JP5949927B2 - Electrostrictive actuator and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electrostrictive actuator and a manufacturing method thereof, and particularly to an electrostrictive actuator using an electrostrictive resin sheet made of a polymer electrostrictive material and a manufacturing method thereof.

  An electrostrictive actuator that is of interest to the present invention is described in, for example, Japanese Patent Application Laid-Open No. 2009-232523 (Patent Document 1). Patent Document 1 describes an actuator in which a dielectric elastomer as a polymer electrostrictive material and an electrode are laminated. In this prior art, when a voltage is applied to the dielectric elastomer via an electrode, the dielectric elastomer is deformed. In order to greatly deform the dielectric elastomer, a soft elastomer having an elastic modulus of 1 MPa or less is used.

  On the other hand, the electrode is formed by using a paste or a paint in which conductive carbon such as carbon black or carbon nanotube is mixed with oil or elastomer as a binder. Here, since carbon black and carbon nanotubes are relatively hard particles, hard particles such as carbon black and carbon nanotubes harden the electrode. Therefore, in order to keep the electrode soft, it is preferable not to contain a lot of hard particles such as carbon black and carbon nanotubes. However, in order to obtain the necessary conductivity in the electrode, the conductivity such as carbon black and carbon nanotubes is required. It is necessary to contain a relatively large amount of the conductive particles, for example, 10% by volume or more.

  As a result, the electrode becomes stiff and therefore encounters the problem that deformation of the dielectric elastomer is impeded.

  Note that it is conceivable to reduce the influence of deformation inhibition by the electrode by sufficiently increasing the thickness of the dielectric elastomer as compared with the thickness of the electrode. However, in this case, another problem is encountered in that the voltage to be applied to deform the dielectric elastomer must be increased with the increase in thickness of the dielectric elastomer. For example, when the thickness of the dielectric elastomer is increased to 100 μm with respect to the thickness of the electrode 10 μm, the influence of deformation inhibition by the electrode is usually reduced per 1 μm of the dielectric elastomer thickness. Since a voltage of about 150 V is applied, when the dielectric elastomer has a thickness of 100 μm, a high voltage of about 15 kV must be applied.

JP 2009-232523 A

  Accordingly, an object of the present invention is to provide an electrostrictive actuator that can reduce the problem of inhibiting deformation of an electrostrictive resin sheet by an electrode as described above, and a manufacturing method thereof.

The present invention provides an electrostrictive resin sheet made of a polymer electrostrictive material and a first electrode provided in contact with both main surfaces of the electrostrictive resin sheet in order to apply a voltage in the thickness direction of the electrostrictive resin sheet. In order to solve the above-described technical problem, the electrostrictive resin sheet is bonded to the electrostrictive resin sheet in a face-to-face state. The insulating resin sheet further includes an electrically insulating insulating resin sheet having a lower elastic modulus than the electrostrictive resin sheet, and the insulating resin sheet has a plurality of minute recesses having a lamellar structure directed from the main surface to the inside. And at least one of the first and second electrodes forms a current path extending in a main surface direction in a surface layer of the insulating resin sheet extending along the main surface in contact with the electrostrictive resin sheet. Do And than, is characterized in that is provided by an organic conductive ink infiltrated into the recess toward the inside from the main surface of the insulating resin sheet.

  According to the electrostrictive actuator having the above structure, the insulating resin sheet has a lower elastic modulus than the electrostrictive resin sheet, that is, more easily deformed such as bending and stretching. It does not substantially inhibit the deformation. In addition, since at least one of the first and second electrodes is provided by a conductive material distributed in the surface layer of the insulating resin sheet that is likely to be deformed such as bending and stretching, at least one of the first and second electrodes No substantial deformation of the electrostrictive resin sheet such as bending or elongation is hindered.

  The present invention is also directed to a method of manufacturing an electrostrictive actuator having the above-described structure.

An electrostrictive actuator manufacturing method according to the present invention includes a step of preparing an electrostrictive resin sheet made of a polymer electrostrictive material, and a lamellar structure having a lower elastic modulus than the electrostrictive resin sheet and extending from the main surface toward the inside. a plurality of fine recesses by is formed, the steps of preparing an electrically insulating property of the insulating resin sheet, by infiltrating the organic conductive ink to the recess toward the inside from the main surface of the insulating resin sheet, insulation Forming an electrode for forming a current path extending in the direction of the main surface in the surface layer extending along at least one main surface of the conductive resin sheet, so that the electrode contacts at least one main surface of the electrostrictive resin sheet And a step of joining the insulating resin sheet and the electrostrictive resin sheet in a face-to-face state.

