JP4729147B2

JP4729147B2 - Drive device and drive element

Info

Publication number: JP4729147B2
Application number: JP2005380495A
Authority: JP
Inventors: 豊土信田
Original assignee: Taiyo Yuden Co Ltd
Current assignee: Taiyo Yuden Co Ltd
Priority date: 2005-12-28
Filing date: 2005-12-28
Publication date: 2011-07-20
Anticipated expiration: 2025-12-28
Also published as: JP2007181384A

Description

本発明は、駆動素子と、該駆動素子を用いて被駆動体ないし被変位体を駆動するための駆動装置（アクチュエータ）に関するものである。 The present invention relates to a driving element and a driving device (actuator) for driving a driven body or a displaced body using the driving element.

従来、カメラの撮影レンズやオーバーヘッドプロジェクタなどの投影レンズ，双眼鏡のレンズ，複写機のレンズなど、光学装置におけるレンズの駆動のほか、プロッタやＸ−Ｙ駆動テーブルのような装置など、駆動部を有する装置一般の駆動技術としては、以下の特許文献１〜８などがある。これらは、圧電素子をゆっくり伸ばし、素早く縮ませる，あるいは、素早く伸ばして、ゆっくり縮ませることにより、慣性力と摩擦力を交互に作用させてリニア駆動させる技術である。特許文献１は、上述したアクチュエータ方式の基本技術であり、他の特許文献２〜特許文献８は、前記方式をどのように使うかを示す文献である。
特開平４−０６９０７０号公報特開平１１−１８４４７号公報特開平１１−４４８９９号公報特開平１１−７５３８２号公報特開２０００−１９３７６公報特開２００３−１４１８２７公報特開２００３−３１７４１０公報特開２００４−５６９５１公報 Conventionally, in addition to driving lenses in optical devices such as projection lenses such as camera photographing lenses and overhead projectors, binocular lenses, and copier lenses, there are drive units such as devices such as plotters and XY drive tables. As a general driving technique of the apparatus, there are the following Patent Documents 1 to 8 and the like. These are techniques for linearly driving an inertial force and a frictional force alternately by slowly extending and quickly contracting a piezoelectric element, or by rapidly extending and slowly contracting. Patent Document 1 is a basic technique of the actuator method described above, and other Patent Documents 2 to 8 are documents showing how to use the method.
JP-A-4-069070 Japanese Patent Laid-Open No. 11-18447 Japanese Patent Laid-Open No. 11-44899 JP-A-11-75382 JP 2000-19376 A JP 2003-141827 A JP 2003-317410 A JP 2004-56951 A

図１０を参照して、上述したアクチュエータ方式の機構を説明する。図１０(A)は駆動装置の概略図，図１０(B)及び(C)は圧電素子の変位量と時間の関係を示す図である。図１０(A)に示すアクチュエータは、圧電素子１００，シャフト１０２，スライダ１０４，レンズ１０６により構成されている。前記圧電素子１００は、一方の面が前記シャフト１０２と連結し、もう一方の面が本体１０８に固定されている。前記スライダ１０４は、前記シャフト１０２が貫通しており、図示しない付勢手段によって、シャフト１０２に対して付勢されている。そして、前記付勢手段によるスライダ１０４とシャフト１０２間の摩擦力を介して、前記スライダ１０４が、シャフト１０２に沿って変位する。スライダ１０４が変位すると、該スライダ１０４の先に取り付けられたレンズ１０６が矢印Ｆ１０ａ又はＦ１０ｂ方向に変位する。なお、シャフト１０２の他方の端部は、バネで抑えられているのみであって固定されていない。 With reference to FIG. 10, the above-described actuator-type mechanism will be described. FIG. 10A is a schematic diagram of the driving device, and FIGS. 10B and 10C are diagrams showing the relationship between the displacement amount of the piezoelectric element and time. The actuator shown in FIG. 10A includes a piezoelectric element 100, a shaft 102, a slider 104, and a lens 106. The piezoelectric element 100 has one surface connected to the shaft 102 and the other surface fixed to the main body 108. The slider 104 penetrates the shaft 102 and is urged against the shaft 102 by urging means (not shown). Then, the slider 104 is displaced along the shaft 102 through the frictional force between the slider 104 and the shaft 102 by the urging means. When the slider 104 is displaced, the lens 106 attached to the tip of the slider 104 is displaced in the direction of the arrow F10a or F10b. Note that the other end of the shaft 102 is only held by a spring and is not fixed.

前記圧電素子１００に、図１０(B)に示すように、圧電素子がゆっくり伸びて素早く縮むように、時間に対して非対称の電気信号を入力して駆動させると、前記圧電素子１００がゆっくり伸びるときに、シャフト１０２が矢印Ｆ１０ａの方向に動く。このとき、前記スライダ１０４は、摩擦力によりスライダ１０４と一緒に動く。次に、圧電素子１００が素早く縮むと、前記スライダ１０４は、慣性力によってその場に留まり、シャフト１０２だけが矢印Ｆ１０ｂ方向に引き寄せられるため、スライダ１０４がシャフト１０２に対して矢印Ｆ１０ａ方向に移動することになる。以上の動作を繰り返すことにより、スライダ１０４は、矢印Ｆ１０ａ方向にリニア駆動する。一方、図１０(C)に示すように、圧電素子１００を、素早く伸びてゆっくり縮むように時間に対して非対称の電気信号を入力して駆動させると、上記と逆の作用により、スライダ１０４が矢印Ｆ１０ｂ方向にリニア駆動する。以上のようなアクチュエータの駆動方式は、構造がシンプルなため、携帯電話用のデジタルカメラモジュールの自動焦点用のアクチュエータなどとして実用化されている。 As shown in FIG. 10B, when the piezoelectric element 100 is driven by inputting an asymmetric electrical signal with respect to time so that the piezoelectric element slowly expands and contracts quickly, as shown in FIG. In addition, the shaft 102 moves in the direction of the arrow F10a. At this time, the slider 104 moves together with the slider 104 by a frictional force. Next, when the piezoelectric element 100 is quickly contracted, the slider 104 stays in place by the inertial force, and only the shaft 102 is pulled in the direction of the arrow F10b, so that the slider 104 moves in the direction of the arrow F10a with respect to the shaft 102. It will be. By repeating the above operation, the slider 104 is linearly driven in the direction of the arrow F10a. On the other hand, as shown in FIG. 10C, when the piezoelectric element 100 is driven by inputting an asymmetric electric signal with respect to time so that it quickly expands and contracts slowly, the slider 104 is moved to an arrow by the reverse action. Linear drive in F10b direction. The actuator driving system as described above has a simple structure and has been put to practical use as an auto-focusing actuator for a digital camera module for mobile phones.

ところで、携帯電話用のデジタルカメラ用のレンズモジュールは、光学素子の高画素化，ズーム，オートフォーカス，手ぶれ防止などの高機能化を低コストで達成することが求められるようになってきている。しかしながら、前記図１０に示す背景技術では、スライダ１０４とシャフト１０２が摩擦力を介して接しているため、固着が生じやすい。特に、圧電素子１００の変位方向と固着力の作用する方向が直交しており、圧電素子１００の変位が固着力の切断（ないし抑制）に直接作用しないため、スライダ１０４を駆動させるためには圧電素子１００を大きく変位させる必要があり、駆動効率が低く、低電圧での駆動が困難であるという不都合がある。 By the way, lens modules for digital cameras for mobile phones have been required to achieve high functionality such as high pixel density, zoom, autofocus, and camera shake prevention at low cost. However, in the background art shown in FIG. 10, since the slider 104 and the shaft 102 are in contact with each other through frictional force, the sticking easily occurs. In particular, the displacement direction of the piezoelectric element 100 and the direction in which the fixing force acts are orthogonal, and the displacement of the piezoelectric element 100 does not directly affect the cutting (or suppression) of the fixing force. There is a disadvantage that the element 100 needs to be greatly displaced, the driving efficiency is low, and driving at a low voltage is difficult.

