JP3329003B2 - Hologram optical element fixing mechanism of hologram interferometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a lens, a plane parallel plate,
The present invention relates to a mechanism for fixing a hologram optical element to a support member in a hologram interferometer apparatus for measuring a surface state of an object to be measured such as a mirror or other precision optical parts.

[0002]

2. Description of the Related Art An interferometer is used to precisely measure the surface shape of a lens or other object in a non-contact manner. A typical example of this interferometer is a Fizeau-type interferometer as shown in FIG.

In FIG. 1, reference numeral 1 denotes an apparatus main body. The apparatus main body 1 has a main body casing 1a and a tubular body 1b vertically suspended from a lower surface of the main body casing 1a. A laser light source 2 made of a He-Ne laser or the like is attached to the main body casing 1a in parallel with the cylindrical body 1b. Inside the main body housing 1a, the reflection mirror 3,
The laser beam from the laser light source 2 is provided with a diverging lens 4 and a pinhole 5. The laser beam is bent 90 ° by the reflecting mirror 3, passes through the diverging lens 4, and passes through the diverging lens 4.
After passing through the pinhole 5 disposed at the light condensing position, while diverging and widening the spot diameter, the laser beam is reflected by the beam splitter 6 and changes its direction again by 90 °, so that the laser beam extends along the axial direction of the cylindrical body 1b. The light travels from the light source 2 in the direction opposite to the emission direction, is converted into a parallel light beam by the collimator lens 7, and is incident on the reference lens 8 provided in front of the light beam.

The reference lens 8 has a surface opposite to the entrance surface 8a serving as a reference surface 8b having, for example, a spherical shape, and the entrance surface 8a is coated with an antireflection coating. A part of the laser beam incident on the reference lens 8 is reflected by the reference surface 8b, and most of the laser beam passes through the reference lens 8 and is transmitted to the surface 9a of the lens 9 to be measured which is set in front of the lens. The light is incident and a part of the light is reflected by the surface 9a to be detected. Then, the reflected light from the test surface 9a and the reflected light from the reference surface 8b of the reference lens 8 interfere with each other to generate interference fringes.
The reflected light having the interference fringes is transmitted to the collimator lens 7.
Then, the light passes through the beam splitter 6 and is incident on the imaging unit 12 via the screen 10 and the interference fringe imaging lens 11, and the imaging unit 12 captures the interference fringe.
The video can be displayed on a monitor device.

[0005] In recent years, a hologram interferometer for measuring the surface condition of an object to be measured by using a computer-generated hologram has been put to practical use. Computer-generated holograms are obtained by applying a photoresist film on a glass substrate and scanning the photoresist film with an electron beam to expose an interference fringe pattern equivalent to the interference fringe between the object wave and the reference wave. Is an optical element in which interference fringes are made visible by developing When the same reproduction wave as the reference wave enters the interference fringes in the hologram optical element, the object wave can be reproduced. According to the interferometry using this hologram, it is possible to inspect / measure a special shape, etc., so that it is expected to be widely used in the future.

[0006]

As a hologram interferometer using the interferometer shown in FIG.
The present applicant has developed the configuration shown in FIG.

This hologram interferometer has the same structure as the main body 1 of the interferometer described above. However, the reference lens 8 corresponding to the test lens 9
Is not used. That is, in this hologram interferometer apparatus, the apparatus main body 1 from which the reference lens 8 has been removed is connected to the laser light source 2.
A light source unit having a light path provided with an optical path for guiding the laser light from the laser light source 2 into a parallel light beam and emitting incident light to an interference fringe observation mechanism, and an observation unit such as the imaging unit 12. Since the light source / observation unit is used as a mechanism that exerts the function of the observation unit, the light source / observation unit will be denoted by 1L in the following.

The laser light from the laser light source 2 is emitted by the light source / observation unit 1L in a state where the laser light is converted into a parallel light beam by the collimator lens 7. The parallel light is first reflected by the first reflection mirror 20 and then reflected by the second reflection mirror 21 to direct the optical path of the laser light upward. Then, the second reflection mirror 2
The laser light from 1 is once turned back by the third reflection mirror 22, and the laser light turned back by the third reflection mirror 22 is reflected by the fourth reflection mirror 23. A hologram optical element 24 is provided to face the fourth reflection mirror 23. When a laser beam enters the hologram optical element 24, the laser beam is divided into regular reflection light and diffraction light. In the optical path of the regular reflection light, a reference reflection plate 25 having a reference reflection surface 25a perpendicular to the regular reflection light is provided.