  In this invention, it is preferable that the electrostrictive resin sheet and the insulating resin sheet have a common main component. This is because, when joining the electrostrictive resin sheet and the insulating resin sheet, good adhesion can be obtained between them.

  In the above-mentioned case, as the electrostrictive resin sheet, if the sheet obtained by stretching a sheet made of the same material as the insulating resin sheet is used, the cost can be reduced by sharing the material, and stretching As a result of the improvement of the elastic modulus, the elastic modulus of the insulating resin sheet before stretching can be surely made lower than the elastic modulus of the electrostrictive resin sheet after stretching.

  As the electrostrictive resin sheet described above, a uniaxially stretched sheet is preferably used. In this case, a plurality of wrinkles extending in the stretching direction are usually formed on the surface of the electrostrictive resin sheet. On the other hand, since the insulating sheet has a lower elastic modulus than the electrostrictive sheet, the insulating sheet follows the surface of the electrostrictive resin sheet so as not to form a gap between the insulating sheet and the electrostrictive resin sheet. Will have a rough surface. According to such a structure, the problem resulting from the space | gap between an electrostrictive resin sheet and an insulating resin sheet can be avoided. That is, in the case where an air layer is present between the electrodes in addition to the electrostrictive resin sheet, the electrical characteristics such as the apparent dielectric constant between the electrodes are greatly reduced. According to this, such a problem can be avoided.

  When manufacturing an electrostrictive actuator having the above-described configuration, the step of joining the insulating resin sheet and the electrostrictive resin sheet in a face-to-face state is performed so that the surface of the electrostrictive resin sheet follows the insulating resin. It is preferable that the insulating resin sheet and the electrostrictive resin sheet be thermocompression-bonded while the sheet is deformed.

In order to form the electrode, in the present invention, as described above, the organic conductive ink is infiltrated into the concave portion having a lamellar structure directed from the main surface of the insulating resin sheet toward the inside. In general, fine irregularities due to a lamellar structure are formed on the surface of a polymer film. Since the insulating resin sheet used in the present invention is also a polymer film, the main surface has fine unevenness due to such a lamellar structure, that is, a plurality of fine recesses due to the lamellar structure from the main surface to the inside. Is formed. Therefore, when the organic conductive ink is infiltrated into the main surface of the insulating resin sheet, the conductive material using the organic conductive ink is advantageous in a state where a current path extending in the main surface direction is formed in the surface layer of the insulating resin sheet. Can be distributed. Further, the electrode formed in this way is easily deformed following the bending deformation of the insulating resin sheet. Therefore, the electrode is not easily broken by the bending deformation, thereby improving the reliability of electrical conduction in the electrode. be able to.

  In the present invention, typically, as the insulating resin sheet, a first insulating resin sheet that holds the first electrode and a second insulating resin sheet that holds the second electrode are prepared. The strain resin sheet is sandwiched between the first insulating resin sheet and the second insulating resin sheet.

  Moreover, in this invention, it is preferable that the electrostrictive resin sheet and the insulating resin sheet are in a wound state. In this case, by increasing the number of windings, the number of layers of the electrostrictive resin sheets can be increased, and a stronger displacement force can be obtained in the electrostrictive actuator.

  According to the electrostrictive actuator according to the present invention, since the insulating resin sheet and the electrode are more easily bent and deformed than the electrostrictive resin sheet, the insulating resin sheet and the electrode substantially deform the electrostrictive resin sheet. Will not be disturbed. Therefore, a highly efficient electrostrictive actuator can be obtained.

  According to the electrostrictive actuator manufacturing method of the present invention, at least one of the electrodes is not directly formed on the electrostrictive resin sheet, but is formed on the insulating resin sheet, and then the electrode is electrostrictive resin sheet. The insulating resin sheet and the electrostrictive resin sheet are joined in a face-to-face state so as to be in contact with at least one of the main surfaces. Therefore, the problem of electrical short-circuiting of electrodes between the front and back main surfaces that can occur when electrodes are formed on both main surfaces of an extremely thin electrostrictive resin sheet having a thickness of, for example, 1 μm using, for example, organic conductive ink. Can be advantageously avoided.

