JPH10118874A - Minute interval driving mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple, quick response, accurate and high rigidity minute interval driving mechanism which can be manufactured with ease. SOLUTION: Each one of piezoelectric elements 13a to 13d is arranged at each of four corners between a fixed platen 11 with a datum face 11a and an intermediate moving platen 12, constituting a first drive mechanism 10A, and each one of piezoelectric elements 15a to 15d is arranged at each of four corners between the intermediate moving platen 12 and a moving platen 14, constituting a second drive mechanism 10B, providing a strong two-storied structure. The three dimensional driving and positioning of the moving platen 14 become possible by superposing the driving and positioning in a plane parallel with the datum face 11a by inclining the intermediate platen 12 by extending and contracting each piezoelectric element of the first drive mechanism 10A and correcting the inclination of the moving platen by extending and contracting each piezoelectric element of the second drive mechanism 10B, and the three dimensional on the driving and positioning in the direction orthogonal to the datum face 11a by equally extending and contracting two sets of four piezoelectric elements of each driving mechanism simultaneously or only one set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a minute distance driving mechanism of a two-dimensional or three-dimensional positioning device used as a precision positioning table of a precision processing device, a semiconductor manufacturing device, or the like.

[0002]

2. Description of the Related Art Conventionally, there is a known technique shown in FIG. In this apparatus, an X-axis actuator 4, a Y-axis actuator 3, and a Z-axis actuator 2 made of a piezoelectric element or a magnetostrictive element are incorporated in a guide frame 1 in which a parallel spring element is formed by cutting out an elastic body. By transmitting a signal according to the purpose to each of 3 and 4, and expanding and contracting, a portion of 7 in the X-axis direction, a portion of 6 in the Y-axis direction, and a portion of 5 in the Z-axis direction are used as parallel springs and serve as distortion standards. Moving end 1b with respect to fixed end 1a
Is displaced.

[0003]

According to the known technique shown in FIG. 5 which is described in the prior art, the shape of the guide frame 1 is complicated and difficult to process. Therefore, there is a problem that the rigidity tends to be insufficient. SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and has as its object to provide a minute distance driving mechanism which is easy to manufacture and has high rigidity.

[0004]

In order to achieve the above object, a minute distance driving mechanism according to the present invention is disposed between a fixed base having a reference surface and an intermediate movable base with a telescopic axis at right angles. At least three minutely extendable first drive members;
At least three minutely expandable and contractible second drive members disposed between the intermediate movable table and the movable table with a telescopic axis at right angles, and the first and second drive members are synchronized with each other. A driving control means for controlling the first and second driving members to simultaneously extend and contract, respectively, to tilt the intermediate moving table, and to tilt the moving table so as to compensate for the inclination, thereby driving in a direction parallel to the reference plane.・ Positioning and driving in the direction perpendicular to the reference plane by simultaneously expanding and contracting all the driving members or the first driving member or the second driving member by the same amount. This enables positioning. In addition, the first driving member and the second
The driving member is a piezoelectric element. The first driving member and the second driving member are magnetostrictive elements.

According to the micro-distance driving mechanism configured as described above, the first driving member and the second driving member, for example, the first piezoelectric element and the second piezoelectric element are driven synchronously, so that The movable table can be arbitrarily driven at high speed and accurately in a three-dimensional direction in a plane parallel to the reference plane and in a direction perpendicular to the reference plane within a simple range. It has the advantage of low production costs.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to a perspective view of a minute distance driving mechanism shown in FIG. 1, a sectional view shown in FIG. 2, an operation explanatory view of driving positioning control shown in FIG. A description will be given based on the diagram. In all the drawings, the cover of the minute distance driving mechanism is omitted.

