JPH07190734A - Circumferential surface profile measuring method - Google Patents

Abstract

PURPOSE:To provide a device which can make measurement with high accuracy with the number of measurements lessened as much as possible in a profile measurement for the inner surface of an outer cylinder and the like. CONSTITUTION:The profiles of cylindrical surfaces 3 and 5 are computed based on a space distribution between the cylindrical surfaces 3 and 5 when the outer and inner cylinders 2 and 3 are coaxially disposed, a space distribution between the cylindrical surfaces 3 and 5 when the outer cylinder 2 or the inner cylinder 4 is rotated by 180 deg., and the inner diameter distribution of the outer cylinder 2 or the outer diameter distribution of the inner cylinder 4. For example, a space between the inner surface 3 of the outer cylinder and the outer surface 5 of the inner cylinder is measured by a space measuring interferometer 1 so as to allow a measured value to be obtained, and the same measurement is performed after the outer cylinder 2 has been rotated by 180 deg. so as to allow a measured value to be obtained. A measured value for the inner surface diameter of the outer cylinder 2 can be obtained by the interferometer with the inner cylinder 4 removed. The profile of each cylindrical surface can be accurately measured by computing the profile of a measured cylindrical surface with the aid of a space measuring means making use of the space measuring interferometer and the like based on measured values for the three kinds of cylindrical surface spaces for two cylinders, that is, a combination of the outer cylinder 2 and the inner cylinder 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circumferential surface shape measuring method, and more particularly to a measuring method suitable for highly accurately measuring a cylindrical surface.

[0002]

2. Description of the Related Art For absolute measurement of the shape of a cylindrical surface, the cylindrical surface measuring device measures the cylindrical surface of the object to be measured, and then the object to be measured is rotated at a constant angle with respect to the measuring device. Then, there is a method in which a series of measurements are sequentially performed in the same procedure and the shape error is measured from the obtained measurement values.

[0003]

However, this method requires a large number of measurement times, and the measurement and analysis take a long time.

The present invention therefore seeks to provide a method for measuring with high accuracy and with as few measurements as possible.

[0005]

According to the measuring method of the present invention, an outer cylinder and an inner member having an outer peripheral surface having a diameter smaller than that of the inner peripheral surface of the outer cylinder are coaxially arranged. The space distribution on both circumferential surfaces of the outer cylinder or inner member 180
It is characterized in that the shape of the circumferential surface is calculated from the distribution of the intervals between the two circumferential surfaces in the state of being rotated by one degree and the distribution of the inner diameter of the outer cylinder or the outer diameter of the inner member.

[0006]

In the above-described shape measuring method according to the present invention, when measuring the shape of the circumferential surface, the distance between the surfaces is basically measured. The distribution of the intervals on both circumferential surfaces,
Even when obtaining the space distribution of both circumferential surfaces in the state of being rotated by 180 degrees, and the distribution of the inner diameter of the outer cylinder and the like, it is possible to measure the surface distance. The circumferential surface is calculated by calculating the shape of the circumferential surface to be measured from the measured values of the three types of surface spacing when the outer cylinder and the inner member are combined by distance measurement using an interferometer for distance measurement or an electric micrometer. Accurately measure the shape.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention. In the figure,
Reference numeral 1 denotes an interval measuring device, and for this, for example, an interval measuring interferometer whose example is described later can be preferably used.
Alternatively, an electric micrometer or the like may be used. Further, 2 denotes an outer cylinder, and 4 denotes, for example, an inner cylinder having an outer circumferential surface having a diameter smaller than the inner diameter of the outer cylinder 3.

As shown in FIG. 1, the gap measuring device 1 includes an inner surface 3 (inner circumferential surface) of an outer cylinder 2 and an outer surface 5 of an inner cylinder 4 as shown in FIG.
The outer cylinder inner surface 3 and the inner cylinder outer surface 5 are arranged by being arranged between (outer circumferential surfaces). In this embodiment, the distance measuring device 1 is used in each of the measurement modes of FIGS. 1 and 2, but in any case, it measures the distance between the surfaces. The present measuring method is based on measuring the distance between the two surfaces as described above.

