WO2015093356A1 - Method for manufacturing piezoelectric sensor - Google Patents

Method for manufacturing piezoelectric sensor Download PDF

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Publication number
WO2015093356A1
WO2015093356A1 PCT/JP2014/082623 JP2014082623W WO2015093356A1 WO 2015093356 A1 WO2015093356 A1 WO 2015093356A1 JP 2014082623 W JP2014082623 W JP 2014082623W WO 2015093356 A1 WO2015093356 A1 WO 2015093356A1
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WIPO (PCT)
Prior art keywords
piezoelectric
detection electrode
piezoelectric sensor
manufacturing
detection
Prior art date
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PCT/JP2014/082623
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French (fr)
Japanese (ja)
Inventor
斉藤誠人
遠藤潤
河村秀樹
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株式会社村田製作所
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Priority to JP2015553495A priority Critical patent/JPWO2015093356A1/en
Publication of WO2015093356A1 publication Critical patent/WO2015093356A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/06—Forming electrodes or interconnections, e.g. leads or terminals
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
    • H10N30/302—Sensors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/85—Piezoelectric or electrostrictive active materials
    • H10N30/857—Macromolecular compositions

Definitions

  • the present invention relates to a method for manufacturing a piezoelectric sensor that detects that a pressure has been applied.
  • a piezoelectric sensor may be provided not only to detect a touch position on one main surface (operation surface) of the touch panel but also to detect a pressing amount on the operation surface.
  • Patent Document 1 discloses a plate-like piezoelectric sensor in which a first detection electrode and a second detection electrode are provided on both surfaces of a piezoelectric sheet (piezoelectric film).
  • the piezoelectric sensor is bonded to the other main surface opposite to the operation surface of the touch panel.
  • This piezoelectric sensor can detect the amount of pressing on the operation surface by detecting the voltage.
  • the inventor is a substrate portion on which the piezoelectric film and the first detection electrode and the second detection electrode are formed, the substrate portion sandwiching the piezoelectric film between the first detection electrode and the second detection electrode,
  • a piezoelectric sensor having a structure including a detection plate having one main surface bonded to a main surface opposite to the piezoelectric film of the substrate portion has been developed. In this structure, when the detection plate is pressed, the detection plate and the piezoelectric film bonded to the detection plate are bent in the thickness direction, and an output voltage is generated in the piezoelectric sensor.
  • An object of the present invention is to provide a method for manufacturing a piezoelectric sensor capable of suppressing variations in output voltage with respect to temperature changes.
  • the present invention relates to a method for manufacturing a piezoelectric sensor including a piezoelectric film, a substrate portion, and a detection plate.
  • This method for manufacturing a piezoelectric sensor has at least a production process and a heat treatment process.
  • the production process is performed by pasting the main surface of the substrate portion opposite to the piezoelectric film and the main surface of the detection plate that is bent in the thickness direction when pressed by a pressure-sensitive adhesive, and combining the substrate portion and the detection plate Create
  • the composite is heated.
  • the piezoelectric sensor manufactured by this manufacturing method is used in an environment with a temperature change, the output voltage of the piezoelectric sensor generated when the detection plate is pressed and the detection plate and the piezoelectric film are bent becomes the piezoelectric sensor. It is possible to suppress large variations for each individual.
  • the manufacturing method of this piezoelectric sensor includes an electrode formation step, a first pasting step, and a second pasting step.
  • the electrode formation step the first detection electrode and the second detection electrode are formed side by side on the same surface of the substrate portion.
  • a 1st sticking process sticks a piezoelectric film on the 1st detection electrode of a board
  • the second attaching step the substrate portion is folded, the second detection electrode is attached to the piezoelectric film, and the piezoelectric film is sandwiched between the first detection electrode and the second detection electrode.
  • a substrate portion on which a first detection electrode and a second detection electrode are formed, and a substrate portion with a piezoelectric film sandwiched between the first detection electrode and the second detection electrode is prepared.
  • the composite in the heat treatment step, is preferably heat-treated at a temperature of 70 ° C. or higher and 100 ° C. or lower.
  • the composite in the heat treatment step, is preferably heat-treated in an atmosphere at a pressure higher than atmospheric pressure.
  • the heating time can be shortened.
  • the composite in the heat treatment step, is preferably heat-treated for 0.5 hour or more.
  • the pressure-sensitive adhesive is preferably an acrylic pressure-sensitive adhesive.
  • the material of the detection plate is preferably glass or stainless steel.
  • the piezoelectric sensor preferably has a piezoelectric film formed of a chiral polymer.
  • the piezoelectric sensor can reliably detect the displacement of the piezoelectric film with high sensitivity.
  • the chiral polymer is preferably polylactic acid.
  • the piezoelectric sensor can reliably detect the displacement of the piezoelectric film with high sensitivity.
  • the polylactic acid is preferably L-type polylactic acid.
  • the piezoelectric sensor can reliably detect the displacement of the piezoelectric film with high sensitivity.
  • FIG. 2 is a cross-sectional view taken along line AA shown in FIG. It is a top view of the piezoelectric sensor 100 shown in FIG.
  • FIG. 4 is a cross-sectional view taken along line BB shown in FIG.
  • FIG. 4 is an exploded plan view of a sensor unit 16 of the piezoelectric sensor 100 shown in FIG. 3. It is sectional drawing at the time of the pressing force detection of the principal part of the display apparatus 10 shown in FIG. It is a flowchart which shows the manufacturing method of the piezoelectric sensor 100 shown in FIG. It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG.
  • FIG. It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. It is a back view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. It is a side view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. It is a figure which shows the relationship between the frequency
  • FIG. 1 is a plan view of a display device 10 including a piezoelectric sensor 100 according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view taken along line AA shown in FIG.
  • the display device 10 includes an operation plate 12, a spacer 14A, a spacer 14B, a detection plate 15, a plate-like sensor unit 16, a columnar pusher 17, and a columnar cushion 21.
  • the display device 10 includes a piezoelectric sensor 100 having a spacer 14 ⁇ / b> A and a spacer 14 ⁇ / b> B, a pusher 17, a cushion 21, a sensor unit 16, and a detection plate 15, which will be described in detail later. Further, the display device 10 includes a housing 11 having a size that is portable.
  • the display device 10 is, for example, a tablet or a smartphone.
  • the housing 11 has a rectangular parallelepiped shape with an open top. As shown in FIGS. 1 and 2, the casing 11 is fitted with an operation plate 12 so as to close the opening surface of the casing 11.
  • the operation plate 12 is a laminated body in which a liquid crystal panel, a touch panel, and a cover glass are laminated.
  • One main surface of the operation plate 12 (specifically, one main surface of the outermost cover glass) serves as the operation surface 101.
  • the operation plate 12 is made of a material having translucency.
  • the operation plate 12, the pusher 17, the sensor unit 16, the detection plate 15, and the cushion 21 are arranged in this order from the operation surface 101 side in the housing 11. .
  • the longitudinal direction of the operation surface 101 is referred to as the X direction
  • the short direction of the operation surface 101 is referred to as the Y direction
  • the direction perpendicular to the operation surface 101 that is, the thickness direction of the housing 11
  • the Z direction is referred to as the Z direction.
  • the spacer 14 ⁇ / b> A is disposed in the vicinity of the first side surface parallel to the X direction among the side surfaces of the housing 11.
  • the spacer 14 ⁇ / b> B is disposed in the vicinity of the second side surface (side surface facing the first side surface) of the housing 11.
  • the spacer 14 ⁇ / b> A and the spacer 14 ⁇ / b> B are disposed at a substantially central portion in the X direction of the housing 11.
  • the material of the spacer 14A and the spacer 14B is, for example, PET resin.
  • the material of the detection plate 15 is SUS (stainless steel).
  • the detection plate 15 is supported inside the housing 11 by spacers 14 ⁇ / b> A, 14 ⁇ / b> B, and a cushion 21 so that the main surface on the operation surface 101 side of the detection plate 15 is parallel to the operation surface 101 of the operation plate 12. .
  • the detection plate 15 is disposed at a substantially central portion in the X direction of the housing 11.
  • the longitudinal direction of the detection plate 15 is parallel to the Y direction.
  • the main surface opposite to the operation surface 101 of the sensor unit 16 is attached to the main surface of the detection plate 15 on the operation surface 101 side.
  • the sensor unit 16 is arranged inside the housing 11 so that the main surface on the operation surface 101 side of the sensor unit 16 is parallel to the operation surface 101 of the operation plate 12. Although details will be described later, the sensor unit 16 is attached to the detection plate 15 and constitutes a part of the piezoelectric sensor 100 (see FIG. 3 described later).
  • the pusher 17 is disposed between the operation plate 12 and the sensor unit 16 so as to contact the operation plate 12 and the sensor unit 16.
  • the pusher 17 is disposed at a substantially central portion of the detection plate 15 in the Y direction.
  • the pusher 17 transmits stress from the operation plate 12 to the detection plate 15 and the sensor unit 16.
  • the material of the pusher 17 is, for example, PET resin.
  • the cushion 21 is disposed between the bottom surface inside the housing 11 and the detection plate 15 so as to contact the bottom surface inside the housing 11 and the detection plate 15.
  • the cushion 21 is disposed at a substantially central portion of the detection plate 15 in the Y direction.
  • the cushion 21 is made of a material softer than the pusher 17.
  • the material of the cushion 21 is, for example, a foamable film.
  • the cushion 21 is disposed at substantially the same position as the pusher 17 when viewed from the Z direction (in plan view) and has substantially the same shape and size as the pusher 17. That is, the cushion 21 overlaps the pusher 17 when viewed from the Z direction (direction perpendicular to the main surface of the detection plate 15).
  • the cushion 21 supports the detection plate 15 and presses the detection plate 15 against the pusher 17 via the sensor unit 16. Thereby, even if the operation plate 12 is warped, the pressure applied to the pusher 12 can be reliably transmitted to the detection plate 15 without creating a gap between the operation plate 12 and the pusher 17.
  • FIG. 3 is a plan view of the piezoelectric sensor 100 shown in FIG. 4 is a cross-sectional view taken along line BB shown in FIG.
  • FIG. 5 is an exploded plan view of the sensor unit 16 of the piezoelectric sensor 100 shown in FIG.
  • FIG. 5A is a plan view of the piezoelectric film 31 of the sensor unit 16.
  • FIG. 5B is a plan view of the sensor unit 16 in a state where the substrate unit 36 and the substrate unit 37 are opened and the piezoelectric film 31 is removed.
  • the piezoelectric sensor 100 includes a spacer 14 ⁇ / b> A and a spacer 14 ⁇ / b> B, a detection plate 15, a sensor unit 16, a pusher 17, a cushion 21, a component mounting unit 38, and a circuit component 39. And disposed inside the housing 11.
  • the component mounting unit 38 is a part of the flexible printed circuit board 30.
  • the flexible printed circuit board 30 includes a substrate unit 36 and a substrate unit 37 that constitute a part of the sensor unit 16, and a component mounting unit 38.
  • the material of the flexible printed circuit board 30 is a resin such as polyimide.
  • the first terminal 32 and the second terminal 33 which are conductor patterns are formed on the front main surface of the component mounting portion 38. Further, a circuit component 39 is surface-mounted on the front main surface of the component mounting portion 38. The circuit component 39 is connected to the first detection electrode 34 and the second detection electrode 35 via the first terminal 32 and the second terminal 33.
