JP2007158055A - Piezoelectric element, piezoelectric transducer, and electronic equipment using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode structure for improving the utilization efficiency of a piezoelectric element by increasing the ratio of a part that becomes effective for drive, in a piezoelectric element utilizing a longitudinal piezoelectric effect, especially a layered piezoelectric element having a simple manufacturing process. <P>SOLUTION: The piezoelectric element comprises a first group of electrodes comprising a plurality of electrodes arranged in parallel on a first surface, a second group of electrodes comprising a plurality of electrodes arranged between adjacent electrodes for composing the first group of the electrodes, a third group of electrodes comprising a plurality of electrodes arranged in parallel to the second surface, and a fourth group of electrodes comprising a plurality of electrodes arranged between adjacent electrodes for composing the third group of electrodes. Electrodes for composing the first group of the electrodes arranged on the first surface and the second group of the electrodes do not overlap with electrodes, for composing the third group of the electrodes arranged on the second surface and the fourth group of the electrodes in a thickness direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric transducer such as an actuator or a sensor using a piezoelectric element, and an electronic device using the piezoelectric transducer.

  In recent years, as electronic devices have been reduced in size, thickness, functionality, and power consumption, transducers such as sensors, transformers, and actuators mounted on electronic devices have increased in number.

  The piezoelectric element is a sintered body made of PZT (lead zirconate titanate) or barium titanate as a raw material, and the polarization direction when an electric field is applied to the polarization direction according to the required transducer specifications. It is selected whether to use strain (piezoelectric longitudinal effect) or to use strain (piezoelectric lateral effect) in a direction orthogonal to the polarization direction when an electric field is applied in the polarization direction. In addition, in order to drive the piezoelectric element at a low voltage and reduce the impedance, there is an increasing number of cases in the form of a laminated piezoelectric element in which a plurality of piezoelectric elements are laminated.

However, the use method of the piezoelectric element (piezoelectric effect) is limited as described above, and the degree of freedom in designing the piezoelectric transducer is low. In addition, since the laminated piezoelectric element using the piezoelectric longitudinal effect has to be laminated in the longitudinal direction, it is difficult to manufacture the monolithic structure, and there is no choice but to bond the single plate element with an adhesive or use fastening means such as bolts and nuts. . Therefore, an electrode that can use the piezoelectric longitudinal effect while using a manufacturing method (a manufacturing process of a laminated piezoelectric element using a piezoelectric lateral effect) in which a plurality of piezoelectric material sheets provided with electrodes on one surface are laminated and then sintered integrally. A structure and a multilayer piezoelectric element using the same have been devised (Patent Document 1).
Patent application publication number JP-A-2005-6495

  However, as shown in Patent Document 1, the method in which an electric field is applied between electrodes provided in one surface of a piezoelectric element has a drawback that the piezoelectric element in the vicinity of the electrode does not contribute to the operation. This also led to a decrease in sensitivity when this piezoelectric element was used as a sensor.

  An object of the present invention is to improve the use efficiency of a piezoelectric element by increasing the ratio of a portion that is effective for driving in a piezoelectric element that can utilize the piezoelectric longitudinal effect, particularly a laminated piezoelectric element.

  Therefore, in order to solve the above-described problem, the piezoelectric element of the present invention is provided between a first electrode group composed of a plurality of electrodes arranged in parallel to the first surface and an adjacent electrode constituting the first electrode group. A second electrode group composed of a plurality of electrodes arranged on the substrate, a third electrode group composed of a plurality of electrodes arranged in parallel with the second surface of the piezoelectric element, and a neighbor constituting the third electrode group A fourth electrode group comprising a plurality of electrodes disposed between the matching electrodes, the first electrode group disposed on the first surface, the second electrode group, The third electrode group and the fourth electrode group arranged on the second surface are arranged at positions that do not overlap in the thickness direction.

  According to this, in the vicinity of the electrode in one surface, the piezoelectric effect between the electrodes provided in the other surface works, so that the portion effective for driving can be enlarged.

