JP2005326344A - Three-dimensional shape measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional shape measuring method capable of acquiring highly-reliable shape measuring result. <P>SOLUTION: In this three-dimensional shape measuring method, a correction value measuring step for measuring from the direction orthogonal to the rotation axis direction of a measuring object has at least a step for measuring by using the position relation between a holding member 3 of the measuring object 2 and a rotation mechanism 5 as the first relative position, and the second step for measuring by using the second relative position which is different from the first relative position. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a three-dimensional shape measuring method for measuring the surface shape of an object to be measured by scanning a probe on the surface to be measured.

As a three-dimensional shape measuring apparatus having a rotating stage for rotating the object to be measured, a probe scanning the surface to be measured of the object to be measured, and measuring the surface shape of an optical component or a mold, for example, Patent Document 1 is described.
JP 2003-337018 A

  As shown in FIG. 18, the three-dimensional shape measuring apparatus described in Patent Document 1 includes a rotary stage 101, an R-axis stage 102, a Z-axis stage 103, a probe 104, a rotary stage reference mirror 105, and a motion error detection reference mirror 106. A length measuring device 107 is provided. Here, the rotary stage 101 is used for rotating the DUT 100 in the direction of the arrow. The rotation axis of the rotary stage 101 coincides with the rotational symmetry axis of the object 100 to be measured. The R-axis stage 102 is used to move the probe 104 in the radial direction (R direction) of the object 100 to be measured. This moving direction is a direction orthogonal to the rotation axis of the rotary stage 101. The Z-axis stage 103 is used to move the probe 104 in the rotation axis direction (Z direction) of the rotation stage 101. Further, the probe 104 follows the surface shape of the DUT 100. Further, the rotation stage reference mirror 105 is located on the end surface (axial side) and side surface (radial side) of the cylindrical surface shape 108 formed on the rotation stage 101. The motion error detection reference mirror 106 is held so as not to be affected by the motion of the rotary stage 101. Here, the length measuring device 107 measures the relative distance fluctuation between the rotary stage reference mirror 105 and the motion error detection reference mirror 106.

  With the above configuration, the probe 104 is moved on the surface of the object to be measured 100, the three-dimensional shape is measured by the displacement of the probe 104 at that time, and the motion error component generated during the rotation of the rotary stage 101 is detected. The correction is made so as to remove the influence of the motion error component of the rotary stage 101 from the surface shape measurement result of the object 100 to be measured.

By the way, the conventional apparatus has the following problems. That is, in this conventional apparatus, the motion error of the rotary stage is calculated with reference to the rotary stage reference mirror. However, since the rotation stage reference mirror has a shape error, it is necessary to calculate and correct this shape error.
Therefore, in this conventional apparatus, a reference plane and a reference sphere are installed instead of the object to be measured, and the axial side error of the stage reference mirror is determined using the reference plane, and the stage reference mirror radial is determined using the reference sphere. The side shape error is calculated. However, the reference plane and the reference sphere also have a shape error. For this reason, the shape error of the reference plane and the reference sphere is added to the shape error of the rotation stage reference mirror. Therefore, even if the shape error of the rotary stage reference mirror is corrected using the value, the reliability of the calculation result regarding the motion error of the rotary stage is lowered.
For this reason, even if it correct | amends for removing the influence of the motion error component of a rotation stage with respect to the surface shape measurement result of a to-be-measured object, the reliability of a measurement result may become low.

  The present invention has been made in view of the problems of the conventional apparatus as described above, and an object of the present invention is to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result. is there.

  In order to achieve the above object, a three-dimensional shape measurement method according to the present invention performs a shape measurement step of measuring from a rotation axis direction while rotating the object to be measured, and a measurement from a direction orthogonal to the rotation axis direction. A three-dimensional shape measuring method comprising: a correction value measuring step; and a calculation step of obtaining a three-dimensional shape of the object to be measured from the measurement result of the shape measuring step and the measurement result of the correction value measuring step, The value measurement step includes a first sub-step for performing measurement with the positional relationship between the holding member and the rotation mechanism set to the first relative position, and a second for performing measurement with a second relative position different from the first positional relationship. It has at least two substeps.

  In the three-dimensional shape measurement method according to the present invention, the measurement in the correction value measurement step is performed at a predetermined position along the rotation axis, and the position of the holding member in the second positional relationship is the first position. A position obtained by rotating the holding member 180 degrees around the rotation axis from the position of the holding member in the relationship, and the measurement in the first sub-step and the measurement in the second sub-step are accompanied by a time difference. It is characterized by being performed.

  In the three-dimensional shape measurement method according to the present invention, the measurement in the correction value measurement step is performed at two positions including another position, and the another position is along the rotation axis direction from the predetermined position. It is characterized by being a position separated by a predetermined distance.

  In addition, the three-dimensional shape measurement method according to the present invention includes a third sub-step for performing measurement in a third positional relationship different from the first positional relationship and the second positional relationship, and the correction value measuring step Is measured at a predetermined position along the rotation axis, and the position of the holding member in the second positional relationship is from the position of the holding member in the first positional relationship around the rotation axis. Is rotated by Φ degrees, and the position of the holding member in the third positional relationship is rotated by 2Φ degrees around the rotation axis from the position of the holding member in the first positional relationship. The measurement in the first sub-step, the measurement in the second sub-step, and the measurement in the third sub-step are performed with a time difference. It is said.

  Further, the three-dimensional shape measuring method according to the present invention includes a shape measuring step for measuring from the rotation axis direction while rotating the object to be measured, a correction value measuring step for measuring from a direction orthogonal to the rotation axis direction, In the three-dimensional shape measurement method comprising a measurement result of a shape measurement step and a calculation step of obtaining a three-dimensional shape of the object to be measured from the measurement result of the correction value measurement step, the correction value measurement step includes a first direction. And at least a second sub-step for measuring from a second direction different from the first direction, and the measurement in the correction value measuring step is performed at a predetermined level along the rotation axis. The measurement is performed at a position, and the measurement in the first sub-step and the measurement in the second sub-step are performed simultaneously.

  The three-dimensional shape measuring method according to the present invention is characterized in that the first direction and the second direction are parallel to each other and both intersect the rotation axis.

  The three-dimensional shape measurement method according to the present invention may further include a third sub-step in which the correction value measurement step performs measurement from a third direction different from the first direction and the second direction. 1 direction, the second direction, and the third direction all intersect the rotation axis, and the measurement in the first sub-step, the measurement in the second sub-step, and the third sub-step It is characterized by the fact that measurements are made simultaneously.

  In the three-dimensional shape measurement method according to the present invention, the correction value measurement step includes at least a fourth substep in which measurement is performed at different positions along the rotation axis, and the fourth substep includes the first substep and The second sub-step and the third sub-step are performed simultaneously.