  • the pusher 17 is pressed against the main surface on the operation surface 101 side in a part of the area of the sensor unit 16.
  • the main surface opposite to the operation surface 101 of the sensor unit 16 is attached to the main surface on the operation surface 101 side of the detection plate 15 with an adhesive layer 90 so that the longitudinal direction thereof is the Y direction.
  • the pressure-sensitive adhesive layer 90 is made of, for example, an epoxy adhesive.
  • the sensor unit 16 includes a piezoelectric film 31, an adhesive layer 91 and an adhesive layer 92, a first detection electrode 34, a second detection electrode 35, a substrate unit 36, and a substrate unit 37.
  • the flexible printed board 30 includes the board part 36 and the board part 37 that constitute a part of the sensor part 16 and the component mounting part 38.
  • the first detection electrode 34, the second detection electrode 35, the piezoelectric film 31, the substrate portion 36, and the substrate portion 37 each have a flat main surface and a back main surface that are flat and face each other in the thickness direction.
  • the upper side surface in FIG. 4 is referred to as a front main surface and the lower side surface is referred to as a back main surface.
  • the substrate portion 37, the second detection electrode 35, the adhesive layer 91, the piezoelectric film 31, the adhesive layer 92, the first detection electrode 34, and the substrate portion 36 are arranged in this order from the front main surface side. It is laminated over the back main surface side.
  • the second detection electrode 35 is laminated on the front main surface of the piezoelectric film 31 via the adhesive layer 91, and the substrate portion 37 is further laminated on the front main surface of the second detection electrode 35.
  • the first detection electrode 34 is laminated on the back main surface of the piezoelectric film 31 via the adhesive layer 92, and the substrate portion 36 is further laminated on the back main surface of the first detection electrode 34.
  • the second detection electrode 35, the first detection electrode 34, the piezoelectric film 31, the substrate portion 37, and the substrate portion 36 have a substantially rectangular outer shape in plan view.
  • the outer shapes of the substrate portion 37 and the substrate portion 36 are slightly larger than the outer shape of the piezoelectric film 31.
  • the substrate unit 36 and the substrate unit 37 are a part of the flexible printed circuit board 30.
  • a slit 18 ⁇ / b> A is provided at a position that partitions the substrate unit 37 and the substrate unit 36.
  • the slit 18A extends in parallel with the long side of the substrate part 37 (or the long side of the substrate part 36).
  • connecting portions 18B are provided on both sides of the slit 18A in the direction in which the slit 18A extends.
  • Each connecting portion 18 ⁇ / b> B connects the substrate portion 37 and the substrate portion 36. Note that the slit 18A and the two connecting portions 18B are not necessarily provided, and may have other shapes.
  • the second detection electrode 35 is formed on the back main surface of the substrate portion 37, and the first detection electrode 34 is formed on the front main surface of the substrate portion 36. That is, the first detection electrode 34 and the second detection electrode 35 are formed side by side on the same surface of the flexible printed circuit board 30.
  • the piezoelectric film 31 is stuck to the front main surface of the first detection electrode 34 with an adhesive layer 92.
  • the piezoelectric film 31 is attached to the back main surface of the second detection electrode 35 with an adhesive layer 91.
  • the pressure-sensitive adhesive layer 91 and the pressure-sensitive adhesive layer 92 are made of, for example, an acrylic pressure-sensitive adhesive.
  • one end of the first terminal 32 is connected to the first detection electrode 34.
  • the other end of the first terminal 32 is connected to the circuit component 39.
  • One end of the second terminal 33 is connected to the second detection electrode 35.
  • the other end of the second terminal 33 is connected to the circuit component 39.
  • the first detection electrode 34 and the second detection electrode 35 are electrically connected to the circuit component 39 via the first terminal 32 and the second terminal 33, respectively.
  • the piezoelectric film 31 is molecularly oriented in a direction 19 that forms about 45 ° with respect to the long and short sides.
  • the piezoelectric film 31 is a film mainly composed of L-type polylactic acid (PLLA).
  • PLLA is a chiral polymer whose main chain has a helical structure, and has a property of expressing piezoelectricity by being oriented in a predetermined axial direction.
  • This piezoelectricity is represented by a piezoelectric tensor component d 14 with the film thickness direction as the first axis and the PLLA molecule orientation direction as the third axis.
  • the piezoelectric film 31 having the piezoelectric tensor component d 14 is a direction intersecting the long sides and short sides in the front main surface and rear main surface, specifically about 45 ° direction with respect to the long sides and short sides, By setting the direction in which the PLLA molecules are oriented, the pressing force from the thickness direction can be detected.
  • the angle of the direction 19 in the piezoelectric film 31 is not limited to an accurate 45 ° with respect to the long side and the short side, and can be any angle close to 45 °. As the angle in the direction 19 is closer to 45 ° with respect to the long side and the short side, the pressing force from the thickness direction can be detected more efficiently.
  • approximately 45 ° in the present invention means an angle in a predetermined range centered on 45 °, for example, about 45 ° ⁇ 10 °. These specific angles may be appropriately determined according to the overall design based on the use of the displacement sensor, the characteristics of each part, and the like.
  • the piezoelectric film 31 is not limited to a film mainly composed of PLLA, and may be a film mainly composed of D-type polylactic acid (PDLA) or polyvinylidene fluoride (PVDF).
  • PDLA D-type polylactic acid
  • PVDF polyvinylidene fluoride
  • the piezoelectricity of the piezoelectric film 31 mainly composed of a chiral polymer such as PLLA or PDLA is not expressed by the polarization of ions like ferroelectrics such as PVDF and PZT, and is characteristic of molecules. It is derived from the spiral structure.
  • the chiral polymer does not need to exhibit piezoelectricity by poling treatment like other polymers such as PVDF and piezoelectric ceramics using a piezoelectric crystal thin film, and PVDF or the like has a piezoelectric constant over time. Although fluctuations are observed and in some cases the piezoelectric constant may be significantly reduced, the piezoelectric constant of the chiral polymer is very stable over time.
  • the piezoelectric film 31 mainly composed of a chiral polymer can obtain a detection voltage corresponding only to the pressing force without depending on the temperature at the detection position at the time of pressing detection.
  • chiral polymers are polymers and have flexibility, so they do not break with large displacements like piezoelectric ceramics. Therefore, the piezoelectric film 31 mainly composed of a chiral polymer is not damaged even if the displacement amount is large, and the displacement amount can be reliably detected.
  • FIG. 6 is a cross-sectional view when the pressing force of the main part of the display device 10 shown in FIG. 1 is detected.
  • FIG. 6 in order to demonstrate a mode that the operation board 12, the sensor part 16, and the detection board 15 bend, these bending is emphasized and shown.
  • the sensor unit 16 and the detection plate 15 of the piezoelectric sensor 100 are pressed in the thickness direction from the operation plate 12 via the pusher 17, and are bent in the thickness direction to generate charges in the piezoelectric film 31.
  • the detection voltage having a voltage value corresponding to the magnitude of the pressing force is a voltage polarity corresponding to the direction of the pressing force. It occurs in.
  • This detection voltage is input to the circuit component 39 via the first terminal 32 and the second terminal 33 as a press detection signal (see FIG. 3).
  • FIG. 7 is a flowchart showing a manufacturing method of the piezoelectric sensor 100 shown in FIG. 8 to 16 are plan views showing manufacturing steps of the piezoelectric sensor 100 shown in FIG.
  • a plurality of piezoelectric sensors 100 are manufactured in a lump.
  • a scene in which one piezoelectric sensor 100 is manufactured will be described in order to simplify the description.
  • a sheet-like flexible printed board 3 having a copper foil 50 attached to the entire surface of one main surface is prepared (S1).
  • the flexible printed circuit board 3 may be formed with copper foil on the entire main surface in order to provide the sensor unit 30 with a shield electrode layer that shields noise.
  • a conductor pattern is formed on one main surface of the flexible printed circuit board 3 by etching or the like (S2). Accordingly, the first detection electrode 34 connected to the first terminal 32 and the second detection electrode 35 connected to the second terminal 33 are formed side by side on the same surface of the flexible printed circuit board 3.
  • the flexible printed circuit board 3 is punched with a press die to form the flexible printed circuit board 30 having the shape shown in FIG. 10 (S3).
  • the flexible printed circuit board 30 on which the first terminal 32, the second terminal 33, the slit 18A, the connecting portion 18B, the first detection electrode 34, the second detection electrode 35, the substrate portion 36, and the substrate portion 37 are formed is prepared.
  • the main surface on the side opposite to the operation surface 101 of the main portion (the portion that becomes the sensor portion 16) of the flexible printed circuit board 30 is the first main surface on the operation surface 101 side of the detection plate 15. Affixed to the surface with an adhesive (S4).
  • the part used as the sensor part 16 is affixed on the detection board 15 with an adhesive agent, and the composite body of the sensor part 16 and the detection board 15 is created after the process of S7.
  • the circuit component 39 is surface-mounted on the front main surface of the component mounting portion 38 (S5). Accordingly, the first detection electrode 34 and the second detection electrode 35 are connected to the circuit component 39 via the first terminal 32 and the second terminal 33.
  • This pressure-sensitive adhesive may be a conductive pressure-sensitive adhesive.
  • the substrate portion 37 is folded, the second detection electrode 35 is attached to the piezoelectric film 31 with an adhesive, and the piezoelectric film 31 is interposed between the first detection electrode 34 and the second detection electrode 35. (S7).
  • This pressure-sensitive adhesive may be a conductive pressure-sensitive adhesive. Since the flexible printed board 30 is flexible and can be greatly deformed, the board portion 37 is easily folded back.
  • the flexible printed circuit board 30 on which the first detection electrode 34 and the second detection electrode 35 are formed by the steps S1 to S3 and S6 to S7 described above, and between the first detection electrode 34 and the second detection electrode 35.
  • a flexible printed circuit board 30 with a piezoelectric film 31 interposed therebetween is prepared.
  • spacers 14A and 14B are mounted on both surfaces of both ends of the detection plate 15 (S10).
  • the piezoelectric sensor 100 of the present embodiment can be manufactured through the above-described steps.
  • the piezoelectric sensor 100 including the composite body of the sensor unit 16 and the detection plate 15 is heat-treated with an autoclave (S11).
  • the piezoelectric sensor 100 is preferably heat-treated at a temperature of 70 ° C. or higher and 100 ° C. or lower for at least 0.5 hours, and more preferably 3 hours or longer.
  • the maximum value of the heating temperature is set according to the heat resistance of the piezoelectric film, and in this case, 100 ° C. or less is suitable.
  • the heating time can be shortened by heat-treating the piezoelectric sensor 100 in an atmosphere at a pressure higher than atmospheric pressure.
  • the inventor has confirmed that in the case of atmospheric pressure, which took 120 minutes at a heating temperature of 90 ° C., the pressure can be reduced to 50 minutes even at the same heating temperature if the atmospheric pressure is 10 atmospheres.
  • the piezoelectric sensor 100 manufactured by this manufacturing method is used in an environment with a temperature change, the output voltage of the piezoelectric sensor 100 generated when the detection plate 15 is pressed and the piezoelectric film 31 is bent becomes piezoelectric. It is possible to suppress a large variation for each individual sensor 100.
