JP2000136918A - Parallelism inspection apparatus for micrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a parallelism inspection apparatus for micrometer, which abolishes an inspection process performed by handwork and which can automate the inspection process of the parallelism of a micrometer. SOLUTION: In this parallelism inspection apparatus, an elastic body 3 is interposed and mounted between a measuring block 2 and a beam-splitter block 1. Then, the measuring block 2 and the beam-splitter block 1 are brought into close contact with the anvil end face and the spindle end face of a micrometer. Then, a reflecting face which is uses as a measuring face 2b is formed on the measuring block 2. Then, a semitransparent face which is used as a reference face 1b is formed on the beam-splitter block 1. A laser beam is made incident on the beam-splitter block 1. Interference fringes by reflected light from the measuring face 2b and by reflected light from the reference face 1b are detected. The parallelism of the anvil end face to the spindle end face is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micrometer inspection apparatus, and more particularly to an apparatus for inspecting the parallelism between an anvil and a spindle.

[0002]

2. Description of the Related Art As is well known, in a micrometer which is a precision measuring instrument, an object to be measured is sandwiched between an anvil serving as a reference for measurement and a spindle which is precisely moved with respect to the anvil. Measure the dimensions of Therefore, in the micrometer having such a structure, if the spindle is inclined with respect to the anvil, the spindle surface is inclined with respect to the anvil surface which is the contact surface with the object to be measured, which causes a measurement error. .

For this reason, in the conventional inspection process of a micrometer, as shown in FIG. 3, an optical parallel made of optical glass is interposed between an anvil and a spindle of the micrometer, and optical interference occurs in the directions of arrows A and B. By observing the fringes, the parallelism between the anvil surface and the spindle surface is checked. That is, when an optical parallel having two optically parallel surfaces is interposed between the anvil and the spindle, interference fringes corresponding to these parallel surfaces on the spindle side and the anvil side as shown in the attached drawings are observed. By observing these interference fringes, the parallelism of the spindle with respect to the anvil can be known.

[0004]

However, in the conventional parallelism inspection method using the optical parallel as described above, since the optical parallel with the easily damaged optical glass is used, the inspection is performed due to the premature damage of the precious parallel surface. There was a problem that the cost was expensive and a manual inspection method with large individual differences was required.

An object of the present invention is to eliminate the manual inspection process and to automate the parallelism inspection process in view of the above-described problems of the conventional micrometer parallelism inspection device. The aim is to obtain a micrometer parallelism inspection device that can be used.

[0006]

In order to achieve this object, the present invention provides an elastic member interposed between a measurement block and a beam splitter block, and the measurement block and the spindle are provided on the end faces of an anvil and a spindle of a micrometer. By bringing the beam splitter block into close contact with each other, forming a reflection surface serving as a measurement surface on the measurement block and forming a semi-transmission surface serving as a reference surface on the beam splitter block, and causing a laser beam to enter the beam splitter block. The present invention proposes a parallelism inspection apparatus for a micrometer that detects interference fringes of light reflected from the measurement surface and light reflected from the reference surface, and measures parallelism between the anvil end surface and the spindle end surface.

In the following description of a preferred embodiment of the present invention, 1) an external contact surface of the measuring block which is in contact with one of the anvil end surface and the spindle end surface is parallel to the measuring surface; The external contact surface of the beam splitter block that is in contact with the other of the anvil end surface and the spindle end surface is parallel to the reference surface.2) The elastic body is a metal bellows that can be elastically deformed. A structure in which the external contact surfaces of the measurement block and the beam splitter block are elastically contacted with the corresponding anvil end surface and the spindle end surface, respectively.3) the elastic body can be elastically deformed by a fluid pressure supplied and discharged into an internal space, The external contact surfaces of the measurement block and the beam splitter block are brought into contact with each other at the same fluid pressure supplied. 4) The elastic body can be elastically deformed by the fluid pressure supplied / discharged to / from the internal space, and when the fluid pressure is discharged, the measuring block and the measuring block A structure in which the external contact surface of the beam splitter block is separated from the corresponding anvil end surface and the spindle end surface will be described.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 shows a structural part of a parallelism inspection apparatus according to the present invention, which is used between an anvil A and a spindle S of a micrometer.

