JPH09136251A - Device and method for grinding transparent body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide parallel ground surfaces by detecting a parallelism between both end surfaces of a transparent body by the inclined angle of a transmitted light beam relative to the axis of an incident light beam, and grinding both end surfaces of the transparent body until the axes of the incident light beam and transmitted beam are aligned with each other. SOLUTION: A measuring light beam 2a is projected from one end surface 1a, a measuring light beam 2b radiated from the other end surface 1b through transparent body 1 is measured, and a parallelism between the incident side end surface 1a and transparent side end surface 1b is detected by the inclined angle of the transmitted light beam 2b relative the optical axis of the incident light beam 2a. Also the end surface of the transparent body 1 is ground until the axes of the incident light beam 2a and transmitted light beam 2b are aligned with each other so as to grind both end surfaces 1a and 1b in parallel with each other. By this the transparent body 1 can be applied, as a general transparent body, to crystalline or hyalines. For measuring light beam, a laser beam which is high in straight forward traveling is suitable mostly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for polishing opposite end faces of a transparent body in parallel. More specifically, in the case of polishing both ends of a transparent body used for a laser oscillator or the like in parallel, a parallel polishing method capable of easily performing parallel polishing by polishing while optically measuring the parallelism of these polishing surfaces. And equipment.

[0002]

2. Description of the Related Art A laser oscillating device generates coherent light with high excitation energy by repeating resonance of incident light in the device. Both side edges must be processed as flat as possible so that they are parallel to each other and face each other perpendicularly to the light traveling direction. When the parallelism between the both end faces is low, light is repeatedly refracted and diverges, so that the excitation energy cannot be increased.

In order to polish the both end surfaces of the transparent body used for such a laser oscillator or the like in parallel, it is necessary to polish while detecting the parallelism of the both end surfaces, but in the conventional method, the parallelism is determined. However, there is a problem in that the working time is further prolonged because the measurement of the parallelism and the polishing process are separated. That is, conventionally, as an optical method for measuring the inclination of the polishing surface, the angle between the incident light and the reflected light is measured by irradiating the polishing surface of the inspection body installed on the optical axis with light and measuring the reflected light. Is detected or the optical interference fringe is used to measure the inclination of the polished surface. Since these measuring methods utilize the reflected light from the polishing surface, although they have an advantage that they can be applied to a metal material that does not transmit light,
Even when measuring the parallelism of the polishing surfaces on both sides, it has to be measured for each polishing surface on one side, and there is a problem that the measurement takes time. In particular, since polishing is usually performed using a polishing jig in which a large number of polishing bodies are integrally mounted, this inspection method requires that each polishing body be removed from the jig and the polishing surfaces at both ends thereof be measured. After the measurement, the jig is mounted on the jig again and the polishing is repeated, resulting in a significant decrease in work efficiency.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above problems in the conventional parallel polishing method. Instead of the conventional method of using reflected light, transmitted light is used, and transmitted light with respect to the optical axis of incident light is The inclination of the transparent end surface of the transparent body can be easily detected from the inclination, and polishing is performed so that the optical axes of the incident light and the transmitted light coincide with each other so that parallel polished surfaces can be easily obtained. Is. Furthermore, by using a flat plate-shaped jig that can be used for both parallelism measurement and end face polishing, it is possible to continuously perform parallelism measurement and polishing for both end faces while the transparent body is mounted on the jig. To be able to
Even for a large number of transparent bodies, both end surfaces can be polished in parallel in a short time.

[0005]

According to the present invention, the following parallel polishing method is provided. (1) A method of polishing both end faces of a transparent body in parallel, in which measurement light is incident from one end face, transmitted light which is transmitted through the transparent body and radiated from the other end face is measured, and the incident light The parallelism of both end surfaces of the transparent body is detected by the inclination angle of the transmitted light with respect to the optical axis of the light, and the both end surfaces of the transparent body are made parallel by polishing the both end surfaces of the transparent body until the optical axes of the incident light and the transmitted light coincide with each other. A method for polishing a transparent body, which comprises polishing the transparent body. (2) The transparency of the transparent body is attached to the plate-shaped jig, the parallelism of both end surfaces of the transparent body is measured, and a load for eliminating the inclination of the end surface of the transparent body detected by the parallelism is applied to the jig. Both ends of the transparent body are polished in parallel by polishing
The polishing method according to (1). (3) The polishing method according to (2) above, in which a plurality of transparent bodies are attached to a jig in a flat plate shape, and the parallelism of both end faces of each transparent body and the polishing are simultaneously performed on the plurality of transparent bodies.