  • FIG. 17 is a diagram illustrating the relationship between the number of heat cycles and the output voltage in the piezoelectric sensor 100 that has not undergone the heat treatment process and the piezoelectric sensor 100 that has undergone the heat treatment process.
  • FIG. 17 shows that two piezoelectric sensors 100 that have not undergone a heat treatment process and two piezoelectric sensors 100 that have undergone a heat treatment process are prepared, and after four piezoelectric sensors 100 are exposed to a low temperature environment of ⁇ 40 degrees for 30 minutes.
  • times for 30 minutes is shown.
  • no. 2 is the piezoelectric sensor 100 that has not undergone the heat treatment process.
  • no. Reference numeral 4 denotes a piezoelectric sensor that has undergone a heat treatment process.
  • the output voltage of the piezoelectric sensor 100 generated when the detection plate 15 is pressed is different for each individual piezoelectric sensor 100.
  • the output voltage of the piezoelectric sensor 100 generated when the detection plate 15 is pressed is the piezoelectric sensor. It became clear that it was possible to suppress large variations for every 100 individuals.
  • planar shape of the piezoelectric film 31 is a rectangular shape, it is not restricted to this.
  • the planar shape of the piezoelectric film may be other planar shapes such as a square shape, a circular shape, a trapezoidal shape, a parallelogram shape, a polygonal shape of quadrilateral or more, an elliptical shape, an oval shape, or the like.
  • the material of the detection plate 15 is SUS (stainless steel), but is not limited thereto.
  • the material of the detection plate 15 may be a glass plate, for example.
  • the piezoelectric sensor 100 includes the pusher 17, the cushion 21, the spacer 14A, and the spacer 14B, but is not limited thereto. In implementation, the piezoelectric sensor 100 may not include the pusher 17, the cushion 21, the spacer 14A, and the spacer 14B.
  • the pusher 17 is disposed between the operation plate 12 and the sensor unit 16, but is not limited thereto. At the time of implementation, the operation plate 12 and the sensor unit 16 may be directly attached without arranging the pusher 17, the spacer 14A, and the spacer 14B.

Abstract

A flexible printed circuit board (3) that has a copper foil (50) affixed to the entirety of one principal surface thereof is prepared. A conductor pattern is formed on said principal surface. The flexible printed circuit board (3) is subjected to a punching process, and the principal surface of the resulting flexible printed circuit board (30) on the opposite side from a manipulation surface (101) in a main part is affixed to a first principal surface of a detection plate (15) on the side thereof facing the manipulation surface (101). A pressure-sensitive adhesive is used to apply a piezoelectric film (31) to a first detection electrode (34) on one substrate part (36). Another substrate part (37) is folded over and a second detection electrode (35) is affixed to the piezoelectric film (31), sandwiching said piezoelectric film (31) between the first detection electrode (34) and the second detection electrode (35). A composite consisting of a sensor unit (16) and the detection plate (15) is heat-treated in an autoclave.

Description

圧電センサの製造方法Method for manufacturing piezoelectric sensor
　本発明は、押圧されたことを検出する圧電センサの製造方法に関する。 The present invention relates to a method for manufacturing a piezoelectric sensor that detects that a pressure has been applied.
　従来、タッチパネルを備える表示装置では、タッチパネルの一方主面（操作面）でのタッチ位置を検出するだけでなく、操作面での押圧量を検出するために、圧電センサが設けられることがある。 Conventionally, in a display device including a touch panel, a piezoelectric sensor may be provided not only to detect a touch position on one main surface (operation surface) of the touch panel but also to detect a pressing amount on the operation surface.
　例えば特許文献１には、圧電性シート（圧電フィルム）の両面それぞれに第１検出電極と第２検出電極を設けた板状の圧電センサが開示されている。この圧電センサは例えば、タッチパネルの操作面とは逆側の他方主面に接合される。 For example, Patent Document 1 discloses a plate-like piezoelectric sensor in which a first detection electrode and a second detection electrode are provided on both surfaces of a piezoelectric sheet (piezoelectric film). For example, the piezoelectric sensor is bonded to the other main surface opposite to the operation surface of the touch panel.
　タッチパネルの操作面が押圧されることによって圧電性シート（圧電フィルム）がタッチパネルを介して押圧されると、圧電性シートの第１検出電極と第２検出電極間に電圧が生じる。この圧電センサは、その電圧を検出することで、操作面での押圧量を検出できる。 When the operation surface of the touch panel is pressed and the piezoelectric sheet (piezoelectric film) is pressed via the touch panel, a voltage is generated between the first detection electrode and the second detection electrode of the piezoelectric sheet. This piezoelectric sensor can detect the amount of pressing on the operation surface by detecting the voltage.
国際公開２０１２／１３７８９７号International Publication No. 2012/137897
　前記第１検出電極と第２検出電極は、絶縁体で覆って、保護されることが望ましい。そこで、発明者は、圧電フィルムと、第１検出電極および第２検出電極が形成された基板部であって、第１検出電極と第２検出電極の間に圧電フィルムを挟んだ基板部と、基板部の圧電フィルムとは逆側の主面に一方の主面が接合された検出板と、を備えた構造の圧電センサを開発している。この構造では、検出板が押圧されることによって、検出板と検出板に接合されている圧電フィルムとが厚み方向に撓み、圧電センサに出力電圧が生じる。 It is desirable that the first detection electrode and the second detection electrode are covered with an insulator to be protected. Therefore, the inventor is a substrate portion on which the piezoelectric film and the first detection electrode and the second detection electrode are formed, the substrate portion sandwiching the piezoelectric film between the first detection electrode and the second detection electrode, A piezoelectric sensor having a structure including a detection plate having one main surface bonded to a main surface opposite to the piezoelectric film of the substrate portion has been developed. In this structure, when the detection plate is pressed, the detection plate and the piezoelectric film bonded to the detection plate are bent in the thickness direction, and an output voltage is generated in the piezoelectric sensor.
　しかしながら、この構造の圧電センサに対してヒートサイクル試験を行った結果、圧電センサの出力電圧が、圧電センサの個体毎に大きくバラつくという問題が明らかとなった。 However, as a result of conducting a heat cycle test on the piezoelectric sensor having this structure, the problem that the output voltage of the piezoelectric sensor varies greatly from one individual piezoelectric sensor to another is clarified.
　本発明の目的は、温度変化に対する出力電圧のバラつきを抑えることができる圧電センサの製造方法を提供することにある。 An object of the present invention is to provide a method for manufacturing a piezoelectric sensor capable of suppressing variations in output voltage with respect to temperature changes.
　本発明は、圧電フィルムと基板部と検出板とを備える圧電センサの製造方法に関するものである。この圧電センサの製造方法は、少なくとも、作成工程、および熱処理工程を有する。 The present invention relates to a method for manufacturing a piezoelectric sensor including a piezoelectric film, a substrate portion, and a detection plate. This method for manufacturing a piezoelectric sensor has at least a production process and a heat treatment process.
　作成工程は、基板部の圧電フィルムとは逆側の主面と、押圧されることによって厚み方向に撓む検出板の主面と、を粘着剤によって貼付し、基板部及び検出板の複合体を作成する。 The production process is performed by pasting the main surface of the substrate portion opposite to the piezoelectric film and the main surface of the detection plate that is bent in the thickness direction when pressed by a pressure-sensitive adhesive, and combining the substrate portion and the detection plate Create
　熱処理工程は、複合体を加熱処理する。 In the heat treatment step, the composite is heated.
　この製造方法では、基板部及び検出板の複合体に対してあらかじめ加熱処理を行うことで複合体の製造過程で生じた様々な内部応力を緩和して、熱エージング特性に優れた複合体を得ることができる。 In this manufacturing method, various internal stresses generated in the manufacturing process of the composite are relieved by heat-treating the composite of the substrate portion and the detection plate in advance, thereby obtaining a composite having excellent thermal aging characteristics. be able to.
　よって、この製造方法で製造された圧電センサが温度変化のある環境下で使用されても、検出板が押圧され、検出板および圧電フィルムが撓むことによって生じる圧電センサの出力電圧が、圧電センサの個体毎に大きくバラつくことを抑制できる。 Therefore, even when the piezoelectric sensor manufactured by this manufacturing method is used in an environment with a temperature change, the output voltage of the piezoelectric sensor generated when the detection plate is pressed and the detection plate and the piezoelectric film are bent becomes the piezoelectric sensor. It is possible to suppress large variations for each individual.
　したがって、この製造方法によれば、温度変化に対する圧電センサの出力電圧のバラつきを抑えることができる。 Therefore, according to this manufacturing method, variations in the output voltage of the piezoelectric sensor with respect to temperature changes can be suppressed.
　また、この圧電センサの製造方法は、電極形成工程、第１貼付工程、第２貼付工程を含むことが好ましい。電極形成工程は、第１検出電極および第２検出電極を基板部の同じ面に並んで離れて形成する。第１貼付工程は、基板部の第１検出電極上に圧電フィルムを貼付する。第２貼付工程は、基板部を折り返し、第２検出電極を圧電フィルムに貼付し、第１検出電極と第２検出電極の間に圧電フィルムを挟む。 Moreover, it is preferable that the manufacturing method of this piezoelectric sensor includes an electrode formation step, a first pasting step, and a second pasting step. In the electrode formation step, the first detection electrode and the second detection electrode are formed side by side on the same surface of the substrate portion. A 1st sticking process sticks a piezoelectric film on the 1st detection electrode of a board | substrate part. In the second attaching step, the substrate portion is folded, the second detection electrode is attached to the piezoelectric film, and the piezoelectric film is sandwiched between the first detection electrode and the second detection electrode.
　この製造方法では、第１検出電極および第２検出電極が形成された基板部であって、第１検出電極と第２検出電極の間に圧電フィルムを挟んだ基板部が用意される。 In this manufacturing method, a substrate portion on which a first detection electrode and a second detection electrode are formed, and a substrate portion with a piezoelectric film sandwiched between the first detection electrode and the second detection electrode is prepared.
　また、本発明において、熱処理工程は、複合体を、７０℃以上１００℃以下の温度で加熱処理することが好ましい。 In the present invention, in the heat treatment step, the composite is preferably heat-treated at a temperature of 70 ° C. or higher and 100 ° C. or lower.
　また、本発明において、熱処理工程は、複合体を、大気圧より高い圧力の雰囲気下で加熱処理することが好ましい。 In the present invention, in the heat treatment step, the composite is preferably heat-treated in an atmosphere at a pressure higher than atmospheric pressure.
　この製造方法では、加熱時間を短縮することができる。 In this manufacturing method, the heating time can be shortened.
　また、本発明において、熱処理工程は、複合体を、０．５時間以上、加熱処理することが好ましい。 In the present invention, in the heat treatment step, the composite is preferably heat-treated for 0.5 hour or more.
　また、本発明において、粘着剤は、アクリル系粘着剤であることが好ましい。 In the present invention, the pressure-sensitive adhesive is preferably an acrylic pressure-sensitive adhesive.
　また、本発明において、検出板の材料は、ガラスまたはステンレススチールであることが好ましい。 In the present invention, the material of the detection plate is preferably glass or stainless steel.
