JP2006042531A - Electrostatic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic actuator capable of driving a moving element by the amount of a half pitch of a drive electrode in one step and smoothly driving the moving element. <P>SOLUTION: This actuator includes a stator 102 having the band-shaped driving electrode 105 periodically disposed, the moving element 101 having a periodical potential distribution at a portion facing the driving electrode 105, and a control section which relatively displaces the stator 102 and the moving element 101 by repeating withdrawal of a prescribed portion of the moving element 101 into a portion facing an intermediate portion of the two driving electrodes 105 next to each other by applying a voltage for activating an electrostatic attracting force between the prescribed portion of the moving element 101 and the two adjacent driving electrodes 105 next to each other, and withdrawal of the prescribed portion of the moving element 101 into a portion facing the one adjacent driving electrode 105 by applying a voltage for activating the electrostatic attracting force between the prescribed portion of the moving element 101 and the one adjacent one driving electrode 105. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrostatic actuator that moves a mover by electrostatic force acting between a stator and a mover, and more particularly to an electret electrostatic actuator that uses an electret for the mover.

  At present, the practical application of a scanning electrostatic actuator capable of efficient driving with a simple configuration is expected. In particular, electret electrostatic actuators that use electrets for the mover do not require wiring to the mover and can be driven at a relatively low voltage. Has been.

  Conventionally, devices shown below are known as electret electrostatic actuators (see Patent Document 1). This will be briefly described with reference to FIG. First, the electret 12 of the mover 10 is set so as to be positioned immediately above a predetermined stator electrode 16 of the stator 14. Here, when the voltages applied to the terminals A to C of the stator electrode 16 are all negative, electric lines of force are generated from the mover 10 side to the stator 14 side, and the mover 10 is attracted to the stator 14. (State (a)). Next, a positive voltage is applied to the A terminal, a negative voltage is applied to the B terminal, and a zero potential is applied to the C terminal, and electric lines of force are formed from the A terminal electrode side to the adjacent B terminal electrode side (state (b)). ). As a result, the positive charge of the electret 12 receives a force along the lines of electric force, rises, and moves to the right by one electrode pitch (state (c)). Next, all the stator electrodes 16 are set to a negative potential, electric lines of force are formed, and the mover 10 is attracted to the stator 14 (state (d)). By repeating this process, the mover 10 can be continuously displaced.

  Moreover, the apparatus shown below is known as an electrostatic actuator which does not use an electret (refer patent document 2). This will be briefly described with reference to FIG. The device is an electrostatic actuator in which a movable element 10 having three electrode strips 18a to 18c formed as drive electrodes moves relative to a stator 14 made of a high-resistance dielectric. This is an electrostatic actuator of a type that generates an electrostatic force between the moving element 10 and the stator 14 by inducing electric charges at a corresponding portion of the stator 14 by a high voltage applied to 18c.

  As shown in FIG. 8, in the initial state (state (a)), no voltage is applied to the strip electrodes 18a to 18c. That is, neither the mover 10 nor the stator 14 is charged at all.

  Next, when a positive high voltage is applied to the strip electrode 18a, a negative high voltage to the strip electrode 18b, and a negative high voltage to the strip electrode 18c through a relay switch (not shown) from a power source (not shown), As shown in the state (b), each of the strip electrodes 18a to 18c is charged in accordance with the applied voltage value, and the stator 14 made of a high-resistance element has the strip electrodes 18a, 18b, and 18c composed of these three electrodes. The position opposite to is dielectrically charged. That is, the position facing the strip electrode 18a is negatively charged, the position facing the strip electrode 18b is positive, and the position facing the strip electrode 18c is positively charged.

  In such a state (state (b)), the relay switch is operated by a control unit (not shown) such as a personal computer to switch the voltage applied to the strip electrodes 18a to 18c. For example, when a negative high voltage is applied to the strip electrode 18a, a negative high voltage is applied to the strip electrode 18b, and a positive high voltage is applied to the strip electrode 18c, the operation is instantaneously applied to the strip electrodes 18a to 18c. Charges are generated according to the applied voltage. On the other hand, since the stator 14 is composed of a high resistance layer, the internal charges cannot move instantaneously, and the charged state is maintained in the previous operation (state (c)). In this state (c), the following electrostatic force acts between the mover 10 and the stator 14. The strip electrode 18a receives a repulsive force from the stator 14 at the opposite position, and receives a suction force from a position facing the strip electrode 18b. That is, the belt-like electrode 18a is acted upon by a force that causes the belt to float from the stator 14 and to drive to the right. A repulsive force acts on the strip electrode 18b from a position facing the strip electrode 18a, an attraction force from a position facing the strip electrode 18b, and an attracting force from a position facing the strip electrode 18c. That is, as a total, a force attracted to the stator 14 and a rightward driving force act on the strip-shaped electrode 18b. The strip electrode 18c receives a repulsive force from a position facing the strip electrode 18b and a position facing the strip electrode 18c, and generates a force to float from the stator 14.