As shown in FIG. 1, the outer cylinder 2 and the inner cylinder 4 are arranged so that the outer cylinder 2 and the inner cylinder 4 are coaxial with each other. Further, the outer cylinder 2 or the inner cylinder 4 is rotatable around an axis, and here, the outer cylinder 2 is rotatable.

In the present example, the distance distribution between the two cylindrical surfaces with the outer cylinder 2 and the inner cylinder 4 arranged coaxially is measured by the distance measuring device 1.

Now, the surface shapes of the outer cylinder inner surface 3 and the inner cylinder outer surface 5 are e ₁ (z, θ) and e ₂ (z, θ), respectively. Here, regarding the coordinates, the cylindrical axis (the direction perpendicular to the paper surface in FIGS. 1 and 2) is z, and the angle of the radius vector is represented by θ as shown in FIGS. The x and y planes are the planes orthogonal to the z axis.

To obtain the distance distribution, the distance measuring device 1 is arranged between the outer cylinder 2 and the inner cylinder 4 as shown in FIG. 1, and for example, the distance measuring device 1 is placed on the same z coordinate position. , Rotate around the axis once (360 degrees) (scan) to measure the distance, and also move (scan) the distance measuring instrument 1 in the z coordinate direction to change z. You can do that. At this time, in this example, the outer cylinder 2 and the inner cylinder 4 are
Do not move during such a scan. Therefore, during this period, the relative opposing positions in both the circumferential direction and the axial direction do not change.

The distance distribution is measured once at an arbitrary opposed position of the outer cylinder 2 and the inner cylinder 4 so as to reduce the error, and the outer cylinder 2 and the inner cylinder 4 are relatively moved 180 degrees.
After being rotated by 180 degrees, that is, in this example, the inner cylinder 4 is left at the same position and only the outer cylinder 2 is once rotated about the axis by 180 degrees, and the opposing positions of both are shifted by half a rotation. , Do it one more time. Therefore, it may be performed twice in total.

As will be described below using equations, as described above, the measured value of the distance between the outer cylinder 2 and the inner cylinder 4 at a certain opposing position, where the coordinate z and the radial angle θ are as described above. Let W ₁ (x, y) be the following relationship.

[0015]

[Equation 1]

Further, the outer cylinder 2 is rotated 180 degrees (=
When the same measurement is performed after (π) rotation (θ + π) and the obtained measured value is W ₂ (x, y), the following relationship holds.

[0017]

[Equation 2]

Here, regarding the above equations (1) and (2),
Then ε_i(I = 1 or 2) , Θε _i(I = 1 or
2) (Note that "θε_i”In the notation
Represents the relative eccentricity of the cylinder, and ε_i
Is the amount of eccentricity, θε_iIndicates the direction of eccentricity. Also,
k_i(I = 1 or 2), θk_i(I = 1 or 2)
(Here, "θk_iThe "k" part in the notation
Represents the relative inclination of the cylinder, k_iIs inclined
Mushroom coefficient, θk_iIndicates the direction of inclination. these
The value of each is unknown. Eccentricity and inclination are small
Due to the displacement of the opposing cylindrical surfaces due to this
The measurement error due to the above shall be negligible.

Thus, the above W ₁ (x, y) and W ₂ (x, y)
And the outer cylinder 2 and the inner cylinder 4 are arranged so as to be coaxial with each other.
Similarly, with respect to the spacing distribution of both cylindrical surfaces when the outer cylinder 2 is rotated by 180 degrees around the axis in the coaxial arrangement, these can be obtained by using the spacing measuring device 1 in the measurement mode as shown in FIG. .