　また、本発明において、圧電センサは、キラル高分子によって形成された圧電フィルムを有することが好ましい。 In the present invention, the piezoelectric sensor preferably has a piezoelectric film formed of a chiral polymer.
　この製造方法では、圧電センサは、圧電フィルムの変位を、確実且つ高感度に検知することができる。 In this manufacturing method, the piezoelectric sensor can reliably detect the displacement of the piezoelectric film with high sensitivity.
　また、本発明において、キラル高分子は、ポリ乳酸であることが好ましい。 In the present invention, the chiral polymer is preferably polylactic acid.
　この製造方法では、圧電センサは、圧電フィルムの変位を、確実且つ高感度に検知することができる。 In this manufacturing method, the piezoelectric sensor can reliably detect the displacement of the piezoelectric film with high sensitivity.
　また、本発明において、ポリ乳酸は、Ｌ型ポリ乳酸であることが好ましい。 In the present invention, the polylactic acid is preferably L-type polylactic acid.
　この製造方法では、圧電センサは、圧電フィルムの変位を、確実且つ高感度に検知することができる。 In this manufacturing method, the piezoelectric sensor can reliably detect the displacement of the piezoelectric film with high sensitivity.
　この発明によれば、温度変化に対する圧電センサの出力電圧のバラつきを抑えることができる。 According to the present invention, variations in the output voltage of the piezoelectric sensor with respect to temperature changes can be suppressed.
本発明の実施形態に係る圧電センサ１００を備える表示装置１０の平面図である。It is a top view of the display apparatus 10 provided with the piezoelectric sensor 100 which concerns on embodiment of this invention. 図１に示すＡ－Ａ線の断面図である。FIG. 2 is a cross-sectional view taken along line AA shown in FIG. 図１に示す圧電センサ１００の平面図である。It is a top view of the piezoelectric sensor 100 shown in FIG. 図３に示すＢ－Ｂ線の断面図である。FIG. 4 is a cross-sectional view taken along line BB shown in FIG. 図３に示す圧電センサ１００のセンサ部１６の分解平面図である。FIG. 4 is an exploded plan view of a sensor unit 16 of the piezoelectric sensor 100 shown in FIG. 3. 図１に示す表示装置１０の主要部の押圧力検出時の断面図である。It is sectional drawing at the time of the pressing force detection of the principal part of the display apparatus 10 shown in FIG. 図１に示す圧電センサ１００の製造方法を示すフローチャートである。It is a flowchart which shows the manufacturing method of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す平面図である。It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す平面図である。It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す平面図である。It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す平面図である。It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す平面図である。It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す平面図である。It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す平面図である。It is a top view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す裏面図である。It is a back view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 図１に示す圧電センサ１００の製造工程を示す側面図である。It is a side view which shows the manufacturing process of the piezoelectric sensor 100 shown in FIG. 加熱処理工程を経ていない圧電センサ１００と加熱処理工程を経た圧電センサ１００とにおける、ヒートサイクルの回数と出力電圧との関係を示す図である。It is a figure which shows the relationship between the frequency | count of a heat cycle, and the output voltage in the piezoelectric sensor 100 which has not passed through the heat processing process, and the piezoelectric sensor 100 which passed through the heat processing process.
　以下、本発明の実施形態に係る圧電センサについて説明する。図１は、本発明の実施形態に係る圧電センサ１００を備える表示装置１０の平面図である。図２は、図１に示すＡ－Ａ線の断面図である。 Hereinafter, a piezoelectric sensor according to an embodiment of the present invention will be described. FIG. 1 is a plan view of a display device 10 including a piezoelectric sensor 100 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA shown in FIG.
　表示装置１０は、操作板１２、スペーサ１４Ａ、スペーサ１４Ｂ、検出板１５、板状のセンサ部１６、柱状の押し子１７、及び柱状のクッション２１を備える。表示装置１０は、詳細は後述するが、スペーサ１４Ａ及びスペーサ１４Ｂ、押し子１７、クッション２１、センサ部１６及び検出板１５を有する圧電センサ１００を備える。さらに、表示装置１０は、携帯可能な程度の大きさからなる筐体１１を備える。表示装置１０は、例えばタブレットやスマートフォンである。 The display device 10 includes an operation plate 12, a spacer 14A, a spacer 14B, a detection plate 15, a plate-like sensor unit 16, a columnar pusher 17, and a columnar cushion 21. The display device 10 includes a piezoelectric sensor 100 having a spacer 14 </ b> A and a spacer 14 </ b> B, a pusher 17, a cushion 21, a sensor unit 16, and a detection plate 15, which will be described in detail later. Further, the display device 10 includes a housing 11 having a size that is portable. The display device 10 is, for example, a tablet or a smartphone.
　筐体１１は、天面が開口する直方体形状からなる。筐体１１には、図１、図２に示すように、筐体１１の開口面を塞ぐよう操作板１２が嵌め合わされている。操作板１２は、液晶パネル、タッチパネル及びカバーガラスが積層された積層体である。操作板１２の一方の主面（詳しくは最外層のカバーガラスの一方の主面）が操作面１０１となる。操作板１２は、透光性を有する材料からなる。 The housing 11 has a rectangular parallelepiped shape with an open top. As shown in FIGS. 1 and 2, the casing 11 is fitted with an operation plate 12 so as to close the opening surface of the casing 11. The operation plate 12 is a laminated body in which a liquid crystal panel, a touch panel, and a cover glass are laminated. One main surface of the operation plate 12 (specifically, one main surface of the outermost cover glass) serves as the operation surface 101. The operation plate 12 is made of a material having translucency.
　筐体１１内には、図１、図２に示すように、操作面１０１側から、操作板１２、押し子１７、センサ部１６、検出板１５、及びクッション２１がこの順番に配置されている。 As shown in FIGS. 1 and 2, the operation plate 12, the pusher 17, the sensor unit 16, the detection plate 15, and the cushion 21 are arranged in this order from the operation surface 101 side in the housing 11. .
　なお、以下では、操作面１０１の長手方向をＸ方向と称し、操作面１０１の短手方向をＹ方向と称し、操作面１０１に垂直な方向（即ち筐体１１の厚み方向）をＺ方向と称することがある。 Hereinafter, the longitudinal direction of the operation surface 101 is referred to as the X direction, the short direction of the operation surface 101 is referred to as the Y direction, and the direction perpendicular to the operation surface 101 (that is, the thickness direction of the housing 11) is referred to as the Z direction. Sometimes called.
　スペーサ１４Ａは、筐体１１の側面のうちＸ方向と平行な第１の側面付近に配置されている。スペーサ１４Ｂは、筐体１１の第２の側面（第１の側面に対向する側面）付近に配置されている。スペーサ１４Ａ及びスペーサ１４Ｂは、筐体１１のＸ方向の略中央部に配置されている。スペーサ１４Ａ及びスペーサ１４Ｂの材料は、例えばＰＥＴ樹脂である。 The spacer 14 </ b> A is disposed in the vicinity of the first side surface parallel to the X direction among the side surfaces of the housing 11. The spacer 14 </ b> B is disposed in the vicinity of the second side surface (side surface facing the first side surface) of the housing 11. The spacer 14 </ b> A and the spacer 14 </ b> B are disposed at a substantially central portion in the X direction of the housing 11. The material of the spacer 14A and the spacer 14B is, for example, PET resin.
　検出板１５の材料は、ＳＵＳ（ステンレススチール）である。検出板１５は、検出板１５の操作面１０１側の主面が操作板１２の操作面１０１と平行になるように、筐体１１の内部にスペーサ１４Ａ，スペーサ１４Ｂ及びクッション２１で支持されている。 The material of the detection plate 15 is SUS (stainless steel). The detection plate 15 is supported inside the housing 11 by spacers 14 </ b> A, 14 </ b> B, and a cushion 21 so that the main surface on the operation surface 101 side of the detection plate 15 is parallel to the operation surface 101 of the operation plate 12. .
　そのため、検出板１５と操作板１２との間および検出板１５と筐体１１内部の底面との間にはスペースが形成されている。なお、検出板１５は、筐体１１のＸ方向の略中央部に配置されている。検出板１５の長手方向は、Ｙ方向に平行になっている。 Therefore, a space is formed between the detection plate 15 and the operation plate 12 and between the detection plate 15 and the bottom surface inside the housing 11. The detection plate 15 is disposed at a substantially central portion in the X direction of the housing 11. The longitudinal direction of the detection plate 15 is parallel to the Y direction.
　センサ部１６の操作面１０１とは逆側の主面は、検出板１５の操作面１０１側の主面に貼付されている。センサ部１６は、センサ部１６の操作面１０１側の主面が操作板１２の操作面１０１と平行になるように、筐体１１の内部に配置されている。詳細は後述するが、センサ部１６は、検出板１５に貼付されて、圧電センサ１００の一部を構成する（後述の図３参照）。 The main surface opposite to the operation surface 101 of the sensor unit 16 is attached to the main surface of the detection plate 15 on the operation surface 101 side. The sensor unit 16 is arranged inside the housing 11 so that the main surface on the operation surface 101 side of the sensor unit 16 is parallel to the operation surface 101 of the operation plate 12. Although details will be described later, the sensor unit 16 is attached to the detection plate 15 and constitutes a part of the piezoelectric sensor 100 (see FIG. 3 described later).
　押し子１７は、操作板１２およびセンサ部１６に当接するよう、操作板１２とセンサ部１６との間に配置されている。押し子１７は、Ｙ方向において検出板１５の略中央部に配置されている。押し子１７は、操作板１２から検出板１５及びセンサ部１６へ応力を伝達する。押し子１７の材料は、例えばＰＥＴ樹脂である。 The pusher 17 is disposed between the operation plate 12 and the sensor unit 16 so as to contact the operation plate 12 and the sensor unit 16. The pusher 17 is disposed at a substantially central portion of the detection plate 15 in the Y direction. The pusher 17 transmits stress from the operation plate 12 to the detection plate 15 and the sensor unit 16. The material of the pusher 17 is, for example, PET resin.
　クッション２１は、筐体１１内部の底面および検出板１５に当接するよう、筐体１１内部の底面と検出板１５との間に配置されている。クッション２１は、Ｙ方向において検出板１５の略中央部に配置されている。クッション２１は、押し子１７より柔らかい材料からなる。クッション２１の材料は、例えば発泡性フィルムである。 The cushion 21 is disposed between the bottom surface inside the housing 11 and the detection plate 15 so as to contact the bottom surface inside the housing 11 and the detection plate 15. The cushion 21 is disposed at a substantially central portion of the detection plate 15 in the Y direction. The cushion 21 is made of a material softer than the pusher 17. The material of the cushion 21 is, for example, a foamable film.
　クッション２１は、Ｚ方向から見て（平面視して）、押し子１７とほぼ同一の位置に配置され、押し子１７とほぼ同一の形状および大きさを有する。すなわち、クッション２１は、Ｚ方向（検出板１５の主面に垂直な方向）から見て、押し子１７と重なる。 The cushion 21 is disposed at substantially the same position as the pusher 17 when viewed from the Z direction (in plan view) and has substantially the same shape and size as the pusher 17. That is, the cushion 21 overlaps the pusher 17 when viewed from the Z direction (direction perpendicular to the main surface of the detection plate 15).
