JPH0452731Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention is used in polarimeters, ellipsometers, circular dichroism dispersion meters, etc., and modulates the light passing through the optical medium by transmitting the distortion generated by applying an alternating voltage to the piezoelectric element to the optical medium. This invention relates to a stress plate modulator.

[Conventional technology]

3 and 4 show conventional stress plate modulators. Fig. 3 is a partially sectional front view of the main parts of the stress plate modulator;
The figure is a left side view. In the stress plate 10, one longitudinal end of a rectangular quartz glass plate 14 is bonded to one longitudinal end of a rectangular quartz plate 12. An electrode film is attached to a pair of wide surfaces of the crystal plate 12, and by applying an alternating current voltage to the electrode film, the crystal plate 12 is caused to resonate, and a longitudinal wave is transmitted to the quartz glass plate 14. 14 to resonate and form a standing wave. Then, the phase difference between two linearly polarized light components whose vibration directions are perpendicular to each other is periodically changed for the light that passes through the center point Q of the quartz glass plate 14 and is transmitted in a direction perpendicular to the plane of the paper. At this time, at the center point P of the crystal plate 12 and the center point Q of the quartz glass plate 14, the displacement in the longitudinal direction is always 0 (the amplitude of strain is maximum) with respect to longitudinal waves, as shown in FIG. Therefore, conical protrusions 16 and 18 are fixed to a pair of side surfaces in the width direction sandwiching the center point P of the crystal plate 12,
Similarly, conical projections 20 and 22 are fixed to a pair of widthwise side surfaces of the quartz glass plate 14 sandwiching the center point Q. On the other hand, on both sides of the side plate 24,
The upper plate 26 and the lower plate 28 are fixed at right angles to the upper plate 26 and the lower plate 28, shallow circular holes are formed in the upper plate 26 and the lower plate 28 corresponding to the positions of the protrusions 16-22, and cylindrical rubber 30-30 are respectively formed in these circular holes. One end of 36 is fitted. Protrusions 16 to 22 are fitted into holes at the other ends of the cylindrical rubbers 30 to 36, respectively, to support the stress plate 10 so that it can freely vibrate.

[Problem that the idea aims to solve]

However, the protrusions 16-22 and the cylindrical rubber 30-3
Since the contact between the cylindrical rubber 30 and the cylindrical rubber 6 is not at one point, and the diameter of the contact circle needs to be about 4 mm for stable support, the cylindrical rubber 30 to 36 vibrate at these contact parts. For this reason, in an attempt to stably support the stress plate 10, the protrusions 16 to 22 and the cylindrical rubber 30 to
If the coupling with 36 is strengthened, the optical modulation characteristics will change. On the other hand, if this bond is weakened, the change in the position of the stress plate 10 over time due to fatigue of the cylindrical rubbers 30 to 36 will increase, and the stress plates and reflectors (not shown) arranged near both ends of the stress plate 10 in the longitudinal direction will become larger. The distance from the end face of 10 changes, and the modulation characteristics change. In this way, the support structure of the stress plate 10 greatly influences the light modulation characteristics of the stress plate modulator and is an important point ("Principles and Applications of Stress Plate Modulator", Spectroscopy Research, Vol. Volume 29, No. 5, 1980, No. 301
~320 pages). In view of these problems, an object of the present invention is to provide a stress plate modulator that can stabilize modulation characteristics over a long period of time.

[Means to solve the problem]

In order to achieve this purpose, in the present invention, one longitudinal end of a transparent second rectangular plate is fixed to one longitudinal end of a first rectangular plate that exhibits a piezo effect, and an alternating current voltage is applied to the first rectangular plate. vibrating the first rectangular plate and transmitting longitudinal waves of the vibration to the second rectangular plate,
In the stress plate modulator that modulates the light transmitted through the second rectangular plate, a rubber-like material is provided on one side in the width direction corresponding to the point where the displacement in the longitudinal direction of the first rectangular plate becomes 0 during the vibration. A first rod member having a coefficient of thermal expansion substantially the same as that of the first rectangular plate is bonded with an adhesive such that the longitudinal direction thereof is perpendicular to the longitudinal direction of the first rectangular plate, and when the vibration occurs, A second rod member with a coefficient of thermal expansion that is approximately the same as that of the second rectangular plate is attached to one side in the width direction of the second rectangular plate corresponding to the point where the displacement in the longitudinal direction becomes 0, using an adhesive that becomes rubber-like. The first rectangular plate is bonded with its longitudinal direction perpendicular to the longitudinal direction of the first rectangular plate, grooves are formed in the bottom plate corresponding to the first and second rod members, and the bottom plate is inclined with respect to a horizontal plane. The first and second rectangular plates are supported on the bottom plate by placing the first and second rod members in the grooves. The adhesive preferably has a thickness of 0.3 to 0.7 mm
The width is 2.0~3.0mm.

