JP2005333755A - Electrostatic attraction driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic attraction driver arranged to generate a big driving force while reducing the size. <P>SOLUTION: A plurality of stator side electrodes 23 provided in the stator 20 and a plurality of mover side electrodes 33 provided in the mover 30 are arranged oppositely while projecting in the vertical direction. Since a three-dimensionally wide opposing area can be secured between the stator side electrode 23 and the mover side electrode 33 even in a limited space, big electrostatic attraction can be generated between both electrodes and the mover 30 can be driven with a big driving force. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrostatic attraction driving device driven by an electrostatic force, and more particularly to an electrostatic attraction driving device capable of generating a large thrust by obtaining a larger electrostatic force (Coulomb force).

  As a prior art document related to a conventional electrostatic attraction drive device, for example, the following Patent Document 1 exists. FIG. 10 is a diagram showing a schematic configuration of the electrostatic attraction drive device shown in FIG. 1 of Patent Document 1, and FIG. 11 is a timing chart showing electric signals applied to the electrodes as in FIG.

  In this electrostatic attraction drive device, as shown in FIG. 10, the first stator 2a and the second stator 2b are arranged to face each other with a predetermined distance therebetween, and the mover 3 that slides between them. Is arranged.

  The first stator 2a is provided with three systems of electrodes A, B and C (first electrodes) sequentially arranged in a predetermined direction, and the second stator 2b is provided with a uniform system of electrodes. D is provided. The mover 3 includes an electrode portion 3a provided on one surface corresponding to the electrode pitch of each electrode A, B, C of the first stator 2a, and the second fixed on the other surface. A flat electrode portion 3d provided to face the child 2b, and both the electrode portions 3a and 3d form one system of electrodes E (third electrode) maintained at the same potential. .

As shown in FIG. 11, when a voltage is applied to the electrode A provided on the first stator 2a and the potential of the electrode A is made higher than the potential of the electrode E provided on the mover 3, the electrode A and the electrode The mover 3 is attracted to the first stator 2a side by an electrostatic force (Coulomb force) acting with E. At this time, since the state in which the electrode A and the electrode portion 3a are exactly overlapped is most stable, the movable element 3 receives an acting force from the electrode A so that the electrode A and the electrode portion 3a overlap. Subsequently, when the electrode to which the voltage is applied is switched to the electrode D provided on the second stator 2b, the mover 3 is attracted to the second stator 2b side. Further, when the electrode to which the voltage is applied is switched to the electrode B provided on the stator 2a, the movable element 3 is arranged so that the electrode B and the electrode portion 3a overlap each other by the same mechanism as when the voltage is applied to the electrode A. Receives more force. A series of such operations, that is, a voltage is repeatedly applied from the voltage source 6 through the switching circuit 5 in the order of electrode A → electrode D → electrode B → electrode D → electrode C → electrode D → electrode A. A voltage is applied alternately to the electrodes A to C provided on the stator 2a and the electrode D provided on the second stator 2b, and the electrodes provided on the first stator 2a are sequentially switched in the predetermined direction. Thus, the movable element 3 is driven in the arrangement direction (right side in the drawing) of the electrodes arranged on the first stator while macroscopically vibrating vertically. Yes.
JP 2001-346385 A

  When the electrostatic suction driving device as described above is mounted on, for example, a camera and used as a driving device for moving a lens for autofocus, obtaining a driving force for moving the lens, and It is necessary to increase the moving speed and response speed at that time. For this purpose, it is necessary to provide an electrostatic attraction drive device that can obtain a large driving force by generating a large electrostatic force (Coulomb force).

  Here, the electrostatic force generally has a property of being proportional to the square of the applied voltage and the opposing area between the electrodes and inversely proportional to the square of the gap dimension of the gap. Therefore, a large electrostatic force can be obtained by setting these elements to optimum values.

  However, in order to increase the applied voltage, there are limitations due to problems such as a battery that can be mounted on the camera and withstand voltage. In addition, there is a limit to narrowing the gap size due to problems in machining accuracy.

  The conventional electrostatic attraction drive device has a configuration in which the electrodes on the first and second stators 2a and 2b side and the electrode on the movable element 3 side face each other. For this reason, in order to increase the facing area between the electrodes, it is necessary to increase the area of each electrode provided on the first stator 2a, the second stator 2b, and the mover 3 in a plane. However, in that case, the electrostatic attraction drive device itself becomes large. In addition, since the weight of the mover 3 also increases, there is a problem that the moving speed and response speed of the mover 3 are lowered.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide an electrostatic attraction drive device that can be miniaturized and can generate a large driving force.