The manufacturing method of the electrostrictive actuator 1 by this 1st Embodiment is shown in order of a process, (1) is the electrostrictive resin sheet 2 and the insulating resin sheets 3 and 4 which comprise the electrostrictive actuator 1, FIG. 2 is a cross-sectional view separately showing each other, and FIG. 2B is a cross-sectional view showing a state where the electrostrictive resin sheet 2 and the insulating resin sheets 3 and 4 shown in FIG. Yes, (3) is a state where the electrostrictive resin sheet 2 and the insulating resin sheets 3 and 4 shown in (2) are wound and the terminal conductors 14 and 15 are formed, that is, a completed electrostrictive actuator. 1 is a perspective view showing 1. FIG. It is sectional drawing which shows typically the state which formed the electrode 9 in the surface layer 7 extended along the main surface 5 of the insulating resin sheet 3 shown to FIG. 1 (1). It is a top view which expands and schematically shows a part of main surface 5 of the insulating resin sheet 3 shown in FIG. A preferred embodiment adopted to increase the reliability of the electrical connection between the terminal conductors 14 and 15 shown in FIG. 1 (3) and the electrodes 9 and 10 shown in FIGS. 1 (1) and (2) will be described. It is a perspective view of the sheet laminated body 20 for doing. 1 is a schematic cross-sectional view for explaining a laminated state of an electrostrictive resin sheet 2 and insulating resin sheets 3 and 4 in the embodiment shown in FIG. 1, (A) is a state before lamination, (B ) Shows the state after lamination. It is a figure corresponding to FIG. 5 for demonstrating the 2nd Embodiment of this invention. It is a figure corresponding to FIG. 5 for demonstrating the 3rd Embodiment of this invention. It is a figure corresponding to FIG. 5 for demonstrating the 4th Embodiment of this invention. It is a perspective view which shows the external appearance of the braille display apparatus 31 as a preferable application example of the electrostrictive actuator which concerns on this invention.

  With reference to FIG. 1 thru | or FIG. 3, the manufacturing method of the electrostrictive actuator 1 by one Embodiment of this invention is demonstrated first. This is because if the manufacturing method of the electrostrictive actuator 1 is understood, the structure of the electrostrictive actuator 1 becomes clear.

  As shown in FIG. 1 (1), an electrostrictive resin sheet 2 and first and second insulating resin sheets 3 and 4 are prepared.

  The electrostrictive resin sheet 2 is made of a polymer electrostrictive material. The polymer electrostrictive material is not particularly limited as long as it is a polymer material having a permanent dipole. Examples of the polymer electrostrictive material include PVDF (polyvinylidene fluoride), a PVDF copolymer, for example, a copolymer such as P (VDF-TrFE) and P (VDF-VF), and P (VDF-TrFE). -CFE), P (VDF-TrFE-CTFE), P (VDF-TrFE-CDFE), P (VDF-TrFE-HFA), P (VDF-TrFE-HFP), P (VDF-TrFE-VC), etc. A terpolymer may be mentioned. Among these, P (VDF-TrFE-CFE) is particularly preferable in that a large distortion can be obtained.

  In the above example of the polymer electrostrictive material, P is poly, VDF is vinylidene fluoride, TrFE is trifluoroethylene, CFE is chlorofluoroethylene, CTFE is chlorotrifluoroethylene, and CDFE is chloro. Difluoroethylene, HFA represents hexafluoroacetone, HFP represents hexafluoropropylene, VC represents vinyl chloride, and VF represents vinyl fluoride.

  The thickness of the electrostrictive resin sheet 2 may be set as appropriate, but may be, for example, about several μm to 100 μm.

  The insulating resin sheets 3 and 4 may be made of a polymer electrostrictive material as in the case of the electrostrictive resin sheet 2 or may be made of another polymer material that does not have electrostrictive properties. . On the other hand, the insulating resin sheets 3 and 4 must satisfy the condition that the elastic modulus is lower than that of the electrostrictive resin sheet 2, that is, bendable more easily. Therefore, preferably, as the insulating resin sheets 3 and 4, the above-described polymer electrostrictive material is used without stretching, and the electrostrictive resin sheet 2 is made of the same material as the insulating resin sheets 3 and 4. The resulting sheet is drawn and fibrillated.

