JP4646520B2 - Three-dimensional shape measuring method and apparatus - Google Patents

Description

  The present invention relates to a three-dimensional shape measuring method for measuring the shape of an object to be measured such as an optical component or a mold with high accuracy.

  As a three-dimensional shape measurement method for measuring the shape of an object such as an optical component or a mold with high accuracy, generally, a non-contact or contact type probe is scanned along the shape of the object to be measured. A method for measuring the shape of an object is known. As an example of the probe scanning method, there is a method of scanning the probe in the X direction while rotating the object to be measured in the θ direction (hereinafter referred to as “Rθ scanning method”).

  This Rθ scanning type three-dimensional shape measuring method is disclosed in Patent Document 1, for example. That is, as shown in FIG. 9, a three-dimensional shape measuring machine 101 to which this Rθ scanning type three-dimensional shape measuring method is applied includes an optical probe 102, a Z stage 103, an X stage 104, a θ stage 105, A Z laser length measuring device 106, a Z reference mirror 107, an X laser length measuring device 108, an X reference mirror 109, and a θ rotary encoder 110 are included.

  Here, the DUT 111 is an aspheric lens. Such an object 111 to be measured is arranged on the θ stage 105 so that the optical axis of the object 111 to be measured and the rotation axis of the θ stage 105 are substantially matched.

  The optical probe 102 is scanned in a non-contact manner along the object to be measured 111. That is, the Z stage 103 moves the optical probe 102 in the Z-axis direction. The X stage 104 moves the optical probe 102 and the Z stage 103 in the X-axis direction. On the other hand, the θ stage 105 rotates the DUT 111 in the θ direction.

  The Z laser length measuring device 106 measures the position of the optical probe 102 in the Z-axis direction with respect to the Z reference mirror 107. The X laser length measuring device 108 measures the position of the optical probe 102 in the X-axis direction with respect to the X reference mirror 109. The θ rotary encoder 110 measures the rotation angle of the θ stage 105. Then, a personal computer (not shown) takes in the measured values of the Z laser length measuring device 106, the X laser length measuring device 108, and the θ rotary encoder 110 as measurement data.

  Next, the operation of the three-dimensional shape measuring machine 101 having such a configuration will be described.

  That is, the X stage 104 is moved by a predetermined amount to be stopped, the object to be measured 111 is rotated in the θ direction at a constant speed by the θ stage 105, and the personal computer (not shown) starts to take in the measurement data. Then, a personal computer (not shown) captures measurement data at a constant sampling time, and when the object to be measured 111 makes one rotation in the θ direction, the capture of measurement data is stopped. Thereafter, the X stage 104 is moved again by the predetermined amount. Such an operation is repeated to measure the three-dimensional shape of the surface of the DUT 111.

  Then, concentric measurement data as shown in FIG. 10 is acquired. However, this figure has shown a mode that the acquired measurement data was seen from the Z-axis direction. In the same figure, the point indicates the position where the measurement data is taken in, and the two-dot chain line indicates the locus of the probe 102 scanning the surface of the measurement object 111 (the same applies to the subsequent measurement data diagrams).

  Further, another method of obtaining measurement data by the three-dimensional shape measuring machine 101 having the above configuration will be described.

  That is, the object to be measured 111 is rotated in the θ direction at a constant speed by the θ stage 105. Then, while moving the X stage 104, the personal computer captures the measurement data at a constant sampling time.

  When such an acquisition method is performed, spiral measurement data as shown in FIG. 11 is acquired.

In this way, the three-dimensional shape of the DUT 111 can be measured.
JP 2000-266524 A

  By the way, the linear velocity of the optical probe 102 (speed at which the optical probe 102 moves relative to the object to be measured 111) is slow at the center of the object to be measured 111 (portion close to the optical axis of the object to be measured 111). , It becomes faster at the peripheral part (the part close to the outer periphery of the DUT 111). For this reason, when the linear velocity of the optical probe 102 increases in the peripheral portion, the optical probe 102 cannot follow the minute irregularities of the surface shape of the object 111 to be measured, and a measurement error may occur.

  In order to avoid this, the rotational speed of the θ stage 105 may be lowered. If the number of rotations is lowered, the linear velocity of the optical probe 102 is also reduced in the peripheral portion, and measurement errors are less likely to occur.

  However, when acquiring concentric measurement data, if the number of rotations of the θ stage 105 is lowered in this way, the measurement time becomes longer by that amount.

  Further, when acquiring spiral measurement data, as shown in FIG. 12, the interval Px of the measurement data in the radial direction of the DUT 111 becomes longer (FIG. 12 shows the measurement data acquisition of FIG. 11). The measurement data when the rotation speed of the θ stage 105 is lowered than the time is shown). Here, generally, when the interval of measurement data becomes too large, the shape of the surface cannot be expressed accurately, and the measurement accuracy is lowered. Therefore, by reducing the rotation speed of the θ stage, the measurement accuracy in the circumferential direction is increased, but the measurement accuracy in the radial direction is lowered, and the measurement accuracy may be substantially lowered.

  In addition, the measurement time of the lens surface shape by the three-dimensional shape measuring machine is extremely long compared to the measurement time of the interferometer that can measure the shape of the entire lens surface at once. Therefore, the three-dimensional shape measuring machine is strongly required to shorten the measurement time.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a three-dimensional shape measurement method and apparatus that reduce measurement errors and have a short measurement time.

According to one aspect of the three-dimensional shape measuring method of the present invention, the measurement object is rotated in the θ direction by a rotation mechanism, the rotation angle θ is measured, and the shape of the measurement object rotated by the rotation mechanism is measured. The step of moving the moving probe in the X direction substantially orthogonal to the rotation axis of the rotation mechanism and measuring the position coordinates of the probe, and the distance in the X direction between the rotation axis of the rotation mechanism and the probe are longer, the lower the rotational speed of the rotary mechanism, by slowing the movement speed in the X direction of the probe, a step of changing the moving speed of the X-direction of the rotational speed and the probe of the rotating mechanism, the probe Obtaining measurement data of the object to be measured obtained from the position coordinates, and an instruction signal for changing at least one of the rotational speed of the rotating mechanism and the moving speed of the probe in the X direction; Deleting the measured data of the object under measurement before and after the timing at which at least one of the rotational speed and the moving speed is changed based on the obtained instruction signal, .

