JP2015212708A - Piezoelectric sensor and pressure detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric sensor capable of performing position detection and load detection in a piezoelectric sensor.SOLUTION: A piezoelectric sensor 10 has a piezoelectric layer sandwiched between an upper electrode 12 and a bottom electrode 13. The upper electrode 12 includes a plurality of first pattern electrodes 14 extending in one direction. The bottom electrode 13 includes a plurality of second pattern electrodes 15 extending in the same direction as the first pattern electrodes 14. The piezoelectric sensor is formed so that sizes of the first pattern electrodes 14 and the second pattern electrodes 15 in width directions increase as they approach peripheral parts of the piezoelectric layer.

Description

  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.

  In order to detect a given load, a piezoelectric sensor using a piezoelectric layer is known. 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 the applied load, but cannot detect the position where the load is applied in the transparent piezoelectric sensor.

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

  In the piezoelectric sensor of the present invention, the piezoelectric layer is sandwiched between the upper electrode and the lower electrode. At least one of the upper electrode and the lower electrode includes a plurality of pattern electrodes.

  According to the above configuration, when a load is applied to the piezoelectric sensor and a charge is generated from the piezoelectric layer, the load is applied by specifying which electrode among the plurality of pattern electrodes has detected the charge. The position can be specified.

  A reference electrode may be provided between the upper electrode and the lower electrode. In such a case, a first piezoelectric layer may be provided between the upper electrode and the reference electrode, and a second piezoelectric layer may be provided between the lower electrode and the reference electrode.

  Then, the electric charges generated in the first piezoelectric layer and the second piezoelectric layer can be detected independently by the upper electrode and the lower electrode.

  The first pattern electrode may include a first connection part that electrically connects the first electrode part and the first electrode part. The second pattern electrode may also include a second electrode part and a second connection part. Further, the first electrode part may be provided on the piezoelectric layer so as to overlap the second electrode part.

  If it does so, it will become possible to detect the electric charge which generate | occur | produced from the piezoelectric layer by the 1st electrode part and the 2nd electrode part, and the detection of the position and load amount to which the load was applied will be attained.

  The 1st electrode part may be arranged so that it may overlap with a plurality of 2nd electrode parts via a piezoelectric layer.

  If it does so, the number of the location where a 1st electrode part and a 2nd electrode part overlap will increase more than the above-mentioned case. As a result, the position detection accuracy in the piezoelectric sensor is improved.

  The first pattern electrode may have a strip shape.

  The second pattern electrode may have a strip shape.

  The size of the first pattern electrode in the width direction may increase as it approaches the periphery of the piezoelectric layer.

  In this case, the load detection sensitivity is improved for the peripheral portion of the piezoelectric layer having a small amount of deflection when a load is applied and the load detection sensitivity is poor.

  The size of the second pattern electrode in the width direction may increase as it approaches the periphery of the piezoelectric layer.

  In this case, the load detection sensitivity is improved for the peripheral portion of the piezoelectric layer having a small amount of deflection when a load is applied and the load detection sensitivity is poor.

  The pitch interval of the first pattern electrodes may be constant.

  As a result, the position detection accuracy with respect to a given load is improved while maintaining the sensitivity of the peripheral edge portion constant.

  The pitch interval of the second pattern electrodes may be constant.

  As a result, the position detection accuracy with respect to a given load is improved while maintaining the sensitivity of the peripheral edge portion constant.

  The first pattern electrode has a concavo-convex shape composed of a convex portion and a concave portion, and the pitch interval of the first pattern electrodes is shorter than the length of the short diameter of the contact surface formed when the input means contacts the piezoelectric sensor. It may be designed. Furthermore, between the adjacent electrodes of the first pattern electrode, the convex portion and the concave portion may be engaged with each other.

  If it does so, when a piezoelectric sensor and a target object will contact, the number in which a 1st pattern electrode will contact a target object will increase. As a result, it is possible to detect the load position and the load amount with higher accuracy than in the above case.

  The second pattern electrode has a concavo-convex shape composed of a convex portion and a concave portion, and the pitch interval of the second pattern electrode is shorter than the length of the minor axis of the contact surface formed when the input means contacts the piezoelectric sensor. It may be designed. Furthermore, between the adjacent electrodes of the second pattern electrode, the convex portion and the concave portion may be configured to mesh with each other.

  If it does so, when a piezoelectric sensor and a target object will contact, the number which a target object and a 2nd pattern electrode will contact increases. As a result, it is possible to detect the load position and the load amount with higher accuracy than in the above case.