  In general, the organic material can be stretched at a temperature not lower than the glass transition point and not higher than the melting point. For example, in the case of an organic material having a glass transition point of 0 ° C. or lower and a melting point of 120 ° C., it can be stretched at room temperature, but it is desirable to stretch at a temperature of 40-50 ° C. In stretching, both ends of the sheet are held, and in that state, the sheet is stretched by pulling to a length of 2 times or more, preferably 3 times or more of the initial length. Even when batch processing for pulling the sheets one by one is adopted, a roll-to-roll method in which the number of rotations of the roll on the winding side is made larger than the number of rotations of the roll on the supply side may be adopted. The pulling speed is selected to be, for example, 10 mm / second or more.

  If the initial sheet made of the same material as the insulating resin sheets 3 and 4 is stretched, the electrostrictive resin sheet 2 having an elastic modulus higher than that of the initial sheet is obtained. For example, when the elastic modulus of the initial sheet is 100 MPa, if this is stretched 4 times, the elastic modulus increases to 400 MPa.

  Next, in the surface layers 7 and 8 extending along the main surfaces 5 and 6 of the first and second insulating resin sheets 3 and 4, respectively, the conductive layer is formed in a state in which a current path extending in the main surface direction is formed. First and second electrodes 9 and 10 in which materials are distributed are formed, respectively. This process will be described with reference to FIGS. 2 and 3 when the electrode 9 is formed on one insulating resin sheet 3.

  An organic conductive ink is used to form the electrode 9. The organic conductive ink is obtained by, for example, dissolving an organic conductive material such as PEDOT (polyethylenedioxythiophene), PPy (polypyrrole), PANI (polyaniline) in an organic solvent.

As described above, generally, fine unevenness due to a lamellar structure is formed on the surface of a polymer film. FIG. 3 schematically shows an enlarged part of the main surface 5 of the insulating resin sheet 3. As shown in FIG. 3, the main surface 5 of the insulating resin sheet 3 has a crystal part called a lamella 11, and the fine unevenness due to such a lamella structure, that is, the lamella structure that goes from the main surface to the inside. A plurality of fine recesses are formed.

  Therefore, when the organic conductive ink described above is applied to the main surface 5 of the insulating resin sheet 3 by a method such as brush coating, silk screen printing, spray pattern coating, or the like, as shown in FIG. On the surface layer 7 of the insulating resin sheet 3, an electrode 9 is formed in which a conductive material made of organic conductive ink is distributed in a state in which a current path extending in the main surface direction is formed. FIG. 3 schematically shows the conductive material 12 taken into a minute recess having a lamellar structure. The organic conductive ink is heat-treated at 85 ° C. for 30 minutes, for example, after application.

  Since the electrode 9 formed in this manner exists only in the surface layer 7 of the insulating resin sheet 3, the electrode 9 easily bends and follows the bending deformation of the insulating resin sheet 3, and functions as an extensible electrode. Therefore, it is difficult to be destroyed by bending deformation. Further, as shown in FIG. 3, the conductive material 12 taken into the minute recesses having the lamella structure forms a number of current paths corresponding to the number of the minute recesses having the lamella structure. For these reasons, the electrode 9 can obtain an electrically conductive state having high reliability.

  As illustrated before, in order to form the electrode 9 on the main surface 5 of the insulating resin sheet 3 having an elastic modulus of 100 MPa, the organic conductive ink containing the aforementioned PEDOT is used as the insulating resin. An experiment was performed in which the sheet 3 was adhered to the lamella structure portion of the main surface 5 with a thickness of 10 to 400 nm. In this case, although the elastic modulus of PEDOT is 2 GPa, the elastic modulus of the portion where the electrode 9 is formed in the insulating resin sheet 3 is higher than 100 MPa which is the elastic modulus of the insulating resin sheet 3, and the insulating resin sheet 3 was confirmed to be lower than 400 MPa, which is the elastic modulus of the electrostrictive resin sheet 2 obtained by stretching the initial sheet made of the same material as 3 by 4 times.

  The above description with reference to FIGS. 2 and 3 also applies to the case where the second electrode 10 is formed on the second insulating resin sheet 4.

  The electrostrictive resin sheet 2 and the insulating resin sheets 3 and 4 shown in FIG. 1 (1) have a longitudinal shape extending in a direction orthogonal to the paper surface. In FIG. Cross sections in the width direction of the resin sheet 2 and the insulating resin sheets 3 and 4 appear.

