JP2008048551A - Two-dimensional shifter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric element vibrator which moves a driven body in a two-dimensional direction without complicating circuit constitution. <P>SOLUTION: The piezoelectric element vibrator includes a shim having an outer wall, and a piezoelectric device fixed to the shim in a third direction which is perpendicular to a first direction and a second direction, wherein the first direction is perpendicular to the outer wall, and the second direction is perpendicular to the outer wall and the first direction. A first to a fourth electrodes are fitted on the piezoelectric device which are lined in order and arranged in a circumferential direction. A first AC voltage is applied to the first electrode, a second AC voltage is applied to the second electrode, a third AC voltage is applied to the third electrode, and a fourth AC voltage is applied to the fourth electrode. When a first energizing member which energizes the outer wall in the second direction is moved to one side of the first direction, the first AC voltage is applied; and when it is moved to the other side of the first direction, the third AC voltage is applied. When a second energizing member which energizes the outer wall in the first direction is moved to one side of the second direction, the second AC voltage is applied; and when it is moved to the other side of the second direction, the fourth AC voltage is applied. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drive device, and more particularly to a drive device that moves a driven body in an arbitrary two-dimensional direction.

There has been proposed a moving device that moves a driven body in a two-dimensional arbitrary direction using a piezoelectric vibrator. Patent Document 1 discloses a two-dimensional moving device in which a piezoelectric vibrator is pressurized in a direction perpendicular to a moving plane.
JP 2004-274898 A

  However, since the apparatus of Patent Document 1 performs movement control by applying voltage to all four pairs (or five pairs) of electrodes, the circuit configuration becomes complicated.

  Accordingly, an object of the present invention is to provide a piezoelectric vibrator and a two-dimensional movement device that translate (move) a driven body in a two-dimensional direction without complicating a circuit configuration.

  The piezoelectric vibrator according to the present invention is shims in a third direction perpendicular to both a shim having an outer wall portion and a first direction perpendicular to the outer wall portion and a second direction perpendicular to the outer wall portion and the first direction. The first to fourth electrodes arranged in order in the circumferential direction on a plane perpendicular to the third direction are attached to the piezoelectric element, and the first AC is connected to the first electrode. A voltage is applied, a second AC voltage is applied to the second electrode, a third AC voltage is applied to the third electrode, a fourth AC voltage is applied to the fourth electrode, and the outer wall is biased in the second direction. When the first urging member to be moved is moved in one direction in the first direction, either one of the first and third AC voltages is applied, and the second urging force is applied to the outer wall portion in the first direction. When moving the biasing member in one of the second directions, one of the second and fourth AC voltages is applied, and the first attachment When the member is moved in the other direction of the first direction, either one of the first and third AC voltages is applied, and when the second biasing member is moved in the other direction of the second direction, One of the second and fourth AC voltages is applied.

  Preferably, the first electrode and the third electrode are arranged in the first direction, and the second electrode and the fourth electrode are arranged in the second direction.

  Preferably, the first AC voltage is adjusted based on the strain amount of the third electrode, the second AC voltage is adjusted based on the strain amount of the fourth electrode, and the third AC voltage is the first electrode. The fourth AC voltage is adjusted based on the amount of distortion of the second electrode.

  Preferably, the longitudinal vibration in the radial direction of the piezoelectric vibrator and the lateral vibration in the first direction of the piezoelectric vibrator are excited by the application of the first AC voltage, and the longitudinal vibration in the first direction of the piezoelectric vibrator is applied by the application of the second AC voltage. The vibration and the transverse vibration in the second direction of the piezoelectric vibrator are excited, the longitudinal vibration and the transverse vibration in the first direction are excited by the application of the third alternating voltage, and the application of the fourth alternating voltage, Longitudinal vibration and lateral vibration in the second direction are excited.

  More preferably, the drive frequency of the first to fourth AC voltages is set to a value between the resonance frequency of the longitudinal vibration and the resonance frequency of the lateral vibration in the first and second directions.

  The two-dimensional movement device according to the present invention is configured to shim in a third direction perpendicular to both a shim having an outer wall portion and a first direction perpendicular to the outer wall portion and a second direction perpendicular to the outer wall portion and the first direction. A fixed portion having a piezoelectric vibrator having a piezoelectric element to which first to fourth electrodes are attached, which are fixedly arranged in order in a circumferential direction on a plane perpendicular to the third direction, and in contact with the outer wall portion Applying a first AC voltage to the first electrode, a vertical direction moving part that urges the outer wall part in the first direction, a horizontal direction moving part that contacts the outer wall part and urges the outer wall part in the second direction, A second AC voltage is applied to the second electrode, a third AC voltage is applied to the third electrode, and a fourth AC voltage is applied to the fourth electrode. Based on the voltage application of one of the third AC voltages, the horizontal direction moving part is moved to one side in the first direction, and the second and fourth AC Based on the voltage application of one of the voltages, the vertical movement unit is moved in one of the second directions, and based on the voltage application of the other one of the first and third AC voltages, the horizontal movement unit is moved to the first. It moves to the other of 1 direction, and a vertical direction moving part is moved to the other of the 2nd direction based on the voltage application of the other of a 2nd, 4th alternating voltage.

  Preferably, the vertical movement unit moves in the second direction in conjunction with the movement in the second direction, the vertical movement unit is slidably supported in the first direction, and the horizontal movement unit moves in the first direction. It moves in the first direction in conjunction with the load table, and has a loading platform that supports the horizontal movement unit slidably in the second direction and a piezoelectric vibrator, and the vertical movement unit can slide in the second direction. And a fixed portion that slidably supports the horizontal direction moving portion in the first direction.

  Preferably, in the circuit unit, when the third AC voltage is applied to the third electrode, the first detection unit that detects the distortion amount of the first electrode and the fourth AC voltage is applied to the fourth electrode. Sometimes, a second detector that detects the amount of distortion of the second electrode, a third detector that detects the amount of distortion of the third electrode when a first AC voltage is applied to the first electrode, and a second electrode When the second AC voltage is applied, the control unit includes a fourth detection unit that detects a distortion amount of the fourth electrode, and the control unit detects the first AC voltage detected by the third detection unit. Adjusting the second AC voltage based on the amount of distortion detected by the fourth detector, adjusting the third AC voltage based on the amount of distortion detected by the first detector, 4 AC voltage is adjusted based on the distortion amount detected by the 2nd detection part.