Referring to FIG. 1, a small distance driving mechanism 10 of the present invention has a plurality of fixed bases 11 each having a substantially square shape having a reference surface 11a, and a plurality of intermediate movable bases 12 having the same shape at four corners. In this embodiment, four first driving members 13a,
13b, 13c, and 13d are disposed with their telescopic axes at right angles to the reference surface 11a of the fixed base 11, and the fixed base 11 and the intermediate movable base 12 are provided with four first driving members 13 respectively.
A first driving mechanism 10A having rigidity is firmly connected vertically through a, 13B, 13c, and 13d.

Further, four second driving members 15 are also provided at four corners between the intermediate movable table 12 and the movable table 14 having the same shape.
a, 15b, 15c, 15d are the first driving members 13a, 1
Similarly to 3b, 13c and 13d, the telescopic axes are respectively arranged at right angles to the reference plane 11a, and the intermediate movable table 12 and the movable table 14 are connected to the second driving members 15a, 15b, 1
5c, 15d and a rigid second
The drive mechanism 10B is configured adjacent to the first drive mechanism 10A.

The first driving members 13a, 13b, 13c, 1
3d and second drive members 15a, 15b, 15c, 15d
A device capable of controlling expansion and contraction in the axial direction is used. For example, a known driving element such as a piezoelectric element or a magnetostrictive element can be used. The piezoelectric element is a ceramic block made of a material such as a barium titanate crystal, and has a structure in which a plurality of unit elements in which the directions of distortion due to the piezo effect are aligned in the axial direction are stacked via an electrode plate.

When an operation voltage based on a drive signal is applied to each electrode plate by a drive control device 20, which will be described later, the axial length of the entire piezoelectric element can be accurately controlled according to the voltage, and the responsiveness is improved. Responsiveness (several hundred hertz to several kilohertz) and rigidity higher by one digit or more can be obtained as compared with a conventional servo mechanism using a ball screw or the like.

The magnetostrictive element utilizes a magnetostrictive property in which a magnetic substance is slightly deformed when magnetized, and is applied to the element in the same manner as a piezoelectric element expands and contracts according to a voltage applied to the element. It expands and contracts according to the strength of the applied magnetic field, and controls the expansion and contraction by controlling the current flowing through the coil wound around the element. Thereby, the same effect as that of the piezoelectric element can be obtained.

Next, the principle of drive / positioning control of the minute distance drive mechanism 10 of the present invention will be described with reference to cross-sectional views on the XZ plane of FIGS. First, the drive / positioning control of the moving table 14 in the X direction will be described. As shown in FIG. 3, four driving elements of the first driving mechanism 10A, for example, two right-side piezoelectric elements 13a and 13b of the piezoelectric element are extended by αL ₁ and two left-side elements 13c and 13d are reduced by αL ₁ . . As a result, the intermediate moving body 12 becomes α around the point P1.
The movable table 14 of the second drive mechanism 10B is inclined by the angle θ in the illustrated direction (downward to the right).

Therefore, at the same time, the second drive mechanism 10B
Out of the four piezoelectric elements 15a, 15b on the right
It was reduced by L _2, the left two 15c, to extend the 15d only .alpha.L _2. In this way, the inclination of the movable base 14 indicated by the imaginary line is corrected, and the surface 14a of the movable base 14 is parallel to the X axis, that is, parallel to the reference plane 11a.

[0014] reference point P2 in this case the moving table 14 is positioned at a position displaced by the X-axis direction moving length L _X. The movement length L _X can be obtained by the following expression 1. L _X = L ₂ · αθ (1) where L ₂ = P ₁ and P ₂ .

The piezoelectric element 15 of the second drive mechanism 10B
a, 15b and 15c, telescopic length .alpha.L ₂ of 15d are the following 2
It can be obtained from the relationship between the expressions. _{αθ = 2 · αL 1 / D} = 2 · αL 2 / D 2 ······ 2 expression, however, .alpha.L ₁ = piezoelectric element 13a of the first drive mechanism 10A,
13b, 13c, and 13d, the length of expansion and contraction, D ₁ = the distance between the axes of the piezoelectric elements of the first drive mechanism 10A, and D ₂ = the second drive mechanism 1
0B is the distance between the axes of the piezoelectric element.

