JP3516182B2 - Sealed fine movement device and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing type fine movement device mounted on an XY stage such as an optical fiber splicing device, a magnetic head processing dicing device, a semiconductor exposure device, and the like, and a manufacturing method thereof. Is.

[0002]

2. Description of the Related Art In recent years, with the advancement of optical communication, it is required that the positioning accuracy for joining the cores of optical fibers to each other is in the submicron range (1 μm or less).
In a conventional positioning device, the piezoelectric element has a structure in which the output member penetrates the tip cap, so the airtightness of the shaft sliding part is not perfect, and in the high-humidity environment for a long time, the entry of water vapor in the air is prevented. It is a structure that cannot be shut off.

On the other hand, in a precision positioning device having a structure in which a piezoelectric element is completely covered with a metal case, a part of the metal cylindrical body is made to have a spring property by a spatula process or the like in order to have a structure capable of expanding and contracting in the output shaft direction. However, when the piezoelectric element is incorporated in the metal container, there is a drawback that it is not possible to adjust the compression force (preload) to the piezoelectric element in advance. Further, since the output surface of the upper portion is directly bonded to the entire surface of the piezoelectric element, there is the following problem that the root of the cylindrical portion and the piezoelectric element itself are damaged or destroyed. (1) When the fine movement device is mounted on a stage to drive a heavy object or drive at high speed, a tensile force is applied to the output shaft, and the piezoelectric element receives the tensile force and is damaged. (2) When the tip of the output shaft and the stage are screwed together with a screw or the like, a rotational force is applied to the output shaft, and the piezoelectric element receives a bending force, so that the piezoelectric element is destroyed. (3) When a heavy object is placed and driven at high speed in the XY axis directions, a bending force that is not parallel to the output shaft is applied, and the piezoelectric element is damaged.

[0004]

The present invention has been made to solve the above problems, and the sealed type fine movement device of the present invention can be miniaturized as close as possible to the external dimensions of the piezoelectric element, and can be completely It has a sealed structure that can block water vapor in the air and is strong against the pulling force and bending force, which are the drawbacks of the piezoelectric element, and it has extremely high reliability and durability. Is to provide a method.

[0005]

The present invention is made of metal,
One end tubular cap having an end wall integrally or separately to; formed integrally on the other end of the cap, place-shaped outline disc spring
A disc spring having a constant of 50 to 150 kg / mm ; a piezoelectric element provided in the cap in pressure contact with one end in the axial direction of the cap; a closing member airtightly provided with the disc spring.
A conductive member which is airtightly pierced through a sealing body composed of the closing member and the cap to communicate with the piezoelectric element;
Is characterized by. The disc spring portion of the present invention is characterized by having a bulging portion that bulges outward in cross section . The piezoelectric element according to the present invention is arranged via a receiving member having a concave receiving portion between the sealing body and a substantially hemispherical rotating member having a spherical surface accommodated in the receiving portion. Features
It

According to the present invention, a cylindrical cap made of metal and having one end or a separate end wall at one end is provided with a rough disc spring at the other end.
Disc spring portions shaped for spring constant 50 to 150 kg / mm is formed,
A piezoelectric element having a conductive member connected to an external conductive member is housed in the cap, a closing member is positioned corresponding to the spring portion, and force is applied from the outside in the axial direction composed of the closing member and the one end. It was added, wherein the piezoelectric element is pressurized, fixed or fixed airtightly closure member and the spring portion, the conductive member to the outside of the sealing body consisting of the closure member and the cap, be in communication in an airtight And The fixing of the present invention is characterized by being welding. The fixation of this invention is
A packing member is interposed between the closing member and the spring portion, and a screw is used.