  The three-dimensional shape measuring method according to the present invention includes a shape measuring step for measuring from the direction of the rotation axis while rotating the object to be measured, a correction value measuring step for measuring from the same direction as the shape measuring step, and the shape In the three-dimensional shape measurement method comprising a measurement result of the measurement step and a calculation step of obtaining a three-dimensional shape of the object to be measured from the measurement result of the correction value measurement step, the correction value measurement step is performed in the shape measurement step. A peripheral portion of the measurement region is measured, and the measurement in the shape measurement step and the measurement in the correction value measurement step are performed simultaneously.

  The three-dimensional shape measuring method according to the present invention is characterized in that the correction value measuring step measures four positions in the peripheral portion.

  The three-dimensional shape measuring method according to the present invention is characterized in that a roundness shape error and a radial movement error are calculated by the correction value measuring step.

  In the three-dimensional shape measuring method according to the present invention, the measurement at the predetermined position is a position where the holding member is measured.

  Further, the three-dimensional shape measuring method according to the present invention is characterized in that the measurement at the different position is a position at which the rotation mechanism is measured.

According to the present invention, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result. In more detail, it is as follows.
According to the first aspect of the present invention, in order to detect a movement error of the rotation mechanism, a first sub-step for performing measurement with the positional relationship between the holding member and the rotation mechanism as a first relative position; By having a second sub-step for performing measurement at a second relative position different from the positional relationship of 1, the shape error data on the rotation error detection surface of the holding member (jig) installed in the rotation mechanism is used as a reference object. It can be calculated accurately without any. For this reason, it is possible to calculate the motion error of the rotating mechanism during the measurement of the object to be measured using the calculation result. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. it can.

  According to the second aspect of the present invention, when detecting the movement error of the rotation mechanism, the positional relationship between the holding member and the rotation mechanism is rotated 180 degrees around the rotation axis by the holding member from the first relative position. The measurement is performed at each of the second relative positions. Thereby, since the reversal method used for roundness measurement can be used, the shape error data of the rotation error detection surface of the holding member (jig) installed in the rotation mechanism can be accurately calculated without a reference object. . For this reason, it is possible to calculate the motion error of the rotating mechanism during measurement of the object to be measured using the calculation result. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the motion error from the shape measurement result of the object to be measured using the calculated motion error. .

  According to the third aspect of the present invention, not only the rotation error detection surface of the holding member (jig) installed in the rotation mechanism but also the rotation error detection surface of the rotation mechanism when detecting the motion error of the rotation mechanism. Measure at the same time. Thereby, since the improved inversion method used for roundness measurement can be used, the shape error data of the rotation error detection surface of the jig installed in the rotation mechanism can be accurately calculated without a reference object. For this reason, it is possible to calculate the motion error of the rotating mechanism during the measurement of the object to be measured using the calculation result. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. it can.

  According to the fourth aspect of the present invention, when detecting the motion error of the rotation mechanism, by performing the measurement in the first sub-step, the measurement in the second sub-step, and the measurement in the third sub-step, Since the phase difference method used for roundness measurement can be used, the shape error data of the rotation error detection surface of the holding member (jig) installed in the rotation mechanism can be accurately calculated without a reference object. For this reason, it is possible to calculate the motion error of the rotating mechanism during the measurement of the object to be measured using the calculation result. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. it can.

  According to the fifth aspect of the present invention, when detecting the motion error of the rotating mechanism, the measurement in the first sub-step and the second sub-step is performed at the same time and used for roundness measurement. A multi-probe method such as a point method or a three-point method can be used. Therefore, the shape error data of the rotation error detection surface of the holding member (jig) installed in the rotation mechanism and the shape error of the rotation error detection surface of the rotation mechanism can be accurately calculated without a reference object. Further, since measurement can be performed simultaneously with measurement of the shape of the object to be measured, an asynchronous motion error of the rotation mechanism and a displacement due to a change with time can be calculated. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. it can.

  According to the sixth aspect of the present invention, when detecting the motion error of the rotation mechanism, the first detection direction and the second detection direction are parallel and intersect the rotation axis. A two-point method used for roundness measurement can be used. For this reason, the roundness shape error of the motion error detection surface of the holding member (jig) installed in the rotation mechanism and the roundness shape error of the motion error detection surface of the rotation mechanism can be accurately calculated without a reference object. For this reason, it is possible to calculate the motion error of the rotating mechanism during the measurement of the object to be measured using the calculation result. Furthermore, a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the measured object using the calculated radial direction movement error is provided. can do.

  According to the seventh aspect of the present invention, in the invention according to the fifth aspect, when detecting a motion error of the rotation mechanism, a multi-path used in the roundness measurement method is added by adding a third detection direction. A probe method can be used. For this reason, it is possible to accurately calculate the motion error of the rotating mechanism during measurement of the object to be measured without a reference object. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the motion error from the shape measurement result of the object to be measured using the calculated motion error. .

  According to the present invention described in claim 8, in the invention described in claim 7, when detecting a motion error of the rotation mechanism, a roundness is obtained by adding measurement steps at different positions along the rotation axis. A multi-probe method used for measurement can be applied. For this reason, it is possible to calculate a radial motion error and an angular motion error with high reliability without using a calibrated spherical or flat reference object. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. it can.

  According to the ninth aspect of the present invention, when detecting the movement error of the rotation mechanism, the detection axis is arranged in the same direction as the shape measurement step, thereby reducing the movement error in the axial direction of the rotation mechanism without a reference object. It is possible to calculate with high accuracy. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. it can.

  According to the tenth aspect of the present invention, when detecting the motion error of the rotation mechanism, the multi-probe method used for roundness measurement can be used by arranging four position detectors. For this reason, it is possible to accurately calculate a motion error in the axial direction of the rotating mechanism during measurement of the object to be measured without a reference object. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. it can.

  According to the invention described in claim 11, in the invention described in any one of claims 1-8, the correction value measuring step includes the roundness shape error of the rotation error detection surface and the motion of the rotation mechanism. The error (radial direction) can be accurately calculated without a reference object. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. it can.

  According to the twelfth aspect of the present invention, in the invention according to any one of the second, fourth, and fifth aspects, since the measurement at the predetermined position is the holding member, the rotation error detection surface of the holding member is It is possible to accurately measure the roundness shape error. Then, using the calculation result, it is possible to calculate the motion error of the rotating mechanism during the measurement of the object to be measured. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the movement error from the shape measurement result of the object to be measured using the calculated movement error. .

  According to the invention described in claim 13, in the invention described in claim 3 or 5, since the measurement at another position is performed at the position where the rotation mechanism is measured, the trueness of the rotation error detection surface of the rotation mechanism is measured. It is possible to accurately measure the circular shape error and the movement error of the rotation mechanism. Furthermore, it is possible to provide a three-dimensional shape measurement method capable of obtaining a highly reliable shape measurement result by removing the motion error from the shape measurement result of the object to be measured using the calculated motion error. .

