JP2012044859A - Electrostatic type actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration in working speed and decrease in efficiency in an electrostatic type actuator which is made up of a stator and a mover which have a plurality of comb-like electrodes.SOLUTION: There are provided a stator which has a plurality of first comb-like electrodes and a mover which has a plurality of second comb-like electrodes. Central parts of projecting parts and recessed parts of the plurality of first comb-like electrodes of the stator and central parts of projecting parts and recessed parts of the plurality of second comb-like electrodes of the mover are mutually separated and arranged face to face at prescribed pitches along an arrangement direction of electrodes. An outer peripheral surface of the projecting part of the plurality of first comb-like electrodes and/or an outer peripheral surface of the recessed part of the plurality of first comb-like electrodes constitutes the electrostatic type actuator such as to be covered with an insulating layer made up of a high dielectric of which relative permittivity is 300 or more.

Description

  The present invention relates to an electrostatic actuator that can be suitably used as various actuators such as a head actuator of a hard disk drive, a shutter drive, a micro valve, a manipulator, and a micro robot.

  Various types of electrostatic actuators have been proposed in the past depending on the application. For example, in Patent Document 1, a mover in which a high dielectric member and a low dielectric member are alternately coupled is inserted between a pair of stators provided with a plurality of electrodes, and a multiphase power source is connected to the stator electrode. An electrostatic actuator is disclosed in which a moving element is translated relative to a stator by a traveling wave electric field generated from the multiphase power source.

  Further, Patent Document 2 includes a first member having a plurality of strip electrodes in an insulator and a second member having a plurality of strip electrodes in the insulator, and further to the first member and the second member. An electrostatic actuator for parallel movement is disclosed in which a multiphase power source is provided and a ceramic dielectric is provided on opposite sides of a first member and a second member.

  Further, in Patent Document 3, by applying a voltage between a pair of comb-shaped electrodes made of a conductor, a comb-shaped electrode made of a dielectric material is drawn between a pair of comb-shaped electrodes by an electrostatic force, and translated. It is disclosed to constitute an electrostatic actuator for use. In Patent Document 4, a stator in which a large number of stator electrodes are arranged at a predetermined interval in one direction and a plurality of mover electrodes arranged to face the stator electrodes are arranged at a predetermined interval in the same direction. An air layer for reducing friction, wherein a driving voltage is applied between the stator and the mover via an insulator layer, and the mover is moved in parallel with respect to the stator. An electrostatic actuator for translation that is not provided is disclosed.

JP 2003-224985 Japanese Unexamined Patent Publication No. 20001-178153 JP-A-9-285143 Japanese Patent No. 2899133

  On the other hand, the present inventors have developed an electrostatic actuator comprising a stator and a mover having a plurality of comb-shaped electrodes, unlike the conventional electrostatic actuator described above. In such an electrostatic actuator, a gap made of an air layer is provided between the stator and the mover (a plurality of comb-shaped electrodes) to ensure electrical insulation between each other. However, the dielectric constant of the air layer is low, and when the distance between the stator and the mover is increased, the electrostatic force acting between them is abruptly reduced, the operating speed of the actuator is reduced and the efficiency is reduced. There was a problem that would decrease.

  In order to cope with such a problem, an attempt has been made to increase the voltage applied to the plurality of comb-shaped electrodes constituting the stator and the moving element, that is, the drive voltage. Has limitations and goes against the current energy conservation problems.

  An object of the present invention is to suppress a decrease in operating speed and a decrease in efficiency in an electrostatic actuator composed of a stator and a mover having a plurality of comb-shaped electrodes.

  In order to achieve the above object, an aspect of the present invention includes a stator having a plurality of first comb-shaped electrodes and a mover having a plurality of second comb-shaped electrodes, The convex portions and concave portions of the plurality of first comb-shaped electrodes and the convex portions and concave portions of the plurality of second comb-shaped electrodes of the moving member have respective center portions along the arrangement direction of the electrodes. At least one outer peripheral surface of the plurality of first comb-shaped electrodes and the convex portions of the plurality of second comb-shaped electrodes; The electrostatic actuator is characterized in that the outer peripheral surface of the recess of the plurality of first comb-shaped electrodes is covered with an insulating layer made of a high dielectric material having a relative dielectric constant of 300 or more. .

  According to the electrostatic actuator of this aspect, at least one of the convex portions of the plurality of first comb-shaped electrodes constituting the stator and the convex portions of the plurality of second comb-shaped electrodes constituting the movable member. The outer peripheral surface and / or the outer peripheral surface of the recesses of the plurality of second comb-shaped electrodes constituting the movable element are covered with an insulating layer made of a high dielectric material having a relative dielectric constant of 300 or more. The convex portions of the plurality of first comb-shaped electrodes are opposed to the plurality of second comb-shaped electrodes, and the formation of the high dielectric insulating layer in the portion is that the high dielectric This corresponds to the fact that the substantial distance between the plurality of first comb-shaped electrodes and the plurality of second comb-shaped electrodes is reduced by the effect of the spontaneous polarization action.

  Similarly, the convex portions of the plurality of second comb-shaped electrodes are opposed to the plurality of first comb-shaped electrodes, and it is difficult to form a high dielectric insulating layer in the portion. This corresponds to a reduction in the substantial distance between the plurality of first comb-shaped electrodes and the plurality of second comb-shaped electrodes due to the effect of the spontaneous polarization action of the dielectric.

  Further, the concave portions of the plurality of first comb-shaped electrodes are also opposed to the plurality of second comb-shaped electrodes, and forming a high dielectric insulating layer in the corresponding portion This corresponds to the fact that the substantial distance between the plurality of first comb-shaped electrodes and the plurality of second comb-shaped electrodes is reduced by the effect of the spontaneous polarization action.

  Accordingly, when the substantial distance between the plurality of first comb-shaped electrodes and the second comb-shaped electrodes is reduced, the distance between the electrodes, that is, the distance between the stator and the mover is slightly increased. However, it is possible to suppress a reduction in electrostatic force acting between them, and it is possible to suppress a decrease in operating speed and efficiency as an actuator. For this reason, it is not necessary to increase the voltage applied to the plurality of comb-shaped electrodes constituting the stator and the mover, that is, the driving voltage, and this meets the recent demand for energy saving.

  Note that the convex portions and concave portions of the plurality of first comb-shaped electrodes of the stator and the convex portions and concave portions of the plurality of second comb-shaped electrodes of the mover are respectively arranged in the arrangement direction of the electrodes. In order to actually drive the electrostatic actuator of this embodiment by applying a voltage to the electrodes, as described in detail below, It is what is required.

  In one example of the present invention, the outer peripheral surfaces of both the convex portions of the plurality of first comb-shaped electrodes and the convex portions of the plurality of second comb-shaped electrodes are covered with the insulating layer made of the high dielectric material. Can do.

  According to this example, the substantial distance between the plurality of first comb-shaped electrodes and the plurality of second comb-shaped electrodes facing each other can be further reduced. Even in the case where the moving distance of the moving element is slightly increased, the reduction of the electrostatic force acting between them can be further suppressed, and the operating speed as the actuator can be suppressed from being lowered. . For this reason, it is not necessary to increase the voltage applied to the plurality of comb-shaped electrodes constituting the stator and the mover, that is, the drive voltage, and it is more consistent with the recent demand for energy saving.

  In an example of the present invention, the insulating layer, the outer peripheral surface of at least one of the convex portions of the plurality of first comb-shaped electrodes and the convex portions of the plurality of second comb-shaped electrodes, and / or the plurality of While contacting the boundary with the outer peripheral surface of the said recessed part of a 1st comb-tooth type electrode, a electrically conductive film can be formed along the whole boundary.

  In this case, the gap between the first comb-shaped electrode constituting the stator and the second comb-shaped electrode constituting the movable element is about (5 μm), and the voltage applied between them is (30). When V is about V, electric charges are accumulated in the insulating layer formed on the outer peripheral surface of the first comb-shaped electrode and the insulating layer formed on the outer peripheral surface of the second comb-shaped electrode. Therefore, even when a predetermined voltage is applied to the first comb-shaped electrode and the second comb-shaped electrode, an electrical signal (positive or negative voltage) associated with the applied voltage is applied to the first comb-shaped electrode and the second comb-shaped electrode. 2 may not sufficiently act on the comb-shaped electrode, and the movable element may not be driven relative to the stator in accordance with the electric signal.

  However, by providing the conductive film as described above, the charge charged in the insulating layer of the first comb-shaped electrode and / or the insulating layer of the second comb-shaped electrode is transferred to the first via the conductive film. It can escape to the comb-shaped electrode and / or the second comb-shaped electrode, and the accumulation of charges as described above, that is, charging can be prevented. As a result, when a predetermined voltage is applied to the first comb-shaped electrode 13 and the second comb-shaped electrode 14, an electric signal (positive or negative voltage) accompanying the applied voltage is changed to the first comb-shaped electrode. It is possible to avoid the inconvenience that the actuator 12 does not sufficiently act on the 13 and the second comb-shaped electrode 14 and the movable element 12 is not driven with respect to the stator 11 in accordance with the electric signal.

  In one example of the present invention, the insulating layer includes a leading edge portion on the outer peripheral surface of the convex portion of the plurality of first comb-shaped electrodes and a leading edge on the outer peripheral surface of the convex portion of the plurality of second comb-shaped electrodes. At least one of the portions and / or the upper edge portion on the outer peripheral surface of the concave portion of the plurality of first comb-shaped electrodes can be formed.

  In this example, since the insulating layer is formed at the upper edge portion or the like in the concave portion of the first comb-shaped electrode, most of the first comb-shaped electrode concave portion and the like are exposed. Therefore, the above-described problem of charging the insulating layer can be avoided.