  More preferably, when the third AC voltage is applied to the third electrode, the circuit unit applies the fourth AC voltage to the first switch that connects the first electrode and the first detection unit and the fourth electrode. Sometimes, a second switch that connects the second electrode and the second detector, a third switch that connects the third electrode and the third detector when a first AC voltage is applied to the first electrode, and a second switch A fourth switch is provided for connecting the fourth electrode and the fourth detector when the second AC voltage is applied to the electrode.

  Preferably, the adjustment of the first to fourth AC voltages is performed by time-sharing control that adjusts the time width for applying the first to fourth AC voltages.

  As described above, according to the present invention, it is possible to provide a piezoelectric vibrator and a two-dimensional movement device that translate (move) a driven body in a two-dimensional direction without complicating the circuit configuration.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The two-dimensional moving device 1 includes a movable unit having a horizontal moving unit 10, a vertical moving unit 20, and a loading table 40, and a fixed unit having a piezoelectric vibrator 30, a fixed table 50, and a circuit unit 70. Prepare. In order to describe the direction, in the two-dimensional moving device 1, the moving direction of the horizontal moving unit 10 is the first direction x, the moving direction of the vertical moving unit 20 orthogonal to the first direction x is the second direction y, A direction orthogonal to the first direction x and the second direction y will be described as a third direction z.

  The horizontal movement unit 10 includes first and second friction members 11 and 12, a first engagement unit 15, a second engagement unit 16, first and second protrusions 18 a and 18 b, and a horizontal movement frame 19. Have The horizontal direction moving part 10 can move in the first direction x, and when moving, the loading table 40 also moves in the first direction x in conjunction with it.

  The first and second friction members 11 and 12 have a rectangular parallelepiped shape, and one of the planes perpendicular to the second direction y is in contact with the piezoelectric vibrator 30, and the horizontal moving frame 19 is caused by the vibration of the piezoelectric vibrator 30. At the same time, it is movable in the first direction x, and the other is attached inside the horizontal movement frame 19.

  The first engaging portion 15 has two elongated holes extending in the second direction y, and the two protrusions of the first protruding portion 41 of the loading table 40 are slidably engaged in the second direction y. (See FIG. 1). Thereby, when the loading platform 40 moves in the second direction y as the vertical movement unit 20 moves in the second direction y, the horizontal movement unit 10 does not move in the second direction y in conjunction with it. In addition, the engagement of the first engagement portion 15 and the first protrusion 41 is performed at two locations, thereby having an effect of preventing the loading platform 40 from rotating as viewed from the third direction z.

  The second engaging portion 16 is slidably engaged with the first engaging member 51 of the fixed base 50 in the first direction x. Thereby, it has the effect which prevents the rotation seen from the 3rd direction z of the horizontal direction movement part 10. FIG.

  The horizontal movement frame 19 is a flat frame having a rectangular hole on the inner side and perpendicular to the third direction z, and the first and second friction members 11 and 12 are attached to the inner rectangular hole, and a piezoelectric body. A vibrator 30 is arranged.

  The vertical movement unit 20 includes third and fourth friction members 21 and 22, a third engagement unit 25, a fourth engagement unit 26, and a vertical movement frame 29. The vertical direction moving unit 20 can move in the second direction y, and when moving, the loading table 40 also moves in the second direction y in conjunction with it.

  The third and fourth friction members 21 and 22 have a rectangular parallelepiped shape, and one of the planes perpendicular to the first direction x is in contact with the piezoelectric vibrator 30, and the vertical movement frame 29 is caused by the vibration of the piezoelectric vibrator 30. At the same time, it can move in the second direction y, and the other is attached inside the vertical movement frame 29.

  The third engagement portion 25 has one elongated hole extending in the first direction x, and one protrusion of the second protrusion 42 of the loading table 40 is slidably engaged in the first direction x. . Therefore, when the loading platform 40 moves in the first direction x as the horizontal movement unit 10 moves in the first direction x, the vertical movement unit 20 does not move in the first direction x in conjunction with it.

  The fourth engagement portion 26 is slidably engaged with the second engagement member 52 of the fixed base 50 in the second direction y. Thereby, it has the effect which prevents the rotation seen from the 3rd direction z of the vertical direction moving part 20. FIG.

  The vertical moving frame 29 has a square shape when viewed from the first direction x, and a part of the horizontal moving frame 19 is disposed in a groove portion constituting the square shape. The horizontal moving unit 10 can move in the first direction x without interfering with the vertical moving unit 20, and the vertical moving unit 20 can move in the second direction y without interfering with the horizontal moving unit 10. It is.

  It is desirable that the horizontal movement frame 19 and the vertical movement frame 29 each have a separate structure in order to simplify assembly. Specifically, the horizontal movement frame 19 includes a horizontal movement frame beam portion 19a, a horizontal movement frame support portion 19b, and a horizontal movement frame tension coil spring 19c (see FIG. 11). The vertical movement frame 29 includes a vertical movement frame beam 29a, a vertical movement frame support 29b, and a vertical movement frame tension coil spring 29c.

  The horizontal movement frame beam portion 19a has one end (right side in FIG. 11) pinned to the horizontal movement frame support portion 19b with a pin, and the other end (left side in FIG. 11) moved in the horizontal direction. It is attached to one end portion of the frame tension coil spring 19c. The other end of the horizontal moving frame tension coil spring 19c is attached to the horizontal moving frame support 19b. Due to the tensile tension of the horizontal moving frame tension coil spring 19c, the other end of the horizontal moving frame beam portion 19a is urged to approach the horizontal moving frame support portion 19b. Based on this biasing, the first and second friction members 11 and 12 pressurize (bias) the piezoelectric vibrator 30 in the second direction y.

