the convex surface is obtained, the reproducibility and linearity accuracy in the measurement are not sufficient. However, at least the accuracy required for the contact probe is required, so that there is a problem that the operation is not easy.

Accordingly, the present invention provides a contact probe measuring method for a three-dimensional shape measuring apparatus capable of easily and accurately measuring a radius of curvature of a contact probe in order to solve the above-mentioned conventional problems. The task is to provide.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, when an object to be measured is contacted and scanned with a contact probe and its three-dimensional shape is measured, the contact probe is used. In a contact probe measurement method of a three-dimensional shape measuring device for measuring a radius of curvature using a spherical prototype, using spherical shape measuring means for measuring the surface shape of the spherical prototype by interference fringe measurement, the spherical shape measuring means The wavefront data of the spherical prototype at a position where the wavefront of the luminous flux is perpendicular to the spherical surface of the spherical prototype, the position of the spherical prototype when measuring this wavefront data, and the apex of the spherical prototype After measuring the focal wavefront data at the time of focusing the light flux and the position of the spherical prototype when measuring the focal wavefront data, and calculating the radius of curvature of the spherical prototype from these data, The tertiary And a shape measuring apparatus by the measurement data obtained by measuring the spherical prototype with the contact probe and the radius of curvature of the spherical prototype, is characterized in that calculating the radius of curvature of the contact probe.

According to a second aspect of the present invention, in the first aspect of the present invention, the three-dimensional shape measuring apparatus and the spherical shape measuring means are connected by a network, and the two wavefront data and the calculated spherical surface are measured. The radius of curvature of the prototype is transmitted from the spherical shape measuring means to the three-dimensional shape measuring device, and the radius of curvature of the contact probe is calculated.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a three-dimensional shape measuring device showing an embodiment according to the present invention, FIG. 2 is a schematic configuration diagram of a spherical shape measuring device showing an embodiment according to the present invention, and FIG. FIG. 4 is a block diagram showing an optical system of the spherical shape measuring device of FIG. 2 including a data processing system of the spherical shape measuring device.

FIG. 1 shows the configuration of a three-dimensional shape measuring apparatus. In FIG. 1, reference numeral 103 denotes a contact-type shape measuring probe (contact probe) for measuring the shape of a spherical prototype 104. The surface of the prototype 104 is traced. 10
1 is a Z slide for driving the contact probe 103 in the Z direction (vertical direction in the figure), 102 is the contact probe 10
3 in the X direction together with the Z slide 101 (left-right direction in the figure)
An X slide 106 for driving the X slide 102 is a gantry of the measuring apparatus, and is equipped with a Y slide for driving the X slide 102 in the Y direction (in the drawing, a direction perpendicular to the paper surface).

The amount of movement of the Z slide 101 in the Z direction, the amount of movement of the X slide 102 in the X direction, and the amount of Y movement of the Y slide 106
The direction movement amount is measured by a scale (not shown) such as a laser length measuring device or an optical scale, and the movement amount can be measured. The spherical prototype 104 has a convex shape, but may have a concave shape.

Reference numeral 105 denotes a hiring jig for positioning and fixing the spherical prototype 104 at a predetermined position. 107 is Y
This is an electrical equipment rack equipped with a driver or the like that drives each axis and the Z axis, and an electric system that takes in laser measurement data that measures the amount of movement in the X, Y, and Z axes. 108 is the electrical equipment rack 1
07 is a control computer for instructing a driver for driving each of the Y and Z axes of a driving amount and a driving method.
Reference numeral 109 denotes a computer having a man-machine interface, which has a function of setting design values and measurement procedures necessary for measurement, displaying a measurement result on a monitor, and recording the result in a storage device. ing. In addition, the computer 109 has a communication function, and can exchange data with another computer.
The computer 109 having such a function is, for example, a workstation.