  The moving element 10 is moved by one pitch of the strip electrodes 18a to 18c and stopped by the driving force due to the electrostatic force (state (d)). In this state (d), the electrostatic force is balanced, and the mover 10 is attracted to the stator 14. Furthermore, the position facing the strip electrode 18c in this state is newly negatively dielectrically charged.

By repeating the above operation, the mover 10 continues to move on the stator 14. At that time, a driving force corresponding to the magnitude of the high voltage applied from the power source (not shown) is generated in the moving element 10. The mover 10 moves at a speed corresponding to the switching speed of a relay switch (not shown). The mover 10 can move within the range of the size of the stator 14.
Japanese Patent Laid-Open No. 4-112683 JP-A-6-225549

  In the techniques disclosed in Patent Documents 1 and 2, the displacement amount of the moving element 10 is basically determined by the number of pulses applied to the drive electrodes 16 and 18a to 18c, so that position control in an open loop is possible. However, since the displacement step is equal to the pitch of the strip-like drive electrodes 16, 18a to 18c, it is necessary to make the pitch of the strip-like drive electrodes fine for smooth operation. However, an electrode with a narrow pitch is not so desirable because it has difficulty in manufacturing technology and also causes a decrease in dielectric strength.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an electrostatic actuator for realizing smoother driving without reducing the pitch of the belt-like drive electrodes.

  According to a first aspect of the electrostatic actuator of the present invention, there is provided a first substrate having strip-shaped drive electrodes arranged periodically, and a periodic potential distribution at a predetermined portion of the first substrate facing the drive electrodes. In the electrostatic actuator that relatively displaces the second substrate having the above, an electrostatic attraction force is generated between the predetermined portion of the second substrate and the two drive electrodes of the first substrate adjacent in the vicinity thereof. A voltage to be applied is applied to the drive electrode, and the predetermined portion of the second substrate is drawn into a portion facing an intermediate portion of the two adjacent drive electrodes; A voltage that causes an electrostatic attraction force to act between the predetermined portion and one drive electrode of the first substrate in the vicinity thereof is applied to the drive electrode, and the predetermined portion of the second substrate is moved to the predetermined position. Pull it to the part facing the one drive electrode in the vicinity. And Mukoto, by repeating, characterized by comprising a driving control means for relative displacement between the first substrate and the second substrate.

  Further, the second aspect of the electrostatic actuator of the present invention is such that the first substrate having the strip-shaped drive electrodes arranged periodically and the portion of the first substrate facing the drive electrodes are periodically formed. In the electrostatic actuator for relatively displacing the second substrate having the electret region having the predetermined charge amount, the first substrate adjacent to the electret region of the second substrate in the vicinity thereof. A voltage that causes an electrostatic attraction force to act between the two drive electrodes is applied to the drive electrode so that the electret region is located at a portion facing the intermediate portion of the two adjacent drive electrodes. A voltage that causes an electrostatic attraction force to act on the drive electrode between the electret region of the second substrate and the one drive electrode of the first substrate in the vicinity thereof. mark And a drive control means for relatively displacing the first substrate and the second substrate by repeatedly drawing the electret region into a portion facing the one drive electrode. It is characterized by doing.

  According to a third aspect of the electrostatic actuator of the present invention, a first substrate having a drive electrode composed of a plurality of phases, and a portion disposed on the first substrate and facing the drive electrode. The electretized region on the second substrate is composed of only one phase of the second substrate that periodically has electretized regions of a predetermined charge amount and the drive electrode on the first substrate. An electrostatic attraction force is applied to the drive electrode to draw the electret region directly above the drive electrode, and the electret on the second substrate is in two adjacent phases of the drive electrode on the first substrate. A drive pattern is generated in which an electrostatic attraction force is applied to the converted region, and the electret region is drawn directly above the intermediate portion between the adjacent drive electrodes. And, provided with a drive control unit for applying to the driving electrodes of said first substrate, said second substrate is characterized by a relative displacement of half a pitch step to the first substrate.