An electrostatic attraction drive device according to the present invention includes a stator extending along a moving direction, a mover disposed to face the stator, and a stator provided on the stator and facing the mover. A stator side electrode protruding perpendicularly to the mover direction from the facing surface and aligned in the moving direction, and the stator from the mover facing surface provided on the mover side and facing the stator facing surface A mover side electrode that projects perpendicularly to the direction and is aligned with respect to the moving direction;
The stator side electrode and the mover side electrode are arranged to face each other in a width direction perpendicular to the moving direction and perpendicular to the direction in which the opposing surfaces are opposed to each other, and the stator side electrode The mover is moved in the moving direction by an electrostatic attraction force generated at a portion facing the mover side electrode.

  In the above, a plurality of stator side electrodes are regularly arranged at predetermined intervals along the moving direction and the width direction on the facing surface on the stator side, and a plurality of movable electrodes are disposed on the facing surface on the mover side. It is preferable that the child side electrode is regularly arranged at a position where it does not overlap with the stator side electrode.

  In the electrostatic attraction drive device of the present invention, since the plurality of mover side electrodes and the plurality of stator side electrodes are arranged to face each other in a three-dimensional manner, a wide facing area can be secured between the electrodes. Electrosuction force can be increased. For this reason, it becomes possible to obtain a large propulsive force, and it becomes possible to convey a heavy object more than before.

  For example, a plurality of electrode groups formed by conducting and connecting a plurality of the stator side electrodes arranged in the width direction are arranged in parallel in the movement direction so that two or more phases of electrical signals are individually transmitted. The movable member can be driven by being provided to the electrode group.

  The mover is preferably grounded via a predetermined resistor, and more preferably, the state of electrical connection between the mover and the ground potential is switched at a predetermined timing. .

  Since the above means can release a charge that is easily charged to the movable element side, the movement of the movable element can be made agile. That is, the moving speed and response speed of the mover can be increased.

  In the present invention, it is possible to provide an electrostatic attraction drive device capable of exerting a large driving force by obtaining a large electrostatic attraction force. Therefore, it becomes possible to carry a heavy article compared with the past.

  Further, by removing the charge of the mover at a predetermined timing, it is possible to prevent a decrease in the moving speed and response speed of the mover.

  FIG. 1 is an exploded perspective view showing an electrostatic attraction drive device as an embodiment of the present invention, FIG. 2 shows a state in which a stator and a mover face each other, and a sectional view taken along line II-II in FIG. It is. FIG. 3 is a plan view partially showing the structure of the stator as the first embodiment, and FIG. 4 is a cross-sectional view showing one structure of the stator and the substrate to which the stator is attached. In the following, the Y1 direction shown in the figure is the moving direction, the X direction is the width direction, and the Z direction is the height direction.

  As shown in FIG. 1, the electrostatic attraction drive device 10 of the present invention has a stator 20 provided on the Z2 side in the drawing in the height direction and a mover 30 provided on the Z1 side in the drawing. .

  The stator 20 is a flat plate-like member extending in the Y direction that is the moving direction, and is formed of an insulating material such as silicon. At both ends in the width direction (X direction) of the facing surface (stator side facing surface) 20a (Z1 side) of the stator 20, a pair of V-shapes extending parallel to each other along the moving direction (Y direction). Guide grooves 21 and 21 are provided. The surfaces of the guide grooves 21 and 21 are formed as smooth surfaces having a small frictional resistance.

  On the other hand, the length of the mover 30 in the movement (Y) direction is shorter than that of the stator 20. The mover 30 is made of a conductive material. Alternatively, a conductive plate or the like may be attached to one surface of the mover 30 formed of an insulating material such as silicon to form a facing surface (movable side facing surface) 30a.

  At both ends in the width direction (X direction) on the facing surface 30a (Z2) side of the mover 30, a pair of guide convex portions 31, 31 extending in parallel with each other along the moving direction (Y direction) are provided. Yes. The surfaces of the guide protrusions 31, 31 are also formed as smooth surfaces with small frictional resistance.

  As shown in FIG. 2, when the facing surface 20a of the stator 20 and the facing surface 30a of the mover 30 are made to face each other, the guide convex portions 31 and 31 are fitted into the guide grooves 21 and 21, respectively. The electrostatic suction driving device 10 is assembled. When a force in the moving direction is applied to the mover 30 in this state, the mover 30 can be moved linearly in the Y direction (moving direction). That is, the guide grooves 21 and 21 and the guide convex portions 31 and 31 in this embodiment function as guide means for guiding the mover 30 in the moving direction.