  The piezoelectric layer has an active piezoelectric portion and an inactive piezoelectric portion, and a first pattern 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 piezoelectric layer has an active piezoelectric part and an inactive piezoelectric part, and a second pattern electrode may be laminated on the active piezoelectric part.

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

    The upper electrode may contain indium tin oxide or polyethyldioxothiophene.

Then, since the transparency of the upper electrode is increased, the 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, a 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 is improved, the load detection sensitivity is improved.

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

  As a result, even when a load is hardly applied to the piezoelectric sensor, the position of the load can be detected.

  The touch panel may be a capacitive touch panel.

  If it does so, the transparency of the whole pressure detection apparatus will improve.

It is a conceptual diagram of a pressure detection apparatus. FIG. 2 is a cross-sectional view taken along the line A-A ′ of FIG. 1. It is a top view of a piezoelectric sensor. FIG. 4 is a B-B ′ sectional view of FIG. 3. It is a top view of a piezoelectric sensor. FIG. 6 is a C-C ′ sectional view of FIG. 5. It is a top view of a piezoelectric sensor. It is a top view of a piezoelectric sensor. It is a top view of a piezoelectric sensor. It is a top view of a piezoelectric sensor. It is a top view of a piezoelectric sensor. It is D-D 'sectional drawing of FIG. It is a top view of a piezoelectric sensor. It is E-E 'sectional drawing of FIG. 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.

  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.

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 is a device that detects charges generated by the piezoelectric sensor 10. The control unit 30 is a device that controls the switch S installed in the piezoelectric sensor 10. Below, the structure of the pressure detection apparatus 1 is demonstrated in detail.

(2) Piezoelectric Sensor As shown in FIG. 2, the piezoelectric sensor 10 has a configuration in which a piezoelectric layer 11 is sandwiched between an upper electrode 12 and a lower electrode 13. The upper electrode 12 is laminated on the upper surface of the piezoelectric layer 11, and the lower electrode 13 is laminated on the lower surface of the piezoelectric layer 11.

  As shown in FIG. 1 again, the upper electrode 12 includes a strip-shaped first pattern electrode 14. A plurality of first pattern electrodes 14 are arranged in the Y-axis direction. The lower electrode 13 is planar.

  When a load is applied to such a piezoelectric sensor 10, a charge corresponding to the applied load is generated in the piezoelectric layer 11. The generated charges are detected by the detection unit 20 via the first pattern electrode 14 and the lower electrode 13 existing in the vicinity of the load. At this time, the amount of load applied to the piezoelectric sensor 10 can be specified by measuring the amount of charge detected by the detection unit 20. As for the load position, the control unit 30 determines which of the first pattern electrodes 14 among the plurality of first pattern electrodes 14 the charges detected by the detection unit 20 are detected by the detection unit 20. It can be specified by detecting with.

(3) Piezoelectric layer Examples of the material constituting the piezoelectric layer 11 include inorganic piezoelectric materials and organic piezoelectric materials.

  Examples of the inorganic piezoelectric material 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 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.

  Moreover, when applying the pressure detection apparatus 1 to the display apparatus provided with the touch panel, it is preferable to comprise a piezoelectric part with a transparent material, or to thinly so that light can fully permeate | transmit.

(4) Electrode The upper electrode 12 and the lower electrode 13 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 (TZO), and polyethylenedioxythiophene. 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.

  Alternatively, 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.

(5) Detection Unit As shown in FIG. 1, the detection unit 20 has two inputs. One input is the top electrode 1
2 is connected. The other input is connected to the lower electrode 13.

  With the above configuration, the detection unit 20 can detect charges generated between the upper electrode 12 and the lower electrode 13 (that is, between both main surfaces of the piezoelectric layer 11) when the piezoelectric layer 11 is pressed. The detection unit 20 can use a detection device that combines an AD converter and an amplifier.

(6) Control Unit The control unit 30 is connected to the switch S that connects the upper electrode 12 and the detection unit 20 and the switch S that connects the lower electrode 13 and the detection unit 20. The control unit 30 has a function of outputting an ON / OFF switching signal for the switch S.

  The control unit 30 can be included in the drive system of the pressure detection device 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.

  Moreover, you may implement | achieve the said function of a control part by making a CPU, custom IC, etc. execute the program memorize | stored in memory | storage parts, such as the said microcomputer and custom IC.