  The vertical movement frame beam portion 29a has one end (lower side in FIG. 11) pinned to the vertical movement frame support portion 29b with a pin and the other end (upper side in FIG. 11) in the vertical direction. It is attached to one end of the moving frame tension coil spring 29c. The other end of the vertical moving frame tension coil spring 29c is attached to the vertical moving frame support 29b. The other end of the vertical movement frame beam portion 29a is biased toward the vertical movement frame support portion 29b by the tension of the vertical movement frame tension coil spring 29c. Based on this biasing, the third and fourth friction members 21 and 22 pressurize (bias) the piezoelectric vibrator 30 in the first direction x.

  In addition, it is a figure for demonstrating that the horizontal direction moving frame 19 and the vertical direction moving frame 29 of FIG. 11 are separate structures, and the vertical direction moving frame 29 sees a square-shaped shape seeing from the 1st direction x. A different form from FIG. 2 is shown, such as not having.

  FIG. 11 illustrates the horizontal moving frame 19 and the vertical moving frame 29 having a cantilever structure using a pin and a tension coil spring. However, instead of the pin, a tension coil spring is used to pull both ends of the beam portion and the support portion. It may be a form of energizing with (not shown).

  The piezoelectric vibrator 30 includes hollow cylindrical first and second piezoelectric elements (piezoelectric ceramic rings) 31 and 32 and shims 34 formed of thin metal elastic plates. 1 and 2nd piezoelectric elements 31 and 32 are fixed.

  Electrodes are provided on the surfaces of the first and second piezoelectric elements 31 and 32 viewed from the third direction z (see FIG. 5). The electrodes are radially divided into four when viewed from the third direction z, and the first, second, third, fourth electrodes 31a, 31b, 31c, 31d of the first piezoelectric element 31 and the fifth of the second piezoelectric element 32 are divided. Sixth, seventh, and eighth electrodes 32a, 32b, 32c, and 32d are attached. The electrode may be attached to only one of the first piezoelectric element 31 and the second piezoelectric element 32, but the present embodiment attached to both has a stronger driving force. Can be obtained.

  The electrodes are arranged in the order of the first electrode 31a, the second electrode 31b, the third electrode 31c, and the fourth electrode 31d in the circumferential direction on the plane perpendicular to the third direction and counterclockwise when viewed from the third direction z. Be placed. The first electrode 31a is on the side in contact with the fourth friction member 22, the second electrode 31b is on the side in contact with the first friction member 11, and the third electrode 31c is on the side in contact with the third friction member 21. The electrode 31d is disposed on the side in contact with the second friction member 12 (see FIG. 11). In other words, the first electrode 31a and the third electrode 31c are arranged side by side in the first direction x (arranged in a positional relationship facing the center on the xy plane of the piezoelectric vibrator 30 on the xy plane). The second electrode 31b and the fourth electrode 31d are arranged side by side in the second direction y (arranged in a positional relationship facing the center on the xy plane of the piezoelectric vibrator 30 on the xy plane).

The first electrode 31 a and the fifth electrode 32 a are arranged to face each other in the third direction z, and the first AC voltage VE ₁ having the same waveform is applied from the circuit unit 70. The second electrode 31b and the sixth electrode 32b, is disposed so as to face in a third direction z, the second AC voltage VE ₂ of the same waveform is applied from the circuit unit 70. The third electrode 31 c and the seventh electrode 32 c are arranged to face each other in the third direction z, and the third AC voltage VE ₃ having the same waveform is applied from the circuit unit 70. The fourth electrode 31d and the eighth electrode 32d, is disposed so as to face in a third direction z, the fourth AC voltage VE ₄ of the same waveform is applied from the circuit unit 70.

The amount of movement in the first direction x of the horizontal direction moving unit 10 or the like is adjusted by changing the time width for applying the first AC voltage VE ₁ or the third AC voltage VE ₃ (time division control). The amount of movement of the second direction y, such as the vertical direction moving unit 20 is adjusted by varying the time width for applying a second AC voltage VE ₂ or the fourth AC voltage VE ₄ (time division control).

When the first AC voltage VE ₁ is applied to the first electrode 31a and the fifth electrode 32a, the voltage application is not performed in the third electrode 31c and the seventh electrode 32c, distortion detection is performed. Based on the distortion detection result of the third electrode 31c and the seventh electrode 32c, first electrode 31a, and the first AC voltage VE ₁ applied to the fifth electrode 32a is further adjusted. Adjustment is performed by time division control for varying the time width for applying a first AC voltage VE ₁ (see FIGS. 7 and 8).

FIG. 7 shows the applied voltage waveform and the average driving force when the time for applying the first AC voltage VE ₁ is shortened to reduce the time-average driving force, and FIG. 8 shows the first AC voltage VE ₁ . The applied voltage waveform and the average driving force in the case where the application time is lengthened and the time average driving force is increased are shown.

  Since the applied voltage is adjusted by the time-sharing control, the drive amplitude in the radial direction does not vary due to the adjustment. In order to generate an effective driving force, a predetermined radial amplitude is required. If the applied voltage is adjusted by varying the amplitude, the driving amplitude in the radial direction is reduced when the driving force is reduced, such as when the amount of movement is small, and an effective driving force cannot be obtained. There is a fear. In the present embodiment, even when the driving force is reduced, such as when the amount of movement is small, the driving amplitude in the radial direction does not fluctuate and therefore does not fall below the effective driving force.

When the third AC voltage VE ₃ is applied to the third electrode 31c and the seventh electrode 32c, the voltage applied is not performed in the first electrode 31a and the fifth electrode 32a, the distortion detection is performed. Based on the distortion detection result of the first electrode 31a and the fifth electrode 32a, the third AC voltage VE ₃ applied third electrode 31c, and the seventh electrode 32c is further adjusted. Adjustment is performed by time division control for varying the time width for applying a third alternating voltage VE _3.

When the second AC voltage VE ₂ is applied to the second electrode 31b and the sixth electrode 32b, the voltage applied is not performed in the fourth electrode 31d and the eighth electrode 32d, distortion detection is performed. Based on the distortion detection result in the fourth electrode 31d and the eighth electrode 32d, the second AC voltage VE ₂ applied to the second electrode 31b, and the sixth electrode 32b is further adjusted. Adjustment is performed by time division control for varying the time width for applying a second AC voltage VE _2.