One aspect of the three-dimensional shape measuring apparatus of the present invention includes a probe which moves along the shape of the workpiece, said a rotating mechanism you want to rotate. The object to be measured in the θ direction, the rotation angle θ of the object to be measured a rotation angle measuring means for measuring, the probe was moved to the rotation axis and the X direction substantially perpendicular of the rotary mechanism, and the probe position coordinate measuring means for measuring the position coordinates of the probe, and the rotation shaft of the rotation mechanism The longer the distance in the X direction from the probe, the lower the rotational speed of the rotating mechanism and the slower the moving speed of the probe in the X direction, so that the rotational speed of the rotating mechanism and the X direction of the probe can be reduced. Changing means for changing the moving speed of the probe, measurement data of the object to be measured obtained from the position coordinates of the probe, an instruction signal for changing the rotational speed of the rotating mechanism and the moving speed of the probe in the X direction, , And based on the instruction signal, the computer deletes the measurement data of the measurement object before and after the timing of changing the rotation speed and the moving speed within a specified range. .

  According to the present invention, it is possible to provide a three-dimensional shape measurement method and apparatus that reduce measurement errors and have as short a measurement time as possible.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[First Embodiment]
First, a first embodiment of the present invention will be described.

[Constitution]
FIG. 1A is a diagram showing a configuration of a three-dimensional shape measuring machine 1 to which a three-dimensional shape measuring method according to the first embodiment of the present invention is applied.

  The three-dimensional shape measuring machine 1 includes a probe 2, a tip sphere 3, a static pressure air bearing 4, a leaf spring 5, a leaf spring holding portion 6, a micro linear scale 7, a Z stage 8, and an X stage. 9, Z laser length measuring device 10, X laser length measuring device 11, Z reference mirror 12, X reference mirror 13, θ stage 14, θ rotary encoder 15, measuring machine frame 16, stage The controller 17, the personal computer 18, and three right-angle reflecting prisms 19, 20, and 21 are included.

  Here, the probe 2 is scanned along the shape of the DUT 22. The tip sphere 3 is formed integrally with the probe 2 and contacts the surface of the object to be measured 22 when the probe 2 is scanned. The hydrostatic air bearing 4 holds the probe 2 so as to be movable in the Z-axis direction. The leaf spring 5 elastically supports the probe 2 in the Z-axis direction. The leaf spring holding portion 6 fixes the leaf spring 5 to the static pressure air bearing 4. The Z stage 8 drives the static pressure air bearing 4 in the Z-axis direction. The X stage 9 drives the Z stage 8 in the X axis direction substantially orthogonal to the Z axis. The micro linear scale 7 includes a scale unit 7 a fixed to the probe 2 and a reading unit 7 b fixed to the Z stage 8. The micro linear scale 7 measures the displacement of the probe 2 in the Z-axis direction with respect to the hydrostatic air bearing 4. The Z reference mirror 12 and the X reference mirror 13 are fixed to the frame 16. The Z laser length measuring device 10 includes a length measuring portion 10 a fixed to the frame 16 and a prism portion 10 b fixed to the probe 2. The Z laser length measuring device 10 measures the position of the probe 2 in the Z-axis direction. Here, right-angle reflecting prisms 19 and 20 are arranged between the length measuring unit 10a and the prism unit 10b. In this way, even when the probe 2 is displaced in the Z-axis direction, an optical path for length measurement is always formed between the length measurement unit 10a and the prism unit 10b. The X laser length measuring device 11 includes a length measuring portion 11 a fixed to the frame 16 and a prism portion 11 b fixed to the Z stage 8. The X laser length measuring device 11 measures the position of the probe 2 in the X-axis direction. Here, a right-angle reflecting prism 21 is disposed between the length measuring unit 11a and the prism unit 11b. By doing in this way, even if the probe 2 is displaced in the X-axis direction, an optical path for length measurement is always formed between the length measuring portion 11a and the prism portion 11b.

  Each of the Z laser length measuring device 10 and the X laser length measuring device 11 is a laser length measuring device having a single-pass interferometer configuration as shown in FIG. 2, for example.

  That is, the laser length measuring device 50 measures the amount of movement of the flat mirror 51 on the length measuring axis 50c. The laser length measuring device 50 includes a length measuring portion 50a and a prism portion 50b.

  The length measuring unit 50 a includes a laser light source 52, a receiver 53, and a polarizing plate 54. Here, the laser light source 52 emits a light beam composed of P-polarized light and S-polarized light whose polarization directions are orthogonal to each other. The receiver 53 receives the returning light flux from the plane mirror 51 and the prism unit 50b. The polarizing plate 54 transmits only linearly polarized light in one direction.

  The prism unit 50 b includes a polarization beam splitter 55 that transmits P-polarized light and reflects S-polarized light, λ / 4 plates 56 and 57, a plane mirror 58, and a right-angle reflecting prism 59.

  In such a configuration, the P-polarized light is transmitted through the polarization beam splitter 55 and the S-polarized light is reflected from the light beam from the laser light source 52. The light beam reflected by the polarization beam splitter 55 becomes a measurement light beam, and the transmitted light beam becomes a reference light beam.

  The measurement light beam reflected by the polarization beam splitter 55 passes through the λ / 4 plate 56 and becomes circularly polarized light, and is reflected by the plane mirror 51. The circularly polarized light reflected by the plane mirror 51 passes through the λ / 4 plate 56 again to become P-polarized light, and this time passes through the polarizing beam splitter 55.

  On the other hand, the reference light beam that has passed through the polarization beam splitter 55 passes through the λ / 4 plate 57 and becomes circularly polarized light, and is reflected by the plane mirror 58. The circularly polarized light reflected by the plane mirror 58 is transmitted again through the λ / 4 plate 57 to become S-polarized light, and is then reflected by the polarizing beam splitter 55 and overlaps with the measurement light beam transmitted through the polarizing beam splitter 55.

  The overlapping measurement light beam and reference light beam are reflected by the right-angle reflecting prism 59, and only the linearly polarized light component in one direction is transmitted through the polarizing plate 54, causing interference. The interference measurement beam and reference beam are received by the receiver 53. In the receiver 53, the variation in the phase difference between the measurement light beam and the reference light beam is detected by the interference signal. The interference signal received by the receiver 53 is input to a calculation unit (not shown), converted into a length measurement value, and outputs a length measurement value.

  Here, the optical path length of the reference light beam is always constant. On the other hand, the optical path length of the measurement light beam changes as the plane mirror 51 is displaced. Therefore, the laser length measuring device 50 measures the amount of movement of the plane mirror 51 on the length measuring axis 50c.

  The Z laser length measuring device 10 and the X laser length measuring device 11 are not limited to the configuration of the single path interferometer shown in FIG. It is sufficient if the amount of movement with respect to the reference mirrors 12 and 13 can be measured. For example, a double pass interferometer may be used.

  Further, the Z stage 8 and the X stage 9 are composed of, for example, a guide composed of a static pressure air bearing or a linear guide, and a driving means composed of a combination of a ball screw and a stepping motor or a linear motor.

  The θ stage 14 includes, for example, a static pressure air bearing and a motor.