　クッション２１は、検出板１５を支持し、センサ部１６を介して検出板１５を押し子１７に押し当てる。これにより、操作板１２に反りがあったとしても、操作板１２と押し子１７の間に隙間を作ることなく、押し子１２にかかる押圧を検出板１５に確実に伝えることができる。 The cushion 21 supports the detection plate 15 and presses the detection plate 15 against the pusher 17 via the sensor unit 16. Thereby, even if the operation plate 12 is warped, the pressure applied to the pusher 12 can be reliably transmitted to the detection plate 15 without creating a gap between the operation plate 12 and the pusher 17.
　次に、圧電センサ１００の構成について詳述する。 Next, the configuration of the piezoelectric sensor 100 will be described in detail.
　図３は、図１に示す圧電センサ１００の平面図である。図４は、図３に示すＢ－Ｂ線の断面図である。図５は、図３に示す圧電センサ１００のセンサ部１６の分解平面図である。図５（Ａ）は、センサ部１６の圧電フィルム３１の平面図である。図５（Ｂ）は、基板部３６及び基板部３７を開いて圧電フィルム３１を取り外した状態のセンサ部１６の平面図である。 FIG. 3 is a plan view of the piezoelectric sensor 100 shown in FIG. 4 is a cross-sectional view taken along line BB shown in FIG. FIG. 5 is an exploded plan view of the sensor unit 16 of the piezoelectric sensor 100 shown in FIG. FIG. 5A is a plan view of the piezoelectric film 31 of the sensor unit 16. FIG. 5B is a plan view of the sensor unit 16 in a state where the substrate unit 36 and the substrate unit 37 are opened and the piezoelectric film 31 is removed.
　図３、図４に示すように、圧電センサ１００は、スペーサ１４Ａ及びスペーサ１４Ｂと、検出板１５と、センサ部１６と、押し子１７と、クッション２１と、部品実装部３８と、回路部品３９と、を備え、筐体１１の内部に配置されている。部品実装部３８は、フレキシブルプリント基板３０の一部である。フレキシブルプリント基板３０は、センサ部１６の一部を構成する基板部３６及び基板部３７と部品実装部３８とからなる。フレキシブルプリント基板３０の材料は、ポリイミド等の樹脂である。 As shown in FIGS. 3 and 4, the piezoelectric sensor 100 includes a spacer 14 </ b> A and a spacer 14 </ b> B, a detection plate 15, a sensor unit 16, a pusher 17, a cushion 21, a component mounting unit 38, and a circuit component 39. And disposed inside the housing 11. The component mounting unit 38 is a part of the flexible printed circuit board 30. The flexible printed circuit board 30 includes a substrate unit 36 and a substrate unit 37 that constitute a part of the sensor unit 16, and a component mounting unit 38. The material of the flexible printed circuit board 30 is a resin such as polyimide.
　部品実装部３８の表主面には、導体パターンである第１端子３２および第２端子３３が形成されている。さらに、部品実装部３８の表主面には、回路部品３９が表面実装されている。回路部品３９は、第１端子３２及び第２端子３３を介して第１検出電極３４と第２検出電極３５とに接続されている。 The first terminal 32 and the second terminal 33 which are conductor patterns are formed on the front main surface of the component mounting portion 38. Further, a circuit component 39 is surface-mounted on the front main surface of the component mounting portion 38. The circuit component 39 is connected to the first detection electrode 34 and the second detection electrode 35 via the first terminal 32 and the second terminal 33.
　押し子１７は、センサ部１６の領域の一部における、操作面１０１側の主面に、押し当てられている。 The pusher 17 is pressed against the main surface on the operation surface 101 side in a part of the area of the sensor unit 16.
　センサ部１６の操作面１０１とは逆側の主面は、その長手方向がＹ方向になるように、検出板１５の操作面１０１側の主面に、粘着剤層９０によって貼付されている。粘着剤層９０は例えば、エポキシ性接着剤で構成される。 The main surface opposite to the operation surface 101 of the sensor unit 16 is attached to the main surface on the operation surface 101 side of the detection plate 15 with an adhesive layer 90 so that the longitudinal direction thereof is the Y direction. The pressure-sensitive adhesive layer 90 is made of, for example, an epoxy adhesive.
　図３～図５に示すように、センサ部１６は、圧電フィルム３１、粘着剤層９１及び粘着剤層９２、第１検出電極３４、第２検出電極３５、基板部３６、及び基板部３７を備える。前述したように、フレキシブルプリント基板３０は、センサ部１６の一部を構成する基板部３６及び基板部３７と部品実装部３８とからなる。 As shown in FIGS. 3 to 5, the sensor unit 16 includes a piezoelectric film 31, an adhesive layer 91 and an adhesive layer 92, a first detection electrode 34, a second detection electrode 35, a substrate unit 36, and a substrate unit 37. Prepare. As described above, the flexible printed board 30 includes the board part 36 and the board part 37 that constitute a part of the sensor part 16 and the component mounting part 38.
　第１検出電極３４、第２検出電極３５、圧電フィルム３１、基板部３６、および基板部３７は、それぞれ平板状で厚み方向に対向する表主面および裏主面を備える。なお、図４中の上側面を表主面、下側面を裏主面と称する。 The first detection electrode 34, the second detection electrode 35, the piezoelectric film 31, the substrate portion 36, and the substrate portion 37 each have a flat main surface and a back main surface that are flat and face each other in the thickness direction. In addition, the upper side surface in FIG. 4 is referred to as a front main surface and the lower side surface is referred to as a back main surface.
　図４に示すように、基板部３７、第２検出電極３５、粘着剤層９１、圧電フィルム３１、粘着剤層９２、第１検出電極３４、及び基板部３６は、この順に表主面側から裏主面側にかけて積層されている。 As shown in FIG. 4, the substrate portion 37, the second detection electrode 35, the adhesive layer 91, the piezoelectric film 31, the adhesive layer 92, the first detection electrode 34, and the substrate portion 36 are arranged in this order from the front main surface side. It is laminated over the back main surface side.
　具体的には、圧電フィルム３１の表主面に第２検出電極３５が粘着剤層９１を介して積層され、第２検出電極３５の表主面にさらに基板部３７が積層されている。また、圧電フィルム３１の裏主面に第１検出電極３４が粘着剤層９２を介して積層され、第１検出電極３４の裏主面にさらに基板部３６が積層されている。 Specifically, the second detection electrode 35 is laminated on the front main surface of the piezoelectric film 31 via the adhesive layer 91, and the substrate portion 37 is further laminated on the front main surface of the second detection electrode 35. Further, the first detection electrode 34 is laminated on the back main surface of the piezoelectric film 31 via the adhesive layer 92, and the substrate portion 36 is further laminated on the back main surface of the first detection electrode 34.
　図５に示すように、第２検出電極３５、第１検出電極３４、圧電フィルム３１、基板部３７、および基板部３６は、それぞれの平面視した外形状が概略長方形状である。ここでは、基板部３７および基板部３６の外形状は、圧電フィルム３１の外形状より若干大きい。 As shown in FIG. 5, the second detection electrode 35, the first detection electrode 34, the piezoelectric film 31, the substrate portion 37, and the substrate portion 36 have a substantially rectangular outer shape in plan view. Here, the outer shapes of the substrate portion 37 and the substrate portion 36 are slightly larger than the outer shape of the piezoelectric film 31.
　図３、図５に示すように、基板部３６及び基板部３７は、フレキシブルプリント基板３０の一部である。フレキシブルプリント基板３０において基板部３７と基板部３６との間を区画する位置にはスリット１８Ａが設けられている。 3 and 5, the substrate unit 36 and the substrate unit 37 are a part of the flexible printed circuit board 30. In the flexible printed circuit board 30, a slit 18 </ b> A is provided at a position that partitions the substrate unit 37 and the substrate unit 36.
　スリット１８Ａは、基板部３７の長辺（又は基板部３６の長辺）と平行に延びている。フレキシブルプリント基板３０において、スリット１８Ａが延びる方向でのスリット１８Ａの両側には連結部１８Ｂがそれぞれ設けられている。各連結部１８Ｂは、基板部３７と基板部３６とを連結している。なお、スリット１８Ａおよび２つの連結部１８Ｂは、必ずしも設けられなくてもよく、その他の形状であってもよい。 The slit 18A extends in parallel with the long side of the substrate part 37 (or the long side of the substrate part 36). In the flexible printed circuit board 30, connecting portions 18B are provided on both sides of the slit 18A in the direction in which the slit 18A extends. Each connecting portion 18 </ b> B connects the substrate portion 37 and the substrate portion 36. Note that the slit 18A and the two connecting portions 18B are not necessarily provided, and may have other shapes.
　基板部３７の裏主面には、第２検出電極３５が形成されており、基板部３６の表主面には、第１検出電極３４が形成されている。すなわち、第１検出電極３４及び第２検出電極３５は、フレキシブルプリント基板３０の同じ面に並んで離れて形成されている。 The second detection electrode 35 is formed on the back main surface of the substrate portion 37, and the first detection electrode 34 is formed on the front main surface of the substrate portion 36. That is, the first detection electrode 34 and the second detection electrode 35 are formed side by side on the same surface of the flexible printed circuit board 30.
　図４に示すように、第１検出電極３４の表主面には、圧電フィルム３１が粘着剤層９２によって貼付されている。また、第２検出電極３５の裏主面には、圧電フィルム３１が粘着剤層９１によって貼付されている。 As shown in FIG. 4, the piezoelectric film 31 is stuck to the front main surface of the first detection electrode 34 with an adhesive layer 92. The piezoelectric film 31 is attached to the back main surface of the second detection electrode 35 with an adhesive layer 91.
　粘着剤層９１及び粘着剤層９２は、例えばアクリル系粘着剤で構成される。 The pressure-sensitive adhesive layer 91 and the pressure-sensitive adhesive layer 92 are made of, for example, an acrylic pressure-sensitive adhesive.
　図５に示すように、第１端子３２の一端は、第１検出電極３４に接続されている。一方、第１端子３２の他端は、回路部品３９に接続されている。そして、第２端子３３の一端は、第２検出電極３５に接続されている。一方、第２端子３３の他端は、回路部品３９に接続されている。 As shown in FIG. 5, one end of the first terminal 32 is connected to the first detection electrode 34. On the other hand, the other end of the first terminal 32 is connected to the circuit component 39. One end of the second terminal 33 is connected to the second detection electrode 35. On the other hand, the other end of the second terminal 33 is connected to the circuit component 39.
　したがって、第１検出電極３４及び第２検出電極３５は、それぞれ第１端子３２及び第２端子３３を介して回路部品３９に電気的に接続されている。 Therefore, the first detection electrode 34 and the second detection electrode 35 are electrically connected to the circuit component 39 via the first terminal 32 and the second terminal 33, respectively.
　次に、圧電フィルム３１の構成について詳述する。 Next, the configuration of the piezoelectric film 31 will be described in detail.