That is, this parallelism inspection apparatus comprises a rectangular parallelepiped beam splitter block 1 made of optical glass and a measurement block 2 made of metal which does not expand or contract due to a temperature change. This beam splitter block 1 is an anvil of the anvil A. It has an external contact surface 1a that can contact the end surface,
On the opposite side of the external contact surface 1a, a reference surface 1b, which is a light transmitting surface, is formed while maintaining a parallel relationship with the external contact surface 1a. The measuring block 2 has an external contact surface 2a which can contact the spindle end surface of the spindle S. On the opposite side of the external contact surface 2a, a measuring surface 2b which is a light reflecting surface is provided with respect to the external contact surface 2a. It is formed keeping the parallel relationship. Therefore, when the external contact surface 1a of the beam splitter block 1 is brought into close contact with the anvil end surface of the anvil A, and the external contact surface 2a of the measurement block 2 is brought into close contact with the spindle end surface of the spindle S, the reference surface 1b and the measurement surface 2b become The angle relationship between the anvil end face and the spindle end face is slightly similar to that between the anvil end face and the spindle end face.

The reference surface 1b and the measurement surface 2
b, between the opposite ends 1c and 2c of the cylindrical shape of the beam splitter block 1 and the measurement block 2 corresponding to b, both ends of an elastic body as shown in the case of the metal bellows 3 are fixed in an airtight manner.
Fluid pressure such as air pressure can be supplied to and discharged from the internal space 4 of the metal bellows 3 which is a closed space. That is, when vacuum pressure is applied to the internal space 4 of the metal bellows 3, the entire metal bellows 3 is reduced, so that the parallelism inspection device can be removed from between the anvil A and the spindle S.
Is released to the atmospheric pressure, the beam splitter block 1 and the measurement block 2 can be pressed against the anvil end face and the spindle end face with a substantially constant pressure due to the elasticity of the metal bellows 3 itself.

Of course, in supplying and discharging fluid pressure to and from the internal space 4 of the metal bellows 3, the beam splitter block 1 and the measuring block 2 are removed from the anvil A and the spindle S by releasing the internal space 4 to the atmosphere. An embodiment may be adopted in which the metal bellows 3 is extended by supplying a fluid pressure to the internal space 4 so that the beam splitter block 1 and the measurement block 2 are brought into close contact with the anvil A and the spindle S, respectively.

An optical system housing 7 having a polarizing beam splitter 5 and a λ / 4 wave plate 6 built therein is fixed above the beam splitter block 1, and an end of the optical system housing 7 is shown in FIG. An optical fiber 9 guided from a laser light source 8 is connected. That is, the laser light emitted from the optical fiber 9 is converted into a parallel beam by the lens 10 and is incident on the above-described beam splitter block 1 via the polarization beam splitter 5 and the λ / 4 wavelength plate 6, and is transmitted from the measurement surface 2b. Interference between the reflected light and the reflected light from the reference surface 1b occurs.

The interference signal is rotated by 90 degrees with respect to the incident laser light by passing through the λ / 4 wavelength plate 6, reflected by the polarization beam splitter 5, and coupled to the photosensitive surface of the CCD camera 12 by the lens 11. The image is observed and measured by a monitor (not shown) that displays an interference fringe image from the CCD camera 12.

The light reflected from the measurement surface 2b and the reference surface 1
If interference fringes with high contrast cannot be obtained due to the difference in intensity from the reflected light from b, a coating layer for controlling the reflectance (transmittance) may be formed on the surface of the measurement surface 2b and / or the reference surface 1b. .