In this measuring method, another type, that is, the distance between the cylindrical surfaces is measured and used as the basis for calculating the shape of the cylindrical surface to be measured. This can be done by obtaining the distribution of the inner diameter of the outer cylinder 2 or the outer diameter of the inner cylinder 4, but in this embodiment, the inner diameter of the outer cylinder 2 is measured. Also in this case, the distance between the surfaces is measured. FIG. 2 shows an example of measuring the inner diameter distribution of the outer cylinder 2 in that case.

In this figure, unlike FIG. 1, the inner cylinder 4 is removed from the inside of the outer cylinder 2, and the measurement is performed in this state. With respect to the distance measuring instrument 1, scanning this around the axis and scanning in the z coordinate direction is the same as that described above. Figure 2
, The measured value of the inner surface diameter of the outer cylinder 2 is W ₃ (x, y)
Then, the relation of the following equation is obtained.

[0022]

[Equation 3]

In this way, the measured value W ₃ (x, y) is obtained, which can also be obtained by using the interval measuring device 1 in the measuring manner as shown in FIG.

Thus, the above equations (1), (2),
From the equation (3), the following equations (4) and (5) are obtained.

[0025]

[Equation 4]

[0026]

[Equation 5]

The above are measured values W ₁ (x, y), W ₂ (x, y), W ₃ (x,
It means that the surface shapes e ₁ (z, θ) and e ₂ (z, θ) can be calculated based on y). Here, (4)
In the equation (5), ε and ε'are k,
k'is a quantity derived from the above-mentioned slope coefficient,
It is an amount irrelevant to the shape error of the cylindrical surface, and may be appropriately determined when the shape is finally displayed.

Thus, the shape measuring method according to the present embodiment
Is measured by a distance measuring device that uses an interferometer for distance measurement.
Two cylinders by the method of measuring the distance between the surfaces
That is, three types of cylinders when the outer cylinder 2 and the inner cylinder 4 are combined
Measured value of surface spacing W₁(x, y), W ₂(x, y), W₃get (x, y)
From these, the cylindrical surface to be measured according to the above equations (4) and (5)
Can be calculated, and calculated in this way
This makes it possible to measure the cylindrical surface shape with high accuracy.
It Highly accurate measurements can be made with the fewest number of measurements
This measurement method is simple and requires less time.
It is practical.

Next, another embodiment of the present invention will be described. In the embodiment according to FIGS. 1 and 2, the diameter of the inner surface 3 of the outer cylinder is measured, and the other two measurement values W ₁ (x, y) and W ₂ (x, y) and the cylindrical surface are used. However, it goes without saying that the diameter of the outer surface 5 of the inner cylinder may be measured instead of the measurement on the inner surface of the outer cylinder.

The present embodiment measures the distribution of the outer diameter of the inner cylinder 4, and FIG. 3 shows an example for measuring the inner cylinder. In the figure, reference numerals 130, 131, 132 and 133 denote reflecting mirrors, respectively, which are arranged on the turntable 134 so that the optical path of the distance measuring interferometer 1 as a distance measuring device passes through one diameter of the inner cylinder 4. Has been done. Although not described in detail, the rotary table 134 itself is configured to rotate around the axis of the inner cylinder 4. Therefore, such a turntable 1
By rotating 34, the diameter distribution of the inner cylinder 4 can be measured. Also in this case, the distance between the surfaces is measured. The outer diameter of the inner cylinder 4 can also be measured in this way. It can be easily understood that in order to calculate the shape distribution, the shape of the inner surface of the outer cylinder and the shape of the outer surface of the inner cylinder in the above embodiment may be interchanged. The present invention may be implemented in this manner.

In each of the above embodiments, in measuring the space distribution of the cylindrical surface, the outer cylinder inner diameter or the inner cylinder outer diameter distribution,
That is, in obtaining the measured values of W ₁ (x, y) and W ₂ (x, y) and the measured values of W ₃ (x, y), the scanning method is fixed cylinder and the interval measurement. The instrument 1 is rotated around the axis, and the measurement may be performed in that way, or, conversely, the interval measuring instrument is fixed for scanning and the cylinder side is the axis. It may be rotated around.