本発明は、以上の点に着目したもので、その目的は、小型かつ軽量で、より低電圧で安定した変位及び位置決めが可能であるとともに、駆動効率が高い駆動装置及び駆動素子を提供することである。 The present invention focuses on the above points, and an object of the present invention is to provide a driving device and a driving element that are small and light, can be stably displaced and positioned at a lower voltage, and have high driving efficiency. It is.

前記目的を達成するため、本発明の駆動装置は、一部が固定されており、印加電圧により振動する駆動素子，該駆動素子の固定部以外の部分に一端が接続されたシャフト，該シャフトとの摩擦及び慣性力を利用して、前記シャフトの軸方向に移動可能なスライダ，を備えるとともに、前記駆動素子は、前記シャフトの軸方向と該軸方向と交わる方向へ、前記シャフトを振動可能であることを特徴とする。 In order to achieve the above object, a drive device of the present invention is partially fixed, a drive element that vibrates by an applied voltage, a shaft having one end connected to a part other than the fixed part of the drive element, the shaft, The slider is movable in the axial direction of the shaft using the friction and inertial force of the shaft, and the drive element can vibrate the shaft in a direction intersecting with the axial direction of the shaft. It is characterized by being.

主要な形態の一つは、前記スライダを前記シャフトに対して付勢する付勢手段，を設けたことを特徴とする。他の形態は、
(1)前記駆動素子が、圧電体の両主面に外部電極を備えた構造を有するとともに、前記外部電極が設けられた両主面のうちの一方の主面側に前記シャフトが取り付けられ、該シャフトの中心軸が、前記外部電極の中心からずれて配置されていること，
(2)前記駆動素子が、前記接続されたシャフトの軸方向にて圧電体の内部で第１の内部電極と第２の内部電極が交互に積層した構造を有し、かつ、前記圧電体の主面又は端面に第１の外部電極と第２の外部電極を備えるとともに、前記第１の内部電極が前記第１の外部電極に接続され、前記第２の内部電極が前記第２の外部電極に接続され、前記シャフトの中心軸が、前記第１の内部電極と第２の内部電極の重なり部分の中心からずれて配置されていること，
(3)前記駆動素子が中心軸に対して対称振動するとともに、前記シャフトを、前記中心軸からずらして配置したことを特徴とする。 One of the main forms is characterized in that an urging means for urging the slider with respect to the shaft is provided. Other forms are
(1) The drive element has a structure including external electrodes on both main surfaces of the piezoelectric body, and the shaft is attached to one main surface side of both main surfaces provided with the external electrodes , The central axis of the shaft is arranged offset from the center of the external electrode ;
(2) the drive element, inside the first and second internal electrodes of the piezoelectric in the axial direction of the connected shafts have a structure of alternately laminated, and the piezoelectric element Rutotomoni comprising a first external electrode and second external electrodes on the principal surface or the end surface, the first internal electrode connected to the first external electrode, said second internal electrode and the second external Being connected to an electrode, the central axis of the shaft being displaced from the center of the overlapping portion of the first internal electrode and the second internal electrode,
(3) The drive element is oscillated symmetrically with respect to a central axis, and the shaft is arranged to be shifted from the central axis.

更に他の形態は、前記シャフトの軸方向に沿った直進振動と、前記軸方向と交わる方向への屈曲振動を共振させたことを特徴とする。更に他の形態は、前記駆動素子の振動を増幅する増幅手段，を備えたことを特徴とする。 Still another embodiment is characterized in that rectilinear vibration along the axial direction of the shaft and bending vibration in a direction intersecting with the axial direction are resonated. Still another embodiment is characterized in that it comprises an amplifying means for amplifying the vibration of the drive element.

本発明の駆動素子は、軸方向に移動可能なスライダが取り付けられるシャフトの一端を固定するための駆動素子であって、圧電体の両主面に外部電極を備えるとともに、該外部電極が設けられた主面のうちの一方の主面側に前記シャフトが取り付けられ、該シャフトの中心軸が、前記外部電極の中心からずれて配置されていることを特徴とする。 The drive element of the present invention is a drive element for fixing one end of a shaft to which a slider that is movable in the axial direction is attached. The drive element includes external electrodes on both main surfaces of the piezoelectric body, and the external electrodes are provided. The shaft is attached to one main surface side of the main surfaces , and the center axis of the shaft is arranged to be shifted from the center of the external electrode .

他の発明の駆動素子は、軸方向に移動可能なスライダが取り付けられるシャフトの一端を固定するための駆動素子であって、前記固定されるシャフトの軸方向にて圧電体の内部で第１の内部電極と第２の内部電極が交互に積層した構造を有し、かつ、前記圧電体の主面又は端面に第１の外部電極と第２の外部電極を備えるとともに、前記第１の内部電極が前記第１の外部電極に接続され、前記第２の内部電極が前記第２の外部電極に接続され、前記シャフトの中心軸が、前記第１の内部電極と第２の内部電極の重なり部分の中心からずれて配置されていることを特徴とする。

A driving element according to another aspect of the invention is a driving element for fixing one end of a shaft to which a slider that is movable in the axial direction is attached, and the first driving element is formed inside the piezoelectric body in the axial direction of the fixed shaft . internal and second internal electrodes are have a structure of alternately laminated, and Rutotomoni comprises a first external electrode and second external electrodes on the principal surface or the end surface of the piezoelectric, the first An electrode is connected to the first external electrode, the second internal electrode is connected to the second external electrode, and a central axis of the shaft is an overlap of the first internal electrode and the second internal electrode It is characterized by being arranged offset from the center of the part.

一部が固定された請求項８又は９記載の駆動素子，該駆動素子の固定部以外の部分に一端が接続されたシャフト，該シャフトとの摩擦及び慣性力を利用して、前記シャフトの軸方向に移動可能なスライダ，を備えるとともに、前記駆動素子への電圧の印加により、前記シャフトの軸方向と該軸方向と交わる方向へ、前記シャフトを振動させることを特徴とする。本発明の前記及び他の目的，特徴，利点は、以下の詳細な説明及び添付図面から明瞭になろう。 The drive element according to claim 8 or 9, wherein a part of the shaft is fixed, a shaft having one end connected to a portion other than the fixed portion of the drive element, friction and inertial force with the shaft, and an axis of the shaft And a slider that is movable in a direction, and the shaft is vibrated in a direction crossing the axial direction of the shaft and the axial direction by applying a voltage to the driving element. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

本発明は、スライダ（ないし被変位体）の移動を軸方向にガイドするシャフトの一端が固定される駆動素子によって、前記シャフトの軸方向及び該軸方向と交わる方向に、前記シャフトを駆動することとした。このため、固着力を効率よく抑制ないし切断し、小型かつ軽量でありながら、低電圧で安定した効率のよい駆動が可能となる。 The present invention drives the shaft in the axial direction of the shaft and in a direction intersecting with the axial direction by a drive element in which one end of the shaft that guides the movement of the slider (or the displaced body) in the axial direction is fixed. It was. For this reason, the fixing force is efficiently suppressed or cut, and stable and efficient driving at a low voltage is possible while being small and light.

