JPH06103169B2 - Non-contact shape measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a non-contact shape measuring device for measuring the outer shape of a mirror-finished object, for example.

[Conventional technology]

Conventionally, in this type of non-contact shape measuring device, an interference mechanism and an auto-collimation mechanism are independently arranged and function independently.

Therefore, in actual measurement, it is necessary to quantitatively specify the geometrical arrangement of the object to be inspected and each mechanism, for example, the perpendicularity and parallelism between the optical axis and the surface to be measured. It is a thing.

[Problems to be solved by the invention]

However, the geometrical arrangement of the object to be inspected and each mechanism may be time-consuming to operate, and may not be performed accurately, which reduces the measurement accuracy.

Particularly, in the eccentricity measurement, the object to be measured must be measured by rotating the measurement optical axis, and even in this case, it is difficult to quantify the measurement.

The present invention has been made based on such a situation, and the object of the present invention is to perform shape measurement of many items at the same time simply by placing an object to be measured at the time of measurement, and in a short time. Another object is to provide a non-contact shape measuring device that enables measurement.

[Means for solving problems]

In order to achieve such an object, the present invention provides an interference optical system and an autocollimation unit fixedly arranged with respect to the interference optical system so as to have the same optical axis as the optical axis of the interference optical system. An optical system, and an object mounting table arranged between the interference optical system and the auto-collimation optical system, the object mounting table, the object mounting table and the optical axis A stage mechanism capable of moving in a parallel direction, a direction perpendicular to the object mounting base, and a direction perpendicular to the direction; and a rotating mechanism capable of reversing the object mounting base at least 180 °. It is a feature.

[Action]

By doing this, the object to be inspected is placed on the mounting table,
Positioning at a predetermined position by the stage mechanism (with respect to the optical axis), for example, measurement by an interference optical system, and then 180 ° inversion operation by a rotating mechanism enables measurement by an autocollimation optical system.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of a non-contact shape measuring device according to the present invention.

In the figure, an auto-collimation optical system 30 and an interference optical system 40 are relatively arranged via the object 1 to be inspected.

The interference optical system 40 is constructed as follows. There is a laser oscillator 12, and the laser light oscillated and emitted from this laser oscillator 12 is expanded by a converging / diffusing lens 13 and a pinhole, and emitted to a reference lens 17 via a half mirror 15 and a collimator lens 16. It is getting done. The laser light that has passed through the reference lens 17 is focused at an arbitrary point on the object 1 side to be inspected, and when the focus point and the center of curvature of the object 1 to be inspected coincide with each other, The laser light is reflected on the measurement surface of the object 1 to be inspected and returns to the reference lens 17 again.

As a result, the interference fringes are generated by the superposition of the light before reaching the measurement surface and the reflected light, and the interference fringes are generated through the half mirror 15, the imaging lens 18, and the image pickup tube 19 to the TV monitor 20. It is being observed by.

The auto-collimation optical system 30 is constructed as follows. For example, there is a light source 2 composed of a halogen lamp, and the light emitted from this light source 2 passes through a collimator lens 3 and passes through a colored glass filter 4 only light of a specific wavelength. The colored glass filter 4 cuts light having the same wavelength as the wavelength of the laser light, and does not affect the interference optical system 40 side. The light passing through the colored glass filter 4 reaches the collimator lens 8 through the condenser lens 5 and the projection chart 6 to obtain parallel light.
The collimated light is applied to the object 1 having a flat surface, and the reflected light is again incident on the collimator lens 8 and travels backward in the forward path to be bent by the half mirror 7 in the direction of the image pickup tube 10. An image is formed at a position conjugate with. Further, this image is observed on the TV monitor 11 via the image pickup tube 10.

Further, a microscopic collimator lens 9 is arranged between the object 1 to be inspected and the collimator lens 8, and the microscopic collimator lens 9 focuses on the object 1 to be inspected. When it coincides with the center of curvature of the object 1 to be inspected, the focused light is reflected on the surface to be inspected and again imaged on the photographing tube 10 via the micro collimator 9, collimator lens 8 and half mirror 7. .

Next, the holding and moving section on which the object 1 to be inspected is placed will be described. This holding / moving part is a holder 22 for directly mounting the object 1 to be inspected, a reversing mechanism 23 provided under the holder 22,
Further, it is composed of a stage mechanism 24 provided below the reversing mechanism 23. On the upper surface of the holder 22, a V-groove for placing the object 1 to be inspected is formed, and this V-groove is parallel to the optical axis common to the auto-collimation optical system 30 and the interference optical system 40. ing. Further, on the measuring surface of the holder 22, two parallel flat plates 21 are provided so as to be orthogonal to the V groove and parallel to each other. Further the holder
The reversing mechanism 23 is capable of reversing 180 degrees about the axis perpendicular to the optical axis as a central axis. Also,
The stage mechanism 24 can move in three axis directions when one axis parallel to the optical axis is one axis of rectangular coordinates. The movement of each axis is performed by a micrometer head (not shown), and the amount of movement in each of the three axis directions at this time is read by a displacement sensor (not shown), and is displayed.
It is designed to be displayed digitally on the order of 1 to 25 μm. Further, the display 25 can be set to OFF so that the amount of movement from any point can be known.