When the fourth AC voltage VE ₄ is applied to the fourth electrode 31d and the eighth electrode 32d, the voltage application is not performed in the second electrode 31b and the sixth electrode 32b, distortion detection is performed. Based on the distortion detection result of the second electrode 31b and the sixth electrode 32b, the fourth AC voltage VE ₄ applied the fourth electrode 31d, and the eighth electrode 32d is further adjusted. Adjustment is performed by time division control for varying the time width for applying a fourth AC voltage VE _4.

  The shim 34 includes a hollow cylindrical shim main body 34a in which the first and second piezoelectric elements 31 and 32 are fixed to both surfaces, and first, second, third, and fourth support portions 35a supported by the fixing base 50. 35b, 35c, 35d. The shim body 34a is a cylindrical outer wall, and is biased in the second direction y by the biasing force of the first friction member 11 and the reaction force of the second friction member 12 against the biasing force of the first friction member 11. The third friction member 21 is biased in the first direction x by the biasing force of the third friction member 21 and the reaction force of the fourth friction member 22 against the biasing force of the third friction member 21. The first, second, third, and fourth support portions 35a, 35b, 35c, and 35d are portions protruding from the shim main body portion 34a, and the fixing member 53 is inserted into the holes of the first support portion 35a, 35b, 35c, and 35d. It is attached. Accordingly, the piezoelectric vibrator 30 including the shim 34 is fixed to the fixed base 50 and does not move. On the other hand, the horizontal direction moving unit 10 and the loading table 40 can move in the first direction x by the vibration of the piezoelectric vibrator 30, and the vertical direction moving unit 20 and the loading table 40 can move in the second direction y. .

In a state where no voltage is applied to each electrode, the first and second piezoelectric elements 31 and 32 are stationary without causing deformation. In the piezoelectric vibrator 30, a portion to which a voltage is applied expands or contracts. For example, when the first AC voltage VE ₁ is applied to the first electrode 31a and the fifth electrode 32a, the portions of the first and second piezoelectric elements 31 and 32 to which the first electrode 31a and the fifth electrode 32a are attached expand or deflated, second electrode 31b, the application of a second AC voltage VE ₂ to the sixth electrode 32b, first, second electrode 31b of the second piezoelectric elements 31 and 32, the portion sixth electrode 32b is attached expansion Or it shrinks. Along with the expansion or contraction of the portion to which the electrode is attached, the first and second piezoelectric elements 31 and 32 expand or contract on the plane perpendicular to the third direction z (in the in-plane direction). , 32 is also inflated or shrunk so that the circular shape seen from the third direction z is deformed on the plane perpendicular to the third direction z (in the in-plane direction).

  When an AC voltage is applied to each electrode, the piezoelectric vibrator 30 (first and second piezoelectric elements 31, 32 and shim 34) repeats expansion and contraction. Piezoelectric vibrator so that the phase difference between the vibration in the radial direction (longitudinal vibration) and the vibration in the driving direction (lateral vibration) is within a predetermined range by setting the frequency of the AC voltage to a predetermined frequency When the shape of 30 changes, any one point of the outer wall portion of the shim main body 34a of the shim 34 can perform an elliptical motion. A method of setting the phase difference between the longitudinal vibration and the lateral vibration within a predetermined range will be described later with reference to FIG.

Due to this elliptical motion, the first and second friction members 11 and 12 that contact the outer wall portion of the shim main body 34 a in a state in which the outer wall portion is biased in the second direction y are in contact with the fixed base 50 and the piezoelectric vibrator 30. The horizontal direction moving part 10 and the loading platform 40 are moved in the first direction x along with the movement in the first direction x. Specifically, a first alternating current is applied to the first electrode 31a and the fifth electrode 32a so as to excite radial vibration (longitudinal vibration) and vibration in the first direction x (lateral vibration) in the piezoelectric vibrator 30. By applying the third AC voltage VE ₃ to the voltage VE ₁ or the third electrode 31c and the seventh electrode 32c, the outer wall portion of the shim main body 34a comes into contact with the first and second friction members 11 and 12. As a result, the elliptical motion is performed, whereby the first and second friction members 11 and 12 are moved in the first direction x with respect to the fixed base 50 and the piezoelectric vibrator 30. On the surfaces of the first and second piezoelectric elements 31, 32, the first electrode 31a and the third electrode 31c (the fifth electrode 32a and the seventh electrode 32c) are on opposite sides in the first direction x with respect to the center of the circle. Therefore, when the AC voltage is applied to the first electrode 31a (fifth electrode 32a) and the third electrode 31c (seventh electrode 32c), the direction of the lateral vibration is reversed, and the direction of the elliptical motion described above is applied. Is also in the opposite direction. Therefore, the moving directions of the first and second friction members 11 and 12 are also reversed.

Similarly, the third and fourth friction members 21 and 22 that contact the outer wall portion of the shim body 34 a in a state of being biased in the first direction x are in the second direction with respect to the fixed base 50 and the piezoelectric vibrator 30. The vertical movement unit 20 and the loading platform 40 are moved in the second direction y along with this movement. Specifically, the second alternating current is applied to the second electrode 31b and the sixth electrode 32b so as to excite radial vibration (longitudinal vibration) and vibration in the second direction y (lateral vibration) in the piezoelectric vibrator 30. By applying the fourth AC voltage VE ₄ to the voltage VE ₂ or the fourth electrode 31d and the eighth electrode 32d, the outer wall portion of the shim body 34a comes into contact with the third and fourth friction members 21 and 22. As a result, the elliptical motion is performed, whereby the third and fourth friction members 21 and 22 are moved in the second direction y with respect to the fixed base 50 and the piezoelectric vibrator 30. On the surfaces of the first and second piezoelectric elements 31, 32, the second electrode 31b and the fourth electrode 31d (sixth electrode 32b and eighth electrode 32d) are on opposite sides in the second direction y with respect to the center of the circle. Therefore, when the AC voltage is applied to the second electrode 31b (sixth electrode 32b) and the fourth electrode 31d (eighth electrode 32d), the direction of the lateral vibration is reversed, and the direction of the elliptical motion described above is applied. Is also in the opposite direction. Therefore, the moving directions of the third and fourth friction members 21 and 22 are also reversed.