Next, the configuration of a spherical shape measuring device (spherical shape measuring means) for measuring interference fringes will be described with reference to FIG. In the figure, reference numeral 201 denotes a measurement stage on which a measurement target is mounted. Reference numeral 104 denotes a spherical prototype (see FIG. 1) on which an object to be measured is mounted. Measurement stage 20
In order to set the mounted spherical prototype 104,
A biaxial translation drive mechanism for translating the objects to be measured in directions perpendicular to each other in a plane perpendicular to the optical axis, and two tilt axes for tilting the spherical prototype 104 with respect to the optical axis. And a rotation mechanism for rotating the spherical prototype 104 about the optical axis. Reference numeral 203 denotes a collimator lens in use, reference numeral 204 denotes a turning stage for selecting from a plurality of collimator lenses, and reference numeral 205 denotes an automatic hand for replacing the selected collimator lens on the turning stage 204 with a use state. Reference numeral 206 denotes a reference plane and a reference plane stage, each having two tilt axes for tilting the plane with respect to the optical axis. Reference numeral 207 denotes a moving stage for moving the reference plane and the reference plane stage 206 in the optical axis direction (vertical direction in the figure). Reference numeral 208 denotes a column for mounting and supporting the entire apparatus, which is mounted on a vibration isolation table (not shown). Reference numeral 209 denotes a moving stage for moving the measuring stage 201 in the optical axis direction (vertical direction in the figure).
Reference numeral 210 denotes a laser interferometer for laser-measuring the position and orientation of the measurement stage 201, which has three measurement axes for measuring the position and inclination in the optical axis direction. 211 is a work stocker that stores a plurality of measurement objects waiting for measurement,
Reference numeral 212 denotes a work auto hand for transferring a measurement object, and a measurement target of the work stocker 211 is moved to the measurement stage 201.
The work stocker 211 is used to mount a measurement target placed on the work stocker 211 or loaded from outside. 217
By controlling the inside of the apparatus to a vacuum or low-pressure atmosphere in a vacuum chamber surrounding the entire apparatus, errors in phase data of interference fringes and data of a laser length measuring instrument due to air fluctuation are suppressed. 215 is a vacuum sub-chamber, 216 is a gate connecting the vacuum chamber 217 and the vacuum sub-chamber 215, 218 is a gate connecting the outside and the vacuum sub-chamber 215, 213 and 214 are elevators for inputting an object to be measured, and 213 is measured outside. With the object mounted, 214
Indicates a state set in the vacuum sub-chamber 215, respectively. Reference numeral 219 denotes a monitor camera for monitoring when an object to be measured (the spherical prototype 104 in this embodiment) approaches the upper collimator lens 203.

Next, an overall schematic configuration of the spherical shape measuring apparatus including the data processing system will be described with reference to FIG. 2, the same components as those in FIG. 2 are denoted by the same reference numerals. Reference numeral 217 denotes a vacuum chamber; 1002, an electrical equipment rack that collects various electric circuits for controlling data processing and devices; 1003, a control computer; 1004, a workstation; 1005, a measurement computer.

The workstation 1004 assembles a large measurement sequence, instructs the control computer 1003 about the movement of the apparatus, etc., receives measurement data from the measurement computer 1005, performs various data processing, and displays and saves the result. Input or deletion of measurement condition data or the like. The workstation 1004 is connected to a computer other than the present measurement apparatus via a network, and is configured so that measurement data can be read from a personal computer in a next process section or a development department.

The control computer 1003 converts the command sent from the workstation 1004 into the movement of each machine, and sends the movement coordinates of the stage and the like to the motor drive board of the electrical rack 1002. Electrical equipment rack 10
The motor driver 02 is connected to the motor of each drive shaft of the apparatus main body, and moves the shaft. Electrical rack 100
2 incorporates end limit of the measurement stage 201 (see FIG. 2) and various limit switch information of the apparatus main body such as a safety device such as an air pressure sensor of an anti-vibration table. Stop. At the same time, the abnormality information is communicated to the control computer 1003, and the control computer 1003 displays the abnormality and executes abnormality processing. Reference numeral 1006 denotes an operation panel, which has two parallel movement axes and two tilt axes of the measurement stage 201 by manual operation.
By driving the axis, the coarse movement Z axis and the fine movement Z axis, the interference fringes can be manually adjusted. Reference numeral 1008 denotes an interference fringe or monitor for a monitoring camera inside the vacuum chamber 217, and a plurality of monitors are prepared so that a plurality of monitors can be performed at one time.
Reference numeral 1007 denotes a monitoring camera monitor 1008 and an interference fringe image signal switching device. The switching device 1007 is connected to the control computer 1003 through the electrical equipment rack 1002, and can be automatically switched so as to monitor a necessary part by the movement of the device, or can be manually switched to an arbitrary camera. Some signals of the operation panel 1006 are sent to the control computer 1003 through the signal processing board of the electrical rack 1002, and command signals requiring a plurality of processes are processed by the control computer 1003, and the signals are sent to the motor driver board of the electrical rack 1002. Sent. Reference numeral 1005 denotes a measurement computer which captures measurement data.