  According to the present invention, since the movable element can be driven by a half pitch of the belt-like drive electrode in one step, the movable body can be driven more smoothly without reducing the pitch of the belt-like drive electrode. An electric actuator can be provided.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram showing the structure of the electrostatic actuator according to the present embodiment. As shown in the figure, the moving element 101 is arranged on the upper part of the stator 102. Here, the moving element 101 can be displaced in the arrow direction in the figure with respect to the stator 102.

  FIG. 2 is a diagram showing the electrostatic actuator according to the present embodiment shown in FIG. 1 separated into a movable element 101 and a stator 102 for ease of explanation.

  As shown in the figure, the mover 101 is an electret film in which a negatively charged belt-like region (hereinafter referred to as a charged region) 104 is periodically provided on a fluororesin film 103.

  The stator 102 has a structure in which a drive electrode 105 (metal electrode) is formed on a glass substrate. The drive electrode 105 has a strip shape, and is formed on the surface side of the stator 102 (the side on which the mover 101 is disposed).

  Further, drive wirings 108, 109, 110, and 111 are formed on the back side of the stator 102 (the side on which the mover 101 is not disposed). As shown in FIG. 3, these drive wirings 108, 109, 110, and 111 are electrically connected to the drive electrode 105 through contact holes 107. This electrical connection is made in four cycles. That is, the drive wirings 108, 109, 110, and 111 are connected to a four-phase pulse power source. Although not particularly illustrated, the drive wirings 108, 109, 110, and 111 and sensing wiring (not shown) are connected to an external circuit via lead wires.

  FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2. As shown in the figure, the charging region 104 of the moving element 101 is formed with a period corresponding to four driving electrodes 105 of the stator 102.

  FIG. 4 is a diagram schematically showing the connection of the electrodes of the electrostatic actuator. As shown in the figure, the drive electrode 105 of the stator 102 is connected to the wiring of each phase of A, B, C, and D, and each of these phases A, B, C, and D is used as a four-phase pulse power source. Connected. Here, the wiring of each phase of A, B, C, and D corresponds to the wiring connected to the driving wirings 108, 109, 110, and 111, respectively.

  Hereinafter, the operation of the electrostatic actuator according to the present embodiment will be described with reference to FIGS. 5 and 6.

  FIG. 5 is a diagram showing drive pulses applied to the respective phases A, B, C, and D from the four-phase pulse power source in order to displace the mover 101.

  Here, the voltage of each phase takes a positive or negative binary value. As shown in the figure, at time t1, only the A phase is positive and the others are negative. At the subsequent time t2, only the A and B phases are positive and the others are negative. At the subsequent time t3, only the B phase is positive and the others are negative. At the subsequent time t4, only the B and C phases are positive and the others are negative. At the subsequent time t5, only the C phase is positive and the others are negative.

  Hereinafter, the operation of the mover 101 at times t1 to t5 shown in FIG. 5 will be described with reference to FIG.

  First, at time t1, a positive voltage is applied only to the electrode corresponding to the A phase in the drive electrode 105, and a negative voltage is applied to the other electrodes. For this reason, the negatively charged region 104 of the moving element 101 is drawn into a portion corresponding to the A phase of the drive electrode 105. At a subsequent time t2, since a positive voltage is applied only to the electrodes corresponding to the A and B phases, the charging region 104 is drawn into a portion of the drive electrode 105 corresponding to the middle between the A and B phases. Similarly, at times t3 and t4, the charging region 104 is drawn into a portion corresponding to the B phase of the drive electrode 105 and a portion corresponding to the middle between the B phase and the C phase. At time t <b> 5, the charged region 104 is drawn into a portion corresponding to the C phase of the drive electrode 105.

  Similarly, by applying a driving pulse as shown in FIG. 5, the movable element 101 can be continuously displaced by a half pitch of the driving electrode.

  As described above, in this embodiment, an electrostatic attraction force is applied to the charging region 104 of the moving element 101 with only one phase of the driving electrode 105 of the stator 102, and the driving electrode 105 is directly above the driving electrode 105. The process of drawing the charging area 104 and the electrostatic attraction force acting on the charging area of the moving element in the two adjacent phases of the driving electrode 105 in the stator 102, immediately above the intermediate portion between the adjacent driving electrodes 105. By repeating the process of pulling in the charging area 104, it is possible to realize smooth driving of the moving element 101 in a half pitch step.

  In the present embodiment, the drive electrode 105 has four phases, but it goes without saying that the present invention can be similarly applied to three phases, five phases, or more.

  Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are naturally possible within the scope of the gist of the present invention.

