WO2014196360A1

WO2014196360A1 - Piezoelectric sensor and electronic device

Info

Publication number: WO2014196360A1
Application number: PCT/JP2014/063468
Authority: WO
Inventors: 裕次渡津; 喜子末▲富▼; 栄二角谷; 啓佑尾▲崎▼; 柴田　淳一; 勝己 ▲徳▼野; 奥村　秀三; 面　了明
Original assignee: 日本写真印刷株式会社
Priority date: 2013-06-04
Filing date: 2014-05-21
Publication date: 2014-12-11

Abstract

[Problem] To provide a piezoelectric sensor in which position detection and load detection can be carried out within the sensor. [Solution] This piezoelectric sensor (10) is provided with a piezoelectric layer (13), a first electrode (11) laminated on a first main surface of the piezoelectric layer (13), a second electrode (12) laminated on the first main surface of the piezoelectric layer (13) with the first electrode (11), a reference electrode (14) laminated on a second main surface of the piezoelectric layer (13) that is on the opposite side from the first main surface, and this piezoelectric sensor is such that the first electrode is provided with a plurality of first unit electrodes that extend from a first side of the piezoelectric layer (13) to a second side opposite from the first side and have widths that become smaller as the first unit electrodes approach the second side, the second electrode is provided with a plurality of second unit electrodes that extend in the same direction as the first unit electrodes and have widths that become smaller as the second unit electrodes approach the first side, and the first unit electrodes and second unit electrodes are configured so as to engage in a planar view.

Description

Piezoelectric sensor and electronic device

The present invention relates to a piezoelectric sensor that generates a piezoelectric signal corresponding to a load, and more particularly to a piezoelectric sensor that can detect a position where a load is applied.

A piezoelectric sensor using a piezoelectric layer is known to detect a given load. For example, Patent Document 1 discloses a transparent piezoelectric sensor including a transparent pressure-sensitive layer and a pair of transparent conductive layers.

JP 2004-125571 A

However, the transparent piezoelectric sensor of Patent Document 1 can detect a given load, but cannot detect the position in the transparent piezoelectric sensor.

In order to achieve the above object, the present invention is configured as follows.

The piezoelectric sensor according to the present invention includes a piezoelectric layer, a first electrode and a second electrode portion stacked on the first main surface of the piezoelectric layer, and a second main surface opposite to the first main surface of the piezoelectric layer. And a reference electrode. The first electrode unit is composed of a plurality of first unit electrodes arranged at intervals. The first unit electrode extends from the first side to the second side opposite to the first side, and decreases in size in the width direction as it approaches the second side.
The second electrode portion is composed of a plurality of second unit electrodes arranged at intervals. The second unit electrode extends in the same direction as the first electrode, and decreases in size in the width direction as it approaches the first side. The second unit electrode is arranged so as to mesh with the first unit electrode in plan view.

Then, as the piezoelectric sensor approaches the first side, the proportion of the first unit electrode increases, and conversely, the proportion of the second unit electrode increases as it approaches the second side. Therefore, when the load is applied to the piezoelectric sensor and the charge is generated, the load amount is detected at the position where the load is applied by calculating the ratio between the unit electrode position where the charge is detected and the charge amount. Is possible.

The pitch length of the first unit electrode and the second unit electrode is designed to be shorter than the length of the short diameter of the contact surface formed between the input unit and the piezoelectric sensor when the input unit contacts the piezoelectric sensor. It may be.

Then, when the input means comes into contact with the piezoelectric sensor, the input means comes into contact with at least the first unit electrode and the second unit electrode. As a result, the number of places where the input means can be detected increases, so that more accurate position detection is possible.

The pitch length of the first unit electrode and the pitch length of the second unit electrode may be 1 mm to 16 mm.

Then, when the finger contacts the piezoelectric sensor, the finger contacts the first unit electrode and the second unit electrode. As a result, accurate position detection is possible.

The piezoelectric layer may be composed of an active piezoelectric portion and an inactive piezoelectric portion, and a first electrode and a second electrode may be laminated on the active piezoelectric portion.