[0007]

According to the present invention, as described above, the sealing body is provided with the cylindrical cap airtightly provided on the closing member via the disc spring portion, and the piezoelectric element is provided on the end wall at one end in the axial direction of the cap. Since the disc spring can support a large load in such a manner that it does not take up a space in the load direction, it is possible to form the device of the present invention in a compact size and to provide the piezoelectric element. It can withstand strong and long-term vibrations caused by Further, when the disc-shaped spring portion is provided with a flange-shaped fixing or fixing margin on the outer periphery thereof, it can be formed at an angle at which the elastic fatigue of the spring is very small. It is easy to fix and fix to the spring and fatigue of the spring due to its shape can be minimized.
Also, if the material of the disc spring portion is selected according to its shape, the spring constant suitable for vibration of the piezoelectric element is 50 to 150 kg / mm.
Can be easily formed. Further, the disc spring portion provided with the bulging portion in its cross section can provide a relatively soft spring, and therefore can favorably follow the high-speed vibration of the piezoelectric element. In addition, a spring having a plurality of bulged portions can provide a softer spring and can follow the above in a better manner. In addition, the piezoelectric element
When a receiving member having a concave receiving portion and a rotating member having a substantially hemispherical shape that accommodates a spherical surface in the receiving portion are provided between the sealing body and the sealing member, a pulling force is applied to the cap. Even if applied, the rotating member and the receiving member are separated from each other, so that damage to the piezoelectric element can be prevented. Further, even if a bending force that is not parallel to the axial direction is applied to the cap, the rotating member rotates and the bending force is not directly transmitted to the piezoelectric element, so that damage to the piezoelectric element can be prevented. Further, since this device has the spring constant as described above, by changing the shape and thickness of the cap, it is possible to select a predetermined value within the force of the piezoelectric element within the range of the constant, and thereby the mechanical resonance frequency. A high-speed response close to is possible. Further, the cap and the sealing body can be completely shielded from water vapor, dust, etc. in the air by welding or fixing them with a screw via a packing material. Further, regarding the method of manufacturing this device, the spring part of the cap accommodating the piezoelectric element and the closing member are brought into contact with each other, and pressure is applied from the outside to fix the closing member and the cap part in the state where the piezoelectric element is pressed. Since it is fixed, the piezoelectric element can be sealed very easily by applying a preload to it at one time. Further, in this case, since the disc spring portion is bent flexibly by providing the bulging portion, the manufacturing in the case of the fixing and fixing is easy. Further, since the fixing by welding is performed by the margin of the outer periphery of the disc spring portion, the influence of welding distortion on elasticity can be eliminated.

[0008]

Embodiment 1 The device of the present invention is made of metal, as shown in FIG.
For example, the piezoelectric element 4 is housed in a sealing body 3 (cylindrical body) which is made of a stainless steel cap 1 and a mounting flange as the closing member 2, and the cap 1 and the closing member 2 are sealed by electric welding. It has been stopped. The piezoelectric element 4 is a laminated type piezoelectric element having a structure in which positive and negative internal electrodes are alternately laminated, the piezoelectric ceramics and the electrodes are integrally fired, and external electrodes are connected to the end faces of the piezoelectric element.
V / mm) was used. Shape 5
When a voltage of 140 V is applied using the piezoelectric element 4 of (L) × 7 (W) × 10 (H) mm, the piezoelectric element 4 overcomes the preload and extends by about 10 μm, pushing up the upper plate 5. .

A hemispherical rotating member 7 is provided at the center of the closing member 2.
And a receiving member 9 having an inverted spherical (not shown) or V-shaped receiving portion 8 is formed on the lower plate 6 facing each other. A high hardness material is used for the rotating member 7 and the receiving member 9. In addition, 11 is a bulge, 12 is a conductive member, 13 is a cover, and 14 is a tap hole. The spring constant of the disc spring portion 10 of the cap 1 is set to 100 kg / mm by setting the shape and thickness as shown in FIG. 1, and the preload is 100 kgf.
Adjusted to. The shape and thickness of the disc spring portion 10 can be empirically selected by the following empirical formula.

[Equation 1] Here, the value of the deflection coefficient α is determined by the ratio of the inner and outer radii (b / a).

[Equation 2] Further, the composite spring constant k when the bulging portion 11 has multiple steps such as two steps, three steps, etc., the spring constant of the first step is k1, the spring constant of the second step is k2, and the spring constant of the third step is If k3 ..., It is expressed as follows.