Next, embodiments of the present invention will be described with reference to the drawings.
First Embodiment FIG. 1 is an apparatus for carrying out a three-dimensional shape measuring method according to the first embodiment, and is a perspective view schematically showing main parts. FIG. 2 is a block diagram of a processing unit of the apparatus of FIG. FIG. 3 is a flowchart showing the measurement procedure of the first embodiment.
As shown in FIG. 1, the measuring device 12 has a vertical direction as a Z-axis direction and a horizontal direction as an X-axis direction. In this coordinate system, the air spindle 5 is installed on the surface plate 11 with the Z-axis direction as the rotation axis. The object to be measured 2 is disposed on a jig 3 installed on the air spindle 5. P and P ′ are marks of the positions of the jig 3 and the air spindle 5. The probe 4 is installed on the Z stage 9 and moves following the shape of the surface to be measured of the object 2 to be measured. The Z stage 9 is movably installed on the X stage 7. Accordingly, the probe 4 is movable in the X axis direction and the Z axis direction. The positions of the probe 4 in the X-axis direction and the Z-axis direction are measured by a linear scale 8 provided on the X stage 7 and a linear scale 10 provided on the Z stage 9, respectively. The rotation angle θ of the air spindle 5 is measured by the rotary encoder 6. Further, in order to detect a motion error of the air spindle 5, a position detector 1 having a detection axis in a direction perpendicular to the rotation axis of the air spindle 5 is installed.
In the present apparatus, the detection surface (hereinafter, detected surface) detected by the position detector 1 is the side surface (cylindrical surface) of the jig 3. However, if it is a cylindrical surface other than the air spindle 5, it may be the edge of the object 2 to be measured, for example.

  As shown in FIG. 2, the processing unit includes control means 21, storage means 23, coordinate conversion means 24, and air spindle motion error calculation means 22. This processing unit may be integrated with the measuring apparatus 12 or may be a separate body. The control means 21 controls the entire apparatus, and the storage means 23 stores various data such as shape measurement data. The air spindle motion error calculation means 22 separates the roundness shape error of the side surface of the jig 3 from the radial direction (X-axis direction) motion error of the air spindle 5 based on the measurement data of the position detector 1. Here, the side surface of the jig 3 is a cylindrical surface. Therefore, the roundness shape error is a shape error of the measured cylindrical surface with respect to the ideal cylindrical surface. The coordinate conversion means 24 performs coordinate conversion and correction of the motion error of the air spindle 5 on the shape measurement data.

Next, a specific measurement method will be described with reference to FIG. In this embodiment, first, the jig 3 on which the object to be measured 2 is installed is fixed on the air spindle 5 (step Sl). Here, the roundness shape error of the side surface of the jig 3 is detected by the position detector 1. As a method of detecting the roundness shape error by the position detector 1, an inversion method or a phase difference method used for roundness measurement is used. By using these methods, it is possible to accurately detect the roundness shape error of the side surface (detected surface) of the jig 3 without using the reference surface with guaranteed roundness as the test surface. I can do it. Note that the roundness shape error of the side surface of the jig 3 is a more accurate value since the radial movement error of the air spindle 5 is removed. Further, the detected surface may not be a calibrated spherical surface or flat surface. Alternatively, the roundness may not be guaranteed with respect to the rotation axis. Therefore, it is not necessary to prepare a reference object.
In this embodiment, the step of calculating the roundness shape error of the side surface of the jig 3 is performed before measuring the shape of the object to be measured, but may be performed after measuring the shape of the object to be measured.

Next, a method for calculating the roundness shape error by the inversion method and the phase difference method will be described. First, the inversion method will be described. As shown in FIG. 4A, the air spindle 5 is rotated by the control means 21, and the output of the position detector 1 is stored in the storage means 23 in this state. Here, the signal output by the position detector 1 is as follows.
m (θ) = r (θ) + e _x (θ) (1)
However, θ is 0 to 2π, m (θ) is the output of the position detector 1, r (θ) is the detected surface, here the roundness shape error of the side surface of the jig 3, and e _x (θ) is air This is a movement error of the spindle 5 in the radial direction.

Next, as shown in FIG. 4B, the jig 3 and the position detector 1 are reversed 180 degrees around the rotation axis of the air spindle 5 while the air spindle 5 is fixed. In this state, the air spindle 5 is rotated by the control means 21, and the output of the position detector 1 is stored in the storage means 23 in this state. Here, the signal output by the position detector 1 is as follows.
m ′ (θ) = r (θ) −e _x (θ) (2)
However, θ is 0 to 2π, and m ′ (θ) is an output of the position detector 1.
Using the above formulas (1) and (2), from the output values m (θ) and m ′ (θ), the roundness shape error r (θ) of the detected surface, here, the side surface of the jig 3 And the radial motion error e _x (θ) can be obtained separately. The calculation method is as follows: Document: “Nano-measurement of rotational accuracy by separating shape error and motion error” Journal of Precision Engineering Vol. 67, No. Refer to 7, 2001, p1067 to p1071.

Next, the phase difference method will be described. As shown in FIGS. 5A, 5B, and 5C, the position of the jig 3 is set to ΔΦ (= Shift 2 times by 2π / N). Then, the air spindle 5 is rotated at each position when shifted, and the measurement by the position detector 1 is performed. Here, it is assumed that the phase difference in the shape of the side surface of the jig 3 is ΔΦ. In this case, the output of the position detector 1 in each of the N measurement steps is expressed by Equation (3).
m _i (θ) = r (θ−i △ Φ) + e _x (θ) (3)
Where m (θ) is the output of the position detector 1 and i is the number of measurement steps (1 to N).
Using the above equation (3), the roundness shape error r (θ) and radial motion error e _x (θ) of the surface to be detected, here, the side surface of the jig 3, can be calculated. The calculation method is as follows: Document: “Nano-measurement of rotational accuracy by separating shape error and motion error” Journal of Precision Engineering Vol. 67, No. Refer to 7, 2001, p1067 to p1071.

The calculated roundness shape error r (θ) of the side surface of the jig 3 is stored in the storage means 23 (step S2).
Next, the device under test 2 is rotated by the air spindle 5 based on the control of the control means 21. In this state, the probe 4 is moved in the Z-axis direction by the Z stage 9 in accordance with the shape change of the measurement surface of the DUT 2. At the same time, the probe 4 is moved in the X-axis direction by the X stage 7 at the same time. At this time, the position of the probe 4 on the X axis and the position of the probe 4 on the Z axis (hereinafter referred to as (x ₁ , z ₁ )) are measured by the linear encoders 8 and 10. Further, the rotation angle (θ) of the air spindle 5 is measured by the rotary encoder 6. At the same time, the output (E) of the position detector 1 is also measured. In this way, the shape measurement data (x ₁ , z ₁ , θ, E) of the DUT 2 is acquired as point sequence data and stored in the storage means 23 (step S3).