Then, the occurrence of the crosstalk phenomenon can be prevented. As a result, the detection accuracy of the position applied to the piezoelectric sensor and the load is improved.

The first electrode may be provided on the first main surface side of the piezoelectric sensor, and the second electrode may be provided on the second main surface side of the piezoelectric sensor.

Then, since the first electrode and the second electrode are provided via the piezoelectric layer, the crosstalk phenomenon that occurs between the first electrode and the second electrode is reduced. As a result, the accuracy of position detection and load detection is improved.

The upper electrode may contain indium tin oxide or polyethyldioxothiophene.

Then, since the transparency of the upper electrode is increased, a piezoelectric sensor can be disposed on a display device such as a liquid crystal or an organic EL.

The lower electrode may contain indium tin oxide or polyethyldioxothiophene.

Then, since the transparency of the lower electrode is increased, the piezoelectric sensor can be disposed on a display device such as a liquid crystal or an organic EL.

The piezoelectric layer may be composed of an organic piezoelectric material.

Then, since the flexibility of the piezoelectric layer is increased, the bending resistance of the piezoelectric sensor is improved. As a result, the piezoelectric sensor can be arranged on an R curved surface.

The organic piezoelectric material may contain polyvinylidene fluoride or polylactic acid.

Then, since the transparency of the piezoelectric layer is increased, the piezoelectric sensor can be disposed on a display device such as a liquid crystal or an organic EL.

The piezoelectric layer may be made of an inorganic material.

Then, since the piezoelectric constant of the piezoelectric layer is increased, the detection sensitivity for detecting force is improved.

The pressure detection device may include a piezoelectric sensor and a touch panel.

In that case, the load position can be detected even when the load is hardly applied to the piezoelectric sensor.

The capacitive touch panel may be a capacitive touch panel. If it does so, the transparency of the whole pressure detection apparatus will improve.

In the piezoelectric sensor according to the present invention, position detection can be performed within the piezoelectric sensor.

It is a conceptual diagram of a pressure detection apparatus. FIG. 2 is a cross-sectional view taken along line A-A ′ of FIG. 1. It is the flowchart which showed the process which detects a position and a load. It is a top view of a piezoelectric sensor. It is a top view of a piezoelectric sensor. FIG. 6 is a B-B ′ sectional view of FIG. 5. It is a top view of a piezoelectric sensor. It is sectional drawing of a piezoelectric sensor. It is sectional drawing of the pressure detection apparatus which combined the piezoelectric sensor and the electrostatic touch panel. It is a top view of a piezoelectric sensor. It is a top view of a piezoelectric sensor.

Hereinafter, embodiments according to the present invention will be described in more detail with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative positions, etc. of the parts and portions described in the embodiments of the present invention are not intended to limit the scope of the present invention only to those unless otherwise specified. This is just an illustrative example.

1. First Embodiment (1) Overall Structure of Pressure Detection Device The overall structure of a pressure detection device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view of a pressure detection device. FIG. 2 is a sectional view of the piezoelectric sensor. FIG. 3 is a diagram showing a contact portion between the piezoelectric sensor and the finger when the piezoelectric sensor comes into contact with the finger.

The pressure detection device has a function of detecting the amount and position of a given load.
As shown in FIG. 1, the pressure detection device 1 includes a piezoelectric sensor 10, a detection unit 20, and a control unit 30. The piezoelectric sensor 10 is a device that generates an electric charge according to a given load. The detection unit 20 includes a first detection unit 21 and a second detection unit 22, and the control unit 30 includes a first control unit 31 and a second control unit 32. The first detection unit 21 and the second detection unit 22 are devices that detect charges generated by the piezoelectric sensor 10. The first control unit 31 is a device that controls the switch S installed in the piezoelectric sensor 10 and the first detection unit 21, and the second control unit 32 is a switch installed in the piezoelectric sensor 10 and the second detection unit 22. It is a device for controlling S ′. Below, the structure of the pressure detection apparatus 1 is demonstrated in detail.