  In addition, since electrostatic force is concentrated on the upper edge portion and the like in the concave portion of the first comb-shaped electrode, if a high dielectric insulating layer is formed at the location, by spontaneous polarization of the insulating layer, It is possible to obtain an effect that the substantial distance between the first comb-shaped electrode and the second comb-shaped electrode is reduced. Accordingly, even when the distance between the first comb-shaped electrode and the second comb-shaped electrode is reduced, the distance between the electrodes, that is, the stator and the mover, is slightly increased. The reduction of the electrostatic force acting between them can be suppressed, and the operation speed and efficiency as the actuator can be suppressed from being lowered.

  In addition, it is not necessary to increase the voltage applied to the first comb-shaped electrode or the like, that is, the drive voltage, so that it meets the recent demand for energy saving.

  In one example of the present invention, the high dielectric is formed on the side surface of the convex portion of at least one of the plurality of first comb-shaped electrodes and the plurality of second comb-shaped electrodes from above to below. An insulating layer can be formed in a taper shape, and the maximum thickness can be made into half or less of the said pitch. That is, as described above, the side surfaces of the convex portions of the insulating layer covering the outer peripheral surfaces of the convex portions of the plurality of first comb-shaped electrodes and the convex portions of the plurality of second comb-shaped electrodes. The insulating layer formed in the above can be formed in a tapered shape so that the maximum thickness of the insulating layer made of the high dielectric is less than half of the pitch from the upper side to the lower side. .

  In the present example, in particular, the maximum thicknesses on both side surfaces of the convex portions of the plurality of first comb-shaped electrodes and / or the plurality of second comb-shaped electrodes constituting the stator and / or the mover are these. The electrode is formed thicker in a tapered shape from the upper side to the lower side so that the pitch is equal to or less than half of the pitch corresponding to the shift of the central part of the convex part (and concave part) of the electrodes arranged opposite to each other. Accordingly, the electrostatic force acting between the electrodes involved in the electrostatic movement of the first comb-shaped electrode constituting the stator and the second comb-shaped electrode constituting the movable element can be increased. At the same time, it is possible to suppress the electrical influence on adjacent comb-shaped electrodes that are not involved in electrostatic movement.

  In an example of the present invention, the plurality of first comb-shaped electrodes constituting the stator and the plurality of second comb-shaped electrodes constituting the movable element are processed by micromachine technology, and the electrostatic actuator is Micro Electro Mechanical Systems (hereinafter referred to as “MEMS”) electrostatic actuators.

  As described above, according to the present invention, a decrease in operating speed and a decrease in efficiency can be suppressed in an electrostatic actuator composed of a stator and a mover having a plurality of comb-shaped electrodes.

It is a figure which shows schematic structure of the comb-tooth type actuator of 1st Embodiment. It is a block diagram which shows the modification of the comb-tooth type actuator of 1st Embodiment. It is a graph which shows the relationship between the distance (displacement) between the 1st comb-tooth type electrode and the 2nd comb-tooth type electrode, and the electrostatic force which acts between these electrodes in 1st Embodiment. It is a figure which shows schematic structure of the rotary stepping motor of 2nd Embodiment. It is a figure which expands and shows the boundary part of a stator and a moving element of the rotary stepping motor shown in FIG. It is a block diagram which shows the characteristic part in the modification of the rotary stepping motor of 2nd Embodiment. It is a graph which shows the relationship between the distance (displacement) between the 1st comb-tooth type electrode and the 2nd comb-tooth type electrode, and the electrostatic force which acts between these electrodes in 2nd Embodiment. It is a figure which shows schematic structure of the stepping motor for parallel movement of 3rd Embodiment. It is a figure which shows schematic structure of the comb-tooth type actuator in 4th Embodiment. It is sectional drawing at the time of cutting along the II line of the comb-shaped actuator shown in FIG. It is a figure which shows schematic structure of the comb-tooth type actuator in 5th Embodiment. It is the result of having analyzed the electrostatic force which acts on the gap between the 1st comb-tooth type electrode in 2nd Embodiment, and the 2nd comb-tooth type electrode by the electromagnetic field finite element method. It is a graph which shows the relationship between the distance (displacement) between the 1st comb-tooth type electrode in 2nd Embodiment, and the 2nd comb-tooth type electrode, and the electrostatic force which acts between these. It is a figure which shows the modification of the comb-tooth type actuator of 5th Embodiment. It is a figure which shows the modification of the comb-tooth type actuator of 5th Embodiment. 12 is a graph showing the pulling force acting between the convex portion of the second comb-shaped electrode and the concave portion of the first comb-shaped electrode of the stator in the comb-shaped actuator shown in FIG. It is a figure which expands and shows the boundary part of a stator and a moving element of the rotary stepping motor in 6th Embodiment. It is a figure which shows the modification of the rotary stepping motor in 6th Embodiment. It is a figure which expands and shows the boundary part of a stator and a moving element of the rotary stepping motor in 7th Embodiment. It is a graph which shows the relationship between the distance (displacement) between the 1st comb-tooth type electrode and the 2nd comb-tooth type electrode of the rotary stepping motor in 7th Embodiment, and the electrostatic force which acts between these electrodes. . It is a figure which shows the modification of the rotary stepping motor of 7th Embodiment. It is a side view of the 1st comb-tooth type electrode and the 2nd comb-tooth type electrode of the rotary stepping motor of a 7th embodiment. It is a graph which shows the leakage state of the electric field from the insulating layer in the modification of 7th Embodiment. Similarly, it is a graph which shows the leakage state of the electric field from the insulating layer in the modification of 7th Embodiment. It is a partial cross section figure which shows schematic structure of the stepping motor for parallel movement in 8th Embodiment. It is a figure which shows schematic structure of the stepping motor for parallel movement in 9th Embodiment.

  The details of the present invention as well as other features and advantages are described below.

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of a comb-shaped actuator according to the present embodiment. In the present embodiment, only the main part of the comb-shaped actuator is shown in order to clarify the features.

  As shown in FIG. 1, the comb-shaped actuator 10 of this embodiment includes a stator 11 and a mover 12. The stator 11 includes a first comb-shaped electrode 13 and an insulating layer 16 made of a high dielectric material having a relative dielectric constant of 300 or more formed on the outer peripheral surface thereof. The mover 12 includes a second comb-shaped electrode 14. As apparent from FIG. 2, the convex portion 14 </ b> A of the second comb-shaped electrode 14 in the moving element 12 is positioned at the center of the concave portion 13 </ b> B of the first comb-shaped electrode 13 in the stator 11. Is arranged. Further, the movable element 12 (second comb electrode 14) is fixed to a fixing member (not shown) via a spring member 18.

  A predetermined voltage is applied between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 from a multiphase DC power source or an AC power source 19. As a result, for example, the stator 11 (first comb-shaped electrode 13) has a negative potential and the mover 12 (second comb-shaped electrode 14) has a positive potential, so that they attract each other. Specifically, the convex portion 14A of the second comb-shaped electrode 14 constituting the movable element 12 is electrostatically drawn into the concave portion 13B of the first comb-shaped electrode 13 constituting the stator 11. As a result, the movable element 12 moves downward toward the stator 11.

  The moving distance of the movable element 12 acts between the concave portion 13B of the first comb-shaped electrode 13 constituting the stator 11 and the convex portion 14A of the second comb-shaped electrode 14 constituting the movable element 12. This is determined by the balance between the electrostatic force to be applied and the biasing force of the spring member 18 connected to the moving element 12.

  In the present embodiment, the outer peripheral surface of the first comb-shaped electrode 13 constituting the stator 11 is covered with an insulating layer 16 made of a high dielectric material having a relative dielectric constant of 300 or more. In this case, since the insulating layer 16 is spontaneously polarized, the substantial distance between the first comb-shaped electrode 11 and the second comb-shaped electrode 13 is reduced. Therefore, as the substantial distance between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 is reduced, the distance between the electrodes, that is, the stator 11 and the mover 12 is somewhat increased. Even in such a case, it is possible to suppress a reduction in electrostatic force acting between them, and it is possible to suppress a decrease in operating speed and efficiency as an actuator. In addition, it is not necessary to increase the voltage applied to the first comb-shaped electrode 13 and the second comb-shaped electrode 14 constituting the stator 11 and the moving element 12, that is, the driving voltage, and the recent demand for energy saving is also eliminated. Matches.

  In addition, since the insulating layer 16 is formed on the outer peripheral surface of the first comb-shaped electrode 13, the insulating layer 16 serves as an electrostatic shield layer even when the movable element 12 moves down excessively. Since it comes to function, the electrical contact between electrodes and the discharge between electrodes can be suppressed.

The high dielectric material constituting the insulating layer 16 may be either inorganic or organic as long as the relative dielectric constant is 300 or more, preferably 1000 or more, but the inorganic high dielectric material has the above-mentioned relative dielectric constant. So-called ferroelectrics are known and are preferred because they are easily available and manufactured. Examples of such inorganic high-dielectrics include general-purpose strong materials such as barium titanate (BaTiO ₃ : relative dielectric constant of about 5000) and lead zirconate titanate (Pb (Zr, Ti) O ₃ : relative dielectric constant of about 300). Mention may be made of dielectrics. In addition, the relative dielectric constant of barium titanate and lead zirconate titanate is shown as a representative value, and even if it is the same material, it changes with manufacturing methods.

  FIG. 2 corresponds to a modification of the above embodiment. In this modification, the same insulating layer 16 as that of the first comb-shaped electrode 13 is formed on the outer peripheral surface of the convex portion 14A of the second comb-shaped electrode 14 constituting the movable element 12, It is different from the above embodiment.