On the other hand, a test object 26 is arranged in the optical path of the diffracted light. Here, assuming that the test object 26 is, for example, a cylindrical lens having a concave curved surface shape, the hologram pattern of the hologram optical element 24 is a lattice pattern arranged in parallel straight lines. Then, the hologram optical element 24
The lattice direction of the cylindrical surface 26 of the test object 26
It is arranged in the direction of the generatrix a and at a position where the diffracted light is condensed at the central axis.

With the above-described configuration, the laser beam from the laser light source 2 in the light source / observation unit 1L passes through the diverging lens 4 and the pinhole 5 constituting the light transmitting optical system, and then becomes a beam splitter. After being reflected by 6 and collimated by a collimator lens 7,
The light enters the hologram optical element 24 through the first to fourth reflection mirrors 20 to 23. Then, the diffracted light emitted from the hologram optical element 24 is once condensed at a position on the central axis of the test surface 26a formed of a cylindrical surface of the test object 26, then diverges, and irradiates the test surface 26a. Then, the light is reflected by the test surface 26a and returns to the hologram optical element 24.
The return light from the test object 26 is transmitted to the hologram optical element 24.
, And returns to the collimator lens 7 as original parallel light. On the other hand, the regular reflection light from the hologram optical element 24 is reflected by the reference reflection surface 26a of the reference reflection plate 25, and the return light is reflected again by the hologram optical element 24 and travels toward the collimator lens 7.

Accordingly, the object wave light of the pattern of the hologram optical element 24 overlaps with the reference wave light from the reference reflection plate 25 and causes interference with each other, thereby forming interference fringes. This light passes through the beam splitter 6 and forms an interference fringe on the imaging plane of the imaging unit 12 via the interference fringe imaging lens 11 provided at the rear focal position of the collimator lens 7. Thus, the plane wave and the test surface 26a of the test object 26 are actuated by the action of the hologram optical element 24.
Is converted to an aspherical wave corresponding to the above, and the interference fringe is generated as a result of interference between parallel lights. Therefore, the shape of the test surface 26a can be measured with extremely high accuracy.

Here, the hologram optical element 24 is
Are reflected from the reflection mirror 23, and reflect the diffracted light to the test object 26 and the specularly reflected light to the reference reflection plate 25, so that the light is accurately positioned at a predetermined position. Must be located. For this purpose, it is attached to a holder member fixed to the main body housing of the interferometer device. In particular, it is necessary to use a hologram optical element on a frame member to form a hologram cassette, since a hologram cassette having different hologram patterns must be used depending on the type of the test object. Is appropriately replaced with a holder member so that various kinds of test objects can be measured using a single interferometer device, which is extremely convenient.

Regardless of whether the hologram optical element is directly mounted on the holder member or mounted on a frame-shaped member of the hologram cassette, the hologram optical element must be mounted in an accurately positioned state. Particularly strict positioning is required on the surface on which the hologram pattern is formed. Therefore, a predetermined reference surface is formed on the mounting member side, and the hologram pattern of the hologram optical element is mounted on the reference surface. There is a need. Moreover, the hologram optical element must be fixed to the mounting member using, for example, an adhesive.

If the hologram optical element is fixed to the mounting member via an adhesive layer, the hologram optical element will be inclined unless the thickness of the adhesive layer is made uniform. When the hologram optical element is tilted in this way, it becomes impossible to perform positioning with respect to a test object or the like. However, when the hologram optical element is pressed against the reference plane to accurately position the hologram optical element, the hologram optical element is distorted.
It is not possible to apply too much pressing force. Therefore, it is conceivable to make the adhesive layer as thin as possible. However, in such a case, there arises a problem that the hologram optical element cannot be stably held.

The present invention has been made in view of the above points, and has as its object to fix a hologram optical element in a state where it is accurately positioned on a support member to which it is attached. is there.