Next, an example of the configuration of a suitable interferometer for measuring the distance, which can be used as the distance measuring device in each of the above embodiments, will be shown. FIG. 4 shows an embodiment of the interferometer for measuring the distance for measuring the surface distance, which was devised by the present inventor, but it goes without saying that other types of interferometers can be used. Hereinafter, the operation of the interferometer will be described together with the configuration shown in FIG. The figure shows the inner surface 3 of the outer cylinder and the outer surface 5 of the inner surface.
The state when measuring the surface spacing between both cylindrical surfaces of is shown,
The interferometer 1 includes a light source (not shown), polarization prisms 101, and 1.
/ 4 wavelength plates 102, 103, polarizing plate 104, light receiving element 9
Etc. One polarization prism 101 and one light receiving element 105 are arranged in this order from the light source side as shown.

The polarizing prism 101 has one polarizing film, and quarter-wave plates 102 and 103 for rotating the plane of polarization on each side facing the cylindrical surface 3 and the cylindrical surface 5.
However, the polarizing plate 10 is provided on the side facing the light receiving element 105.
4 are provided integrally with the polarization prism 101, respectively. The quarter-wave plates 102 and 103 are used for the polarization prism 10.
1 and the cylindrical surfaces 3 and 5, the polarizing plate 104 is
It is in the optical path from the polarizing prism 101 to the light receiving element 105. Each of the quarter-wave plates 102 and 103 faces the cylindrical surface 3 of the outer cylinder so that the polarization plane of the transmitted polarization component is rotated. In the azimuth direction and facing the cylindrical surface 5 of the inner cylinder 1 /
The four-wavelength plate 103 is selected such that the crystal axis thereof is in the direction of 45 degrees with respect to the paper surface, and the polarization axis of the four-wavelength plate 103 is selected in the plane other than the paper surface and the plane perpendicular thereto.

A small-diameter laser light beam enters the polarizing prism 101 from the light source side. Since the resolution of measurement is determined by the size of the light flux, the light flux should be as small as possible. Also, because the number of sample points for measurement is adjusted,
It is desirable that this incident light beam be parallel to the z direction by using a cylindrical lens and be converged on the cylindrical axis in the radial direction as shown in the drawing. Here, the laser light beam is a light beam from a two-frequency laser having p-polarized light that vibrates at a frequency f1 in the paper surface and s-polarized light that vibrates at a frequency f2 perpendicularly to the paper surface.

In the above structure, the s-polarized light component of the p-polarized light and the s-polarized light from the two-frequency laser is used as the measurement light beam that reciprocates between the cylindrical surface 3 and the cylindrical surface 5, and the p-polarized light component is used as the reference light beam. Then, the measurement is performed as described below. In this case, the split measurement light flux of the s-polarized light component is combined with the reference light flux of the p-polarized light component with an optical path length difference corresponding to the distance between the cylindrical surfaces 3 and 5.
These surface distances will be reflected in this optical path difference.

Now, when a light beam is incident from the above laser,
The s-polarized component incident on the polarizing prism 101 is reflected by the polarizing film of the polarizing prism 101, passes through the quarter-wave plate 102, reaches the cylindrical surface 3, and is reflected by the cylindrical surface 3. The light thus reflected again passes through the quarter-wave plate 102. Here, the polarized light changes to p-polarized light, so this time the polarizing prism 10
It passes through the polarizing film of No. 1 and goes to the inner cylinder side.
The light passes through the four-wave plate 103 and is reflected by the inner cylindrical surface 5. After passing through the quarter-wave plate 103 again after being reflected, it becomes s-polarized light in the above process, and as a result, the polarization prism 10
The light receiving element 1 is reflected by the polarizing film 501 of No. 1 and passes through the polarizing plate 104 in the plane other than the plane of the paper and the plane perpendicular to it.
Enter 05. In this way, the s-polarized light component of the measurement light beam reciprocates in the optical path between the cylindrical surfaces.