  In this modification, since the insulating layer 16 is also formed on the outer peripheral surface of the convex portion 14A of the second comb-shaped electrode 14, the first comb-shaped electrode 11 and the first comb-shaped electrode 11 are formed by spontaneous polarization of the insulating layer 16. The substantial distance from the second comb-shaped electrode 13 is further reduced. Therefore, as the substantial distance between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 is further reduced, the distance between the electrodes, that is, the stator 11 and the mover 12 is slightly increased. Even in such a case (in the etching by MEMS DRIE, there is a taper and a dimensional error of about 0.1 to 0.5 μm occurs), it is possible to further suppress the reduction of the electrostatic force acting between them. As a result, it is possible to further suppress the decrease in the operation speed.

  Since other features and operational effects are the same as those in the above embodiment, description thereof is omitted.

  The comb-shaped actuator according to the present embodiment can be used as, for example, a shutter or a mirror driving device.

  In addition, the size of the comb-shaped actuator 10 of the present embodiment is not particularly limited. However, as described below, the first comb-shaped electrode 13 and the second comb-shaped electrode 14 are connected to a micromachine. The comb-shaped actuator 10 can be configured as a MEMS by processing according to technology and changing the size of each member from the μm order to the sub-μm order.

  FIG. 3 shows the distance (displacement) between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 and the electrostatic force acting between these electrodes of the comb-shaped actuator 10 in the present embodiment. It is a graph which shows a relationship.

  The height H1 of the convex portion 13A of the first comb-shaped electrode 13 was 25 μm, the thickness T1 was 5 μm, and the width W1 of the concave portion 13B was 11 μm. Further, the height h1 of the convex portion 14A of the second comb-shaped electrode 14 was 20 μm, and the wall thickness t1 was 5 μm. The first comb-shaped electrode 13 and the second comb-shaped electrode 14 were made of (silicon).

  Further, in the embodiment shown in FIG. 1, an insulating layer 16 made of barium titanate is formed on the outer peripheral surface of the first comb-shaped electrode 13 to a thickness of 2 μm. In the embodiment shown in FIG. An insulating layer 16 made of barium titanate was formed to a thickness of 1 μm on each of the outer peripheral surface of the tooth-shaped electrode 13 and the outer peripheral surface of the convex portion 14A of the second comb-shaped electrode 14.

  As is apparent from FIG. 3, when the insulating layer 16 is not formed, the first comb-shaped electrode 13 (stator 11) and the second comb-shaped electrode 14 (moving element 12) over the entire displacement. ) Is small, but it can be seen that the formation of the insulating layer 16 significantly increases the electrostatic force. Therefore, even when the distance between the stator 11 and the mover 12 is slightly increased, the reduction of the electrostatic force acting between them can be suppressed, and the operating speed and efficiency as the actuator are reduced. It turns out that it can suppress.

  In addition, the electrostatic force shown in FIG. 3 is the result analyzed by the electromagnetic field finite element method. When the gap distance is doubled, the electrostatic force is halved. Therefore, it is important to reduce the gap distance. However, since the actuator unit moves, the gap distance cannot be reduced in order to ensure insulation. In this proposal, even if the gap distance is normal (in high-precision MEMS), the electrostatic force can be increased about twice by forming a high dielectric constant film of 1 μm on both electrodes.

(Second Embodiment)
FIG. 4 is a view showing a schematic configuration of the rotary stepping motor in the present embodiment, and FIG. 5 is an enlarged view showing a boundary portion between the stator and the mover of the rotary stepping motor shown in FIG.

  As shown in FIG. 4, in the rotary stepping motor 20 of the present embodiment, a stator 29 and a mover 22 are arranged concentrically, and the stator 29 is located outside the mover 22 and will be described below. Thus, the moving element 22 rotates inside the stator 29.

  An interconnect member 25 made of, for example, silicon is provided on the inner side of the mover 22, and an arcuate outer peripheral portion 25 </ b> B is provided on the inner side of the mover 22. Further, in order to support the movable element 22 with a four-stage spring, the fixed end 21 has a convex portion 21A. Furthermore, the movable element 22 also has a fan-shaped convex portion 22A that protrudes inward.

  Also, a pair of plate-like first spring members 28-1 are provided so as to connect the convex portion 21A and the interconnect member 25C, and a pair of plate-like second spring members 28-2 and third. The spring member 28-3 is provided so as to connect the central portion 25A of the interconnect member 25 and the outer peripheral portion 25B. Further, a pair of plate-like fourth spring members 28-4 are provided so as to connect the convex portion 22A of the movable element 22 and the interconnect member 25D.

  The rotational movement of the movable element 22 with respect to the stator 29 is determined by the balance between the electrostatic force generated between the comb-shaped electrodes described below and the urging force of the movable element 22 and the spring members 28-1 to 28-4. Is done.

  As shown in FIG. 5, the stator 29 has first comb-shaped electrodes 23-1 to 23-3 so as to face the mover 22, and the mover 22 is connected to the stator 29. The second comb-shaped electrodes 24-1 to 24-3 are provided so as to oppose each other. Further, the outer peripheral surfaces of the first comb-shaped electrodes 23-1 to 23-3 and the outer peripheral surfaces of the second comb-shaped electrodes 24-1 to 24-3 are made of a high dielectric material having a relative dielectric constant of 300 or more. An insulating layer 26 is formed. However, if the insulating layer 26 is formed on the outer peripheral surface of any one of the first comb-shaped electrodes 23-1 to 23-3 and the second comb-field electrodes 24-1 to 24-3, The effect of this invention can be show | played.

  In the present embodiment, the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3 are the circumferential surfaces of the stator 29 and the mover 22, respectively. Since these electrodes are directly provided on the upper surface, these electrodes themselves constitute electrode protrusions.

  Further, as apparent from FIG. 5, the pitch of the first comb-shaped electrodes 23-1 to 23-3 is based on the driving method of the moving element 22 to be described below with respect to the stator 29. It is set to be slightly larger than the pitch of the comb-shaped electrodes 24-1 to 24-3.

  In FIG. 5, in order to clearly and concisely show the features of the present invention and the motor driving method, only the three comb teeth 233-1 to 23-3 are shown and the second comb-shaped electrodes are shown. Although only three of comb-shaped electrodes 24-1 to 24-3 are shown, in practice, the first comb-shaped electrode is formed over the entire circumferential surface of the stator 29. The second comb-shaped electrode is also formed over the entire circumferential surface of the movable element 22.

  The moving element 22 shown in FIGS. 4 and 5 is moved with respect to the stator 29, for example, as follows. Initially, when a predetermined voltage is applied to the first comb-shaped electrode 23-1 of the stator 29, this electrode becomes a positive potential or a negative potential, and the first comb-shaped electrode 23 of the moving element 22. -1 and the second comb field type electrode 24-1 closest to each other, an electrostatic force is generated. As a result, the second comb-shaped electrode 24-1 is attracted to the first comb-shaped electrode 23-1, and accordingly, the movable element 22 also moves in the same direction.

  Next, when the voltage applied to the first comb-shaped electrode 23-1 is released and a predetermined voltage is applied to the adjacent first comb-shaped electrode 23-2, the first comb-shaped electrode 23. −2 similarly becomes a positive potential or a negative potential, and generates an electrostatic force between the first comb-teeth-type electrode 23-2 and the second comb-field-type electrode 24-2 closest to the mover 22. It becomes like this. As a result, the second comb-shaped electrode 24-2 is attracted to the first comb-shaped electrode 23-2, and accordingly, the movable element 22 also moves in the same direction.

  Further, when the voltage applied to the first comb-shaped electrode 23-2 is released and a predetermined voltage is applied to the adjacent first comb-shaped electrode 23-3, the first comb-shaped electrode 23 −3 similarly becomes a positive potential or a negative potential, and generates an electrostatic force between the first comb-teeth electrode 23-3 of the moving element 22 and the second comb-field electrode 24-3 closest to the mover 22. It becomes like this. As a result, the second comb-shaped electrode 24-3 is attracted to the first comb-shaped electrode 23-3, and accordingly, the movable element 22 also moves in the same direction.

  As a result of the operation as described above, the movable element 22 rotates counterclockwise with respect to the stator 29.

  Although not specifically described in detail, in order to rotate the moving element 22 clockwise with respect to the stator 29, the first comb-type electrodes 23-1 to 23-3 as described above are sequentially arranged. Instead of applying a voltage to the first comb-shaped electrodes 23-3 to 23-1, the voltage may be sequentially applied. That is, the order of voltage application may be reversed. In this example, the movement is controlled by one set of three sets, but the number of sets may be increased as long as it is three sets or more.

  In the present embodiment, the outer surfaces of the first comb-shaped electrodes 23-1 to 23-2 constituting the stator 29 and the second comb-shaped electrodes 24-1 to 24-3 constituting the movable element 22. The outer peripheral surface is covered with an insulating layer 26 made of a high dielectric material having a relative dielectric constant of 300 or more. In this case, since the insulating layer 26 is spontaneously polarized, the substantial distance between the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3 is reduced. Will be. Accordingly, as the substantial distance between the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3 is reduced, these electrodes, that is, the stator 29 and Even when the moving distance of the moving element 22 is somewhat increased, it is possible to suppress a reduction in electrostatic force acting between them, and to suppress a decrease in operating speed and efficiency as an actuator. Can do.

  Further, the voltage applied to the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3 constituting the stator 29 and the mover 22, that is, the drive voltage is increased. It is no longer necessary to meet the demands for energy conservation.