(2) Piezoelectric Sensor As shown in FIGS. 1 and 2, the piezoelectric sensor 10 includes a first electrode 11, a second electrode 12, a piezoelectric layer 13, a reference electrode 14, a substrate 15, and an adhesive 16. Composed. The first electrode 11 includes

first unit electrodes

11a, 11b,... 11e. The second electrode 12 includes

second unit electrodes

12a, 12b,. The reference electrode 14 is a pattern that covers the first electrode 11 and the second electrode 12, and fixes the potential to the reference potential (GND) when detecting the charge.

The

first unit electrodes

11a, 11b,... 11e are composed of isosceles triangles having a first side of the piezoelectric layer 13 as a base and a second side opposite to the first side as a vertex. . The

first unit electrodes

11a, 11b,... 11e each have a base length of L, and are arranged with an interval D in the Y-axis direction.

The

second unit electrodes

12a, 12b,... 12e are composed of isosceles triangles having the second side as the base, the first side as the apex, and the base length being l in the piezoelectric layer 13. Yes. In addition, the

second unit electrodes

12a, 12b,... 12e are arranged in the Y-axis direction with an interval d so as to mesh with the

first unit electrodes

11a, 11b,.

The length L of the bottom of the first unit electrode and the total length of the distance D (the pitch length of the first electrode 11) are the same as the piezoelectric sensor 10 and the input means when the input means such as a finger contacts the piezoelectric sensor 10. Is preferably set to be shorter than the length of the minor axis of the contact surface formed therebetween.

When configured as described above, the number of contacts between the input means and the

first unit electrodes

11a, 11b,. As a result, the detection function of the piezoelectric sensor 10 is improved.

Note that the length l of the bottom of the second unit electrode and the total length of the distance d (pitch length of the second electrode 12) are also measured when the input means such as a finger and the piezoelectric sensor 10 come into contact with each other. It is preferable that the length of the short diameter of the contact surface formed between the input means and the input means is set to be shorter.

second unit electrodes

12a, 12b,. As a result, the detection function of the piezoelectric sensor 10 is improved.

In the above description, the input means refers to, for example, a finger or a stylus pen. When the input means is a finger, the pitch length of the first electrode 11 and the pitch length of the second electrode 12 are 1 mm to 16 mm. 0.5 mm to 4 mm.

(3) Electrode The 1st electrode 11, the 2nd electrode 12, and the reference electrode 14 can be comprised with the material which has electroconductivity. Examples of the conductive material include transparent conductive oxides such as indium-tin oxide (ITO), tin-zinc oxide (Tin), polyethylene dioxythiophene A conductive polymer such as (Polyethylenedioxythiophene, PEDOT) can be used. In this case, the electrode can be formed by using vapor deposition or screen printing.

Also, a conductive metal such as copper or silver may be used as the conductive material. In this case, the electrode may be formed by vapor deposition, or may be formed using a metal paste such as a copper paste or a silver paste.

Furthermore, a conductive material in which conductive materials such as carbon nanotubes, metal particles, and metal nanofibers are dispersed may be used as the conductive material.
(4) Piezoelectric layer Examples of the material constituting the piezoelectric layer 13 include inorganic piezoelectric materials and organic piezoelectric materials.

Examples of inorganic piezoelectric materials include barium titanate, lead titanate, lead zirconate titanate, potassium niobate, lithium niobate, and lithium tantalate.

Examples of the organic piezoelectric material include a fluoride polymer or a copolymer thereof, and a polymer material having chirality. Examples of the fluoride polymer or a copolymer thereof include polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, and vinylidene fluoride-trifluoroethylene copolymer. Examples of the polymer material having chirality include L-type polylactic acid and R-type polylactic acid.

When the pressure detection device 1 is arranged on a display device such as a liquid crystal device or an organic EL device, the piezoelectric layer is made of a transparent material so that the display of the display device can be seen, or It is preferable that the thickness be thin enough to transmit light sufficiently.