Next, the coordinate measurement unit 24 corrects the shape measurement data acquired in step S3 using the roundness shape error of the side surface of the jig 3 acquired in step S2. That is, the shape measurement data (x ₂ , z ₂ , θ) from which the radial movement error e _x (θ) of the air spindle 5 is removed is calculated using the following calculation formula.
e _x (θ) = E−r (θ) (4)
x ₂ = x ₁ −e _x (θ), z ₂ = z ₁ , θ = θ (5)
Shape measurement data (x ₂ , z ₂ , θ) is obtained from the above equations (4) and (5) (step S4).

  As described above, in the first embodiment, the position detector 1 is attached in a direction orthogonal to the rotation axis of the air spindle 5 and the side surface (surface other than the air spindle 5) of the jig 3 is reversed or phase-differenced. It is measured by. By doing in this way, the roundness shape error of the side surface of the jig 3 can be detected with high accuracy. Therefore, it is possible to accurately calculate the radial movement error of the air spindle 5 that occurs during measurement. As a result, since this movement error can be removed from the shape measurement data of the DUT 2, shape measurement data with high reliability can be acquired in the first embodiment.

FIG. 6 is a modification. In this modification, in order to calculate the motion error of the air spindle 5, an improved inversion method used for roundness measurement is used. This modification differs from the first embodiment in that a position detector B is added in addition to the position detector A that measures the displacement of the side surface of the jig 3. This position detector B is for measuring the displacement of the side surface (cylindrical surface) of the air spindle 5. Similarly to the position detector A, the position detector B is installed such that the detection shaft is positioned in a direction orthogonal to the rotation axis of the air spindle 5. With this arrangement, the air spindle 5 is arranged at a position where the side surface (cylindrical surface) can be measured.
With such a configuration, it is possible to detect a radial movement error of the air spindle 5 without reproducibility. Therefore, when calculating the roundness shape error of the side surface (cylindrical surface) of the jig 3, such an error can be eliminated, and a highly reliable result can be obtained.

Next, a roundness shape error calculation method, a shape measurement method, and a shape measurement data correction method for a surface to be detected by an improved inversion method will be described.
FIG. 7 is a principle diagram for calculating the roundness shape error of the side surface of the jig 3 using the improved inversion method. FIG. 8 is a flowchart of shape measurement using the improved inversion method. As shown in FIG. 7, in the improved inversion method, the displacement of the side surface (cylindrical surface) of the air spindle 5 is also measured. Therefore, in this configuration, the position detector B is arranged so that the detection axis is positioned in a direction orthogonal to the rotation axis. Further, since the processing unit used in the measurement apparatus 12 ′ is the same as the processing unit of the first embodiment, description thereof is omitted.

Hereinafter, a specific measurement method will be described with reference to FIG. Step Sll is the same as Step S1 in the first embodiment, and thus the description thereof is omitted. Next, the roundness shape error of the side surface (cylindrical surface) of the jig 3 is calculated by the position detector A. The roundness shape error on the side surface of the jig 3 is calculated according to the following procedure. First, as shown in FIG. 7A, the air spindle 5 is rotated by the control means 21, and the outputs of the position detector A and the position detector B are stored in the storage means 23 in this state. Here, the signals output by the position detector A and the position detector B are as follows.
m _A (θ) = r _A (θ) + e _x (θ), m _B (θ) = r _B (θ) + e _x (θ) (6-1)
However, θ is 0 to 2π, m _A (θ) is the output of the position detector A, r _A (θ) is the roundness error of the detected surface, here the side surface (cylindrical surface) of the jig 3 , E _x (θ) is a radial motion error. M _B (θ) is the output of the position detector B, and r _B (θ) is the roundness shape error of the side surface (cylindrical surface) of the air spindle 5.

Next, as shown in FIG. 7B, only the jig 3 and the position detector A are reversed 180 degrees while the air spindle 5 is fixed. In this state, the air spindle 5 is rotated by the control means 21. And the output of the position detector A and the position detector B is preserve | saved in the memory | storage means 23, rotating. Here, the signals output by the position detector A and the position detector B are as follows.
m ′ _A (θ) = r _A (θ) −e ′ _x (θ), m ′ _B (θ) = r _B (θ) + e ′ _x (θ) (6-2)
However, θ is 0 to 2π, m ′ _A (θ) is the output of the position detector A, r _A (θ) is the detected surface, here the roundness shape error of the side surface (cylindrical surface) of the jig 3, e ′ _x (θ) is the radial motion error, m ′ _B (θ) is the output of the position detector B, and r _B (θ) is the roundness shape error of the side surface (cylindrical surface) of the air spindle 5. .

From the output values m _A (θ), m _B (θ) and m ′ _A (θ), m ′ _B (θ), as shown in the above equations (6-1) and (6-2), the air It is possible to eliminate a radial motion error that the spindle 5 does not reproduce. That is, to calculate only the roundness shape error r _B roundness shape error r _A (theta) and air spindle 5 of side surfaces of the jig 3 (cylindrical surface) (theta), stored in the storage means 23 (Step S12). The calculation method is as follows: Document: “Nano-measurement of rotational accuracy by separating shape error and motion error” Journal of Precision Engineering Vol. 67, No. Refer to 7, 2001, p1067 to p1071.

Next, the device under test 2 is rotated by the air spindle 5 based on the control of the control means 21. In this state, the probe 4 is moved in the Z-axis direction by the Z stage 9 in accordance with the change in the shape of the measurement surface of the DUT 2. At the same time, the probe 4 is moved in the X-axis direction by the X stage 7. At this time, the position of the probe 4 on the X axis and the position of the probe 4 on the Z axis (hereinafter referred to as (x ₁ , z ₁ )) are measured by the linear encoders 8 and 10. Further, the rotation angle (θ) of the air spindle 5 is measured by the rotary encoder 6. At the same time, the position detector A also measures the displacement (E _A ) of the side surface of the jig 3. In this way, the measurement data (x ₁ , z ₁ , θ, E _A ) is converted into point sequence data by combining the shape measurement data of the measurement surface of the DUT 2 and the displacement measurement result of the side surface of the jig 3. And is stored in the storage means 23.

Next, the roundness shape error of the side surface (cylindrical surface) of the jig 3 acquired in step S12 from the measurement data (x ₁ , z ₁ , θ, E _A ) acquired in step S13 by the coordinate conversion unit 24. r _A (θ) is removed, and the radial motion error e _x (θ) of the air spindle 5 is calculated. The calculation formula is shown below.
e _x (θ) = E _A −r _A (θ) (7)

Further, the shape measurement data (x ₂ , z ₂ , θ) from which the motion error is removed is calculated using the radial motion error e _X (θ) calculated by the equation (7). (Step S14). The calculation formula is shown below.
x ₂ = x ₁ −e _x (θ) z ₂ = z ₁ θ = θ (8)

In step S13, the output of the position detector A is stored when measuring the shape, but the output of the position detector B may be used instead of the output of the position detector A. At this time, the motion error e _x (θ) of the air spindle 5 is calculated using the roundness shape error r _B (θ) of the side surface (cylindrical surface) of the air spindle 5.