以下、本発明を実施するための最良の形態を、実施例に基づいて詳細に説明する。 Hereinafter, the best mode for carrying out the present invention will be described in detail based on examples.

最初に、図１〜図５を参照しながら、本発明の実施例１を説明する。まず、図１を参照して、本実施例の基本構造を説明する。本実施例は、本発明を光学装置のフォーカス用レンズの駆動装置（アクチュエータ）として使用した例である。図１(A)は、本実施例の全体構成を示す断面図、図１(B)はシャフト及びスライダを軸上から見た平面図である。本実施例の駆動装置（アクチュエータ）１０は、被変位物であるレンズ３４を移動ないし変位させるものであって、前記レンズ３４は、圧電素子１２に一端が接合されたシャフト２０に沿って移動するスライダ２４と、他のシャフト３０に沿って移動するスライダ３２によって保持される構成となっている。前記シャフト２０及び３０は、円柱状や角柱状など、任意の形状としてよい。前記他のシャフト３０は、前記シャフト２０の振動を阻害しない遊びが設けられている。なお、本実施例では、２つのシャフト２０及び３０を用いてレンズ３４を支持することとしたが、シャフト３０については必要に応じて設けるようにすればよい。 First, Embodiment 1 of the present invention will be described with reference to FIGS. First, the basic structure of the present embodiment will be described with reference to FIG. In this embodiment, the present invention is used as a driving device (actuator) for a focusing lens of an optical device. FIG. 1A is a cross-sectional view showing the overall configuration of the present embodiment, and FIG. 1B is a plan view of the shaft and the slider as viewed from above. The driving device (actuator) 10 of this embodiment moves or displaces a lens 34 that is a displacement object. The lens 34 moves along a shaft 20 having one end joined to the piezoelectric element 12. The slider 24 is held by a slider 32 that moves along another shaft 30. The shafts 20 and 30 may have an arbitrary shape such as a columnar shape or a prismatic shape. The other shaft 30 is provided with play that does not hinder the vibration of the shaft 20. In the present embodiment, the lens 34 is supported by using the two shafts 20 and 30, but the shaft 30 may be provided as necessary.

本実施例では、一方のシャフト２０の一端を、圧電素子１２の上面略中央に固定することによって、ステータ２２が形成されている。前記スライダ２４とシャフト２０の間には、付勢手段が設けられている。本実施例では、図１(B)に示すように、前記スライダ２４が２つの略弧状の分割体２４Ａ及び２４Ｂに分割しており、それらの間に、付勢手段２６としてバネが設けられた構成となっている。前記スライダ２４は、前記付勢手段２６によるシャフト２０との摩擦を介して、前記シャフト２０の軸方向（図示のＹ軸方向）に沿って変位可能となっている。他方のシャフト３０に対するスライダ３２の取り付け機構も同様である。 In the present embodiment, the stator 22 is formed by fixing one end of one shaft 20 to the substantially upper center of the piezoelectric element 12. Biasing means is provided between the slider 24 and the shaft 20. In this embodiment, as shown in FIG. 1 (B), the slider 24 is divided into two substantially arc-shaped divided bodies 24A and 24B, and a spring is provided as an urging means 26 therebetween. It has a configuration. The slider 24 can be displaced along the axial direction of the shaft 20 (Y-axis direction in the drawing) through friction with the shaft 20 by the urging means 26. The attachment mechanism of the slider 32 with respect to the other shaft 30 is the same.

前記圧電素子１２は、例えばＰＺＴなどの圧電体１４の両主面に、例えばＡｇ／Ｐｄなどの外部電極１６及び１８を偏らせて配置した構造となっている。すなわち、前記外部電極１６及び１８は、前記シャフト２０に対して、非対称の形状となっている。なお、本実施例では、前記外部電極１６及び１８を、図の左側に偏るように配置することとしたが、右側に偏らせるようにしてもよい。このような構造の圧電素子１２は、一方の外部電極１８側が、図示しない静止部材などに固定されている。また、シャフト３０の一端も、前記静止部材に固定されている。 The piezoelectric element 12 has a structure in which, for example, external electrodes 16 and 18 such as Ag / Pd are biased on both main surfaces of a piezoelectric body 14 such as PZT. That is, the external electrodes 16 and 18 have an asymmetric shape with respect to the shaft 20. In the present embodiment, the external electrodes 16 and 18 are arranged so as to be biased toward the left side of the figure, but may be biased toward the right side. In the piezoelectric element 12 having such a structure, one external electrode 18 side is fixed to a stationary member (not shown) or the like. One end of the shaft 30 is also fixed to the stationary member.

以上のような構成の圧電素子１２は、外部電極１６及び１８に電圧を加えることにより、対向する外部電極１６及び１８間が厚くなる（広がる）方向に伸び、逆方向の電圧を加えることにより、外部電極１６及び１８間が薄くなる方向に縮む。このような電極配置の圧電素子１２では、Ｙ軸方向への変位量は、外部電極１６及び１８の偏りにより、−Ｘ側（左側）の変位Ａの方が、＋Ｘ側（右側）の変位Ｂよりも大きくなる。 The piezoelectric element 12 having the above-described configuration is formed by applying a voltage to the external electrodes 16 and 18, extending in a direction in which the space between the opposing external electrodes 16 and 18 becomes thicker (expanding), and applying a voltage in the opposite direction. The space between the external electrodes 16 and 18 shrinks in the direction of thinning. In the piezoelectric element 12 having such an electrode arrangement, the displacement amount in the Y-axis direction is such that the displacement A on the −X side (left side) is the displacement B on the + X side (right side) due to the bias of the external electrodes 16 and 18. Bigger than.

図２には、前記ステータ２２の振動の周波数特性が示されている。図２(A)は、圧電素子１２の厚みＴｐが１ｍｍ，幅Ｗｐが３ｍｍであって、シャフト２０の高さＴｓが５ｍｍ，幅Ｗｓが１ｍｍの場合である。図２(B)は、圧電素子１２の厚みＴｐが２ｍｍ，幅Ｗｐが３ｍｍであって、シャフト２０の高さＴｓが５ｍｍ，幅Ｗｓが１ｍｍの場合である。図２(A)及び(B)において、横軸は周波数［ｋＨｚ］，縦軸はシャフト２０の先端の変位量［μｍ］を示している。 FIG. 2 shows the frequency characteristics of the vibration of the stator 22. FIG. 2A shows a case where the piezoelectric element 12 has a thickness Tp of 1 mm and a width Wp of 3 mm, and the shaft 20 has a height Ts of 5 mm and a width Ws of 1 mm. FIG. 2B shows a case where the piezoelectric element 12 has a thickness Tp of 2 mm and a width Wp of 3 mm, and the shaft 20 has a height Ts of 5 mm and a width Ws of 1 mm. 2A and 2B, the horizontal axis indicates the frequency [kHz], and the vertical axis indicates the displacement amount [μm] of the tip of the shaft 20.

