Pressure sensor and position detection device

Abstract

To precisely locate a position to which external force is actually applied from among a plurality of pressure application positions.SOLUTION: A pressure sensor includes: a board; a lower electrode; a first piezoelectric layer in which a piezoelectric body is formed on the lower electrode; an intermediate electrode formed on the first piezoelectric layer; a second piezoelectric layer in which a piezoelectric body having a thickness differing from that of the first piezoelectric layer is formed on the intermediate electrode; an upper electrode formed on the second piezoelectric layer; a pressure application part formed on the upper electrode; a signal reception part for receiving a first detection signal outputted from the lower electrode and the intermediate electrode and a second detection signal outputted from the intermediate electrode and the upper electrode; and an external force identification part for identifying magnitude of external force applied to the pressure application part on the basis of the first detection signal and the second detection signal. A piezoelectric body having a fixed thickness is formed in at least one of the first piezoelectric layer and the second piezoelectric layer.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a pressure sensor and a position detection device. [Background technology]

[0002] Conventionally, a sensor element using the piezoelectric effect has been known, in which a piezoelectric body is sandwiched between two electrodes and an external force is applied so as to distort the piezoelectric body, thereby generating a voltage between the two electrodes. A position detection device is also known that detects the position where an external force is applied by arranging a plurality of such sensor elements (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-163531 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such a position detection device, a sensor element is disposed for each position to be detected. In this case, the number of sensor elements increases as the number of positions to be detected increases, which causes a problem that the position detection device becomes complicated.

[0005] Therefore, the present invention has been made in consideration of these points, and aims to make it possible to accurately identify the position to which an external force is actually applied from among multiple pressure application positions, without arranging multiple sensor elements. [Means for solving the problem]

[0006] In a first aspect of the present invention, there is provided a pressure sensor comprising: a substrate; a lower electrode formed on the substrate; a first piezoelectric layer in which a piezoelectric body is formed on the lower electrode; an intermediate electrode formed on the first piezoelectric layer; a second piezoelectric layer in which a piezoelectric body having a different thickness than the first piezoelectric layer is formed on the intermediate electrode; an upper electrode formed on the second piezoelectric layer; a pressure application section formed on the upper electrode to which pressure is applied from the outside; a signal receiving section receiving a first detection signal output from the lower electrode and the intermediate electrode and a second detection signal output from the intermediate electrode and the upper electrode; and an external force identification section identifying a magnitude of an external force applied to the pressure application section based on the first detection signal and the second detection signal received by the signal receiving section, wherein at least one of the first piezoelectric layer and the second piezoelectric layer is formed with a piezoelectric body having a constant thickness.

[0007] The external force identification unit may identify a normalized magnitude of the external force applied to the pressure application unit by normalizing the second detection signal using the first detection signal as a reference signal, or by normalizing the first detection signal using the second detection signal as a reference signal.

[0008] The pressure application sections are formed in plurality on the upper electrode, one of the first piezoelectric layer and the second piezoelectric layer is formed with a constant piezoelectric thickness as a reference piezoelectric layer for generating the reference signal, and the other of the first piezoelectric layer and the second piezoelectric layer, which is different from the reference piezoelectric layer, is formed as a detection piezoelectric layer, and the detection piezoelectric layer has a piezoelectric formed such that the volume of the piezoelectric per unit area varies depending on the position of the pressure application section in a plane parallel to the substrate, and the signal receiving section may receive the first detection signal and the second detection signal generated based on the pressure application section to which an external force is applied among the plurality of pressure application sections.

[0009] The thickness of the detection piezoelectric layer may vary depending on the position of the pressure application portion. The detection piezoelectric layer may have an area within a region corresponding to the pressure application portion in a plane parallel to the substrate that varies depending on the position of the pressure application portion.

[0010] The detection piezoelectric layer may have a plurality of piezoelectric regions corresponding to a plurality of the pressure application sections, and a gap region in which no piezoelectric material is formed may be provided between each of the plurality of piezoelectric regions and the other piezoelectric regions.

[0011] The detection piezoelectric layer may have a plurality of voids in which no piezoelectric material is formed, and the volume of the void in a first piezoelectric region of the detection piezoelectric layer corresponding to a first pressure application section may be different from the volume of the void in a second piezoelectric region of the detection piezoelectric layer corresponding to a second pressure application section different from the first pressure application section.