  As described above, when the pressure detection device 1 is configured, the electric charge generated between the upper electrode 12 and the lower electrode 13 can be detected using the control unit 30. Then, it is possible to calculate the position and amount where the load is applied from the detected electric charge. Similarly, when there are a plurality of places where the load is applied, the position of each place and the amount of the load can be detected. That is, the pressure detection device 1 has a configuration capable of multi-force detection.

2. Second Embodiment In the first embodiment, the lower electrode 13 has a planar shape and does not have a pattern shape, but the lower electrode 13 may have a second pattern electrode 15.

  FIG. 3 is a plan view of the piezoelectric sensor according to the second embodiment. 4 is a cross-sectional view taken along the line B-B 'of FIG.

  As shown in FIG. 3, in addition to the above, the lower electrode 13 includes a strip-shaped second pattern electrode 15. A plurality of first pattern electrodes 14 and second pattern electrodes 15 are arranged in the Y-axis direction. The first pattern electrode 14 is stacked on the second pattern electrode 15 via the piezoelectric layer 11. As shown in FIGS. 3 and 4, the first pattern electrode 14 is laminated on the piezoelectric layer 11 so as to follow the shape of the second pattern electrode 15.

  When a load is applied to such a piezoelectric sensor 10, a charge corresponding to the applied load is generated in the piezoelectric layer 11. The generated charges are detected by the detection unit 20 via the first pattern electrode 14 and the second pattern electrode 15 existing in the vicinity of the load. At this time, the amount of load applied to the piezoelectric sensor 10 can be specified by measuring the amount of charge detected by the detection unit 20. As for the load position, the charge detected by the detection unit 20 passes through the first pattern electrode 14 and the second pattern electrode 15 among the plurality of first pattern electrodes 14 and second pattern electrodes 15. It can be specified by detecting by the control unit 30 whether it has been detected by the detection unit 20. Thereby, the position of the place where the load was loaded and the load amount of the loaded load can be detected.

  If comprised as mentioned above, since the lower electrode 13 is also patterned in addition to the upper electrode 12, position detection and load detection with higher accuracy than the above can be performed.

  In the above example, the first pattern electrode 14 and the second pattern electrode 15 are arranged in the Y-axis direction of the piezoelectric layer 11. However, the first pattern electrode 14 and the second pattern electrode 15 are arranged in the X-axis direction. May be.

3. Third Embodiment The method of laminating the first pattern electrode 14 and the second pattern electrode 15 is not limited to the case where the first pattern electrode 14 is laminated on the piezoelectric layer 11 so as to follow the shape of the second electrode portion 18. Hereinafter, other arrangement methods will be described.

  FIG. 5 is a plan view of the piezoelectric sensor according to the third embodiment. 6 is a cross-sectional view taken along the line C-C ′ of FIG. 5.

  As shown in FIG. 5, the first pattern electrode 14 is stacked on the piezoelectric layer 11 across the plurality of second pattern electrodes 15. By configuring as described above, the number of first pattern electrodes 14 stacked on the second pattern electrode 15 via the piezoelectric layer 11 is increased as shown in FIG. 6 (in the case of the second embodiment). 4, the number of overlapping portions of the first pattern electrode 14 and the second pattern electrode 15 is 4. On the other hand, in the case of the second embodiment, as shown in FIG. And the number of overlapping portions of the second pattern electrode 15 is eight). As a result, the number of detection points for detecting the input means increases, so that the position detection accuracy and load detection accuracy when the input means contacts the piezoelectric sensor 10 are improved.

4). Fourth Embodiment In the first and second embodiments, the length in the width direction of the first pattern electrode 14 and the second pattern electrode 15 is constant, but as the length approaches the peripheral edge of the piezoelectric layer 11, You may be comprised so that it may become long.

  7, 8, and 9 are plan views of the piezoelectric sensor according to the third embodiment.

  As shown in FIG. 7, the upper electrode 12 includes first pattern electrodes 14 arranged in a plurality in the Y-axis direction. Fixing members W for fixing the piezoelectric sensor 10 are provided at both ends of the piezoelectric sensor 10 in the Y-axis direction. The fixing member W is composed of an adhesive material or a fixing frame. In this case, the upper electrode 12 is configured such that the first pattern electrode 14 having a wider electrode width is disposed closer to the both end portions. The same applies to the second pattern electrode 15 of the lower electrode 13 (dotted line portion in FIG. 7).