  In addition, the DUT 22 is an aspheric lens. However, the DUT 22 is not limited to an aspheric lens. For example, if the object to be measured 22 has a rotational axis symmetric shape such as a spherical lens or a lens mold, the same effect is produced, and three-dimensional shape measurement is possible even with a free-form surface or its mold.

[Action]
Next, the operation of the three-dimensional shape measuring machine 1 will be described.

  First, the device under test 22 is fixed to the θ stage 14 so that the optical axis of the device under test 22 and the rotation axis of the θ stage 14 are substantially aligned. Next, the X stage 9 is driven to make the central axis of the probe 2 substantially coincide with the rotation axis of the θ stage 14. Then, the Z stage 8 is driven to bring the tip sphere 3 into contact with the object 22 to be measured. These setting operations may be performed by the stage control unit 17 or may be performed manually by an operator.

  Here, when the stage control unit 17 rotates the θ stage 14, the DUT 22 rotates. When the stage control unit 17 further drives the X stage 9 by a predetermined amount, the Z stage 8, the static pressure air bearing 4 and the probe 2 are integrally moved in the X-axis direction. At this time, the shape (the height in the Z-axis direction) of the measurement object 22 at the position of the probe 2 changes due to the rotation of the measurement object 22 or the movement of the probe 2 in the X-axis direction. Then, the leaf spring 5 bends according to the shape of the object 22 to be measured, and the probe 2 moves in the Z-axis direction with respect to the static pressure air bearing 4. At the same time, the scale unit 7a of the micro linear scale 7 is displaced with respect to the reading unit 7b, and the reading unit 7b measures the displacement. Thus, the stage controller 17 always keeps the position of the probe 2 relative to the static pressure air bearing 4 constant according to the length measurement value of the micro linear scale 7 (that is, the deflection of the leaf spring 5 is constant). Then, the Z stage 8 is driven. In this way, the probe 2 is scanned along the shape of the DUT 22.

  At this time, the light beam emitted from the length measuring unit 10 a of the Z laser length measuring device 10 is reflected by the right-angle reflecting prism 19 fixed to the X stage 9 and further reflected by the right-angle reflecting prism 20 fixed to the probe 2. Then, the light enters the prism portion 10b. The light beam incident on the prism portion 10b is divided into the reference light beam and the measurement light beam as described above inside the prism portion 10b. The measurement light beam emitted from the prism unit 10b is reflected by the Z reference mirror 12 and enters the prism unit 10b again. Then, the reference light beam and the measurement light beam are superposed inside the prism unit 10b and emitted from the prism unit 10b. The light beam emitted from the prism portion 10b is reflected by the right-angle reflecting prism 20, and further reflected by the right-angle reflecting prism 19, and enters the length measuring portion 10a.

  The optical path length between the length measuring unit 10 a and the right-angle reflecting prism 19 changes as the X stage 9 moves. However, since this is a common optical path for the measurement light beam and the reference light beam, this change in optical path length is not detected by the Z laser length measuring device 10. Further, the optical path length between the right-angle reflecting prism 19 and the right-angle reflecting prism 20 changes with the movement of the Z stage 8 and the displacement of the probe 2 with respect to the static pressure air bearing 4. However, since this is a common optical path for the measurement light beam and the reference light beam, this change in optical path length is not detected by the Z laser length measuring device 10. Furthermore, the optical path length between the right-angle reflecting prism 20 and the prism portion 10b is always constant. On the other hand, between the prism part 10b and the Z reference | standard mirror 12, it is an optical path only for a measurement light beam. This optical path length changes with the movement of the Z stage 8 and the displacement of the probe 2 with respect to the hydrostatic air bearing 4. This change in optical path length is detected by the Z laser length measuring instrument 10. As described above, the Z laser length measuring device 10 measures the amount of movement of the probe 2 in the Z-axis direction with respect to the reference mirror 12.

  On the other hand, the light beam emitted from the length measuring portion 11a of the X laser length measuring device 11 is reflected by the right-angle reflecting prism 21 fixed to the X stage 9, and enters the prism portion 11b. The light beam incident on the prism portion 11b is divided into a reference light beam and a measurement light beam inside the prism portion 11b. The measurement light beam emitted from the prism portion 11b is reflected by the X reference mirror 13 and enters the prism portion 11b again. Then, the reference light beam and the measurement light beam are superposed inside the prism portion 11b and emitted from the prism portion 11b. The light beam emitted from the prism portion 11b is reflected by the right-angle reflecting prism 21 and enters the length measuring portion 11a.

  The optical path length between the length measuring unit 11a and the right-angle reflecting prism 21 changes as the X stage 9 moves. However, since this is a common optical path for the measurement light beam and the reference light beam, this change in the optical path length is not detected by the X laser length measuring device 11. Further, the optical path length between the right-angle reflecting prism 21 and the prism portion 11 b changes as the Z stage 8 moves. However, since this is a common optical path for the measurement light beam and the reference light beam, this change in the optical path length is not detected by the X laser length measuring device 11. On the other hand, between the prism portion 11b and the X reference mirror 13, there is an optical path for only the measurement light beam. This optical path length changes as the X stage 9 moves, and the change in the optical path length is detected by the X laser length measuring instrument 11. Thus, the X laser length measuring device 11 measures the amount of movement of the probe 2 in the X-axis direction relative to the X reference mirror 13.

  Further, the θ rotary encoder 15 measures the rotation angle of the DUT 22.

  Then, the personal computer 18 takes in the measured values of the Z laser length measuring device 10, the X laser length measuring device 11, and the θ rotary encoder 15 as measurement data at a constant sampling time.

Here, the distance in the X-axis direction between the probe 2 and the rotation axis of the θ stage 14, which is measurement data based on the measurement value of the X laser length measuring instrument 11, is L [mm], and the measurement value of the θ rotary encoder 15. When the rotation speed of the θ stage 14 which is the measurement data based on it is R [round / sec], the linear velocity Vm is
Vm = 2L × π × R [mm / sec] (1)
It becomes. In the present embodiment, the stage controller 17 is configured such that when the linear velocity target value is Sm and the linear velocity allowable range is Dm,
Sm−Dm <Vm <Sm + Dm (2)
The rotational speed R of the θ stage 14 is changed so as to satisfy the above condition.

  That is, the stage control unit 17 rotates the θ stage 14 while scanning the probe 2 along the shape of the object 22 to be measured. Next, the stage control unit 17 drives the X stage 9 to move the probe 2 and stops the X stage 9. Then, when the personal computer 18 starts capturing measurement data and the θ stage 14 makes one rotation, the capturing of measurement data is stopped. The stage controller 17 again drives the X stage 9 to move the probe 2 and stops the X stage 9. This operation is repeated.