Since the parallelism inspection apparatus for a micrometer according to the illustrated embodiment has the above-described configuration, the measurement surface is sandwiched between the beam splitter block 1 and the measurement block 2 between the micrometer anvil A and the spindle S. 2b
By observing the interference fringes caused by the reflected light from the reference surface 1b and the light reflected from the reference surface 1b, the parallelism between the anvil end face and the spindle end face can be easily known. In particular, in a configuration in which fluid pressure is supplied to and discharged from the internal space 4 of the metal bellows 3 which is an elastic body, not only a stable measurement pressure can be obtained for the anvil end face and the spindle end face, but also the parallelism inspection by supplying and discharging fluid pressure. Since the device can be easily removed from between the anvil A and the spindle S, there is little risk of damaging the valuable external contact surfaces of the beam splitter block 1 and the measurement block 2, and even if it is damaged, the reflection surface is not damaged. Since there is no interference fringe image, the inspection process can be automated because the image does not deteriorate.

In the above description of the embodiment, an example is described in which the external contact surface of the measurement block 2 is brought into contact with the spindle S and the external contact surface of the beam splitter block 1 is brought into contact with the anvil A. To the anvil A side, and the beam splitter block 1 to the spindle S
It is needless to point out again that the same operation and effect can be obtained even when the contact is made to the side.

[0017]

As is apparent from the above description, according to the micrometer parallelism inspection apparatus of the present invention, the micrometer parallelism inspection process conventionally performed manually can be automated. Thus, it is possible to maintain the reliability of test results that require skill and differ from individual to individual.

[Brief description of the drawings]

FIG. 1 is a sectional view of a micrometer parallelism inspection apparatus according to the present invention.

FIG. 2 is a system diagram of an optical system of the parallelism inspection apparatus.

FIG. 3 is an explanatory diagram of a parallelism inspection method using a conventional optical parallel.

[Explanation of symbols]

 A Anvil S Spindle 1 Beam splitter block 1a External contact surface 1b Reference surface 2 Measurement block 2a External contact surface 2b Measurement surface 3 Metal bellows 4 Internal space 5 Polarization beam splitter 6 λ / 4 wavelength plate 7 Optical housing 8 Laser light source 12 CCD camera

Claims (5)

[Claims] 1. An elastic body is interposed between a measurement block and a beam splitter block, and the measurement block and the beam splitter block are brought into close contact with an anvil end face and a spindle end face of a micrometer to form a reflection surface serving as a measurement surface. A semi-transmissive surface, which is formed on the measurement block and serves as a reference surface, is formed on the beam splitter block. A parallelism inspection apparatus for a micrometer, which detects interference fringes and measures the parallelism between the end face of the anvil and the end face of the spindle. 2. The beam splitter, wherein an external contact surface of the measurement block that is in contact with one of the anvil end surface and the spindle end surface is parallel to the measurement surface, and is in contact with the other of the anvil end surface and the spindle end surface. 2. The micrometer parallelism inspection apparatus according to claim 1, wherein an external contact surface of the block is parallel to the reference surface. 3. The elastic body is a metal bellows that can be elastically deformed, and the elastic contact of the metal bellows causes the external contact surfaces of the measuring block and the beam splitter block to elastically contact the corresponding anvil end surface and the spindle end surface, respectively. The parallelism inspection apparatus for a micrometer according to claim 1 or 2, wherein: 4. The elastic body can be elastically deformed by the fluid pressure supplied to and discharged from the internal space, and the anvil end face and the external contact surface of the measurement block and the beam splitter block corresponding to the supplied fluid pressure. 3. The micrometer parallelism inspection apparatus according to claim 1, wherein the spindle end faces are elastically contacted with each other. 5. The anvil end face corresponding to an external contact surface of the measurement block and the beam splitter block when the elastic body is elastically deformed by a fluid pressure supplied to and discharged from an internal space. 3. The micrometer parallelism inspection apparatus according to claim 1, wherein the apparatus is separated from the spindle end face.