[Effect]

According to the support structure of the present invention, the first and second rectangular plates are supported via an adhesive that is an elastic body,
In addition, since the first and second rectangular plates and this elastic body are in surface contact with each other, it can be supported at two locations instead of the conventional four locations, and the modulation characteristics are improved compared to the conventional one. can also be stabilized over long periods of time. Furthermore, since it is possible to support a product at two locations instead of four in the past, the probability of product failure (if even one support point is defective, the product will be defective) is reduced compared to the past.

【Example】

Hereinafter, one embodiment of the present invention will be described based on the drawings. FIG. 1 is a front view of the main parts of the stress plate modulator, and FIG. 2 is an exploded perspective view of the main parts of the stress plate modulator. The stress plate 10 has the same structure as that shown in FIG. 3, in which a crystal plate 12 and a quartz glass plate 14 are linearly bonded. A pair of wide surfaces (shaded areas) of the crystal plate 12 are coated with electrode films by plating.
A quartz glass rod 42 is fixed to one side in the width direction of the crystal plate 12 with a silicone rubber adhesive 40 in a direction perpendicular to the longitudinal direction of the crystal plate 12, corresponding to the center point P of the crystal plate 12. . Similarly, quartz glass 1
A quartz glass rod 46 is fixed to one side in the width direction of the quartz glass plate 14 with a silicone rubber adhesive 44 in a direction perpendicular to the longitudinal direction of the quartz glass plate 14, corresponding to the center point Q of the quartz glass plate 14. . On the other hand, the bottom plate 48 has quartz glass rods 42 and 46.
The support grooves 50, 52 are arranged at intervals equal to the interval between
It is formed along the width direction of the bottom plate 48. The quartz glass rods 42, 46 are fitted into the support grooves 50, 52 with slight play. Further, a side plate 54 is screwed onto one side surface of the bottom plate 48 with a screw (not shown). This side plate 54 is formed with shallow stopper grooves 56 and 58 that communicate with the support grooves 50 and 52, respectively, and one ends of the quartz glass rods 42 and 46 are fitted into the stopper grooves 56 and 58, respectively, with a slight play. Ru. Similarly, a side plate 60 is screwed onto the other side of the bottom plate 48 with screws not shown. This side plate 60 also includes
Retaining grooves (not shown) corresponding to the support grooves 50 and 52 are formed, and quartz glass rods 42 and 46 are attached to these grooves.
The other end is inserted with slight play. The bottom plate 48 is screwed onto the 45-degree inclined surface of the triangular base 62 with screws (not shown). Also, stress plate 1
Near both ends in the longitudinal direction of the stress plate modulator, reflective plates 64 and 66 are arranged facing each other on a surface parallel to the paper surface of a case (not shown) that houses the stress plate modulator. In the stress plate modulator configured as described above, an alternating current voltage is applied to the electrode films adhered to the pair of wide surfaces of the crystal plate 12, and the crystal plate 12 is
2 to resonate and transmit a longitudinal wave to the quartz glass plate 14 to cause the quartz glass plate 14 to resonate and form a standing wave. Then, the phase difference between the two linearly polarized light components whose vibration directions are perpendicular to each other is periodically changed for the light that passes through the center point Q of the quartz glass plate 14 where the amplitude of distortion is maximum and is transmitted in the direction perpendicular to the plane of the paper. . On this occasion,
At the center point P of the crystal plate 12 and the center point Q of the quartz glass plate 14, the displacement in the longitudinal direction is always 0 (the amplitude of strain is maximum) with respect to longitudinal waves, as shown in FIG. The stress plate 10 is supported via silicone rubber adhesives 40 and 44 which are elastic bodies, and since the silicone rubber adhesives 40 and 44 are in surface contact with the stress plate 10, the silicone rubber adhesives 40 and 44 are in contact with each other. The protrusion 16 has a width of 44 as shown in FIG.
Contact diameter between ~22 and cylindrical rubber 30~36 is approximately 4mm
It can be made narrower, and can be supported in two places instead of four in the past, and the modulation characteristics can be stabilized for a longer period of time than in the past. In order to obtain the effects of the present invention, the width and thickness of the silicone rubber adhesives 40 and 44 are important, and preferably the width W is 2.0 to 3.0 mm and the thickness d is 0.3 to 0.7 mm. When width W = 2.5mm and thickness d = 0.5mm,
The initial characteristics of the stress plate 10 are superior to those in the conventional stress plate modulator shown in FIGS.
The longitudinal position change over time was about half that of the conventional stress plate modulator. That is, the stability over time of the stress plate modulator has been improved approximately twice, and the life span of the stress plate modulator has been approximately twice that of the conventional one.