前記圧電素子１２に、交番電場で周波数を変えて励振すると、圧電素子１２が、図１に示すＹ軸方向の縦振動と、Ｘ−Ｙ面での屈曲振動を生じる。シャフト２０の先端のＸ方向の変位（ＵＸ）と、Ｙ方向の変位（ＵＹ）は、図２(A)及び(B)のグラフに示す通り、それぞれピークを示す。これらのピークは、図３のステータの振動モードのシミュレーション結果にも示すように、屈曲振動１次（Ｂ１），屈曲振動２次（Ｂ２），・・・，縦振動１次（Ｌ１），・・・を示す。圧電素子１２の厚みＴｐが１ｍｍの場合は、図２(A)及び図３(A-1)〜(A-3)に示すように、屈曲の１次ピーク（Ｂ１）が５９ｋＨｚ，屈曲の２次ピーク（Ｂ２）が３０７ｋＨｚ，縦振動の１次ピーク（Ｌ１）が３５０ｋＨｚに生じる。また、圧電素子１２の厚みＴｐを２ｍｍに増すと、図２(B)及び図３(B-1)〜(B-3)に示すように、共振周波数が下がり、屈曲の１次ピーク（Ｂ１）が５３ｋＨｚ，屈曲の２次ピーク（Ｂ）が２７０ｋＨｚ，縦振動の１次ピーク（Ｌ１）が２７８ｋＨｚに移動する。この結果から、圧電素子１２及びシャフト２０の寸法により、共振周波数が変化することが確認できる。 When the piezoelectric element 12 is excited by changing the frequency with an alternating electric field, the piezoelectric element 12 generates longitudinal vibration in the Y-axis direction and bending vibration in the XY plane shown in FIG. The displacement (UX) in the X direction and the displacement (UY) in the Y direction at the tip of the shaft 20 each show a peak as shown in the graphs of FIGS. 2 (A) and 2 (B). As shown in the simulation result of the vibration mode of the stator in FIG. 3, these peaks are bending vibration primary (B1), bending vibration secondary (B2),..., Longitudinal vibration primary (L1),.・・When the thickness Tp of the piezoelectric element 12 is 1 mm, as shown in FIGS. 2 (A) and 3 (A-1) to (A-3), the primary peak of bending (B1) is 59 kHz, and the bending 2 is 2 kHz. The next peak (B2) occurs at 307 kHz, and the primary peak (L1) of longitudinal vibration occurs at 350 kHz. Further, when the thickness Tp of the piezoelectric element 12 is increased to 2 mm, as shown in FIGS. 2 (B) and 3 (B-1) to (B-3), the resonance frequency decreases and the primary peak of bending (B1) ) Moves to 53 kHz, the bending secondary peak (B) moves to 270 kHz, and the longitudinal vibration primary peak (L1) moves to 278 kHz. From this result, it can be confirmed that the resonance frequency changes depending on the dimensions of the piezoelectric element 12 and the shaft 20.

次に、図４も参照して、圧電素子１２の寸法がステータ２２の共振周波数に与える影響についてより詳細に検討する。図４(A)は、シャフト２０の共振周波数と圧電素子１２の厚み（ないし高さ）Ｔｐの関係を示すグラフであって、横軸は圧電素子１２の厚みＴｐ[ｍｍ]，縦軸は共振周波数［ｋＨｚ］を示す。また、圧電素子１２の幅Ｗｐは３ｍｍ，シャフト２０の高さＴｓは５ｍｍで固定した。図４(B)は、シャフト２０の共振周波数と圧電素子１２の幅Ｗｐの関係を示すグラフであって、横軸は圧電素子１２の幅Ｗｐ［ｍｍ］，縦軸は共振周波数［ｋＨｚ］を示す。また、圧電素子１２の厚みＴｐは２ｍｍ，シャフト２０の高さＴｓは５ｍｍで固定した。 Next, the influence of the dimensions of the piezoelectric element 12 on the resonance frequency of the stator 22 will be examined in more detail with reference to FIG. FIG. 4A is a graph showing the relationship between the resonance frequency of the shaft 20 and the thickness (or height) Tp of the piezoelectric element 12. The horizontal axis represents the thickness Tp [mm] of the piezoelectric element 12, and the vertical axis represents the resonance. The frequency [kHz] is indicated. The width Wp of the piezoelectric element 12 was fixed at 3 mm, and the height Ts of the shaft 20 was fixed at 5 mm. FIG. 4B is a graph showing the relationship between the resonance frequency of the shaft 20 and the width Wp of the piezoelectric element 12. The horizontal axis represents the width Wp [mm] of the piezoelectric element 12, and the vertical axis represents the resonance frequency [kHz]. Show. Moreover, the thickness Tp of the piezoelectric element 12 was fixed to 2 mm, and the height Ts of the shaft 20 was fixed to 5 mm.

まず、図４(A)のグラフが示すように、圧電素子１２の厚みＴｐを変化させることによって、屈曲２次と縦振動１次が近づくこと確認される。図示の例では、圧電素子１２の厚みＴｐが２ｍｍのときに、共振周波数が２８０ｋＨｚ付近で近づくことがわかる。また、図４(B)のグラフが示すように、圧電素子１２の幅Ｗｐを変化させることによっても、屈曲２次と縦振動１次が近づくことが確認される。図示の例では、圧電素子１２の幅Ｗｐが３ｍｍのときに、共振周波数が２８０ｋＨｚ付近で近づくことが分かる。このように、圧電素子１２やシャフト２０の寸法を適宜調整することにより、屈曲振動と縦振動（軸方向の振動）の共振周波数が近くなる。そして、屈曲振動と縦振動を効果的に重ね合わせることによって、スライダ２４がシャフト２０に固着しにくくなり、変位量が大きく効率的な駆動をするアクチュエータが得られると考えられる。 First, as shown in the graph of FIG. 4A, it is confirmed that the bending secondary and the longitudinal vibration primary approach each other by changing the thickness Tp of the piezoelectric element 12. In the illustrated example, it can be seen that when the thickness Tp of the piezoelectric element 12 is 2 mm, the resonance frequency approaches in the vicinity of 280 kHz. Further, as shown in the graph of FIG. 4B, it is confirmed that the bending secondary and the longitudinal vibration primary approach each other by changing the width Wp of the piezoelectric element 12. In the illustrated example, it can be seen that when the width Wp of the piezoelectric element 12 is 3 mm, the resonance frequency approaches in the vicinity of 280 kHz. As described above, by appropriately adjusting the dimensions of the piezoelectric element 12 and the shaft 20, the resonance frequencies of the bending vibration and the longitudinal vibration (vibration in the axial direction) become close to each other. By effectively superimposing the bending vibration and the longitudinal vibration, it is considered that the slider 24 is less likely to adhere to the shaft 20, and an actuator that can be driven efficiently with a large displacement is obtained.

次に、図５も参照して、前記圧電素子１２の駆動機構について説明する。図５は、圧電素子１２の変位量と時間の関係を示す図であり、(A)は素早く伸びてゆっくり縮む場合であり、(B)はゆっくり伸びて素早く縮む場合を示す図である。同図において、横軸は時間，縦軸は圧電素子１２のＹ軸方向への変位量を示している。前記圧電素子１２を駆動するには、図５(A)又は(B)に示すように、素早く伸びてゆっくり縮む，あるいは、ゆっくり伸びて素早く縮むというように、時間に対して非対称な電圧信号を外部電極１６及び１８から入力して励振する。 Next, the driving mechanism of the piezoelectric element 12 will be described with reference to FIG. 5A and 5B are diagrams showing the relationship between the displacement amount of the piezoelectric element 12 and time. FIG. 5A is a diagram showing a case where the piezoelectric element 12 is quickly expanded and contracted slowly, and FIG. 5B is a diagram showing a case where the piezoelectric element 12 is slowly expanded and contracted quickly. In the figure, the horizontal axis indicates time, and the vertical axis indicates the amount of displacement of the piezoelectric element 12 in the Y-axis direction. In order to drive the piezoelectric element 12, as shown in FIG. 5 (A) or (B), a voltage signal that is asymmetric with respect to time, such as rapidly expanding and contracting slowly, or slowly extending and contracting quickly, is applied. Input from the external electrodes 16 and 18 for excitation.