　圧電フィルム３１は、長辺および短辺に対して約４５°を成す方向１９へ分子配向している。圧電フィルム３１は、Ｌ型ポリ乳酸（ＰＬＬＡ）を主材料とするフィルムである。ＰＬＬＡは、主鎖が螺旋構造を有するキラル高分子であり、所定の軸方向に配向させることで圧電性を発現する性質を有している。この圧電性は、フィルムの厚み方向を第１軸とし、ＰＬＬＡの分子が配向する方向を第３軸として圧電テンソル成分ｄ１４で表わされる。 The piezoelectric film 31 is molecularly oriented in a direction 19 that forms about 45 ° with respect to the long and short sides. The piezoelectric film 31 is a film mainly composed of L-type polylactic acid (PLLA). PLLA is a chiral polymer whose main chain has a helical structure, and has a property of expressing piezoelectricity by being oriented in a predetermined axial direction. This piezoelectricity is represented by a piezoelectric tensor component d 14 with the film thickness direction as the first axis and the PLLA molecule orientation direction as the third axis.
　この圧電テンソル成分ｄ１４を有する圧電フィルム３１においては、表主面および裏主面において長辺および短辺に対して交差する方向、具体的には長辺および短辺に対する約４５°方向を、ＰＬＬＡの分子が配向する方向とすることで、厚み方向からの押圧力を検出することができる。 In the piezoelectric film 31 having the piezoelectric tensor component d 14 is a direction intersecting the long sides and short sides in the front main surface and rear main surface, specifically about 45 ° direction with respect to the long sides and short sides, By setting the direction in which the PLLA molecules are oriented, the pressing force from the thickness direction can be detected.
　ただし、圧電フィルム３１における方向１９の角度は、長辺および短辺に対して正確な４５°に限られることなく、４５°に近い任意の角度とすることができる。方向１９の角度が、長辺および短辺に対して４５°に近い角度であるほど、厚み方向からの押圧力を効率的に検出することができる。 However, the angle of the direction 19 in the piezoelectric film 31 is not limited to an accurate 45 ° with respect to the long side and the short side, and can be any angle close to 45 °. As the angle in the direction 19 is closer to 45 ° with respect to the long side and the short side, the pressing force from the thickness direction can be detected more efficiently.
　したがって、本発明でいう略４５°とは、例えば４５°±１０°程度の４５°を中心とする所定範囲の角度をいう。これらの具体的な角度は、変位センサの用途や各部の特性などに基づいて全体の設計に応じて適宜決定するとよい。 Therefore, approximately 45 ° in the present invention means an angle in a predetermined range centered on 45 °, for example, about 45 ° ± 10 °. These specific angles may be appropriately determined according to the overall design based on the use of the displacement sensor, the characteristics of each part, and the like.
　なお、圧電フィルム３１は、ＰＬＬＡを主材料とするフィルムに限られず、Ｄ型ポリ乳酸（ＰＤＬＡ）や、ポリフッ化ビニルデン（ＰＶＤＦ）を主材料とするフィルムであってもよい。ただし、ＰＬＬＡやＰＤＬＡのようなキラル高分子を主材料とする圧電フィルム３１の圧電性は、ＰＶＤＦやＰＺＴ等の強誘電体のようにイオンの分極によって発現するものではなく、分子の特徴的な構造である螺旋構造に由来するものである。 The piezoelectric film 31 is not limited to a film mainly composed of PLLA, and may be a film mainly composed of D-type polylactic acid (PDLA) or polyvinylidene fluoride (PVDF). However, the piezoelectricity of the piezoelectric film 31 mainly composed of a chiral polymer such as PLLA or PDLA is not expressed by the polarization of ions like ferroelectrics such as PVDF and PZT, and is characteristic of molecules. It is derived from the spiral structure.
　したがって、キラル高分子は、ＰＶＤＦ等の他のポリマーや、圧電結晶薄膜を用いた圧電セラミックスのように、ポーリング処理によって圧電性を発現させる必要がなく、また、ＰＶＤＦ等は経時的に圧電定数の変動が見られ、場合によっては圧電定数が著しく低下する場合があるが、キラル高分子の圧電定数は経時的に極めて安定している。 Therefore, the chiral polymer does not need to exhibit piezoelectricity by poling treatment like other polymers such as PVDF and piezoelectric ceramics using a piezoelectric crystal thin film, and PVDF or the like has a piezoelectric constant over time. Although fluctuations are observed and in some cases the piezoelectric constant may be significantly reduced, the piezoelectric constant of the chiral polymer is very stable over time.
　さらには、キラル高分子は、他の強誘電性の圧電体で生じる焦電性が生じることがない。したがって、キラル高分子を主材料とする圧電フィルム３１は、押圧検出時に検出位置の温度に依存することなく押圧力のみに応じた検出電圧を得ることができる。 Furthermore, the pyroelectric property generated in other ferroelectric piezoelectric materials does not occur in the chiral polymer. Therefore, the piezoelectric film 31 mainly composed of a chiral polymer can obtain a detection voltage corresponding only to the pressing force without depending on the temperature at the detection position at the time of pressing detection.
　また、キラル高分子はポリマーであり、柔軟性を有するので、圧電セラミックスのように、大きな変位で破損することがない。したがって、キラル高分子を主材料とする圧電フィルム３１は、変位量が大きくても破損することがなく、確実に変位量を検出することができる。 In addition, chiral polymers are polymers and have flexibility, so they do not break with large displacements like piezoelectric ceramics. Therefore, the piezoelectric film 31 mainly composed of a chiral polymer is not damaged even if the displacement amount is large, and the displacement amount can be reliably detected.
　また、ＰＬＬＡは比誘電率が約２．５と非常に低いため、ｄを圧電定数とし、εＴを誘電率とすると、圧電出力定数（＝圧電ｇ定数、ｇ＝ｄ／εＴ）が大きな値となる。ここで、誘電率ε３３ Ｔ＝１３×ε０，圧電テンソル成分ｄ３１＝２５ｐＣ／ＮであるＰＶＤＦの圧電ｇ定数は、上述の式から、ｇ３１＝０．２１７２Ｖｍ／Ｎとなる。 Since PLLA has a very low relative dielectric constant of about 2.5, the piezoelectric output constant (= piezoelectric g constant, g = d / ε T ) is large when d is a piezoelectric constant and ε T is a dielectric constant. Value. Here, the piezoelectric g constant of PVDF having a dielectric constant ε 33 T = 13 × ε 0 and a piezoelectric tensor component d 31 = 25 pC / N is g 31 = 0.2172 Vm / N from the above formula.
　一方、圧電テンソル成分ｄ１４＝１０ｐＣ／ＮであるＰＬＬＡの圧電ｇ定数をｇ３１に換算して求めると、ｄ１４＝２×ｄ３１であるので、ｄ３１＝５ｐＣ／Ｎとなり、圧電ｇ定数は、ｇ３１＝０．２２５８Ｖｍ／Ｎとなる。したがって、圧電テンソル成分ｄ１４＝１０ｐＣ／ＮのＰＬＬＡで、ＰＶＤＦと同様の十分なセンサ感度を得ることができる。 On the other hand, when the piezoelectric g constant of PLLA having a piezoelectric tensor component d 14 = 10 pC / N is converted to g 31 , d 14 = 2 × d 31 , so that d 31 = 5 pC / N, and the piezoelectric g constant Is g 31 = 0.2258 Vm / N. Therefore, sufficient sensor sensitivity similar to PVDF can be obtained with PLLA having a piezoelectric tensor component d 14 = 10 pC / N.
　そして、本願発明の発明者は、ｄ１４＝１５～２０ｐＣ／ＮのＰＬＬＡを実験的に得ており、当該ＰＬＬＡフィルムを用いれば、非常に高感度に圧電センサ１００を構成することができる。 The inventors of the present invention have experimentally obtained PLLA with d 14 = 15 to 20 pC / N, and if the PLLA film is used, the piezoelectric sensor 100 can be configured with very high sensitivity.
　図６は、図１に示す表示装置１０の主要部の押圧力検出時の断面図である。なお、図６では、操作板１２、センサ部１６及び検出板１５が撓む様子を説明するため、これらの撓みを強調して示している。 FIG. 6 is a cross-sectional view when the pressing force of the main part of the display device 10 shown in FIG. 1 is detected. In addition, in FIG. 6, in order to demonstrate a mode that the operation board 12, the sensor part 16, and the detection board 15 bend, these bending is emphasized and shown.
　ユーザは、図６に示すように、操作板１２の操作面１０１を押圧する。これにより、圧電センサ１００のセンサ部１６及び検出板１５は、操作板１２から押し子１７を介して厚み方向に押圧され、厚み方向に撓んで圧電フィルム３１に電荷が発生する。 The user presses the operation surface 101 of the operation plate 12 as shown in FIG. As a result, the sensor unit 16 and the detection plate 15 of the piezoelectric sensor 100 are pressed in the thickness direction from the operation plate 12 via the pusher 17, and are bent in the thickness direction to generate charges in the piezoelectric film 31.
　すなわち、第１検出電極３４と第２検出電極３５との間に、押圧力の大きさ（圧電フィルム３１の伸長量）に応じた電圧値の検出電圧が、押圧力の方向に応じた電圧極性で生じる。この検出電圧は、押圧検出信号として第１端子３２及び第２端子３３を介して回路部品３９へ入力する（図３参照）。 That is, between the first detection electrode 34 and the second detection electrode 35, the detection voltage having a voltage value corresponding to the magnitude of the pressing force (the amount of expansion of the piezoelectric film 31) is a voltage polarity corresponding to the direction of the pressing force. It occurs in. This detection voltage is input to the circuit component 39 via the first terminal 32 and the second terminal 33 as a press detection signal (see FIG. 3).
　次に、圧電センサ１００の製造方法の一例について説明する。図７は、図１に示す圧電センサ１００の製造方法を示すフローチャートである。図８～図１６は、図１に示す圧電センサ１００の製造工程を示す平面図である。 Next, an example of a method for manufacturing the piezoelectric sensor 100 will be described. FIG. 7 is a flowchart showing a manufacturing method of the piezoelectric sensor 100 shown in FIG. 8 to 16 are plan views showing manufacturing steps of the piezoelectric sensor 100 shown in FIG.
　なお、実施の際は、複数個の圧電センサ１００を一括で製造するが、本実施形態では、説明を簡略化するため、１個の圧電センサ１００を製造する場面について説明する。 In the implementation, a plurality of piezoelectric sensors 100 are manufactured in a lump. However, in the present embodiment, a scene in which one piezoelectric sensor 100 is manufactured will be described in order to simplify the description.
　まず、図８に示すように、一方主面の全面に銅箔５０が貼付されたシート状のフレキシブルプリント基板３を用意する（Ｓ１）。なお、実施の際、フレキシブルプリント基板３は、センサ部３０にノイズをシールドするシールド電極層を設けるために、両主面の全面に銅箔が形成されていてもよい。 First, as shown in FIG. 8, a sheet-like flexible printed board 3 having a copper foil 50 attached to the entire surface of one main surface is prepared (S1). In the implementation, the flexible printed circuit board 3 may be formed with copper foil on the entire main surface in order to provide the sensor unit 30 with a shield electrode layer that shields noise.
　次に、図９に示すように、エッチングなどにより、フレキシブルプリント基板３の一方主面に導体パターンを形成する（Ｓ２）。これにより、第１端子３２に接続する第１検出電極３４と、第２端子３３に接続する第２検出電極３５とがフレキシブルプリント基板３の同じ面に並んで離れて形成される。 Next, as shown in FIG. 9, a conductor pattern is formed on one main surface of the flexible printed circuit board 3 by etching or the like (S2). Accordingly, the first detection electrode 34 connected to the first terminal 32 and the second detection electrode 35 connected to the second terminal 33 are formed side by side on the same surface of the flexible printed circuit board 3.
