JPH083410B2 - Three-dimensional coordinate measuring machine - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a three-dimensional coordinate measuring machine for three-dimensionally measuring the shape of a sample.

(Background of the Invention) In the conventional three-dimensional coordinate measuring machine, the feeler sphere of the probe that specifies the measurement point of the sample has a structure that is far away from the reference scale for measuring the amount of movement of the probe. Inevitable Abbe error caused by
This causes a decrease in measurement accuracy. In order to improve the measurement accuracy, it is necessary to improve the accuracy of the guide member that serves as a reference for moving the probe, which has a drawback that the cost is greatly increased.

(Object of the Invention) An object of the present invention is to solve such a drawback and to obtain a three-dimensional coordinate measuring machine capable of highly accurate measurement.

(Summary of the Invention) The invention described in the section of the first invention of the present application provides a substrate (10a), an intermediate plate (10b) (1) that moves along the Y-axis on the substrate, and an X-axis on the intermediate plate. A cross movement stage (10) having an upper plate (10c) that moves along the cross movement stage and the cross movement stage (Z).
A three-dimensional coordinate measuring machine comprising a base (11) movably mounted along an axis and a probe (13) for detecting an object to be measured, comprising a light source (1), the X-axis and the Y-axis. First and second reflecting mirrors (5, 50) fixed to the upper plate of the cross movement stage and having reflection surfaces orthogonal to each other, and the cross movement stage having reflection surfaces orthogonal to the Z axis A third reflecting mirror (500) fixed to the bottom surface of the substrate, and the light from the light source is divided into three light beams parallel to the X-axis, Y-axis, and Z-axis, and the divided three light beams are Optical members (2-4, which make the first, second, and third reflecting mirrors vertically incident respectively)
8, 9, 40, 400) and a lightwave interferometer
The probe is fixedly provided on the base, and the optical member is arranged such that extension lines of the divided three light beams intersect at the center of a feeler sphere of the probe.

The invention described in the second invention of the present application provides a substrate (10a), an intermediate plate (10b) that moves on the substrate along the Y axis, and an upper plate (10c that moves on the intermediate plate along the X axis. ) And a workpiece placing plate (10d) movably provided along the Z-axis with respect to the upper plate, and a probe (13) for detecting an object to be measured. In the three-dimensional coordinate measuring machine, a light source (1) and first and second reflecting mirrors (5) having reflecting surfaces orthogonal to the X axis and the Y axis and fixed to the upper plate of the cross movement stage. , 50), a third reflecting mirror (500) having a reflecting surface orthogonal to the Z-axis and fixed to the bottom surface of the work mounting table, and the light from the light source to the X-axis, Y-axis and Z-axis. The light flux is divided into three light fluxes each parallel to the axis, and the divided three light fluxes are formed on the first and second reflecting mirrors, the substrate, the middle plate and the upper plate. The third optical member to be incident perpendicularly, respectively to the reflecting mirror through the through-hole (2
〜4,8,9,40,400), and the probe is fixedly provided to the substrate,
The optical member is arranged so that extension lines of the divided three light beams intersect at the center of the feeler sphere of the probe.

(Embodiment) FIGS. 1 to 4 show a first embodiment of the present invention.
1 is a plan view, FIG. 2 is a sectional view taken along the line AA ′ of FIG. 1, FIG. 3 is a sectional view taken along the line BB ′ of FIG. 1, and FIG. FIG. 7 is a cross-sectional view taken along the arrow C ′.

The light emitted from the laser light source 1 along the X axis is split by the first beam splitter 2 into transmitted light along the X axis and reflected light along the Y axis. The transmitted light of the first beam splitter 2 is split into transmitted light along the X axis and reflected light along the Z axis by the second beam splitter 3, as shown in FIG. The reflected light of the second beam splitter 3 is split by the third beam splitter 4 into reflected light along the X axis and transmitted light along the Z axis. The light reflected by the third beam splitter 4 is vertically incident on the first reflecting mirror 5 arranged on the cross movement stage 10 in the Y direction. This incident light is reflected by the reflecting mirror 5, then passes through the third beam splitter 4, and enters the detector 6. On the other hand, the second beam splitter 3 is reflected and the third beam splitter 4
After passing through the corner cube 7, the light is reflected and then enters the third beam splitter 4, and the reflected light there enters the detector 6. As a result, the movement of the interference fringe between the reflected light from the first reflecting mirror 5 and the reflected light from the corner cube 7 can be detected by the detector 6, and the movement of the interference fringe causes the first reflecting mirror 5 to move. Can be measured in the X direction.