(5) Substrate The substrate 15 is a protective member that protects the piezoelectric sensor 10. From the viewpoint of protecting the piezoelectric sensor 10, the substrate 15 is preferably composed of a member having a hardness of 2H or higher. As a material constituting the substrate 15, an inorganic material, an organic material, or an inorganic-organic hybrid material can be used.

As the inorganic material, a glass plate or the like can be used. As the organic material, resin materials such as polycarbonate, acrylic, and polyethylene terephthalate can be used. As the inorganic-organic hybrid material, a resin material in which a fiber material such as glass fiber is kneaded can be used. A hard coat material may be laminated on the substrate 10.

(6) Detection Unit As shown in FIG. 1, the first electrode 11 (first unit electrodes 11a to 11e) is connected to the first detection unit 21. The second electrode 12 (second unit electrodes 12a to 12e) is connected to the second detection unit 22. The reference electrode 14 is connected to ground. When configured as described above, the first detection unit 21 can detect the electric charge generated between the first electrode 11 and the reference electrode 40 when the piezoelectric layer 13 is pressed. The charge generated between the second electrode 12 and the reference electrode 40 can be detected by the second detector 22. In addition, the 1st detection part 21 and the 2nd detection part 22 can use the detection apparatus provided with amplifier and AD converter.

(7) Control Unit The first control unit 31 is connected to the switch S that connects the first electrode 11 and the first detection unit 21. The second control unit 32 is connected to a switch S ′ that connects the second electrode 11 and the second detection unit 22. The 1st control part 31 and the 2nd control part 32 are provided with the function which can output the switching signal of ON-OFF about switch S and switch S ', respectively.

The 1st control part 31 and the 2nd control part 32 can be included in the drive system of pressure detector 1, for example. The drive system may be a microcomputer including a CPU (Central Processing Unit), a storage unit, and an interface for driving a piezoelectric sensor. Alternatively, the drive system may be integrated into one IC by a custom IC or the like.

Further, the above functions of the control unit may be realized by causing a CPU or a custom IC to execute a program stored in a storage unit such as the microcomputer or the custom IC.

As described above, when the pressure detection device 1 is configured, the charge generated in the piezoelectric layer 13 disposed under the first electrode 11 can be detected by the first detection unit 20 and is disposed under the second electrode 12. The charge generated in the piezoelectric layer 13 can be detected by the second detection unit 21. Then, it is possible to detect the position and amount of the load from the detected charge. A method for detecting the position and amount of the load will be described below.

As shown in FIG. 3, the detection of the position and amount where the load is applied is achieved through the steps 1 to 5.

1) STEP1:
<Applying load to the piezoelectric sensor>
As shown in FIGS. 3 and 4, in STEP 1, a load is applied to the region A of the piezoelectric sensor 10 by the finger. Then, an electric charge is generated on the unit electrode arranged in the region A, that is, on the piezoelectric layer 13 arranged below the first unit electrode 11b, the second unit electrode 12b, and the second unit electrode 12c.

2) STEP2:
<Charge detection in the first detection unit>
In STEP 2, among the electrodes, the charge generated on the first unit electrode 11 b is detected by the first detection unit 21. At this time, the first detection unit 21 stores the information on the detected charge and the charge amount. In the case of FIG. 4, the charge Q1 passes through the first unit electrode 11b, and the charge amount q1 of the charge Q1 is stored in the first detection unit 21.

3) STEP3:
<Charge detection in the second detection unit>
In STEP 3, the charges Q2 and Q3 generated on the second unit electrode 12b and the second unit electrode 12c are detected by the second detector. At this time, the route information of the charge Q2 and the charge Q3 and the charge amounts q2 and q3 are stored in the second detection unit. In the above case, the charge Q2 is stored through the second unit electrode 12b and the charge amount q2. For the charge Q3, the fact that it has passed through the second unit electrode 12c and the charge amount q3 are stored.