[0012] In a second aspect of the present invention, there is provided a position detection device comprising the pressure sensor of the first aspect, a memory unit that stores pressure application unit data in which the positions of a plurality of the pressure application units in a plane parallel to the substrate are associated with reference values ​​of the magnitude of the external force detected when pressure is applied to each of the pressure application units, and a position identification unit that identifies the position of the pressure application unit to which an external force is applied based on the magnitude of the external force identified by the external force identification unit and the pressure application unit data. Effect of the Invention

[0013] According to the present invention, it is possible to accurately identify the position to which an external force is actually applied from among a plurality of pressure application positions without disposing a plurality of sensor elements. [Brief description of the drawings]

[0014] [Figure 1] 2 shows an example of the configuration of a position detection device 10 for comparison. [Diagram 2] 1 shows a first configuration example of a position detection device 100 for comparison. [Diagram 3]2 shows a second configuration example of the position detection device 100 for comparison. [Figure 4] 1 shows a first configuration example of a position detection device 100 according to the present embodiment. [Diagram 5] 2 shows a second configuration example of the position detection device 100 according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Configuration example of position detection device 10 for comparison> 1 shows a configuration example of a position detection device 10 for comparison. In this embodiment, three orthogonal axes are shown as an X-axis, a Y-axis, and a Z-axis. The position detection device 10 includes a pressure sensor 20 and a signal processing unit 30. The pressure sensor 20 includes a pressure application unit 40, a substrate 50, a sensor element 60, a base layer 70, a protective film 80, and wiring 90.

[0016] A plurality of pressure application units 40 are provided in the position detection device 10, and pressure is applied from the outside. FIG. 1 shows an example in which three pressure application units 40, a first pressure application unit 40A, a second pressure application unit 40B, and a third pressure application unit 40C, are provided in the position detection device 10. Pressure is applied to the pressure application units 40, for example, by an operation by a user or the like. As an example, the pressure application unit 40 is pressed by the fingertip of the user. The pressure application unit 40 is formed in the shape of, for example, a push button or a key button. Alternatively, the plurality of pressure application units 40 may be a plurality of regions that are divided by printing or the like on the upper surface of an elastic plate-like or film-like member. The pressure application unit 40 is attached to, for example, a housing not shown.

[0017] The substrate 50 has a surface approximately parallel to the XY plane, and components such as the sensor element 60 are formed on the surface. The substrate 50 is preferably a component for maintaining the strength of the position detection device 10. The substrate 50 is formed of, for example, a bendable material. In this case, the substrate 50 is a PEN (polyethylene naphthalate) film, a PET (polyethylene terephthalate) film, a flexible substrate, or the like.

[0018] A plurality of sensor elements 60 are formed on the substrate 50. The sensor elements 60 may be formed on the upper surface of a base layer 70 formed on the upper surface of the substrate 50. The base layer 70 is, for example, a cross-linked PVP (polyvinylpyrrolidone) film. The sensor elements 60 detect pressure applied from the outside. One sensor element 60 is provided corresponding to one pressure application section 40, and is arranged so as to detect that one pressure application section 40 is pressed. FIG. 1 shows an example in which three sensor elements 60 are formed on the substrate 50 corresponding to three pressure application sections 40. The sensor element 60 has a lower electrode 62, an upper electrode 64, and a piezoelectric layer 66.

[0019] The lower electrode 62 and the upper electrode 64 are formed of a conductive material. It is preferable that the lower electrode 62 and the upper electrode 64 include a metal material. The lower electrode 62 and the upper electrode 64 are formed with a piezoelectric layer 66 sandwiched therebetween.

[0020] The piezoelectric layer 66 is a portion where a piezoelectric body is formed on the upper surface of the lower electrode 62. The piezoelectric body is a ferroelectric material having a piezoelectric effect. The piezoelectric body is, for example, a polymer such as PVDF (polyvinylidene fluoride) or a piezoelectric ceramic such as PZT (lead zirconate titanate).

[0021] The protective film 80 is formed so as to cover the multiple sensor elements 60. The protective film 80 is made of a resin or the like. The protective film 80 is made of a polymer such as parylene. The pressure application unit 40 is provided on the protective film 80. The pressure application unit 40 may be provided so as to be in contact with the protective film 80 when not pressed, or alternatively, may be provided so as to have a gap between the pressure application unit 40 and the protective film 80.

[0022] The wiring 90 electrically connects the lower electrode 62 and the upper electrode 64 of the sensor element 60 to the signal processing unit 30. The wiring 90 is provided for each sensor element 60. The signal processing unit 30 detects a voltage generated from the sensor element 60 and identifies the sensor element 60 to which pressure has been applied among the multiple sensor elements 60. Furthermore, the signal processing unit 30 can identify the pressure application unit 40 corresponding to the identified sensor element 60 as the pressure application unit 40 to which an external force has been applied.