  Before moving the probe 2, the stage controller 17 calculates the linear velocity Vm after movement from the position after the probe 2 has moved and the rotation speed of the θ stage 14 by the above equation (1). When the calculated linear velocity Vm after movement is faster than a prescribed value (that is, Vm> Sm + Dm), the rotation speed of the θ stage 14 becomes Vm> Sm−Dm. Change to the minimum number of revolutions R and slow down the rotational speed.

  By repeating this control, concentric measurement data as shown in FIG. 1B is obtained.

  Note that the target value Sm and the allowable range Dm of the linear velocity Vm are determined by the following method, for example.

  First, the object to be measured 22 is scanned at a sufficiently low linear velocity to measure a three-dimensional shape. Next, a target value Sm and an allowable range Dm of an appropriately high linear velocity are set, and a three-dimensional shape is measured. If there is no difference between the two measured values thus obtained, the target value Sm and the allowable range Dm of a higher linear velocity are set, and the three-dimensional shape is measured again. Conversely, if there is a difference between the two measurement values, a measurement error has occurred, so the target value Sm of the slower linear velocity and the allowable range Dm are set, and the three-dimensional shape is measured again. By this method, it is possible to determine the optimum linear velocity target value Sm and allowable range Dm for the DUT 22.

  The optimum linear velocity is mainly determined by the tracking performance of the probe 2. As the follow-up performance of the probe 2, the approximate follow-up performance of the probe 2, that is, the target value and allowable range of the linear velocity at which no measurement error occurs are determined by the above experimental method determined by the configuration of the measuring machine and the control method. Can be sought. Therefore, during normal measurement, measurement may be performed using values obtained in advance.

  However, strictly speaking, the optimum linear velocity is also affected by the shape and surface roughness of the object to be measured. On the other hand, for example, there are cases where it is desired to determine more optimal measurement conditions for reasons such as measuring a large amount of objects having the same specifications (shape, manufacturing method, etc.). Therefore, in such a case, by measuring the object to be measured with the above-described experimental method, the target value and the allowable range of the linear velocity for the object to be measured with the specification are obtained. The optimum measurement can be performed for the object to be measured.

  Further, the specifications of the measured object measured in the past, and the target value and allowable range of the linear velocity with respect to the specifications of the measured object may be stored in a database. In that case, when measuring a device with a new specification, the target value and allowable range of the linear velocity of the same manufacturing method and similar shape are automatically selected from the past device database. It may be.

  In this way, the three-dimensional shape of the DUT 22 can be measured.

[effect]
In order to explain the effect of this embodiment, FIG. 3 and FIG. 4 show measurement data when the control of the θ stage 14 is different from FIG. In addition, Pm in each figure is the space | interval of the measurement data of the to-be-measured object 22 in the circumferential direction. Since the sampling time of measurement data is constant, Pm corresponds to the magnitude of the linear velocity.

  FIG. 3 is the same as the rotation speed of the θ stage 14 when measuring the central portion of the DUT 22 in FIG. 1B which is measurement data of the present embodiment, and the rotation speed of the θ stage 14. Shows the measurement data when is always constant.

  4 is the same as the rotation speed of the θ stage 14 when measuring the peripheral portion of the object 22 to be measured in FIG. The measurement data when the rotation speed is always constant is shown.

  The central portion of the device under test 22 indicates a portion near the optical axis of the device under test 22, and the peripheral portion indicates a portion near the outer periphery of the device under test 22.

  First, the measurement data of this embodiment shown in FIG. 1B is compared with the measurement data of FIG. In the case of FIG. 3, the linear velocity is equal (Pm3a = Pm1a) in the central portion as compared with the present embodiment, so that the measurement accuracy is also equal. On the other hand, in the peripheral part, the linear velocity is faster than that of the present embodiment (Pm3b> Pm1b). Here, in the case of FIG. 3, since the linear velocity in the peripheral portion is too high, the probe 2 cannot follow the surface shape of the object to be measured 22, and the measurement accuracy is lowered. Therefore, in the case of FIG. 3, the measurement time is shorter as the number of rotations of the θ stage 14 is higher than in the present embodiment, but the measurement accuracy of the peripheral portion is lowered. Therefore, compared with the case of FIG. 3, this embodiment can reduce a decrease in measurement accuracy at the peripheral portion, and can realize highly accurate three-dimensional shape measurement.

  Here, in FIG. 3, in order to avoid the problem that the probe 2 cannot follow in the peripheral portion, the rotational speed of the θ stage 14 may be lowered. FIG. 4 shows measurement data when the rotational speed of the θ stage 14 is lowered.

  Next, the measurement data of this embodiment shown in FIG. 1B is compared with the measurement data of FIG. In the case of FIG. 4, since the linear velocity is equivalent (Pm4b = Pm1b) in the peripheral portion, the measurement accuracy is also equivalent to this embodiment. On the other hand, in the central portion, the linear velocity is slower than that of the present embodiment (Pm4a <Pm1a). However, the linear velocity (Pm1a) at the center of the present embodiment is within the above-described allowable range. Therefore, since the linear velocity at the central portion of the present embodiment is sufficiently slow, there is no problem that the probe 2 cannot follow and the measurement accuracy is lowered. Therefore, the measurement accuracy is substantially the same at the center. Further, in the case of FIG. 4, the measurement time becomes longer as the number of rotations of the θ stage 14 is lower than in the present embodiment. Therefore, this embodiment can realize three-dimensional shape measurement that shortens the measurement time while maintaining the same measurement accuracy as compared with the case of FIG.

  As described above, in the present embodiment, by controlling the linear velocity to be within a certain range, the probe 2 is close to the limit at which the probe 2 can follow the device under test 22 at both the center and the periphery of the device under test 22. It is possible to scan at a linear velocity.

  Therefore, according to this embodiment, it is possible to realize measurement of a three-dimensional shape that reduces the measurement error in the peripheral portion and shortens the measurement time as much as possible.

[Modification]
Of course, each configuration of the first embodiment can be variously modified and changed.

  For example, in the present embodiment, the measurement is performed after the probe 2 and the optical axis of the object to be measured 22 are substantially coincident with each other, but it is sufficient that measurement data of the entire object to be measured 22 can be acquired. Measurement may be started from the part, or measurement may be performed from any part of the DUT 22.

  In the present embodiment, the stage control unit 17 shows an example in which the number of rotations of the θ stage 14 is changed only once, but the number of rotations may be changed any number of times. Further, for example, the control may be performed so that the linear velocity is always constant with Dm = 0.