(Appendix)
The invention having the following configuration can be extracted from the specific embodiment.

(1) Relative displacement of a first substrate having a belt-like drive electrode arranged periodically and a second substrate having a periodic potential distribution at a predetermined portion of the first substrate facing the drive electrode In the electrostatic actuator to be
A voltage that causes an electrostatic attraction force to act between the predetermined portion of the second substrate and the two drive electrodes of the first substrate adjacent in the vicinity thereof is applied to the drive electrode. Drawing the predetermined part of the two substrates into a part facing the intermediate part of the two adjacent drive electrodes;
A voltage that causes an electrostatic attraction force to act between the predetermined portion of the second substrate and one drive electrode of the first substrate in the vicinity thereof is applied to the drive electrode, Drawing the predetermined portion of the substrate into a portion facing the one drive electrode in the vicinity thereof;
An electrostatic actuator comprising drive control means for relatively displacing the first substrate and the second substrate by repeating the above.

(Corresponding embodiment)
The embodiment relating to the electrostatic actuator described in (1) corresponds to one embodiment. In the embodiment, the drive electrode corresponds to, for example, the drive electrode 105, the first substrate corresponds to, for example, the stator 102, the second substrate corresponds to, for example, the mover 101, and the predetermined portion is For example, a negatively charged band-shaped charging region 104 corresponds, and the drive control unit corresponds to, for example, a four-phase pulse power source.

(Function and effect)
The electrostatic actuator described in (1) is a process in which only one phase of the driving electrode in the stator causes an electrostatic attraction force to act on the charging area of the moving element, and the charging area is drawn directly above the driving electrode. And a process of pulling the charging area directly above the intermediate portion between the adjacent driving electrodes by applying an electrostatic attraction force to the charging area of the moving element in the two adjacent phases of the driving electrode in the stator. By repeating, it is possible to realize smooth drive of the half pitch step.

Therefore, according to the electrostatic actuator described in (1), it is possible to provide an electrostatic actuator that can smoothly drive the moving element without reducing the pitch of the drive electrodes. (2) Periodically arranged Relative displacement between the first substrate having a strip-shaped drive electrode and the second substrate having a region electretized to a predetermined charge amount periodically at a portion of the first substrate facing the drive electrode In the electrostatic actuator
A voltage that causes an electrostatic attraction force to act between the electretized region of the second substrate and the two drive electrodes of the first substrate adjacent in the vicinity thereof is applied to the drive electrode. Pulling the electretized region into a portion facing the intermediate portion of the two adjacent drive electrodes;
A voltage that causes an electrostatic attraction force to act between the electretized region of the second substrate and one drive electrode of the first substrate in the vicinity thereof is applied to the drive electrode, Drawing the electretized region into a portion facing the one drive electrode;
An electrostatic actuator comprising drive control means for relatively displacing the first substrate and the second substrate by repeating the above.

(Corresponding embodiment)
One embodiment corresponds to the embodiment relating to the electrostatic actuator described in (2). In the one embodiment, the drive electrode corresponds to, for example, the drive electrode 105, the first substrate corresponds to, for example, the stator 102, and the second substrate corresponds to, for example, the mover 101, and is converted into the electret. For example, the negatively charged band-shaped charging area 104 corresponds to the area, and the drive control means corresponds to, for example, a four-phase pulse power source.

(Function and effect)
The electrostatic actuator described in (2) is a process in which only one phase of the driving electrode in the stator causes an electrostatic attraction force to act on the charging area of the moving element, and the charging area is drawn directly above the driving electrode. And a process of pulling the charging area directly above the intermediate portion between the adjacent driving electrodes by applying an electrostatic attraction force to the charging area of the moving element in the two adjacent phases of the driving electrode in the stator. By repeating, it is possible to realize smooth drive of the half pitch step.

  Therefore, according to the electrostatic actuator described in (2), it is possible to provide an electrostatic actuator that can smoothly drive the moving element without reducing the pitch of the drive electrodes.

(3) a first substrate having a drive electrode composed of a plurality of phases;
A second substrate that is disposed on the first substrate and periodically has areas electretized to a predetermined charge amount at a portion facing the drive electrode;
With only one phase of the drive electrode on the first substrate, an electrostatic attraction force is applied to the electret region on the second substrate, and the electret region is directly above the drive electrode. Pulling and applying an electrostatic attraction force to the electret region of the second substrate in the two adjacent phases of the drive electrode of the first substrate, so that the intermediate between the adjacent drive electrodes Drive control means for generating a drive pattern that repeats drawing the electret region directly above the part and applying the drive pattern to the drive electrode of the first substrate, and An electrostatic actuator, wherein the substrate is displaced relative to the first substrate by a half pitch step.