[0016]

In order to achieve the above-mentioned object, the present invention provides a laser beam from a laser light source which is converted into a parallel light beam and emitted, and this laser beam is incident on a hologram optical element and is specularly reflected. The object light and the reference light are generated by irradiating the specular reflected light to the reference reflector and the diffracted light to the test object separately into light and diffracted light, and the light is generated between the two wavefronts. A hologram interferometer apparatus for measuring a surface state of a test object based on interference fringes, wherein a receiving portion serving as a reference surface is formed over the entire circumference by providing a step on an inner wall of a frame-shaped support member. Holographic optics
The element is the surface on which the hologram pattern is formed, and
Outside the area where this hologram pattern is formed
The location is mounted so that it is joined to the receiving part via adhesive.
And a lid is attached to the support member,
Opposed to the surface of the inner surface of this lid on which the adhesive is applied
Pad made of an elastic member is fixed
The pad is provided with the lid attached to the support member;
Is pressed against the hologram optical element,
The hologram optical element is not distorted and
Gram optical element is horizontal with respect to the reference plane of the receiving part.
It is characterized in that the adhesive layer is configured to have a uniform thickness so as to protrude .

[0017]

When the hologram optical element is mounted on the support member, an adhesive is first applied to the support member or the hologram optical element. Here, the bonding is performed on the hologram pattern forming surface side of the hologram optical element, but the adhesive is not applied to the region where the hologram pattern is formed. And, for example, when applying an adhesive to the hologram optical element, the adhesive is applied uniformly,
It is mounted so as to follow the receiving portion of the support member. In this state, the lid is attached to the support member, and the pad fixedly provided on the inner surface of the lid comes into contact with the hologram optical element and presses it against the receiving portion. Here, since the pad is in pressure contact with the outer peripheral edge of the hologram optical element, the entire area to which the adhesive is applied is pressed, and the hologram optical element does not become inclined. .

A hologram cassette is prepared by using a cassette body formed in a frame shape as a support member of the hologram optical element, mounting a hologram optical element at a predetermined position on the cassette body, and mounting a lid on the cassette body. If the hologram cassette is configured to be detachably attached to the holder member, the hologram cassette can be exchanged according to the test object. When configured as a hologram cassette in this way, the hologram optical element must be fixed to the cassette body in an extremely stable state. If the adhesive layer is thinned in order to fix the hologram optical element so as not to tilt, the adhesive may be peeled off when the hologram cassette is attached to or detached from the holder main body. However, since the lid is provided with a pad and a force for constantly pressing the hologram optical element against the receiving portion acts, the stability of the hologram optical element is significantly improved, and even if a slight external force is applied. There is no risk of the adhesive being peeled off. Here, if a too strong pressing force acts on the pad, the hologram optical element may be distorted. For this,
As the pad, it is preferable to use an extremely flexible member such as maltoprene.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an exploded perspective view of the hologram cassette, FIG. 2 is a plan view of the assembled state, FIG. 3 is a cross section of the assembled state, FIG. 4 is a plan view of the holder member, and FIG. Are respectively shown. Further, FIG.
Shows a front view of a state where the hologram cassette is mounted on the holder member. In these figures, 30 is a hologram cassette, and 50 is a holder member.

The hologram cassette 30 includes a frame-shaped cassette body 31 and a lid 32. The cassette body 31 is formed of a frame-shaped member and has an opening 31.
A hologram optical element 34 is mounted on a. The hologram optical element 34 is connected to the opening 31a.
In order to hold the hologram optical element 34 mounted on the inside of the hologram optical element 34, an inwardly protruding receiving portion 31b is formed at the bottom of the hologram. Notch 3
1c is formed.

The hologram optical element 34 has a hologram pattern on one side of which a hologram pattern having an interference fringe equivalent to the interference fringe generated between the object wave and the reference wave according to the surface shape of the test object is formed. The opposite side of the pattern forming surface 34a is an anti-reflection type light absorbing layer forming surface 34b which is provided with a coating for preventing reflection and absorbing light. The hologram optical element 34 has a considerable thickness in order to prevent deformation or distortion due to heat or external force. The hologram optical element 34 having such a configuration is mounted on the cassette body 31 as a support member, and the hologram pattern forming surface 3
4a is accommodated in a state facing the receiving portion 31b side, and is fixed using an adhesive. Therefore, the receiving portion 31b functions as a reference surface for positioning the hologram optical element 34. Then, with the hologram optical element 34 incorporated in the cassette main body 31, the lid 32 is brought into contact with the cassette main body 31, and
The hologram cassette 30 is assembled by fastening the screws 35 to the corners of the location.