Further, according to the present invention, the following parallel polishing apparatus is provided. (4) A flat plate-shaped jig that holds a transparent body and is used for both parallelism measurement and polishing of both ends of the transparent body, and means for measuring the parallelism of both end surfaces of the transparent body that penetrates the jig. And a means for polishing the end face of the transparent body which is attached to the jig, the parallel polishing apparatus for both ends of the transparent body. (5) (a) A means for irradiating a transparent body with parallelism measuring means at both ends of the transparent body, and a means for irradiating the transparent body with the measuring light, and the flat jig being perpendicular to the measuring light. A support means for sending the transparent body on the jig to the incident position of the measurement light by moving it while holding it so as to face the screen, and a screen for projecting the measurement light transmitted through the transparent body, (b) polishing means But,
A polishing machine for polishing an end surface of a transparent body that is attached to a flat jig, and a means for applying a load to a predetermined position of the jig.
The polishing apparatus according to (4). (6) The flat jig is provided with a hole for penetrating the transparent body, and the hole is provided with a fastening means for pressing and fixing the transparent body. (4) or (5) The parallel polishing apparatus described. (7) The parallel polishing apparatus according to (6), wherein the tightening means is formed by a pressing member that is provided in a hole of the jig and can move forward and backward, and a screw member that supports the pressing member and moves it forward and backward.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings. (I) Parallel Polishing Method In the parallel polishing method of the present invention, measurement light is made incident from one end face (measurement light on the incident side is called incident light), transmitted through the transparent body and emitted from the other end face. The measurement light (the measurement light emitted through the transparent body is called transmitted light) is measured, and the parallelism between the incident side end face and the transmission side end face is detected by the inclination angle of the transmitted light with respect to the optical axis of the incident light. In this method, both end faces are polished in parallel by polishing the end faces of the transparent body until the optical axes of the incident light and the transmitted light coincide with each other.

In the present invention, the term "transparent material" refers to a material that is transparent to the wavelength of measurement light. As long as the inside and both end faces of the transparent body are transparent to the measurement light, the other outer peripheral faces may be covered with an opaque material. As a general transparent body, it can be applied to crystalline or glassy ones. As the measuring light, a laser light having a high straightness is most suitable.

(A) Initial Polishing FIGS. 1 (a) and 1 (b) show an application example in which a large number of transparent bodies are integrally mounted on a plate-shaped jig and polished. 1 is attached to a plate-shaped jig 3. The jig 3
Is placed on the polishing platen 5, and the end faces of the respective transparent bodies protruding from the back surface of the jig 3 are slid on the polishing platen while being abutted against the polishing platen 5, and the lower end faces of these transparent bodies are simultaneously polished. In this case, a plurality of supporting pieces 6 having the same height may be interposed between the jig 3 and the polishing board 5 so that the jig 3 is kept parallel to the polishing board 5. During polishing, the lower end surface of the transparent body 1 is always the polishing plate 5
Since the height of the support piece 6 must be equal to the length of the lower end of the transparent body 1 so as to be in contact with, the support piece 6 is made of the same material as the transparent body 1. As the supporting piece 6 is polished and the heights of the jig 3 and the polishing board 5 are gradually lowered, the lower end surface of the transparent body 1 is simultaneously polished and the same height is always maintained. After polishing the end surface projecting to the front surface side of the jig 3, the jig 3 is inverted and the end surface projecting to the back surface side is polished.

(B) Parallelism measurement After polishing one side, the transparent body is removed from the polishing plate with the jig still attached, and the polished surface of the transparent body is irradiated with measurement light such as laser light. Detect parallelism. 2 (a) and 2 (b) are conceptual diagrams of the parallelism measuring method, in which 1 is a transparent body and 1 is a transparent body.
a is an incident side end face, 1b is a transmission side end face, 2 is measurement light, 2a is incident light, 2b is transmitted light, and 3 is a flat plate holding a transparent body. Further, θ1 is the angle of the transmission side end face with respect to the incidence side end face, θ2 is the refraction angle of the transmitted light with respect to the optical axis X of the incident light, and O
Is the optical axis position (optical axis point) of the incident light on the screen, and N is the projection point of the transmitted light on the screen.