The control computer 1003 can monitor the status and abnormality of the main body of the apparatus in real time by constantly reading the signal from the electrical equipment rack 1002. The control computer 1003, the workstation 1004, and the measurement computer 1005 can be processed by one computer.

However, as in this embodiment, the control computer 1003 for controlling the apparatus, the measurement computer 1005 for taking in the measurement data, and the workstation 1004 for processing the data are separated, so that the parallel processing of the sequence is possible. This makes it possible to reduce the device tact and monitor the device in real time.

Next, the optical system of the spherical shape measuring apparatus shown in FIG. 2 will be described with reference to FIG. 4 employs a heterodyne interferometry as a measurement principle of the optical system. In FIG. 4, the same members as those in FIGS. 2 and 3 are denoted by the same reference numerals. Reference numeral 2601 denotes a laser for irradiating coherent light;
Is an input / 2 plate, and 2602 is a wavelength separation device for splitting the laser light from 2601 into light of two different wavelengths to make light waves whose polarization planes differ from each other by 90 degrees. The function of the wavelength separation device 2602 that divides the laser light into two wavelength lights and brings the interference of the two light waves into a beat state can be automatically set and canceled from the outside. Reference numeral 2603 denotes a first beam expander, which serves to spread light. 2604,261
Reference numerals 4, 2615, 2616, 2626, and 2612 denote mirrors, and reference numeral 2606 denotes a half mirror, which has a drive unit (not shown) that is inserted into or removed from the optical path. This driving device can be controlled from the control computer 1003. Reference numeral 2607 denotes an optical box for setting the outline of the optical system, which includes a monitor camera. 2
608 is a polarizing beam splitter, 2609 is an input quarter plate,
A second beam expander (not shown) may be inserted between the input / 4 plate 2609 and the collimator lens 203 (see FIG. 2), and the insertion and ejection of the second beam expander are performed by the control computer 1003. It is possible to control. The spherical prototype 104 (see FIG. 2) shows a state in which a surface shape and a radius of curvature are measured, and 206 is a reference surface (see FIG. 2). Reference numeral 2627 denotes a polarization beam splitter, 2628 denotes an image detection device for capturing an interference fringe, 2631 denotes a light detection element for detecting a phase of a reference signal serving as a reference of the interference fringe, and 2629 denotes a phase of the interference fringe. Of the image detector 26
The phase difference distribution of the interference fringes is detected from the surface image signal from 28 and the reference signal from the photodetector 2631. The measurement computer 1005 (see FIG. 3) calculates the wavefront aberration of the spherical prototype 104 from the phase data from the phase meter 2629, and calculates the surface shape data of the spherical prototype 104.

In the above configuration, the laser beam emitted from the laser 2601 has its polarization plane rotated by a half plate 2633 so that the light quantity ratio is optimized, and then the wavelength separation device 2
602, the polarization planes of which are shifted from each other by 90 degrees and have different frequencies.
The light is split into two lights, and the split light enters a polarization beam splitter 2608.

One of the two light waves is reflected by the polarizing beam splitter 2608, becomes circularly polarized by the input quarter plate 2609, passes through the collimator lens 203, and becomes a spherical prototype.
4 is irradiated on the surface. The light applied to the spherical prototype 104 is reflected, returns to the original optical path, and passes through the collimator lens 203.
After that, the light returns to linearly polarized light at the input / 4 plate 2609. At this time, since the polarization plane is rotated by 90 degrees from the state at the time of incidence, the light is transmitted through the polarization beam splitter 2608.