  In this embodiment, the rotational speed of the θ stage 14 is reduced, but it is not always necessary to reduce the rotational speed, and the rotational speed is set according to the distance in the X-axis direction between the rotational axes of the probe 2 and the θ stage 14. Change it. For example, when the probe 2 is moved from the peripheral part to the central part of the object 22 to be measured, the distance in the X-axis direction between the probe 2 and the rotation axis of the θ stage 14 is shortened, so that the rotational speed is increased.

  The hydrostatic air bearing 4 only needs to be able to hold the probe 2 so as to be movable in the Z-axis direction. For example, the hydrostatic air bearing 4 can be replaced with various guides such as a magnetic bearing and a slide bearing.

  Similarly, the micro linear scale 7 only needs to be able to detect the displacement of the probe 2 with respect to the hydrostatic air bearing, and therefore can be replaced with various displacement meters such as an optical displacement sensor such as a laser length measuring device or a capacitance sensor. is there.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

[Constitution]
The configuration of the second embodiment is also the same as that of the three-dimensional shape measuring instrument 1 to which the three-dimensional shape measuring method according to the first embodiment shown in FIG.

[Action]
Next, the operation of the three-dimensional shape measuring instrument 1 in the second embodiment will be described.

  This embodiment differs from the first embodiment only in the control of the θ stage 14 and the X stage 9 when capturing measurement data, and the other operations are the same.

  That is, when the distance in the X-axis direction between the probe 2 and the rotation axis of the θ stage 14 is L [mm] and the rotation speed of the θ stage 14 is R [round / sec], the linear velocity Vm is (1 ) Vm = 2L × π × R [mm / sec] as shown in the equation. When the linear velocity target value is Sm and the linear velocity allowable range is Dm, the stage control unit 17 changes R so as to satisfy the condition of the above equation (2), that is, Sm−Dm <Vm <Sm + Dm. Is the same as in the first embodiment.

When the moving speed of the X stage 9 is Vx, the measurement data interval Px in the radial direction (X-axis direction) is
Px = Vx / R [mm] (3)
It is. In the second embodiment, the stage control unit 17 further has a target value of the radial measurement data interval Sx, and an allowable range of the radial measurement data interval Dx,
Sx−Dx <Px <Sx + Dx (4)
The moving speed Vx of the X stage 9 is changed so as to satisfy the above.

  That is, the stage control unit 17 rotates the θ stage 14 while scanning the probe 2 along the shape of the object 22 to be measured. At the same time, the stage controller 17 loads the measurement data into the personal computer 18 while driving the X stage 9.

  The stage controller 17 calculates the linear velocity Vm and the radial measurement data interval Px from the position of the probe 2 and the rotational speed of the θ stage 14 while moving the probe 2. When the calculated linear velocity Vm is faster than a prescribed value (that is, Vm> Sm + Dm), the stage control unit 17 sets the rotational speed of the θ stage 14 to the rotational speed R that satisfies Vm> Sm−Dm. Change to, and slow down the rotation speed. Such an operation is the same as in the first embodiment.

  Similarly, when the calculated radial measurement data interval Px is larger than a prescribed value (that is, Px> Sx + Dx), the stage control unit 17 sets the moving speed of the X stage 9 to Px> It changes to the moving speed Vx which becomes Sx-Dx, and makes a moving speed slow.

  By the above operation, spiral measurement data as shown in FIG. 5 is obtained.

  Note that the interval Px and the allowable range Dx of the measurement data in the radial direction are determined by the following method, for example. First, the object to be measured 22 is scanned at a sufficiently small radial measurement data interval Px to measure a three-dimensional shape. Next, a three-dimensional shape measurement is performed by setting an appropriately large radial measurement data interval Px and an allowable range Dx. If there is no difference between the two measurement values obtained in this way, a larger radial measurement data interval Px and an allowable range Dx are set, and the three-dimensional shape is measured again. Conversely, when there is a difference between the two measured values (that is, there is a shape that has not been measured at the large radial measurement data interval Px), a measurement error has occurred. Therefore, in such a case, the smaller measurement data interval Px and allowable range Dx are set in the radial direction, and the three-dimensional shape is measured again. By such a method, it is possible to determine the optimum radial measurement data interval Px and allowable range Dx related to the object 22 to be measured.

  Further, when measuring an object to be measured whose design shape and processing conditions are not so different from the object to be measured 22, it is considered that the optimal radial measurement data interval Px and allowable range Dx are not significantly changed. Therefore, when formulating such an object to be measured, it is also possible to use the same optimal radial measurement data interval Px and allowable range Dx as the object 22 to be measured.

  In this way, the three-dimensional shape of the DUT 22 can be measured.

[effect]
According to the second embodiment as described above, the following effects are obtained.

  Similarly to the description of the effect in the first embodiment, FIGS. 6 to 8 illustrate the case where the control of the θ stage 14 and the X stage 9 is different from FIG. Measurement data is shown. In addition, Px in each figure is an interval of measurement data in the radial direction (X-axis direction) of the peripheral portion of the DUT 22.

  That is, FIG. 6 is the same as the rotational speed of the θ stage 14 and the moving speed of the X stage 9 when measuring the central portion of the object 22 to be measured in FIG. Measurement data when the rotation speed of the θ stage 14 and the moving speed of the X stage 9 are always constant are shown.

  FIG. 7 is the same as the rotational speed of the θ stage 14 and the moving speed of the X stage 9 when measuring the peripheral portion of the device under test 22 in FIG. 5 which is the measurement data of this embodiment, and Measurement data when the rotation speed of the θ stage 14 and the moving speed of the X stage 9 are always constant are shown.

  8 is the same as the moving speed of the X stage 9 when measuring the central portion of the object 22 in FIG. 5 which is the measurement data of the present embodiment, and the moving speed of the X stage 9 is the same. The measurement data is always constant, and the measurement data when the rotation speed of the θ stage 14 is controlled in the same manner as in the present embodiment is shown.

  First, the measurement data of this embodiment shown in FIG. 5 is compared with the measurement data of FIG. In the case of FIG. 6, the linear velocity is equal (Pm6a = Pm5a) at the center portion of the present embodiment. Moreover, the interval of the measurement data in the radial direction of the DUT 22 is also equal (Px6a = Px5a). Therefore, the measurement accuracy is equivalent. On the other hand, in the peripheral part, the linear velocity is faster than that of the present embodiment (Pm6b> Pm5b). Further, in the peripheral portion, the interval of the measurement data in the radial direction of the DUT 22 is equal (Px6b = Px5b). Here, in the case of FIG. 6, since the linear velocity is too high in the peripheral portion, the probe 2 cannot follow the surface shape of the object to be measured 22, and the measurement accuracy is lowered. Therefore, in the case of FIG. 6, the measurement time is shorter than that of the present embodiment because the moving speed of the X stage 9 in the peripheral portion is faster, but the measurement accuracy is reduced in the peripheral portion. Therefore, the present embodiment can reduce a decrease in measurement accuracy at the peripheral portion as compared with the case of FIG. 6, and can realize highly accurate three-dimensional shape measurement.