4) STEP4:
<Specification of Y direction>
In STEP 4, the component in the Y-axis direction at the position where the load is applied is specified. For specifying the component, the route information stored in STEP2 and STEP3 is used. In the case of FIG. 4, it is used that the charge Q1 passes through the first unit electrode 11b, and that the charge Q2 and the charge Q3 pass through the second unit electrode 12b and the second unit electrode 12c, respectively. From these pieces of information, it is specified that the component in the Y-axis direction at the position where the load is applied extends from the second unit electrode 12b to the region of the second unit electrode 12c.

5) STEP5:
<Specification of X direction>
In STEP5, the ratio between the charge amount q1 detected in STEP2 and the charge amounts q2 and q3 detected in STEP3 is calculated. As shown in FIG. 4, as the piezoelectric sensor 10 moves toward the first side, the contact between the finger and the first unit electrode increases. On the other hand, the contact between the finger and the second unit electrode becomes larger as going to the second side.
That is, the closer the contact between the piezoelectric sensor and the finger is to the first side (left side), the more charge is detected from the first unit electrode, and the contact between the piezoelectric sensor and the finger is on the second side. The amount of charge detected from the second unit electrode increases as the value is (right side). From this, the position in the X direction can be specified by comparing the charge amounts detected by the first detector 21 and the second detector 22. In STEP5, the charge amount q1 detected in STEP2 is compared with the charge amounts q2 and q3 detected in STEP3 to identify the component in the X-axis direction at the position where the load is applied.

6) STEP6:
<Identification of load position>
In STEP 6, the position information in the X direction and Y direction specified in STEP 4 and STEP 5 is combined. As a result, the position where the load is applied can be specified.

7) STEP7:
<Specification of load amount>
In STEP 7, the sum of the charge amount q1 stored in STEP 2 and the charge amounts q2 and q3 stored in STEP 3 is obtained. Thereby, the load amount given to the piezoelectric sensor 10 can be specified. In the case of FIG. 4, the amount of load applied to the piezoelectric sensor 10 can be specified by obtaining the total value of the charge amount q1 and the charge amount q2 and the charge amount q3.

The configuration as described above makes it possible to detect a given load and load amount. It should be noted that the same process can be used when a plurality of places are loaded. That is, the pressure detection device 1 can perform multi-force detection.

In the above description, the first unit electrodes 11a to 11e and the first detection unit 21 are connected via the switch S. However, if fine position detection in the Y-axis direction is unnecessary, the first unit electrodes 11a to 11e may be short-circuited to connect the first unit electrodes 11a to 11e and the first detection unit 21. With this configuration, the switch S and the first control unit 31 are not necessary, and thus the overall configuration of the pressure detection device 1 can be simplified.

If position detection in the Y-axis direction is not required at all, the second unit electrodes 12a to 12e may be short-circuited to connect the second unit electrodes 12a to 12e and the second detection unit 22. With this configuration, the switch S ′ and the second control unit 32 are unnecessary, so that the overall configuration of the pressure detection device 1 can be further simplified.

2. Second Embodiment In the first embodiment, the first electrode and the second electrode are arranged on one side of the piezoelectric layer. However, the first electrode may be disposed on one surface side of the piezoelectric layer, and the second electrode may be disposed on the other surface side.

FIG. 5 is a plan view of the piezoelectric sensor according to the second embodiment. 6 is a cross-sectional view taken along the line B-B 'of FIG.

As shown in FIG. 5, the piezoelectric sensor 10 according to the second embodiment includes a first electrode 11, a second electrode 12,

piezoelectric layers

13 a and 13 b, and a reference electrode 14. The first electrode 11 includes a plurality of first unit electrodes 11a to 11e, and the second electrode 12 includes a plurality of second unit electrodes 12a to 12e. In the first embodiment, the second electrode 12 is arranged on a surface different from the surface on which the first electrode 11 is laminated, and the first piezoelectric layer 13a in which the piezoelectric layer is in contact with the first electrode 11; The second piezoelectric layer 13b is in contact with the second electrode 12, and the reference electrode 14 is disposed between the first piezoelectric layer 13a and the second piezoelectric layer 13b.