  As shown in FIG. 1, a plurality of flat stator side electrodes 23 are provided on the facing surface 20 a of the stator 20. The stator side electrode 23 is formed by plating and growing a conductive metal such as copper perpendicular to the Z direction. The direction of the stator side electrode 23 is formed so that the direction along the wide electrode surface is parallel to the movement (Y) direction, that is, the electrode surface is perpendicular to the width direction. Yes. Such a plurality of stator side electrodes 23 are regularly arranged at equal intervals on the facing surface 20a along the moving direction and the width direction.

  In the embodiment shown in FIG. 3, the stator side electrodes 23 formed in six columns in the X direction (width direction) are formed in N rows with a predetermined interval in the Y direction (movement direction). Note that the arrangement of the stator side electrodes 23 is not limited to the N rows and 6 columns as described above, and may be arranged more or less.

  In the first embodiment shown in FIG. 3, a plurality of conductive portions 24 extending in the X direction shown in the figure are formed in N rows in the Y direction on the opposing surface 20a of the stator 20, that is, on the base of the stator side electrode 23. Each of the conductive portions 24 is formed with an electrode group in which six (six columns) stator side electrodes 23 are connected in a conductive manner so as to have the same potential for each row. However, the conductive portions 24 adjacent to each other in the moving direction (Y) direction are disconnected, and the electrode groups are electrically insulated from each other. And each said electroconductive part 24 is withdraw | derived to the exterior of the stator 20 for every electrode group, and a voltage is applied for every electrode group.

  For example, as shown in FIGS. 2 and 3, the through holes 25 penetrating the stator 20 in the height direction are formed in N rows in the Y direction, and the through holes 25 are formed. The lead conductive portions 24 a extending from the respective conductive portions 24 via the respective conductive portions 24 may be pulled out to the lower surface (the Z2 side surface) of the stator 20. In this case, each of the conductive portions 24 is connected to the outside of the stator 20 via a plurality of conductive pads 26a, 26b,... (See FIG. 4) formed corresponding to the lower surface of the stator 20 for each row. It is possible to pull out.

  Further, as shown in FIG. 4, it is preferable that a substrate 40 having a multilayer structure for fixing the stator 20 is provided below the stator 20. On the substrate 40, a plurality of conductive connection pads 41a, 41b,... Corresponding to the conductive pads 26a, 26b,. Therefore, the stator 20 is pressed against the substrate 40 and the conductive pads 26a, 26b,... Are pressed to the connection pads 41a, 41b,. The conductive pads 26a, 26b, ... are electrically connected to the connection pads 41a, 41b, ... by providing a conductive adhesive between the pads 41a, 41b, .... Becomes easy.

  A plurality of through holes 42 extending in the plate thickness (Z) direction and a plurality of conductive layers 43 extending in the moving direction are formed in the substrate 40, and each of the connection pads 41a, 41b,. The hole 42 and the conductive layer 43 can be connected. For example, in the embodiment shown in FIG. 4, the connection pads 41a, 41e, 41i are connected to the through holes 42a, 42b, 42c via the conductive layer 43a. Similarly, the connection pad 41b and the connection pad 41f are connected, the connection pad 41c and the connection pad 41g are connected, and the connection pad 41d and the connection pad 41h are connected. Therefore, in the stator 20, for example, one electrode group connected to the conductive pad 26a is electrically connected to one electrode group connected to the conductive pad 26e and one electrode group connected to the conductive pad 26i. Can be connected to each other, and these can be handled as one group (for example, an A-phase electrode group).

  Similarly, one electrode group connected to the conductive pad 26b and one electrode group connected to the conductive pad 26f are defined as a B-phase electrode group, for example, and one electrode group connected to the conductive pad 26c is electrically connected to the conductive pad 26c. As one electrode group connected to the pad 26g, for example, a C-phase electrode group, one electrode group connected to the conductive pad 26d and one electrode group connected to the conductive pad 26h are, for example, a D-phase electrode group. can do.

  On the other hand, as shown in FIG. 1, a plurality of plate-like movable element side electrodes 33 are also provided on the opposing surface (movable element electrode surface) 30a on the movable element 30 side. As in the case of the stator 20, the mover side electrode 33 is formed by plating and growing a conductive metal such as copper perpendicular to the Z direction, and moves in a direction along the wide electrode surface (Y ) In a state parallel to the direction, and regularly aligned at equal intervals along the moving direction and the width direction. In the present embodiment shown in FIG. 1, the mover side electrode 33 is formed on the facing surface 30 a of the mover 30 in 7 rows and 5 columns.