The measuring light vertically incident on the incident side end face 1a of the transparent body 1 is transmitted through the inside of the transparent body and radiated to the outside from the transmitting side end face 1b. At this time, the transmitting side end face 1b of the incident light 2a. When it is tilted with respect to the optical axis, the transmitted light 2b is refracted according to this tilt angle θ1 and is emitted in a direction tilted by an angle θ2 with respect to the optical axis (extended straight line to the incident direction) X of the incident light 2a. To be done. This refraction angle θ2 is determined by the refractive index n of the transparent body and the inclination angle θ1 of the transmission side end surface 1b. Since the refraction index n is a unique value in the transparent body, from this refraction angle θ2, the inclination angle θ1 of the transmission side end surface 1b. Can be measured. In addition,
When the incident light 2a is obliquely incident on the incident side end surface 1a, the optical path inside the transparent body is bent due to the refractive index. By correcting this effect, the inclination angle θ1 of the transmitting side end surface 1b is corrected.
Can be measured. However, if the incident light 2a is incident vertically on the end face, such a correction is not necessary, so it is preferable that the incident light 2a be incident perpendicularly on the end face. Incident light 2a
In order to make the light incident vertically, the direction of the incident light 2a may be adjusted with respect to the incident end face 1a so that there is no reflection at the end face.

In order to measure the inclination angle θ2 of the transmitted light 1b with respect to the optical axis of the incident light 1a, as shown in FIG.
The tilt angle θ2 can be measured by providing the screen 4 behind the transmission side end face 1b and projecting the transmitted light 2b on the screen 4. Specifically, the inclination angle θ2 is measured by measuring the distance d from the optical axis position O of the incident light 2a defined on the screen 4 to the projection position N of the transmitted light 2b. This projection position N is the optical axis position O
Is separated from the optical axis position O by a distance d corresponding to the angle θ2 and projected in a range of 360 degrees according to the inclination direction of the end face 1b. Therefore, by measuring the distance d and the direction from the optical axis point O of the incident light 2a defined on the screen 4 to the projection position N of the transmitted light 2b, the magnitude and the direction of the inclination angle θ2 can be grasped. You can In addition,
If the screen 4 is provided with a scale centered on the optical axis point O, the distance d and the direction from the optical axis point O can be easily measured.

For example, when θ1 = 90 ° -δ with respect to the inclination angle θ1 of the incident side end face, the parallelism δ of the incident side end face is given by the following equation. tan δ = θ2 / (n-1) → tan θ2 / (n-1) tan θ2 = d / l (l is the distance from the sample to the screen)

In the above measuring method, the longer the distance between the screen and the material to be polished, the more precise the measurement can be made, and the inclination can be easily measured to an accuracy on the order of minutes. In the case where there is a space restriction or when the measurement accuracy is further improved, the measurement can be performed with an accuracy of up to about several seconds by using a measuring device such as a laser autocollimator.

According to the above measuring method, it is possible to continuously measure the parallelism of both end faces of many transparent bodies. That is, a large number of transparent bodies 1 are sequentially sent to the incident position of the measuring light 2, the transmitted light 2b is projected on the screen 4, and the distance d of the projected position of the incident light 2a with respect to the optical axis is sequentially measured to obtain the transparent bodies. It is possible to continuously measure the parallelism of both end faces of the.

As a means for sequentially sending a large number of transparent bodies to the incident position of the measuring light, a flat plate-shaped jig having a large number of transparent bodies arranged side by side may be used. Specifically, the flat plate used in the polishing step is used. Using a jig in the shape of a plate, place the above jig in the shape of a flat plate so that the end face of the transparent body faces perpendicularly to the measurement light while a large number of transparent bodies are stuck, and move the flat plate. By doing so, each transparent body may be sequentially sent to the measurement light incident position. At this time, by using the jig used in the polishing step for parallelism measurement while the transparent body is being stuck, the polishing step and parallelism can be continuously measured in a short time.