On the other hand, the p-polarized light of the reference light flux reaches the light receiving element 9 without passing through the same optical path. That is, the incident p-polarized light passes through the polarizing prism 101 and the polarizing plate 104, and the light receiving element 1
05, and interferes with the above-mentioned s-polarized light that reciprocates between the cylindrical surface 3 and the cylindrical surface 5, and obtains a beat signal equal to the difference between the two frequencies f1 and f2. As is well known, when the interferometer is moved so as to rotate about an axis in the xy plane along a predetermined path, the optical path accompanying the movement is measured by measuring the phase change of this beat signal. The change in length can be measured. Since this measurement method is known as the heterodyne interferometry method, further explanation is omitted, but the phase change of the beat signal during scanning as described above is measured as the change in the distance between the two cylindrical surfaces 3 and 5. You can

As described above, the interplanar distance can be accurately measured by the interferometer of the present structure having the measurement light beam that reciprocates the optical path extending between the cylindrical surfaces 3 and 5 and the reference light beam that does not pass through the optical path. When using such an interferometer,
Each of the above-mentioned three types of measured values can be obtained as such, and as a result, there is an advantage that the cylindrical surface shape can be measured with higher accuracy. Also, the interferometer itself is small and easy to manufacture. This cylindrical surface shape measuring method is based on measuring the distance between the surfaces when measuring the shape of the cylindrical surface, and in this case, the above-mentioned distance measurement according to the previous development of the present inventor. The interferometer 1 for use can provide an interferometer suitable for measuring the interplanar distance, and is very effective for practical application of precision length measurement. The need to measure the shape of the cylindrical surface with high accuracy is increasing, and a measurement method that can easily guarantee the order of nanometers is required. However, the cylindrical surface shape measuring method using the interferometer 1 for measuring the interval is required. Can easily realize a method of accurately measuring a cylindrical surface with such accuracy. The small interferometer is advantageous in that the smaller the interferometer is when it is moved and scanned to measure the shape, and it is also useful for easily enabling proper scanning.

When scanning is performed by moving the interferometer, the laser part and other interferometer components are moved integrally for measurement, or the laser is fixed and other interferometer components are used. There are two possible ways to move only the part, whichever is possible. In any case, those skilled in the art can easily determine how to configure the measurement system, if necessary.

FIG. 5 shows another embodiment which is suitable for use as the interferometer 1 for measuring the distance for measuring the surface distance. The difference from the case of FIG. 4 is that the lens 106 and the lens 10 that collect the light flux on the cylindrical surfaces 3 and 5 of the outer cylinder and the inner cylinder, respectively.
7 has been inserted. Interferometer 1 with this configuration
In addition to the above-mentioned advantages, the use of can provide high resolution corresponding to the size of the focused light spot because the light flux is focused. The focal lengths of the two lenses need not be equal.

Even when the interferometer 1 of FIGS. 4 and 5 is used as a distance measuring device, as described above, in scanning, the cylindrical side is fixed and the interferometer 1 is rotated about the axis for measurement. Alternatively, the interferometer 1 may be fixed and the cylinders (both the inner cylinder and the outer cylinder in the case of the measurement modes of FIGS. 4 and 5) may be rotated around the axis for scanning.

Next, the overall structure of the cylindrical surface measuring apparatus suitable for carrying out the present measuring method will be described. FIG. 6 shows an embodiment of the measuring device when the cylindrical surface is installed in the vertical direction. In this case, the scanning is also an example in which the distance measuring interferometer is rotated around the axis.

In the figure, the device comprises a laser 6.
The laser 6 may be a dual frequency laser as described above. The light flux from the laser 6 passes through the reflecting mirrors 7, 8, 9 and the lens 108, and the polarization prism 101 of the interferometer 1 for measuring the distance.
Is incident on the main body including. Here, the illustrated interferometer 1 is
It is of the embodiment described in FIG. 5 with lenses 106 and 107. The interferometer 1 used may be of the type described with reference to FIG.