  As shown in FIG. 1, the electrode interval W <b> 1 in the width direction of the stator side electrode 23 is wider than the thickness dimension t <b> 2 in the width direction of the mover side electrode 33, and similarly in the width direction of the mover side electrode 33. The electrode interval W2 is formed wider than the thickness dimension t1 of the stator side electrode 23 in the width direction. Therefore, the mover side electrode 33 is inserted between the stator side electrode 23 and the stator side electrode 23 adjacent to each other in the width direction, and the electrode surface of the stator side electrode 23 and the mover side electrode 33 are The electrode surfaces are arranged to face each other in the direction.

  Further, as shown in FIG. 2, the height dimension in the Z direction of the stator side electrode 23 and the mover side electrode 33 is such that the stator side electrode and the mover 30 are assembled in the state where the stator 20 and the mover 30 are assembled. 23 and the tip of the mover side electrode 33 are set so as not to contact the surfaces of the opposing surface 20a and the opposing surface 30a.

  In the state shown in FIG. 2, the electrode surface of the stator side electrode 23 and the electrode surface of the mover side electrode 33 are arranged to face each other in a parallel state. For this reason, when a potential difference is applied between the stator side electrode 23 and the mover side electrode 33, the respective portions where the electrode surface of the stator side electrode 23 and the electrode surface of the mover side electrode 33 face each other. Capacitors are formed.

  In the electrostatic attraction drive device shown in the present embodiment, since the plurality of stator side electrodes 23 and the mover side electrode 33 can be three-dimensionally opposed to each other, the stator side electrode 23 forming a capacitor is used. And the movable element side electrode 33 can be enlarged more than the conventional area. Therefore, as will be described later, a large electrostatic attraction force can be generated, and the mover 30 can be driven with a large driving force.

  FIG. 5 is a plan view partially showing the arrangement of the stator side electrode and the mover side electrode, and between the stator side electrodes 23 and 23 arranged in two rows in the moving direction (Y direction). A state is shown in which one row of the electrodes 33 is arranged to face each other. 6 is a timing chart showing an example of an electric signal given to the electrostatic attraction driving device shown in FIG. 5, and FIG. 7 is a plan view similar to FIG. 4 showing the operation of the electrostatic attraction driving device for each STEP. , STEP1 is a state in which a voltage is applied to the A phase electrode group and the D phase electrode group, STEP2 is a state in which a voltage is applied to the B phase electrode group and the D phase electrode group, STEP3 is a voltage to the B phase electrode group and the E phase electrode group , STEP 4 indicates a state in which a voltage is applied to the C-phase electrode group and the E-phase electrode group, and STEP 5 indicates a state in which a voltage is applied to the A-phase electrode group and the C-phase electrode group. 5 and 7, the stator electrodes 23 forming the A-phase to E-phase electrode groups are denoted by reference signs A to E, and the numbers given in the moving direction are the first row, the second row, and the like. Indicates the line number. Further, in STEP 1 to STEP 5 of FIG. 7, the stator side electrode 23 forming the electrode group to which a voltage is applied is indicated by hatching.

  As shown in FIG. 5, the arrangement in the moving direction (Y direction) is a row, the arrangement in the width direction (X direction) is a column, the first row on the Y2 side, the sixth row, the eleventh row,. , The stator electrode 23 in the (5n-4) th row is the E phase electrode group, the second row, the seventh row, the twelfth row,..., The (5n-3) th row is the A phase electrode group, The third row, the eighth row, the thirteenth row,..., The (5n-2) th row are the B-phase electrode group, the fourth row, the ninth row, the fourteenth row,. 1) A row is a C-phase electrode group, and a fifth row, a tenth row, a fifteenth row,..., A fifth n-th row is a D-phase electrode group. In addition, all the mover side electrodes 33 are electrically connected to the mover 30, but for convenience of explanation, the mover side electrode 33a, the mover side electrode 33b, the mover side electrode 33c, It is set as the child side electrode 33d.

  As shown in FIG. 5, the length dimension of the stator side electrode 23 is L1a, the distance between the adjacent stator side electrodes 23 in the moving direction is L1b, and the length dimension of the mover side electrode 33 is L2a. When the electrode interval in the moving direction of the mover side electrodes 33 adjacent to each other is L2b, the relationship between the stator side electrode 23 and the mover side electrode 33 is L1a <L2a, and is fixed at any position in the moving direction. The electrode surface of the child side electrode 23 and the electrode surface of the mover side electrode 33 are opposed to each other, and a capacitor is formed between the opposed electrodes.