The other of the two separated light waves is
A quarter-wave plate 26 transmitted through the polarizing beam splitter 2608
At 09, the light becomes circularly polarized light, is reflected by the reference surface 206, and returns to the original optical path. The light that has passed through the input / 4 plate 2609 again is 90
The polarization plane becomes a rotated linearly polarized light, is reflected by the polarization beam splitter 2608, and is combined with the light from the spherical prototype 104 described above. The reflection mirror 2606 is inserted at the time of positioning that does not require precision, and the point of light from the spherical prototype 104 and light from the reference surface 206 are converted into an optical box 2607.
Stage 2 is monitored by a monitor camera
01 (see FIG. 2) and reference stage 206 (see FIG. 2)
Rough alignment is performed. When the rough alignment is completed, the mirror 2606 is removed, and enters the polarizing beam splitter 2627 via the mirrors 2614, 2615, 2616, and 2626. Here, the combined two light waves are in an interference state, and one of the lights split by the polarization beam splitter 2627 is reflected and enters the reference signal detecting light detecting element 2631. The other light transmitted through the polarization beam splitter 2627 is transmitted to the image detection device 2628.
Incident on. The image detection device 2628 can read a change in light amount at an arbitrary point on the two-dimensional image designated by a command from the measurement computer 1005, scans the two-dimensionally, and transmits a signal to the phase meter 2629. In the phase meter 2629, the reference signal detecting light detecting element 2631
By detecting the phase difference from the signal from the image detection device 2628 and the signal of each point from the image detection device 2628, phase data representing the surface shape of the spherical prototype 104 is obtained. Measurement computer 1005
Then, the surface shape of the spherical prototype 104 is measured by performing connection of phase data, correction processing, and the like.

Next, a procedure for measuring the surface shape and radius of curvature of the spherical prototype 104 by the above-mentioned spherical shape measuring apparatus will be described with reference to FIGS. 2, 3 and 4.

First, when the spherical prototype 104 is placed on the elevator 213 for charging the object to be measured, the workstation 1
According to the instruction of 004, the work stocker 211 is mounted at an appropriate place. After the temperature of the spherical prototype 104 is sufficiently adjusted in the work stocker 211, the spherical prototype 104 is mounted on the measurement stage 201 by the automatic hand 212 according to a command from the workstation 1004. At the same time that the spherical prototype 104 is mounted on the measurement stage 201, a collimator lens suitable for measuring the spherical prototype 104 is specified from the workstation 1004, and the collimator lens 2
03 is set in a predetermined place. For this purpose, parameter data such as the designed radius of curvature and effective diameter of the spherical prototype 104 is input to the workstation 1004 in advance. This data is used for collimator lens selection and spherical prototype 1
Since only the approximate value of the measurement position 04 is known, no accuracy is required. When the transfer of the spherical prototype 104 to the measurement stage 201 is completed, the measurement stage 201 is moved to the moving stage 209 so that the surface position of the spherical prototype 104 on the measurement stage 201 becomes the focal position of the collimator lens 203.
It is moved in the upper Z-axis direction (optical axis direction). When the movement of the measurement stage 201 is completed and the exchange of the collimator lens 203 is also completed, the operation panel 1006 can be used, and the operation panel 1006 is operated to execute the positioning of the measurement stage 201 and the reference stage 206. At this time,
The monitoring camera monitor 1008 is a switching device 1007
To switch to the interference fringe screen. Spherical prototype 104
When the alignment of the focal reflection position of the collimator lens 203 is completed, the measurement stage 201 moves on the moving stage 209 and stops at a position where the wavefront of the light beam is perpendicular to the surface of the spherical prototype 104. Measurement stage 20
When the movement of 1 is completed, the operation panel 1006 becomes usable, and the operation panel 1006 is operated to execute the positioning of the measurement stage 201. At this time, since the image of the monitor camera 219 is displayed on the monitor next to the interference fringe monitor of the monitor 1008, the positional relationship between the spherical prototype 104 and the collimator lens 203 can be monitored from outside the vacuum chamber 217. Here, the setting at the position where the wavefront of the light beam on the surface of the spherical prototype 104 hits vertically is completed.

The collimator lens 203 and the spherical prototype 10 when the wavefront of the light beam vertically strikes the surface of the spherical prototype 104.
The positional relationship of No. 4 is shown in FIG. When the positioning is completed, press the measurement start switch. The measurement start switch is connected to the operation panel 1006 or the workstation 10
04 is a soft switch. A measurement start command from the measurement start switch is sent to the control computer 1003 to unlock the anti-vibration table, bring it into a state where the anti-vibration effect appears, and stop the water cooling water flowing to each part of the apparatus for temperature control. . Further, the wavelength separation device 260
2 is switched to a two-wave split beat state. Further, the control computer 1003 instructs the measurement computer 1005 to take in the phase data from the phase meter 2629. Workstation 1004 is
The surface shape data of the spherical prototype 104 is received from the measurement computer 1005. At this time, the Z-axis position of the measurement stage 201 is also read from the laser length measuring device 210.