まず、図５(A)に示すように、素早く伸びて（ＬＡ）ゆっくり縮む（ＬＢ）ように励振すると、−Ｘ側（図の左側）の変位Ａが、＋Ｘ側（図の右側）の変位Ｂよりも大きいため、シャフト２０は、屈曲しながら図１のＤ１方向へ速く変位し、Ｄ２方向へはゆっくりと変位する。この励振において、スライダ２４には、シャフト２０の屈曲により、シャフト２０の軸に直交した付勢手段２６によるシャフト２０との摩擦力と固着力に抗する方向に力が作用する。すなわち、圧電素子１２が素早く伸び、ゆっくり縮む場合は、素早く伸びるときに、シャフト２０の屈曲により付勢手段２６によるシャフト２０とスライダ２４の固着を切り離し、摩擦を低減するように力が作用し、慣性力と摩擦力との差を大きくして、シャフト２０だけがＤ１方向により動きやすくなるように作用する。また、ゆっくり縮むときは、慣性力よりもスライダ２４の付勢手段２６による摩擦力が大きくなり、スライダ２４はシャフト２０と一体になって、Ｄ２方向に移動する。この繰り返しにより、スライダ２４は、圧電素子１２の変位量が少なくとも、安定して速く−Ｙ方向に変位する。すなわち、低電圧で効率よく−Ｙ方向に変位させることが可能となる。 First, as shown in FIG. 5 (A), when excited so as to quickly expand (LA) and slowly contract (LB), the displacement A on the −X side (left side in the figure) becomes the displacement on the + X side (right side in the figure). Since it is larger than B, the shaft 20 is quickly displaced in the direction D1 in FIG. 1 while being bent, and is slowly displaced in the direction D2. In this excitation, due to the bending of the shaft 20, a force acts on the slider 24 in a direction against the frictional force and the fixing force with the shaft 20 by the urging means 26 orthogonal to the axis of the shaft 20. That is, when the piezoelectric element 12 stretches quickly and shrinks slowly, when the shaft 20 quickly stretches, the bending of the shaft 20 separates the fixation of the shaft 20 and the slider 24 by the biasing means 26, and a force acts to reduce friction, The difference between the inertial force and the frictional force is increased, and only the shaft 20 acts so as to move more easily in the direction D1. In addition, when contracting slowly, the frictional force by the urging means 26 of the slider 24 becomes larger than the inertial force, and the slider 24 moves integrally with the shaft 20 in the direction D2. By repeating this, the slider 24 is displaced in the −Y direction stably and quickly at least by the displacement amount of the piezoelectric element 12. That is, it is possible to efficiently displace in the −Y direction with a low voltage.

逆に、図５(B)に示すように、圧電素子１２がゆっくり伸びて（ＬＣ）素早く縮む（ＬＤ）ように励振すると、素早く縮むときに、屈曲による力がシャフト２０とスライダ２４との固着を切るとともに、慣性力と摩擦力との差が大きくなり、シャフト２０だけがＤ２方向に動きやすくなるように作用する。また、圧電素子１２がゆっくり伸びるときは、スライダ２４がシャフト２０と一体にＤ２方向に移動する。この繰り返しにより、スライダ２４は、圧電素子１２の変位量が少なくとも、安定して速く＋Ｙ方向に変位する。すなわち、低電圧で効率よく＋Ｙ方向に変位させることが可能となる。 On the other hand, as shown in FIG. 5B, when the piezoelectric element 12 is excited so as to slowly expand (LC) and rapidly contract (LD), when the piezoelectric element 12 rapidly contracts, the force due to bending causes the shaft 20 and the slider 24 to adhere to each other. In addition, the difference between the inertial force and the frictional force increases, and only the shaft 20 acts so as to easily move in the D2 direction. Further, when the piezoelectric element 12 extends slowly, the slider 24 moves in the D2 direction integrally with the shaft 20. By repeating this, the slider 24 is displaced in the + Y direction stably and quickly at least by the amount of displacement of the piezoelectric element 12. That is, it is possible to efficiently displace in the + Y direction with a low voltage.

このように、実施例１によれば、シャフト２０の一端が固定される圧電素子１２の外部電極１６及び１８を、前記シャフト２０に対して非対称に配置することによって、シャフト２０の縦振動に加えて屈曲振動も引き出す。そして、前記シャフト２０とスライダ２４間の摩擦力及び固着力に抗する力を作用させて、慣性力とスライダ２４をシャフト２０の同位置に留めようとする力の差を大きくすることとしたので、低電圧で圧電素子の変位量が少なくとも、安定して速く駆動する効率のよい駆動装置１０を得ることができる。 As described above, according to the first embodiment, the external electrodes 16 and 18 of the piezoelectric element 12 to which one end of the shaft 20 is fixed are arranged asymmetrically with respect to the shaft 20. Pull out bending vibration. Since the force against the frictional force and the adhering force between the shaft 20 and the slider 24 is applied, the difference between the inertial force and the force to keep the slider 24 at the same position on the shaft 20 is increased. Thus, it is possible to obtain an efficient driving device 10 that can drive stably and quickly with a low voltage and at least a displacement amount of the piezoelectric element.

次に、図６及び図７を参照しながら、本発明の実施例２を説明する。なお、上述した実施例１と同一ないし対応する構成要素には、同一の符号を用いることとする（以下の実施例についても同様）。図６は、本実施例の駆動装置の全体構成を示す断面図である。上述した実施例１は、圧電素子の外部電極をシャフト２０に対して非対称に配置した例であるが、本実施例は、積層型の圧電素子の内部電極を非対称に配置した例である。図６に示すように、本実施例の駆動装置５０は、積層型の圧電素子５２の上面の略中央部に、シャフト２０の一端を接着してステータ６４が形成されており、前記シャフト２０には、実施例１と同様のスライダ２４が取り付けられている。 Next, Embodiment 2 of the present invention will be described with reference to FIGS. In addition, the same code | symbol shall be used for the component which is the same as that of Example 1 mentioned above, or respond | corresponds (it is the same also about a following example). FIG. 6 is a cross-sectional view showing the overall configuration of the drive device of this embodiment. The first embodiment described above is an example in which the external electrodes of the piezoelectric element are arranged asymmetrically with respect to the shaft 20, but this embodiment is an example in which the internal electrodes of the laminated piezoelectric element are arranged asymmetrically. As shown in FIG. 6, in the driving device 50 of this embodiment, a stator 64 is formed by bonding one end of the shaft 20 to a substantially central portion of the upper surface of the laminated piezoelectric element 52. The same slider 24 as that of the first embodiment is attached.