[Equation 3] The voltage applied to the piezoelectric element 4 is provided by providing a current introducing terminal as the conductive member 12 covered with insulating glass on the surface of the mounting flange as the closing member 2, and the current introducing terminal is glass-welded to the mounting flange. The current introducing terminal inside the mounting flange is soldered to the plus and minus lead wires of the piezoelectric element 4 and covered with a heat shrinkable tube. The current-introducing terminal portion on the outside of the mounting flange was filled with a water-repellent resin and covered with a coating to prevent dew condensation in a high humidity environment.

Next, as an application of this embodiment, FIG. 5 shows an example of operating a piezoelectric switch which is driven at a high speed with a light load. A voltage is applied to the fine movement device 22 of the present invention to make it expand and contract, and the amount of expansion and contraction of the arm 2 using the lever principle.
Then, the movable contact 24 is brought into contact with the fixed contact 25 by amplifying it by 3. In addition, 26 is a frame and 27 is a lead wire.
In this device, the preload is adjusted to 100 kgf, and a rectangular wave is repeatedly applied to the piezoelectric element up to the maximum voltage (140 V) to turn the piezoelectric switch on and off. The higher the spring constant is, the better the followability of high-speed driving is. However, when the force exceeds the generated force determined by the cross-sectional area of the piezoelectric element 4, the extension is hindered. When the spring constant is 100 kg / mm, high-speed response of 1 to 10 msec is possible. Also, after applying a voltage to extend the piezoelectric element 4 and then returning the voltage to zero, the piezoelectric element 4 tries to return to its original length, and at that moment, a force greater than the tensile breaking force is applied to the piezoelectric element 4. Since a preload is applied to the
Destruction can be prevented.

[0011]

[Embodiment 2] As shown in FIG. 3, the present apparatus has a piezoelectric element in a sealing body 3 composed of a stainless steel cap 1 and a closing member 2 in which an output member 16 and a mounting portion 17 are previously welded by electron beam welding. There is an element block 18 in which the element 4 is housed, and the cap 1 and the closing member 2 are joined together by sealing with a screw 20 via a packing member 19 such as an O-ring or a metal. The piezoelectric element 4 uses a laminated piezoelectric element having a structure in which positive and negative internal voltages are alternately laminated, the piezoelectric ceramics and electrodes are integrally fired, and external electrodes are connected to the end surface of the piezoelectric element 4, and a high DC voltage (2 KV / Mm) which was polarized. Shape is 5 (L) x 7
Using the (W) × 40 (H) mm piezoelectric element 4, 14
When a voltage of 0 V is applied, the piezoelectric element 4 overcomes the preload and extends by about 40 μm, pushing up the upper plate 5.
A rotating member 7 is fixed to the center of the lower plate 6, and a receiving member 9 having an inverted spherical or V-shaped receiving portion 8 is provided at the position of the closing member 2 which faces the lower plate 6. The rotating member 7 and the receiving member 9 are made of a high hardness material to prevent deformation and wear. The spring constant of the disc spring portion 10 of the cap 1 is set to 50 kg / mm by selecting the shape and thickness as shown in FIG. 3, and the preload is set to 50 kgf by tightening the screw 20 of the closing member 2.
Adjusted to. The voltage applied to the piezoelectric element 4 is provided by providing a current introducing terminal covered with insulating glass on the surface of the closing member 2, and the current introducing terminal is sealed with the closing member 2 by glass fusion. The current introducing terminal inside the closing member 2 is soldered to the plus and minus lead wires of the piezoelectric element 4 and covered with a heat shrinkable tube. The current-introducing terminal portion on the outside of the mounting flange was filled with a water-repellent resin and covered with a coating to prevent dew condensation in a high humidity environment.

As an application of this embodiment, FIG. 6 shows an example of operating an XY stage which is driven at low speed intermittently under a heavy load. The coarse movement stage 30 is moved by the DC servo motor 29 for X-axis / Y-axis movement to roughly adjust the position, and
A fine movement stage 31 is provided by the fine movement device 22 installed for the Y axis.
Move to adjust the stage to the desired position. 32
Is a Y-direction drive frame, 33 is a fixed plate, 34 is an XY slide surface, and 35 is a flexible support rod.