[0023] As described above, in the pressure sensor 20, the sensor element 60 is disposed in correspondence with the position of the pressure application unit 40 so that when the pressure application unit 40 is pressed, pressure is applied to the piezoelectric layer 66. The sensor element 60 generates a voltage between the lower electrode 62 and the upper electrode 64 according to the pressure applied to the piezoelectric layer 66 due to the piezoelectric effect.

[0024] 1, when the user presses the pressure application unit 40 with his / her finger, the sensor element 60 generates a voltage larger than the steady state voltage. When the user removes his / her finger from the pressure application unit 40 after pressing the pressure application unit 40 with his / her finger, the sensor element 60 generates a voltage smaller than the steady state voltage. The signal processing unit 30 identifies the sensor element 60 to which pressure has been applied, for example, by detecting the maximum amplitude value of such a detection waveform.

[0025] The position detection device 10 described above can function as an input device that detects a user's operation input. In the position detection device 10, for example, the sensor element 60A generates a voltage in response to the user pressing the first pressure application unit 40A with a finger. Therefore, the signal processing unit 30 can detect that the first pressure application unit 40A at a position corresponding to the sensor element 60A has been pressed in response to a predetermined voltage value being generated from the wiring 90 connected to the sensor element 60A. The signal processing unit 30 outputs the detected information of the pressure application unit 40 to an external circuit, device, or the like.

[0026] Thus, the position detection device 10 is configured as an input device such as a touch panel, a numeric keypad, a keyboard, etc. Since the position detection device 10 uses the piezoelectric effect, it can reduce false detection even when water droplets or dust are present, compared to input devices that use capacitance.

[0027] In such a position detection device 10, there may be cases where it is desired to improve the position detection resolution or increase the number of pressure application units 40 to which input is possible. In this case, a sensor element 60 must be arranged at each position where the pressure of the pressure sensor 20 is to be detected. However, by increasing the number of sensor elements 60, the arrangement of the sensor elements 60, the arrangement of the wiring 90, the circuitry of the signal processing unit 30, etc. become complicated, which may make it difficult to manufacture, maintain, inspect, etc. the position detection device 10. Therefore, the comparative position detection device 100 is capable of detecting the position of the pressure application unit 40 to which pressure is actually applied from among multiple pressure application units 40 without arranging multiple sensor elements 60, etc.

[0028] <First Configuration Example of Position Detection Device 100 for Comparison> Fig. 2 shows a first configuration example of a comparative position detection device 100. In the comparative position detection device 100, parts that operate substantially the same as those in the comparative position detection device 10 shown in Fig. 1 are given the same reference numerals, and duplicated explanations will be omitted. The position detection device 100 includes a pressure sensor 110 and a signal processing unit 150. The pressure sensor 110 includes a pressure application unit 40, a substrate 50, a base layer 70, a protective film 80, wiring 90, a lower electrode 120, an upper electrode 130, and a piezoelectric layer 140.

[0029] The lower electrode 120 is formed on a substrate 50. Fig. 2 shows an example in which the lower electrode 120 is formed on the upper surface of the underlayer 70. The lower electrode 120 is preferably formed as a single unit. The upper electrode 130 is formed on a piezoelectric layer 140. The upper electrode 130 is preferably formed on the upper surface of the piezoelectric layer 140. The upper electrode 130 is preferably formed as a single unit. The lower electrode 120 and the upper electrode 130 are formed of a conductive material.

[0030] The piezoelectric layer 140 is a portion where a piezoelectric body is formed on the lower electrode 120. The piezoelectric layer 140 is desirably formed on the upper surface of the lower electrode 120. The piezoelectric body is a ferroelectric material that has a piezoelectric effect. The piezoelectric body is, for example, a polymer such as PVDF (polyvinylidene fluoride) or a piezoelectric ceramic such as PZT (lead zirconate titanate).

[0031] As described above, the comparative position detection device 100 has a lower electrode 120, an upper electrode 130, and a piezoelectric layer 140 formed thereon, instead of the multiple sensor elements 60 of the comparative position detection device 10. In other words, the position detection device 100 has a common lower electrode 120 and a common upper electrode 130 sandwiched between them by the piezoelectric layer 140. The pressure application section 40 is formed on the upper electrode 130 with the protective film 80 interposed therebetween.

[0032] In the piezoelectric layer 140, the piezoelectric material is formed such that the volume of the piezoelectric material per unit area in a plane (XY plane) approximately parallel to the substrate 50 varies depending on the position of the pressure application section 40. Fig. 2 shows an example in which the thickness of the piezoelectric layer 140 varies depending on the position of the pressure application section 40. The piezoelectric effect of the piezoelectric layer 140 generates different voltages depending on the volume of the piezoelectric material to which pressure is applied, even when the same pressure is applied to the piezoelectric material.