前記圧電素子５２は、圧電体５４の内部で、第１の内部電極５６Ａ〜５６Ｅと、第２の内部電極５８Ａ〜５８Ｄが交互に重ね合わせられた積層構造となっている。前記第１の内部電極５６Ａ〜５６Ｅは、圧電素子５２の端面に設けられた電極取り出し用の外部電極６０に接続され、第２の内部電極５８Ａ〜５８Ｄは、圧電素子５２の他の端面に設けられた外部電極６２に接続されている。本実施例では、図６に示すように、第１の内部電極５６Ａ〜５６Ｅが、第２の内部電極５８Ａ〜５８Ｄよりも短く設定されており、第１の内部電極５６Ａ〜５６Ｅと第２の内部電極５８Ａ〜５８Ｄの交差している部分が、前記外部電極６０側に偏よっている。すなわち、圧電素子５２の略中央に接合されたシャフト２０に対して、第１の内部電極５６Ａ〜５６Ｅと第２の内部電極５８Ａ〜５８Ｄの重なり具合が、非対称となっている。 The piezoelectric element 52 has a laminated structure in which the first internal electrodes 56A to 56E and the second internal electrodes 58A to 58D are alternately stacked inside the piezoelectric body 54. The first internal electrodes 56 </ b> A to 56 </ b> E are connected to an electrode extraction external electrode 60 provided on the end face of the piezoelectric element 52, and the second internal electrodes 58 </ b> A to 58 </ b> D are provided on the other end face of the piezoelectric element 52. Connected to the external electrode 62. In the present embodiment, as shown in FIG. 6, the first inner electrodes 56A to 56E are set shorter than the second inner electrodes 58A to 58D, and the first inner electrodes 56A to 56E and the second inner electrodes The intersecting portions of the internal electrodes 58A to 58D are biased toward the external electrode 60 side. That is, the overlapping state of the first internal electrodes 56A to 56E and the second internal electrodes 58A to 58D is asymmetric with respect to the shaft 20 joined to the approximate center of the piezoelectric element 52.

このような圧電素子５２の製造方法の一例を示すと、前記圧電体５４として、例えば、機械的品質係数Ｑ値が低い高変位系のＰＺＴ材料を用い、内部電極５６Ａ〜５６Ｅ及び５８Ａ〜５８Ｄとしては、例えばＡｇ／Ｐｄを用いて、積層セラミックコンデンサ（ＭＬＣＣ）と同様に圧電体を電極を交互に形成する。そして、焼成して積層圧電体を得たのち、外部電極６０及び６２を形成して圧電素子５２を製作する。なお、外部電極６０及び６２としては、前記内部電極と同様にＡｇ／Ｐｄを用いるようにしてもよいし、Ａｇ単体で形成するようにしてもよい。 An example of a method for manufacturing such a piezoelectric element 52 is as follows. For example, a high displacement PZT material having a low mechanical quality factor Q value is used as the piezoelectric body 54, and the internal electrodes 56A to 56E and 58A to 58D are used. Uses, for example, Ag / Pd, and alternately forms electrodes of piezoelectric bodies in the same manner as a multilayer ceramic capacitor (MLCC). Then, after firing to obtain a laminated piezoelectric body, external electrodes 60 and 62 are formed to manufacture the piezoelectric element 52. As the external electrodes 60 and 62, Ag / Pd may be used as in the case of the internal electrodes, or may be formed of Ag alone.

前記圧電素子５２は、外部電極６０及び６２に電圧を加えることにより、厚み方向に伸び、逆方向の電圧の印加によって、厚み方向に縮むように分極処理されている。伸縮の変位量は、第１の内部電極５６Ａ〜５６Ｅと第２の内部電極５８Ａ〜５８Ｄの交差部分の偏りにより、外部電極６０側（図の左側）の変位Ａの方が、外部電極６２側（図の右側）の変位Ｂよりも大きい構成となっている。このような構成の圧電素子５２に、前記図５(A)に示す通り、圧電素子が素早く伸びてゆっくり縮むように、立ち上がりが急峻でゆっくりと電圧が下がる鋸波，あるいは、図５(B)に示す通り、圧電素子がゆっくり伸びて素早く縮むように、立ち上がりがゆっくりで急峻に電圧が下がる形態の鋸波を、縦振動の共振周波数で入力した。その結果、圧電素子５２が素早く伸びてゆっくり縮む場合は、前記実施例１と同様に、スライダ２４が−Ｙ方向に変位し、逆に、圧電素子５２がゆっくり伸びて素早く縮む場合は、＋Ｙ方向にスライダ２４が変位する。 The piezoelectric element 52 is polarized so as to extend in the thickness direction by applying a voltage to the external electrodes 60 and 62 and to contract in the thickness direction by applying a voltage in the opposite direction. The displacement amount of expansion / contraction is such that the displacement A on the external electrode 60 side (the left side in the figure) is closer to the external electrode 62 side due to the deviation of the intersection of the first internal electrodes 56A to 56E and the second internal electrodes 58A to 58D. The displacement is larger than the displacement B (right side of the figure). As shown in FIG. 5 (A), the piezoelectric element 52 having such a structure has a sawtooth wave with a steep rise and a slow voltage drop so that the piezoelectric element quickly expands and contracts slowly, or FIG. 5 (B). As shown, a saw wave having a slow rise and a sharp voltage drop was input at the resonance frequency of the longitudinal vibration so that the piezoelectric element stretched slowly and contracted quickly. As a result, when the piezoelectric element 52 rapidly expands and contracts slowly, the slider 24 is displaced in the -Y direction, as in the first embodiment. Conversely, when the piezoelectric element 52 extends slowly and contracts quickly, the + Y direction Thus, the slider 24 is displaced.

図７には、本実施例と比較例について、圧電素子５２の駆動電圧とスライダ２４の変位速度の関係を示す測定結果が示されている。図７において、横軸は駆動電圧Ｖｐｐ［Ｖ］，縦軸は圧電素子５２の変位速度［ｍｍ／ｓ］を表している。なお、比較例は、本実施例２の圧電素子５２の内部電極５６Ａ〜５６Ｅ及び５８Ａ〜５８Ｄを、シャフト２０に対して対称とし、シャフト２０が屈曲振動しない構造としたものである。図７に示す通り、本実施例２では、比較例に比べて、低電圧で駆動し始め、更に、変位速度が速いことが確認された。なお、圧電素子５２やシャフト２０の寸法を調整して、屈曲振動と縦振動を重ねたほうがより望ましいことは、前記実施例と同様である。 FIG. 7 shows the measurement results showing the relationship between the driving voltage of the piezoelectric element 52 and the displacement speed of the slider 24 for this example and the comparative example. In FIG. 7, the horizontal axis represents the drive voltage Vpp [V], and the vertical axis represents the displacement speed [mm / s] of the piezoelectric element 52. In the comparative example, the internal electrodes 56A to 56E and 58A to 58D of the piezoelectric element 52 of the second embodiment are symmetric with respect to the shaft 20, and the shaft 20 does not bend and vibrate. As shown in FIG. 7, in Example 2, it was confirmed that the driving was started at a lower voltage and the displacement speed was higher than that of the comparative example. As in the above-described embodiment, it is more desirable to adjust the dimensions of the piezoelectric element 52 and the shaft 20 to overlap bending vibration and longitudinal vibration.

本実施例２のように、圧電体５４の内部に交互に積層される第１の内部電極５６Ａ〜５６Ｅと、第２の内部電極５８Ａ〜５８Ｄが重なる位置を、前記シャフト２０に対して非対称となるように偏らせて配置する構成としても、前記実施例１と同様の作用・効果が得られる。 As in the second embodiment, the positions where the first inner electrodes 56A to 56E and the second inner electrodes 58A to 58D, which are alternately stacked inside the piezoelectric body 54, are asymmetric with respect to the shaft 20. Even if the configuration is arranged so as to be biased, the same actions and effects as those of the first embodiment can be obtained.