By adjusting the dimensional ratio between the inner diameter and the outer diameter of the piezoelectric vibrator 30, the resonance frequency f _R of vibration in the radial direction (longitudinal vibration) and the vibration frequency (transverse vibration) resonance frequency f _{XY in the} driving direction are determined. . FIG. 9 shows the relationship between the drive frequency, gain (amplitude), and phase in the horizontal and vertical directions. The solid line in FIG. 9 shows the relationship between the frequency (gain) (amplitude) and phase of vibration (lateral vibration) in the driving direction in the first direction x, and the broken line shows the frequency and gain ( Amplitude) and phase relationship are shown. Gain lateral vibration (amplitude) frequency at which is the highest, it indicates the resonance frequency f _XY of lateral vibration, vertical vibration gain (amplitude) frequency when the highest, the longitudinal vibration resonance frequency f _R Show. Generally the phase changes greatly at a frequency near the resonance frequency, the predetermined value the difference of the resonant frequency f _R of the resonance frequency f _XY and longitudinal vibration of the lateral vibration is not large, the drive frequency f _D and f _XY and f _R If set to between, a relatively large phase difference can be given between the vibration of the transverse vibration and the vibration of the longitudinal vibration. Further, it is possible to take a relatively large respective amplitudes of vibration of the vibration and the longitudinal vibration of the lateral vibration since the difference between f _XY and f _R is not large. In the above description, the resonance frequency _fXY of the transverse vibration is described assuming the same value in both the first direction x and the second direction y. However, the resonance vibration frequency _fXY is different as long as an elliptical motion having a predetermined amplitude and phase difference can be formed. There may be.

In this embodiment, set to a value between the first to the driving frequency _{f D} of the fourth AC voltage _VE 1 _{~VE 4,} the resonance frequency _{f XY} of transverse vibration, the resonance frequency _{f R} of the longitudinal vibration. The driving frequency f _D, in order to increase the amplitude of vibration in the radial direction, and the resonance frequency f _XY of lateral vibration, and a value between the resonance frequency f _R of the longitudinal oscillation, the phase difference between the horizontal vibration and vertical vibration Is preferably set to a value in the vicinity of 90 degrees and the longitudinal vibration gain exceeding the lateral vibration gain. Friction between the contact portion (the shim body 34a is a cylindrical outer wall portion) and the driven body (friction member) when there is little radial vibration, that is, when the pressing component in the biasing direction is small. This is because a large driving force cannot be obtained because the force increases.

  The loading table 40 includes a loading table main body 40 a, a first protrusion 41, a second protrusion 42, and a magnet 46. The loading table 40 can be moved in the first direction x by the movement of the horizontal movement unit 10, and can be moved in the second direction y by the movement of the vertical movement unit 20. By attaching a member to be moved, the member can be moved in a two-dimensional direction. The member to be moved in the two-dimensional direction is, for example, an optical element such as an image sensor or an image blur correction lens used for image blur correction of the imaging device.

  The fixed base 50 includes a fixed base main body 50a, a first engaging member 51 that supports the horizontal moving part 10 so as to be slidable in the first direction x, and a vertical moving part 20 that is slidable in the second direction y. A second engaging member 52 to be supported and a fixing member 53 for fixing the piezoelectric vibrator 30 are provided. The fixed base main body 50a is a magnetic body.

  A ball 45 is disposed between the loading table body 40a and the fixed table body 50a. The balls 45 are rotatable spherical objects that maintain a constant distance in the third direction z between the loading table body 40a and the fixed table body 50a, and four balls 45 are arranged in the first embodiment. Since the ball 45 moves relative to the fixed base 50 as the loading base body 40a moves in the first direction x and the second direction y, the opposing surfaces of the mounting base main body 40a and the fixed base 50 (ball 45 The part in contact with is flat.

  One end of the magnet 46 fixed to the loading table body 40a is in close proximity to the fixed table body 50a and attracts the loading table body 40a to the fixed table body 50a. The center of the attractive force of the magnet 46 exists inside the quadrilateral surrounded by four balls 45 arranged.

  The circuit unit 70 includes a drive signal generation unit 71, a detection signal processing unit 72, a control unit 73, first to fourth drive units 74a to 74d, first to fourth detection units 75a to 75d, and first to fourth switches. 76a to 76d (see FIG. 10).

Drive signal generating unit 71 outputs a sine wave of the driving frequency f _D.

The first driving unit 74a amplifies the sine wave output from the drive signal generation unit 71, a driving circuit for applying a first AC voltage VE ₁ to the first electrode 31a, and the fifth electrode 32a. The second driving unit 74b amplifies the sine wave output from the drive signal generation unit 71, a driving circuit for applying a second AC voltage VE ₂ to the second electrode 31b and the sixth electrode 32 b,. Third drive unit 74c amplifies the sine wave output from the drive signal generation unit 71, a driving circuit for applying a third alternating voltage VE ₃ to the third electrode 31c and the seventh electrode 32c,. Fourth driver 74d amplifies the sine wave output from the drive signal generation unit 71, a driving circuit for applying a fourth AC voltage VE ₄ to the fourth electrode 31d, and the eighth electrode 32d.

  The first detector 75a detects the amount of distortion of the first electrode 31a and the fifth electrode 32a based on the vibration of the piezoelectric vibrator 30 as a voltage value. The second detector 75b detects the amount of distortion of the second electrode 31b and the sixth electrode 32b based on the vibration of the piezoelectric vibrator 30 as a voltage value. The third detection unit 75c detects the amount of distortion of the third electrode 31c and the seventh electrode 32c based on the vibration of the piezoelectric vibrator 30 as a voltage value. The fourth detection unit 75d detects the distortion amounts of the fourth electrode 31d and the eighth electrode 32d based on the vibration of the piezoelectric vibrator 30 as voltage values.