[0033] For example, when an external force is applied to the first pressure application section 40A, a part of the piezoelectric layer 140 to which pressure is applied in correspondence with the first pressure application section 40A directly below the first pressure application section 40A is defined as a first piezoelectric region 141. When an external force is applied to the second pressure application section 40B, a part of the piezoelectric layer 140 to which pressure is applied in correspondence with the second pressure application section 40B directly below the second pressure application section 40B is defined as a second piezoelectric region 142. Similarly, when an external force is applied to the third pressure application section 40C, a part of the piezoelectric layer 140 to which pressure is applied is defined as a third piezoelectric region 143.

[0034] 2, the thickness of the first piezoelectric region 141 in the direction perpendicular to the substrate 50 (Z-axis direction) is formed to be thinner than the thickness of the second piezoelectric region 142, and therefore the volume of the first piezoelectric region 141 is smaller than the volume of the second piezoelectric region 142. Similarly, the volume of the second piezoelectric region 142 is smaller than the volume of the third piezoelectric region 143.

[0035] The larger the volume of the piezoelectric body, the greater the amount of charge output from the piezoelectric body. Therefore, in the case of the pressure sensor 110 having the structure shown in FIG. 2, when an external force of a certain magnitude is applied to each of the first pressure application section 40A, the second pressure application section 40B, and the third pressure application section 40C, the voltages generated by the piezoelectric layer 140 are different from each other. For example, the magnitude of the voltage generated from the first piezoelectric region 141 when an external force of a certain magnitude is applied to the first pressure application section 40A is smaller than the magnitude of the voltage generated from the second piezoelectric region 142 when an external force of approximately the same magnitude as the external force is applied to the second pressure application section 40B. Therefore, by detecting the value of the voltage generated in the common lower electrode 120 and upper electrode 130, it is possible to determine which pressure application section 40 the external force has been applied to.

[0036] The wiring 90 transmits the voltages thus generated in the lower electrode 120 and the upper electrode 130 as detection signals to the signal processing unit 150. The signal processing unit 150 identifies the pressure application unit 40 to which the external force has been applied, based on the waveform (e.g., amplitude) of the detection signal output from the pressure sensor 110. The signal processing unit 150 has a signal receiving unit 160, an identifying unit 170, and a storage unit 180.

[0037] The signal receiving unit 160 receives the detection signals output from the upper electrode 130 and the lower electrode 120. The signal receiving unit 160 includes, for example, an amplifier circuit, an A / D conversion circuit, etc., and converts the received detection signals into digital signals. The signal receiving unit 160 supplies the converted digital signals to the identification unit 170.

[0038] The identifying unit 170 identifies the position of the pressure application unit 40 to which the external force is applied, based on the detection signal and the pressure application unit data received by the signal receiving unit 160. The pressure application unit data is data in which the positions of the multiple pressure application units 40 on a plane parallel to the substrate 50 are associated with reference values ​​of the detection signals when pressure is applied to each of the pressure application units 40.

[0039] For example, the average value of the maximum amplitude of the voltage generated from the first piezoelectric region 141 by pressing the first pressure application unit 40A with a finger is V1ave, and the allowable error value is ΔV. In this case, the reference value ST1 of the detection signal corresponding to the first pressure application unit 40A is a value (V1ave-ΔV) obtained by subtracting the allowable error value from the average value. Similarly, the reference value ST2 of the detection signal corresponding to the second pressure application unit 40B is a value (V2ave-ΔV) obtained by subtracting the allowable error value from the average value of the maximum amplitude of the voltage generated from the second piezoelectric region 142 by pressing the second pressure application unit 40B with a finger. Similarly, the reference value ST3 of the detection signal corresponding to the third pressure application unit 40C is V3ave-ΔV.

[0040] In this case, the identifying unit 170 identifies the pressure applying unit 40 to which the external force is applied as the first pressure applying unit 40A in response to, for example, the maximum amplitude value of the detection signal being smaller than the reference value ST2 and being equal to or greater than the reference value ST1. Similarly, the identifying unit 170 identifies the pressure applying unit 40 to which the external force is applied as the second pressure applying unit 40B in response to the maximum amplitude value of the detection signal being smaller than the reference value ST3 and being equal to or greater than the reference value ST2. The identifying unit 170 may also identify the pressure applying unit 40 to which the external force is applied as the third pressure applying unit 40C in response to the maximum amplitude value of the detection signal being equal to or greater than the reference value ST3.