  According to the above modification, the roundness shape error of the cylindrical surface can be accurately detected. For this reason, it is possible to calculate the radial movement error of the air spindle 5 during the surface shape measurement using the roundness shape error calculation result. Then, by removing this motion error from the shape measurement data, reliable three-dimensional shape measurement data can be obtained.

  FIG. 9 shows another modification. In this modification, in order to calculate the motion error of the air spindle 5, a two-point method used for roundness measurement is used. Compared with the first embodiment, this modification has a position opposite to the position of the detector A ′ that measures the displacement of the side surface of the jig 3 (a direction rotated 180 degrees) across the rotation axis. The difference is that a position detector B ′ for measuring the displacement of the side surface of the jig 3 is added. Similarly to the position detector A ′, the position detector B ′ is installed so that the detection axis is positioned in a direction orthogonal to the rotation axis of the air spindle 5. With such a configuration, it is possible to detect a movement error in the radial direction of the air spindle 5. Therefore, when calculating the roundness shape error of the side surface (cylindrical surface) of the jig 3, such an error can be eliminated, and a highly reliable result can be obtained.

A method for calculating the roundness shape error of the surface to be detected by the two-point method, a shape measurement method, and a method for correcting the shape measurement data will be described.
FIG. 9 is a principle diagram for calculating the roundness shape error of the side surface of the jig 3 using the two-point method. As shown in FIG. 9, in this configuration, the position detector B ′ is arranged in a direction (a direction rotated by 180 degrees) opposite to the position detector A ′ with respect to the rotation axis. The position detector B ′ is arranged so that the detection axis is positioned in a direction orthogonal to the rotation axis. The processing unit used in the measuring apparatus 12 ″ is the same as that in the first embodiment, and thus the description thereof is omitted. The measuring method is almost the same as that in the first embodiment (FIG. 3). However, since the method of calculating the roundness shape error of the side surface of the jig 3 performed in step S2 of Fig. 3 and the shape measuring method performed in step S3 are characteristic, only steps S2 and S3 will be described. Description of other steps is omitted.

Calculation of the roundness shape error of the side surface of the jig 3 by the two-point method of this modification is performed according to the following procedure.
First, as shown in FIG. 9, the air spindle 5 is rotated by the control means 21. In this state, the outputs of the position detector A ′ and the position detector B ′ are stored in the storage means 23. Here, the signals output by the position detector A ′ and the position detector B ′ are as follows.
m _{A '} (θ) = r (θ) + e _x (θ), m _{B '} (θ) = r (θ−180) − e _x (θ) (9-1)
Where θ is 0 to 2π, m _{A ′} (θ) is the output of the position detector A ′, and r (θ) is the detected surface, roundness shape error of the side surface (cylindrical surface) of jig 3, e _x (θ) is the radial motion error, m _{B '} (θ) is the output of position detector B' It is.

Next, when the difference between m _A (θ) and m _B (θ) is taken to remove the motion error e _x (θ) of the air spindle 5, the differential output m _AB (θ) is as follows.
m _AB (θ) = m _{A ′} (θ) −m _{B ′} (θ) = r (θ) −r (θ-180) (9-2)

Next, with respect to equation (9-2), the roundness shape error r of the side surface of the jig 3 First-order integration is performed on the first derivative m ′ _AB (θ) of (θ) and the calculated m ′ _AB (θ). By doing so, the roundness shape error of the side surface of the jig 3 from which the motion error of the air spindle 5 is removed can be calculated (step S2 ′).

Next, the device under test 2 is rotated by the air spindle 5 based on the control of the control means 21. In this state, the probe 4 is moved in the Z-axis direction by the Z stage 9 in accordance with the shape change of the measurement surface of the DUT 2. At the same time, the probe 4 is moved in the X-axis direction by the X stage 7. Then, the position of the probe 4 on the X axis and the position of the probe 4 on the Z axis (hereinafter (x ₁ , z ₁ )) are measured by the linear encoders 8 and 10. Further, the rotation angle (θ) of the air spindle 4 is measured by the rotary encoder 6. At the same time, the position detector A ′ also measures the displacement (E) of the side surface of the jig 3. In this way, measurement data (x ₁ , z ₁ , θ, E) obtained by combining the shape measurement data of the measurement surface of the DUT 2 and the displacement of the jig 3 is acquired as point sequence data and stored. The information is stored in the means 23 (step S3 ′).

  According to the above-described modification, the roundness shape error of the side surface of the jig 3 can be detected with high accuracy. For this reason, it is possible to calculate the radial motion error of the air spindle 5 during the surface shape measurement using the calculation result of the roundness shape error. Then, by removing this error from the shape measurement data, reliable three-dimensional shape measurement data can be acquired.

Second Embodiment FIG. 10 is an apparatus for carrying out the three-dimensional shape measuring method according to the second embodiment, and is a perspective view schematically showing the main part. FIG. 11 is a flowchart showing the measurement procedure of the second embodiment.
The second embodiment will be described below with reference to FIGS. Also in this embodiment, the vertical direction is the Z-axis direction and the horizontal direction is the X-axis direction, as in the first embodiment. In this coordinate system, the air spindle 5 is installed on the surface plate 11 with the Z-axis direction as the rotation axis. Further, the DUT 2 is disposed on a jig 3 installed on the air spindle 5. Further, the three position detectors (A1, A2, A3) are installed such that the detection axes are located at different angular positions in the θ direction within the plane in which the detection axes are orthogonal to the rotation axis.

Compared with the first embodiment, the measuring device 13 of the present embodiment measures roundness as means for calculating the radial motion error of the air spindle 5 during the measurement of the shape of the surface to be measured 2 of the device under test 2. It is characterized by using the multi-probe method used in
In this embodiment, a detection surface (hereinafter referred to as a detection surface) detected by the position detectors (A1, A2, A3) is a side surface (cylindrical surface) of the jig 3. The detected surface may be, for example, the edge of the object to be measured 2 or the side surface (cylindrical surface) of the air spindle 5 main body. Other configurations are the same as those of the first embodiment. Further, since the processing unit used in the measurement apparatus 13 is the same as that of the first embodiment, the description thereof is omitted.

Next, a specific measurement method of the second embodiment will be described with reference to FIG.
First, step S21 is the same as step S1 in the first embodiment, and a description thereof will be omitted. Step S22 is a process for measuring the shape of the DUT 2. In this shape measuring step, the device under test 2 is rotated by the air spindle 5 based on the control of the control means 21. In this state, the probe 4 is moved in the Z-axis direction by the Z stage 9 in accordance with the shape change of the measurement surface of the DUT 2. At the same time, the probe 4 is moved in the X-axis direction by the X stage 7. At this time, the position of the probe 4 on the X axis and the position (x ₁ , z ₁ ) of the probe 4 on the Z axis are measured by the linear encoders 8 and 10. Further, the rotation angle (θ) of the air spindle 5 is measured by the rotary encoder 6. At the same time, the outputs (E ₁ , E ₂ , E ₃ ) of the _three position detectors (A1, A2, A3) are also measured. In this way, the shape measurement data (x ₁ , z ₁ , θ, E ₁ , E ₂ , E ₃ ) of the measurement surface of the DUT 2 is acquired as point sequence data and stored in the storage means. (Step S22).