  Since the piezoelectric element of the present invention is a laminated piezoelectric element that can utilize the piezoelectric longitudinal effect, it is small in size and can provide a high output at a low voltage. In particular, since the ratio of the portion effective for actual driving is higher than that of the conventional multilayer piezoelectric element, this effect is further enhanced. The cost of the multilayer piezoelectric element is greatly increased through a manufacturing process in which the multilayer piezoelectric elements of a size that can provide a plurality of target multilayer piezoelectric elements are integrally sintered and divided into individual multilayer piezoelectric elements. Be lowered. A multilayer piezoelectric element with small individual characteristic variations and high reliability can be obtained.

  In addition, if this multilayered piezoelectric element is applied to a transducer such as an actuator or a sensor and further mounted on an electronic device, a small electronic device with low power consumption and high reliability can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a diagram showing an electrode structure of the piezoelectric element 1 of the present invention. The piezoelectric element 1 has a rectangular shape as shown in FIG. FIGS. 1A, 1B, 1C, and 1D show the piezoelectric element 1 viewed from the directions of arrows 100a, 100b, 100c, and 100d, respectively. In the direction parallel to the width (short side) of the upper surface (first surface) of the piezoelectric element 1, rectangular electrodes 2a, 2b, 2c, 2d, 2e, 2f, as shown in FIG. 2g and 2h are provided in parallel. The electrodes 2a, 2b, 2c, 2d, 2e, 2f, 2g, and 2h constitute a first electrode group. Between adjacent electrodes constituting the first electrode group, electrodes 2i, 2j, 2k, 2l, 2m, 2n, 2o and 2p constituting the second electrode group are provided in parallel.

  In the direction parallel to the width (short side) of the lower surface (second surface) of the piezoelectric element 1, rectangular electrodes 3a, 3b, 3c, 3d, 3e, 3f, as shown in FIG. 3g and 3h are provided in parallel. The electrodes 3a, 3b, 3c, 3d, 3e, 3f, 3g, and 3h constitute a third electrode group. Between the adjacent electrodes constituting the third electrode group, electrodes 3i, 3j, 3k, 3l, 3m, 3n, 3o, 3p constituting the fourth electrode group are provided in parallel.

  And the first electrode group disposed on the first surface, the electrodes constituting the second electrode group, the third electrode group disposed on the second surface, the electrodes constituting the fourth electrode group, Are arranged at positions that do not overlap in the direction of the thickness (the shorter side in FIGS. 1A and 1C).

  One ends of the electrodes 2a, 2b, 2c, 2d, 2e, 2f, 2g, and 2h constituting the first electrode group reach the first side surface of the piezoelectric element 1 and are short-circuited by the side surface electrode 4a. The other ends of the electrodes 2a, 2b, 2c, 2d, 2e, 2f, 2g and 2h do not reach the second side surface of the piezoelectric element 1.

  One ends of the electrodes 2i, 2j, 2k, 2l, 2m, 2n, 2o, and 2p constituting the second electrode group reach the second side surface of the piezoelectric element 1 and are short-circuited by the side surface electrode 5a. The other ends of the electrodes 2i, 2j, 2k, 2l, 2m, 2n, 2o, and 2p do not reach the first side surface of the piezoelectric element 1.

  One ends of the electrodes 3a, 3b, 3c, 3d, 3e, 3f, 3g, and 3h constituting the third electrode group reach the second side surface of the piezoelectric element 1, and are short-circuited by the side surface electrode 5b. The other ends of the electrodes 3a, 3b, 3c, 3d, 3e, 3f, 3g, and 3h do not reach the first side surface of the piezoelectric element 1.

  One end of the electrodes 3i, 3j, 3k, 3l, 3m, 3n, 3o, and 3p constituting the fourth electrode group reaches the first side surface of the piezoelectric element 1 and is short-circuited by the side electrode 4b. The other ends of the electrodes 2i, 2j, 2k, 2l, 2m, 2n, 2o, and 2p do not reach the second side surface of the piezoelectric element 1.

  With such an electrode structure, the electrodes 2a, 2b, 2c, 2d, 2e, 2f, 2g, and 2h constituting the first electrode group are energized through the side electrode 4a to the second electrode group. Energization of the electrodes 2i, 2j, 2k, 2l, 2m, 2n, 2o, and 2p constituting the electrodes 3a, 3b, 3c, 3d, 3e, 3f, and the electrodes constituting the third electrode group is performed via the side surface electrode 5a. Energization to 3g and 3h is performed via the side electrode 5b, and energization to the electrodes 3i, 3j, 3k, 3l, 3m, 3n, 3o and 3p constituting the fourth electrode group is performed via the side electrode 4b. I can do it.