[0041] Alternatively, two values ​​indicating a range of voltage values ​​may be set as the reference value of the detection signal for one pressure application unit 40. For example, the reference value of the detection signal corresponding to the first pressure application unit 40A is a value ST1m (V1ave-ΔV) obtained by subtracting the allowable error value from the average value, and a value ST1p (V1ave+ΔV) obtained by adding the allowable error value to the average value.

[0042] In this case, the identifying unit 170 identifies the pressure application unit 40 to which the external force has been applied as the first pressure application unit 40A, for example, in response to the maximum amplitude value of the detection signal being smaller than the reference value ST1p and being equal to or larger than the reference value ST1m. By using the reference value determined by a statistical method or the reference value determined from the design value or the like in this manner, the identifying unit 170 can more accurately identify the pressure application unit 40 to which the external force has been applied.

[0043] The identification unit 170, for example, supplies information on the identified position where the external force is applied to an external circuit, device, etc. Furthermore, the identification unit 170 may display the information on the identified position where the external force is applied on a display unit, etc. The identification unit 170 may store the information on the identified position where the external force is applied in the storage unit 180. Such an identification unit 170 is, for example, a CPU, etc.

[0044] The storage unit 180 stores pressure application unit data in which the positions of the multiple pressure application units 40 are associated with reference values ​​of detection signals. The storage unit 180 may store setting values, thresholds, parameters, and the like used by the identification unit 170 for operation. When the CPU or the like operates as at least a part of the identification unit 170, the storage unit 180 may store information of a program executed by the CPU or the like. The storage unit 180 may also store various information including a database referenced when the program is executed.

[0045] The storage unit 180 includes, for example, a ROM (Read Only Memory) that stores a BIOS (Basic Input Output System) and the like, and a RAM (Random Access Memory) that serves as a working area. Thereby, the CPU and the like function as the identification unit 170 by executing the programs stored in the storage unit 180.

[0046] As described above, in the pressure sensor 110 to be compared, the volume per unit area of ​​the piezoelectric material in the piezoelectric layer 140 differs depending on the position of the pressure application unit 40, and therefore the maximum amplitude value of the detection signal generated when an external force is applied differs depending on the position of the pressure application unit 40. Therefore, the position detection device 100 can identify the position of the pressure application unit 40 corresponding to the area of ​​the piezoelectric layer 140 where the detection signal is generated by comparing the maximum amplitude value of the detection signal of the pressure sensor 110 with a plurality of reference values.

[0047] The pressure sensor 110 having such a piezoelectric layer 140 can be simply configured using a common lower electrode 120 and upper electrode 130 sandwiching the piezoelectric layer 140, without providing a plurality of sensor elements 60. The position detection device 100 can reduce the number of wirings 90 by using the pressure sensor 110 having such a simple configuration. Furthermore, the position detection device 100 can easily identify the position of the pressure application unit 40 to which an external force has actually been applied, among the plurality of pressure application units 40, by simply converting the detection signals output from the common lower electrode 120 and upper electrode 130 into digital signals and performing digital processing.

[0048] In the above comparative pressure sensor 110, an example has been described in which the thickness of the piezoelectric layer 140 varies depending on the position of the pressure application section 40, but the present invention is not limited to this. In the pressure sensor 110, it is sufficient that the volume per unit area of ​​the piezoelectric of the piezoelectric layer 140 varies depending on the position of the pressure application section 40, and the piezoelectric layer 140 may be formed such that the area within a region corresponding to the pressure application section 40 in a plane parallel to the substrate 50 varies depending on the position of the pressure application section 40.

[0049] For example, in a plan view on a plane parallel to the substrate 50, the area of ​​the first piezoelectric region 141 corresponding to the first pressure application section 40A may be formed to be smaller than the area of ​​the second piezoelectric region 142 corresponding to the second pressure application section 40B. Similarly, in a plan view, the area of ​​the second piezoelectric region 142 corresponding to the second pressure application section 40B may be formed to be smaller than the area of ​​the third piezoelectric region 143 corresponding to the third pressure application section 40C.

[0050] This allows the volume per unit area of ​​the piezoelectric of the piezoelectric layer 140 to be varied depending on the position of the pressure application section 40. The thickness of the piezoelectric layer 140 in the vertical direction of the substrate 50 may be formed to be approximately constant. In this case, the upper electrode 130 and the lower electrode 120 are formed approximately parallel to each other, sandwiching the piezoelectric layer 140 of approximately constant thickness. Such upper electrode 130 and lower electrode 120 do not have any portions formed in a stepped shape, so they are easy to manufacture and are less likely to suffer from defects such as step discontinuities that adversely affect electrical characteristics.