The hologram cassette 30 assembled in this manner is detachably attached to the holder member 50. The holder member 50 includes, for example, a support portion 51 fixed to a housing of the interferometer unit.
And a frame portion 52 is continuously provided. The hologram cassette 30 is joined to an upper portion of the frame 52 and is fixed using a pair of bolts 53 provided at the front and rear.

Here, the hologram optical element 34 must be accurately positioned in the cassette main body 31. The hologram optical element 34 has a hologram pattern forming surface 34a which is a reference surface of the cassette main body 3.
The first receiving portion 31b is brought into contact with the first receiving portion 31b, and the receiving portion 31b is processed so as to be accurately flat,
The hologram optical element 34 is fixed in a state in which the hologram optical element 34 is not tilted and has an accurate flatness. On the other hand, in order to accurately determine the position in the horizontal direction, the inner peripheral wall 3 of the opening 31a is required.
1d is used as a positioning wall.

The hologram cassette 30 includes the holder member 5
0 of the hologram cassette 3
The bolt 53 is inserted through a pair of insertion holes 36 provided in
By screwing the bolt 53 into a screw hole 54 formed in the frame 52, the bolt 53 is detachably connected and fixed to the holder member 50. At this time, in order to adjust the position of the hologram cassette 30, positioning pins 55, 55 are protrudingly provided on the left and right portions of the frame portion 52, and the positioning pins 55 are provided on the hologram cassette 30 side. A pin insertion hole 37 into which is inserted.

As described above, the hologram optical element 34 is attached to the receiving portion 31b of the cassette main body 31 and is fixed to the inner peripheral wall 31d as described above. Must be positioned at Therefore, first, in order to set the position in the horizontal direction, the inner peripheral wall 31d that defines the opening 31a in the cassette body 31 is used as a horizontal positioning portion. However, in order to smoothly drop the hologram optical element 34 into the opening 31a, the dimension is very small, though slightly, between the outer dimension of the hologram optical element 34 and the inner dimension of the inner peripheral wall 31d that defines the opening 31a. We must make a difference. For this purpose, a mechanism for correcting the position of the hologram optical element 34 is required. This position correction mechanism has the configuration shown in FIGS. That is,
A position adjusting recess 38 is provided on the bottom surface of the cassette main body 31, and an adjusting plate 39 is fitted into the position adjusting recess 38. The above-mentioned pin insertion hole 37 is formed in this adjustment plate 39. In addition, screw holes 40, 40 are formed in the adjustment plate 39 on both sides of the pin insertion hole 37. Further, screw insertion holes 41, 41 are formed in the cassette body 31, and screw accommodation recesses 43, 43 for accommodating plate fixing screws 42, 42 are provided on the upper surface side thereof. The head of the plate fixing screw 42 does not protrude from the upper surface of the cassette body 31. The plate fixing screw 42 is inserted into the screw insertion hole 41 from the screw accommodating recess 43 side, and is screwed into the screw hole 40 of the adjustment plate 39 fitted in the position adjusting recess 38 so that the adjustment plate 39 is screwed. It is configured to be fixed so as to be pressed against the inner surface of the position adjusting recess 38.

The diameter of the screw insertion hole 41 is formed larger than the outer diameter of the plate fixing screw 42, and the outer dimension of the adjustment plate 39 is smaller than the position adjusting recess 38. When fitted into the position adjusting recess 38, it is in a state in which it can move back and forth and left and right by a predetermined amount. However, adjustment plate 3
9 has a thickness equal to or less than the depth of the position adjusting recess 38. By moving the adjustment plate 39 in an arbitrary direction, the position of the pin insertion hole 37 into which the positioning pin 55 provided on the frame 53 of the holder member 50 is inserted can be adjusted. Moreover, the hole diameter of the insertion hole 36 is also larger than the outer diameter of the bolt 53, so that the hologram cassette 30 itself is
Even if the position is slightly shifted from 0, it can be fixed.

Next, the hologram optical element 34 must be mounted horizontally. The cassette body 31 has a receiving portion 31 serving as a reference surface of the hologram optical element 34.
Since b is provided, if it is mounted so as to accurately follow the receiving portion 31b, the horizontality can be obtained. In order to fix the hologram optical element 34 in a fixed manner, the hologram pattern forming surface 34a of the hologram optical element 34 is coated with an adhesive at a position outside the area where the hologram pattern is formed. This adhesive surface is joined to the substrate. And if you do not make this adhesive layer uniform thickness,
The hologram optical element 34 will be mounted in an inclined state. From the above, the cassette body 31
The hologram optical element 34 is pressed against the receiving portion 31b by using the lid 32 attached to the hologram. For this purpose, the hologram optical element 34 is provided on the inner surface of the lid 32.
A pad 44 is fixedly provided at a position facing the adhesive applied to the substrate. The pad 44 is made of an extremely flexible member such as, for example, maltprene.
Is attached to the cassette body 31 so as to exert a predetermined pressing force. Here, the pressing force by the pad 44 is set such that no distortion occurs in the hologram optical element 34 and the hologram optical element 34 can be stabilized. The adjustment of the pressing force can be appropriately set according to the material and thickness of the pad 44.