A disk is used as a flat jig, and a plurality of holes are provided along the circumference. The transparent body is inserted into the holes so that the end faces of the jig face the front surface or the back surface of the disk. With a structure in which a disc-shaped jig is rotatably supported so that the end surface of the transparent body faces perpendicularly to the measurement light, the transparent body on the disc can be rotated by the rotation of the jig. The parallelism of the end surface of the transparent body can be continuously measured by sequentially moving to the incident position.

(C) Corrected polishing As described above, after detecting the parallelism of both end faces of the transparent body, polishing of both side faces of the transparent body is repeated until the optical axes of the transmitted light and the incident light coincide with each other. Make the faces parallel. Here, since the inclination direction and the inclination angle of the transmission side end surface are measured by the distance d and the direction from the optical axis O to the projection point N, it is necessary to cancel the inclination of the transmission side end surface with a flat jig. A load of polishing pressure is applied.

For example, as shown in FIGS. 2A and 2B, the transmission side
The end face 1b (on the back side of the jig: side B) faces the screen 4 and inclines upward, so that the projection point N of the transmitted light is the optical axis O.
On the other hand, when the transparent bodies are located on the lower left side of the screen 4, the plurality of transparent bodies are integrally mounted on the jig 3 and polished, so that the end faces 1b of the respective transparent bodies have the same inclination. , Projection points Na to Nf of the measurement light transmitted through each transparent body
Are positioned at equal intervals on the same circumference with the optical axis O as the center, as shown in FIG. Therefore, as shown in FIG.
Either the intersection point h or g of the straight line XY that passes through the center of the jig 3 and extends in the inclination direction of the end surface 1b and the circumference formed by the projection points Na to Nf, in this case, the intersection point h It is advisable to provide a load application point P. The additional point P is added to the front surface (A surface) of the jig 3 when polishing the end surface protruding to the back surface (B surface) of the jig 3.

As an eccentric load adding means, for example, an eccentric concentrated load system using a weight or the like, an eccentric distributed load system using an eccentric weight, or the like can be used.
As a matter of course, the position of the load application point P and the magnitude of the load are arbitrarily determined within the range in which these samples do not float up during polishing.

(II) Parallel Polishing Device As shown in FIG. 1 (a), the parallel polishing device of the present invention is a flat plate-shaped device that holds the transparent body 1 and is used for both parallelism measurement and polishing of both ends of the transparent body. Jig 3 and the transparent body 1 attached to the jig 3
Means 20 for polishing the end face of the, and, as shown in FIG.
It has a means 10 for measuring the parallelism of both end faces of the transparent body 1 which penetrates the jig 3. As the flat plate-shaped jig 3, a flat plate having a large number of through holes for mounting a transparent body is used. As the parallelism measuring means 10, means 12 for irradiating the transparent body 1 penetrating the flat plate-shaped jig 3 with the measuring light 2 is used.
A supporting means 13 for moving the flat plate-shaped jig 3 while holding it so as to face the measuring light 2 in a direction perpendicular to the measuring light 2; and a screen 14 for projecting the measuring light 2 which has passed through the transparent body 1. The polishing means 20 includes a polishing board 5 for polishing the end surface of the transparent body 1 which is attached to the flat jig 3, and a means for applying a load to a predetermined position of the jig. A weight (not shown) or the like can be used as a means for applying a load.

As a preferred example of the parallelism measuring means, as shown in FIG. 3, a disk having a large number of through holes at equal intervals along the circumference is used as the jig 3, and the jig 3 is attached and detached. Also, a rotatably supported structure is used. According to this support structure, the transparent body 1 on the disk is sequentially moved to the incident position of the measuring light 2 by the rotation of the jig 3, and the parallelism of the transparent body end face can be continuously measured.

Further, preferably, the transparent body penetrating hole provided in the flat plate-shaped jig 3 is provided with a fastening means for pressing and fixing the transparent body. An example of the fixing means is formed by a pressing member that is provided in the penetrating hole and that can move forward and backward, and a screw member that supports the pressing member and moves it forward and backward.