  Note that since the insulating layer 26 functions as an electrostatic shield layer, electrical contact between the electrodes and discharge between the electrodes can be suppressed.

  The insulating layer 26 can be composed of the same material as the insulating layer 16 in the first embodiment.

  FIG. 6 corresponds to a modification of the above embodiment. In this modification, the insulating layer 26 is formed in a tapered shape from the upper side to the lower side on the side surfaces of the second comb-shaped electrodes 24-1 to 24-3 constituting the moving element 22, and the maximum thickness thereof. The height is set to be equal to or less than half the pitch P between the first comb-shaped electrode and the second comb-shaped electrode (in FIG. 6, only the second comb-shaped electrode 24-1 is shown). That is, the side surface portion of the insulating layer 26 covering the outer peripheral surface of the second comb-shaped electrodes 24-1 to 24-3 is directed downward from the upper side thereof, and the maximum thickness thereof is less than half of the pitch P. Thus, it can form in a taper shape.

  Therefore, the first comb-shaped electrodes 23-1 to 23-3 of the stator 29 and the second comb-shaped electrodes 24-1 to 24-3 of the movable element 22 are involved in electrostatic movement. The electrostatic force acting between them can be increased, and the electrical influence on adjacent comb-shaped electrodes that are not involved in electrostatic movement can be suppressed. As a result, it is possible to more effectively suppress the rotational movement of the moving element 22 relative to the stator 29, that is, the reduction in the operating speed and efficiency as an actuator.

  The rotary stepping motor 20 of the present embodiment can be used as a MEMS rotary actuator, for example, as an actuator that rotates a head of a hard disk drive minutely.

  In addition, the size of the rotary stepping motor 20 of the present embodiment is not particularly limited, but as described below, the first comb-shaped electrodes 23-1 to 23-3 and the second comb are used. The rotary stepping motor 20 can be configured as a MEMS by processing the tooth-type electrodes 24-1 to 24-3 using a micromachine technique and changing the size of each member from the μm order to the sub-μm order.

  FIG. 7 shows the distance (displacement) between the first comb-shaped electrode 23-1 and the second comb-shaped electrode 24-1 and the static electricity acting between these electrodes of the rotary stepping motor 20 in this embodiment. It is a graph which shows the relationship with force.

  The first comb-shaped electrode 23-1 and the second comb-shaped electrode 24-1 had a height of 10 μm and a width of 5 μm. The first comb-shaped electrode 23-1 and the second comb-shaped electrode 24-1 were made of silicon.

  As is clear from FIG. 7, when the insulating layer 26 is not formed, the first comb-shaped electrode 23-1 (stator 21) and the second comb-shaped electrode 24-1 over the entire displacement. Although the electrostatic force acting on the (moving element 22) is small, it can be seen that the formation of the insulating layer 26 significantly increases the electrostatic force. In particular, it can be seen that the electrostatic force increases as the thickness of the insulating layer 26 covering the first comb-shaped electrode 23-1 and / or the second comb-shaped electrode 24-1 increases. .

  As a result, even when the distance between the stator 21 and the mover 22 is slightly increased, the reduction of the electrostatic force acting between them can be suppressed, and the operating speed and efficiency as the actuator are reduced. It can be seen that it can be suppressed. However, when the insulating layer 26 is formed to a thickness of 0.5 μm with respect to the first comb-shaped electrode 23-1, the first comb-shaped electrode 23-1 and the second comb-shaped electrode 24- No difference in the generated electrostatic force is observed when the insulating layer 26 is formed to a thickness of 0.25 μm for both of the above.

  Note that the electrostatic force shown in FIG. 7 is the result of analysis by the electromagnetic field finite element method. When the gap distance is doubled, the electrostatic force is halved. Therefore, it is important to reduce the gap distance. However, since the actuator unit moves, the gap distance cannot be reduced in order to ensure insulation. In the present proposal, even when the gap distance is normal (in high-precision MEMS), the electrostatic force can be increased by a factor of about 2 by forming a 0.25 μm high dielectric constant film on both electrodes.

(Third embodiment)
FIG. 8 is a diagram showing a schematic configuration of a stepping motor for parallel movement in the present embodiment.

  As shown in FIG. 8, the stepping motor 30 of this embodiment includes a stator 31 and a mover 32. The stator 31 is provided with the first comb-shaped electrodes 33-1 to 33-3 as a set, and such sets of electrodes are sequentially provided from the right side to the left side of the drawing. The movable element 32 includes the second comb-shaped electrodes 34-1 to 34-3 as a set, and such sets of electrodes are sequentially provided from the right side to the left side in the drawing. The first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3 are arranged in parallel to each other.

  Further, the outer peripheral surfaces of the first comb-shaped electrodes 33-1 to 33-3 and the outer peripheral surfaces of the second comb-shaped electrodes 34-1 to 34-3 are formed by an insulating layer 36 made of a high dielectric material. It is covered.

  However, if the insulating layer 36 is formed on the outer peripheral surface of one of the first comb-shaped electrodes 33-1 to 33-3 and the second comb-field electrodes 34-1 to 34-3, The effect of this invention can be show | played.

  The right end of the mover 32 is fixed to the stator 31 by a spring member 38. Therefore, the moving distance of the moving element 32 is determined by the electrostatic force acting between the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3, and the moving element 32. It is determined by the balance with the urging force with the spring member 38 connected to.

  To move the mover 32 shown in FIG. 8 with respect to the stator 31, for example, the following is performed. First, when a predetermined voltage is applied to the first comb-shaped electrode 33-1 of the stator 31, this electrode becomes a positive potential or a negative potential, and the first comb-shaped electrode 33 of the mover 32. -1 and the second comb field type electrode 34-1 closest to each other, an electrostatic force is generated. As a result, the second comb-shaped electrode 34-1 is attracted to the first comb-shaped electrode 33-1 and the moving element 32 is also moved in the same direction (in FIG. The comb-shaped electrode 33-1 and the second comb-shaped electrode 34-1 are opposed to each other).

  Next, when the voltage applied to the first comb-shaped electrode 33-1 is released and a predetermined voltage is applied to the adjacent first comb-shaped electrode 33-2, the first comb-shaped electrode 33. −2 similarly becomes a positive potential or a negative potential, and generates an electrostatic force between the first comb-teeth electrode 33-2 and the second comb-field electrode 34-2 closest to the slider 32. It becomes like this. As a result, the second comb-shaped electrode 34-2 is attracted to the first comb-shaped electrode 33-2, and accordingly, the movable element 32 also moves in the same direction.

  Furthermore, when the voltage applied to the first comb-shaped electrode 33-2 is released and a predetermined voltage is applied to the adjacent first comb-shaped electrode 33-3, the first comb-shaped electrode 33 is applied. −3 similarly becomes a positive potential or a negative potential, and an electrostatic force is generated between the first comb-shaped electrode 33-3 and the second comb-field electrode 34-3 closest to the movable element 32. It becomes like this. As a result, the second comb-shaped electrode 34-3 is attracted to the first comb-shaped electrode 33-3, and accordingly, the movable element 32 also moves in the same direction.

  As a result of the above operation, the mover 32 moves to the left with respect to the stator 21. In this example, the movement is controlled by one set of three sets, but the number of sets may be increased if it is three sets or more.

  In the present embodiment, the outer surfaces of the first comb-shaped electrodes 33-1 to 33-3 constituting the stator 31 and the second comb-shaped electrodes 34-1 to 34-3 constituting the movable element 32 are used. The outer peripheral surface is covered with an insulating layer 36 made of a high dielectric material having a relative dielectric constant of 300 or more. In this case, since the insulating layer 36 is spontaneously polarized, the substantial distance between the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3 is reduced. Will be. Therefore, as the substantial distance between the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3 is reduced, these electrodes, that is, the stator 31 and Even when the moving distance of the moving element 32 is somewhat increased, it is possible to suppress a reduction in electrostatic force acting between them, and to suppress a decrease in operating speed and efficiency as an actuator. Can do.

  Further, the voltage applied between the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3 constituting the stator 31 and the moving element 32, that is, the drive voltage is set. There is no need to increase it, and it will meet the recent demands for energy conservation.

  In addition, since the insulating layer 36 comes to function as an electrostatic shield layer, electrical contact between the electrodes and discharge between the electrodes can be suppressed. Further, as shown in paragraph 0058, the insulating layer 36 can be formed in a tapered shape to increase the efficiency.

  The insulating layer 36 can be composed of the same material as the insulating layer 16 in the first embodiment.

  The stepping motor 30 for parallel movement of this embodiment can be used for (micro robot, micro valve) etc., for example.

  Further, the size of the stepping motor 30 of the present embodiment is not particularly limited. However, as described below, the first comb-shaped electrodes 33-1 to 33-3 and the second comb teeth are used. The stepping motor 30 can be configured as a MEMS by processing the mold electrodes 34-1 to 34-3 by micromachine technology and changing the size of each member from the μm order to the sub μm order.

(Fourth embodiment)
FIG. 9 is a diagram illustrating a schematic configuration of the comb-shaped actuator according to the present embodiment, and FIG. 10 is a cross-sectional view taken along the line II of the comb-shaped actuator illustrated in FIG.

  As shown in FIG. 9 and FIG. 10, the comb-shaped actuator 40 of the present embodiment is the first comb-tooth constituting the stator 11 in the comb-shaped actuator 20 of FIG. 2 of the first embodiment. 2 except that the conductive film 42 is formed along the boundary 41 and in contact with the boundary 41 between the mold electrode 13 and the insulating layer 16 formed so as to cover the outer peripheral surface thereof. The same configuration as that of the comb-shaped actuator 10 shown is adopted.

