JP2009034779A - Driving unit, imaging unit, imaging device, and manufacturing method for driving unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of precisely setting a gap between a fixed comb-tooth electrode and a movable comb-tooth electrode. <P>SOLUTION: A driving unit 1A comprises a driving mechanism 8, which makes the movable tooth section give driving displacement to a movable section, having movable comb sections having a plate face regulated in the first and second directions and arranged in the third direction by mutually separating a plurality of first toothed plates in the first direction as a tooth-height direction, and fixed tooth sections alternately arranging a plurality of second toothed plates approximately in parallel with a plurality of first tooth sections in the first direction as a tooth height direction; and an offset mechanism 5a for making relative gaps generate between the movable comb sections and the fixed comb sections in the second direction as an offset direction. The fixed comb sections are formed to respectively integrate with the movable comb sections via elastic sections capable of elastically deforming in the offset direction, and the offset mechanism 5a makes the fixed comb sections move in the offset direction in order to generate the relative gaps by elastically deforming the elastic sections. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a driving technique using an electrostatic actuator.

  2. Description of the Related Art In recent years, small electronic devices (for example, mobile phones) to which a photographing function is added by mounting a micro camera unit (MCU) are rapidly spreading. Along with this, there is a strong demand for miniaturization of drive devices used in the AF mechanism or zoom mechanism for MCUs.

  However, in a drive device using a stepping motor or the like for the drive unit, it is necessary to secure a specific space for the drive unit, and thus it is difficult to cope with downsizing.

  Therefore, in order to realize a reduction in the size of the drive unit, a drive device has been proposed in which an electrostatic actuator of MEMS (Micro Electro Mechanical System) manufactured by making full use of a semiconductor microfabrication technique is used as the drive unit.

  The electrostatic actuator is composed of a fixed comb electrode and a moving comb electrode facing the fixed comb electrode, and in order to generate a displacement in a predetermined direction, the fixed comb electrode and the moving comb electrode are relatively displaced (position). It is arranged in a state having a deviation (also referred to as a “positional deviation state”).

  As a method of ensuring such a misalignment state, when the substrate on which the fixed comb electrode is formed and the substrate on which the movable comb electrode is bonded, the fixed comb electrode and the movable comb electrode are connected. There is known a technique of arranging them in a state of being shifted from each other (Patent Document 1).

JP 2006-79078 A

  However, in the technique described in Patent Document 1, in order to accurately set the deviation between the fixed comb electrode and the movable comb electrode, the fixed comb electrode and the movable comb electrode are accurately set at the time of bonding. There is a problem of having to position well.

  Then, an object of this invention is to provide the technique which can set the shift | offset | difference between a fixed comb electrode and a moving comb electrode accurately.

  In order to solve the above-mentioned problems, the invention of claim 1 is a drive device for driving a movable part, and has a plate surface defined by a first direction and a second direction, and the first direction has a tooth height. A plurality of first tooth plates having a plurality of first tooth plates arranged in a third direction and spaced apart from each other, and a plurality of second tooth plates having a first tooth direction as the first direction. A fixed comb electrode arranged alternately in parallel with one tooth plate, a drive mechanism for driving displacement of the movable comb electrode to the movable portion, the movable comb electrode and the fixed comb Offset means for generating a relative displacement between the field electrode and the second direction as an offset direction, and the fixed comb electrode is moved through an elastic portion elastically deformable in the offset direction. It is formed integrally with a comb electrode, and the offset means is The serial elastic portion is elastically deformed to move the fixed comb electrodes on the offset direction, and wherein the generating the relative displacement.

  According to a second aspect of the present invention, in the drive device according to the first aspect of the present invention, the offset means includes a base having a stepped portion, and the stepped portion includes the base and the drive in the base. When the mechanism is joined, the elastic portion is elastically deformed and the fixed comb electrode is present in a position to move in the offset direction, and the stepped portion is attached to the fixed comb electrode along with the joining. And the relative displacement between the movable comb electrodes.

  The invention according to claim 3 is the drive device according to claim 1 or 2, wherein the movable comb electrode and the fixed comb electrode are one of two Si layers in the SOI substrate. It is characterized by being produced by etching from one direction using a Si layer.

  According to a fourth aspect of the present invention, in the drive device according to the second or third aspect of the present invention, the stepped portion is a convex portion provided on the base.

  According to a fifth aspect of the present invention, in the driving device according to the second or third aspect of the present invention, the step portion is a concave portion provided in the base.

  According to a sixth aspect of the present invention, in the drive device according to any of the first to fifth aspects of the present invention, the step of the stepped portion is not longer than the length of the side parallel to the offset direction on the comb tooth surface. It is characterized by that.

  According to a seventh aspect of the present invention, in the drive device according to any one of the first to sixth aspects of the present invention, an imaging element is disposed in the movable portion.

  The invention according to claim 8 is characterized in that the drive device according to the invention of claim 7 is arranged in an internal space of a single housing.

  A ninth aspect of the present invention is an imaging apparatus, comprising the imaging unit according to the eighth aspect of the invention.

  According to a tenth aspect of the present invention, there is provided a method of manufacturing a driving device for driving a movable part, and a) a plate surface defined by a first direction and a second direction, and the first direction as a tooth height direction. A plurality of first tooth plates are arranged in a third direction at intervals, and a plurality of second tooth plates having the first direction as a tooth height direction are the plurality of first tooth plates. A step of integrally forming a drive mechanism having fixed comb electrodes arranged alternately and substantially parallel to the tooth plate, and the movable comb electrodes provide drive displacement to the movable portion; b) In the step of generating a relative shift between the moving comb electrode and the fixed comb electrode with the second direction as an offset direction, and in the step a), the fixed comb electrode is in the offset direction. Formed integrally with the moving comb electrode through an elastically deformable elastic part Is, in the above b) step, the fixed comb electrodes, the elastic portion is elastically deformed to move in the offset direction, and wherein the generating the relative displacement.