The interval measuring interferometer 1 includes an outer cylinder 2 and an inner cylinder 4.
It is fixed to the tip of the holding arm 10 that can be inserted into the space formed by the two cylinders. Here, the outer cylinder 2 and the inner cylinder 4 are arranged coaxially. The base of the holding arm 10 for the distance measuring interferometer is fixed to a precise rotating body 11 equipped with a known rotation angle measuring device (not shown).

The bearing of the rotating body 11 is in the Z-axis direction with respect to the column 12 (the vertical direction in FIG. 6, which is the vertical direction).
It is fixed to a moving table 13 that slides into the. Stanchion 12
The relative movement amount of the moving table 13 and the moving table 13 can be measured with high accuracy by a measuring device (not shown) according to a known method. The column 12 is fixed to the base 14. The cylinders 2 (outer cylinder) and / or 4 (inner cylinder) that are the objects to be measured are mounted on the base 14 by a known mounting method.

With such a device, the distance between the cylindrical surface 3 of the outer cylinder 2 and the cylindrical surface 5 of the inner cylinder 4 can be measured while rotating the distance measuring interferometer 1 and moving it in the Z-axis direction.
If this is done at an arbitrary position where the outer cylinder 2 and the inner cylinder 4 face each other, then the same measurement can be performed with the outer cylinder 2 or the inner cylinder 4 rotated by 180 degrees around the axis. Then, for example, when the inner diameter of the outer cylinder 2 is measured as shown in FIG. 2, the inner cylinder 4 may be removed and the outer cylinder 2 alone may be used. Spatial distribution of the cylindrical surfaces 3 and 5 when the outer cylinder 2 and the inner cylinder 4 are coaxially arranged, and both cylindrical surfaces when the outer cylinder 2 or the inner cylinder 4 is rotated by 180 degrees around the axis 3 and 5 spacing distribution, and inner diameter of outer cylinder 2 or inner cylinder 4
The present measuring method for calculating the shape of the cylindrical surface from the distribution of the outer diameter can also be carried out by the above-described measuring device.

The above-mentioned measuring method is practical in that the measurement result of the correct shape can be obtained when the axis of the cylinder is aligned with the vertical direction, and can sufficiently exert the effect on the cylindrical surface shape measurement.

Next, FIG. 7 will be described. In the description so far, the case where the cylinder to be measured is in the vertical plane has been described. By the way, in contrast to the above, the shape may change when the cylinder is rotated except when it is vertical, and in this respect, accurate measurement may not be performed as expected, so take measures against this. Will be useful.

Specifically, when the measurement surface is in the horizontal plane, the measurement is performed in a form including deformation due to gravity, and when considering this, it is difficult to say that the shape is accurately measured. . In particular, in the case of a material that is easily deformed, the measurement result is more likely to be affected by the gravity deformation than that of a material that is not easily deformed. This is also the case when facing in any direction other than horizontal vertical. There is no guarantee that the shape of the measured cylindrical surface will not change when the measured cylindrical surface is rotated 180 degrees when the measured cylindrical surface is oriented in a direction other than the vertical direction. Therefore, another object of the present invention described below is to provide a method capable of performing accurate measurement even when the surface to be measured is in a plane other than the vertical plane.

FIG. 7 is a diagram showing an example of a cylindrical surface measuring device when the cylinder is installed horizontally. This is intended to realize the above-mentioned purpose, with the following points in mind. That is, as described above, when the axis of the cylinder is not vertical, rotating the cylinder makes it difficult to perform accurate measurement if the shape changes, but for the inner cylinder, both ends are known as V blocks or edges. Since it is considered that the shape of the central part does not change when supported by the supporting device of this example, this example is used, and the shape of the inner surface of the cylinder is measured by the method shown in FIG. can do. In addition,
In this example, the cylinder is placed horizontally, but the same measurement can be performed when the cylinder is placed other than horizontal.