Next, using the outputs (E ₁ , E ₂ , E ₃ ) of the _three position detectors of the shape measurement data acquired in step S22, the radial motion error e _x (θ of the air spindle 5 being measured is measured. ) Is calculated. The calculation method uses the multi-probe method used in roundness measurement, and the document (“Study on Accuracy Diagnosis Technology”, Transactions of the Japan Society of Mechanical Engineers (C), Vol. 48, No. 425 (Sho 57-1), p115-p123, Ko Mitsui No.) is referred to (step S23).
Further, the shape measurement data is corrected based on the obtained motion error e _x (θ) of the air spindle 5. Then, highly reliable shape measurement data (x ₂ , z ₂ , θ) from which the motion error e _x (θ) of the air spindle 5 has been removed is obtained (step S24). The method for correcting the shape measurement data is the same as that performed by using the correction formula (5) in the first embodiment, and the description thereof will be omitted.

  According to this embodiment, the detection axes of the three position detectors (A1, A2, A3) are positioned at different angular positions in the θ direction within the plane orthogonal to the rotation axis of the air spindle 5. It is installed to do. As a result, the radial movement error of the air spindle 5 that occurs during the shape measurement of the DUT 2 can be calculated by the multi-probe method. In the multi-probe method, it is possible to measure the radial movement error of the air spindle 5 in a state where the influence of the cylindrical surface over time is removed. Therefore, by removing the movement error of the air spindle 5 obtained by the multi-probe method from the shape measurement data of the object 2 to be measured, more reliable shape measurement data can be acquired.

  FIG. 12 is a modification of the second embodiment. In this modification, the motion error of the inclination (angular direction) of the air spindle 5 in the XZ direction is also calculated. Then, the motion error in the angular direction of the air spindle 5 is removed from the shape measurement data of the DUT 2 using the motion error calculation result. By doing in this way, more reliable shape measurement data can be acquired. FIG. 13 is a flowchart of shape measurement according to this modification. 14 and 15 are diagrams for explaining the shape measurement data correction method.

Hereinafter, the motion error calculation method, the shape measurement method, and the shape measurement data correction method in this modification will be described.
As shown in FIG. 12, the present modification uses three position detectors as in the second embodiment. However, it differs from the second embodiment in that each position detector is installed such that the height relative to the rotation axis of the air spindle 5 is different. With such a configuration, in the method for calculating the motion error of the air spindle 5 in step S23 of FIG. 11, not only the radial direction but also the angular direction motion error can be calculated. An angular direction motion error calculation method, shape measurement method, and shape measurement data correction method will be described with reference to FIGS.

  The processing unit of the three-dimensional shape measuring machine of this modification is almost the same as the processing unit of the first embodiment shown in FIG. The air spindle motion error calculating means 22 can calculate not only the radial motion error of the air spindle 5 but also the angular motion error. Since the configuration and operation of the other processing units are the same as those in the first embodiment, illustration and description are omitted.

First, the measurement method will be described with reference to FIG. Since step S31 is the same as step S1 of the first embodiment, description thereof is omitted. Step S32 is a process of measuring the shape of the DUT 2. In this step, the position (x ₁ , z ₁ ) of the probe 4 is measured by the linear encoders 8 and 10. Further, the rotation angle (θ) of the air spindle 5 is measured by the rotary encoder 6. At the same time, the outputs (E _A1 , E _A2 , E _A3 ) and (E _B1 , E _B2 , E _B3 ) of the six position detectors (A1, A2, A3) and (B1, B2, _B3 ) are measured. Here, the position z ₁ in the Z-axis direction of the probe 4 are based on the detection height position detector (A1, A2, A3).
In this way, the shape measurement data (x ₁ , z ₁ , θ, E _A1 , E _A2 , E _A3 , E _B1 , E _B2 , E _B3 ) of the measured surface of the DUT 2 is acquired as point sequence data. Then, it is stored in the storage means 23 (step S32).

Next, the radial motion error and the angular motion error of the air spindle are calculated. The calculation method is shown below.
First, using the output (E _A1 , E _A2 , E _A3 ) of the three position detectors (A1, A2, A3) of the shape measurement data acquired in step S32, the radial direction of the air spindle 5 being measured A motion error e _Ax (θ) is calculated. As a calculation method, a multi-probe method used in roundness measurement is used. For the calculation method, reference is made to the material ("Study on Accuracy Diagnosis Technology", Transactions of the Japan Society of Mechanical Engineers (C), Vol. 48, No. 425 (Akira 57-1, p115-p123) Furthermore, using the outputs (E _B1 , E _B2 , E _B3 ) of three position detectors (B1, B2, B3) installed at different heights, the radial movement of the air spindle 5 being measured The error e _Bx (θ) is calculated similarly.

The angular movement error e _a (θ) is calculated from the radial movement errors e _Ax (θ) and e _Bx (θ) of the air spindle 5 measured at different heights. A method of calculating the angular direction motion error e _a (θ) will be described with reference to FIG.
As shown in FIG. 14, the difference in installation height of the position detectors (A1, A2, A3) and (B1, B2, B3) is L _AB , and the difference in motion error in the radial direction is e _AB (θ). . When there is no motion error in the angular direction, e _AB (θ) = 0. If there is a motion error in the angular direction, the motion error e _a (θ) in the angular direction can be calculated by the following equation (step S33).
e _a (θ) = Sin – ¹ (e _AB (θ) / L _AB ) (10)
Further, the shape measurement data is corrected by the radial motion error e _Ax (θ) and the angular motion error e _a (θ) of the air spindle 5 obtained. That is, highly reliable shape measurement data (x ₂ , z ₂ , θ) is obtained by removing the motion error of the air spindle 5 (step S34).

Next, the procedure for removing the motion error of the air spindle 5 is shown below.
First, radial error correction is performed on the shape measurement data. The motion error correction in the radial direction can be expressed by the following equation.
x ₁ '= x ₁ −e _Ax (θ), z ₁ ' = z ₁ , θ = θ (11)

Next, the motion error correction in the angular direction is performed on the measurement data (x ₁ ′, z ₁ ′, θ) after the correction of the motion error in the radial direction calculated from the above equation (11). The correction method is performed with reference to FIG. Data (x ₂ , x ₂ , x ₁ , z ₁ ′, θ) after removing the motion error e _a (θ) in the angular direction of the air spindle 5 from the calculated measurement data (x ₁ ′, z ₁ ′, θ) after correcting the radial direction motion error. z ₂ , θ) is obtained by the following equation.