  The detection signal processing unit 72 performs a predetermined calculation process based on the distortion amounts detected by the first to fourth detection units 75a to 75d to calculate the distortion amount.

  The control unit 73 performs switching control of the first to fourth switches 76a to 76d based on the driving direction, and is opposed on the xy plane with the symmetry axis (the center on the xy plane of the piezoelectric vibrator 30) as a center. A voltage is applied to one of the two electrodes, and the other output voltage is detected. The first to fourth switches 76a to 76d are switching circuits.

  Specifically, when moving the horizontal movement frame 19 in the first direction x and in one direction, the control unit 73 connects the third detection unit 75c to the third electrode 31c and the seventh electrode 32c. Then, switching control for connecting the first driving unit 74a to the first electrode 31a and the fifth electrode 32a is performed. When moving the horizontal movement frame 19 in the first direction x and the other direction, the control unit 73 connects the third drive unit 74c to the third electrode 31c and the seventh electrode 32c, and the first detection unit Switching control for connecting 75a to the first electrode 31a and the fifth electrode 32a is performed. When the vertical moving frame 29 is moved in the second direction y and in one direction, the control unit 73 connects the fourth detection unit 75d to the fourth electrode 31d and the eighth electrode 32d, and the second driving unit. Switching control for connecting 74b to the second electrode 31b and the sixth electrode 32b is performed. When the vertical moving frame 29 is moved in the second direction y and the other direction, the control unit 73 connects the fourth driving unit 74d to the fourth electrode 31d and the eighth electrode 32d, and the second detection unit. Switching control for connecting 75b to the second electrode 31b and the sixth electrode 32b is performed.

The control unit 73 compares the voltage value of each electrode obtained by the detection signal processing unit 72 with a preset target voltage value, and adjusts the voltage applied to the predetermined electrode based on the comparison result. Specifically, the control unit 73 compares a voltage value corresponding to the amount of distortion detected by the first detection unit 75a with a preset target voltage value, and applies the voltage value to the third electrode 31c and the seventh electrode 32c. the third application time width of the AC voltage VE ₃ to be adjusted. The control unit 73 compares the voltage value corresponding to the distortion amount detected by the second detection unit 75b with a preset target voltage value, and applies the fourth voltage to the fourth electrode 31d and the eighth electrode 32d. adjusting the application time width of the AC voltage VE _4. The control unit 73 compares the voltage value corresponding to the distortion amount detected by the third detection unit 75c with a preset target voltage value, and applies the first voltage to the first electrode 31a and the fifth electrode 32a. The application time width of the AC voltage VE ₁ is adjusted. The control unit 73 compares the voltage value corresponding to the amount of distortion detected by the fourth detection unit 75d with a preset target voltage value, and applies the second value to the second electrode 31b and the sixth electrode 32b. adjusting the application time width of the AC voltage VE _2.

Voltage value detected by the first detector 75a is vibration of the third electrode 31c and the vibration in the radial direction by the third AC voltage VE ₃ applied to the seventh electrode 32c (longitudinal vibration) and the first direction x (horizontal and vibration), fourth AC applied to the second electrode 31b and the sixth vibration in the radial direction by the second AC voltage VE ₂ applied to the electrodes 32 b (longitudinal vibration), or the fourth electrode 31d and the eighth electrode 32d affected by vibration in the radial direction by the voltage VE ₄ (longitudinal vibration). The voltage value detected by the first detection unit 75a is represented by −K _x × VE ₃ + K _r × VE ₃ + K _r × VE ₂ (or VE ₄ ). K _x and K _r are coefficients obtained through experiments, and the target voltage value to be compared with the voltage value detected by the first detection unit 75a is set by the control unit 73 in consideration of this relational expression. The fourth alternating current applied to the second electrode 31b and the sixth vibration in the second direction y by the second AC voltage VE ₂ applied to the electrodes 32 b (lateral vibration), or the fourth electrode 31d and the eighth electrode 32d effects of vibration (lateral vibration) in the second direction y by the voltage VE ₄ does not receive almost.

The voltage value detected by the third detector 75c, the vibration in the radial direction by the first AC voltage VE ₁ applied to the first electrode 31a and the fifth electrode 32a (longitudinal vibration) vibration in the first direction x (horizontal and vibration), fourth AC applied to the second electrode 31b and the sixth vibration in the radial direction by the second AC voltage VE ₂ applied to the electrodes 32 b (longitudinal vibration), or the fourth electrode 31d and the eighth electrode 32d affected by vibration in the radial direction by the voltage VE ₄ (longitudinal vibration). The voltage value detected by the third detection unit 75c is represented by −K _x × VE ₁ + K _r × VE ₁ + K _r × VE ₂ (or VE ₄ ). K _x and K _r are coefficients obtained by experiments. In consideration of this relational expression, the control unit 73 sets a target voltage value to be compared with the voltage value detected by the third detection unit 75c. The fourth alternating current applied to the second electrode 31b and the sixth vibration in the second direction y by the second AC voltage VE ₂ applied to the electrodes 32 b (lateral vibration), or the fourth electrode 31d and the eighth electrode 32d effects of vibration (lateral vibration) in the second direction y by the voltage VE ₄ does not receive almost.

Voltage value detected by the second detector 75b is provided with a vibration in the radial direction of the fourth AC voltage VE ₄ applied to the fourth electrode 31d and the eighth electrode 32d (longitudinal vibration) vibration in the second direction y (horizontal and vibration), the vibration of the first electrode 31a and the first radial direction by the AC voltage VE ₁ applied to the fifth electrode 32a (longitudinal vibration), or the third AC applied to the third electrode 31c and the seventh electrode 32c affected by vibration in the radial direction by the voltage VE ₃ (longitudinal vibration). The voltage value detected by the second detection unit 75b is represented by −K _y × VE ₄ + K _r × VE ₄ + K _r × VE ₁ (or VE ₃ ). K _y and K _r are coefficients obtained by experiments. In consideration of this relational expression, the control unit 73 sets a target voltage value to be compared with the voltage value detected by the second detection unit 75b. The third AC applied to the first electrode 31a and the fifth vibration by the first AC voltage VE ₁ applied to the electrodes 32a in the first direction x (lateral vibration), or the third electrode 31c and the seventh electrode 32c effects of vibration (lateral vibration) in the first direction x by the voltage VE ₃ does not receive almost.