　次に、フレキシブルプリント基板３をプレス金型で打ち抜き、図１０に示す形状のフレキシブルプリント基板３０を形成する（Ｓ３）。これにより、第１端子３２、第２端子３３、スリット１８Ａ、連結部１８Ｂ、第１検出電極３４、第２検出電極３５、基板部３６及び基板部３７が形成されたフレキシブルプリント基板３０が用意される。 Next, the flexible printed circuit board 3 is punched with a press die to form the flexible printed circuit board 30 having the shape shown in FIG. 10 (S3). Thereby, the flexible printed circuit board 30 on which the first terminal 32, the second terminal 33, the slit 18A, the connecting portion 18B, the first detection electrode 34, the second detection electrode 35, the substrate portion 36, and the substrate portion 37 are formed is prepared. The
　次に、図１１に示すように、フレキシブルプリント基板３０の主要部（センサ部１６となる部分）の操作面１０１とは逆側の主面を、検出板１５の操作面１０１側の第１主面に、接着剤によって貼付する（Ｓ４）。これにより、センサ部１６となる部分は、検出板１５に接着剤によって貼付され、Ｓ７の工程の後、センサ部１６及び検出板１５の複合体が作成される。なお、この接着剤に導電性接着剤を用いて、前述のシールド電極層と接続してもよい。 Next, as shown in FIG. 11, the main surface on the side opposite to the operation surface 101 of the main portion (the portion that becomes the sensor portion 16) of the flexible printed circuit board 30 is the first main surface on the operation surface 101 side of the detection plate 15. Affixed to the surface with an adhesive (S4). Thereby, the part used as the sensor part 16 is affixed on the detection board 15 with an adhesive agent, and the composite body of the sensor part 16 and the detection board 15 is created after the process of S7. In addition, you may connect with the above-mentioned shield electrode layer using a conductive adhesive for this adhesive agent.
　次に、図３に示すように、部品実装部３８の表主面に回路部品３９を表面実装する（Ｓ５）。これにより、第１検出電極３４と第２検出電極３５とは、第１端子３２および第２端子３３を介して回路部品３９に接続される。 Next, as shown in FIG. 3, the circuit component 39 is surface-mounted on the front main surface of the component mounting portion 38 (S5). Accordingly, the first detection electrode 34 and the second detection electrode 35 are connected to the circuit component 39 via the first terminal 32 and the second terminal 33.
　次に、図１２に示すように、基板部３６の第１検出電極３４上に圧電フィルム３１を粘着剤により貼付する（Ｓ６）。この粘着剤は、導電性粘着剤であってもよい。 Next, as shown in FIG. 12, the piezoelectric film 31 is stuck on the first detection electrode 34 of the substrate portion 36 with an adhesive (S6). This pressure-sensitive adhesive may be a conductive pressure-sensitive adhesive.
　次に、図１３に示すように、基板部３７を折り返し、第２検出電極３５を圧電フィルム３１に粘着剤により貼付し、第１検出電極３４と第２検出電極３５の間に圧電フィルム３１を挟む（Ｓ７）。これにより、センサ部１６が作成され、センサ部１６及び検出板１５の複合体が完成する。この粘着剤は、導電性粘着剤であってもよい。フレキシブルプリント基板３０は、柔軟性があり大きく変形させることが可能であるため、基板部３７を折り返し易い。 Next, as shown in FIG. 13, the substrate portion 37 is folded, the second detection electrode 35 is attached to the piezoelectric film 31 with an adhesive, and the piezoelectric film 31 is interposed between the first detection electrode 34 and the second detection electrode 35. (S7). Thereby, the sensor part 16 is created and the composite body of the sensor part 16 and the detection plate 15 is completed. This pressure-sensitive adhesive may be a conductive pressure-sensitive adhesive. Since the flexible printed board 30 is flexible and can be greatly deformed, the board portion 37 is easily folded back.
　以上のＳ１～Ｓ３、Ｓ６～Ｓ７の工程により、第１検出電極３４と第２検出電極３５が形成されたフレキシブルプリント基板３０であって、第１検出電極３４と第２検出電極３５の間に圧電フィルム３１を挟んだフレキシブルプリント基板３０が用意される。 The flexible printed circuit board 30 on which the first detection electrode 34 and the second detection electrode 35 are formed by the steps S1 to S3 and S6 to S7 described above, and between the first detection electrode 34 and the second detection electrode 35. A flexible printed circuit board 30 with a piezoelectric film 31 interposed therebetween is prepared.
　次に、図１４に示すように、押し子１７を、圧電フィルム３１を挟んでいる基板部３６、３７（即ちセンサ部１６）の領域の一部における、圧電フィルム３１とは逆側の主面に、粘着剤で装着する（Ｓ８）。 Next, as shown in FIG. 14, the main surface of the pusher 17 on the side opposite to the piezoelectric film 31 in a part of the region of the substrate portions 36 and 37 (that is, the sensor portion 16) sandwiching the piezoelectric film 31. (S8).
　次に、図１５に示すように、検出板１５の操作面１０１とは逆側の第２主面に垂直な方向から見て、クッション２１を、検出板１５の第２主面における押し子１７と重なる領域に装着する（Ｓ９）。 Next, as shown in FIG. 15, when viewed from the direction perpendicular to the second main surface opposite to the operation surface 101 of the detection plate 15, the cushion 21 is pushed by the pusher 17 on the second main surface of the detection plate 15. (S9).
　次に、図１６に示すように、スペーサ１４Ａ及びスペーサ１４Ｂを、検出板１５の両端部の両面に装着する（Ｓ１０）。 Next, as shown in FIG. 16, spacers 14A and 14B are mounted on both surfaces of both ends of the detection plate 15 (S10).
　以上のような工程を経て本実施形態の圧電センサ１００は製造することができる。 The piezoelectric sensor 100 of the present embodiment can be manufactured through the above-described steps.
　最後に、センサ部１６及び検出板１５の複合体を備える圧電センサ１００をオートクレーブで加熱処理する（Ｓ１１）。この熱処理工程は、圧電センサ１００を、７０℃以上１００℃以下の温度で、少なくとも０．５時間以上、加熱処理することが好ましく、更には３時間以上加熱処理することがより好ましい。
　なお、加熱温度の最大値は圧電フィルムの耐熱性によって設定され、本件の場合は１００℃以下が好適である。 Finally, the piezoelectric sensor 100 including the composite body of the sensor unit 16 and the detection plate 15 is heat-treated with an autoclave (S11). In this heat treatment step, the piezoelectric sensor 100 is preferably heat-treated at a temperature of 70 ° C. or higher and 100 ° C. or lower for at least 0.5 hours, and more preferably 3 hours or longer.
The maximum value of the heating temperature is set according to the heat resistance of the piezoelectric film, and in this case, 100 ° C. or less is suitable.
　なお、熱処理工程は、圧電センサ１００を、大気圧より高い圧力の雰囲気下で加熱処理することで、加熱時間を短縮することができる。発明者は、大気圧の場合は加熱温度９０℃で１２０分かかっていたものが、気圧を１０気圧にすると、同じ加熱温度であっても５０分にまで短縮できることを確認した。 In the heat treatment step, the heating time can be shortened by heat-treating the piezoelectric sensor 100 in an atmosphere at a pressure higher than atmospheric pressure. The inventor has confirmed that in the case of atmospheric pressure, which took 120 minutes at a heating temperature of 90 ° C., the pressure can be reduced to 50 minutes even at the same heating temperature if the atmospheric pressure is 10 atmospheres.
　上記Ｓ１１の熱処理工程では、センサ部１６及び検出板１５の複合体に対して加熱処理を行うため、熱エージング特性に優れた複合体を得ることができる。 In the heat treatment step of S11, since the heat treatment is performed on the composite of the sensor unit 16 and the detection plate 15, a composite having excellent thermal aging characteristics can be obtained.
　よって、この製造方法で製造された圧電センサ１００が温度変化のある環境下で使用されても、検出板１５が押圧され、圧電フィルム３１が撓むことによって生じる圧電センサ１００の出力電圧が、圧電センサ１００の個体毎に大きくバラつくことを抑制できる。 Therefore, even when the piezoelectric sensor 100 manufactured by this manufacturing method is used in an environment with a temperature change, the output voltage of the piezoelectric sensor 100 generated when the detection plate 15 is pressed and the piezoelectric film 31 is bent becomes piezoelectric. It is possible to suppress a large variation for each individual sensor 100.
　したがって、この製造方法によれば、温度変化に対する圧電センサ１００の出力電圧のバラつきを抑えることができる。 Therefore, according to this manufacturing method, variations in the output voltage of the piezoelectric sensor 100 with respect to temperature changes can be suppressed.
　以下、加熱処理工程を経ていない圧電センサ１００に対してヒートサイクル試験を行った結果と、加熱処理工程を経た圧電センサ１００に対してヒートサイクル試験を行った結果とを比較する。 Hereinafter, the result of the heat cycle test performed on the piezoelectric sensor 100 that has not undergone the heat treatment process and the result of the heat cycle test performed on the piezoelectric sensor 100 that has undergone the heat treatment process will be compared.
　図１７は、加熱処理工程を経ていない圧電センサ１００と加熱処理工程を経た圧電センサ１００とにおける、ヒートサイクルの回数と出力電圧との関係を示す図である。図１７は、加熱処理工程を経ていない圧電センサ１００と加熱処理工程を経た圧電センサ１００とを２つずつ用意し、４つの圧電センサ１００を－４０度の低温環境下に３０分さらした後に+８５度の高温環境下に３０分さらすヒートサイクルを複数回繰り返した条件で、４つの圧電センサ１００の出力電圧を測定した実験結果を示している。
　図１７のうち、Ｎｏ．１、Ｎｏ．２は加熱処理工程を経ていない圧電センサ１００とし、Ｎｏ．３、Ｎｏ．４は加熱処理工程を経た圧電センサである。 FIG. 17 is a diagram illustrating the relationship between the number of heat cycles and the output voltage in the piezoelectric sensor 100 that has not undergone the heat treatment process and the piezoelectric sensor 100 that has undergone the heat treatment process. FIG. 17 shows that two piezoelectric sensors 100 that have not undergone a heat treatment process and two piezoelectric sensors 100 that have undergone a heat treatment process are prepared, and after four piezoelectric sensors 100 are exposed to a low temperature environment of −40 degrees for 30 minutes. The experimental result which measured the output voltage of the four piezoelectric sensors 100 on the conditions which repeated the heat cycle exposed to a high temperature environment of 85 degree | times for 30 minutes is shown.
In FIG. 1, no. 2 is the piezoelectric sensor 100 that has not undergone the heat treatment process. 3, no. Reference numeral 4 denotes a piezoelectric sensor that has undergone a heat treatment process.