  As shown in FIG. 8, fixing members W for fixing the piezoelectric sensor 10 may be provided at both ends in the X-axis direction of the piezoelectric sensor 10. In such a case, the upper electrode 12 includes a first electrode pattern 14 having a neck shape in which the width of the electrode becomes wider as it approaches the both end portions. The same applies to the second pattern electrode 15 of the lower electrode 13 (dotted line portion in FIG. 8).

  As shown in FIG. 9, a fixing member W for fixing the piezoelectric sensor 10 may be provided on the periphery of the piezoelectric sensor 10. In such a case, the upper electrode 12 may have a structure combining the above. That is, the upper electrode 12 includes a first electrode pattern 14 having a neck shape that increases in width as it approaches both ends in the X-axis direction. The first electrode pattern electrode 14 approaches the both ends in the Y-axis direction. The electrode may have a wide width. The same applies to the second pattern electrode 15 (dotted line portion in FIG. 9).

  As described above, when the piezoelectric sensor 10 is fixed by the fixing member W or the like, when a load is applied to the piezoelectric sensor 10, the portion where the fixing member W is provided or a portion in the vicinity thereof is not bent. It becomes difficult to transmit power. For this reason, it is difficult to detect the load at the above-described places.

  In the fourth embodiment, when the fixing members W are provided at both ends of the piezoelectric sensor 10 in the Y-axis direction, the upper electrode 1 has a first electrode pattern 14 having a larger electrode width as it approaches both ends in the Y-axis direction. When the fixing members W are provided at both ends of the piezoelectric sensor 10 in the X-axis direction, the upper electrode 12 has a wedge-shaped first shape in which the electrode width increases as it approaches both ends in the X-axis direction. By being configured to have one electrode pattern 14, the physical detection sensitivity of the electrode is improved, and the detection of the vicinity of the fixed member W where it is difficult to detect the load is made possible.

  In the fourth embodiment, the first pattern electrodes 14 may be arranged on the piezoelectric layer 11 so that the pitch interval L between the first pattern electrodes 14 is constant. The second pattern electrodes 15 may also be arranged on the piezoelectric layer 11 so that the pitch interval l between the second pattern electrodes 15 is constant. If comprised in this way, since the 1st pattern electrode 14 and the 2nd pattern electrode 15 are arrange | positioned on the piezoelectric layer 11 at equal intervals, in addition to the above, an exact position detection is attained. The pitch interval is a distance from the center portion of the electrode to the center portion of the adjacent electrode.

5. Fifth Embodiment The first pattern electrode 14 and the second pattern electrode 15 are not limited to other ones as long as they extend in the same direction. Therefore, the shape of the first pattern electrode 14 and the second pattern electrode 15 is not particularly limited to a belt shape. Hereinafter, the shape of the electrode will be described.

  FIG. 10 is a plan view of the piezoelectric sensor according to the fourth embodiment.

  As shown in FIG. 10, the first pattern electrode 14 has an uneven shape. This concavo-convex shape is a repetitive shape corresponding to a convex portion and a concave portion. The first pattern electrode 14 is arranged on the piezoelectric layer 11 so that the convex portion and the concave portion are engaged with each other in the first pattern electrode 14.

  The pitch length L of the first pattern electrode is designed to be shorter than the length of the short diameter of the contact surface when the input means (for example, a finger or a stylus pen) and the pressure sensor 10 are in contact. . When the input means is a finger, the pitch length L of the convex portion is 1 mm to 16 mm, and when the input means is a stylus pen, the pitch length is 0.5 mm to 4 mm.

  Then, when the input unit and the pressure sensor 10 are in contact with each other, the input unit is in contact with many first pattern electrodes 14 as compared with the case where the shape of the first pattern electrode 14 is a band shape. As a result, more accurate position detection and load detection are possible.

  Similarly, the second pattern electrode 15 may have an uneven shape. In such a case, it is preferable that the pitch length l of the convex portion of the second pattern electrode 15 is designed to be shorter than the length of the short diameter of the contact surface when the input means and the pressure sensor 10 are in contact.

  If comprised as mentioned above, when an input means and the pressure sensor 10 will contact, an input means will contact the 1st pattern electrode 14 and the 2nd pattern electrode 15 of more. Therefore, more accurate position detection and load detection are possible.

6). Sixth Embodiment Other pattern shapes of the first pattern electrode 14 and the second pattern electrode 15 will be described below.

  FIG. 11 is a plan view of the piezoelectric sensor according to the sixth embodiment. 12 is a cross-sectional view taken along the line D-D ′ of FIG. 11.