Voltage value detected by the fourth detector 75d, the vibration in the radial direction by the second AC voltage VE ₂ applied to the second electrode 31b and the sixth electrode 32b (vertical vibration) vibration in the second direction y (horizontal and vibration), the vibration of the first electrode 31a and the first radial direction by the AC voltage VE ₁ applied to the fifth electrode 32a (longitudinal vibration), or the third AC applied to the third electrode 31c and the seventh electrode 32c affected by vibration in the radial direction by the voltage VE ₃ (longitudinal vibration). The voltage value detected by the fourth detection unit 75d is represented by −K _y × VE ₂ + K _r × VE ₂ + K _r × VE ₁ (or VE ₃ ). K _y and K _r are coefficients obtained through experiments. In consideration of this relational expression, the control unit 73 sets a target voltage value to be compared with the voltage value detected by the fourth detection unit 75d. The third AC applied to the first electrode 31a and the fifth vibration by the first AC voltage VE ₁ applied to the electrodes 32a in the first direction x (lateral vibration), or the third electrode 31c and the seventh electrode 32c effects of vibration (lateral vibration) in the first direction x by the voltage VE ₃ does not receive almost.

When the resonance frequency f _R of the longitudinal vibration and the resonance frequency f _{XY of the} lateral vibration change with temperature change or aging change, the drive frequency f _D is adjusted. Specifically, a first electrode 31a and the fifth electrode 32a, the distortion amount of the second electrode 31b and the in the same first AC voltage VE ₁ sixth electrode 32b is applied, the third electrode 31c and the seventh electrode 32c The phase difference between the voltage value based on the voltage value, the voltage value based on the distortion amount of the fourth electrode 31d and the eighth electrode 32d, and the voltage value predicted in advance is compared. The positive and negative and the magnitude of the phase difference, to determine the variation degree of the resonance frequency f _R or lateral oscillation of the resonance frequency f _XY of the longitudinal vibration. Depending on the variation degree of the resonance frequency f _R or lateral oscillation of the resonance frequency f _XY of vibration, by adjusting the driving frequency f _D, it is possible to maintain an effective driving force.

  In the present embodiment, it is possible to simplify the circuit configuration as compared with a mode in which a voltage is simultaneously applied to all four electrodes to perform movement control in a predetermined direction.

Further, since only one type of driving frequency (frequency f _D ) is required to apply an AC voltage to the electrodes, the circuit configuration is not complicated.

  Further, movement control in two directions can be realized with one piezoelectric vibrator. Therefore, the size of the piezoelectric vibrator can be increased as compared with the case where the movement control in two directions is performed using two or more piezoelectric vibrators. If the dimensions can be increased, the drive frequency can be set to about 100 kHz, and the drive circuit (circuit unit 70) can be formed without considering the switching loss that occurs when the drive frequency is set to about 200 to 300 kHz higher than that. It has merit that can be designed.

  The first and second friction members 11 and 12 in the horizontal movement frame 19 apply pressure (bias) in the first direction x of the piezoelectric vibrator 30, and the third and second in the vertical movement frame 29. Since the four friction members 21 and 22 apply pressure (bias) in the second direction y of the piezoelectric vibrator 30, a mechanism for applying pressure from the outside of the horizontal movement frame 19 and the vertical movement frame 29 is provided. Since it is not necessary to prepare, the apparatus can be reduced in size. In addition, there is an advantage that it is easy to balance the entire apparatus. However, the form of the horizontal direction movement part 10 and the vertical direction movement part 20 is not restricted to this.

  In the present embodiment, the first and second piezoelectric elements 31 and 32 and the shim body 34a are hollow in view of downsizing of the apparatus and improvement in driving efficiency of the piezoelectric vibrator. Although it has a cylindrical shape, m can be moved two-dimensionally even if it is a multiple of 4 and other shapes such as a regular m-square or a cylindrical shape.

  The two-dimensional movement device 1 in the present embodiment biases the piezoelectric vibrator 30 in the first direction x and the second direction y, but does not bias it in the third direction z. Therefore, since a member that increases the size in the third direction z is not required, the driven body can be translated in a two-dimensional direction without increasing the thickness in the direction perpendicular to the moving plane.

It is a perspective view of the two-dimensional movement apparatus which notched the loading platform in this embodiment partially. It is a perspective view which shows the structure of a horizontal direction moving part, a vertical direction moving part, and a piezoelectric vibrator. It is a block diagram of the cross section in the AA of FIG. It is a block diagram of the cross section in the BB line of FIG. 1 is a configuration diagram of a piezoelectric vibrator in a first embodiment. FIG. It is a block diagram of the cross section in the CC line | wire of FIG. It is a graph which shows the applied voltage waveform and average drive force at the time of shortening the time which applies a 1st alternating voltage, and making time average drive force small. It is a graph which shows the applied voltage waveform and average drive force at the time of lengthening the time which applies a 1st alternating voltage, and enlarging time average drive force. It is a graph which shows the relationship between the drive frequency of a horizontal direction and a vertical direction, a gain (amplitude), and a phase. It is a block diagram of a circuit part. It is a perspective view which shows the cantilever structure of a horizontal direction moving frame and a vertical direction moving frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Two-dimensional moving apparatus 10 Horizontal direction moving part 11, 12 1st, 2nd friction member 15, 16 1st, 2nd engaging part 19 Horizontal direction moving frame 19a Horizontal direction moving frame beam part 19b Horizontal direction moving frame support part 19c Horizontal moving frame tension coil spring 20 Vertical moving parts 21, 22 Third and fourth friction members 25, 26 Third and fourth engaging parts 29 Vertical moving frame 29a Vertical moving frame beam part 29b Vertical moving Frame support portion 29c Vertical moving frame tension coil spring 30 Piezoelectric vibrators 31, 32 First and second piezoelectric elements 31a, 31b, 31c, 31d First, second, third, fourth electrodes 32a, 32b, 32c 32d 5th, 6th, 7th, 8th electrode 34 shim 34a shim body 35a, 35b, 35c, 35d 1st, 2nd, 3rd, 4th support 40 loading platform 40a loading Main body parts 41, 42 First and second protrusions 45 Ball 46 Magnet 50 Fixed base 50a Fixed base main body parts 51, 52 First and second engaging members 53 Fixed member 70 Circuit part 71 Drive signal generating part 72 Detection signal processing Unit 73 Control unit 73
74a~74d first to fourth driver 75a~75d first to fourth detector 76a~76d first to fourth switch VE _{1, VE 2,} VE 3, VE ₄ first, second, third, 4 AC voltage