That is, the laser light source 1, the first beam splitter 2, the second beam splitter 3, the third beam splitter 4, the first reflecting mirror 5, the detector 6, the corner cube 7
The light wave interferometer length measuring device for measuring the so-called X-direction movement amount is constituted by.

On the other hand, the light reflected by the first beam splitter 2 in the direction along the Y-axis is reflected by the plane reflecting mirror 8 in the direction along the X-axis and then is reflected by the fourth beam splitter 4 as shown in FIG. As shown in the figure, the light enters the plane reflecting mirror 9 and is reflected in the direction along the Z axis. This reflected light enters the fourth beam splitter 40 and is split into reflected light along the Y axis and transmitted light along the Z axis. The reflected light of the fourth beam splitter 40 is vertically incident on the second reflecting mirror 50 arranged on the cross movement stage 10 in the X direction. This incident light is reflected by the reflecting mirror 50, then passes through the fourth beam splitter 40, and enters the detector 60. On the other hand, the light reflected by the first beam splitter 2 and transmitted through the fourth beam splitter 40 enters the corner cube 70, is then reflected and enters the fourth beam splitter 40, and the reflected light there is a detector. Incident on 60. As a result, the movement of the interference fringe between the reflected light from the second reflecting mirror 50 and the reflected light from the corner cube 70 can be detected by the detector 60, and the movement of the interference fringe causes the second reflecting mirror 50 to move. The amount of movement in the Y direction can be measured.

That is, the laser light source 1, the first beam splitter 2, the fourth beam splitter 40, the second reflecting mirror 50, the detector 60, and the corner cube 70 are used to measure a so-called Y-direction movement amount. Is configured.

Then, as shown in FIG. 1, the extension line of the optical axis of the light reflected by the third beam splitter 4 toward the first reflecting mirror 5 and the second line by reflecting the fourth beam splitter 40. The extension line of the optical axis of the light that goes to the reflecting mirror 50 of the
10 Each optical member is arranged so as to intersect at one point P above.

Further, the light transmitted through the second beam splitter 3 enters the beam splitter 400 and is reflected by the Z axis along with the reflected light.
And the transmitted light along the axis. The light reflected by the fifth beam splitter 400 is a third reflecting mirror 500 fixedly mounted on the lower surface of the cross movement stage 10 movably arranged in the Z-axis direction.
Incident on the fifth beam splitter.
It passes through 400 and enters the detector 600. On the other hand, the light that has passed through the second beam splitter 3 and the fifth beam splitter 400 enters the corner cube 700 and then is reflected and enters the fifth beam splitter 400, and the reflected light there is detected by the detector 600. Incident on. As a result, the movement of the interference fringe between the reflected light from the third reflecting mirror 500 and the reflected light from the corner cube 700 can be detected by the detector 600, and the movement of the interference fringe causes the third reflecting mirror 500 to move. Can be measured in the Z direction.

Then, as shown in FIGS. 2 and 3, the extension line of the optical axis of the light reflected by the fifth beam splitter 400 and directed to the third reflecting mirror 500 intersects at the above-mentioned point P. Each optical member is arranged.

Then, as described above, the laser light source 1, the first beam splitter 2, the second beam splitter 3, the fifth beam splitter 400, the third reflecting mirror 500, the detector 600, and the corner cube 700 allow the so-called Z direction. An optical wave interferometer for measuring the amount of movement is configured.

The cross movement stage 10 has a well-known structure
10a, an intermediate plate 10b that moves on the base 10a along the Y axis,
It has an upper plate 10c which moves on the middle plate 10b along the X axis.
The cross movement stage 10 has a base 11 having a well-known structure.
On the other hand, it moves along the Z axis. In the case of this example, as shown in FIGS. 2 and 3, an opening is formed near the central portion of the base 11, and the fifth beam splitter 40
The light reflected from 0 is configured to enter the third reflecting mirror 500 fixedly provided on the lower surface of the substrate 10a of the cross movement stage 10 through this opening.

A touch trigger probe 13 is arranged so that the center point of the feeler ball 12 substantially coincides with a point P above the upper plate 10c of the cross movement stage 10. This probe 13 has the center of the feeler ball 12 at a point P. As always, the fixed side, namely the base 11
On the side.