In the non-contact shape measuring apparatus configured as described above, the interference optical system 40 and the special auto-collimation optical system 30 are arranged so as to be on the same line as possible through the object 1 to be inspected. I am doing it. Also, it moves three-dimensionally with the object to be inspected 1,
A stage mechanism 24 capable of measuring the amount of movement at that time and a reversing mechanism capable of reversing the object 1 to be inspected around an arbitrary axis perpendicular to the optical axis are provided. The object 1 to be inspected is held by a holder installed on the stage. This holder is V
Each surface is in parallel with the measuring optical axis as much as possible so that the outer circumference of the measuring object 1 is parallel to the measuring optical axis when the measuring object 1 is placed. Where interference optics
The parallel between the optical axis of 40 and the special autocollimation optical system 30 and the V groove of the holder is adjusted by another means in advance. Further, the stage mechanism is arranged so that one axis of the Cartesian coordinates is as parallel as possible to the measurement optical axis, and the three axes are independently movable. Further, the two optical systems 30 and 41 change the wavelength of the measurement light in order to eliminate the influence of each other, and the switching operation of the optical systems is unnecessary, and they can be used simultaneously. The optical system to be used is determined by the measurement item, but the surface precision, the radius of curvature, and the thickness of the object to be measured are mainly measured using the interference optical system 40 side.
The special auto-collimation optical system 30 side is used for eccentricity and squareness measurement.

In the actual measurement, simply place the object to be inspected on the holder arbitrarily, and after that, if you operate the stage according to the measurement procedure of each measurement item, you can measure the above measurement item in a short time, It will be possible to save the time and effort of setting the measuring machine.

Further, the micro collimator lens 9 is arranged in the parallel optical path between the auto-collimation optical system 30 and the object to be inspected 1 so as to coexist with parallel rays. Autocollimation optical system
A part of the parallel rays emitted from 30 reaches the parallel plate 31 installed directly on the side surface of the holder. Two flat plates 21 are provided with a rotary shaft perpendicular to the measurement optical axis sandwiched therebetween, and are kept parallel to each other, and are arranged perpendicular to the object mounting surface of the holder. Further, the reversing mechanism 23 is arranged so that the holder including the object 1 to be inspected and the parallel plate 21 can be reversed by 180 ° about the rotation axis. The light emitted from the microscopic collimator lens 9 in the parallel optical path is condensed at an arbitrary point. The stage mechanism 24 is moved so that the measured curvature center of the object 1 to be measured coincides with this converging point. At this time, the reversal light from the surface of the object 1 to be inspected and the reversal light from the parallel plate 21 are backlit again and are bent toward the image pickup tube 10 side by the half mirror 7, and are collected at the image forming point on the image pickup tube. Glow. Here, in advance, determine the measurement optical axis coordinates while observing the monitor with a true sphere, and then
By measuring the amount of deviation of the reflected light of the measured object whose outer shape is measured, the eccentricity can be easily measured without rotating the measured object about the measurement optical axis.

Further, by providing the parallel flat plate, it becomes possible to confirm whether the stage is moving in parallel to the measurement optical axis or whether it is certainly rotated by 180 ° when inverted. For example, if the movement of the stage in the optical axis direction is not parallel to the measurement optical axis, the focal point of the reflected light from the parallel flat plate will deviate as the stage moves. Also, by observing whether the light reflected from each of the parallel plates when inverted is condensed at the same point, it is possible to confirm that the 180 ° inversion has been performed reliably. At the same time, it will be easy.

〔The invention's effect〕

As is apparent from what has been described above, according to the optical contact shape measuring apparatus of the present invention, it is possible to simultaneously measure the shape of multiple items simply by placing the object to be measured on the measuring machine, and to measure in a short time. Like

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a non-contact shape measuring device according to the present invention. 1 ... Object to be inspected, 2 ... Light source, 3 ... Collimator lens, 4 ... Colored glass filter, 5 ... Condensing lens, 6
...... Projection chart, 7 ...... Half mirror, 8 ...... Collimator lens, 9 ...... Micro collimator lens, 10 ...... Image pickup tube, 11 ...... TV monitor, 12 ...... Laser oscillator, 13 ...... Condensing diffusion lens , 14 …… pinhole, 15 …… half mirror,
16 …… collimator lens, 17 …… reference lens, 18 …… imaging lens, 19 …… image pickup tube, 20 …… TV monitor, 21 …… parallel plate, 22 …… holder, 23 …… inversion mechanism, 24… … Stage mechanism, 25 …… Display, 30 …… Auto-collimation optical system, 40 …… Interference optical system.

Claims (1)

[Claims] 1. An interference optical system, an auto-collimation optical system fixedly arranged with respect to the interference optical system so as to have the same optical axis as the optical axis of the interference optical system, and the interference optical system. An object mounting base arranged between the auto-collimation optical system and the object mounting base, wherein the object mounting base is the object mounting base relative to the object mounting base parallel to the optical axis. At least the stage mechanism that can move in a vertical direction and a direction that is perpendicular to each of the directions and the object mounting base.
A non-contact shape measuring device comprising a rotating mechanism capable of reversing 180 °.