Claims (10)

A shim having an outer wall;
A piezoelectric element fixed to the shim in a third direction perpendicular to both the first direction perpendicular to the outer wall and the second direction perpendicular to the outer wall and the first direction;
On the piezoelectric element, first to fourth electrodes arranged in order in a circumferential direction on a plane perpendicular to the third direction are attached,
A first alternating voltage is applied to the first electrode;
A second alternating voltage is applied to the second electrode;
A third AC voltage is applied to the third electrode;
A fourth AC voltage is applied to the fourth electrode;
When the first urging member that urges the outer wall portion in the second direction is moved in one of the first directions, one of the first and third AC voltages is applied,
When the second urging member that urges the outer wall portion in the first direction is moved in one of the second directions, one of the second and fourth AC voltages is applied,
When moving the first urging member in the other direction of the first direction, one of the first and third AC voltages is applied,
When the second urging member is moved in the other direction of the second direction, the voltage of the other one of the second and fourth AC voltages is applied.   The first electrode and the third electrode are arranged side by side in the first direction, and the second electrode and the fourth electrode are arranged side by side in the second direction. The piezoelectric vibrator according to 1. The first AC voltage is adjusted based on a distortion amount of the third electrode,
The second AC voltage is adjusted based on the strain amount of the fourth electrode,
The third AC voltage is adjusted based on a distortion amount of the first electrode,
2. The piezoelectric vibrator according to claim 1, wherein the fourth AC voltage is adjusted based on a distortion amount of the second electrode. By applying the first AC voltage, the longitudinal vibration in the radial direction of the piezoelectric vibrator and the lateral vibration in the first direction of the piezoelectric vibrator are excited,
By applying the second AC voltage, the longitudinal vibration and the lateral vibration in the second direction of the piezoelectric vibrator are excited,
By applying the third AC voltage, the longitudinal vibration and the lateral vibration in the first direction are excited,
2. The piezoelectric vibrator according to claim 1, wherein the longitudinal vibration and the lateral vibration in the second direction are excited by the application of the fourth AC voltage.   5. The drive frequency of the first to fourth AC voltages is set to a value between the resonance frequency of the longitudinal vibration and the resonance frequency of the transverse vibration in the first and second directions. The piezoelectric vibrator according to 1. A shim having an outer wall, and is fixed to the shim in a third direction perpendicular to both the first direction perpendicular to the outer wall and the second direction perpendicular to the outer wall and the first direction; A fixed portion having a piezoelectric vibrator having a piezoelectric element to which first to fourth electrodes arranged in order in a circumferential direction on a plane perpendicular to the direction are attached;
A vertical direction moving part that contacts the outer wall part and biases the outer wall part in the first direction;
A horizontal moving part that contacts the outer wall part and biases the outer wall part in the second direction;
A first AC voltage is applied to the first electrode, a second AC voltage is applied to the second electrode, a third AC voltage is applied to the third electrode, and a fourth AC voltage is applied to the fourth electrode And a circuit part that
The piezoelectric vibrator moves the horizontal movement portion in one of the first directions based on the voltage application of one of the first and third AC voltages, and the second and fourth AC voltages. The vertical movement unit is moved to one of the second directions based on the voltage application of either one of the first and third AC voltages, and the horizontal movement is performed based on the voltage application of the other of the first and third AC voltages. And moving the vertical direction moving part to the other of the second direction based on the voltage application of either the second or fourth AC voltage. Two-dimensional moving device. The vertical movement unit moves in the second direction in conjunction with the movement in the second direction, supports the vertical movement unit in a slidable manner in the first direction, and the first of the horizontal movement unit. A loading platform that moves in the first direction in conjunction with the movement in the direction and slidably supports the horizontal movement portion in the second direction;
A fixing unit that includes the piezoelectric vibrator, supports the vertical movement unit in a slidable manner in the second direction, and supports the horizontal movement unit in a slidable manner in the first direction; The two-dimensional movement apparatus according to claim 6. The circuit unit includes a first detection unit that detects a distortion amount of the first electrode when the third AC voltage is applied to the third electrode, and the fourth AC voltage is applied to the fourth electrode. A second detector for detecting the amount of distortion of the second electrode, and a third detector for detecting the amount of distortion of the third electrode when the first AC voltage is applied to the first electrode; A fourth detector that detects the amount of distortion of the fourth electrode when the second AC voltage is applied to the second electrode; and a controller.
The control unit adjusts the first AC voltage based on a distortion amount detected by the third detection unit, and adjusts the second AC voltage based on a distortion amount detected by the fourth detection unit. The third AC voltage is adjusted based on the amount of distortion detected by the first detector, and the fourth AC voltage is adjusted based on the amount of distortion detected by the second detector. The two-dimensional movement apparatus according to claim 6.   The circuit unit includes a first switch connecting the first electrode and the first detection unit when the third AC voltage is applied to the third electrode, and the fourth AC voltage applied to the fourth electrode. A second switch connecting the second electrode and the second detection unit when applied, and the third electrode and the third detection unit when the first AC voltage is applied to the first electrode. 9. The apparatus according to claim 8, further comprising a third switch to be connected and a fourth switch for connecting the fourth electrode and the fourth detection unit when the second AC voltage is applied to the second electrode. The two-dimensional movement apparatus as described in.   The two-dimensional movement apparatus according to claim 8, wherein the adjustment of the first to fourth AC voltages is performed by time-sharing control for adjusting a time width for applying the first to fourth AC voltages.

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