　実験により、加熱処理工程を経ていない圧電センサ１００（図１７のＮｏ．１、Ｎｏ．２）では、検出板１５が押圧された時に生じる圧電センサ１００の出力電圧が、圧電センサ１００の個体毎に大きくバラついていたのに対して、加熱処理工程を経た圧電センサ１００（図１７のＮｏ．３、Ｎｏ．４）では、検出板１５が押圧された時に生じる圧電センサ１００の出力電圧が、圧電センサ１００の個体毎に大きくバラつくことを抑制できていることが明らかとなった。 According to experiments, in the piezoelectric sensors 100 (No. 1 and No. 2 in FIG. 17) that have not undergone the heat treatment process, the output voltage of the piezoelectric sensor 100 generated when the detection plate 15 is pressed is different for each individual piezoelectric sensor 100. In contrast to the large variation, in the piezoelectric sensor 100 (No. 3 and No. 4 in FIG. 17) after the heat treatment process, the output voltage of the piezoelectric sensor 100 generated when the detection plate 15 is pressed is the piezoelectric sensor. It became clear that it was possible to suppress large variations for every 100 individuals.
　したがって、この製造方法によれば、温度変化に対する圧電センサ１００の出力電圧のバラつきを抑えることができる。 Therefore, according to this manufacturing method, variations in the output voltage of the piezoelectric sensor 100 with respect to temperature changes can be suppressed.
　なお、前記実施形態では、圧電フィルム３１の平面形状は長方形状であるが、これに限るものではない。実施の際、圧電フィルムの平面形状は、正方形状、円形状、台形状、平行四辺形状、四角形以上の多角形状、楕円形状、長円形状等、他の平面形状であってもよい。 In addition, in the said embodiment, although the planar shape of the piezoelectric film 31 is a rectangular shape, it is not restricted to this. In implementation, the planar shape of the piezoelectric film may be other planar shapes such as a square shape, a circular shape, a trapezoidal shape, a parallelogram shape, a polygonal shape of quadrilateral or more, an elliptical shape, an oval shape, or the like.
　また、前記実施形態において検出板１５の材料は、ＳＵＳ（ステンレススチール）であるが、これに限るものではない。実施の際は、検出板１５の材料は、例えばガラス板でもよい。 In the above embodiment, the material of the detection plate 15 is SUS (stainless steel), but is not limited thereto. In implementation, the material of the detection plate 15 may be a glass plate, for example.
　また、前記実施形態において圧電センサ１００は、押し子１７、クッション２１、スペーサ１４Ａ、及びスペーサ１４Ｂを有するが、これに限るものではない。実施の際は、圧電センサ１００が、押し子１７、クッション２１、スペーサ１４Ａ、及びスペーサ１４Ｂを有していなくてもよい。例えば、前記実施形態において押し子１７は、操作板１２とセンサ部１６との間に配置されているが、これに限るものではない。実施の際は、押し子１７、スペーサ１４Ａ、及びスペーサ１４Ｂを配置せず、操作板１２とセンサ部１６とが直接貼付されていてもよい。 In the embodiment, the piezoelectric sensor 100 includes the pusher 17, the cushion 21, the spacer 14A, and the spacer 14B, but is not limited thereto. In implementation, the piezoelectric sensor 100 may not include the pusher 17, the cushion 21, the spacer 14A, and the spacer 14B. For example, in the embodiment, the pusher 17 is disposed between the operation plate 12 and the sensor unit 16, but is not limited thereto. At the time of implementation, the operation plate 12 and the sensor unit 16 may be directly attached without arranging the pusher 17, the spacer 14A, and the spacer 14B.
　最後に、前記各実施形態の説明は、すべての点で例示であって、制限的なものではないと考えられるべきである。本発明の範囲は、上述の実施形態ではなく、特許請求の範囲によって示される。さらに、本発明の範囲には、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 Finally, the description of each of the embodiments should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.
３…フレキシブルプリント基板
１０…表示装置
１１…筐体
１２…操作板
１４Ａ，１４Ｂ…スペーサ
１５…検出板
１６…センサ部
１７…押し子
１８Ａ…スリット
１８Ｂ…連結部
２１…クッション
３０…フレキシブルプリント基板
３１…圧電フィルム
３２…第１端子
３３…第２端子
３４…第１検出電極
３５…第２検出電極
３６，３７…基板部
３８…部品実装部
３９…回路部品
５０…銅箔
９０…粘着剤層
９１，９２…導電性粘着剤層
１００…圧電センサ
１０１…操作面 DESCRIPTION OF SYMBOLS 3 ... Flexible printed circuit board 10 ... Display apparatus 11 ... Housing | casing 12 ... Operation board 14A, 14B ... Spacer 15 ... Detection board 16 ... Sensor part 17 ... Pusher 18A ... Slit 18B ... Connection part 21 ... Cushion 30 ... Flexible printed circuit board 31 ... piezoelectric film 32 ... first terminal 33 ... second terminal 34 ... first detection electrode 35 ... second detection electrodes 36, 37 ... substrate part 38 ... component mounting part 39 ... circuit component 50 ... copper foil 90 ... adhesive layer 91 , 92 ... conductive adhesive layer 100 ... piezoelectric sensor 101 ... operation surface

Claims (10)

  1. 　第１検出電極および第２検出電極が形成された基板部であって、前記第１検出電極と第２検出電極の間に圧電フィルムを挟んだ基板部を備える圧電センサの製造方法であって、
    　前記基板部の前記圧電フィルムとは逆側の主面と、押圧されることによって厚み方向に撓む検出板の主面と、を粘着剤によって貼付し、前記基板部及び前記検出板の複合体を作成する作成工程と、
    　前記複合体を加熱処理する熱処理工程と、
    　を含む、圧電センサの製造方法。     A method of manufacturing a piezoelectric sensor comprising a substrate portion on which a first detection electrode and a second detection electrode are formed, wherein the substrate portion sandwiches a piezoelectric film between the first detection electrode and the second detection electrode,
    The main surface of the substrate portion opposite to the piezoelectric film and the main surface of the detection plate that bends in the thickness direction when pressed are adhered with an adhesive, and the composite of the substrate portion and the detection plate Creating process to create
    A heat treatment step for heat-treating the composite;
    A method for manufacturing a piezoelectric sensor, comprising:
  2. 　前記第１検出電極および前記第２検出電極を前記基板部の同じ面に並んで離れて形成する電極形成工程と、
    　前記基板部の前記第１検出電極上に圧電フィルムを貼付する第１貼付工程と、
    　前記基板部を折り返し、前記第２検出電極を前記圧電フィルムに貼付し、前記第１検出電極と第２検出電極の間に前記圧電フィルムを挟む第２貼付工程と、
    　を含む、請求項１に記載の圧電センサの製造方法。     An electrode forming step of forming the first detection electrode and the second detection electrode side by side on the same surface of the substrate portion; and
    A first pasting step of pasting a piezoelectric film on the first detection electrode of the substrate portion;
    A second attaching step of folding the substrate portion, attaching the second detection electrode to the piezoelectric film, and sandwiching the piezoelectric film between the first detection electrode and the second detection electrode;
    The manufacturing method of the piezoelectric sensor of Claim 1 containing this.
  3. 　前記熱処理工程は、前記複合体を、７０℃以上１００℃以下の温度で加熱処理する、
    　を含む、請求項１又は２に記載の圧電センサの製造方法。     In the heat treatment step, the composite is heat-treated at a temperature of 70 ° C. or higher and 100 ° C. or lower.
    The manufacturing method of the piezoelectric sensor of Claim 1 or 2 containing this.
  4. 　前記熱処理工程は、前記複合体を、大気圧より高い圧力の雰囲気下で加熱処理する、
    　請求項１から請求項３のいずれか１項に記載の圧電センサの製造方法。     In the heat treatment step, the composite is heat-treated in an atmosphere at a pressure higher than atmospheric pressure.
    The manufacturing method of the piezoelectric sensor of any one of Claims 1-3.
  5. 　前記熱処理工程は、前記複合体を、０．５時間以上、加熱処理する、
    　請求項１から請求項３のいずれか１項に記載の圧電センサの製造方法。     The heat treatment step heat-treats the composite for 0.5 hour or more.
    The manufacturing method of the piezoelectric sensor of any one of Claims 1-3.
  6. 　前記粘着剤は、アクリル系粘着剤である、請求項１から請求項５のいずれか１項に記載の圧電センサの製造方法。 The method for manufacturing a piezoelectric sensor according to claim 1, wherein the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive.
  7. 　前記検出板の材料は、ガラスまたはステンレススチールである、請求項１から請求項６のいずれか１項に記載の圧電センサの製造方法。 The method for manufacturing a piezoelectric sensor according to any one of claims 1 to 6, wherein a material of the detection plate is glass or stainless steel.
  8. 　前記圧電フィルムは、キラル高分子によって形成されている、請求項１から請求項７のいずれか１項に記載の圧電センサの製造方法。 The method for manufacturing a piezoelectric sensor according to any one of claims 1 to 7, wherein the piezoelectric film is formed of a chiral polymer.
  9. 　前記キラル高分子は、ポリ乳酸である、請求項８に記載の圧電センサの製造方法。 The method for manufacturing a piezoelectric sensor according to claim 8, wherein the chiral polymer is polylactic acid.
  10. 　前記ポリ乳酸は、Ｌ型ポリ乳酸である、請求項９に記載の圧電センサの製造方法。 The method for manufacturing a piezoelectric sensor according to claim 9, wherein the polylactic acid is L-type polylactic acid.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112903147A (en) * 2021-02-01 2021-06-04 河北工业大学 Continuous monitoring flexible pressure sensor and composite film layer production method
CN115448586A (en) * 2022-10-27 2022-12-09 芜湖东信光电科技有限公司 Foldable glass and preparation method thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001320101A (en) * 1999-10-01 2001-11-16 Ngk Insulators Ltd Piezoelectric/electrostrictive device and its manufacturing method
JP2009053109A (en) * 2007-08-28 2009-03-12 Aisin Seiki Co Ltd Piezoelectric film sensor
JP2011221721A (en) * 2010-04-07 2011-11-04 Daikin Ind Ltd Transparent piezoelectric sheet with frame each including transparent piezoelectric sheet, touch panel and electronic device
WO2012137897A1 (en) * 2011-04-08 2012-10-11 株式会社村田製作所 Displacement sensor, displacement detecting apparatus, and operation device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0726222A (en) * 1993-07-13 1995-01-27 Sekisui Chem Co Ltd Production of self-adhesive tape
JP2011133421A (en) * 2009-12-25 2011-07-07 Nissha Printing Co Ltd Pressure sensitive sensor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001320101A (en) * 1999-10-01 2001-11-16 Ngk Insulators Ltd Piezoelectric/electrostrictive device and its manufacturing method
JP2009053109A (en) * 2007-08-28 2009-03-12 Aisin Seiki Co Ltd Piezoelectric film sensor
JP2011221721A (en) * 2010-04-07 2011-11-04 Daikin Ind Ltd Transparent piezoelectric sheet with frame each including transparent piezoelectric sheet, touch panel and electronic device
WO2012137897A1 (en) * 2011-04-08 2012-10-11 株式会社村田製作所 Displacement sensor, displacement detecting apparatus, and operation device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112903147A (en) * 2021-02-01 2021-06-04 河北工业大学 Continuous monitoring flexible pressure sensor and composite film layer production method
CN115448586A (en) * 2022-10-27 2022-12-09 芜湖东信光电科技有限公司 Foldable glass and preparation method thereof

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