Due to this structure, the upper plate of the cross movement stage 10
When the object to be measured (cylindrical) 14 is placed on 10c and the inner diameter thereof is to be measured, the cross movement stage 10 is set to the X-axis, Y-axis.
The feeler sphere 12 moves inside the cylinder 14 by moving in the axial and Z-axis directions.
After inserting, the cross movement stage 10 may be moved in the X-axis direction or the Y-axis direction. That is, in FIG. 2, the upper plate 10c of the cross movement stage 10 is moved in the X-axis and Y-axis directions, the feeler balls 12 are brought into contact with three points having different inner circumferences, and the touch obtained from the touch trigger probe 13 is obtained. If the values of the detectors 6, 60, 600 (counter values of the counters) are loaded in synchronism with the signal, the coordinates of the three contact points can be obtained (at this time, the diameter of the feeler ball 12 is not corrected). The diameter of the inner circumference can be calculated.

In this way, the center of the feeler sphere 12, that is, the coordinate value of the point P can be measured by ignoring or correcting the diameter of the feeler sphere 12. The extension lines of the optical axes of the three sets of interferometers are orthogonal to each other at the center P of the feeler sphere 12 as a length measurement line, so that X-axis, Y-axis, and Z-axis always satisfy the Abbe principle for high-precision measurement. The vertical movement mechanism of the cross movement stage 10 and the movement accuracy of the cross movement stage 10 are slightly inferior to the measurement accuracy.
There is an advantage. The orthogonal accuracy is determined to be within the required error range.

In the above embodiment, the light wave interferometer was used as the length measuring device. However, the length measuring device has another structure, for example, the pinole type length measuring device as shown in the second embodiment of FIGS. 5 to 6. Can be used.

5 is a plan view, FIG. 6 is a sectional view taken along the line AA ′ of FIG. 5, and FIG. 7 is a sectional view taken along the line BB ′ of FIG.

In Fig. 5, the spindle shaft of the pinole type length measuring device 15
The tip of 15a is in contact with the side surface of the reference member 16 extending in the Y-axis direction. The spindle shaft 15a of the pinole type length measuring device 15 is constantly urged in a direction projecting from the case by a spring (not shown) built in the case, and is fixed to the shaft 15a so that its central axis and the scale surface are aligned with each other. By reading the scale on the scale, for example photoelectrically, the spindle axis
The amount of retreat of 15a can be measured. Spindle axis 1
Since 5a is always biased in a direction projecting from the case, even if the upper plate 10c of the cross movement stage moves in the X-axis direction, its tip always contacts the reference member 16. The pinole type length measuring device 15 is for measuring the moving amount in the X axis direction, and the pinol type measuring device 17 is for measuring the moving amount in the Y axis direction, and the moving amount in the Z axis direction. A pinole type length measuring device 19 is provided for measurement. The pinole type length measuring device 17 also has a spindle shaft 17a, and its tip is X-shaped.
The tip end of the spindle shaft 19a of the pinole type length measuring device 19 is in contact with the side surface of the reference member 18 extending in the axial direction, and a through hole formed in the central portion of the cross movement stage 10 in the Z-axis direction,
Work rest 1 provided on the upper plate 10c so as to be movable in the Z direction
It is in contact with a reference member 21 fixed to the bottom surface of 0d.

The extension line of the central axis of the spindle shafts 15a, 17a, 19a is a length measurement line, which is orthogonal to a point P above the work placement table 10d, and the touch trigger probe 13 is aligned there with the center of the feeler ball 12. Are fixedly provided on the substrate 10a.

Of course, the pinole type length measuring device 19
Since the central plate 10b that moves in the axial direction and the upper plate 10c that moves in the Z-axis direction pass through the central part of the intermediate plate 10b, the through hole formed in the central part of the cross movement stage 10 in the Z-axis direction is , Middle plate
The size is set to allow sufficient movement of the upper plate 10b and the upper plate 10c.

According to the second embodiment having such a structure, the reference member 16,
Since 18 does not move in the direction along the Z axis, the X axis or Y
The size is enough to cover the movement in the direction along the axis,
Easy to make.

Also, since the height of the reference members 16 and 18 can be held low, the tips of the reference members 16 and 18 greatly protrude above the measurement point of the low-height measurement object, which hinders the confirmation of the measurement point. There is no such problem.

The other structure of the second embodiment is similar to that of the first embodiment, and the operation can be performed in the same manner.