  In this structure, the length of each electrode is shorter than the width of the piezoelectric element 1 (one end does not reach the side surface of the piezoelectric element 1), so a part of the piezoelectric element 1 (near both side surfaces) does not contribute to the operation. To do. Therefore, the length of each electrode is made the same as the width of the piezoelectric element 1, and a method using a through-hole electrode is adopted, or only an electrode to be short-circuited is selectively selected by using an insulator and a conductor on the side surface of the piezoelectric element 1. You may use the method of short-circuiting.

  FIG. 2 is a diagram showing the relationship between the electrodes and the polarization direction when the piezoelectric element 1 is viewed from the side. In FIG. 2, an arrow written with the same line as the arrow 200 in the figure indicates the polarization direction. Polarization is performed in the direction of the electrodes constituting the first electrode group, with the electrodes constituting the second electrode group being GND. In addition, the electrode GND constituting the fourth electrode group is polarized in the direction of the electrode constituting the third electrode group. Accordingly, by applying a voltage between the first electrode group and the second electrode group, and between the third electrode group and the fourth electrode group, the piezoelectric element 1 moves in the direction of the arrow 110 (the first electrode group). Group, second electrode group, third electrode group, fourth electrode group).

  For example, when the second electrode group and the fourth electrode group are set to GND and a positive voltage is applied to the first electrode group and the third electrode group, the piezoelectric element 1 contracts, and when a negative voltage is applied, the piezoelectric element 1 Extends. Although it is difficult to be polarized in the thickness direction of the piezoelectric element in which the electrodes 2b, 2c, and 2j constituting the first electrode group and the second electrode group are located, it is not between the third electrode group and the fourth electrode group. The polarization performed in (1) is polarized across the depth in the thickness direction of the piezoelectric element where the electrodes 2b, 2c, 2j are located. Moreover, although it is hard to polarize in the thickness direction of the piezoelectric element in which the electrodes 3a, 3b, 3i constituting the third electrode group and the fourth electrode group are located, the first electrode group and the second electrode group Polarization performed between the electrodes 3a, 3b, and 3i is polarized across the depth in the thickness direction of the piezoelectric element on which the electrodes 3a, 3b, and 3i are located.

  By adopting such an electrode structure, a large portion effective for driving the piezoelectric element 1 can be taken. In particular, this effect is maximized by arranging the electrodes constituting the third electrode group and the fourth electrode group between the adjacent electrodes constituting the first electrode group and the second electrode group.

  The distance between the electrode constituting the first electrode group and the electrode constituting the second electrode adjacent to this electrode, the electrode constituting the third electrode group, and the fourth electrode adjacent to this electrode By making the distance between the electrodes constituting the electrode larger than the thickness of the piezoelectric element, the polarization process is basically performed over almost the entire thickness direction of the piezoelectric element 1.

  FIG. 2 (b) is a diagram showing the relationship between the electrodes and the polarization direction when the laminated piezoelectric element 102 which is stacked and bonded so that the upper and lower sides of the piezoelectric element 101 without electrodes are sandwiched between the piezoelectric elements 1 is viewed from the side. The operating principle in this case is also basically the same as the operating principle of the piezoelectric element 1 (extends and contracts in the direction of the arrow 111), and the details are omitted. However, the first electrode can be obtained by reducing the thickness of each piezoelectric element to be laminated. Since the distance between the electrodes constituting the group and the electrodes constituting the second electrode group and the distance between the electrodes constituting the third electrode group and the fourth electrode group can be reduced, the drive voltage can be reduced. Can be lowered.

  And when manufacturing such a laminated piezoelectric element, electrodes are printed on a piezoelectric sheet having a size capable of taking a plurality of piezoelectric elements, and a plurality of these are stacked and temporarily fired, and then the size of each piezoelectric element is obtained. A large number of laminated piezoelectric elements can be manufactured at a time by performing a polarization process to obtain individual piezoelectric elements after cutting into a main body and firing. Here, the step of cutting to the size of each piezoelectric element may be after the main firing.