  The invention of claim 11 is a drive device for driving a movable part, comprising: a movable comb electrode that applies drive displacement to the movable part; and fixed comb electrodes that are alternately arranged on the movable comb electrode. A relative shift in the offset direction perpendicular to the extending direction of the comb teeth is generated in the comb tooth surface of the movable comb electrode between the driving comb electrode and the fixed comb electrode and the movable comb electrode. And the fixed comb electrode is formed integrally with the movable comb electrode via an elastic portion elastically deformable in the offset direction, and the offset means elastically deforms the elastic portion. The fixed comb electrode is moved in the offset direction to generate the relative shift.

  According to the first to eleventh aspects of the present invention, the movable comb electrode and the fixed comb electrode are integrally formed, and the fixed comb electrode is moved in the offset direction. It is possible to accurately set the deviation from the comb electrode.

  In particular, according to the invention described in claim 3, the movable comb electrode and the fixed comb electrode are produced by etching from one direction using one Si layer of the two Si layers in the SOI substrate. Therefore, the manufacturing time of the moving comb electrode and the fixed comb electrode can be shortened.

  In particular, according to the invention described in claim 6, since the step of the step portion is equal to or shorter than the length of the side parallel to the offset direction on the comb tooth surface, it is between the fixed comb electrode and the movable comb electrode. In the state where the relative displacement in the offset direction occurs, it is possible to secure a portion where each comb tooth surface of the moving comb electrode and each comb tooth surface of the fixed comb electrode overlap each other. An initial pulling force can be generated between the comb electrodes.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment>
<About electrostatic actuator>
FIG. 1 is a diagram showing a first situation of the configuration and operation of an actuator (electrostatic actuator) using electrostatic action. FIG. 1A is a top view of the electrostatic actuator, and FIG. 1B is a side view of the electrostatic actuator.

  FIG. 2 is a diagram showing a second situation of the configuration and operation of the electrostatic actuator. FIG. 2A is a top view of the electrostatic actuator. FIG. 2B is a side view of the electrostatic actuator, and FIG. 2C is a side view of the electrostatic actuator when a voltage is applied.

  In the present embodiment, an electrostatic actuator is employed in the drive unit of the drive device. As shown in FIG. 1 (a), the electrostatic actuator has a comb-shaped portion arranged alternately (alternately arranged). It is composed of one comb-tooth electrode 101 and a second comb-tooth electrode 102, and an electrostatic force generated by a voltage applied between the two comb-tooth electrodes is used as a drive source. Such an electrostatic actuator generates forces in different directions depending on the relative positions of the two comb electrodes. In the figure, an XYZ rectangular coordinate system is written, but the X-axis direction corresponds to the direction in which each tooth of the first comb electrode 101 extends (also referred to as “comb extending direction”), and the Y-axis The direction corresponds to the direction along the interdental groove of the two comb electrodes 101 and 102 (also referred to as “comb thickness direction” or “direction perpendicular to the comb extension direction in the comb surface”). The Z-axis direction corresponds to the direction in which the teeth of the two comb electrodes are alternately arranged (also referred to as “alternate arrangement direction” or “gap direction”). Further, when expressing that the comb teeth of the two comb-tooth electrodes are alternately arranged in the horizontal direction, the Y-axis direction is also expressed as the vertical direction.

  For example, as shown in FIG. 1B, a fixed first comb electrode (also referred to as “fixed comb portion”) 101 and a movable second comb electrode (also referred to as “movable comb portion”) 102. The movement of the moving comb portion 102 in a state where the comb tooth surfaces are arranged without deviation in the Y-axis direction will be described.

  In this state, when the contact of the switch SW is configured and a voltage is applied between the two comb electrodes, an attractive force in the X direction is generated between the fixed comb portion 101 and the moving comb portion 102. The moving comb portion 102 connected to the fixed portion 104 moves in the + X direction by this attractive force via the support member 103a formed of an elastic material extending in the X direction. When the switch SW is disconnected, the attractive force generated between the fixed comb portion 101 and the moving comb portion 102 disappears, and the moving comb portion 102 returns to the −X direction by the elastic force of the support member 103a.

  Thus, in a state where the mutual comb tooth surfaces are arranged without shifting in the Y-axis direction, the movable comb portion 102 is moved in the X direction as indicated by the arrow HYa by controlling the voltage applied between the comb electrodes. Can be moved to.

  Next, the comb tooth surface is not arranged in the Y-axis direction without being shifted as shown in FIG. 1B, and the comb tooth surface of the moving comb portion 102 is the comb of the fixed comb portion 101 as shown in FIG. The movement of the moving comb portion 102 in a state shifted in the Y-axis direction with respect to the tooth surface (also referred to as “position shift state” or “offset state”) will be described. However, unlike the support member 103a in FIG. 1, the support member 103b in FIG. 2 is linear in a top view.

  In this state, when the contact of the switch SW is configured and a voltage is applied between the two comb electrodes, an attractive force in the X direction and an attractive force in the Y direction are generated between the fixed comb portion 101 and the moving comb portion 102. As a result, the moving comb portion 102 connected to the fixed portion 104 via the rod-like support member 103b receives the force Fx in the + X direction and the force Fy in the −Y direction. The support member 103b is formed of a shape or material that has bending elasticity but does not have substantial elastic elasticity. Therefore, the moving comb portion 102 does not move in the −X direction, but moves in the substantially −Y direction while bending the support member 103b by receiving the force Fy in the −Y direction (see FIG. 2C). ). When the contact of the switch SW is opened, the attractive force generated between the fixed comb portion 101 and the moving comb portion 102 disappears, and the moving comb portion 102 returns to the approximately + Y direction by the bending elastic force of the support member 103b. To do.