  The length dimension of the stator side electrode 23 is L1a, the electrode distance in the moving direction of the stator side electrode 23 is L1b, the length dimension of the mover side electrode 33 is L2a, and the electrode distance in the moving direction is L2b. The number of phases (the number of drive phases) of the A-phase electrode group, the B-phase electrode group,... Is formed so that the following relationship is established.

  The five A-phase electrode groups, B-phase electrode groups, C-phase electrode groups, D-phase electrode groups, and E-phase electrode groups are given predetermined electrical signals as shown in FIG. That is, in STEP 1, the A phase electrode group and the D phase electrode group are applied, in STEP 2, the B phase electrode group and the D phase electrode group are applied, in STEP 3, the B phase electrode group and the E phase electrode group are applied, and in STEP 4, the C phase electrode group is applied. A phase electrode group and an E phase electrode group are applied. In STEP 5, an A phase electrode group and a C phase electrode group are applied. Each of these STEPs is repeated in the order of STEP 1 → STEP 2 → STEP 3 → STEP 4 → STEP 5 → STEP 1 → STEP 2 →.

  The electrostatic attraction driving device 10 is in an initial state as shown in STEP 1 of FIG. 7 (same as in FIG. 5), that is, the stator side electrodes in which the mover side electrodes 33a, 33c, and 33e constitute the E phase electrode group, respectively. 23 and the stator side electrode 23 constituting the A-phase electrode group are partially opposed to each other, and the mover side electrodes 33b and 33d are opposed only to the stator side electrode 23 constituting the C-phase electrode group. Suppose you are in a state of being.

  From this initial state, when a predetermined voltage is simultaneously applied to the A-phase electrode group and the D-phase electrode group as shown in STEP 1, the stator side electrode 23 that forms the A-phase electrode group located in the second row, Since the mover side electrode 33a is partially opposed, an electrostatic attraction force (Coulomb force) acts between the mover side electrode 33a and the mover side electrode 33a forms the A-phase electrode group. It is sucked into (second line). However, since the stator side electrodes 23 and 23 forming the A phase electrode group are provided at both ends in the width direction of the mover side electrode 33a, they act in the width (X) direction of the electrostatic attraction force. The components cancel each other out. On the other hand, since the component in the movement (Y) direction of the electrostatic attraction force remains, the mover side electrode 33a is moved in the Y1 direction.

  At this time, since the state where the center of the moving direction of the mover side electrode 33a coincides with the center of the moving direction of the stator side electrode 23 forming the A-phase electrode group is the most stable state, the mover side electrode 33a is It is moved to the position indicated by the dotted line in STEP 1 of FIG. This relationship is the same for the mover side electrode 33c and the A-phase electrode group in the seventh row, and the mover-side electrode 33e and the A-phase electrode group in the twelfth row. Therefore, the mover 30 is moved in the Y1 direction by a combined force of electrostatic attraction acting on the mover side electrodes 33a, 33c and 33e.

  In STEP 1, since no voltage is applied to the stator side electrode 23 that faces the mover side electrodes 33 b and 33 d and forms the C phase electrode group, the mover side electrodes 33 b and 33 d and the C phase electrode group No electrostatic attractive force (Coulomb force) acts during this period.

  Next, in STEP 2, a voltage is simultaneously applied to the B-phase electrode group and the D-phase electrode group. As shown in STEP 2 of FIG. 7, the stator side electrodes 23, 23 forming the D phase electrode group and the mover side electrodes 33 b, 33 d are partially opposed to form the B phase electrode group. No mover side electrode is in opposition to 23 and 23. Therefore, as in the case of STEP 1, the mover 30 is stable until the mover side electrodes 33 b and 33 d are positioned to the position indicated by the dotted line in STEP 2 of FIG. 7, that is, facing the stator side electrode 23 forming the D-phase electrode group. It is moved to the position to do.

  As shown in FIG. 6, in STEP 3, a voltage is applied simultaneously to the B-phase electrode group and the E-phase electrode group. In STEP 3 of FIG. 7, the stator side electrodes 23, 23 forming the B phase electrode group and the mover side electrodes 33 a, 33 c, 33 e partially face each other, and the stator side electrode 23 forming the E phase electrode group. No mover side electrodes are in opposition to each other. Therefore, similarly to the above, the mover 30 is stabilized until the mover side electrodes 33a, 33c, and 33e are positioned to the position indicated by the dotted line in STEP 3 of FIG. 7, that is, facing the stator side electrode 23 forming the B-phase electrode group. Moved to position.