  As shown in FIG. 1 (1), the first electrode 9 formed on the first insulating resin sheet 3 is formed so as to reach the left end of the first insulating resin sheet 3 as shown in FIG. A predetermined gap is formed on the right end of the insulating resin sheet 3 of FIG. On the other hand, the second electrode 10 formed on the second insulating resin sheet 4 is formed so as to reach the right end of the second insulating resin sheet 4 according to the drawing, and the second insulating resin sheet 4 A predetermined gap is formed at the left end in the figure.

  Next, as shown in FIG. 1 (2), the first and second insulating resins are such that the first and second electrodes 9 and 10 are in contact with both main surfaces of the electrostrictive resin sheet 2, respectively. Sheets 3 and 4 and electrostrictive resin sheet 2 are joined in a face-to-face state. More specifically, after the first and second insulating resin sheets 3 and 4 and the electrostrictive resin sheet 2 are stacked, for example, a state where the vacuum is applied while applying heat of 85 to 100 ° C. The first and second insulating resin sheets 3 and 4 and the electrostrictive resin sheet 2 are bonded together by thermocompression bonding. Instead of thermocompression bonding, bonding with an adhesive from an epoxy resin or the like may be applied.

  Next, the three-layered sheet laminate 20 in which the first and second insulating resin sheets 3 and 4 and the electrostrictive resin sheet 2 are bonded is an axis line in the left-right direction in FIG. Thus, a roll-shaped actuator main body 13 as shown in FIG. 1 (3) is obtained. In FIGS. 1 (1) and (2), the electrostrictive resin sheet 2 and the first and second insulating resin sheets 3 and 4 are illustrated with exaggerated thickness direction dimensions. Please point out.

  Next, first and second terminal conductors 14 and 15 are formed at both ends of the actuator body 13, respectively. Terminal conductors 14 and 15 are formed, for example, by applying a silver paste. In the roll-shaped actuator body 13, the first electrode 9 is exposed at the left end face according to FIG. 1 (3), so that the first terminal conductor 14 is electrically connected to the first electrode 9. On the other hand, since the second electrode 10 is exposed at the right end face, the second terminal conductor 15 is electrically connected to the second electrode 10.

  The electrostrictive actuator 1 is obtained as described above.

  In the state shown in FIG. 1 (2), the main surfaces facing the outside of each of the first and second insulating resin sheets 3 and 4 are electrically insulating, so as shown in FIG. Even when the insulating resin sheets 3 and 4 and the electrostrictive resin sheet 2 are wound, no leakage current is generated between the electrodes 9 and 10.

  In the electrostrictive actuator 1, when a voltage is applied between the first and second electrodes 9 and 10 via the first and second terminal conductors 14 and 15, electrostriction deformation is caused thereby. The thickness of the electrostrictive resin sheet 2 between the first and second electrodes 9 and 10 decreases. As a result, the electrostrictive resin sheet 2 extends in the surface direction, and the actuator body 13 is displaced so as to extend in the axial direction as indicated by a double arrow 16 in FIG. This amount of displacement can be controlled by the applied voltage. On the other hand, if the voltage application is cut off, the actuator body 13 returns to the original state.

  By increasing the number of turns for obtaining the roll-shaped actuator body 13, the number of layers of the electrostrictive resin sheet 2 can be increased, and a stronger displacement force can be obtained in the electrostrictive actuator 1.

  As a modification of the embodiment described above, the configuration shown in FIG. 4 may be employed. In FIG. 4, the sheet laminate 20 is shown in a perspective view, but it should be pointed out that the thickness in the thickness direction of the sheet laminate 20 is considerably exaggerated.

  At the stage before winding the sheet laminate 20, as shown in FIG. 4, the edge 21 on the drawer side of the electrodes 9 and 10 (the electrode 10 is shown in FIG. 4) of the sheet laminate 20 is shown. A plurality of cuts 23 and 24 may be formed so as to be distributed along the lines 22 and 22. In this case, before winding the sheet laminate 20, the organic conductive ink flows along each of the edges 21 and 22 of the sheet laminate 20, more specifically, each end face and the main surface adjacent thereto. It is applied along each part. As this organic conductive ink, the same organic conductive ink as used for forming the electrodes 9 and 10 can be used. The organic conductive ink penetrates into the cuts 23 and 24 and is electrically connected to each of the electrodes 9 and 10.