次に、図８を参照しながら、本発明の実施例３を説明する。図８は、本実施例３の全体構成を示す断面図である。上述した実施例１及び２は、圧電素子の外部電極または内部電極を、シャフトに対して非対称となるように偏らせて配置した例であるが、本実施例３は、電極配置に偏りがなく、シャフト自体の位置を調整した構造となっている。図８に示すように、本実施例の駆動装置７０では、シャフト２０の一端が接合される圧電素子７２は、公知の積層セラミックコンデンサと同様に、圧電体７４の内部で、第１の内部電極７６Ａ〜７６Ｅと、第２の内部電極７８Ａ〜７８Ｄが交互に重なった積層型となっている。前記第１の内部電極７６Ａ〜７６Ｅは、外部電極８０に接続され、第２の内部電極７８Ａ〜７８Ｄは、他の外部電極８２に接続されている。 Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view illustrating the overall configuration of the third embodiment. The first and second embodiments described above are examples in which the external electrode or the internal electrode of the piezoelectric element is arranged so as to be asymmetric with respect to the shaft. However, in this third embodiment, there is no bias in the electrode arrangement. The structure is such that the position of the shaft itself is adjusted. As shown in FIG. 8, in the driving device 70 of this embodiment, the piezoelectric element 72 to which one end of the shaft 20 is joined is the first internal electrode inside the piezoelectric body 74, similarly to a known multilayer ceramic capacitor. A stacked type in which 76A to 76E and second internal electrodes 78A to 78D are alternately overlapped is formed. The first internal electrodes 76A to 76E are connected to an external electrode 80, and the second internal electrodes 78A to 78D are connected to another external electrode 82.

本実施例では、前記第１の内部電極７６Ａ〜７６Ｅと、第２の内部電極７８Ａ〜７８Ｄの重なり具合には偏りがなく、シャフト２０が、圧電素子７２の上面の略中央から、＋Ｘ方向にずれている。すなわち、シャフト２０が、圧電素子７２の中心軸に対して、非対称となるように配置されている。以上のような構成の圧電素子７２に、前記実施例１と同様に時間に対して非対称の信号を入力して駆動させると、低電圧でもスライダ２４が速い速度で駆動した。このように、ステータ８４の全体構造を中心軸に対して非対称とすることでも、低電圧で効率的な駆動を行うことができるという効果がある。 In this embodiment, there is no deviation in the overlapping state of the first internal electrodes 76A to 76E and the second internal electrodes 78A to 78D, and the shaft 20 extends from the approximate center of the upper surface of the piezoelectric element 72 in the + X direction. It's off. That is, the shaft 20 is disposed so as to be asymmetric with respect to the central axis of the piezoelectric element 72. When the piezoelectric element 72 configured as described above is driven by inputting an asymmetric signal with respect to time as in the first embodiment, the slider 24 is driven at a high speed even at a low voltage. Thus, even if the overall structure of the stator 84 is asymmetric with respect to the central axis, there is an effect that efficient driving can be performed at a low voltage.

次に、図９を参照しながら、本発明の実施例４を説明する。図９は、本実施例４の全体構成を示す断面図である。本実施例４の駆動装置９０は、上述した実施例３の変形例であって、圧電素子７２の基本的な構造は同じであるが、前記圧電素子７２の両主面には、外部電極を兼ねたシンバル９２及び９６が取り付けられている。なお、図示の例では、シンバル９２及び９６から電極を取り出すこととしたが、前記実施例３と同様の外部電極８０及び８２を設けるようにしてもよい。前記シンバル９２及び９６は、圧電素子７２と接合される側にそれぞれ空洞９４及び９８を有しており、このようなムーニーの構造によって、圧電素子７２の変位を増幅することができる。本実施例の場合では、前記実施例１のほぼ半分の電圧により、スライダ２４を駆動できることが確認された。他の作用・効果は、前記実施例１と同様である。 Next, Embodiment 4 of the present invention will be described with reference to FIG. FIG. 9 is a cross-sectional view illustrating the overall configuration of the fourth embodiment. The driving device 90 according to the fourth embodiment is a modification of the third embodiment described above, and the basic structure of the piezoelectric element 72 is the same. However, external electrodes are provided on both main surfaces of the piezoelectric element 72. Cymbals 92 and 96 which are also used are attached. In the illustrated example, the electrodes are taken out from the cymbals 92 and 96, but external electrodes 80 and 82 similar to those in the third embodiment may be provided. The cymbals 92 and 96 have cavities 94 and 98 on the side to be joined to the piezoelectric element 72, respectively, and the displacement of the piezoelectric element 72 can be amplified by such a Mooney structure. In the case of the present embodiment, it was confirmed that the slider 24 can be driven by almost half the voltage of the first embodiment. Other operations and effects are the same as those of the first embodiment.

なお、本発明は、上述した実施例に限定されるものではなく、本発明の要旨を逸脱しない範囲内において種々変更を加え得ることができる。例えば、以下のものも含まれる。
(1)上述した実施例に示した材料，形状，寸法は一例であり、同様の効果を奏するようにて適宜変更可能である。
(2)前記実施例で示した外部電極や内部電極の配置も一例であり、同様の効果を奏するように適宜設計変更可能である。
(3)積層型の圧電素子の積層構造や電極引き出し構造も一例であり、必要に応じて適宜変更してよい。
(4)前記シャフト２０及び３０も一例であり、円柱状や角柱状としてよい。スライダ２４及び３２も一例であり、前記シャフト２０及び３０に沿って変位できるものであれば、どのような構成のものであってもよい。また、スライダ２４及び３２と、レンズ３４を一体化するような構成としてもよい。
(5)駆動用の印加電圧の波形も、駆動形態に応じて適宜変更してよい。
(6)前記実施例では、一方のシャフトのみを圧電素子に固定する片持ち支持としたが、複数のシャフトを圧電素子に固定する構造としてもよい。
(7)本実施例の駆動装置は一例であり、本発明は、例えば、カメラの撮影レンズやオーバーヘッドプロジェクタなどの投影レンズ，双眼鏡のレンズ，複写機のレンズなど、光学装置におけるレンズの駆動のほか、プロッタやＸ−Ｙ駆動テーブルのような装置など、駆動部を有する装置一般に適用可能である。 In addition, this invention is not limited to the Example mentioned above, A various change can be added in the range which does not deviate from the summary of this invention. For example, the following are also included.
(1) The materials, shapes, and dimensions shown in the above-described embodiments are examples, and can be appropriately changed so as to achieve the same effect.
(2) The arrangement of the external electrode and the internal electrode shown in the above embodiment is also an example, and the design can be changed as appropriate so as to achieve the same effect.
(3) The laminated structure of the laminated piezoelectric element and the electrode lead-out structure are examples, and may be appropriately changed as necessary.
(4) The shafts 20 and 30 are also examples, and may be cylindrical or prismatic. The sliders 24 and 32 are also examples, and may be of any configuration as long as they can be displaced along the shafts 20 and 30. The sliders 24 and 32 and the lens 34 may be integrated.
(5) The waveform of the applied voltage for driving may be appropriately changed according to the driving mode.
(6) In the above-described embodiment, the cantilever support in which only one shaft is fixed to the piezoelectric element is used, but a structure in which a plurality of shafts are fixed to the piezoelectric element may be employed.
(7) The driving device of the present embodiment is an example, and the present invention is not limited to driving lenses in optical devices such as projection lenses such as camera photographing lenses and overhead projectors, binocular lenses, and copier lenses. In addition, the present invention can be applied to a device having a drive unit such as a device such as a plotter or an XY drive table.