Next, a piezoelectric actuator using the piezoelectric elements 1 and 101 of the present invention will be described with reference to FIG. One ends of the piezoelectric elements 1 and 101 are fixed to the support plate 7. A movable body 6 serving as a stage is fixed to the other ends of the piezoelectric elements 1 and 101, and the piezoelectric elements 1 and 101 and the movable body 6 function as a piezoelectric actuator. An operating member 8 is placed on the moving body 6. The operating member 8 is, for example, a sample, and the operating member 8 is finely moved in the direction of an arrow 112 by expanding and contracting the piezoelectric elements 1 and 101 in a work under a microscope that requires fine adjustment.
With such a configuration, a stage capable of precise positioning can be realized.

(Embodiment 2)
An ultrasonic motor will be described as a piezoelectric actuator using the piezoelectric element of the present invention. FIG. 4 is a view showing a configuration of a linear ultrasonic motor using the piezoelectric element 9 of the present invention as a vibrating body. The rectangular piezoelectric element 9 is provided with protrusions 10 a and 10 b and a protrusion-shaped support member 11. The shaft portion 12a of the pressing member 12 is guided by the guide hole 13a of the guide plate 13 so as to be movable only in the axial direction. A movable body 15 guided by guide rollers 16a and 16b is provided under the protrusions 10a and 10b. The support member 11 is engaged with the V groove portion 12 b of the pressure member 12. The pressure member 12 is pressurized by the pressure means 14, and the protrusions 10a and 10b and the moving body 15 are in contact with each other.

  The piezoelectric element 9 excites longitudinal vibration and bending vibration. 5A and 5B are diagrams showing the vibration amplitude in the long side direction of the piezoelectric element 9, FIG. 5A shows the state of longitudinal vibration, and FIG. 5B shows the state of bending vibration. . The central portion of the piezoelectric element 9 serves as a vibration node for both longitudinal vibration and bending vibration, and a support member 11 is provided at this position. Further, the protrusions 10a and 10b are provided at the positions of the antinodes of the bending vibration. By simultaneously exciting the longitudinal vibration and the bending vibration, the protrusions 10a and 10b perform an elliptical motion consisting of a displacement in the long side direction of the piezoelectric element 9 and a displacement in a direction perpendicular thereto, thereby driving the moving body 15. Incidentally, the movable body 15 may be fixed and the vibrating body (piezoelectric element 9) itself may be driven.

  Next, the electrode configuration of the piezoelectric element 9 will be described with reference to FIG. Here, only the difference from the piezoelectric element 1 shown in the first embodiment is shown, and the detailed operation of the piezoelectric element 9 is omitted.

  A first electrode group, a second electrode group, and a third electrode group are provided in four regions divided by a line connecting the central portions of the two sides of the piezoelectric element 9, respectively. That is, the electrodes 18 (18a, 18b, 18c), 21 (21a, 21b, 21c), 24 (24a, 24b, 24c), 27 (27a, 27b, 27c) constitute a first electrode group. From the electrode group consisting of the electrode 19 (19a, 19b, 19c) and the short-circuit electrode 20, the electrode group consisting of the electrode 22 (22a, 22b, 22c) and the short-circuit electrode 23, the electrode 25 (25a, 25b, 25c) and the short-circuit electrode 26 The electrode group consisting of the electrodes 28 (28a, 28b, 28c) and the short-circuit electrode 29 constitutes a second electrode group.

  The electrodes 30 (30a, 30b, 30c), 33 (33a, 33b, 33c), 36 (36a, 36b, 36c), 39 (39a, 39b, 39c) constitute a third electrode group. From the electrode group consisting of the electrode 31 (31a, 31b, 31c) and the short-circuit electrode 32, the electrode group consisting of the electrode 34 (34a, 34b, 34c) and the short-circuit electrode 35, the electrode 37 (37a, 37b, 37c) and the short-circuit electrode 38 The electrode group consisting of the electrode group consisting of the electrode 40 (40a, 40b, 40c) and the short-circuit electrode 41 constitutes a fourth electrode group. The piezoelectric element 9 is obtained by applying an AC voltage between the two pairs of the first electrode group and the second electrode group located on the diagonal and between the two sets of the third electrode group and the fourth electrode group. In this case, longitudinal vibration and bending vibration are excited, and the movable body 15 is driven by the protrusions 10a and 10b having an elliptical motion. When an alternating voltage is applied between the two pairs of the first electrode group and the second electrode group on the other diagonal line and between the two sets of the third electrode group and the fourth electrode group, the piezoelectric element 9 Since the phases of the longitudinal vibration and the bending vibration excited by are reversed, the moving direction of the moving body 15 is reversed.