  Therefore, according to the preferred embodiment described above, when the terminal conductors 14 and 15 are formed as shown in FIG. 1 (3) after the sheet laminate 20 is wound as indicated by the arrow 19, the terminal conductor 14 And 15 are surely in contact with the organic conductive ink soaked in each of the cuts 23 and 24, so that the reliability of the electrical connection between the terminal conductors 14 and 15 and the electrodes 9 and 10 can be improved.

  In the case of the preferred embodiment described above, the terminal conductors 14 and 15 formed by applying a silver paste, for example, by applying a terminal conductor by the organic conductive ink itself soaked in each of the cuts 23 and 24. May be omitted.

  FIG. 5 is a cross-sectional view for explaining a laminated state of the electrostrictive resin sheet 2 and the insulating resin sheets 3 and 4 in the embodiment shown in FIG. In FIG. 5, elements corresponding to the elements shown in FIG.

  As described above, a uniaxial stretching process is performed in order to obtain the electrostrictive resin sheet 2 having a relatively high elastic modulus. However, when uniaxially stretched, in the polymer electrostrictive material, polar groups are oriented or structural anisotropy is brought about to improve the electrostrictive characteristics. As a result, the electrostrictive resin sheet 2 is formed with fine wrinkles extending in the stretching direction. As a result, the surface of the electrostrictive resin sheet 2 is stretched in the stretching direction. A plurality of fine ridges extending in the direction are formed. In FIG. 5, these ridges 25 are very schematically illustrated by wavy lines.

  Since the electrostrictive resin sheet 2 has a high elastic modulus by stretching, the surface thereof is relatively hard. Therefore, if the electrostrictive resin sheet 2 having the ridges 25 formed on the surface is used instead of the insulating resin sheets 3 and 4 having a relatively low elastic modulus shown in FIG. In the laminated state shown in B), voids are generated between the sheets, and these voids tend to remain after thermocompression bonding. In addition, if the pressure bonding is performed at a temperature at which heat melting occurs, the voids may be eliminated, but in this case, the orientation is lost in the electrostrictive resin sheet 2 and the characteristics are deteriorated. .

  In this embodiment, since the insulating resin sheets 3 and 4 having a relatively low elastic modulus are laminated so as to be in contact with the electrostrictive resin sheet 2 having the flange 25 formed on the surface, the insulating resin sheets 3 and 4 are laminated. As shown in FIG. 5 (B), it easily deforms following the surface of the electrostrictive resin sheet 2 so as not to form a gap with the electrostrictive resin sheet 2. That is, the insulating resin sheets 3 and 4 have a surface that follows the surface of the electrostrictive resin sheet 2.

  In order to obtain the laminated structure as described above, the insulating resin sheets 3 and 4 and the electrostrictive resin sheet 2 are joined so as to follow the surface of the electrostrictive resin sheet 2 in the process of joining the electrostrictive resin sheets 2 in a face-to-face state. The insulating resin sheets 3 and 4 and the electrostrictive resin sheet 2 may be thermocompression bonded while the resin sheets 3 and 4 are deformed.

  According to the laminated structure shown in FIG. 5B, it is possible to avoid the problem of a decrease in apparent dielectric constant caused by the gap between the sheets 2-4. That is, when an air layer is present between the electrodes 9 and 10 in addition to the electrostrictive resin sheet 2, the apparent dielectric constant between the electrodes 9 and 10 is greatly reduced. According to the stacked structure shown in FIG. 5B, such a problem can be avoided.

  Introducing an experimental example carried out to confirm the problem due to the air layer, a laminate having a thickness of 3 μm and a planar dimension of 20 mm × 35 mm was obtained. When the relative dielectric constant was obtained, it was 11. However, when the stretched film and the unstretched film were superposed, the capacity was 62 nF, and when the relative dielectric constant was obtained, it was 30 and higher. It was.

  FIGS. 6 to 8 correspond to FIG. 5 and are for explaining second to fourth embodiments of the present invention, respectively. 6 to 8, elements corresponding to those shown in FIG. 5 are denoted by the same reference numerals.