  Thus, the comb tooth surface of the moving comb portion 102 is displaced in the Y-axis direction with respect to the fixed comb portion 101, in other words, in the direction perpendicular to the extension direction of the comb teeth (also referred to as “offset direction”) within the comb tooth surface of the comb portion. In such a state, the movable comb portion 102 can be rotationally moved (turned) as indicated by an arrow HYb by controlling the voltage applied between the comb electrodes.

  The moving comb portion 102 has a comb tooth surface (plate surface) defined by the first direction and the second direction, and a plurality of first tooth plates having the first direction as the tooth height direction are spaced apart from each other. It is expressed as a moving comb portion 102 arranged in three directions, and a plurality of second tooth plates in which the fixed comb portion 101 has the first direction as the tooth height direction are alternately arranged substantially parallel to the plurality of first tooth plates. The second direction is the offset direction.

  Further, the force generated between the comb electrodes by the applied voltage increases in proportion to the number of comb teeth, and increases in proportion to the square of the applied voltage. On the other hand, the force generated between the comb-teeth electrodes is inversely proportional to the distance between the comb teeth, and decreases as the distance between the comb teeth increases. In addition, each comb tooth is preferably arranged at a neutral position so that the distance between each comb tooth electrode is equal to prevent short circuit due to contact. Devices such as giving rigidity are applied.

<About the drive unit>
<Configuration>
Next, the drive device 1A according to the present embodiment will be described. FIG. 3 is a functional block diagram of the driving apparatus 1A according to the present embodiment. FIG. 4 is a top view of the driving apparatus 1A. FIG. 5 is a side view of the driving device 1A in an initial state before driving when viewed from the K1 direction in FIG. In FIG. 5, for the sake of clarity, the illustration of the fixed portion FX1 and the elastic portions 16a and 16c is omitted, and the fixed comb portions 101a and 101c are represented by broken lines.

  As shown in FIG. 3, the drive device 1 </ b> A has a drive mechanism 8 that includes a drive unit 5, a displacement transmission unit 6, and a movable unit 7.

  The drive unit 5 has a function of generating a displacement (also referred to as “drive displacement”) and applying the drive displacement to the displacement transmission unit 6. In the present embodiment, the above-described electrostatic actuator is employed in the drive unit 5 and a drive displacement is generated by applying a voltage between the comb electrodes. Specifically, the drive unit 5 includes an offset mechanism 5a, and the comb tooth surface of the moving comb portion of the electrostatic actuator and the comb tooth surface of the fixed comb portion are arranged in a state of being offset from each other in the offset direction. The drive unit 5 generates a drive displacement in the offset direction according to the applied voltage (details will be described later).

  The displacement transmitting unit 6 includes a displacement enlarging mechanism 6 a, and has a function of generating an output displacement obtained by enlarging (enlarging) the driving displacement given from the driving unit 5 and transmitting the output displacement to the movable unit 7. Yes.

  The movable part 7 is moved in a predetermined direction according to the output displacement.

  Here, a specific configuration of the driving device 1A including the above functional units will be described.

  As shown in FIG. 4, the driving apparatus 1 </ b> A has a substantially rectangular frame structure FR that is spaced from the movable portion 7 along the outer periphery of the movable portion 7 that fixes the driven body. The frame structure FR is divided in half. The first frame 11 corresponding to one of them (the upper half in the figure) and the second frame corresponding to the other one (the lower half in the figure). The frame 21 is disposed symmetrically with respect to the symmetry line CC of the movable portion 7. The drive device 1A also includes four electrostatic actuators 10a, 10b, 10c, and 10d as the drive unit 5 for driving the movable unit 7 via the frame structure FR. Each of the electrostatic actuators 10a to 10d includes fixed comb portions 101a, 101b, 101c, and 101d, and movable comb portions 102a, 102b, 102c, and 102d that face the fixed comb portions 101a to 101d, respectively, and between the comb electrodes. A drive displacement is generated in accordance with the voltage applied to.

  Although the frame structure FR is an element of the displacement transmission unit 6 in FIG. 3, the structure and function of the first frame 11 will be described in detail below. The second frame 21 also has the same structure and function as the first frame 11.

  The first frame 11 is formed by a horizontal side portion 11L and a pair of vertical side portions 11H which are continuous on both sides of the horizontal side portion 11L, and one end thereof is fixed to the fixing portions FX1 and FX2, respectively. The support member 13a and the second support member 13b support a portion closer to the symmetric line CC than the midpoint of each of the pair of vertical sides 11H. The first support member 13a and the second support member 13b are formed of a material having torsional elasticity (for example, Si). More specifically, these support members 13a and 13b may be integrally formed with the first frame 11, but by being designed to be thinner (or thinner) than the first frame 11, It is formed as an elastic member that is more elastically torsionally deformed than the first frame 11.

  Further, moving comb portions 102a and 102b, which are elements of the electrostatic actuators 10a and 10b, are connected to both ends of the first frame 11, and drive displacements from the electrostatic actuators 10a and 10b are applied to the first frame 11, respectively. Given. Specifically, in each of the electrostatic actuators 10a and 10b, the fixed comb portions 101a and 101b are displaced in the thickness direction (offset direction) of the comb teeth of the moving comb portions 102a and 102b with respect to the moving comb portions 102a and 102b. It is arranged in a state having Accordingly, the electrostatic actuators 10a and 10b can move the moving comb portions 102b and 102a respectively connected to the connection ends PFa and PFb of the vertical side portion 11H in the Y direction (offset direction) based on the same principle as in FIG. Can be driven.

  The fixed comb portions 101a and 101b arranged in a state of being displaced with respect to the moving comb portions 102a and 102b are connected to the fixed portions FX1 and FX2 via the elastic portions 16a and 16b, respectively.

  A fixed portion FX1 to which one end of the first support member 13a and one end of the elastic portion 16a are connected, and a fixed portion FX2 to which one end of the second support member 13b and one end of the elastic portion 16b are connected are described later. The drive mechanism 8 including the electrostatic actuators 10a and 10b and the first frame 11 is held by being joined to the base FD1.