  Similarly, in STEP 4 in FIG. 7, the voltage is simultaneously applied to the C-phase electrode group and the E-phase electrode group, so that the mover-side electrodes 33b and 33d of the mover 30 change from the position of the solid line to the dotted line in STEP 4 in FIG. In STEP 5 in FIG. 7, voltages are simultaneously applied to the A-phase electrode group and the C-phase electrode group, so that the mover-side electrodes 33a, 33c, and 33e of the mover 30 are the same as in STEP 5 in FIG. It is moved from the position of the solid line to the position indicated by the dotted line.

  As described above, by applying the electrical signals according to STEP 1 to STEP 5 of FIG. 6 to the electrode groups of the respective phases of the stator side electrode 23, the distance corresponding to one section of the mover side electrode arranged in the moving direction. It is possible to move in the Y1 direction by (L2a + L2b). Then, it is possible to sequentially move the mover 30 in the traveling direction (Y1 direction) by sequentially repeating a series of operations from STEP1 to STEP5.

  Further, from the same principle, if the series of operations are performed in the reverse order, for example, STEP5 → STEP4 → STEP3 → STEP2 → STEP1 → STEP5, the movable element 30 is opposite to the traveling direction (Y1 direction). It is possible to move sequentially in the direction (Y2 direction).

  In the above, as shown in FIG. 6, it is preferable that the mover 30 side be neutralized each time an H level voltage is applied in each STEP. That is, when an H level voltage is applied to the stator side electrode 23, a positive charge is generated in the stator side electrode 23, and thus a negative charge is induced in the mover side electrode 33. A capacitor is formed between the movable element side electrode 33, but the charged state in which the negative charges are accumulated is maintained in the movable element side electrode 33 only by setting the stator side electrode 23 to the L level. End up. For this reason, when the mover 30 side is not neutralized, the mover 30 becomes dull and the movement speed and the response speed are likely to be lowered.

  In order to solve this problem, the charge 30 may be discharged to the ground side (ground potential) by grounding the movable element 30 to the ground potential. However, if the mover 30 is always in a grounded state, a negative charge necessary for the mover-side electrode 33 becomes difficult to be induced, and there is a possibility that the electrostatic attraction force is reduced.

  Therefore, it is preferable that the mover 30 be neutralized at the timing when the voltage of the electric signal is switched from the H level to the L level in each STEP by using a neutralization signal as shown in FIG. As a method for removing the charge, a switching element such as a transistor can be used. Further, the charge charged in the movable element 30 may be released to the ground side (ground potential) through a resistor having a predetermined magnitude. The resistance value is determined from the relationship between the time constant RC, which is the product of the capacitance of the capacitor and the resistance value, and the time of the L level, but the charged electric charge is sufficient within the time of the L level. It is preferable to set the value so that it can be released.

  In the above description, the case where the electrostatic attraction drive device 10 is driven using a five-phase electric signal has been described. However, the present invention is not limited to this, and two or more phases such as three phases and seven phases are used. It is possible to drive using an electrical signal.

  Further, when the conductive portion 24 is formed on the facing surface 20a of the stator 20 as described above, the conductive portion 24 of the stator 20 can be opposed to the facing surface 30a on the movable element 30 side. Since the facing surface 30a is made of a conductive material, an electrostatic attraction force in the Z direction can be generated between the stator 20 and the mover 30 as well. Therefore, the mover 30 is sucked in the direction approaching the stator 20, and rattling of the mover 30 in the Z direction can be prevented. In addition, since the facing area between the stator side electrode 23 and the mover side electrode 33 can be secured above a certain level, it is possible to prevent a decrease in electrostatic attraction force in the width direction.

  Here, the electrostatic attraction force (Coulomb force) in the case of the electrostatic attraction drive device 10 will be described.

  The facing area where the electrode surface of the stator side electrode 23 and the electrode surface of the mover side electrode 33 face each other in the width direction is S, the dielectric constant between the electrodes is ε, the initial interelectrode distance is d, and the potential difference between the electrodes. Let (applied voltage) be V.

  Now, an electrostatic force f (x) works between the stator side electrode 23 and the mover side electrode 33, and the mover side electrode 33 moves in the width direction (X1 or X2 direction) by the displacement amount x. It is assumed that the stator side electrode 23 is approached.

  At this time, that is, the capacitance C between the stator-side electrode 23 and the mover-side electrode 33 after approaching is expressed by the following formula 2.

The electrostatic energy U of the capacitor at this time is given by the following formula 3.

  Therefore, the electrostatic force f (x) that works when the potential difference V moves by a displacement amount x can be expressed by the following equation (4).