  In general, the gap between the first comb-shaped electrode 13 constituting the stator 11 and the second comb-shaped electrode 14 constituting the movable element 12 is about 5 μm, and the voltage applied between them is about 30V. Then, charges are accumulated in the insulating layer 16 formed on the outer peripheral surface of the first comb-shaped electrode 13 and the insulating layer 16 formed on the outer peripheral surface of the second comb-shaped electrode 14 constituting the movable element 12. It becomes like this. Therefore, for example, even when a predetermined voltage is applied to the first comb-shaped electrode 13 and the second comb-shaped electrode 14 from the multiphase DC power supply or the AC power supply 19, an electrical signal (positive or negative) associated with the applied voltage is applied. Voltage) does not sufficiently act on the first comb-shaped electrode 13 and the second comb-shaped electrode 14, and the movable element 12 does not drive the stator 11 in accordance with the electrical signal. May end up.

  However, in the present embodiment, since the conductive film 42 is provided as described above, the charge charged on the insulating layer 16 of the first comb-shaped electrode 13 is transferred to the first comb teeth via the conductive film 42. It is possible to escape to the mold electrode 13 and to prevent the accumulation of electric charges as described above, that is, charging. As a result, even when a predetermined voltage is applied to the first comb-shaped electrode 13 and the second comb-shaped electrode 14 from the multiphase DC power supply or the AC power supply 19, an electrical signal (positive or negative) associated with the applied voltage is applied. Voltage) does not sufficiently act on the first comb-shaped electrode 13 and the second comb-shaped electrode 14, and the movable element 12 does not drive the stator 11 in accordance with the electrical signal. It is possible to avoid the inconvenience of being lost.

  In the present embodiment, the conductive film 42 is provided only on the first comb-shaped electrode 13, but the above-described effects can be further increased by providing a conductive film on the second comb-shaped electrode 14. Can be made.

  The conductive film 42 can be composed of, for example, a metal such as gold, platinum, or aluminum, graphene, or an assembly of metal-type carbon nanotubes.

  When the conductive film 42 is formed from a metal, it can be formed by using vapor phase growth, vapor deposition, sputtering, MBE, chemical solution method, solution coating method, or the like. In the case where the conductive film 42 is formed from graphene, the graphene can be formed by a CVD method on a copper or nickel plate processed into a target shape pattern and then transferred. When the conductive film 42 is formed from carbon nanotubes, it can be formed in the form of a dispersion film using a method of dispersing in a solvent using a dispersant, a gas phase filtration method, a transfer method, or the like.

  The driving method and other features of the comb-shaped actuator 40 of this embodiment are the same as those of the comb-shaped actuator 10 shown in FIG.

(Fifth embodiment)
FIG. 11 is a diagram showing a schematic configuration of the comb-shaped actuator according to the present embodiment.
As shown in FIG. 11, the comb-shaped actuator 50 of the present embodiment is the same as the first comb-shaped electrode 13 constituting the stator 11 in the comb-shaped actuator 10 shown in FIG. 2 of the first embodiment. Instead of forming the insulating layer 16 so as to cover the outer peripheral surface of the first comb-shaped electrode 13, the insulating layer 16 is provided only at the upper edge portion of the recess 13 </ b> B of the first comb-shaped electrode 13, thereby forming the moving element 12. Instead of forming the insulating layer 16 so as to cover the outer peripheral surface of the comb-shaped electrode 14, the insulating layer 16 is provided only at the tip of the convex portion 14A of the second comb-shaped electrode 14.

  Although not specifically shown in the drawing, these insulating layers 16 are formed over the entire depth direction perpendicular to the paper surface of the recess 13B of the first comb-shaped electrode 13, and similarly, It is formed over the entire depth direction perpendicular to the paper surface of the convex portion 14A of the second comb-shaped electrode 14.

  FIG. 12 shows the result of analyzing the electrostatic force acting on the gap between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 by the electromagnetic field finite element method. The height H1 of the convex portion 13B of the first comb-shaped electrode 13 was 20 μm, and the thickness T1 was 5 μm. Further, the height h1 of the convex portion 14A of the second comb-shaped electrode 14 was 20 μm, and the wall thickness t1 was 5 μm. The first comb-shaped electrode 13 and the second comb-shaped electrode 14 were made of silicon.

  As is clear from FIG. 12, the electrostatic force acting on the gap between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 is the upper edge portion of the recess 13 </ b> B of the first comb-shaped electrode 13. And it turns out that it is large in the front-end | tip part of the convex part 14A of the 2nd comb-tooth type electrode 14. FIG.

  That is, if the high dielectric insulating layer 16 is formed in such a portion where the action of electrostatic force is large, the first comb-shaped electrode 11 and the second comb-shaped electrode are caused by the spontaneous polarization of the insulating layer 16. The effect that the substantial distance with 13 is reduced can be obtained. Therefore, as the substantial distance between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 is reduced, the distance between the electrodes, that is, the stator 11 and the mover 12 is somewhat increased. Even in such a case, it is possible to suppress a reduction in electrostatic force acting between them, and it is possible to suppress a decrease in operating speed and efficiency as an actuator.

  In addition, it is not necessary to increase the voltage applied to the first comb-shaped electrode 13 and the second comb-shaped electrode 14 constituting the stator 11 and the moving element 12, that is, the driving voltage, and the recent demand for energy saving is also eliminated. Matches.

  As described above, when the gap between the stator 11 and the movable element 14 is about 5 μm and the voltage applied between them is about 30 V, the insulation formed on the outer peripheral surface of the first comb-shaped electrode 13 Charges are accumulated in the insulating layer formed on the outer peripheral surface of the second comb-shaped electrode 14 constituting the layer and the mover 12. Therefore, when the insulating layer is formed over the entire outer peripheral surface, for example, a predetermined voltage is applied to the first comb-shaped electrode 13 and the second comb-shaped electrode 14 from a multiphase DC power source or an AC power source 19. In this case, an electrical signal (positive or negative voltage) accompanying the applied voltage does not sufficiently act on the first comb-shaped electrode 13 and the second comb-shaped electrode 14, and the same as the electrical signal. The mover 12 may not be driven with respect to the stator 11 in some cases.

  However, in the present embodiment, since the insulating layer 16 is provided only at the upper edge portion of the concave portion 13B of the first comb-shaped electrode 13 and the tip portion of the convex portion of the second comb-shaped electrode 14, Since the surface distance of the insulating layer 16 can be reduced, charge retention is reduced. Therefore, the above-described problem of charging of the insulating layer 16 can be avoided, and the above-described effect (provided that the electrostatic force can be reduced by increasing the distance and the effect of providing the insulating layer 16 can be seen from the graph of the result shown in FIG. It is possible to achieve a reduction in operating speed and efficiency).

  In order to more effectively achieve the operational effects of the present embodiment, the height (width H2) of the insulating layer 16 formed at the upper edge portion of the concave portion of the first comb-shaped electrode 13 is the first The height H1 of the convex portion 13A of the comb-shaped electrode 13 is preferably in a range of 1 / 4H1 to 1 / 10H1. Similarly, the width t2 of the insulating layer 16 formed at the tip of the convex portion of the second comb-shaped electrode 14 is ½ of the thickness t1 of the convex portion 14A of the first comb-shaped electrode 14. It is preferable to be in the range of ˜1 / 10.

13 simulates the relationship between the distance between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 and the electrostatic force acting between them under the same conditions as when the results shown in FIG. 12 were simulated. It is a graph at the time of doing. However, the height H2 of the insulating layer 16 formed at the upper edge portion of the concave portion 13B of the first comb-shaped electrode 13 is 3 μm, and the insulating layer 16 is formed at the tip of the convex portion 14A of the second comb-shaped electrode 14. The width t2 of the layer 16 was 3 μm. Furthermore, the insulating layer 16 is made of BaTiO _{3 having a} thickness of 2 μm, and a case where a voltage of 1 V is applied between the first comb-shaped electrode 13 and the second comb-shaped electrode 14 is shown.

  As shown in FIG. 13, in this embodiment, the insulating layer 16 is provided only at the upper edge portion of the concave portion 13B of the first comb-shaped electrode 13 and the tip portion of the convex portion 14A of the second comb-shaped electrode 14. In this case, the first comb-shaped electrode 13 and the second comb-shaped electrode 14 with respect to the displacement between them, specifically, the second comb-shaped electrode 14, that is, the displacement of the movable element 12. The electrostatic force acting between 14 is larger than the case where the insulating layer 16 is provided on the outer peripheral surface of the first comb-shaped electrode 13 and the outer peripheral surface of the convex portion 14A of the second comb-shaped electrode 14. .

  This is because, as shown in FIG. 12, the magnitude of the electrostatic force acting between the two electrodes is mainly the upper edge portion of the concave portion 13B of the first comb-shaped electrode 13 and the convexity of the second comb-shaped electrode 14. This is considered to be due to the fact that the tip portion of the portion 14A becomes large and, as described above, there are few driving obstacles due to the magnitude of the charge of the insulating layer 16.

  FIG. 14 is a modification of the embodiment shown in FIG. This modification is different from the embodiment shown in FIG. 11 in that an additional conductive film 52 is provided on the upper surface and the lower surface of the insulating layer 16 provided at the upper edge portion of the recess 13B of the first comb electrode 13. To do. In this case, charging of the insulating layer 16 at the upper edge portion of the recess 13B of the first comb-shaped electrode 13 can also be effectively removed. Therefore, the disadvantage caused by the above-described charging of the insulating layer 16 can be eliminated.

  The additional conductive film 52 includes the first comb-shaped electrode 13 constituting the stator 11 and the outer periphery thereof as shown in the comb-shaped actuator 40 illustrated in FIGS. 9 and 10 of the fourth embodiment. It is in contact with the boundary with the insulating layer 16 formed so as to cover the surface and along the boundary.