As shown in FIG. 11, the first pattern electrode 14 includes a plurality of first electrode portions 16 arranged in the X-axis direction and a first connection portion 17 that electrically connects the first electrode portions 16 to each other. .
The second pattern electrode 15 includes a plurality of second electrode portions 18 (FIG. 11: diamond dotted line portions) arranged in the X-axis direction and a second connection portion 19 (FIG. 11) that electrically connects the second electrode portions 18 to each other. : Dotted line part). In addition, although the shape of the 1st electrode part 16 and the 1st electrode part 18 was shown by the rhombus shape in FIG. 9, polygonal shapes, such as a triangle and a quadrangle | tetragon, a circle | round | yen, and an ellipse shape may be sufficient.

  As shown in FIGS. 11 and 12, the first electrode portion 16 is stacked on the piezoelectric layer 11 so as to follow the shape of the second electrode portion 18. Then, when an input means (for example, a finger or a stylus pen) comes into contact with the first electrode unit 16, the charge generated in the piezoelectric layer 11 passes through the first electrode unit 16 and the second electrode unit 18 and is detected by the detection unit 20. Detected. At this time, the amount of load applied to the piezoelectric sensor 10 can be specified by measuring the amount of charge detected by the detection unit 20. As for the load position, the charge detected by the detection unit 20 passes through the first pattern electrode 14 and the second pattern electrode 15 among the plurality of first pattern electrodes 14 and second pattern electrodes 15. It can be specified by detecting by the control unit 30 whether it has been detected by the detection unit 20.

7). Seventh Embodiment The method of laminating the first pattern electrode 14 and the second pattern electrode 15 is not limited to the case where the first electrode portion 16 is laminated on the piezoelectric layer 11 so as to follow the shape of the second electrode portion 18. Hereinafter, other arrangement methods will be described. Since the basic configuration is the same as that of the sixth embodiment, only the differences will be described.

  FIG. 13 is a plan view of the piezoelectric sensor according to the seventh embodiment. 14 is a cross-sectional view taken along the line E-E 'of FIG.

  As shown in FIG. 13, a plurality of first pattern electrodes 14 are arranged in the Y-axis direction. Further, the first pattern electrode 14 is disposed on the piezoelectric layer 11 so as to mesh with each other. The second pattern electrode is also disposed on the piezoelectric layer 11 so as to be engaged with each other between the adjacent second pattern electrodes 15.

  In addition, in the above, the 1st electrode part 16 is arrange | positioned so that it may straddle on the four 2nd electrode parts 18 arrange | positioned at four directions.

  When the piezoelectric sensor 10 is configured as described above, the number of the first electrode portions 16 stacked on the second electrode portion 18 is increased (in the case of the sixth embodiment, as shown in FIG. The number of overlapping portions of the electrode portion 16 and the second electrode portion 18 is three, whereas in the case of the seventh embodiment, it is six as shown in FIG. As a result, since the number of detection points increases, the position detection accuracy and load detection accuracy when the input means contacts the piezoelectric sensor 10 are improved.

  Furthermore, as described above, the first pattern electrodes 14 are arranged so as to mesh with each other, so that the electrodes are spread on the piezoelectric layer 10 without any gaps. This is the same when the second pattern electrodes 15 are arranged so as to mesh with each other. As a result, the piezoelectric sensor 10 is difficult to see the pattern shapes of the first pattern electrode 14 and the second pattern electrode 15 pattern electrode.

8). Eighth Embodiment In addition to the upper electrode 12 and the lower electrode 13, the piezoelectric layer 11 may be patterned so as to have an active portion and an inactive portion.

  FIG. 15 is a cross-sectional view of the piezoelectric sensor according to the eighth embodiment.

  As shown in FIG. 15, the piezoelectric layer 11 includes an active piezoelectric portion 110 and an inactive piezoelectric portion 111. The active piezoelectric portion 110 is a portion where electric charges are generated when a load is applied to the piezoelectric sensor 10. On the other hand, the inactive piezoelectric portion 111 is a portion where no charge is generated even when a load is applied.

  In the example of FIG. 15, the first pattern electrode 14 and the second pattern electrode 15 are disposed above and below the active piezoelectric portion 110. With such a configuration, it is possible to prevent electric charges generated near the first pattern electrode 14 from leaking and mixing into other first pattern electrodes 14 (a crosstalk phenomenon can be prevented). As a result, position detection accuracy and load detection accuracy are improved. In the above description, an example in which the first pattern electrode 14 and the second pattern electrode 15 are directly laminated on the active piezoelectric portion 110 has been described. However, the active piezoelectric portion 110 or the active piezoelectric portion is interposed between the active piezoelectric portion 110 and the first pattern electrode 14. Between 110 and the 2nd pattern electrode 15, insulating materials, such as an adhesive agent and a film, may be laminated | stacked.