Although the drive and positioning control in the X direction has been described above, the drive and positioning control in the Y axis direction is almost the same, and can be realized by changing the combination of expansion and contraction of each piezoelectric element. Specifically, one of the piezoelectric elements of the first drive mechanism 10A
Combinations of 3a and 13b are represented by 13a, 13c, 13c and 13
d is 13b, 13d, and the second drive mechanism 10B
The combination of the piezoelectric elements 15a and 15b
The combination of c, 15c and 15d may be 15b and 15d. Further, a first driving mechanism 10A, a second driving mechanism 10B
If one set of piezoelectric elements is expanded and contracted in the same direction by the same amount in two or one set at a time, positioning in the Z-axis direction is possible.

Therefore, the above-described movement amounts in the X, Y, and Z directions are weighted, and the control voltage is applied to each of the piezoelectric elements by the drive control device 20 described later as a command value with the obtained expansion and contraction amount of each of the piezoelectric elements. Then, the reference position P ₂ can be freely driven and positioned at any position within the operation range of the minute distance driving mechanism 10.

FIG. 4 shows a drive control device 20 for controlling expansion and contraction of each piezoelectric element of the first drive mechanism 10A and the second drive mechanism 10B.
FIG. The movement amount input unit 21 inputs a target minute movement amount in the X, Y, and Z directions, and the expansion and contraction amount calculation unit 22 of each piezoelectric element calculates the expansion and contraction amount of each piezoelectric element from the input movement amount. L) calculation part, L / E
The conversion unit 23 converts the obtained expansion / contraction amount (L) of each piezoelectric element into a voltage amount (E) for realizing this. The supply voltage output unit 24 is based on a signal from the L / E conversion unit 23. This is a portion for outputting a DC voltage to each piezoelectric element of the minute distance drive mechanism 10.

Therefore, if the target movement amount in the X, Y, and Z directions is input by using the above-described drive control device 20, each piezoelectric element automatically expands and contracts, and
4a can be driven and positioned at a target movement position.

[0020]

Since the minute distance mechanism of the present invention is constituted as described above, the following effects are obtained. Since the fixed base and the intermediate base with the reference plane, and the two-stage drive structure in which the intermediate base and the mobile base are connected by the piezoelectric element or the magnetostrictive element, the structure is simple and the manufacturing is easy and the failure is small, An accurate, high-rigidity, high-response minute distance drive mechanism can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a minute distance driving mechanism of the present invention.

FIG. 2 is a cross-sectional view on the X, Y, and Z planes of the minute distance driving mechanism of the present invention.

FIG. 3 is a cross-sectional view for explaining the operation of the minute distance driving mechanism according to the present invention on the X, Y, and Z planes.

FIG. 4 is a block diagram of a drive control device.

FIG. 5 is a cross-sectional view of a conventional minute distance driving mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Micro-distance drive mechanism 10A 1st drive mechanism 10B 2nd drive mechanism 11 Fixed base 11a Reference surface 12 Intermediate movable base 13a-13d Piezoelectric element of first drive mechanism 14 Mobile base 14a Surface 15a-15d Piezoelectric element of second drive mechanism

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 41/12 H01L 41/08 C

Claims (3)

[Claims] 1. An at least three telescopic shaft disposed between a fixed base having a reference surface and an intermediate movable base with a telescopic axis at a right angle.
A plurality of first minutely extendable first drive members, at least three minutely extendable second drive members disposed between the intermediate movable table and the movable table with an extendable axis perpendicular to the first movable member; Drive control means for controlling the drive member and the second drive member in synchronization with each other, allowing the first and second drive members to expand and contract to enable driving and positioning of the movable table in an arbitrary three-dimensional direction. A minute distance driving mechanism. 2. The minute distance driving mechanism according to claim 1, wherein the first driving member and the second driving member are piezoelectric elements. 3. The minute distance driving mechanism according to claim 1, wherein the first driving member and the second driving member are magnetostrictive elements.