  The elastic portions 16a and 16b have bending elasticity in the Y-axis direction and are fixed to the base FD1 in a bent state (see FIG. 16). Details will be described later.

  In the first frame 11, the first long portion 12 a extending from the connection end PFa of the electrostatic actuator 10 a through the support point (also referred to as “coupling portion”) BPa by the first support member 13 a is the first This corresponds to one of the vertical sides 11H of one frame 11, and is an element of the displacement enlarging mechanism 6a (FIG. 3) of the first frame 11. Specifically, as shown in FIG. 5, the first long portion 12a is configured to be tiltable in the XY plane with the support point BPa as a fulcrum, and the support point BPa is the first long length. It is provided between the midpoint of the part 12a and one end PFa of the first long part 12a. For this reason, the first elongate portion 12a uses a so-called lever principle to change the drive displacement applied to one end (connection end PFa) of the first elongate portion 12a in addition to the first elongate portion 12a. It becomes possible to enlarge and output at the end PEa.

  Further, in the first frame 11, the second elongated portion 12b extending from the connection end PFb of the electrostatic actuator 10b through the support point (coupling part) BPb by the second support member 13b is also the first frame 11. It corresponds to another one of the vertical side portions 11H of the frame 11 and is an element of the displacement enlarging mechanism 6a (FIG. 3) of the first frame 11 as with the first frame 11.

  Further, the approximate center of the lateral side portion 11 </ b> L of the first frame 11 is connected to the movable portion 7 by the first connecting member 14. The first connecting member 14 is formed of a material having bending elasticity (for example, Si). Specifically, a part of the members integrally formed with the first frame 11 is compared with the first frame 11. The first connecting member 14 can be obtained by designing it to be thin (or thin), and even if it is made of the same material as the first frame 11, the first size can be selected by such relative size selection. Compared with the frame 11, it is easily elastically deformed.

  The second frame 21 has the same configuration as the first frame 11 described above, and is an element of the displacement transmission unit 6. In brief, the second frame 21 is supported by a third support member 13c and a fourth support member 13d. Further, moving comb portions 102c and 102d are connected to both ends of the second frame 21, respectively. And each fixed comb part 101c, 101d arrange | positioned in the position facing the moving comb parts 102c, 102d is respectively connected to fixed part FX1, FX2 via the elastic parts 16c, 16d. The second frame 21 includes a third elongated portion 12c and a fourth elongated portion 12d, each having a support point (bonding site) BPc and a support point (bonding site) BPd as fulcrums. These long portions 12c and 12d are elements of a displacement enlarging mechanism 6a that can tilt in the XY plane.

  Further, the second frame 21 has a second connecting member 15. The second connecting member 15 is designed to be thinner (or thinner) than the second frame 21 and is more easily elastically deformed than other parts of the second frame 21. And the said 1st connection member 14 and the said 2nd connection member 15 are comprised so that the movable part 7 may be hold | maintained in the position (symmetric position) which mutually opposes.

  As described above, the upper half and the lower half with the symmetry line C-C of the movable portion 7 as a boundary have a symmetric configuration, and each is a unit drive mechanism. In this embodiment, the two unit drive mechanisms are symmetrically arranged with respect to the movable part 7, but the function itself for moving the movable part 7 has each one unit drive mechanism.

<Operation>
Next, the operation of the driving apparatus 1A having the above-described configuration will be described. FIG. 6 is a side view of the driving device 1A in a driving state when viewed from the K1 direction in FIG. FIG. 7 is a diagram illustrating an initial state and a driving state of the driving apparatus 1A. In FIG. 7, illustration of the fixed comb portions 101 a and 101 c is omitted for the sake of clarity.

  In the initial state before driving shown in FIG. 5, when the force Fay in the −Y direction is applied from the electrostatic actuator 10 a to the one end PFa side of the first long portion 12 a, the first long portion 12 a is elastic. While the deformable first support member 13a is twisted, it rotates (rotates) in the XY plane around the support point BPa against the elastic force of the support member 13a. In short, one end PFa of the first elongate portion 12a is displaced in the −Y direction, and the other end PEa of the first elongate portion 12a is displaced in the + Y direction.

  Similarly, when a force Fcy in the −Y direction is applied from the electrostatic actuator 10c to the one end PFc side of the third long portion 12c, the third long portion 12c becomes a third support member that can be elastically deformed. It rotates about the support point BPc while generating a twist in 13c. In short, one end PFc of the third long portion 12c is displaced in the −Y direction, and the other end PEc of the third long portion 12c is displaced in the + Y direction.

  In addition, the second long portion 12b and the third long portion 12d (not shown in FIG. 5) are also tilted by receiving the force from the electrostatic actuators 10b and 10d, respectively, and the long portions 12b and 12d The other ends PEb and PEd are displaced in the + Y direction.

  And the output displacement which arose in each other end PEa of the two elongate parts 12a and 12b in the 1st flame | frame 11 is transmitted to the movable part 7 via the 1st connection member 14, and 2nd The output displacement generated on the other end PEc, PEd side of the two long portions 12c, 12d in the frame 21 is transmitted to the movable portion 7 via the second connecting member 15. As the output displacement increases, the movable portion 7 moves in the + Y direction as shown in FIG.

  At this time, the first connecting member 14 and the second connecting member 15 hold the movable portion 7 while being elastically deformed as the movable portion 7 moves in the + Y direction. As a result, the smooth operation of the driving device 1A becomes possible.

  Specifically, as described above, each of the long portions 12a to 12d performs rotational movement around the support points BPa to BPd during driving. For this reason, the output displacement generated at the other ends PEa to PEd of the long portions 12a to 12d includes the displacement QX in the X direction and the displacement QY in the Y direction.