First, for explanation, it is assumed that the rotation axis of the air spindle 5 is t _Z (0). Also, let t _Z (e) be the rotation axis when the angular motion error e _a (θ) is included. Here, the origin 0 is the intersection of the height of the position detector (A1, A2, A3) and the rotation axis t _Z (0) of the air spindle 5. Further, the rotation axis t _Z (e) is inclined by an angular motion error e _a (θ) about the origin 0 as an axis. The direction perpendicular to the rotation axis t _Z (0) of the air spindle 5 from the origin 0 is defined as t _X (0), and the direction t orthogonal to the rotation axis when the angular motion error e _a (θ) is included. _{Let X} (e).

Next, when a perpendicular is drawn from the probe 4 to the rotation axis t _Z (e) of the air spindle 5, the point that intersects the rotation axis t _Z (0) is set to V. Also, let W be the intersection of the rotation axis t _Z (0) and z ₁ ′. Furthermore, if the distance between points W and V is Z ₁ , and the distance between V and origin 0 is Z ₂ ,
z ₂ = cos (e _a (θ)) × (Z ₂ )
Where z ₁ '= Z ₁ + Z ₂
z ₂ = cos (e _a (θ)) × (z ₁ '−Z ₁ )
From Z ₁ = x ₁ '× tan (e _a (θ))
z ₂ = z ₁ ′ × cos (e _a (θ)) − x ₁ ′ × tan (e _a (θ)) (12)

Further, when a perpendicular is drawn from the probe 4 in the direction t _X (e) perpendicular to the rotation axis t _Z (e) of the air spindle 5, the point of intersection is defined as W _X. Also, _let V _X be the intersection of perpendicular lines from V to t _X (e). Furthermore, if the distance between the intersection V _X and the origin 0 is X ₁ and the distance between the intersection V _X and W _X is X ₂ ,
x ₂ = X ₁ + X ₂
Where X ₂ = x ₁ '/ cos (e _a (θ))
Also, X ₁ = Z ₂ × sin (e _a (θ))
Z ₂ = z ₁ '−Z ₁
X ₁ = (z ₁ '−Z ₁ ) × sin (e _a (θ))
Furthermore, Z ₁ = x ₁ '× tan (e _a (θ))
Therefore, X ₁ = z ₁ ′ × sin (e _a (θ)) − x ₁ ′ × sin ² (e _a (θ)) / cos (e _a (θ))
From the above, x ₂ = [z ₁ ′ × sin (e _a (θ)) − x ₁ ′ × sin ² (e _a (θ)) / cos (e _a (θ))]
+ [X ₁ '/ cos (e _a (θ))] (13)
From the above equations (12) and (13), the shape measurement data (x ₂ , z ₂ , θ) can be calculated.

  As is clear from the above description, according to this modification, the same operation and effect as the second embodiment can be obtained, and not only the radial motion error of the air spindle 5 but also the angular motion error. Can also be removed from the shape measurement data of the DUT 2. Therefore, more reliable shape measurement data can be acquired.

Third Embodiment FIG. 16 is a perspective view schematically showing a main part of an apparatus for carrying out a three-dimensional shape measuring method according to a third embodiment. FIG. 17 is a flowchart showing the measurement procedure of the third embodiment.
Hereinafter, the third embodiment will be described with reference to FIGS. 16 and 17. FIG. Also in this embodiment, the vertical direction is the Z-axis direction and the horizontal direction is the X-axis direction, as in the first embodiment. In this coordinate system, the air spindle 5 is installed on the surface plate 11 with the Z-axis direction as the rotation axis. The object to be measured 2 is disposed on a jig 3 installed on the air spindle 5. Further, the four position detectors (C1, C2, C3, C4) are installed in directions where each detection axis is parallel to the rotation axis, concentric with the rotation axis, and at different angular positions in the θ direction. Yes. Here, one of the position detectors can measure an angle such as an angle sensor.

The three-dimensional shape measuring apparatus 14 of this embodiment is different from the first embodiment and the second embodiment in that four position detectors (C1, C2, C3, C4) are installed. The four position detectors (C1, C2, C3, C4) calculate the motion error in the axial direction (Z-axis direction) of the air spindle 5 during the shape measurement of the surface to be measured of the device under test 2. Then, using the calculation result of the motion error, the motion error in the axial direction of the air spindle 5 is removed from the shape measurement data of the object to be measured 2 so that more reliable measurement data can be acquired.
Since other configurations are the same as those of the first and second embodiments, illustration and description thereof are omitted. Further, the processing unit of the present embodiment is almost the same as the processing unit of the first embodiment shown in FIG. However, the air spindle motion error calculating means 22 is different from the processing unit of the first embodiment in that the motion error in the axial direction of the air spindle 5 can be calculated.

Next, a specific measurement method will be described with reference to FIG.
First, step S41 is the same as step S1 in the first embodiment, and a description thereof will be omitted. Step S42 is a process for measuring the shape of the DUT 2. In this shape measuring step, the device under test 2 is rotated by the air spindle 5 based on the control of the control means 21. In this state, the probe 4 is moved in the Z-axis direction by the Z stage 9 in accordance with the shape change of the measurement surface of the DUT 2. At the same time, the probe 4 is moved in the X-axis direction by the X stage 7. At this time, the position of the probe 4 on the X axis and the position (x ₁ , z ₁ ) of the probe 4 on the Z axis are measured by the linear encoders 8 and 10. Further, the rotation angle (θ) of the air spindle 5 is measured by the rotary encoder 6. At the same time, the outputs (E _C1 , E _C2 , E _C3 , E _C4 ) of the four position detectors (C1, C2, C3, _C4 ) are also measured. In this way, the shape measurement data (x ₁ , z ₁ , θ, E _C1 , E _C2 , E _C3 , E _C4 ) of the DUT 2 is acquired as point sequence data and stored in the storage means 23. (Step S42).

Next, using the four position detector outputs (E _C1 , E _C2 , E _C3 , E _C4 ) of the shape measurement data acquired in step S42, the motion error e _Z of the air spindle 5 being measured is measured in the axial direction. (Θ) is calculated. As a calculation method, a mixing method that is a method of calculating a motion error in the axial direction of a lathe spindle used for ultra-precision machining is used. For the calculation method, refer to the document ("Research on precision measurement of axial and angular motion errors of machine tool rotation spindles by the multipoint method" Journal of Precision Engineering Vol. 67, No. 7, 2001, p1120 to p1124 Ichiro Ogura, Yuichi Okazaki) (Step S43).