The main parts will be described below. The contents of measurement, procedures and the like according to this example are as follows. In FIG. 7,
The cylinder 4 whose shape is known by the above-mentioned method is fixed to the base 14 via the supporting devices 15 and 16 fixed to the base 14. Further, here, the outer cylinder 2 having the measured cylindrical surface 3 (the shape of the outer surface does not need to be circular) is movable in the left-right direction (X direction) in the figure, and thus in the horizontal direction. It is fixed to.

An interferometer for interval measurement 1 (main body) shown in FIG. 4 or FIG. 5, which is an interval measuring device, is fixed to a holding arm 10, and the holding arm 10 is fixed to a rotating body 11. . The bearing 17 of the rotating body 11 is fixed to the movable table 13. The movable table 13 is slidable in the X-axis direction by a known method. The reflecting mirror 18 is a reflecting mirror having a reflecting surface 19 of a known shape and placed in parallel with the X axis, and is fixed to the base 14 via an appropriate fixing member (not shown).

By the interferometer 20 fixed to the outer cylinder 2,
When the movable table 13 moves, its movement z in the Z direction (vertical direction in the figure) is measured. Although not shown, the movement y of the movable table 13 in the Y direction is similarly measured by an interferometer.
Further, regarding the rotating body 11, in the one shown in FIG. 6, the inner hole of the rotating body 11 only needs to pass the light beam from the laser, so that the diameter thereof is sufficient.
In the apparatus in the case of FIG. 7, the rotating body 11 has a sufficiently large inner hole so that the cylinder 4 (inner cylinder) can pass therethrough, as shown in the drawing. A base 21 is also fixed to the base 14 of the apparatus, and the laser 6 installed on the fixed base 21 is fixed.
A light beam from (for example, the above-mentioned two-frequency laser or the like) is rotated by another rotating body 22 that is interlocked with the rotating body 11.
The reflecting mirrors 7 and 8 attached to the are used to guide the interferometer 1 for distance measurement. In the figure, reference numeral 23 denotes a bearing of the rotating body 22.

In the present apparatus, measurement is performed using the central portion of the cylinder 4, and the position x of the movable base 13, the movement z in the Z direction, the movement y in the Y direction, and the measurement value of the interferometer 1 for measuring the distance are measured. Thus, the shape of the inner surface 3 of the outer cylinder can be measured. When the inner surface shape of the outer cylinder 2 is known in this way, the outer surface shape of the cylinder can be measured with reference to this. That is, instead of a cylinder of known shape, a cylinder to be measured may be installed and the measurement may be performed in the same procedure.

This embodiment utilizes the fact that when the cylinder is held vertically, the shape does not change at the center when the cylinder is held horizontally at both ends.
It goes without saying that it is not essential to measure the movement of the outer cylinder in the Y and Z directions with respect to the reference plane, and other measuring means can be used.

Next, another embodiment of the distance measurement will be described with reference to FIG. In the embodiments described so far, the interferometer shown in FIG. 4 or 5 is used for measuring the distance between the cylindrical surfaces, but other distance measuring methods can be used.

FIG. 8 shows one of them, which is an example in which the cantilevers 118 and 119 of the atomic force microscope are combined with the interferometer 1 for measuring the interval shown in FIG. 5, for example, and in this case, the outer cylinder and the inner cylinder. The distance between the two cylindrical surfaces of the cantilever 118, 119 is measured by obtaining the distance between the back surfaces of the tips 120, 121 of each end of the cantilevers 118, 119 by the interferometer 1.