[0051] The piezoelectric regions of the piezoelectric layer 140 may be separated by gaps or the like. The piezoelectric regions of the piezoelectric layer 140 may be formed to have different volumes due to voids or the like. A position detection device 100 having such a pressure sensor 110a will be described below.

[0052] <Second Configuration Example of Position Detection Device 100 for Comparison> 3 shows a second configuration example of a comparative position detection device 100. The piezoelectric layer 140 of the pressure sensor 110a of the comparative second configuration example has a plurality of piezoelectric regions corresponding to a plurality of pressure application units 40, and shows an example in which a gap region 144 where no piezoelectric is formed is provided between each of the plurality of piezoelectric regions and the other piezoelectric regions. In this way, by separating the plurality of piezoelectric regions, when pressure is applied to one piezoelectric region, it is possible to prevent pressure from also being applied to adjacent piezoelectric regions, and it is possible to reduce noise components in the detection signal.

[0053] Furthermore, a plurality of voids 146 in which no piezoelectric body is formed are further formed in the piezoelectric layer 140. The piezoelectric layer 140 is formed such that the volume of the voids 146 in the first piezoelectric region 141 of the piezoelectric layer 140 corresponding to the first pressure application section 40A is different from the volume of the voids 146 in the second piezoelectric region 142 of the piezoelectric layer 140 corresponding to the second pressure application section 40B different from the first pressure application section 40A.

[0054] This allows the piezoelectric layer 140 to be formed so that the volume per unit area of ​​the piezoelectric body varies depending on the position of the pressure application section 40. In addition, the thickness of the piezoelectric body can be made approximately constant, and the upper electrode 130 and the lower electrode 120 can be formed in parallel with the piezoelectric layer 140 of a constant thickness sandwiched therebetween. Such gap regions 144, voids 146, etc. can be easily formed by, for example, etching. Therefore, the position detection device 100 of the second configuration example for comparison can also be easily manufactured, and the position to which an external force is actually applied can be identified from among the positions to which multiple pressures are applied, without arranging multiple sensor elements.

[0055] As described above, the pressure sensor 110 to be compared outputs a detection signal whose maximum amplitude value differs depending on the position of the pressure application unit 40 to which the external force is applied. When the magnitude of the applied external force changes, the pressure sensor 110 outputs a detection signal whose maximum amplitude value differs according to the magnitude of the external force. Therefore, the pressure sensor 110 described above is a sensor that can accurately identify the pressure application unit 40 to which the external force is applied, as long as the magnitude of the applied external force is within a predetermined range.

[0056] For example, when a larger external force than normal is applied to the first pressure application unit 40A, the pressure sensor 110 may output a detection signal with a maximum amplitude value similar to the maximum amplitude value of the detection signal output when an external force of a normal magnitude is applied to the second pressure application unit 40B. In this case, the identification unit 170 identifies the pressure application unit 40 to which the external force is applied as the second pressure application unit 40B. In the pressure sensor 110, it is desirable to reduce such fluctuations in detection accuracy due to the magnitude of the external force. Therefore, next, a pressure sensor 110 that can reduce detection accuracy even when the magnitude of the external force varies will be described.

[0057] <First Configuration Example of Position Detection Device 100> Fig. 4 shows a first configuration example of the position detection device 100 according to this embodiment. In the position detection device 100 of the first configuration example, parts that operate in substantially the same manner as the comparative position detection device 100 shown in Fig. 2 are given the same reference numerals, and descriptions thereof will be omitted. In the position detection device 100 of the first configuration example, the pressure sensor 110 includes a first piezoelectric layer 210, an intermediate electrode 220, and a second piezoelectric layer 230, and the identification unit 170 includes an external force identification unit 240 and a position identification unit 250.

[0058] The first piezoelectric layer 210 is a portion where a piezoelectric body is formed on the lower electrode 120. The first piezoelectric layer 210 is desirably formed on the upper surface of the lower electrode 120. The piezoelectric body is made of the same material as the piezoelectric layer 140 described in FIG. 2. The first piezoelectric layer 210 is formed as a reference piezoelectric layer for generating a reference signal. The first piezoelectric layer 210 is formed of a piezoelectric body with a constant thickness. The first piezoelectric layer 210 may be formed to a predetermined thickness.

[0059] The intermediate electrode 220 is formed on the first piezoelectric layer 210. The intermediate electrode 220 is preferably formed on the upper surface of the first piezoelectric layer 210. The intermediate electrode 220 is preferably formed integrally with the first piezoelectric layer 210. The intermediate electrode 220 is formed of, for example, the same material as the lower electrode 120 and the upper electrode 130.