When the measurement is completed, the measurement computer 10
05 transmits a measurement end signal to the control computer 1003, and the control computer 1003 locks the vibration isolation table and restarts the flow of the temperature control water.

The sequence shifts to data processing, in which a system error is removed, a tilt and a defocus amount are calculated, a difference from an ideal wavefront, and a wavefront aberration are calculated. Next, the result of the data processing is displayed on the monitor screen of the workstation 1004. Thus, the acquisition of the surface shape data of the spherical prototype 104, and the measurement of the defocus amount at the position of the measurement stage 201 and the surface shape measurement position are completed.

Next, the spherical prototype 1 on the measuring stage 201
The work stage 201 is moved on the moving stage 209 in the Z direction (optical axis direction) so that the surface of the work stage 04 is at the focal position of the collimator lens 203. Measurement stage 201
Is completed, the operation panel 1006 can be used, and the operation panel 1006 is operated to execute the positioning of the work stage 201 and the reference stage 206. Here, the collimator lens 20 on the surface of the spherical prototype 104
Positioning at the focal reflection position 3 is completed. The positional relationship between the collimator lens 203 and the spherical prototype 104 at a position where the light flux wavefront becomes a focal point reflection on the surface of the spherical prototype 104,
This is shown in FIG.

Next, when the measurement start switch at the focus reflection position is pressed, the measurement start signal is sent to the workstation 1004.
To the control computer 1003. Next, a measurement start command is sent to the control computer 1003 to release the lock of the anti-vibration table so that the anti-vibration effect appears, and to stop the water cooling water flowing to each part of the apparatus for temperature control. Then, the wavelength separation device 2602 is switched to a beat state of two light wave divisions. Further, the control computer 1003 instructs the measurement computer 1005 to take in the phase data from the phase meter 2629. The workstation 1004 acquires the focal reflection position wavefront data of the spherical prototype 104 from the measurement computer 1005. At this time, the position on the Z axis of the measurement stage 201 on the moving stage 209 is also read from the laser length measuring device 210. When the measurement is completed, the measurement computer 100
5 sends a measurement end signal to the control computer 1003, and the control computer 1003 locks the anti-vibration table and restarts the flow of the temperature control water.

The sequence shifts to data processing, in which the system error is removed, the tilt and the amount of defocus are calculated, and the data of the laser length measuring device 210 at the position where the wavefront of the light beam on the upper surface of the spherical prototype 104 is perpendicularly applied and the focal reflection position. Then, the radius of curvature of the spherical prototype 104 is calculated from the difference between the data of the laser length measuring device 210 and the defocus amount of the measurement result at the position where the luminous flux wavefront is perpendicular and the defocus amount of the focal reflection position wavefront data. The difference between the data of the laser length measuring device 210 at the position where the light beam wavefront hits vertically on the upper surface of the spherical prototype 104 and the data of the laser length measuring device 210 at the focal reflection position is shown in FIG.
(D).

As described above, in addition to the position difference data of the difference d, the wavefront data at the position where the light beam wavefront is perpendicular and the wavefront data at the wavefront data at the focal point reflection position are analyzed to determine the alignment error in the optical axis direction. Can be calculated with a high degree of accuracy, and in addition to the mechanical distance of the difference d, a more accurate spherical prototype 10
4 can be calculated.

The data of the laser length measuring device 210 at each position of the measuring stage 201 is measured at three different positions on the measuring stage 201.
01, the pitching and yawing errors caused by moving on the moving stage 209 can be corrected.

As described above, the defocus amount from the wavefront data of the surface shape at the position where the wavefront of the light beam on the upper surface of the spherical prototype 104 hits vertically, the data of three laser length measuring devices 210, the surface shape at the focal point reflection position By using the defocus amount from the wavefront data and the data of the three laser length measuring devices 210, the accurate radius of curvature of the spherical prototype 104 can be obtained.

By transferring the radius of curvature data and the surface shape data of the spherical prototype 104 measured in this way from the workstation 1004 of FIG. 3 to the computer 109 of FIG. 1, the data can be input manually. , It is possible to enter data.