  Further, in order to ensure the strength of the insulating layer 16, the end portion 16A of the insulating layer 16 may be extended to the upper side surface of the second comb electrode 14 as shown in FIG.

  The additional conductive film 52 can be formed in the same manner as the conductive film 42.

  FIG. 13 shows a similar simulation result. In this simulation, when the additional conductive film 52 is provided, the electrostatic force varies depending on the degree of displacement compared to the case where the additional conductive film 52 is not provided. It has not changed significantly.

  FIG. 16 shows the relationship between the convex portion 14A of the second comb-shaped electrode 14 of the moving element 12 and the concave portion 13B of the first comb-shaped electrode 13 of the stator 11 in the comb-shaped actuator 50 shown in FIG. It is the graph which showed the drawing-in force which acts between it with respect to the displacement in the width direction of the recessed part 13B of 14 A of convex parts. The conditions in this simulation were also the same as the conditions when the graph shown in FIG. 13 was obtained.

  In a tooth-type actuator having only electrodes, if the left / right balance of the convex portion 14A with respect to the concave portion 13B is slightly broken due to the influence of disturbance or the like, a phenomenon occurs in which both adhere to each other. However, in the comb-shaped actuator 50 shown in FIG. 11, the insulating layer 16 is only formed on the upper edge portion of the first comb-shaped electrode 13 and so on, and as shown in FIG. It can be seen that even when the is displaced in the width direction in the recess 13B, the pulling force acting between the two is small. Therefore, even when the convex portion 14A fluctuates relatively greatly in the concave portion 13B, adhesion between the two can be suppressed.

  The driving method and other features of the comb-shaped actuator 50 of the present embodiment are the same as those of the comb-shaped actuator 10 shown in FIG.

(Sixth embodiment)
FIG. 17 is an enlarged view of the boundary portion between the stator and the mover of the rotary stepping motor according to the present embodiment.

  As shown in FIG. 17, the rotary stepping motor 60 of the present embodiment is the same as that of the rotary stepping motor 20 of the second embodiment shown in FIGS. 4 and 5. The rotary stepping motor 20 shown in FIG. 4 and FIG. 5 except that the conductive film 62 is formed so as to be in contact with and along the boundary 61 between 23-1 to 23-3 and the insulating layer 26. The same configuration is adopted.

  In general, the gap between the first comb-shaped electrodes 23-1 to 23-3 constituting the stator 29 and the second comb-shaped electrodes 24-1 to 24-3 constituting the moving element 22 is about 5 μm. When the voltage applied between them becomes about 30 V, the insulating layer 16 and the second comb-shaped electrode 24-1 formed on the outer peripheral surface of the first comb-shaped electrodes 23-1 to 23-3. Charges are accumulated in the insulating layer 16 formed on the outer peripheral surface of ˜24-3. Therefore, even when a predetermined voltage is applied to the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3, an electrical signal ( (Positive and negative voltage) does not sufficiently act on the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3, and according to the electrical signal In some cases, the movable element 22 may not be driven with respect to the stator 29.

  However, in the present embodiment, since the conductive film 62 is provided as described above, the electric charge charged in the insulating layer 16 of the first comb-shaped electrodes 23-1 to 23-3 passes through the conductive film 62. Thus, the first comb-shaped electrodes 23-1 to 23-3 can be released, and the accumulation of charges as described above, that is, charging can be prevented. As a result, even when a predetermined voltage is applied to the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3, an electrical signal associated with the applied voltage is obtained. (Positive and negative voltages) do not sufficiently act on the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3, and the electric signals In addition, it is possible to avoid the inconvenience that the movable element 22 is not driven with respect to the stator 29.

  In the present embodiment, the conductive film 62 is provided only on the first comb-shaped electrodes 23-1 to 23-3, but the conductive film 62 is further provided on the second comb-shaped electrodes 24-1 to 24-3. By providing the above, the above-described effects can be further increased.

The conductive film 62 can be formed in the same manner as the conductive film 42 in the fourth embodiment.
Note that the driving method and other features of the rotary stepping motor 60 of the present embodiment are the same as those of the rotary stepping motor 20 shown in FIGS.

(Seventh embodiment)
FIG. 18 is an enlarged view of the boundary portion between the stator and the mover of the rotary stepping motor according to the present embodiment.

  As shown in FIG. 18, the rotary stepping motor 70 of the present embodiment is a first comb-shaped electrode constituting the stator 29 in the rotary stepping motor 20 of the second embodiment shown in FIGS. 4 and 5. Instead of forming the insulating layer 16 so as to cover the outer peripheral surfaces 23-1 to 23-3, only the upper edge portion (of the convex portion) of the first comb-shaped electrodes 23-1 to 23-3 is formed. Instead of providing the insulating layer 26 and forming the insulating layer 16 so as to cover the outer peripheral surfaces of the second comb-shaped electrodes 24-1 to 24-3 constituting the moving element 22, the second comb-shaped The insulating layer 26 is provided only on the upper edge portion of the (convex portion) of the electrodes 24-1 to 24-3.

  Although not specifically shown in the figure, these insulating layers 26 are formed over the entire depth direction perpendicular to the paper surface of the first comb-shaped electrodes 23-1 to 23-3. In addition, the second comb-shaped electrodes 24-1 to 24-3 are formed over the entire depth direction perpendicular to the paper surface.

  Further, the tip of the insulating layer 26 is not necessarily at the same level as the top surface of the first comb-shaped electrodes 23-1 to 23-3 and the like, and the first comb-shaped electrodes 23-1 to 23-23. As long as the tip of the insulating layer 26 provided on -3 does not contact the tip of the insulating layer 26 provided on the second comb-shaped electrodes 24-1 to 24-3, the tip may protrude from the upper surface described above. . The protruding amount of the insulating layer 26 is in the range of 1/10 to 1/2 of the gap between the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3. It can be.

  Further, as shown in FIG. 19, the protruding portion 26A may be formed up to the upper portion of the electrode in order to maintain the strength of the film.

  In the present embodiment, the electrostatic force acting between the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3 is applied to the first comb-shaped electrode 23. It becomes larger at the upper edge portions of −1 to 23-3 and the upper edge portions of the second comb-shaped electrodes 24-1 to 24-3.

  That is, if the high dielectric insulating layer 26 is formed in such a portion where the action of electrostatic force is large, the first comb-shaped electrode 11 and the second comb-shaped electrode 11 are caused by the spontaneous polarization of the insulating layer 26. The effect that the substantial distance with 13 is reduced can be obtained. Accordingly, as the substantial distance between the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3 is reduced, these electrodes, that is, the stator 29 and Even when the moving distance of the moving element 22 is somewhat increased, it is possible to suppress a reduction in electrostatic force acting between them, and to suppress a decrease in operating speed and efficiency as an actuator. Can do.

  Further, the voltage applied to the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3 constituting the stator 29 and the mover 22, that is, the drive voltage is increased. It is no longer necessary to meet the demands for energy conservation.

  On the other hand, when the gap between the stator 29 and the mover 22 is about 5 μm and the voltage applied between them is about 30 V, the first comb-shaped electrodes 23-1 to 23-3 are formed on the outer peripheral surface. Charges are accumulated in the insulating layer formed on the outer peripheral surface of the second comb-shaped electrodes 24-1 to 24-3 constituting the insulating layer and the movable element 22 formed. Therefore, when the insulating layer 26 is formed over the entire outer peripheral surface, a predetermined voltage is applied to the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3. In the case of applying to the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3, the electrical signals (positive and negative voltages) accompanying the applied voltage are applied to the first comb-shaped electrodes 23-1 to 24-3. In some cases, the actuator 22 does not sufficiently function, and the movable element 22 may not be driven with respect to the stator 29 in accordance with the electrical signal.

  However, in the present embodiment, the insulating layer 26 is applied only to the upper edge portions of the first comb-shaped electrodes 23-1 to 23-3 and the upper edge portions of the second comb-shaped electrodes 24-1 to 24-3. Since it is provided, the surface distance of the insulating layer 26 can be reduced, and charge retention is reduced. Therefore, the above-described problem of charging of the insulating layer 26 can be avoided, and the above-described effects (provided that the electrostatic force can be reduced and the operation speed and efficiency can be suppressed by increasing the distance) can be reduced. It can also be achieved.

  In addition, in order to show | play the effect in this embodiment more effectively, the height (width H4) of the 1st comb-tooth type electrode 23-1 to 23-3 is 1st comb-tooth type electrode 23-. It is preferable that the height H3 is 1 to 23-3 and the height H3 of the second comb-shaped electrodes 24-1 to 24-3 is 1 / 4H3 to 1 / 10H3. .

  FIG. 20 shows the distance (displacement) between the first comb-shaped electrode 23-1 and the second comb-shaped electrode 24-1 and the static electricity acting between these electrodes of the rotary stepping motor 70 in this embodiment. It is a graph which shows the relationship with force.

  The first comb-shaped electrode 23-1 and the second comb-shaped electrode 24-1 had a height of 10 μm and a width of 5 μm. The first comb-shaped electrode 23-1 and the second comb-shaped electrode 24-1 were made of silicon. Furthermore, the width H4 of the insulating layer 26 was 1.25 μm, and the thickness was 0.25 μm. The length of the protruding portion of the insulating layer 26 was 0.25 μm.