A concrete example of the fixing means 30 is shown in FIGS. 6 (a) and 6 (b).
Shown in As shown, the disc-shaped jig 3 has a transparent body 1
A large number of holes 7 are formed along the circumference for penetrating. A pressing member 8 is provided inside the hole 7 so as to be able to move forward and backward, and the pressing member 8 is supported by a rod-shaped screw member 9. The screw member 9 is provided so as to penetrate the peripheral wall of the jig 3, and the head portion thereof projects to the outer periphery of the jig 3. A recess 31 into which the transparent body 1 is fitted is formed on the inner surface of the pressing member 8 and the hole 7 facing the pressing member 8. The pressing member 8 is moved forward and backward by the screw member 9 toward the inner surface of the hole 7 where the concave portion 31 is formed. In the fixing means 30, after the transparent body 1 is inserted into the hole 7, the screw member 9
The pressing member 8 is advanced by and the transparent body 1 is clamped between the inner peripheral surface of the hole 7 and the pressing member 8 and fixed in a state of being sandwiched in the recess 31. To remove the transparent body 1, the pressing member 8 is retracted by the screw member 9 and the tightening by the pressing member 8 is released.

As another means for fixing the transparent body, there is a method of inserting the transparent body into the hole of the jig, adjusting the protruding length, and then fixing the transparent body using a heat-soluble adhesive or the like. . In such a method of fixing with an adhesive, it is necessary to take care so that the adhesive does not adhere to the polishing surface and roughen the polishing surface when the transparent body is pulled out. It is necessary that no corrosion occurs on the part. According to the mechanical fixing means of the present invention, such a problem can be eliminated, the transparent body can be stably fixed, and the transparent body can be easily attached and detached, and the working time can be further shortened.

[0026]

Embodiments of the present invention will be described below. These examples do not limit the scope of the present invention. Example 1 Using a glass disk-shaped jig (diameter 10 cm, thickness 4.0 mm) in which a penetration hole is provided at a portion located at the apex of a regular hexagon, a quartz glass rod having substantially the same diameter as the penetration hole is used. After inserting (length 10 mm) into the penetration hole and holding it, as shown in FIG. 1, one side (A side) of the jig is inserted by inserting quartz glass of the same quality as the quartz glass rod on both sides of the jig. After maintaining a constant gap between the polishing plate and the surface of the polishing plate, the quartz glass rod was fixed to the jig with a heat-soluble adhesive. Then, using a polishing liquid containing diamond powder and a surfactant, the polishing platen is rotated with the lower end face of the glass rod pressed against the surface of the tin-lead polishing plate, and the lower end faces of the plurality of glass rods are removed. At the same time, lapping was performed. After polishing one surface, the jig was turned over and the lower end surface of the glass rod protruding to the back surface of the jig was similarly polished.

After polishing, remove the jig from the polishing plate,
As shown in FIG. 2, with the glass rod fixed to the jig, He-Ne laser (wavelength 632.81 nm) light was vertically incident on one (A side) polishing surface and the other side (A side). (B side)
The transmitted light radiated from the end face of was projected onto the screen, and the distance and direction between the optical axis O of the incident light and its projection point N were measured. Subsequently, the jig is rotated to rotate the adjacent glass rod a.
The projected points Na to Nf were continuously measured for .about.f. The results are shown in FIGS. 4 (a) and 4 (b). As shown in the figure, since each projection point Na to Nf is located at the apex of a regular hexagon similar to the mounting position of the glass rod, the end faces on the transmitted light side are inclined in the same direction (XY direction in the figure). You can see that Here, in the plane connecting the rod end faces, Ng
Is the lowest and Nh is the highest.

Subsequently, the jig is attached to the polishing apparatus again,
The B side was corrected and polished. The correction polishing was performed by applying a load to the intersection P between the circumference connecting the glass rods mounted on the jig and the extension line extending in the XY direction from the center of the jig (Fig. 4 (a ), FIG. 5). After the correction polishing, the parallelism of both end faces was measured in the same manner as above, and it was confirmed that the projected points of the rods were concentrically close to the O point. By repeating this operation, the projection point was almost aligned with the optical axis O. At this time, the parallelism of both polished surfaces was calculated to be about 2 minutes. After that, the load amount was reduced, and the correction polishing was performed while measuring the inclination using the autocollimator, whereby the parallelism of about 5 seconds was obtained. After polishing, the bonded portion was heated to melt the adhesive and the glass rod was removed from the jig.