  For example, in the driving state shown in FIG. 7, the output displacement (first output displacement) generated by the first long portion 12a and the second long portion 12b is represented by an arrow AR1. The first output displacement can be represented by a displacement QX1 in the −X direction and a displacement QY1 in the + Y direction. Further, in the driving state shown in FIG. 7, the output displacement (second output displacement) generated by the third long portion 12c and the fourth long portion 12d is represented by an arrow AR2. The second output displacement can be represented by a displacement XX2 in the + X direction and a displacement QY2 in the -Y direction.

  As described above, the first output displacement in the first frame 11 and the second output displacement in the second frame 21 have the displacement QX1 in the −X direction and the displacement QX2 in the + X direction, respectively. . Therefore, in the driving state of FIG. 7, the distance between the other end PEa of the first long portion 12a and the other end PEc of the third long portion 12c is compared with the distance in the initial state of FIG. And shortened. Therefore, in the driving apparatus 1A using the displacement magnifying mechanism 6a as described above, the first connecting member 14 and the second connecting member 15 are designed to be more easily elastically deformed than the frame, and 2 during operation. By elastically deforming the two connecting members (in this case, bending deformation is generated), the displacement in the X direction caused by driving is absorbed, and the operation of the two unit driving mechanisms in the driving device 1A in parallel is facilitated. ing.

  Further, as described above, in the driving device 1A, the first connecting member 14 and the second connecting member 15 sandwich the movable portion 7 at a position facing each other. According to this, the −X direction force F14 applied from the first connecting member 14 to the movable portion 7 and the + X direction force F15 applied from the second connecting member 15 to the movable portion 7 are mutually on the same straight line. It becomes possible to add to the movable part 7 from the facing direction. Therefore, the posture of the movable portion 7 is maintained without disturbing the balance of the movable portion 7 by the force F14 from the first connecting member 14 and the force F15 from the second connecting member 15 in operation. The movable part 7 can be moved in the Y direction parallel to the X axis (while maintaining).

  As described above, the movable portion 7 that moves in the + Y direction as the output displacement increases is the force from the electrostatic actuators 10a, 10b, 10c, and 10d and the long portions 12a, 12b, 12c, and 12d. The support members 13a, 13b, 13c, and 13d generated by the tilting are stopped at a position where the restoring force of the twist is balanced. For example, when the application of the voltage between the comb electrodes is stopped, the movable portion 7 returns to the original position by the restoring force of each of the support members 13a to 13d that has been twisted. Thus, since the displacement of the movable part 7 is determined by the force generated in the electrostatic actuators 10a to 10d and the restoring force of the torsion, the displacement of the movable part 7 in the driving device 1A is applied between the comb electrodes. Is adjusted by controlling the magnitude of the applied voltage.

<Production method>
Next, a method for manufacturing the driving device 1A will be described. FIG. 8 is a flowchart showing a manufacturing process of the driving device 1A. FIG. 9 is a view showing an SOI (Silicon On Insulator) substrate 50. FIG. 10 is a diagram showing a mask patterned on the surface of the formation layer SL1, and FIG. 11 is a diagram showing a mask patterned on the surface of the auxiliary layer SL2. 12, FIG. 13, FIG. 14 and FIG. 16 are explanatory diagrams of each manufacturing process of the driving device 1A. FIG. 15 is a diagram illustrating the position of the convex portion TB on the base FD1.

  As shown in FIG. 8, in steps SP1 to SP3, the driving mechanisms 8 such as the frames 11 and 21 and the driving unit 5 are integrally formed from the SOI substrate 50, and in step SP4, the manufactured driving mechanism 8 is based on the base. It is joined to the base FD1.

Specifically, in step SP <b> 1, the outer shapes of the drive mechanisms 8 such as the frames 11 and 21 and the drive unit 5 are formed on the SOI substrate 50. Here, the SOI substrate 50 (see FIG. 9) includes a relatively thick (eg, 200 μm) Si layer (also referred to as “formation layer”) SL1 and a relatively thin (eg, 5 μm) Si layer (“auxiliary layer”). SL2 and a relatively thin (eg, 5 μm) SiO ₂ layer (also referred to as “sacrificial layer”) GS sandwiched between the two Si layers SL1 and SL2.

  In step SP1, a mask corresponding to the upper surface outline of the driving apparatus 1A shown in FIG. 4 is patterned on the surface of the formation layer SL1 of the SOI substrate 50, and a mask corresponding to the lower surface outline of the driving apparatus 1A is formed on the SOI substrate 50. Patterned on the surface of the auxiliary layer SL2. In the patterning performed on the surface of the formation layer SL1, portions corresponding to the connecting members 14 and 15, the supporting members 13a to 13d, and the elastic portions 16a to 16d in the outer shape of the upper surface of the driving device 1A (in FIG. 10). The mask of the portion (shown by a broken line) is removed. In the patterning performed on the surface of the auxiliary layer SL2, the mask corresponding to the moving comb portions 102a to 102d (the portion indicated by the broken line in FIG. 11) in the outer shape of the lower surface of the driving device 1A is removed.

  Then, unnecessary thin films (Si layers) in the formation layer SL1 and the auxiliary layer SL2 are removed to the surface of the sacrificial layer GS by dry etching (see FIG. 12). By this step SP1, the comb-shaped drive unit 5 and the like are formed in the formation layer SL1 of the SOI substrate 50 shown in FIG.

In step SP2, the sacrificial layer GS is removed. The sacrificial layer GS is removed by wet etching using HF (hydrofluoric acid) that dissolves SiO ₂ . Specifically, the sacrificial layer GS exposed by the etching in step SP1 is removed by wet etching. For example, the removal of the sacrificial layer GS does not remove the unexposed sacrificial layer GS in the fixed comb portions 101a to 101d, the frames 11 and 21, the fixed portions FX1 and FX2, and the exposed sacrificial layers in the moving comb portions 102a to 102d. GS is removed (see FIG. 13).