(Corresponding embodiment)
The embodiment relating to the electrostatic actuator described in (3) corresponds to one embodiment. In the one embodiment, the drive electrode corresponds to, for example, the drive electrode 105, the first substrate corresponds to, for example, the stator 102, and the electret region includes, for example, a negatively charged belt-like charged region 104 Correspondingly, the second substrate corresponds to, for example, the moving element 101, and the drive control means corresponds to, for example, a four-phase pulse power source.

(Function and effect)
The electrostatic actuator described in (3) is a process in which only one phase of the driving electrode in the stator causes an electrostatic attraction force to act on the charging area of the moving element, and the charging area is drawn directly above the driving electrode. And a process of pulling the charging area directly above the intermediate portion between the adjacent driving electrodes by applying an electrostatic attraction force to the charging area of the moving element in the two adjacent phases of the driving electrode in the stator. By repeating, it is possible to realize smooth drive of the half pitch step.

  Therefore, according to the electrostatic actuator described in (3), it is possible to provide an electrostatic actuator that can smoothly drive the moving element without reducing the pitch of the drive electrodes.

It is a figure which shows the structure of the electrostatic actuator which concerns on one Embodiment of this invention. It is the figure which isolate | separated and showed the electrostatic actuator which concerns on one Embodiment to the slider and the stator. FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2. It is the figure which showed typically about the connection of the electrode of the actuator which concerns on one Embodiment. It is a figure which shows the drive pulse for displacing a slider. It is the figure shown about operation | movement of the electrostatic actuator of one Embodiment. It is a figure which shows the prior art of patent document 1. FIG. It is a figure which shows the prior art described in patent document 2.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 101 ... Motor, 102 ... Stator, 103 ... Fluororesin film, 104 ... Negatively charged belt-like region (charging region), 105 ... Driving electrode, 107 ... Contact hole, 108, 109, 110, 111 ... Driving wiring .

Claims (3)

An electrostatic force that relatively displaces a first substrate having a belt-like drive electrode arranged periodically and a second substrate having a periodic potential distribution at a predetermined portion of the first substrate facing the drive electrode. In the actuator
A voltage that causes an electrostatic attraction force to act between the predetermined portion of the second substrate and the two drive electrodes of the first substrate adjacent in the vicinity thereof is applied to the drive electrode. Drawing the predetermined part of the two substrates into a part facing the intermediate part of the two adjacent drive electrodes;
A voltage that causes an electrostatic attraction force to act between the predetermined portion of the second substrate and one drive electrode of the first substrate in the vicinity thereof is applied to the drive electrode, Drawing the predetermined portion of the substrate into a portion facing the one drive electrode in the vicinity thereof;
An electrostatic actuator comprising drive control means for relatively displacing the first substrate and the second substrate by repeating the above. A first substrate having a belt-like drive electrode arranged periodically; and a second substrate having a region electretized to a predetermined charge amount periodically at a portion of the first substrate facing the drive electrode. In the electrostatic actuator that relatively displaces the substrate,
A voltage that causes an electrostatic attraction force to act between the electretized region of the second substrate and the two drive electrodes of the first substrate adjacent in the vicinity thereof is applied to the drive electrode. Pulling the electretized region into a portion facing the intermediate portion of the two adjacent drive electrodes;
A voltage that causes an electrostatic attraction force to act between the electretized region of the second substrate and one drive electrode of the first substrate in the vicinity thereof is applied to the drive electrode, Drawing the electretized region into a portion facing the one drive electrode;
An electrostatic actuator comprising drive control means for relatively displacing the first substrate and the second substrate by repeating the above. A first substrate having a drive electrode composed of a plurality of phases;
A second substrate that is disposed on the first substrate and periodically has areas electretized to a predetermined charge amount at a portion facing the drive electrode;
With only one phase of the drive electrode on the first substrate, an electrostatic attraction force is applied to the electret region on the second substrate, and the electret region is directly above the drive electrode. Pulling and applying an electrostatic attraction force to the electret region of the second substrate in the two adjacent phases of the drive electrode of the first substrate, so that the intermediate between the adjacent drive electrodes Drive control means for generating a drive pattern that repeats drawing the electretized region directly above the portion and applying the drive pattern to the drive electrode of the first substrate;
The electrostatic actuator is characterized in that the second substrate makes a half-pitch step relative displacement with respect to the first substrate.

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