In this example, each cantilever 118,
The back surface of the chips 120 and 121 in 119 is a mirror surface. Tip of one tip 120 and cylindrical surface 3
And the distance between the tip of the other tip 121 and the cylindrical surface 5 are usually parallel to the back surface of the tip.
2, 123, and the position sensor 12 detects the position of the reflected light at a position away from the mirrors 124, 125 through the reflecting mirrors 124, 125.
6, 127 and position sensors 126 and 127 for detecting the position of the reflected light in this way and each chip 1
Actuator 12 for changing the position of 20, 121
With a combination of 8,129, the interatomic force is controlled to be constant, so that it is kept constant. The interferometer 1 is used to measure the positional change of the back surface of the chip when the distance between the cylindrical surface and the tip of the chip is constant.

In this embodiment in which the cantilevers 118 and 119 of the atomic force microscope and the interferometer 1 for measuring the distance are combined as described above, the lateral resolution is the respective cantilevers 118 and 119.
Since it is determined by the size of the chips 120 and 121 at the end of the, it can be set to a nanometer or less. Compared with the embodiment shown in FIG. 5, it is possible to easily obtain a high lateral resolution that cannot be realized by using only the interferometer 1 itself, and a more highly accurate result can be obtained.

The position change of the back surface of the chip when the distance between the cylindrical surface and the tip of the chip becomes constant as described above can be measured by using the interferometer 1 combined as shown in FIG. It can also be measured by other means such as a method of detecting a change. Therefore, the use of such means is not hindered. The present invention can also be implemented using the above-described method of measuring the distance.

[0061]

According to the method of the present invention, it is possible to measure from three measured values of the surface distance when the outer cylinder and the inner member are combined by the distance measuring device using the distance measuring interferometer or the electric micrometer. By calculating the surface shape, it is possible to accurately measure the cylindrical surface shape and the like. Any of the three types of distributions obtained according to this method for shape measurement can be obtained by measuring the distance between the surfaces, which enables accurate measurement with the fewest number of measurements, and can be performed easily. It is practical and requires less time.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and is a diagram for explaining measurement of a surface distance between an outer cylinder and an inner cylinder.

FIG. 2 is also a diagram for explaining the diameter measurement of the outer cylinder.

FIG. 3 is applicable in a method according to another embodiment of the present invention,
It is a figure which shows an example at the time of measuring the diameter of an inner cylinder.

FIG. 4 is a diagram showing an example of a configuration of an interval measuring interferometer applicable as an interval measuring device.

FIG. 5 is a diagram similarly showing another example of the configuration of the interferometer for measuring the interval.

FIG. 6 is a general view of the measuring device, showing an example of a cylindrical surface measuring device installed in the vertical direction.

FIG. 7 is a diagram showing an example of a cylindrical surface measuring device installed in the horizontal direction similarly.

FIG. 8 is a diagram for explaining another example of interval measurement.

[Explanation of symbols]

 1 Interval measuring device (interferometer for interval measurement) 2 Outer cylinder 3 Inner surface of outer cylinder 4 Inner cylinder 5 Outer surface of inner cylinder 6 Laser 7, 8, 9 Reflector 10 Holding arm of interferometer for distance measurement 11 Rotating body 12 Strut 13 Moving Base 14 Bases 15 and 16 Supporting Device 17 Bearing 18 Reflecting Mirror 19 Reflecting Surface 20 Interferometer 21 Unit 22 Rotating Body 101 Polarizing Prism 102, 103 ¼ Wave Plate 104 Polarizing Plate 105 Photosensitive Element 106, 107, 108 Lens 118 , 119 Atomic force microscope cantilever 120, 121 Cantilever tip 122, 123 Incident parallel luminous flux 124, 125 Reflector 126, 127 Position sensor

Claims (1)

[Claims] 1. A space distribution between both outer circumferential surfaces of an outer cylinder and an inner member having an outer circumferential surface having a diameter smaller than that of the inner circumferential surface of the outer cylinder, when the two members are coaxially arranged. A shape of the circumferential surface is calculated from a space distribution of both circumferential surfaces in a state where the cylinder or the inner member is rotated about the axis by 180 degrees, and a distribution of the inner diameter of the outer cylinder or the outer diameter of the inner member. Measuring method of circumferential surface shape.