Next, the measurement data of this embodiment shown in FIG. 5 is compared with the measurement data of FIG. In the case of FIG. 7, for the present embodiment, in the peripheral portion, Ru linear velocity equal (Pm7b = Pm5 b) der. Further, the measurement data interval in the radial direction of the DUT 22 is also equal (Px7b = Px5b). Therefore, the measurement accuracy of the peripheral part is equivalent. On the other hand, in the central portion, the linear velocity is slower than that of the present embodiment (Pm7a <Pm5a). In addition, the measurement data intervals in the radial direction are the same (Px7a = Px5a). However, the linear velocity (Pm5a) at the center of the present embodiment is within the above-described allowable range. Therefore, since the linear velocity at the center of the present embodiment is sufficiently slow, there is no problem that the probe 2 cannot follow and the measurement accuracy is lowered. Therefore, the measurement accuracy is substantially the same at the center. In the case of FIG. 7, the measurement time becomes longer because the moving speed of the X stage 9 in the center is slower than in the present embodiment. Therefore, this embodiment can realize three-dimensional shape measurement with the same measurement accuracy and reduced measurement time as compared with the case of FIG.

  Next, the measurement data of this embodiment shown in FIG. 5 is compared with the measurement data of FIG. In the case of FIG. 8, the linear velocity is equal (Pm8a = Pm5a) at the center of the present embodiment, and the interval between the radial measurement data is also equal (Px8a = Px5a). Therefore, the measurement accuracy at the center is also equivalent. On the other hand, in the peripheral portion, the linear velocity is the same (Pm8b = Pm5b), but the interval between the measurement data in the radial direction is large (Px8b> Px5b). Here, generally, when the interval between measurement data increases to some extent, the shape of the surface cannot be expressed, and the measurement accuracy decreases. Therefore, in the case of FIG. 8, although the measurement time is short because the moving speed of the X stage 9 in the peripheral part is fast, the measurement accuracy is lowered because the interval of the measurement data in the radial direction is too large. Therefore, the present embodiment can reduce a decrease in measurement accuracy of the peripheral portion as compared with the case of FIG. 8, and can realize highly accurate three-dimensional shape measurement.

  As described above, in the present embodiment, by controlling the linear velocity to be within a certain range, the probe 2 is close to the limit at which the probe 2 can follow the device under test 22 at both the center and the periphery of the device under test 22. It is possible to scan at a linear velocity. Furthermore, by controlling the interval between the measurement data in the radial direction to be within a certain range, it is possible to reduce a measurement error caused by the coarse interval between the measurement data.

  Therefore, according to this embodiment, it is possible to realize measurement of a three-dimensional shape that reduces the measurement error in the peripheral portion and shortens the measurement time as much as possible.

[Modification]
In addition, naturally each deformation | transformation of this 2nd Embodiment can be variously changed and changed.

  For example, in this embodiment, the measurement is performed after the optical axes of the probe 2 and the object to be measured 22 are substantially matched. However, any part of the object to be measured 22 can be obtained as long as measurement data of the entire object to be measured 22 can be acquired. Measurement may be performed from

  In the present embodiment, the example in which the rotation speed of the θ stage 14 and the moving speed of the X stage 9 are changed only once is shown, but the change may be performed any number of times. Further, it is not always necessary to intermittently change the rotational speed of the θ stage 14 and the moving speed of the X stage 9. For example, assuming that Dm = Ds = 0, control may be performed to change the rotational speed and the moving speed in a substantially stepless manner so that the interval between the linear velocity and the measurement data in the radial direction is always constant.

  In this embodiment, the stage control unit 17 decreases the rotational speed of the θ stage 14 and changes the moving speed of the X stage 9 to be slower. However, as in the first embodiment, the number of rotations of the θ stage 14 may be changed according to the distance in the X direction between the rotation axis of the probe 2 and the θ stage 14. Further, the moving speed of the X stage 9 may be changed according to the rotational speed of the θ stage 14. For example, when the probe 2 is moved from the peripheral part of the object to be measured 22 toward the center part, the distance in the X direction of the rotation axis between the probe 2 and the θ stage 14 is shortened. Make it high. When the rotation speed of the θ stage 14 is increased, the moving speed of the X stage 9 is increased.

  In the present embodiment, the rotation speed of the θ stage 14 and the moving speed of the X stage 9 are simultaneously changed. However, it is not always necessary to change the rotation speed at the same time. The moving speed of the stage 9 may be changed.

  When changing the rotation speed of the θ stage 14 or the moving speed of the X stage 9, there may be a case where minute vibrations occur due to the speed change, resulting in a measurement error in the measured value. If this measurement error is extremely large, the operator can determine that the measurement error is due to vibration at the time of speed change, so that data can be deleted on the software of the personal computer 18 after the measurement is completed. However, when the vibration due to the speed change is extremely small, the measurement error is also small. Therefore, the operator may not be able to determine whether it is the actual shape of the object 22 or a measurement error due to vibration when the speed changes. In order to solve this problem, a command signal for changing the rotational speed of the θ stage 14 and the moving speed of the X stage 9 is taken into the personal computer 18 together with the length measurement value. Then, after the measurement is completed, measurement data in a certain range before and after the timing of speed change is deleted by software. As a result, measurement errors due to vibration at the time of speed change can be reduced, so that more accurate three-dimensional shape measurement can be performed.

  In addition, the range which deletes measurement data is determined in the following procedures, for example. First, a measurement object is a reference sphere that is processed with high accuracy and can be regarded as a spherical surface almost as designed. The three-dimensional shape of the reference sphere is measured under the condition that there is a speed change during the shape measurement. Then, the deviation between the measurement data of the portion where the speed has changed and the design shape of the reference sphere is calculated. Here, the deviation from the design shape before and after the speed change is a measurement error caused by vibration. Therefore, a range in which a difference from the design shape is generated before and after the timing of the speed change is recorded, and this is set as a range from which measurement data is deleted and stored in the personal computer 18.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present invention. .

(Appendix)
The invention having the following configuration can be extracted from the specific embodiment.

(1) a step of rotating the object to be measured in the θ direction by a rotation mechanism and measuring the rotation angle θ;
Measuring the position coordinates of the probe while moving the probe moving along the shape of the object to be measured in the X direction substantially orthogonal to the rotation axis of the rotating mechanism and holding the probe at a predetermined position in the X direction; ,
Changing the number of rotations of the rotation mechanism;
Have
The step of changing the rotation speed of the rotation mechanism is such that the rotation speed of the rotation mechanism decreases as the distance in the X direction between the rotation shaft of the rotation mechanism and the probe increases.
A three-dimensional shape measuring method characterized by the above.