  As described above, when the first and second insulating resin sheets 3 and 4 and the electrostrictive resin sheet 2 are wound, one of the first and second insulating resin sheets 3 and 4 is Omitted and the first and second electrodes corresponding to the first and second electrodes 9 and 10 may be formed on each main surface of the remaining insulating resin sheet, respectively. Even when such a configuration is adopted, when the insulating resin sheet and the electrostrictive resin sheet are wound, the first and second electrodes are in contact with both main surfaces of the electrostrictive resin sheet, respectively. Can be obtained.

  In FIG. 6A, as described above, the first insulating resin sheet 3 is omitted, and the first insulating resin sheet 3 is left on the surface layer extending along each main surface of the second insulating resin sheet 4. A second embodiment is shown in which a second electrode 9 and a second electrode 10 are respectively formed. Also in this embodiment, when the insulating resin sheet 4 having a relatively low elastic modulus is laminated so as to be in contact with the electrostrictive resin sheet 2 having the surface 25 formed on the surface, and the thermocompression bonding is performed, the insulating resin sheet 6 is easily deformed following the surface of the electrostrictive resin sheet 2 so as not to form a gap with the electrostrictive resin sheet 2 as shown in FIG.

  In FIG. 7A, the first insulating resin sheet 3 is omitted, and the second electrode 10 is formed on the surface layer extending along the lower main surface of the remaining second insulating resin sheet 4 as shown in the drawing. A third embodiment is shown in which the first electrode 9 is formed on the lower main surface of the electrostrictive resin sheet 2 as shown in the figure. Also in this embodiment, when the insulating resin sheet 4 having a relatively low elastic modulus is laminated so as to be in contact with the electrostrictive resin sheet 2 having the surface 25 formed on the surface, and the thermocompression bonding is performed, the insulating resin sheet 7 is easily deformed following the surface of the electrostrictive resin sheet 2 so as not to form a gap with the electrostrictive resin sheet 2 as shown in FIG.

  In FIG. 8A, the first insulating resin sheet 3 is omitted, and the first electrode 9 is formed on the surface layer extending along the upper main surface of the remaining second insulating resin sheet 4 in the drawing. In the fourth embodiment, the second electrode 10 is formed on the upper main surface of the electrostrictive resin sheet 2 as shown in the drawing. Also in this embodiment, when the insulating resin sheet 4 having a relatively low elastic modulus is laminated so as to be in contact with the electrostrictive resin sheet 2 having the surface 25 formed on the surface, and the thermocompression bonding is performed, the insulating resin sheet As shown in FIG. 8B, No. 4 easily deforms following the surface of the electrostrictive resin sheet 2 so as not to form a gap with the electrostrictive resin sheet 2.

  In the third and fourth embodiments shown in FIGS. 7 and 8, in the state before lamination, one of the first and second electrodes 9 and 10 is on the electrostrictive resin sheet 2 side. Is formed. Even in this case, the problem of inhibiting deformation of the electrostrictive resin sheet 2 can be reduced as compared with the case where electrodes are formed on both surfaces of the electrostrictive resin sheet 2.

  As described above, the roll-shaped electrostrictive actuator 1 as shown in FIG. 1 (3) is displaced as indicated by the double arrow 16. According to the electrostrictive actuator 1, it has been confirmed that, for example, a diameter of 1 mm, a displacement of 50 to 100 μm, and a generated force of 0.5 N can be obtained. Accordingly, for example, by arranging six electrostrictive actuators 1 vertically and two horizontally, and applying a voltage to each electrostrictive actuator 1, an apparatus for variably displaying Braille is advantageously provided. Can be configured.

  The electrostrictive actuator 1 can also be applied to the braille display device 31 shown in FIG. On the display surface 32 of the braille display device 31, as shown in an abbreviated manner in FIG. 9, a plurality of electrostrictive actuators 1 have their respective end surfaces (surfaces provided with the terminal conductors 14 or 15) directed in the same direction. Are arranged. As an example, the plurality of electrostrictive actuators 1 can be arranged at 1 mm intervals, and a display of 64 × 98 dots can be realized.

  Although the invention has been described with reference to the illustrated embodiment, various other embodiments are possible within the scope of the invention.

  For example, although the illustrated electrostrictive actuator 1 has a roll shape, the electrostrictive actuator may be configured while the structure illustrated in FIG. In this case, a plurality of the sheet laminates 20 shown in FIG. 1 (2) or FIG. 5 (B) may be laminated as necessary. Similarly, a plurality of the sheet laminates 20 shown in FIG. 6B, FIG. 7B, or FIG. 8B may be laminated. Moreover, when winding the sheet | seat laminated body 20, it can also be set as the wound body which has other cross-sectional shapes, such as an oval cross-section, instead of making it a roll shape with a circular cross section.