Example 2 A glass disk-shaped jig shown in FIG. 6 (diameter 10 cm, thickness 4.0 m)
m), a chloride (70GdCl ₃ -30BaCl ₂ ) glass rod (length 10 mm) was inserted, and then the glass rod was clamped and fixed to the jig by the fixing means 30. Others are Example 1.
The parallelism measurement and polishing were repeated in the same manner as above to obtain a glass rod having a parallelism of about 5 seconds. In this embodiment, the glass rod is attached and detached in a short time.
Working time has been greatly reduced compared to.

[0030]

According to the polishing method and apparatus of the present invention,
The parallelism of both end faces of the glass member can be easily measured, and since the parallelism can be continuously measured and the end faces can be polished without removing many members from the jig, the work efficiency is remarkably excellent. . Further, even when the correction polishing is performed so that the both end surfaces are parallel to each other, it is possible to easily grasp the point and the size of the load applied to the jig, and therefore the work efficiency of the correction polishing is excellent. INDUSTRIAL APPLICABILITY The present invention can be preferably used for polishing various glass materials, polymers and the like, and is particularly useful for polishing laser oscillators and the like which require precise parallelism.

[Brief description of the drawings]

1A is a perspective view showing a polishing method, and FIG. 1B is a partial sectional view thereof.

2A is a conceptual diagram showing a measuring method of the present invention, and FIG. 2B is a perspective view showing a measuring system.

FIG. 3 is a conceptual diagram showing a device configuration example of the present invention.

4 (a) and 4 (b) are conceptual diagrams showing a measuring method in an example of the present invention.

FIG. 5 is a cross-sectional explanatory view showing a state in which an eccentric load is added in correction polishing.

6A is a front view showing an example of a jig of the present invention, and FIG. 6B is a partial perspective view thereof.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transparent body, 2 ... Measuring light, 3 ... Jig, 4 ... Screen, 5 ... Polishing board, 6 ... Supporting piece, 8 ... Pressing member,
9 ... Screw member

Claims (7)

[Claims] 1. A method for polishing both end surfaces of a transparent body in parallel, wherein measuring light is incident from one end surface, and transmitted light which is transmitted through the transparent body and radiated from the other end surface is measured, The parallelism of both end surfaces of the transparent body is detected by the inclination angle of the transmitted light with respect to the optical axis of the incident light, and the both end surfaces of the transparent body are polished until the optical axes of the incident light and the transmitted light are aligned. A method for polishing a transparent body, which comprises polishing in parallel. 2. A jig for applying a load for eliminating the inclination of the end face of the transparent body detected by measuring the parallelism of both end faces of the transparent body in a state where the transparent body is attached to the plate-shaped jig. The polishing method according to claim 1, wherein both end surfaces of the transparent body are polished in parallel by polishing in addition to. 3. A plurality of transparent bodies are attached to a flat jig,
The polishing method according to claim 2, wherein parallelism measurement and polishing of both end faces of each transparent body are simultaneously performed on a plurality of transparent bodies. 4. A flat plate-shaped jig which holds a transparent body and is used for parallelism measurement and polishing of both ends of the transparent body, and a parallelism of both end faces of the transparent body which penetrates the jig. A parallel polishing apparatus for both ends of a transparent body, comprising: a means and a means for polishing an end surface of the transparent body which is attached to the jig. 5. (a) A means for irradiating a transparent member penetrating a flat plate-shaped jig with measuring light by parallelism measuring means at both ends of the transparent member, and the flat plate-shaped jig for the measuring light. And a screen for projecting the measurement light that has passed through the transparent body, and a support means for sending the transparent body on the jig to the incident position of the measurement light by moving it while holding it so that it faces vertically. 5. The polishing apparatus according to claim 4, wherein the polishing means includes a polishing disk that polishes the end surface of the transparent body that is attached to the flat jig, and a means that applies a load to a predetermined position of the jig. 6. The plate-shaped jig is provided with a hole for penetrating the transparent body, and a fastening means for pressing and fixing the transparent body is attached to the hole. Parallel polishing equipment. 7. The parallel polishing apparatus according to claim 6, wherein the tightening means is formed by a forward / backward movable pressing member provided in a hole of the jig and a screw member for supporting the pressing member to move forward / backward.