(Corresponding embodiment)
The three-dimensional shape measuring method described in (1) corresponds to the first embodiment.

(Function and effect)
According to the three-dimensional shape measuring method described in (1), the longer the distance in the X direction between the rotating shaft of the rotating mechanism and the probe, the lower the number of rotations of the rotating mechanism is controlled. The difference in the linear velocity between the center part of the object and the peripheral part becomes small. As a result, the linear velocity is increased at the peripheral portion, so that the measurement error due to the probe being unable to follow the minute unevenness of the object to be measured can be reduced. In addition, since scanning can be performed at a linear velocity close to the limit at which the probe can follow the object to be measured in both the central portion and the peripheral portion, the measurement time can be shortened as much as possible without reducing the measurement accuracy.

  Therefore, according to the three-dimensional shape measurement method described in (1), it is possible to realize three-dimensional shape measurement with a reduced measurement error and a short measurement time.

(2) rotating the object to be measured in the θ direction by a rotation mechanism and measuring the rotation angle θ;
A step of measuring a position coordinate of the probe by moving a probe moving along the shape of the object to be measured rotated by the rotation mechanism in the X direction substantially orthogonal to the rotation axis of the rotation mechanism;
Changing the rotational speed of the rotating mechanism and the moving speed of the probe in the X direction;
Have
The step of changing the number of rotations and the moving speed is such that the longer the distance in the X direction between the rotation shaft of the rotation mechanism and the probe, the lower the number of rotations of the rotation mechanism and the movement of the probe in the X direction. Slow down,
A three-dimensional shape measuring method characterized by the above.

(Corresponding embodiment)
The second embodiment corresponds to the embodiment relating to the three-dimensional shape measuring method described in (2).

(Function and effect)
In the three-dimensional shape measuring method described in (2), the longer the distance in the X direction between the rotating shaft of the rotating mechanism and the probe, the lower the number of rotations of the rotating mechanism is controlled. The difference between the linear velocities of the central and peripheral probes is reduced. As a result, the linear velocity is increased at the peripheral portion, so that the measurement error due to the probe being unable to follow the minute unevenness of the object to be measured can be reduced. In addition, since scanning can be performed at a linear velocity close to the limit at which the probe can follow the object to be measured in both the central portion and the peripheral portion, the measurement time can be shortened as much as possible without reducing the measurement accuracy.

  In addition, the longer the distance in the X direction between the rotating shaft of the rotating mechanism and the probe, that is, the lower the rotational speed of the rotating mechanism, the slower the moving speed of the probe in the X direction is controlled. The difference in the distance between the measurement data in the radial direction between the central part and the peripheral part of the object becomes small. Thereby, the measurement error which arises when the space | interval of measurement data becomes coarse can be reduced.

  Therefore, according to the three-dimensional shape measurement method described in (2), it is possible to realize three-dimensional shape measurement with a reduced measurement error and a short measurement time.

(3) The method further includes a step of processing measurement data of the object to be measured, which includes the rotation angle θ of the rotation mechanism and the position coordinates of the probe,
The step of processing the measurement data deletes the measurement data before and after the timing of changing the rotational speed of the rotating mechanism or the moving speed of the probe in the X direction within a specified range.
(3) The three-dimensional shape measuring method according to (2).

(Corresponding embodiment)
The second embodiment corresponds to the embodiment relating to the three-dimensional shape measuring method described in (3).

(Function and effect)
The three-dimensional shape measuring method described in (3) is caused by a change in speed by deleting measurement data before and after the timing at which the rotational speed of the rotating mechanism or the moving speed of the probe in the X direction is changed within a specified range. Measurement errors due to minute vibrations can be reduced.

  Therefore, according to the three-dimensional shape measurement method described in (3), in addition to the effect of (2), it is possible to realize measurement of a three-dimensional shape that further reduces measurement errors.

(4) a rotation angle measuring means for rotating the object to be measured in the θ direction by a rotation mechanism and measuring the rotation angle θ;
A probe position for measuring the position coordinate of the probe while moving the probe moving along the shape of the object to be measured in the X direction substantially orthogonal to the rotation axis of the rotating mechanism and holding the probe at a predetermined position in the X direction. Coordinate measuring means;
A rotation speed changing means for changing the rotation speed of the rotation mechanism;
Have
The rotation speed changing means decreases the rotation speed of the rotation mechanism as the distance in the X direction between the rotation shaft of the rotation mechanism and the probe is longer.
A three-dimensional shape measuring apparatus.

(Corresponding embodiment)
The three-dimensional shape measuring apparatus described in (4) corresponds to the first embodiment.

(Function and effect)
According to the three-dimensional shape measuring apparatus described in (4), the longer the distance in the X direction between the rotating shaft of the rotating mechanism and the probe, the lower the number of rotations of the rotating mechanism is controlled. The difference in the linear velocity between the center part of the object and the peripheral part becomes small. As a result, the linear velocity is increased at the peripheral portion, so that the measurement error due to the probe being unable to follow the minute unevenness of the object to be measured can be reduced. In addition, since scanning can be performed at a linear velocity close to the limit at which the probe can follow the object to be measured in both the central portion and the peripheral portion, the measurement time can be shortened as much as possible without reducing the measurement accuracy.

  Therefore, according to the three-dimensional shape measuring apparatus described in (4), it is possible to realize three-dimensional shape measurement with a reduced measurement error and a short measurement time.

(5) a rotation angle measuring means for rotating the object to be measured in the θ direction by a rotation mechanism and measuring the rotation angle θ;
Probe position coordinate measuring means for measuring a position coordinate of the probe by moving a probe that moves along the shape of the object to be measured rotated by the rotation mechanism in an X direction substantially orthogonal to the rotation axis of the rotation mechanism; ,
Changing means for changing the rotational speed of the rotating mechanism and the moving speed of the probe in the X direction;
Have
The changing means decreases the rotational speed of the rotating mechanism and slows the moving speed of the probe in the X direction as the distance in the X direction between the rotating shaft of the rotating mechanism and the probe is longer.
A three-dimensional shape measuring apparatus.

(Corresponding embodiment)
The embodiment relating to the three-dimensional shape measuring apparatus described in (5) corresponds to the second embodiment.

(Function and effect)
In the three-dimensional shape measuring apparatus described in (5), the longer the distance in the X direction between the rotating shaft of the rotating mechanism and the probe, the lower the number of rotations of the rotating mechanism is controlled. The difference between the linear velocities of the central and peripheral probes is reduced. As a result, the linear velocity is increased at the peripheral portion, so that the measurement error due to the probe being unable to follow the minute unevenness of the object to be measured can be reduced. In addition, since scanning can be performed at a linear velocity close to the limit at which the probe can follow the object to be measured in both the central portion and the peripheral portion, the measurement time can be shortened as much as possible without reducing the measurement accuracy.