[0060] The second piezoelectric layer 230 is a portion on the intermediate electrode 220 where a piezoelectric body having a thickness different from that of the first piezoelectric layer 210 is formed. The second piezoelectric layer 230 is formed as a detection piezoelectric layer. In the detection piezoelectric layer, a piezoelectric body is formed such that the volume of the piezoelectric body per unit area varies depending on the position of the pressure application section 40 in a plane parallel to the substrate. In other words, the second piezoelectric layer 230 is a portion similar to the piezoelectric layer 140 described in FIG. 2.

[0061] The upper electrode 130 is formed on the second piezoelectric layer 230. The upper electrode 130 is desirably formed on the upper surface of the second piezoelectric layer 230. As described above, the pressure sensor 110 of the third configuration example is configured by adding the first piezoelectric layer 210 and the intermediate electrode 220, both of which have a constant thickness, to the pressure sensor 110 of the first configuration example for comparison.

[0062] The signal receiving unit 160 receives the first detection signal output from the lower electrode 120 and the intermediate electrode 220, and the second detection signal output from the intermediate electrode 220 and the upper electrode 130. The first detection signal is used as a reference signal. The second detection signal is the detection signal described in FIG.

[0063] The external force identifying unit 240 identifies the magnitude of the external force applied to the pressure applying unit 40 based on the first detection signal and the second detection signal received by the signal receiving unit 160. For example, the external force identifying unit 240 normalizes the second detection signal using the first detection signal as a reference signal. In this case, the external force identifying unit 240 normalizes the second detection signal by dividing the maximum amplitude value of the second detection signal by the maximum amplitude value of the first detection signal. The external force identifying unit 240 may normalize the second detection signal by dividing the effective value of the second detection signal by the effective value of the first detection signal.

[0064] In the second piezoelectric layer 230, the volume of the piezoelectric material per unit area varies depending on the position of the pressure application unit 40, and therefore, as described above, the amplitude value of the second detection signal varies depending on the position of the pressure application unit 40 to which the external force is applied. Also, the amplitude value of the second detection signal varies depending on the magnitude of the applied external force.

[0065] In contrast, since the first piezoelectric layer 210 has a substantially constant piezoelectric thickness, if the magnitude of the external force is substantially constant, the amplitude value of the first detection signal will be substantially constant even if the position of the pressure application unit 40 to which the external force is applied varies. On the other hand, the amplitude value of the first detection signal, like the amplitude value of the second detection signal, will vary depending on the magnitude of the applied external force.

[0066] For example, when an external force of magnitude F1 is applied to the first pressure application unit 40A, the maximum amplitude value of the first detection signal output by the pressure sensor 110 is H 11 , the maximum amplitude value of the second detection signal is H 21 In this case, the external force identification unit 240 determines H 21 / H 11 is the normalized magnitude of the external force.

[0067] In addition, the maximum amplitude value of the first detection signal output by the pressure sensor 110 when an external force of magnitude n·F1 is applied to the first pressure application unit 40A is defined as H 1n , the maximum amplitude value of the second detection signal is H 2n Here, n is a positive integer. In this case, an external force having a magnitude n times the magnitude F1 is applied to the first pressure application unit 40A, and the maximum amplitude value H 1n is n H 11 and the maximum amplitude value H 2n is n H 21 Therefore, the external force identification unit 240 determines the magnitude of the normalized external force as H 21 / H 11 It is possible to calculate a value that is approximately the same as

[0068] In this way, the external force identifying unit 240 normalizes the second detection signal using the first detection signal, and thereby can identify the normalized magnitude of the external force that is approximately the same when external forces of different magnitudes are applied to the same pressure application unit 40. Therefore, even if the magnitudes of the external forces applied to the pressure application unit 40 are different, the external force identifying unit 240 can identify the normalized magnitude of the external force that corresponds to the position of the pressure application unit 40 to which the external force is applied.

[0069] The storage unit 180 of the first configuration example stores a reference value of the magnitude of the normalized external force. The storage unit 180 stores, for example, pressure application unit data in which the positions of the multiple pressure application units 40 on a plane parallel to the substrate are associated with the reference value of the magnitude of the external force detected when pressure is applied to each of the pressure application units 40. The reference value of the magnitude of the external force may be a value obtained by subtracting an allowable error value from the average value of the normalized magnitude of the external force specified in advance, as in the example of FIG. 2, or may be a combination of a value obtained by subtracting an allowable error value from the average value and a value obtained by adding an allowable error value to the average value. The reference value of the normalized magnitude of the external force may be a value determined from a design value or the like.