  That is, an alternating voltage is applied between the electrode 18 and the electrode 19, between the electrode 27 and the electrode 28, between the electrode 36 and the electrode 37, between the electrode 33 and the electrode 34, or between the electrode 24 and the electrode 25, and between the electrode 21 and the electrode 21. The moving body 15 is driven by applying an AC voltage between the electrode 30 and the electrode 22, between the electrode 30 and the electrode 31, and between the electrode 39 and the electrode 40. This embodiment shows an example of an electrode pattern for realizing an ultrasonic motor based on the driving principle of the piezoelectric element of the present invention. Any electrode pattern can be formed according to the driving principle of the piezoelectric element of the present invention. You may comprise.

(Embodiment 3)
A piezoelectric transformer using the piezoelectric element of the present invention will be described. FIG. 10 shows a block diagram of the piezoelectric transformer of the present invention. The laminated piezoelectric element 17 serving as a piezoelectric transformer is functionally divided into a primary side element and a secondary side element. The primary element is provided with a first electrode group 42, a second electrode group 43, a third electrode group 44, and a fourth electrode group 45. When an alternating voltage having a predetermined frequency is applied from the oscillation circuit 59 between the first electrode group 42 and the second electrode group 43 and between the third electrode group 44 and the fourth electrode group 45. The laminated piezoelectric element 17 performs primary longitudinal vibration between the primary side element and the secondary side element, that is, the middle of the laminated piezoelectric element 17 as a node.

  Impedance and output between the electrodes of the primary side element on the input side, that is, between the first electrode group 42 and the second electrode group 43, and between the third electrode group 44 and the fourth electrode group 45. A voltage different from the input voltage is obtained due to the difference in impedance between the electrodes of the secondary side element that is the side, that is, the second electrode group serving as GND, the fourth electrode group, and the fifth electrode group . A high output voltage with respect to the input voltage can be obtained by lowering the impedance of the primary side element and increasing the impedance of the secondary side element.

  Next, the structure of the laminated piezoelectric element 17 will be specifically described. The laminated piezoelectric element 17 has a structure in which piezoelectric elements 17a, 17b, and 17c are laminated as shown in FIG. FIG. 7 is a view showing the electrode structure of the piezoelectric elements 17a, 17b, and 17c, and all are views seen from the upper surface (arrow 100b in FIG. 9). None of the piezoelectric elements has electrodes on the lower surface. The piezoelectric element 17a has no electrode on its upper surface.

  Electrodes 42, 43, 45, and 46 are provided on the primary side elements of the piezoelectric elements 17b and 17c. Since the electrode structure of the primary element is the same as that shown in the first embodiment, a detailed description thereof is omitted. The electrodes 42a, 42b, 42c and 42d constitute a first electrode group, the electrodes 43a, 43b, 43c and 43d constitute a second electrode group, and the electrodes 45a, 45b, 45c and 45d constitute a third electrode group. The electrodes 46a, 46b, 46c, and 46d constitute a fourth electrode group.

  Rectangular electrodes 44a and 44b are provided at the ends of the secondary elements. The piezoelectric elements 17a, 17b, and 17c are stacked as shown in FIG. 9, and short-circuited electrodes are provided to facilitate application of input signals and extraction of output signals.

FIG. 8 is a view of the laminated piezoelectric element 17 as viewed from the side. FIG. 8A is a view as seen from the arrow 100c in FIG. FIG. 8B is a view as seen from the arrow 100b. FIG. 8C is a view as seen from the arrow 100e. FIG. 8D is a diagram viewed from the arrow 100a. FIG. 8E is a view as seen from the arrow 100d. The electrodes 42a, 42b, 42c, and 42d constituting the first electrode group are short-circuited by the short-circuit electrodes 48a, 48b, 48c, and 48d, and then short-circuited by the terminal electrode 56a through the electrodes 52a, 52b, 52c, and 52d. .
The electrodes 43a, 43b, 43c, 43d constituting the second electrode group are short-circuited by the short-circuit electrodes 50a, 50b, 50c, 50d, and then short-circuited by the terminal electrode 56b via the electrodes 53a, 53b, 53c, 53d. . The electrodes 45a, 45b, 45c, 45d constituting the third electrode group are short-circuited by the short-circuit electrodes 49a, 49b, 49c, 49d, and then short-circuited by the terminal electrode 58b via the electrodes 55a, 55b, 55c, 55d. . The electrodes 46a, 46b, 46c, 46d constituting the fourth electrode group are short-circuited by the short-circuit electrodes 51a, 51b, 51c, 51d, and then short-circuited by the terminal electrode 58a through the electrodes 54a, 54b, 54c, 54d. .