  The drive mechanism 8 is formed through the steps SP1 and SP2 as described above. Specifically, in the drive mechanism 8, the moving comb portions 102 a to 102 d (in FIG. 13, the moving comb portions 102 a and 102 c) are formed of one layer of the formation layer SL 1, and are fixed portions FX 1 and FX 2, fixed comb portions 101 a to 101 d, The frames 11 and 21 and the movable part 7 are formed of three layers of a formation layer SL1, a sacrificial layer GS, and an auxiliary layer SL2. Further, in the drive mechanism 8, the connecting members 14, 15, the support members 13a to 13d and the elastic portions 16a to 16d are formed by one layer of the relatively thin auxiliary layer SL2, and are bent or deformed compared to other portions. It is formed as an elastic member that is easily torsionally deformed.

  In the next step SP3 (FIG. 8), electrical wiring to the electrostatic actuators 10a to 10d used in the drive unit 5 is performed by wire bonding or the like.

  In step SP4, the drive mechanism 8 and the base FD1 are joined.

  As shown in FIG. 14, the base FD1 used for joining has a step portion (here, a convex portion TB) on the joining surface MF. The stepped portion (convex portion TB) is present at a position on the base FD1 where the fixed comb portions 101a to 101d are moved in the + Y direction when the fixing portions FX1 and FX2 of the driving mechanism 8 and the base FD1 are joined. To do. For example, as shown in FIG. 15, the convex portion TB is present at a position in contact with the fixed comb portions 101 a to 101 d on the base FD <b> 1 (portion surrounded by a broken line).

  When the base FD1 having such a convex portion TB and the drive mechanism 8 are joined (step SP4), the fixed comb portions 101a to 101d are pushed up in the + Y direction by the convex portions TB, and the bending elasticity in the Y-axis direction. Each elastic part 16a-16d which has is will be in the bent state (refer FIG. 16). When the elastic portions 16a to 16d are fixed in a bent state, that is, when the fixed comb portions 101a to 101d are moved in the + Y direction, the fixed comb portions 101a to 101d are in the Y direction (offset) with respect to the moving comb portions 102a to 102d. (Direction) relative displacement (also simply referred to as “displacement”).

  The step of the step portion (here, the height of the convex portion TB) (also referred to as “offset amount”) is the thickness of the comb tooth (specifically, the length of the side parallel to the offset direction on the comb tooth surface). It is preferable that According to this, in the offset state, it is possible to secure a portion where each comb tooth surface of the moving comb portions 102a to 102d and each comb tooth surface of the fixed comb portions 101a to 101d overlap each other. An initial pulling force can be generated between the electrodes.

  Further, by adjusting the size of the step, or adjusting the position at which the step portion contacts the fixed comb portions 101a to 101d or the elastic portions 16a to 16b when the drive mechanism 8 and the base FD1 are joined. Accordingly, it is possible to accurately set the shift amount between the comb tooth surfaces of the moving comb portions 102a to 102d and the comb tooth surfaces of the fixed comb portions 101a to 101d.

  Thus, in joining the drive mechanism 8 and the base FD1, an offset is generated that causes the fixed comb portions 101a to 101d to move to cause a positional shift between the fixed comb portions 101a to 101d and the movable comb portions 102a to 102d.

  As described above, in the manufacturing process of the drive device 1A, the drive mechanism 8 is formed by etching or the like in steps SP1 to SP3. Since the fixed comb portions 101a to 101d and the corresponding moving comb portions 102a to 102d are formed using the formation layer SL1 of the SOI substrate 5, the drive mechanism formed through the steps SP1 to SP3 (“drive after integral formation”). The fixed comb portions 101a to 101d and the movable comb portions 102a to 102d in FIG. 8 are formed in the same plane where the formation layer SL1 is present. Therefore, in the drive mechanism 8 after the integral formation, the comb tooth surfaces of the fixed comb portions 101a to 101d and the comb tooth surfaces of the movable comb portions 102a to 102d are arranged without deviation in the Y-axis direction.

  In step SP4, the base FD1 having the convex portion TB and the drive mechanism 8 are joined, so that the relative displacement in the Y-axis direction is fixed between the fixed comb portions 101a to 101d and the movable comb portions 102a to 102d. To generate a position shift state (offset state). As a result, each of the electrostatic actuators 10a, 10b, 10c, and 10d can generate a drive displacement in the Y direction in response to application of a voltage.

  The base FD1 moves the fixed comb electrode by joining with the drive mechanism 8, and between the fixed comb electrode and the movable comb electrode in the extending direction of each comb tooth in the movable comb electrode. It is also expressed as functioning as offset means for generating a deviation in the vertical offset direction.

  In addition, the elastic portions 16a to 16d are formed so that the length of the side in the Z-axis direction is longer than the length of the side in the Y-axis direction on the cut surface of the plane perpendicular to the X-axis. ˜16d is an elastic member that is easily bent and deformed in the Y-axis direction and hardly elastically deformed in the Z-axis direction. According to this, the elastic portions 16a to 16d function as a guide member that guides the fixed comb portions 101a to 101d in one direction (here, the offset direction), and between the gaps of the movable comb portions 102a to 102d and the fixed comb portions 101a to 101d. It is possible to perform offset while keeping the distance.

  As described above, the driving device 1A according to the present embodiment has a plate surface defined by the first direction and the second direction, and a plurality of first tooth plates having the first direction as the tooth height direction are spaced apart from each other. The movable comb portions 102a to 102d arranged in the third direction across the plurality of second tooth plates with the first direction as the tooth height direction are alternately arranged substantially parallel to the plurality of first tooth plates. The fixed comb portions 101a to 101d are arranged in the second direction between the drive comb 8 where the movable comb portions 102a to 102d give drive displacement to the movable portion 7, and the fixed comb portions 101a to 101d and the movable comb portions 102a to 102d. And an offset mechanism 5a that generates a relative displacement as an offset direction. The fixed comb portions 101a to 101d are integrally formed with the moving comb portions 102a to 102d via elastic portions 16a to 16d that can be elastically deformed in the offset direction, respectively, and the offset mechanism 5a elastically deforms the elastic portions 16a to 16d. Then, the fixed comb portions 101a to 101d are moved in the offset direction to generate a relative shift. According to this, since the movable comb portions 102a to 102d and the corresponding fixed comb portions 101a to 101d are integrally formed and the fixed comb portions 101a to 101d are moved in the offset direction, the fixed comb portions 101a to 101d and the movable comb portions 102a to 102a It is possible to accurately set a deviation from the distance 102d.