9. Ninth Embodiment In the above description, the configuration in which the piezoelectric layer is sandwiched between the upper electrode and the lower electrode has been described. However, a reference electrode may be provided between the upper electrode and the lower electrode.

  FIG. 16 is a cross-sectional view of the piezoelectric sensor according to the ninth embodiment.

As shown in FIG. 16, the piezoelectric sensor 10 of the ninth embodiment includes a reference electrode 40 between the upper electrode 12 and the lower electrode 13. A first piezoelectric layer 11 a is provided between the upper electrode 12 and the reference electrode 40. Between the lower electrode 13 and the reference electrode 40, the second piezoelectric layer 11b is provided. The material of the first piezoelectric layer 11 a and the second piezoelectric layer 11 b is the same as that of the piezoelectric layer 11. The material of the reference electrode 40 is also the same as that of the upper electrode 12 and the lower electrode 13.
As described above, when the reference electrode 40 is provided between the upper electrode 12 and the lower electrode 13, the charges generated in the first piezoelectric layer 11 a and the second piezoelectric layer 11 b are independently generated by the upper electrode 12 and the lower electrode 13. Can be detected. As a result, the design of the detection circuit is simplified.

10. 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. 17, the position and amount of the applied load may be detected by laminating the touch panel 50 on the piezoelectric sensor 10.
By laminating the touch panel 50 on the piezoelectric sensor 10, even if the applied load is so small that it cannot be detected by the piezoelectric sensor 10 (in the case of feather touch), the load is obtained by laminating the touch panel 50 on the piezoelectric sensor 10. Can be detected. Of the touch panels, it is particularly preferable to use a capacitive touch panel.

1: Pressure detection device 10: Piezoelectric sensor 11: Piezoelectric layer 11a: First piezoelectric layer 11b: Second piezoelectric layer 12: Upper electrode 13: Lower electrode 14: First pattern electrode 15: Second pattern electrode 16: First electrode Unit 17: First connection unit 18: First electrode unit 19: Second connection unit 20: Detection unit 30: Control unit 40: Reference electrode 50: Electrostatic touch panel 110: Active piezoelectric unit 111: Inactive piezoelectric unit S: Switch L: Pitch interval between first pattern electrodes l: Pitch interval between first pattern electrodes

Claims (8)

A piezoelectric sensor in which a piezoelectric layer is sandwiched between an upper electrode and a lower electrode,
The upper electrode is
A plurality of first pattern electrodes extending in one direction;
The lower electrode is
A plurality of second pattern electrodes extending in the same direction as the first pattern electrodes;
A piezoelectric sensor in which the size of the first pattern electrode in the width direction increases as it approaches the peripheral edge of the piezoelectric layer. A piezoelectric sensor in which a piezoelectric layer is sandwiched between an upper electrode and a lower electrode,
The upper electrode is
A plurality of first pattern electrodes extending in one direction;
The lower electrode is
A plurality of second pattern electrodes extending in the same direction as the first pattern electrodes;
A piezoelectric sensor in which the size of the second pattern electrode in the width direction increases as it approaches the peripheral edge of the piezoelectric layer.   2. The piezoelectric sensor according to claim 1, wherein the size of the second pattern electrode in the width direction increases as it approaches the peripheral edge of the piezoelectric layer. The piezoelectric layer is
A first piezoelectric layer in contact with the upper electrode;
A second piezoelectric layer in contact with the lower electrode,
The piezoelectric sensor according to claim 1, further comprising a reference electrode between the first piezoelectric layer and the second piezoelectric layer.   The piezoelectric sensor according to claim 1, wherein the piezoelectric layer includes an active piezoelectric portion and an inactive piezoelectric portion, and the first pattern electrode is stacked on the active piezoelectric portion.   The piezoelectric sensor according to claim 1, wherein the piezoelectric layer includes an active piezoelectric portion and an inactive piezoelectric portion, and the second pattern electrode is stacked on the active piezoelectric portion.   A pressure detection apparatus comprising the piezoelectric sensor according to claim 1 and a touch panel.   The pressure detection device according to claim 7, wherein the touch panel is a capacitive touch panel.

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