  The polarization directions between the first electrode group and the second electrode group in the primary element and between the third electrode group and the fourth electrode group are the same as those shown in the first embodiment. In the secondary side element, the second electrode group and the fourth electrode group are set to GND, and polarization processing is performed between the electrodes 44a and 44b constituting the fifth electrode group.

The piezoelectric transformer composed of the laminated piezoelectric element 17 of the present invention has a high reliability because the primary side element and the secondary side element have the same polarization direction, so that even when the piezoelectric transformer is driven at a high output, the piezoelectric transformer is hardly broken. High output can be obtained.
In the present embodiment, the step-up type piezoelectric transformer has been described as an example. However, the electrode structure of the present invention may be applied to a step-down type piezoelectric transformer.

  As described above, the piezoelectric element of the present invention generates a driving force by applying a voltage. When displacement occurs due to external force, a voltage is generated. Therefore, the electrode of the piezoelectric element of the present invention can be easily applied to the structure of a general piezoelectric sensor such as an acceleration sensor or a gyro sensor. As a result, the degree of freedom in design increases and the manufacture of the laminated piezoelectric element using the piezoelectric longitudinal effect is facilitated, so that a piezoelectric sensor with high sensitivity and high reliability can be realized.

(Embodiment 4)
An electronic device equipped with at least one of the piezoelectric actuator, piezoelectric sensor, and piezoelectric transformer of the present invention will be described.

  FIG. 11 is a block diagram of an electronic device equipped with the piezoelectric actuator of the present invention. The piezoelectric element 63 and the moving body 64 constitute a piezoelectric actuator. When a command from a control circuit 61 such as a CPU in the electronic device is transmitted to the driver 62, the driver 62 outputs a drive signal to the piezoelectric element 63. The moving body 64 moves by receiving the driving force of the piezoelectric element 63. At that time, the operating unit 65 moves by receiving the force of the moving body 64. For example, when the electronic device is a camera, when a command to start zooming is transmitted from the control circuit 61, the driver 62 applies a drive signal to the piezoelectric element 63 to rotate the moving body 64. Here, the form of the piezoelectric actuator is an ultrasonic motor. Under the force of the moving body 64, the lens which is the operating portion 65 is moved through a cam (not shown).

  FIG. 12 is a block diagram of an electronic device equipped with the piezoelectric sensor of the present invention. A signal is output to the signal processing circuit 67 according to the environment to which the piezoelectric sensor 66 is exposed. The signal processed by the signal processing circuit 67 is input to a control circuit 68 such as a CPU in the electronic device, and controls the control unit 69 according to the external environment. For example, when the electronic device is an HDD, when the piezoelectric sensor 66 serving as an acceleration sensor detects the fall of the HDD, the signal processing circuit 67 amplifies the output signal of the piezoelectric sensor 66, converts it into a digital signal, and transmits it to the control circuit 68. The control circuit 68 moves the actuator which is the control unit 69 so as to avoid the head so that the head does not contact the medium.

  FIG. 13 is a block diagram of an electronic device equipped with the piezoelectric transformer of the present invention. The electronic device is a personal computer or the like having a display unit 77. The piezoelectric transformer 71 that has received the signal from the oscillation circuit 70 resonates and outputs an AC voltage that is extremely higher than the input voltage to the signal processing circuit 72. The signal processing circuit 72 performs processing such as rectification, and turns on a backlight 73 for brightening the display unit 77 such as a liquid crystal. Information of the information processing unit including the memory 74 and a control circuit 75 such as a CPU is signal-processed so as to be displayed on the display unit 77 by the driver 76. The backlight 73 is an example of a drive unit driven by the piezoelectric transformer 71, and the piezoelectric transformer 73 of the present invention can be applied to drive any drive unit in an electronic device.