The hologram cassette 30 is constructed as described above, and a method of assembling the hologram cassette 30 will be described below.
First, an adhesive is applied so as to surround a region where the hologram pattern is formed on the hologram pattern forming surface 34a of the hologram optical element 34. Here, the adhesive layer is managed so as to have a uniform thickness. The hologram optical element 34 is mounted so as to drop into the opening 31a of the cassette body 31. Thereafter, the hologram optical element 34 is moved to the receiving portion 31b of the cassette body 31.
Hologram optical element 34
The position of the hologram optical element 34 in the horizontal direction is adjusted by attaching the lid 32 to the cassette body 31.

That is, when the lid 32 is fastened to the cassette main body 31 with the screw 35, the pad 44 is pressed against the outer peripheral edge of the anti-reflection type light absorption layer forming surface 34b of the hologram optical element 34, and this hologram optical element The adhesive of 34 is pressed against the receiving portion 31b. In addition, since the pressing force becomes uniform as a whole, it follows the surface of the receiving portion 31b. As a result, the hologram optical element 34 is maintained at an accurate horizontal state without inclination. When the cover 32 is mounted, the pad 44 is always in pressure contact with the outer peripheral edge of the antireflection type light absorption layer forming surface 34b of the hologram optical element 34, so that the hologram optical element 34 is stable. Even if the adhesive layer between the hologram optical element 34 and the receiving portion 31b is thinned in order to maintain the state and make the thickness of the adhesive layer uniform, the adhesive is peeled off and the hologram optical element There is no inconvenience such as the misalignment of the position 34.

The hologram cassette 30 assembled as described above has no inclination and maintains the horizontal level, but the position in the horizontal plane may not be accurately obtained. Therefore, the position in the horizontal direction is adjusted. For this purpose, the hologram cassette 30 is mounted on the holder member 50 and held in a state in which the hologram cassette 30 is not fixed with the bolt 53. Then, the plate fixing screw 42 is loosened to adjust the adjustment plate 39.
Can be freely moved in the position adjusting recess 38 of the cassette body 31. In this state, a laser beam is made incident on the hologram optical element 34 to irradiate the test object with diffracted light, and the interference fringe image is obtained by the imaging means. By moving the hologram cassette 30 in an appropriate direction during this time, a position where the number of interference fringes is minimized is selected. As a result, the position of the hologram optical element 34 can be adjusted with respect to the holder member 50. Hologram optical element 34
When the position adjustment is performed, when the plate fixing screw 42 is tightened, the adjustment plate 39 is fixed to the cassette main body 31 in the posture state at this time. As described above, by adjusting the position and the direction of the adjustment plate 39 having the pin insertion hole 37, the hologram optical element 34 can be held without being affected by the positional relationship between the hologram cassette 30 and the hologram optical element 34. The position of the member 50 can be accurately adjusted.

Therefore, when actually measuring the test object,
The hologram cassette 30 is mounted on the holder member 50 by attaching and detaching the bolt 53 from the holder member 50 so that the positioning pin 55 is inserted into the pin insertion hole 37 of the adjustment plate 39, and the bolt 53 is tightened. Thus, accurate positioning of the hologram optical element 34 can be performed by an extremely simple operation of merely fixing the hologram cassette 30 to the holder member 50. As a result,
The hologram interferometer apparatus can be made versatile by replacing and using the hologram cassette 30 according to the test object. Further, in the hologram cassette 30, the hologram optical element 34 is held in a state of being pressed against the receiving portion 31b by the pad 44 provided on the lid 32, so that when the hologram cassette 30 is replaced, external force or the like is applied thereto. Even if it is added, there is no possibility that the adhesive for fixing the hologram optical element 34 is peeled off.