  As shown in FIG. 20, when the insulating layer 26 is not formed, the first comb-shaped electrode 23-1 (stator 21) and the second comb-shaped electrode 24-1 ( Although the electrostatic force acting on the movable element 22) is small, it can be seen that the electrostatic force is increased by forming the insulating layer 26 on the entire surface of the electrode. Further, when the insulating layer 26 is formed on the upper edge portion of the first comb-shaped electrode 23-1, when the insulating layer 26 is not protruded from the upper end, the insulating layer 26 is formed on the entire surface of the electrode. In comparison, although the electrostatic force acting between the two electrodes is reduced, when the insulating layer 26 is protruded from the upper end, both electrodes are compared with the case where the insulating layer 26 is formed on the entire surface of the electrode. The electrostatic force acting between them is increasing.

  Therefore, it can be seen that it is extremely effective to form the insulating layer 26 so as to protrude from the upper end of the first comb-shaped electrode 23-1, etc., as in this embodiment.

  FIG. 21 is a modification of the above embodiment, and FIG. 22 is a side view of the first comb-shaped electrode 23-1 and the second comb-shaped electrode 24-1 of the rotary stepping motor 70 shown in FIG. It is. In this modification, as shown in FIG. 22, the additional conductive film 72 is formed on both side surfaces of the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3. Is different from the embodiment shown in FIG. For the sake of clarity, the additional conductive film 72 is omitted in the drawing shown in FIG. In this case, charging of the insulating layer 16 at the upper edge portion of the recess 13B of the first comb-shaped electrode 13 can also be effectively removed. Therefore, the disadvantage caused by the above-described charging of the insulating layer 16 can be eliminated.

  As shown in FIGS. 23 and 24, when the additional conductive film 72 is formed as in this modification, almost no electric field leakage from the insulating layer 26 to the side surface is observed ( FIG. 24) shows that the leakage of the electric field from the insulating layer 26 is relatively large when the additional conductive film 72 is not formed (FIG. 23). Therefore, as shown in FIG. 24, by providing an additional conductive film 72, the first comb-shaped electrodes 23-1 to 23-3 and the second comb-shaped electrodes 24-1 to 24-3 are provided. It can be seen that the electrostatic force acting increases.

  Note that the additional conductive film 72 can be formed in the same manner as the conductive film 42.

  Note that the driving method and other features of the rotary stepping motor 70 of the present embodiment are the same as those of the rotary stepping motor 20 shown in FIGS.

(Eighth embodiment)
FIG. 25 is a partial cross-sectional view showing a schematic configuration of a parallel stepping motor in the present embodiment. That is, in FIG. 25, in order to clarify the features of the present embodiment, the stator 31 is in a side view, and the other components are in a sectional view.

  As shown in FIG. 25, the translational stepping motor 80 of the present embodiment is the first comb-tooth type constituting the stator 31 in the translational stepping motor 30 of the second embodiment shown in FIG. 8 except that the conductive film 82 is formed so as to be in contact with and along the boundary 81 between the electrodes 33-1 to 33-3 and the insulating layer 36. The same configuration is adopted.

  In general, the gap between the first comb-shaped electrodes 33-1 to 33-3 constituting the stator 31 and the second comb-shaped electrodes 34-1 to 34-3 constituting the movable element 32 is about 5 μm. When the voltage applied between them is about 30 V, the insulating layer 36 and the second comb-shaped electrode 34-1 formed on the outer peripheral surface of the first comb-shaped electrodes 33-1 to 33-3. Charges are accumulated in the insulating layer 36 formed on the outer peripheral surface of .about.34-3. Therefore, even when a predetermined voltage is applied to the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3, an electrical signal ( (Positive and negative voltage) does not sufficiently act on the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3, and according to the electrical signal. The mover 32 may not be driven with respect to the stator 31 in some cases.

  However, in the present embodiment, since the conductive film 82 is provided as described above, the charge charged in the insulating layer 36 of the first comb-shaped electrodes 33-1 to 33-3 passes through the conductive film 72. Thus, the first comb-shaped electrodes 33-1 to 33-3 can be released, and the accumulation of charges as described above, that is, charging can be prevented. As a result, even when a predetermined voltage is applied to the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3, an electric signal accompanying the applied voltage is obtained. (Positive and negative voltages) do not sufficiently act on the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3, and the electric signals In addition, it is possible to avoid the inconvenience that the movable element 22 is not driven with respect to the stator 29.

  In the present embodiment, the conductive film 82 is provided only on the first comb-shaped electrodes 33-1 to 33-3, but the conductive film is further formed on the second comb-shaped electrodes 34-1 to 34-3. By providing the above, the above-described effects can be further increased.

  The conductive film 82 can be formed in the same manner as the conductive film 42 in the fourth embodiment.

  The driving method and other features of the translation stepping motor 80 of this embodiment are the same as those of the translation stepping motor 30 shown in FIG.

(Ninth embodiment)
FIG. 26 is a diagram showing a schematic configuration of the parallel stepping motor in the present embodiment.

  As shown in FIG. 26, the translational stepping motor 90 of the present embodiment is the first comb-teeth type constituting the stator 31 in the translational stepping motor 90 of the third embodiment shown in FIG. Instead of forming the insulating layer 36 so as to cover the outer peripheral surfaces of the electrodes 33-1 to 33-3, only the upper edge portion (of the convex portion) of the first comb-shaped electrodes 33-1 to 33-3 Instead of forming the insulating layer 36 so as to cover the outer peripheral surfaces of the second comb-shaped electrodes 34-1 to 34-3 constituting the moving element 32, the second comb teeth are provided. The insulating layer 36 is provided only on the upper edge portion of the (convex portion) of the mold electrodes 34-1 to 34-3.

  Although not specifically shown in the figure, these insulating layers 36 are formed over the entire depth direction perpendicular to the paper surface of the first comb-shaped electrodes 33-1 to 33-3. In addition, the second comb-shaped electrodes 34-1 to 34-3 are formed over the entire depth direction perpendicular to the paper surface. Further, the front end portion of the insulating layer 36 is not necessarily required to be at the same plane level as the top surface of the first comb-shaped electrodes 33-1 to 33-3 or the like. As long as the tip of the insulating layer 36 provided on 33-3 does not contact the tip of the insulating layer 36 provided on the second comb-shaped electrodes 34-1 to 34-3, even if it protrudes from the upper surface described above. Good. The protruding amount of the insulating layer 36 is in the range of 1/10 to 1/2 of the gap between the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3. It can be.

  In the present embodiment, the electrostatic force acting between the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3 is the first comb-shaped electrode 33. It becomes large in the upper end edge part of -1 to 33-3 and the upper end edge part of the 2nd comb-tooth type electrode 34-1 to 34-3.

  That is, if the high dielectric insulating layer 36 is formed in such a portion where the action of electrostatic force is large, the first comb-shaped electrodes 33-1 to 33-3 and the first comb are formed by the spontaneous polarization of the insulating layer 36. The effect that the substantial distance with the 2 comb-shaped electrodes 34-1 to 34-3 is reduced can be obtained. Therefore, as the substantial distance between the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3 is reduced, these electrodes, that is, the stator 31 and Even when the moving distance of the moving element 32 is somewhat increased, it is possible to suppress a reduction in electrostatic force acting between them, and to suppress a decrease in operating speed and efficiency as an actuator. Can do.

  Further, the voltage applied to the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3 constituting the stator 31 and the mover 32, that is, the drive voltage is increased. It is no longer necessary to meet the demands for energy conservation.

  On the other hand, when the gap between the stator 31 and the mover 32 is about 5 μm and the voltage applied between them is about 30 V, the first comb-shaped electrodes 33-1 to 33-3 are formed on the outer peripheral surface. Charges are accumulated in the insulating layer formed on the outer peripheral surface of the second comb-shaped electrodes 34-1 to 34-3 constituting the insulating layer and the movable element 32. Therefore, when the insulating layer 36 is formed over the entire outer peripheral surface, a predetermined voltage is applied to the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3. In the case of applying to the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3, the electric signals (positive and negative voltages) accompanying the applied voltage are applied to the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3. In some cases, the movable element 32 may not be sufficiently driven and the movable element 32 may not be driven with respect to the stator 31 in accordance with the electric signal.

  However, in the present embodiment, the insulating layer 36 is applied only to the upper edge portions of the first comb-shaped electrodes 33-1 to 33-3 and the upper edge portions of the second comb-shaped electrodes 34-1 to 34-3. Since it is provided, the surface distance of the insulating layer 36 can be reduced, and charge retention is reduced. Therefore, the above-described problem of charging of the insulating layer 36 can be avoided, and the above-described effects (provided that the electrostatic force can be reduced and the operation speed and efficiency can be suppressed by increasing the distance) can be reduced. It can also be achieved.

  Note that the height of the insulating layer 36 to be formed on the first comb-shaped electrodes 33-1 to 33-3 and the like can be set similarly to the height of the insulating layer 26 in the seventh embodiment.

  Also in the present embodiment, as shown in FIG. 18 of the seventh embodiment, the first comb-shaped electrodes 33-1 to 33-3 and the second of the stepping motor 90 for translation shown in FIG. An additional conductive film can be provided on both side surfaces of the comb-shaped electrodes 34-1 to 34-3. In this case, charging of the insulating layer 36 formed on the upper edge portions of the first comb-shaped electrodes 33-1 to 33-3 and the like can be more effectively prevented. Electric field leakage from the insulating layer 36 can be suppressed, and electrostatic force acting between the first comb-shaped electrodes 33-1 to 33-3 and the second comb-shaped electrodes 34-1 to 34-3. It can be seen that increases.

  The driving method and other features of the translational stepping motor 90 of this embodiment are the same as those of the translational stepping motor 30 shown in FIG.

(Tenth embodiment)
In this embodiment, the case where the electrostatic actuator as shown in each of the above embodiments is configured as a MEMS will be described.