DESCRIPTION OF SYMBOLS 1 Electrostrictive actuator 2 Electrostrictive resin sheet 3, 4 Insulating resin sheet 5, 6 Main surface 7, 8 Surface layer 9, 10 Electrode 11 Lamella 12 Conductive material 13 Actuator body 14, 15 Terminal conductor

Claims (10)

An electrostrictive resin sheet made of a polymer electrostrictive material;
In order to apply a voltage in the thickness direction of the electrostrictive resin sheet, first and second electrodes provided to be in contact with both main surfaces of the electrostrictive resin sheet,
It is bonded to the electrostrictive resin sheet in a face-to-face state, and has an elastic modulus lower than that of the electrostrictive resin sheet, and an electrically insulating insulating resin sheet,
With
The insulating resin sheet is formed with a plurality of fine recesses by a lamellar structure from the main surface to the inside,
At least one of the first and second electrodes forms a current path extending in the main surface direction in a surface layer of the insulating resin sheet extending along the main surface in contact with the electrostrictive resin sheet. Yes, it is given by the organic conductive ink that has penetrated into the recess from the main surface of the insulating resin sheet toward the inside,
Electrostrictive actuator.   The electrostrictive resin sheet has a plurality of ridges formed on the surface thereof, and the insulating resin sheet is formed on the electrostrictive resin sheet so as not to form a gap between the electrostrictive resin sheet and the electrostrictive resin sheet. The electrostrictive actuator according to claim 1, wherein the electrostrictive actuator has a surface that follows the surface.   The electrostrictive actuator according to claim 1, wherein the electrostrictive resin sheet and the insulating resin sheet have main components common to each other. The insulating resin sheet includes a first insulating resin sheet that holds the first electrode and a second insulating resin sheet that holds the second electrode, and the electrostrictive resin sheet includes: The electrostrictive actuator according to any one of claims 1 to 3 , wherein the electrostrictive actuator is sandwiched between the first insulating resin sheet and the second insulating resin sheet. The electrostrictive resin sheet and said is in a state where the insulating resin sheet is wound, electrostriction actuator according to any one of claims 1 to 4. Preparing an electrostrictive resin sheet made of a polymer electrostrictive material;
Preparing an electrically insulating insulating resin sheet having a lower elastic modulus than the electrostrictive resin sheet and having a plurality of fine concave portions formed by a lamellar structure from the main surface to the inside; and
An electric current extending in the main surface direction in a surface layer extending along at least one main surface of the insulating resin sheet by infiltrating the organic conductive ink into the concave portion extending inward from the main surface of the insulating resin sheet. Forming an electrode for forming a path;
Bonding the insulating resin sheet and the electrostrictive resin sheet in a face-to-face state so that the electrode is in contact with at least one main surface of the electrostrictive resin sheet;
A method of manufacturing an electrostrictive actuator. The electrostrictive actuator according to claim 6 , wherein the step of preparing the electrostrictive resin sheet includes a step of obtaining the electrostrictive resin sheet by stretching a sheet made of the same material as the insulating resin sheet. Manufacturing method. The step of joining the insulating resin sheet and the electrostrictive resin sheet in a face-to-face state is performed by deforming the insulating resin sheet so as to follow the surface of the electrostrictive resin sheet. The manufacturing method of the electrostrictive actuator of Claim 6 or 7 including the process of thermocompression bonding with the said electrostrictive resin sheet. The step of preparing the insulating resin sheet includes a step of preparing a first insulating resin sheet that holds the first electrode and a second insulating resin sheet that holds the second electrode. ,
The step of joining the insulating resin sheet and the electrostrictive resin sheet includes a state in which the electrostrictive resin sheet is sandwiched between the first insulating resin sheet and the second insulating resin sheet. So as to comprise the step of joining each of the first and second insulating resin sheets and the electrostrictive resin sheet,
Method for producing electrostrictive actuator according to any one of claims 6 to 8. After the step of bonding the electrostrictive resin sheet and the insulating resin sheet, further comprising the step of winding said electrostrictive resin sheet and the insulating resin sheet, in any one of claims 6 to 9 The manufacturing method of the electrostrictive actuator of description.

Images