This device is adjusted to have a spring constant of 50 kg / mm and a preload of 50 kgf, and is directly screwed at the tip of the output shaft. Several hundred ms up to the maximum voltage (140v) on the piezoelectric element
This is an example in which ultra-precision positioning in which a voltage is linearly applied over a period of ec is performed intermittently (several seconds) simultaneously with the XY axes. Since the piezoelectric element 4 is prevented from expanding when a preload exceeding a generated force determined by the cross-sectional area is applied, it is necessary to set the preload below the generated force of the used piezoelectric element. FIG. 7 shows the degree to which the amount of displacement of the piezoelectric element is obstructed by the compressive force. Efficiency =
The amount of displacement after compression / the amount of displacement without load × 100. In the case of a piezoelectric element with a shape of 5 (L) x 7 (W) x 10 (H) mm, the efficiency is 100% up to a compression force of 200 kgf.
The same displacement as when no load is applied. It can be seen from FIG. 7 that the efficiency decreases when the compression force exceeds 200 kgf. FIG. 8 is a diagram in which a durability test was performed with a tensile force intentionally applied. A piezoelectric element 4 having a shape of 5 (L) x 7 (W) x 40 (H) is used, and the piezoelectric element 4 is connected by a weight and a screw that are formed so as to surround the periphery of the device by using a tap at the tip of the device, Arranged in the displacement direction of the element 4, under room temperature and 90% humidity environment,
The test was conducted 10 ⁸ times at a voltage of 0 to 140 V at a sine wave of 40 Hz. The heavier the weight attached, the stronger the tensile force.

Further, when a voltage is applied to extend the piezoelectric element 4 and then the voltage is set to zero, the piezoelectric element 4 tries to return to its original length, and a strong tensile force is applied to the piezoelectric element 4, but the piezoelectric element 4 breaks in the range of preload. When the pulling force exceeding the preload is applied, the rotating member 7 is momentarily disengaged and does not break. When the X and Y axes are simultaneously driven, a bending force is applied to the device, but the rotating member 7 rotates and the force is not transmitted directly to the piezoelectric element. FIG. 9 shows the damage failure after the tensile durability test of FIG. As is apparent from FIG. 9, in the device E of the present invention, defective products do not occur even 10 ⁸ times, whereas in the device e of the conventional example, defective products start to be generated 10 ⁴ times.
After 10 ⁸ times, the defective rate is 45%. As described above, the device E of the present invention can significantly reduce the defect rate as compared with the device e of the conventional example.

[0015]

The present invention is constructed as described above, and the sealing body is provided with a cylindrical cap airtightly provided on the closing member via the disc spring part, and the piezoelectric element is provided with one end of the cap in the axial direction. Since the disc spring can support a large load so as not to take up a space in the load direction as a characteristic of the disc spring, the device of the present invention can be formed in a small size because of its pressure contact with the wall. It can withstand the strong and long-term vibration caused by the piezoelectric element and can be operated. Further, when the disc spring portion is provided with a flange-shaped fixing or fixing margin on the outer periphery thereof, it can be formed at an angle at which the elastic fatigue of the spring is extremely small. Therefore, the disc spring is closed by using the above margin while applying pressure to the piezoelectric element. It can be easily fixed and fixed to the member, and fatigue of the spring due to its shape can be minimized. If the material of the disc spring portion is selected according to its shape, a spring constant of 50 to 150 suitable for vibration of the piezoelectric element is obtained.
It can be easily formed to kg / mm. Further, the disc spring portion provided with the bulging portion in its cross section can provide a relatively soft spring, and therefore can favorably follow the high-speed vibration of the piezoelectric element. In addition, a spring having a plurality of bulged portions can provide a softer spring and can follow the above in a better manner. Further, the piezoelectric element is disposed between the sealing member and the sealing member via a receiving member having a concave receiving portion, and a substantially hemispherical rotating member having a spherical surface accommodated in the receiving portion. Even if a pulling force is applied to the cap, the rotating member and the receiving member are separated from each other,
It is possible to prevent damage to the piezoelectric element. Even if a bending force that is not parallel to the axial direction is applied to the cap, the rotating member rotates,
Since the bending force is not directly transmitted to the piezoelectric element, damage to the piezoelectric element can be prevented. Further, since this device has the spring constant as described above, by changing the shape and thickness of the cap, it is possible to select a predetermined value within the force of the piezoelectric element within the range of the constant, and thereby the mechanical resonance frequency. A high-speed response close to is possible. Further, the cap and the sealing body can be completely shielded from water vapor, dust, etc. in the air by welding or fixing them with a screw via a packing material. Further, regarding the method of manufacturing this device, the spring part of the cap accommodating the piezoelectric element and the closing member are brought into contact with each other, and pressure is applied from the outside to fix the closing member and the cap part in the state where the piezoelectric element is pressed. Since it is fixed, the piezoelectric element can be sealed very easily by applying a preload to it at one time. Further, in this case, since the disc spring portion is bent flexibly by providing the bulging portion, the manufacturing in the case of the fixing and fixing is easy. Further, since the fixing by welding is performed by the margin of the outer periphery of the disc spring portion, the influence of welding distortion on elasticity can be eliminated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a sealed type fine movement device according to an embodiment of the present invention.