  First, a predetermined conductor substrate is prepared, and the surface thereof is cleaned, and then, by photolithography, through a mask pattern having a pattern corresponding to the pattern of the first comb-shaped electrode and the second comb-shaped electrode. Then, the pattern of the first comb-shaped electrode and the second comb-shaped electrode is transferred to the photosensitive film by exposing and developing the photosensitive film (photoresist) added on the substrate. Then, the first comb-shaped electrode and the second comb are etched by etching the substrate using an etching solution, reactive gas, plasma, or the like through the mask formed of the photosensitive film formed by transfer. A dental electrode is obtained.

  Next, for the first comb-shaped electrode and the second comb-shaped electrode, a chemical vapor deposition (CVD) method, metal organic chemical vapor deposition (MOCVD) using the high dielectric material described above as a raw material. The insulating layer described above is formed on the outer peripheral surfaces of these electrodes by applying a chemical vapor deposition (ALV) method or an atomic layer deposition (ALD) method. When an insulating layer is formed only on one of the first comb-shaped electrode and the second comb-shaped electrode, the above-described CVD method or ALD method is applied only to the comb-shaped electrode on which this insulating layer is to be formed. Apply.

  According to the manufacturing process as described above, the first comb-shaped electrode and the second comb-shaped electrode can be changed from the μm order to the sub-μm order.

  Other members can also be formed by the micromachine technique as described above.

  When configuring a rotary stepping motor as shown in the second embodiment or a stepping motor for parallel movement as shown in the third embodiment, for example, by performing the above-described operation, One comb-shaped electrode and a second comb-shaped electrode are formed together with the stator and the mover, respectively.

  When the electrostatic actuator of the present invention is configured as a MEMS, the following configuration requirements are provided.

  The drive voltage can be operated at a relatively low voltage, specifically, it is driven at several volts to 150 V, and particularly, operation at a low voltage of 70 V or less, further 50 V or less can be performed with high accuracy.

  The shape and dimensions of the first electrode are configured such that the height, width, thickness, taper, and pitch are each 1 μm to 100 μm. The shape and dimensions of the second electrode are configured such that the height, width, thickness, taper, and pitch are 1 μm to 100 μm each.

  The insulating layer has a thickness of 0.1 μm to 5 μm. The dielectric constant of the insulating layer is required to be 300 or more.

  The gap (distance) between the electrodes is 0.1 μm to 10 μm.

  The electrostatic force is comprised between 0.1 μN and 500 μN per set.

  The above-described configuration is determined by the process constraints due to MEMS and the required functions such as fineness, high accuracy, and low voltage.

  Since the dielectric constant is 300 or more and the presence of an insulating layer having a thickness of 0.1 to 5 μm, it is possible to avoid applying a high voltage of 50 V to 70 V or more. Therefore, it is applied to the case of a MEMS comb actuator. It can be adapted to low voltage, high definition operation.

  In the MEMS comb actuator of the present invention, usually, a gap distance of about 1 μm to 2 μm is required to ensure insulation. On the other hand, when the gap distance is increased, the driving voltage must be increased. However, in the case of the present invention, there is an effect of artificially reducing the gap distance without sacrificing insulation, and the driving voltage also decreases. It is valid.

  In addition, when the load is very light, the thickness of the actuator can be reduced, so that the accuracy of deep reactive ion etching (DRIE) is improved and the gap distance can be reduced to about 0.5 μm. For example, when the head slider of a hard disk drive is very light and the overall shape is miniaturized, the minimum gap distance is considered to be 0.1 micron. It can be adapted.

  When the electrostatic force doubles the gap distance, the electrostatic force is reduced by half, so it is important to reduce the gap distance. However, since the actuator moves, the gap distance cannot be reduced in order to ensure insulation. However, in the MEMS comb-tooth actuator of the present invention, the electrostatic force can be increased by a factor of about 2 by forming a high dielectric constant film of 1 μm on both electrodes even with the same gap distance.

  In the MEMS comb actuator of the present invention, the etching by DRIE is tapered, resulting in a dimensional error of about 0.1 μm to 0.5 μm, and the distance between the stator and the mover is slightly increased. Even in this case, the electrostatic force is stabilized by the presence of the insulating layer.

The present invention has been described in detail based on the above specific examples. However, the present invention is not limited to the above specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Comb-shaped actuator 11 Stator 12 Mover 13 First comb-shaped electrode 14 Second comb-shaped electrode 16 Insulating layer 18 Spring member 19 AC power supply 20 Rotary stepping motor 21 Fixed end 22 Mover 23-1 23-3 First comb-shaped electrode 24-1 to 24-3 Second comb-shaped electrode 25 Interconnect member 26 Insulating layer 28-1 A pair of plate-shaped first spring members 28-2 A pair of plate-shaped The second spring member 28-3 A pair of plate-like third spring members 28-4 A pair of plate-like fourth spring members 29 Stator 30 Stepping motor 31 for parallel movement 31 Stator 32 Mover 33- 1-33-3 First comb-shaped electrode 34-1 to 34-3 Second comb-shaped electrode 36 Insulating layer 38 Spring member 42, 62, 82 Conductive film 52, 72 Additional conductive film

Claims (13)

A stator having a plurality of first comb-shaped electrodes, and a mover having a plurality of second comb-shaped electrodes,
The convex portions and the concave portions of the plurality of first comb-shaped electrodes of the stator and the convex portions and the concave portions of the plurality of second comb-shaped electrodes of the movable member are each formed such that the center portion thereof is an electrode. Arranged opposite to each other at a predetermined pitch along the arrangement direction,
At least one outer peripheral surface of the plurality of first comb-shaped electrodes and the plurality of second comb-shaped electrodes; and / or the plurality of first comb-shaped electrodes. An electrostatic actuator, wherein an insulating layer made of a high dielectric material having a relative dielectric constant of 300 or more is formed on the outer peripheral surface of the recess.   The insulating layer includes at least one outer peripheral surface of the convex portions of the plurality of first comb-shaped electrodes and the convex portions of the plurality of second comb-shaped electrodes, and / or the plurality of first first electrodes. The electrostatic actuator according to claim 1, wherein the electrostatic actuator is formed so as to cover an outer peripheral surface of the concave portion of the comb-shaped electrode.   The outer peripheral surfaces of the convex portions of the plurality of first comb-shaped electrodes and the convex portions of the plurality of second comb-shaped electrodes are covered with the insulating layer made of the high dielectric material. The electrostatic actuator according to claim 2, wherein the electrostatic actuator is characterized.   At least one of the plurality of first comb-shaped electrodes and the plurality of second comb-shaped electrodes has a side surface of the convex portion on which the insulating layer made of the high dielectric material is directed downward from above. 4. The electrostatic actuator according to claim 2, wherein the electrostatic actuator is formed in a taper shape and has a maximum thickness that is half or less of the pitch.   The insulating layer, at least one outer peripheral surface of the plurality of first comb-shaped electrodes and the plurality of second comb-shaped electrodes, and / or the plurality of first comb-shaped electrodes. 5. The conductive film according to claim 2, wherein the conductive film is formed along the entire boundary while being in contact with the boundary between the comb-shaped electrode and the outer peripheral surface of the concave portion. Electrostatic actuator.   The insulating layer includes at least a tip edge portion on an outer peripheral surface of the convex portion of the plurality of first comb-shaped electrodes and a tip edge portion on an outer peripheral surface of the convex portion of the plurality of second comb-shaped electrodes. 2. The electrostatic actuator according to claim 1, wherein the electrostatic actuator is formed at an upper edge portion on an outer peripheral surface of the recess of the plurality of first comb-shaped electrodes.   The insulating layer is formed on a leading edge portion on the outer peripheral surface of the convex portion of the plurality of first comb-shaped electrodes and on a leading edge portion on the outer peripheral surface of the convex portion of the plurality of second comb-shaped electrodes. The electrostatic actuator according to claim 6, wherein the electrostatic actuator is provided.   At least a leading edge portion on the outer peripheral surface of the convex portion of the plurality of first comb-shaped electrodes and a leading edge portion on the outer peripheral surface of the convex portion of the plurality of second comb-shaped electrodes. On the other hand, and / or an additional conductive film is formed on any surface of the insulating layer so as to be in contact with the boundary with the upper edge portion of the outer peripheral surface of the recess of the plurality of first comb-shaped electrodes. The electrostatic actuator according to claim 6 or 7, wherein the electrostatic actuator is formed.   The convex portions of the plurality of second comb-shaped electrodes of the mover are respectively positioned at the center portions of the concave portions of the plurality of first comb-shaped electrodes of the stator, and the electrostatic actuator is The electrostatic actuator according to any one of claims 1 to 8, wherein a comb-shaped actuator is configured.   The plurality of first comb-shaped electrodes constituting the stator and the plurality of second comb-shaped electrodes constituting the moving element are arranged concentrically, and the electrostatic actuator is a rotary stepping motor. The electrostatic actuator according to claim 1, wherein the electrostatic actuator is configured.   The plurality of first comb-shaped electrodes constituting the stator and the plurality of second comb-shaped electrodes constituting the movable element are arranged in parallel, and the electrostatic actuator is a stepping for parallel movement. The electrostatic actuator according to claim 1, comprising a motor.   The electrostatic actuator according to claim 1, wherein the high dielectric is an inorganic high dielectric.   The plurality of first comb-shaped electrodes constituting the stator and the plurality of second comb-shaped electrodes constituting the movable element are processed by micromachine technology, and the electrostatic actuator is The electrostatic actuator according to claim 1, wherein the electrostatic actuator is a MEMS electrostatic actuator.

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