  In addition, the longer the distance in the X direction between the rotating shaft of the rotating mechanism and the probe, that is, the lower the rotational speed of the rotating mechanism, the slower the moving speed of the probe in the X direction is controlled. The difference in the distance between the measurement data in the radial direction between the central part and the peripheral part of the object becomes small. Thereby, the measurement error which arises when the space | interval of measurement data becomes coarse can be reduced.

  Therefore, according to the three-dimensional shape measuring apparatus described in (5), it is possible to realize three-dimensional shape measurement with a reduced measurement error and a short measurement time.

(A) is a figure which shows the structure of the three-dimensional shape measuring machine to which the three-dimensional shape measuring method which concerns on 1st Embodiment of this invention was applied, (B) is acquired by the three-dimensional shape measuring machine of (A). It is a figure which shows the measured data. It is a figure which shows the structure of the laser length measuring device as a Z laser length measuring device and a X laser length measuring device. It is a figure which shows the measurement data when it is the same as the rotation speed of the (theta) stage at the time of measuring the center part of the to-be-measured object in FIG. 1 (B), and the rotation speed of (theta) stage is always constant. It is a figure which shows the measurement data when it is the same as the rotation speed of the (theta) stage at the time of measuring the peripheral part of the to-be-measured object in FIG. 1 (B), and the rotation speed of (theta) stage is always constant. It is a figure which shows the measurement data acquired by the three-dimensional shape measuring machine to which the three-dimensional shape measuring method which concerns on 2nd Embodiment of this invention was applied. Measurement data in the case where the rotational speed of the θ stage and the moving speed of the X stage when measuring the central part of the object to be measured in FIG. 5 are the same, and the rotational speed of the θ stage and the moving speed of the X stage are always constant. FIG. Measurement data when the rotation speed of the θ stage and the movement speed of the X stage at the time of measuring the peripheral portion of the object to be measured in FIG. 5 are the same, and the rotation speed of the θ stage and the movement speed of the X stage are always constant. FIG. The X stage moving speed is the same as the X stage moving speed when measuring the central part of the object to be measured in FIG. 5 and the X stage moving speed is always constant, and the rotation speed of the θ stage is controlled in the same manner as in FIG. It is a figure which shows the measurement data at the time of doing. It is a figure which shows roughly the basic composition of the three-dimensional shape measuring machine of a R (theta) scanning system. It is a figure which shows the measurement data acquired by the three-dimensional shape measuring machine of FIG. It is a figure which shows the measurement data acquired by the three-dimensional shape measuring machine of FIG. 9 by another measurement data acquisition method. It is a figure which shows the measurement data at the time of reducing the rotation speed of (theta) stage.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 ... Three-dimensional shape measuring machine, 2 ... Probe, 3 ... Tip ball, 4 ... Static pressure air bearing, 5 ... Leaf spring, 6 ... Leaf spring holding part, 7 ... Micro linear scale, 7a ... Scale part, 7b ... Reading Part, 8 ... Z stage, 9 ... X stage, 10 ... Z laser length measuring device, 10a, 11a, 50a ... length measuring part, 10b, 11b, 50b ... prism part, 11 ... X laser length measuring device, 12 ... Z Reference mirror, 13 ... X reference mirror, 14 ... θ stage, 15 ... θ rotary encoder, 16 ... Frame, 17 ... Stage controller, 18 ... Personal computer, 19, 20, 21, 59 ... Right-angle reflecting prism, 22 ... Subject Measured object, 50 ... laser length measuring device, 50c ... length measuring axis, 51, 58 ... plane mirror, 52 ... laser light source, 53 ... receiver, 54 ... polarizing plate, 55 ... polarizing beam splitter, 56, 57 ... λ / 4 plate.

Claims (4)

A step of rotating the object to be measured in the θ direction by a rotation mechanism and measuring the rotation angle θ;
A step of moving a probe that moves along the shape of the object to be measured rotated by the rotation mechanism in the X direction substantially orthogonal to the rotation axis of the rotation mechanism, and measuring the position coordinates of the probe;
The longer the distance in the X direction between the rotating shaft of the rotating mechanism and the probe, the lower the rotational speed of the rotating mechanism and the slower the moving speed of the probe in the X direction. Changing the number and the moving speed of the probe in the X direction;
Obtaining measurement data of the object to be measured obtained from the position coordinates of the probe, and an instruction signal for changing at least one of the rotational speed of the rotating mechanism and the moving speed of the probe in the X direction;
Deleting the measurement data of the object under measurement before and after the timing of changing at least one of the rotational speed and the moving speed based on the acquired instruction signal; and
3-dimensional shape measuring method characterized by comprising a. The step of deleting includes
Measuring a three-dimensional shape of a reference sphere that can be regarded as a spherical surface as designed;
Calculating a deviation between the measurement data of the reference sphere and the design shape of the reference sphere before and after the timing at which at least one of the rotation speed and the moving speed is changed based on the instruction signal;
Storing the range in which the deviation occurs as a range to delete the measurement data of the object to be measured;
Deleting the measurement data of the device under test in the stored range;
The three-dimensional shape measuring method according to claim 1, comprising: A probe that moves along the shape of the object to be measured;
A rotating mechanism you want to rotate. The object to be measured in θ direction,
Rotation angle measuring means for measuring the rotation angle θ of the object to be measured ;
The probe was moved to the rotation axis and the X direction substantially perpendicular of the rotary mechanism, and the probe position coordinate measuring means for measuring the position coordinates of the probe,
The longer the distance in the X direction between the rotating shaft of the rotating mechanism and the probe, the lower the rotational speed of the rotating mechanism and the slower the moving speed of the probe in the X direction. Changing means for changing the number and the moving speed of the probe in the X direction;
Obtaining measurement data of the object to be measured obtained from the position coordinates of the probe, and an instruction signal for changing the rotational speed of the rotating mechanism and the moving speed of the probe in the X direction, and based on the instruction signal, A computer that deletes the measurement data of the object to be measured before and after the timing of changing the rotation speed and the moving speed within a specified range;
3-dimensional shape measuring apparatus comprising: a. The object to be measured includes a reference sphere that can be regarded as a spherical surface as designed,
The computer calculates a deviation between the measurement data of the reference sphere and the design shape of the reference sphere before and after the timing at which at least one of the rotational speed of the rotation mechanism and the moving speed of the probe is changed based on the instruction signal. Calculating, storing the range in which the deviation occurs as a range to delete the measurement data of the measurement object, and deleting the measurement data of the measurement object in the stored range;
The three-dimensional shape measuring apparatus according to claim 3.

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