本発明によれば、スライダ（ないし被変位体）の移動を軸方向にガイドするシャフトの一端が固定される駆動素子によって、前記シャフトの軸方向及び該軸方向と交わる方向に、前記シャフトを駆動することとした。このため、シャフトとスライダ間の固着力を効率的に切断して、低電圧で安定した変位が可能になることから、安定した動作が必要とされる精密機器や通信機器などで利用される駆動装置の用途に適用できる。特に、小型化，軽量化，薄型化が要求される駆動装置の用途に好適である。 According to the present invention, the shaft is driven in the axial direction of the shaft and in a direction intersecting with the axial direction by a driving element to which one end of the shaft that guides the movement of the slider (or the displaced body) in the axial direction is fixed. It was decided to. For this reason, the fixing force between the shaft and the slider can be cut efficiently to enable stable displacement at a low voltage, so driving used in precision equipment and communication equipment that requires stable operation. Applicable to the use of the device. In particular, it is suitable for the use of a drive device that requires a reduction in size, weight, and thickness.

本発明の実施例１を示す図であり、(A)は駆動装置の全体構成を示す断面図，(B)はシャフト及びスライダを軸上から見た平面図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Example 1 of this invention, (A) is sectional drawing which shows the whole structure of a drive device, (B) is the top view which looked at the shaft and the slider from the axial top. 前記実施例１のステータの振動特性を示す図である。It is a figure which shows the vibration characteristic of the stator of the said Example 1. FIG. 前記実施例１のステータの振動モードのシミュレーション結果である。It is a simulation result of the vibration mode of the stator of Example 1. 前記実施例１のステータの共振周波数と圧電素子サイズの関係を示す図である。It is a figure which shows the relationship between the resonant frequency of the stator of the said Example 1, and a piezoelectric element size. 前記実施例１の圧電素子の変位量と時間の関係を示す図である。It is a figure which shows the relationship between the displacement amount of the piezoelectric element of the said Example 1, and time. 本発明の実施例２の駆動装置の全体構成を示す断面図である。It is sectional drawing which shows the whole structure of the drive device of Example 2 of this invention. 前記実施例２と比較例の駆動装置によるスライダの変位速度と駆動電圧の関係を示す図である。It is a figure which shows the relationship between the displacement speed of the slider by the drive device of the said Example 2 and a comparative example, and a drive voltage. 本発明の実施例３の駆動装置の全体構成を示す断面図である。It is sectional drawing which shows the whole structure of the drive device of Example 3 of this invention. 本発明の実施例４の駆動装置の全体構成を示す断面図である。It is sectional drawing which shows the whole structure of the drive device of Example 4 of this invention. 背景技術の一例を示す図である。It is a figure which shows an example of background art.

Explanation of symbols

１０：駆動装置（アクチュエータ）
１２：圧電素子
１４：圧電体
１６，１８：外部電極
２０，３０：シャフト
２２：ステータ
２４，３２：スライダ
２４Ａ，２４Ｂ：分割体
２６：付勢手段
３４：レンズ
５０：駆動装置
５２：圧電素子
５４：圧電体
５６Ａ〜５６Ｅ，５８Ａ〜５８Ｄ：内部電極
６０，６２：外部電極
６４：ステータ
７０：駆動装置
７２：圧電素子
７４：圧電体
７６Ａ〜７６Ｅ，７８Ａ〜７８Ｄ：内部電極
８０，８２：外部電極
８４：ステータ
９０：駆動装置
９２，９６：シンバル
９４，９８：空洞
１００：圧電素子
１０２：シャフト
１０４：スライダ
１０６：レンズ
１０８：本体
10: Drive device (actuator)
12: Piezoelectric element 14: Piezoelectric body 16, 18: External electrode 20, 30: Shaft 22: Stator 24, 32: Slider 24A, 24B: Split body 26: Energizing means 34: Lens 50: Drive device 52: Piezoelectric element 54 : Piezoelectric bodies 56A to 56E, 58A to 58D: Internal electrodes 60, 62: External electrodes 64: Stator 70: Drive device 72: Piezoelectric element 74: Piezoelectric bodies 76A to 76E, 78A to 78D: Internal electrodes 80, 82: External electrodes 84: Stator 90: Drive device 92, 96: Cymbals 94, 98: Cavity 100: Piezoelectric element 102: Shaft 104: Slider 106: Lens 108: Body

Claims

A drive element that is partially fixed and vibrates with applied voltage,
A shaft having one end connected to a portion other than the fixed portion of the drive element;
A slider movable in the axial direction of the shaft by utilizing friction and inertial force with the shaft;
With
The drive device, wherein the drive element is capable of vibrating the shaft in a direction crossing the axial direction of the shaft and the axial direction.

2. The driving apparatus according to claim 1, further comprising an urging unit that urges the slider with respect to the shaft.

The drive element has a structure including external electrodes on both main surfaces of the piezoelectric body,
The shaft is attached to one main surface side of both main surfaces provided with the external electrodes ,
2. The drive device according to claim 1 , wherein a central axis of the shaft is arranged to be shifted from a center of the external electrode .

The drive element is, have a structure inside the first and second internal electrodes are alternately stacked piezoelectric in the axial direction of the shaft connected, and the main surface of the piezoelectric body or Rutotomoni comprising a first external electrode and second external electrode on the end face,
The first internal electrode is connected to the first external electrode, the second internal electrode is connected to the second external electrode;
2. The driving device according to claim 1 , wherein a central axis of the shaft is arranged to be deviated from a center of an overlapping portion of the first internal electrode and the second internal electrode.

The drive device according to claim 1, wherein the drive element vibrates symmetrically with respect to a central axis, and the shaft is arranged to be shifted from the central axis.

The drive device according to claim 1, wherein a rectilinear vibration along the axial direction of the shaft and a bending vibration in a direction intersecting with the axial direction are resonated.

The drive device according to claim 1, further comprising an amplifying unit that amplifies vibration of the drive element.

A driving element for fixing one end of a shaft to which a slider movable in the axial direction is attached,
With external electrodes on both main surfaces of the piezoelectric body,
The shaft is attached to one main surface side of the main surfaces provided with the external electrodes,
The drive element according to claim 1, wherein a central axis of the shaft is arranged to be shifted from a center of the external electrode .

A driving element for fixing one end of a shaft to which a slider movable in the axial direction is attached,
Said first and second internal electrodes in the axial direction fixed by a shaft inside the piezoelectric body to have a structure obtained by stacking alternately, and first on the principal surface or the end surface of the piezoelectric Rutotomoni an external electrode and second external electrodes,
The first internal electrode is connected to the first external electrode, the second internal electrode is connected to the second external electrode;
The drive element according to claim 1 , wherein a central axis of the shaft is shifted from a center of an overlapping portion of the first internal electrode and the second internal electrode.

The drive element according to claim 8 or 9, wherein a part thereof is fixed,
A shaft having one end connected to a portion other than the fixed portion of the drive element;
A slider movable in the axial direction of the shaft by utilizing friction and inertial force with the shaft;
With
A drive device that vibrates the shaft in a direction crossing the axial direction of the shaft and the axial direction by applying a voltage to the drive element.