Although the hologram optical element is mounted on the hologram cassette, the hologram optical element may be directly mounted on a support member such as a holder member fixed to the main body of the apparatus. . In this case, a receiving portion serving as a reference surface may be formed on the inner wall portion of the support member. Also, the hologram optical element has an anti-reflection type light absorption layer formed on the surface opposite to the surface on which the hologram pattern is formed, and the light passing through the hologram pattern formation surface is absorbed by the anti-reflection type light absorption layer. In the case where the light is absorbed by the layer but the light is not completely absorbed by the light absorbing layer, the light is absorbed by applying a black paint to the inner surface of the lid, particularly the portion inside the portion where the pad is provided. By exerting the function, and by applying a matte finish to the coating surface of the coating material, it is preferable to configure the device so as to diffuse the light reflected from the inner surface of the lid, albeit slightly, by making it a diffusion surface. .

[0033]

As described above, the present invention provides a hologram in which a receiving portion serving as a reference surface is formed over the entire circumference by providing a step on an inner wall of a frame-shaped support member.
The optical element comes into contact with this receiving part via adhesive.
It is attached, and the lid is attached to the support member,
Adhesive of the receiving part is applied to the inner surface of this lid
The pad made of the elastic member is fixed at the position facing the surface
When the lid is attached to the support member, this pad
Is pressed against the hologram optical element,
This hologram optical element does not cause distortion
Adhesive layer so that it is level with respect to the reference surface of the receiving part
When the hologram optical element is fixed to the receiving portion of the supporting member, the pad provided on the inner surface of the lid body forms the base of the receiving portion when the hologram optical element is fixed to the receiving portion of the supporting member.
The hologram optical element can be fixed in a state in which it accurately follows the reference plane without tilting and maintains the horizontal level accurately.Moreover, the hologram optical element is always pressed against the receiving part with a predetermined pressing force by the pad. The adhesive layer will be retained
Even if this adhesive layer is thinned to achieve a uniform
Agent without the peeling, even if external force is applied such as when the detachable to e <br/> holder member and the hologram cassette, etc. will not cause problems such as holographic optical element is positioned shifted vain It works.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a hologram cassette showing one embodiment of the present invention.

FIG. 2 is a plan view of the hologram cassette in an assembled state.

FIG. 3 is a sectional view taken along line XX of FIG. 2;

FIG. 4 is a plan view of a holder member.

FIG. 5 is a front view of FIG. 4;

FIG. 6 is a sectional view of an assembled state of the hologram cassette and the holder member.

FIG. 7 is an explanatory diagram of a configuration of a position shift correction mechanism of the hologram optical element.

FIG. 8 is a sectional view taken along the line YY of FIG. 6;

FIG. 9 is a diagram illustrating the principle of a Fizeau interferometer.

FIG. 10 is a diagram illustrating the principle of a hologram interferometer.

[Explanation of symbols]

 Reference Signs List 30 hologram cassette 31 cassette body 31a opening 31b receiving part 32 lid 34 hologram optical element 36 insertion hole 37 pin insertion hole 38 position adjustment concave part 39 adjustment plate 40 screw hole 41 fixing screw insertion hole 42 plate fixing screw 44 pad 50 holder Element

Claims (2)

(57) [Claims] 1. A laser light from a laser light source is converted into a parallel light beam and emitted. The laser light is incident on a hologram optical element, is divided into regular reflection light and diffraction light, and the regular reflection light is transmitted to a reference reflection plate. By irradiating the test object with diffracted light,
In a hologram interferometer apparatus that generates object light and reference light and measures the surface state of a test object based on an interference fringe generated between the two wavefronts, a step is formed on an inner wall of a frame-shaped support member. The receiving part that becomes the reference plane is formed all around the
And the hologram optical element forms a hologram pattern.
Surface and the hologram pattern is formed
The position outside the area that is
A lid is attached to the support member, and an inner surface of the lid is attached.
Elastic at the position facing the surface on which the adhesive is applied
A pad made of a member is fixedly provided, and the pad is provided when the lid is attached to the support member.
The hologram optical element is pressed into contact with the hologram optical element.
This hologram does not cause any distortion in the ram optical element.
Optical element is level with respect to the reference plane of the receiving part
A hologram optical element fixing mechanism for a hologram interferometer device , wherein the adhesive layer has a uniform thickness . 2. A hologram optical element fixing mechanism for a hologram interferometer according to claim 1, wherein said pad is formed of moltoprene.