  The electrostatic force f (x) expressed by the above equation 4 acts for each facing portion of the stator side electrode 23 and the mover side electrode 33, but as shown in FIGS. In the case of the present embodiment including the electrodes 33 and the six rows of stator-side electrodes 23, since there are ten opposing portions in one row, the electrostatic force F (x) for each row is the sum thereof. Therefore, when the number of facing portions is m, the electrostatic force F (x) is as shown in the following formula 5.

  Also, the same kind of electrode group is arranged at a predetermined pitch in one row. For this reason, for example, it is assumed that the electrode groups for 10 rows constituting each phase electrode group are opposed to one movable element 30 in the order of A to D. At this time, if the first row is an A-phase electrode group, the fourth and eighth rows are also an A-phase electrode group. When a voltage is applied to all the A-phase electrode groups, an electrostatic force F (x) is generated at the stator side electrodes 23 forming the A-phase electrode groups in the first, fourth, and eighth rows at the same time. Similarly, when a voltage is applied to all the B-phase electrode groups, an electrostatic force F (x) is generated in the stator side electrodes 23 that form the B-phase electrode groups in the second, fifth, and ninth rows at the same time. Therefore, if the number of rows of the same type of electrode group on the stator side that can face one movable element 30 is n, the total electrostatic force ΣF (x) generated in the electrostatic attraction driving device 10 is expressed by the following formula 6. It becomes like this.

  That is, since the mover 30 can exert a larger driving force than before, it is possible to carry more heavy objects than ever. Moreover, the electrode facing area can be increased in the height direction by orienting the electrodes of the mover and the stator vertically. Therefore, a larger driving force can be obtained by acquiring a larger electrode facing area even in a narrow space. Therefore, the electrostatic attraction drive device 10 can be reduced in size.

  Next, an electrostatic attraction drive device according to a second embodiment of the present invention will be described. FIG. 8 is a view for explaining another driving method, and is a plan view similar to FIG. 5 partially showing the arrangement of the stator side electrode and the mover side electrode.

  The electrostatic attraction driving device shown as the second embodiment has substantially the same configuration as the electrostatic attraction driving device shown in the first embodiment, but differs in the following two points.

  First, in the first embodiment, the stator side electrode 23 is connected in the width direction to the conductive portion 24 provided on the facing surface (stator facing surface) 20a to form one electrode group. However, in the second embodiment, each stator side electrode 23 is insulated and formed independently. As a result, through holes and wiring patterns connected to the individual stator side electrodes 23 are formed on the back surface (the Z2 side surface) of the stator 20 (not shown). The conductive pads of the respective wiring patterns and the connection pads on the substrate 40 side can be connected by the same means as shown in FIG. 4 and give individual electric signals to the individual stator side electrodes 23. Be able to.

  Next, the second point is that the guide grooves 21 and 21 constituting the guide means are not provided, and the guide convex portions 31 and 31 can freely move on the flat facing surface 20a in the moving direction and the width direction. It is in the point supported so that it can move. As a result, each of the stator side electrode 23 and the mover side electrode 33 functions as a guide means.

  In this embodiment, a control unit for applying a predetermined voltage to an arbitrary stator side electrode is provided.

  As shown in FIG. 8, the case where the mover side electrode 33 is at the position of the solid line on the Y2 side in the drawing is set as the initial state. From this state, the controller applies a predetermined voltage only to the stator side electrode indicated by reference numeral 23a. Thereby, the mover side electrode 33 is attracted by the electrostatic attraction force generated between the mover side electrode 33 and the stator side electrode 23a, and is moved to a position i indicated by a dotted line in FIG. That is, the mover side electrode 33 is moved to a position where the center in the movement direction of the mover side electrode 33 coincides with the center of the movement direction of the stator side electrode 23a with respect to the movement direction (Y direction). The width direction (X direction) is moved in the X1 direction in contact with the stator side electrode 23a.

  Next, the control unit applies a predetermined voltage only to the stator side electrode indicated by reference numeral 23b. As a result, the mover side electrode 33 is moved from the position i to the position ii in the same manner as described above. In this way, the control unit sequentially applies voltages to the stator side electrodes 23a, 23b, 23c, 23d,... Shown by hatching in FIG. It is possible to move along a zigzag locus indicated by → position iii → position iv, and as a result, the mover 30 can be moved in the Y1 direction. Conversely, by applying a voltage in the order of the stator side electrodes 23d, 23c, 23b, 23a, the mover 30 can be moved along the zigzag locus in the Y2 direction.