After inputting the radius of curvature data of the spherical prototype 104 into the computer 109, as shown in FIG.
04 is installed on the hiring jig 105 of the three-dimensional shape measuring apparatus. Then, the shape of the spherical prototype 104 is measured by scanning measurement in which the measurement probe 103 is brought into contact with the spherical prototype 104,
The radius of curvature of the measurement probe 103 is obtained from the measurement data. In this case, since the radius of curvature of the spherical prototype 104 is accurately known, the radius of curvature of the measurement probe 103 can be known with high accuracy.

After measuring the radius of curvature of the spherical prototype 104 with the spherical shape measuring apparatus shown in FIGS. 2 and 3,
It is necessary to convey to the three-dimensional shape measuring apparatus of FIG. 1 by some means.

[0040]

As described above, according to the present invention, the spherical shape measuring means for measuring the surface shape of the spherical prototype by interference fringe measurement allows the position where the wavefront of the luminous flux hits perpendicularly to the surface of the spherical prototype. The surface shape wavefront data of the spherical prototype, and the position of the spherical prototype when measuring the surface profile wavefront data, and the focal wavefront data when the light flux is focused on the vertex of the spherical prototype. Measuring the position of the spherical prototype when measuring the focal wavefront data, calculating the radius of curvature of the spherical prototype from these data, and measuring the spherical prototype with a contact probe. Since the radius of curvature of the contact probe is calculated from the measured data and the radius of curvature of the spherical prototype, the radius of curvature of one contact probe can be easily measured (and corrected) with one spherical prototype. When producing spherical prototypes It can be suppressed and production cost.

Further, since the radius of curvature of the spherical prototype is measured by the spherical shape measuring means, highly accurate measurement corresponding to the accuracy required for the contact probe can be performed.

[Brief description of the drawings]

FIG. 1 is a layout diagram of a three-dimensional shape measuring apparatus showing an embodiment according to the present invention.

FIG. 2 is a schematic configuration diagram of a spherical shape measuring apparatus showing an embodiment according to the present invention.

FIG. 3 is an overall schematic configuration diagram including a data processing system of the spherical shape measuring apparatus of FIG. 2;

FIG. 4 is a configuration diagram showing an optical system of the spherical shape measuring device of FIG. 2;

FIG. 5 is an explanatory diagram showing a positional relationship between a collimator lens and a spherical prototype.

[Explanation of symbols]

 101 Z slide 102 X slide 103 Contact probe 104 Spherical prototype 107 Y slide

Continued on front page F term (reference) 2F065 AA46 BB07 CC00 DD06 DD11 DD14 EE00 FF52 FF61 FF67 GG04 JJ03 JJ15 LL12 LL36 LL37 MM03 PP12 QQ13 QQ21 QQ25 QQ31 SS13 2F069 AA53 BB40 CC08 DD15 GG07 GG07 GG07 GG07 GG07 GG07 GG07

Claims (2)

[Claims] 1. A contact probe of a three-dimensional shape measuring device for measuring a radius of curvature of the contact probe by using a spherical prototype when measuring and measuring a three-dimensional shape of the object by contacting and scanning the object with the contact probe. In the measuring method, using a spherical shape measuring means to measure the surface shape of the spherical prototype by interference fringe measurement, by this spherical shape measuring means,
The wavefront data of the spherical prototype at a position where the light flux wavefront is perpendicular to the spherical surface of the spherical prototype, the position of the spherical prototype when measuring this wavefront data, and the light flux at the apex of the spherical prototype. After measuring the focal wavefront data at the time of focusing and the position of the spherical prototype at the time of measuring the focal wavefront data, and calculating the radius of curvature of the spherical prototype from these data, A three-dimensional shape characterized by calculating a radius of curvature of the contact probe from measurement data obtained by measuring the spherical prototype with the contact probe by a three-dimensional shape measuring device and a radius of curvature of the spherical prototype. Contact probe measurement method for measuring equipment. 2. The three-dimensional shape measuring apparatus and the spherical shape measuring means are connected by a network, and the two wavefront data and the calculated radius of curvature data of the spherical prototype are converted into the spherical shape measurement data. 2. The method according to claim 1, wherein a radius of curvature of the contact probe is calculated by transmitting the curvature radius of the contact probe to the three-dimensional shape measuring device.