In addition, the 1st electrode 11 and the 2nd electrode 12 may be arrange | positioned so that the peripheral part may overlap through a piezoelectric layer. If comprised as mentioned above, in addition to the area | region where only the 1st electrode 11 was laminated | stacked and the area | region where only the 2nd electrode 12 was laminated | stacked, the area | region where the 1st electrode 11 and the 2nd electrode 12 were laminated | stacked Made. As a result, since the number of detection types increases, the function of the piezoelectric sensor 10 is improved.

3. Third Embodiment FIG. 7 is a plan view of a piezoelectric sensor according to a third embodiment.

In the first and second embodiments, the first unit electrodes 11a to 11e and the second unit electrodes 12a to 12e are isosceles triangles. However, the pattern of the first unit electrodes 11a to 11e extends from the first side of the piezoelectric layer 13 to the second side on the opposite side, and becomes smaller as the size in the width direction approaches the second side. If the pattern of the two unit electrodes 12a to 12e extends in the same direction as the first unit electrodes 11a to 11e and is formed so that the size in the width direction becomes smaller as it approaches the first side, It is not limited to equilateral triangles. For example, as shown in FIG. 7, the first unit electrodes 11a to 11e may be right triangles having a base on the first side and a vertex on the second side. The second unit electrodes 12a to 12e may also be right triangles having a base on the second side and a vertex on the first side.

Further, as shown in FIG. 10, the first unit electrodes 11a to 11e may be trapezoids having a base on the first side and an upper side on the second side. The second unit electrodes 12a to 12e may also be trapezoids having a bottom side on the second side and an upper side on the first side.

In addition, as shown in FIG. 11, two or more adjacent ones of the first unit electrodes 11a to 11e may be coupled on the first side. As for the second unit electrodes 12a to 12e, two or more adjacent ones may be coupled on the second side.

4). Fourth Embodiment The piezoelectric layer 13 may include an active piezoelectric portion 130 and an inactive piezoelectric portion 131.

FIG. 8 is a cross-sectional view of the piezoelectric sensor according to the fourth embodiment.

As shown in FIG. 8, the piezoelectric layer 13 may be composed of an active piezoelectric portion 130 and an inactive piezoelectric portion 131. The active piezoelectric portion 130 is a portion where electric charges are generated when a load is applied to the piezoelectric sensor 10. The inactive piezoelectric portion 131 is a portion where no charge is generated even when a load is applied.

In the piezoelectric sensor 10 according to the fourth embodiment, the piezoelectric layer 13 includes the active piezoelectric portion 130 and the inactive piezoelectric portion 131, and the first electrode 11 and the second electrode 12 are provided only on the active piezoelectric portion 130. It differs from the piezoelectric sensor of the first embodiment in that it is laminated.

When configured in this way, the charges generated at the portion of the piezoelectric layer 13 where the first electrode 11 and the second electrode 12 are not laminated leak out and are detected by the first electrode 11 and the second electrode 12. Can be prevented (crosstalk phenomenon can be prevented). As a result, position detection accuracy and load detection accuracy can be improved. In the above description, the first electrode 11 and the second electrode 12 are directly laminated on the active piezoelectric portion 130. However, the active piezoelectric portion 130 and the upper electrode 2 or the active piezoelectric portion 130 and the lower electrode are illustrated. Between 3, an insulating material such as an adhesive or a film may be laminated.

5. Other Embodiments In the above, the example in which the position and amount of the applied load are detected by the piezoelectric sensor 10 has been described. However, as shown in FIG. 9, instead of laminating the substrate 15 on the piezoelectric sensor 10, the position and amount of the applied load may be detected by laminating the touch panel 50.

By laminating the touch panel 50 on the piezoelectric sensor 10, the position of the applied load can be detected using the touch panel 50 even when the applied load is so small that it cannot be detected by the piezoelectric sensor 10 (in the case of feather touch). .