Further, the shape measurement data (x ₂ , z ₂ , θ) is obtained by correcting the shape measurement data based on the obtained motion error e _Z (θ) of the air spindle 5 and removing the motion error of the air spindle 5. Is obtained (step S44).
The correction formula for the shape measurement data is shown below.
x ₂ = x ₁ , z ₂ = z ₁ −e _Z (θ), θ = θ (14)

  According to the present embodiment, the detection axes of the four position detectors (C1, C2, C3, C4) are parallel to the rotation axis of the air spindle 5, and are further concentric with each other on the concentric circle with respect to the rotation axis. By installing at different angles in the direction, it is possible to calculate the axial movement error of the air spindle 3 that occurs during the shape measurement of the object 2 to be measured by the mixing method. In the mixing method, the movement error in the axial direction of the air spindle 5 can be measured without being affected by changes in the cylindrical surface over time, shape errors, etc., so the axial movement error of the air spindle 5 obtained by the mixing method is Therefore, more reliable shape measurement data can be obtained.

It is a perspective view which shows roughly the principal part of the measuring apparatus for demonstrating 1st Example of the three-dimensional shape measuring method by this invention. It is a block diagram of the process part for implementing the measuring method of 1st Example. It is a flowchart for demonstrating the measuring method of 1st Example. (a) And (b) is a figure for demonstrating the calculation method of the roundness shape error by the inversion method. (a), (b), (c) is a figure for demonstrating the calculation method of the roundness shape error by a phase difference method. It is a perspective view similar to FIG. 1 which shows the modification of 1st Example. (a) And (b) is a figure for demonstrating the calculation method of the roundness shape error by the improved inversion method. It is a flowchart for demonstrating the shape measuring method using the improved inversion method. It is a perspective view similar to FIG. 1 which shows the other modification of 1st Example. It is a perspective view which shows roughly the principal part of the measuring apparatus for demonstrating 2nd Example of the three-dimensional shape measuring method by this invention. It is a flowchart for demonstrating the measuring method of 2nd Example. It is a principal part perspective view which shows the modification of 2nd Example. It is a flowchart for demonstrating the shape measuring method using the modification of FIG. It is a figure for demonstrating the correction method of shape measurement data. It is a figure for demonstrating the correction method of shape measurement data. It is a perspective view which shows roughly the principal part of the measuring apparatus for demonstrating 3rd Example of the three-dimensional shape measuring method by this invention. It is a flowchart for demonstrating the measuring method of 3rd Example. It is a perspective view which shows roughly the principal part of one example of the conventional three-dimensional shape measuring apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Position detector 2 Measured object 3 Jig 4 Probe 5 Air spindle 6 Rotary encoder 7 X stage 8, 10 Linear scale 9 Z stage 11 Surface plates 12, 12 ', 12 ", 13, 14 Three-dimensional shape measuring device 21 Control means 22 Air spindle motion error calculation means 23 Storage means 24 Coordinate conversion means A, A ′, A1 to A3, B1 to B3, C1 to C4 Position detectors P and P ′ Position markers

Claims (13)

A shape measuring step for measuring from the rotation axis direction while rotating the object to be measured, a correction value measuring step for measuring from a direction orthogonal to the rotation axis direction, a measurement result of the shape measuring step, and the correction value measuring step A three-dimensional shape measuring method comprising a calculation step of obtaining a three-dimensional shape of the object to be measured from the measurement result of
In the correction value measurement step, measurement is performed at a first sub-step in which measurement is performed with the positional relationship between the holding member and the rotation mechanism as a first relative position, and at a second relative position that is different from the first positional relationship. A three-dimensional shape measuring method comprising at least a second sub-step to be performed.   The measurement in the correction value measuring step is performed at a predetermined position along the rotation axis, and the position of the holding member in the second positional relationship is determined from the position of the holding member in the first positional relationship. The position at which the holding member is rotated 180 degrees around the rotation axis, and the measurement in the first sub-step and the measurement in the second sub-step are performed with a time difference. 3. The three-dimensional shape measuring method according to 1.   The measurement in the correction value measurement step is performed at two positions including another position, and the other position is a position separated from the predetermined position by a predetermined distance along the rotation axis direction. The three-dimensional shape measuring method according to claim 2, wherein:   A third sub-step for performing measurement in a third positional relationship different from the first positional relationship and the second positional relationship, wherein the measurement in the correction value measuring step is performed at a predetermined position along the rotation axis; And the position of the holding member in the second positional relationship is a position obtained by rotating the holding member around the rotation axis by Φ degrees from the position of the holding member in the first positional relationship. The position of the holding member in the positional relationship of 3 is a position obtained by rotating the holding member around the rotation axis by 2Φ degrees from the position of the holding member in the first positional relationship, and in the first sub-step The three-dimensional shape measuring method according to claim 1, wherein the measurement, the measurement in the second sub-step, and the measurement in the third sub-step are performed with a time difference. A shape measuring step for measuring from the rotation axis direction while rotating the object to be measured, a correction value measuring step for measuring from a direction orthogonal to the rotation axis direction, a measurement result of the shape measuring step, and the correction value measuring step A three-dimensional shape measuring method comprising a calculation step of obtaining a three-dimensional shape of the object to be measured from the measurement result of
The correction value measuring step includes a first sub-step of measuring from a first direction;
At least a second sub-step for measuring from a second direction different from the first direction;
The measurement in the correction value measurement step is performed at a predetermined position along the rotation axis,
The three-dimensional shape measuring method, wherein the measurement in the first sub-step and the measurement in the second sub-step are performed simultaneously.   6. The three-dimensional shape measuring method according to claim 5, wherein the first direction and the second direction are parallel to each other and both intersect the rotation axis. The correction value measuring step includes a third sub-step of measuring from a third direction different from the first direction and the second direction;
The first direction, the second direction, and the third direction all intersect the rotation axis,
6. The three-dimensional shape measurement method according to claim 5, wherein the measurement in the first sub-step, the measurement in the second sub-step, and the measurement in the third sub-step are performed simultaneously. The correction value measuring step includes at least a fourth sub-step of performing measurement at different positions along the rotation axis,
The three-dimensional shape measuring method according to claim 7, wherein the fourth sub-step performs the first sub-step, the second sub-step, and the third sub-3 step simultaneously. A shape measuring step for measuring from the rotation axis direction while rotating the object to be measured, a correction value measuring step for measuring from the same direction as the shape measuring step, a measurement result of the shape measuring step, and a correction value measuring step. In a three-dimensional shape measurement method comprising a calculation step of obtaining a three-dimensional shape of the object to be measured from a measurement result,
The correction value measurement step measures a peripheral portion of the measurement region performed in the shape measurement step,
3. The three-dimensional shape measurement method, wherein the measurement in the shape measurement step and the measurement in the correction value measurement step are performed simultaneously.   The three-dimensional shape measuring method according to claim 9, wherein the correction value measuring step measures four positions in the peripheral portion.   9. The three-dimensional shape measurement method according to claim 1, wherein a roundness shape error and a radial direction motion error are calculated in the correction value measurement step.   6. The three-dimensional shape measuring method according to claim 2, wherein the measurement at the predetermined position is a position at which the holding member is measured. 6. The three-dimensional shape measuring method according to claim 3, wherein the measurement at the different position is a position at which the rotation mechanism is measured.