  Transducers such as actuators and sensors using piezoelectric elements, laminated piezoelectric elements of the present invention are small and can be driven at low voltage, have high reliability, have high output or high sensitivity, and can be kept low in cost. Therefore, it can be applied to small electronic devices such as cameras, watches, personal computers, mobile phones, HDDs and optical discs, as well as to information recording devices such as precision stages and robots, industrial and aerospace fields. It can be applied to precision measuring equipment.

It is a figure which shows the electrode structure of the piezoelectric element of this invention. It is a figure which shows the polarization structure of the piezoelectric element of this invention. It is a figure which shows the piezoelectric actuator of this invention. It is a figure which shows the linear ultrasonic motor using the piezoelectric element of this invention. It is another figure which shows the mode of a vibration of the piezoelectric element used for the linear type | mold ultrasonic motor of this invention. It is a figure which shows the electrode structure of the piezoelectric element used for the linear type | mold ultrasonic motor of this invention. It is a figure which shows the electrode structure of the piezoelectric element used for the piezoelectric transformer of this invention. It is a side view of the piezoelectric element used for the piezoelectric transformer of this invention. It is a figure which shows the structure of the piezoelectric element used for the piezoelectric transformer of this invention. It is a block diagram of the piezoelectric transformer of the present invention. It is a block diagram of the electronic device carrying the piezoelectric actuator of this invention. It is a block diagram of the electronic device carrying the piezoelectric sensor of this invention. It is a block diagram of the electronic device carrying the piezoelectric transformer of this invention.

Explanation of symbols

1, 9, 63, 101 Piezoelectric element 2, 3, 18, 19, 21, 22, 25, 27, 28, 30, 33, 34, 36, 37, 38, 39, 40, 42, 43, 44, 45 Electrode 4 Side electrode 20, 23, 26, 29, 32, 35, 38, 41 Short-circuit electrode 17, 102 Laminated piezoelectric element 6, 15, 64 Moving body 8 Working member 10 Projection 11 Support member 13 Guide plate 14 Pressurizing means

Claims (10)

A first electrode group comprising a plurality of electrodes arranged in parallel to the first surface;
A second electrode group comprising a plurality of electrodes disposed between adjacent electrodes constituting the first electrode group;
A third electrode group consisting of a plurality of electrodes arranged parallel to the second surface;
A fourth electrode group composed of a plurality of electrodes arranged between adjacent electrodes constituting the third electrode group, and a piezoelectric element comprising:
The first electrode group disposed on the first surface, the electrodes constituting the second electrode group, the third electrode group disposed on the second surface, and the fourth electrode group A piezoelectric element, characterized in that the piezoelectric element is disposed at a position that does not overlap with the electrode in the thickness direction. The electrodes constituting the third electrode group and the electrodes constituting the fourth electrode group are arranged between the electrodes constituting the first electrode group and the electrodes constituting the second electrode group. 2. The piezoelectric element according to claim 1, wherein By applying a voltage between the first electrode group and the second electrode group, and between the third electrode group and the fourth electrode group, the first electrode group and the second electrode group 2. The piezoelectric element according to claim 1, wherein strain is generated in an arrangement direction of the plurality of electrodes constituting the group, the third electrode group, and the fourth electrode group. The distance between the electrode constituting the first electrode group and the electrode constituting the second electrode adjacent to the electrode, the electrode constituting the third electrode group, and the first adjacent to the electrode 2. The piezoelectric element according to claim 1, wherein an interval between the four electrodes is larger than a thickness of the piezoelectric element. 2. A laminated piezoelectric element comprising a plurality of laminated piezoelectric elements according to claim 1. 2. The piezoelectric element according to claim 1, comprising a plurality of electrode patterns including the first electrode group, the second electrode group, the third electrode group, and the fourth electrode group. A piezoelectric actuator comprising an operating member driven by the piezoelectric element or multilayer piezoelectric element according to claim 1. 7. A piezoelectric sensor characterized in that information is notified by an output signal from the piezoelectric element or laminated piezoelectric element according to any one of claims 1 to 6. 7. A piezoelectric transformer using the piezoelectric element or laminated piezoelectric element according to claim 1. 10. An electronic device comprising at least one of the piezoelectric actuator, the piezoelectric sensor, and the piezoelectric transformer according to any one of claims 7 to 9.

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