If the stage structure of the second embodiment is replaced with the stage of the first embodiment, the first reflecting mirror 5 and the second reflecting mirror 50
The size of can be made small like the reference members 16 and 18 in the second embodiment, and not only the manufacture is easy, but
Since the height can be lowered, the measurement points can be easily confirmed.

(Effect of the Invention) As described above, according to the present invention, since measurement is always performed in a state in which the Abbe's principle is satisfied in all three axial directions, there is an advantage that high-accuracy measurement can be performed, and a cross stage or There is an effect that the movement accuracy of the vertical movement device can be made rough and these portions can be configured at low cost.

Moreover, since the light source of the interferometer is shared in the X, Y, and Z axis directions by utilizing the fact that the optical axes in the X, Y, and Z axis directions do not move, the structure of the entire measuring machine can be simplified and downsized. There is an effect.

Further, in the second invention of the present application, the sizes of the first and second reflecting mirrors can be reduced, and the production is facilitated, so that there is an advantage that the production can be performed at low cost.

[Brief description of drawings]

1 is a plan view of a first embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA 'in FIG. 1, and FIG. 3 is a sectional view taken along the line BB' in FIG. 4 is a sectional view taken along the line CC 'in FIG. 1, FIG. 5 is a plan view of the second embodiment of the present invention, and FIG. 6 is A- in FIG.
FIG. 7 is a sectional view taken along the line BB 'in FIG. (Description of symbols of main parts) 1 ... Laser light source 2 ... First beam splitter 3 ... Second beam splitter 4 ... Third beam splitter 5 ... First reflecting mirror 50 ... Second Reflector 500 …… Third reflector 6,60,600 …… Detector 7,70,700 …… Corner cube P …… Measuring line intersection 10 …… Crossing stage 12 …… Feeler sphere 13 …… Touch trigger probe 15,17,19 …… Pinol type length measuring device 16,18,21 …… Reference member.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuhiro Shinada Nobuhiro Shinada 471 Nagaodai-cho, Totsuka-ku, Yokohama-shi, Kanagawa Nippon Optical Industry Co., Ltd. Yokohama Works (56) Bibliography 60-35210 (JP, U) Public Sho 51-20908 (JP, B1)

Claims (2)

[Claims] 1. A cross movement stage having a substrate, an intermediate plate that moves on the substrate along the Y axis, and an upper plate that moves on the intermediate plate along the X axis, and the cross movement stage includes the Z axis. In a three-dimensional coordinate measuring machine equipped with a base movably mounted along the probe and a probe for detecting an object to be measured, the cross movement stage is orthogonal to the light source and the X-axis and the Y-axis, respectively. First and second reflecting mirrors having a reflecting surface and fixed to the upper plate of the cross movement stage, and a first and second reflecting mirror having a reflecting surface orthogonal to the Z axis and fixed to the bottom surface of the substrate of the cross movement stage. The reflecting mirror of No. 3 and the light from the light source
An optical wave interferometer with an optical member that splits into three light fluxes parallel to the axis, the Y-axis and the Z-axis, and makes the split light fluxes vertically enter the first, second and third reflecting mirrors, respectively. The probe is fixedly provided to the base, and the optical member is arranged such that extension lines of the divided three light beams intersect at the center of a feeler sphere of the probe. 3D coordinate measuring machine characterized by. 2. A substrate, an intermediate plate that moves on the substrate along the Y axis, an upper plate that moves on the intermediate plate along the X axis, and a movable plate along the Z axis with respect to the upper plate. In a three-dimensional coordinate measuring machine comprising a cross movement stage having a work mounting table provided and a probe for detecting an object to be measured, the cross movement stage is orthogonal to the light source and the X axis and the Y axis. First and second reflecting mirrors having reflecting surfaces fixed to the upper plate of the cross movement stage, and third reflecting mirrors having reflecting surfaces orthogonal to the Z axis and fixed to the bottom surface of the work mounting table. And the light from the light source is divided into three luminous fluxes parallel to the X-axis, Y-axis and Z-axis, respectively.
An optical interferometer length measuring instrument comprising: the first and second reflecting mirrors; and an optical member for vertically entering the third reflecting mirror through through holes formed in the substrate, the middle plate and the upper plate. The probe is fixedly provided on the substrate, and the optical member is arranged so that extension lines of the divided three light beams intersect at a center of a feeler sphere of the probe. 3D coordinate measuring machine.