  In the second embodiment, since there is no guide means as shown in the first embodiment, the movement of the mover 30 in the X direction is allowed, that is, the movement along the zigzag locus is allowed. Can do. However, the movement range of the mover 30 in the X direction is a slight range in which the stator side electrode 23 and the mover side electrode 33 can move in the width direction, that is, the stator side electrode 23 and the mover. It is within the gap dimension between the side electrodes 33. As a result, the stator side electrode 23 and the mover side electrode 33 can substantially function as guide means for guiding the mover 30 in the moving direction.

  The electrostatic attraction driving device as described above is mounted on, for example, a mobile phone or a digital camera, and is used as a lens driving unit for autofocus that adjusts the focal length by moving the camera lens in the focus direction. FIG. 9 is a front view showing lens driving means as an application example of the electrostatic suction driving device.

  In FIG. 9, tapered portions 35, 35 are formed by obliquely cutting the edges in the width direction of the mover 30, and the lens holder 50 that holds the lens 55 is fixed to the tapered portions 35, 35. Hooks 51 and 51 are formed at both ends in the width direction of the lens holder 50, and the lens holder 50 snaps in the Z2 direction in the figure with the hooks 51 and 51 facing the mover 30. Thus, the hook portions 51 and 51 are fixed by locking the tapered portions 35 and 35. With such a configuration, the lens holder 50 can be easily attached to the mover 30.

  In this lens driving means, by giving predetermined electric signals to the stator side electrode 23 and the mover side electrode 33 as described above, the mover 30 on which the lens holder 50 is mounted is moved in a direction perpendicular to the paper surface, that is, the focus. It is possible to move in the direction.

The exploded perspective view which shows the electrostatic attraction drive device as an embodiment of the present invention, A state in which the stator and the mover face each other is shown, and a sectional view taken along line II-II in FIG. The top view which shows partially the structure of the stator as 1st Embodiment, Sectional drawing which shows one structure of the board | substrate with which a stator and a stator are attached, A plan view partially showing the arrangement of the stator side electrode and the mover side electrode, FIG. 6 is a timing chart showing an example of an electrical signal given to the electrostatic attraction drive device shown in FIG. FIG. 4 is a plan view similar to FIG. 4 showing the operation of the electrostatic suction drive device for each STEP; It is a figure for demonstrating other drive methods, The top view similar to FIG. 5 which shows partially arrangement | positioning of a stator side electrode and a needle | mover side electrode, Front view showing lens driving means as one application example of an electrostatic suction driving device, The figure which shows schematic structure of the electrostatic attraction drive device shown as patent document 1 as FIG. A timing chart of an electric signal shown in FIG.

Explanation of symbols

10 Electrostatic Suction Drive Device 20 Stator 20a Opposing Surface (Stator Opposing Surface)
21 Guide groove (guide means)
23 Stator side electrode 24 Conductive part 26 Conductive pad 30 Movable element 30a Opposing surface (moving element facing surface)
31 Guide convex part (guide means)
33 Movable element side electrode 35 Tapered part 40 Substrate 50 Lens holder 51 Hook part

Claims (5)

A stator extending along the moving direction, a mover disposed opposite to the stator, and a stator-facing surface provided on the stator and facing the mover, perpendicular to the mover direction. A stator-side electrode that protrudes and is aligned in the moving direction, and protrudes perpendicularly to the stator direction from a mover-facing surface that is provided on the mover side and faces the stator-facing surface, and also in the moving direction A mover side electrode aligned with respect to
The stator side electrode and the mover side electrode are arranged to face each other in a width direction perpendicular to the moving direction and perpendicular to the direction in which the opposing surfaces are opposed to each other, and the stator side electrode An electrostatic attraction drive device, wherein the mover is moved in the moving direction by an electrostatic attraction force generated at a portion facing the mover side electrode.   A plurality of stator side electrodes are regularly arranged at predetermined intervals along the movement direction and the width direction on the stator facing surface, and a plurality of mover side electrodes are arranged on the stator side on the mover facing surface. 2. The electrostatic attraction drive device according to claim 1, wherein the electrostatic suction drive device is regularly arranged at a position not overlapping the electrode.   A plurality of electrode groups formed by conducting and connecting a plurality of the stator side electrodes arranged in the width direction are arranged in parallel at intervals in the moving direction, and two or more phases of electrical signals are transmitted to the individual electrodes. The electrostatic attraction drive device according to claim 1, wherein the movable element is driven by being given to a group.   The electrostatic attraction drive device according to claim 1, wherein the movable element is grounded through a predetermined resistance.   The electrostatic attraction drive device according to claim 4, wherein the state of electrical connection between the mover and the ground potential is switched at a predetermined timing.

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