Further, as a method of ensuring the misalignment state, a fixed comb electrode and a movable comb electrode are obtained by etching each SOI substrate having a Si layer of a comb tooth thickness above and below via the SiO ₂ layer from above and below. Can be considered, and a method of manufacturing an electrostatic actuator in a state of being displaced is conceivable. However, in this method, the fixed comb electrode and the moving comb electrode are produced in separate steps from the top and bottom directions, so that it is difficult to produce the comb teeth with high accuracy. Takes a lot of time. On the other hand, in the driving apparatus 1A, the fixed comb electrode and the movable comb electrode can be formed in the same process by etching from one direction, so that the comb can be accurately manufactured. At the same time, it is possible to reduce the manufacturing time of the comb teeth.

<Application example>
Next, an application example of the driving apparatus 1A of the above embodiment will be described.

  As such an application example, there is an imaging unit that employs the driving device 1A as an AF mechanism, and there is an imaging device provided with the imaging unit. FIG. 17 is a diagram illustrating the imaging unit 30. FIG. 18 is a diagram illustrating an imaging device 70 including the imaging unit 30.

  As shown in FIG. 17, the imaging unit 30 includes a package (box body: housing) 35 and a protective glass 36, and the drive device 1 </ b> A is contained in a sealed space formed by the package 35 and the protective glass 36. And an image sensor 31 and the like disposed on the movable portion 7.

  The image pickup device (for example, CCD) 31 is configured as an area sensor in which primary color transmission filters of R (red), G (green), and B (blue) are arranged in a checkered pattern (Bayer array) in pixel units. It functions as an imaging means for acquiring such an image signal (image). Further, the image pickup device 31 is disposed (installed) on the movable portion 7 of the drive device 1A installed on the lead frame 37 in the sealed space.

  In the imaging unit 30 having such a configuration, the imaging element 31 can be moved as indicated by a double-headed arrow HW by controlling the voltage applied between the comb electrodes.

  In order to prevent dust from entering the space formed by the package 35 and the protective glass 36, the imaging unit 30 is assembled in a clean room (or clean bench), for example. Further, the imaging unit 30 forms a sealed space to prevent dust from entering the electrostatic actuators 10a, 10b, 10c, and 10d used in the driving unit 5 of the driving device 1A. 10c and 10d are protected. Moreover, in the imaging unit 30, since the air convection is eliminated by forming the sealed space, variation in the load on the driving device 1A can be reduced.

  Further, the imaging unit 30 is mounted on, for example, the imaging device 70 shown in FIG. The imaging device 70 includes an imaging unit 30 and a photographing optical system 71 such as a zoom lens. The imaging unit 30 is disposed at a position where a subject image guided from the photographing optical system 71 can be acquired.

  In the imaging device 70 having such a configuration, the focus adjustment is performed by moving the imaging device 31 in the direction of the optical axis L by controlling the voltage applied between the comb electrodes of the driving device 1A.

  As described above, the drive device 1A that can be miniaturized is employed as a drive device that drives components in the imaging unit, for example, and enables further miniaturization of the imaging unit.

<Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the contents described above.

  For example, in the above-described embodiment, the base FD1 having the convex portion TB as the stepped portion is joined to the driving mechanism 8 so that the comb tooth surfaces of the fixed comb portions 101a to 101d and the comb tooth surfaces of the movable comb portions 102a to 102d are connected. In the meantime, a relative positional shift has occurred, but the present invention is not limited to this. 19 and 20 are explanatory diagrams of a manufacturing process of the driving device 1B according to the modification.

  Specifically, as shown in FIG. 19, using a base FD2 having a recess UB as a stepped portion, a relative positional shift is caused between the fixed comb portions 101a to 101d and the movable comb portions 102a to 102d. May be.

  The concave portion UB is provided at a position facing the position where the fixed comb portions 101a to 101d exist in the base FD2 when the drive mechanism 8 and the base FD2 are joined.

  When offset is performed using the base FD2 having such a recess UB, the fixing comb portions 101a to 101d are joined using a jig (not shown) for joining the fixing portion FX1 and the base FD2 and assisting the processing. To fix the fixing comb portions 101a to 101d to the base FD2. As shown in FIG. 20, when the fixed comb portions 101a to 101d are fixed to the base FD2, the elastic portions 16a to 16d connected to the fixed comb portions 101a to 101d are held in a bent state, and the fixed comb portion 101a is held. ˜101d and the moving comb portions 102a˜102d are displaced. The fixing comb portions 101a to 101d and the base FD2 are fixed by anodic bonding, eutectic bonding, adhesion, or the like.

  As described above, the driving device 1B according to the modification uses the base FD2 having the concave portion UB as the stepped portion, and generates a relative displacement between the fixed comb portions 101a to 101d and the movable comb portions 102a to 102d. .

  The imaging device 70 in the application example may further include a position sensor that measures the position of the imaging element 31.

  Specifically, a position sensor (not shown) for measuring the position of the movable part 7 is arranged in the sealed space of the imaging unit 30, and the position (measurement position) of the movable part 7 is acquired from the position sensor. Then, the current position of the movable part 7 is corrected by comparing the position information with the position (converted position) of the movable part 7 obtained by conversion from the applied voltage. Specifically, when the measurement position and the conversion position are different, feedback control is performed to correct the current position of the movable unit 7 by correcting the applied voltage so that the measurement position matches the conversion position. .