1: Pressure detection device 10: Piezoelectric sensor 11: First electrode 11a-11e: First unit electrode 12: Second electrode 12a-12e: Second unit electrode 13: Piezoelectric layer 14: Reference electrode 15: Substrate 16: Adhesive 20: detection unit 21: first detection unit 22: second detection unit 30: control unit 31: first control unit 32: second control unit 40: reference electrode 50: touch panel 130: active piezoelectric unit 131: inactive piezoelectric unit S: Switch S ′: Switch Q1, Q2, Q3: Charge q1, q2, q3: Charge amount

Claims

A piezoelectric layer;
A first electrode laminated on the first main surface of the piezoelectric layer;
A second electrode laminated with the first electrode on the first main surface of the piezoelectric layer;
A reference electrode laminated on a second main surface opposite to the first main surface of the piezoelectric layer, and a piezoelectric sensor comprising:
The first electrode extends from a first side of the piezoelectric layer to a second side opposite to the first side, and a plurality of the first electrodes become smaller as the size in the width direction approaches the second side. A first unit electrode of
The second electrode includes a plurality of second unit electrodes which extend in the same direction as the first unit electrode and become smaller as the size in the width direction approaches the first side,
The first unit electrode and the second unit electrode are piezoelectric sensors arranged to mesh with each other in plan view.
A piezoelectric layer;
A first electrode laminated on a first main surface of the piezoelectric layer;
A piezoelectric sensor comprising: a second electrode stacked on a second main surface opposite to the first main surface of the piezoelectric layer;
The piezoelectric layer includes a first piezoelectric layer in contact with the first electrode, a second piezoelectric layer in contact with the second electrode, and a reference electrode between the first piezoelectric layer and the second piezoelectric layer. One electrode extends from a first side of the piezoelectric layer to a second side opposite to the first side, and a plurality of first electrodes that become smaller as the size in the width direction approaches the second side. With one unit electrode,
The second electrode includes a plurality of second unit electrodes which extend in the same direction as the first unit electrode and become smaller as the size in the width direction approaches the first side,
The first unit electrode and the second unit electrode are piezoelectric sensors arranged to mesh with each other in plan view.
The first unit electrode comprises a triangle having a base on the first side of the piezoelectric layer and a vertex on the second side;
3. The piezoelectric sensor according to claim 1, wherein the second unit electrode is formed of a triangle having a base on the second side of the piezoelectric layer and a vertex on the first side.
Two or more adjacent first unit electrodes are coupled on the first side, and two or more adjacent second unit electrodes are coupled on the second side. Piezoelectric sensor.
The pitch length of the first unit electrode and the second unit electrode is the length of the short diameter of the contact surface formed between the input unit and the piezoelectric sensor when the input unit contacts the piezoelectric sensor. The piezoelectric sensor according to any one of claims 1 to 4, wherein the piezoelectric sensor is shorter.
The piezoelectric sensor according to claim 5, wherein the pitch length of the first unit electrode and the pitch length of the second unit electrode are 1 mm to 16 mm.
The piezoelectric sensor according to any one of claims 1 to 6, wherein the piezoelectric layer includes an active piezoelectric portion and an inactive piezoelectric portion, and the first unit electrode and the second unit electrode are disposed on the active piezoelectric portion.
The piezoelectric sensor according to any one of claims 1 to 7, wherein the first electrode includes indium tin oxide and polyethyldioxothiophene.
The piezoelectric sensor according to any one of claims 1 to 8, wherein the second electrode contains indium tin oxide or polyethyldioxothiophene.
10. The piezoelectric sensor according to claim 1, wherein the piezoelectric layer is made of an organic piezoelectric material.
The piezoelectric sensor according to claim 10, wherein the organic piezoelectric material contains polyvinylidene fluoride or polylactic acid.
10. The piezoelectric sensor according to claim 1, wherein the piezoelectric layer is made of an inorganic material.
An electronic device comprising the piezoelectric sensor of claim 1 to 12 and a touch panel.
The electronic device according to claim 13, wherein the touch panel is a capacitance type.