2 is a bottom view of the device shown in FIG. 1. FIG.

FIG. 3 shows a second embodiment of the present invention and corresponds to FIG.

FIG. 4 is a bottom view of the device shown in FIG.

FIG. 5 is a diagram illustrating a piezoelectric switch that is an application example of the first embodiment.

FIG. 6 is a diagram illustrating an XY stage that is an application example of the second embodiment.

FIG. 7 is a diagram showing a relationship between a compression force and a displacement amount of a piezoelectric element.

FIG. 8 is a diagram showing a durability test method in which a tensile force is intentionally applied using the apparatus of the present invention.

FIG. 9 is a diagram showing a failure defect rate by the tensile test of FIG.

[Explanation of symbols]

1 cap 2 Closing member 3 sealed body 4 Piezoelectric element 5 Upper plate 6 Lower plate 7 Rotating member 8 Receiver 9 Receiving member 10 Disc spring part 11 bulge 12 Conductive member 13 Lead wire take-out groove 14 tap holes 16 Output member 17 Mounting part 18 element block 19 Packing member 20 screw

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-165683 (JP, A) Actually open 3-106884 (JP, U) Actually open 64-39664 (JP, U) Actually open 3- 63957 (JP, U) Japanese Patent Publication 6-28832 (JP, B2) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02N 2/00 G05D 3/00 G12B 5/00 H01L 41/08

Claims (6)

(57) [Claims] 1. A cylindrical cap made of metal and having one end or a separate end wall at one end; a roughly disc spring-like spring constant integrally formed at the other end of the cap having a spring constant of 50 to 150 kg / mm
Disc spring portion of; sealing consisting of the closed locking member and said cap; closure member provided on the disc spring portion and airtightly; in the cap, the piezoelectric element provided in pressure contact with the axial end of said cap A hermetically sealed fine movement device comprising: a conductive member that penetrates a body in an airtight manner and communicates with the piezoelectric element. 2. The sealed fine movement device according to claim 1, wherein the disc spring portion has a bulging portion that bulges outward in a cross section. 3. The piezoelectric element has a concave shape between it and the sealing body.
A receiving member having a hook portion, and a spherical surface accommodated in the receiving portion.
A substantially hemispherical rotating member is disposed through the rotating member.
The sealed type fine movement device according to 1 or 2. 4. An end wall which is made of metal and has one end or a separate end wall.
The other end of the cylindrical cap has a spring constant of 50 to 150.
forming a disc spring part having a roughly disc spring shape of kg / mm ,
Piezoelectric element having conductive member connected to external conductive member
Position the closing member to accommodate the child and to correspond to the spring part.
And the axial outside composed of the closing member and the one end.
Is applied to pressurize the piezoelectric element,
The closing member is airtightly fixed or fixed, and the conductive member is
It is airtightly connected to the outside of the sealing body consisting of the closure member and the cap.
Method for producing a sealing fine movement device characterized by causing threaded. 5. The method for manufacturing a hermetically sealed fine movement device according to claim 4 , wherein the fixing is welding . 6. A packing is fixed between the closing member and the spring portion.
The method according to claim 4 or 5, which is performed by a screw through a connecting member.
A method for manufacturing the sealed type fine movement device.