  According to this, it is possible to perform appropriate focus adjustment even in a situation where the operation accuracy of the drive device 1A (1B) deteriorates. As the position sensor, for example, a sensor that measures the distance to the distance measurement object using the reflected light of the laser irradiated to the distance measurement object, or a change in the magnetic flux density between the permanent magnet and the permanent magnet is detected. A magnetic sensor (Hall sensor) using a Hall element to be used can be employed.

  In the application example described above, the image sensor 31 is disposed in the movable portion 7 of the driving device 1A, but the present invention is not limited to this. Specifically, the movable portion 7 of the driving device 1A may be configured by an optical element such as a lens, a mirror, or a diffraction grating.

It is a figure which shows the structure and operation | movement of an electrostatic actuator. It is a figure which shows the structure and operation | movement of an electrostatic actuator. It is a functional block diagram of the drive device concerning this embodiment. It is a top view of the drive device concerning this embodiment. It is a side view of the drive device in the initial state before driving. It is a side view of the drive device in a drive state. It is a figure which shows the initial state and drive state of a drive device. It is a flowchart which shows the manufacturing process of a drive device. It is a figure which shows an SOI substrate. It is a figure which shows the mask patterned on the surface of the formation layer. It is a figure which shows the mask patterned on the surface of the auxiliary | assistant layer. It is explanatory drawing of the manufacturing process of the drive device which concerns on this embodiment. It is explanatory drawing of the manufacturing process of the drive device which concerns on this embodiment. It is explanatory drawing of the manufacturing process of the drive device which concerns on this embodiment. It is a figure which shows the position of convex part TB in base FD1. It is explanatory drawing of the manufacturing process of the drive device which concerns on this embodiment. It is a figure which shows an imaging unit. It is a figure which shows an imaging device provided with an imaging unit. It is explanatory drawing of the manufacturing process of the drive device concerning a modification. It is explanatory drawing of the manufacturing process of the drive device concerning a modification.

Explanation of symbols

1A, 1B Driving device 10a, 10b, 10c, 10d Electrostatic actuator 11 First frame 21 Second frame 101, 101a-101d Fixed comb part 102, 102a-102d Moving comb part 16a-16d Elastic part FD1, FD2 Base TB Convex part UB Concave part

Claims (11)

A driving device for driving the movable part,
A moving comb tooth having a plate surface defined by a first direction and a second direction, and a plurality of first tooth plates having a tooth height direction as the first direction arranged in a third direction at intervals from each other An electrode, and a fixed comb electrode in which a plurality of second tooth plates whose tooth height direction is the first direction are alternately arranged substantially parallel to the plurality of first tooth plates, and the moving comb A driving mechanism in which a tooth electrode gives a driving displacement to the movable part;
Offset means for generating a relative shift between the moving comb electrode and the fixed comb electrode with the second direction as an offset direction;
With
The fixed comb electrode is formed integrally with the moving comb electrode via an elastic portion that can be elastically deformed in the offset direction,
The drive means characterized in that the offset means elastically deforms the elastic part to move the fixed comb electrode in the offset direction to generate the relative displacement. The drive device according to claim 1,
The offset means includes a base having a stepped portion,
In the base, when the base and the drive mechanism are joined, the stepped portion is present at a position to elastically deform the elastic portion and move the fixed comb electrode in the offset direction.
The step portion generates the relative displacement between the fixed comb electrode and the movable comb electrode along with the joining. The drive device according to claim 1 or 2,
The drive device according to claim 1, wherein the movable comb electrode and the fixed comb electrode are fabricated by etching from one direction using one Si layer of two Si layers in an SOI substrate. The drive device according to claim 2 or claim 3,
The driving device according to claim 1, wherein the stepped portion is a convex portion provided on the base. The drive device according to claim 2 or claim 3,
The driving device according to claim 1, wherein the stepped portion is a concave portion provided in the base. The drive device according to any one of claims 1 to 5,
The step of the step portion is equal to or less than the length of the side parallel to the offset direction on the comb tooth surface. The drive device according to any one of claims 1 to 6,
An image pickup device is disposed in the movable part.   The imaging device according to claim 7, wherein the driving device is disposed in an internal space of a single housing.   An imaging device comprising the imaging unit according to claim 8. A method of manufacturing a drive device for driving a movable part,
a) Movement in which a plurality of first tooth plates having a plate surface defined by the first direction and the second direction and having the first direction as the tooth height direction are arranged in the third direction at intervals from each other. A comb-shaped electrode, and a plurality of second tooth plates having a tooth height direction as the first direction, and a fixed comb-shaped electrode in which the plurality of second tooth plates are alternately arranged substantially parallel to the plurality of first tooth plates, A step of integrally forming a drive mechanism in which the movable comb electrode applies drive displacement to the movable part;
b) generating a relative displacement between the moving comb electrode and the fixed comb electrode with the second direction as an offset direction;
In the step a), the fixed comb electrode is integrally formed with the movable comb electrode via an elastic portion that can be elastically deformed in the offset direction.
In the step b), the fixed comb electrode is caused to move in the offset direction by elastically deforming the elastic portion to generate the relative deviation. A driving device for driving the movable part,
A drive mechanism having a movable comb electrode that applies drive displacement to the movable part, and fixed comb electrodes that are alternately arranged on the movable comb electrode;
Offset means for generating a relative shift in the offset direction perpendicular to the extending direction of the comb teeth in the comb tooth surface of the movable comb electrode between the fixed comb electrode and the movable comb electrode;
With
The fixed comb electrode is formed integrally with the moving comb electrode via an elastic portion that can be elastically deformed in the offset direction,
The drive means characterized in that the offset means elastically deforms the elastic part to move the fixed comb electrode in the offset direction to generate the relative displacement.

Images