[Effect of the idea]

As explained above, the stress plate modulator according to the present invention using a completely new support structure has the excellent effect of stabilizing the modulation characteristics over a long period of time. Moreover, since it is now possible to support an object at two places instead of four places in the past, there is also an excellent effect that the probability of product failure is lower than in the past.

[Brief explanation of drawings]

1 and 2 relate to an embodiment of the stress plate modulator according to the present invention, FIG. 1 is a front view of main parts of the stress plate modulator, and FIG.
The figure is an exploded perspective view of essential parts of the stress plate modulator. Figures 3 and 4 relate to conventional examples,
FIG. 3 is a partially vertical cross-sectional front view of the main part of the stress plate modulator, and FIG. 4 is a left side view of the main part of the stress plate modulator. FIG. 5 is a diagram showing the longitudinal displacement of the stress plate 10 with respect to longitudinal waves. In the figure, 10 is a stress plate, 12 is a crystal plate, 14 is a quartz glass plate, 40, 44 are silicone rubber adhesives, 42, 46 are quartz glass rods, 48 is a bottom plate, 50, 52 are support grooves, 56, 58 Stop groove, 54, 60 side plate, 62 triangular stand, 64, 6
6 is the reflector, P and Q are the center points.

Claims (1)

[Claims for Utility Model Registration] 1) One longitudinal end of a transparent second rectangular plate 14 is fixed to one longitudinal end of a first rectangular plate 12 that exhibits a piezo effect, and an alternating current voltage is applied to the first rectangular plate. A stress plate modulator that vibrates the first rectangular plate and transmits a longitudinal wave of the vibration to the second rectangular plate to modulate the light transmitted through the second rectangular plate. On one side in the width direction corresponding to the point P where the longitudinal displacement of the first rectangular plate 12 becomes 0,
The adhesive 40 becomes rubbery and has a thermal expansion coefficient of the first
A first rod member 42 that is substantially the same as the rectangular plate is bonded with its longitudinal direction perpendicular to the longitudinal direction of the first rectangular plate, so that the longitudinal displacement of the second rectangular plate 14 during the vibration is On one side in the width direction corresponding to point Q which is 0,
The adhesive 44 becomes rubbery and has a coefficient of thermal expansion of the second
A second bar member 46 that is substantially the same as the rectangular plate is glued with its longitudinal direction perpendicular to the longitudinal direction of the first rectangular plate, and a bottom plate 48 is attached corresponding to the first and second bar members.
By forming grooves 50 and 52 in the bottom plate, arranging the bottom plate so as to be inclined with respect to a horizontal plane, and fitting the first and second rod members into the grooves, the first and second rectangular plates are connected to each other. A stress plate modulator characterized by being supported on a bottom plate. 2) The adhesives 40 and 44 have a thickness of 0.3 to 0.7
2. The stress plate modulator according to claim 1, wherein the stress plate modulator has a width of 2.0 to 3.0 mm.