[0070] The position identifying unit 250 identifies the position of the pressure application unit 40 to which the external force has been applied, based on the magnitude of the external force identified by the external force identifying unit 240 and the pressure application unit data stored in the memory unit 180. The position identifying unit 250 identifies the position of the pressure application unit 40 to which the external force has been applied, by comparing the normalized magnitude of the external force with a reference value. For example, the position identifying unit 250 identifies the position of the pressure application unit 40 corresponding to the set of reference values ​​in accordance with the normalized magnitude of the external force being within the range of the set of reference values.

[0071] As described above, even if the magnitude of the external force applied to the pressure application unit 40 fluctuates, the magnitude of the external force identified by the external force identifying unit 240 according to this embodiment is hardly affected by the fluctuation, so the position identifying unit 250 can accurately identify the position of the pressure application unit 40. Therefore, the position detection device 100 of the first configuration example can accurately identify the position to which the external force is actually applied among the multiple pressure application units 40, without arranging multiple sensor elements.

[0072] In the position detection device 100 of the first configuration example described above, the second piezoelectric layer 230, which is the piezoelectric layer for detection, is the same part as the piezoelectric layer 140 described in Fig. 2, but the present invention is not limited to this. Alternatively, the second piezoelectric layer 230 may be the same part as the piezoelectric layer 140 described in Fig. 3.

[0073] <Second Configuration Example of Position Detection Device 100> 5 shows a second configuration example of the position detection device 100 according to this embodiment. In the position detection device 100 of the second configuration example, the second piezoelectric layer 230, which is the detection piezoelectric layer of the pressure sensor 110b, is formed to a substantially constant thickness. In this case, the detection piezoelectric layer may have an area within a region corresponding to the pressure application unit 40 in a plane parallel to the substrate 50 that varies depending on the position of the pressure application unit 40.

[0074] The detection piezoelectric layer may have a plurality of piezoelectric regions corresponding to a plurality of pressure application sections 40, and gap regions 144 in which no piezoelectric body is formed may be provided between each of the plurality of piezoelectric regions and the other piezoelectric regions. Furthermore, the detection piezoelectric layer may have a plurality of voids 146 in which no piezoelectric body is formed, and the volume of the void 146 in the first piezoelectric region of the detection piezoelectric layer corresponding to the first pressure application section 40A may be different from the volume of the void 146 in the second piezoelectric region of the detection piezoelectric layer corresponding to the second pressure application section 40B different from the first pressure application section 40A.

[0075] As described above, even if the second piezoelectric layer 230, which is the detection piezoelectric layer, is formed to a substantially constant thickness, it is possible to form the volume of the piezoelectric material per unit area to vary depending on the position of the pressure application unit 40. As a result, the position detection device 100 of the second configuration example can also accurately identify the position of the pressure application unit 40 to which an external force is applied by using the first detection signal and the second detection signal, similar to the position detection device 100 of the first configuration example.

[0076] In the above first and second configuration examples of the position detection device 100, the detection piezoelectric layer is the second piezoelectric layer 230, but the present invention is not limited to this. The detection piezoelectric layer may be the first piezoelectric layer 210. In this case, the first piezoelectric layer 210 may be formed as a detection piezoelectric layer having a similar configuration to the piezoelectric layer 140 described in FIG. 2 or FIG. 3. Then, on the first piezoelectric layer 210, an intermediate electrode 220, a second piezoelectric layer 230 in which a piezoelectric having a constant thickness is formed, and an upper electrode 130 are provided as a reference piezoelectric layer for generating a reference signal.

[0077] In this case, since the second detection signal becomes the reference signal, the external force identifying unit 240 normalizes the first detection signal using the second detection signal as the reference signal, thereby identifying the magnitude of the external force applied to the pressure application unit 40. In this manner, even in the position detection device 100 in which the configurations of the first piezoelectric layer 210 and the second piezoelectric layer 230 are reversed in the position detection device 100 of the first and second configuration examples, the position to which the external force has actually been applied can be identified with high accuracy among the multiple pressure application units 40.

[0078] In the above first and second configuration examples of the position detection device 100, an example has been described in which the external force identification unit 240 identifies the magnitude of the external force by using one of the first and second detection signals as a reference signal and normalizing the other of the first and second detection signals, but the present invention is not limited to this. The external force identification unit 240 may identify the magnitude of the external force by, for example, calculating the difference between the first and second detection signals.

[0079] For example, when an external force of magnitude F1 is applied to the first pressure application unit 40A, the maximum amplitude value of the first detection signal output by the pressure sensor 110 is H 11 , the maximum amplitude value of the second detection signal is H 21 In this case, the external force identification unit 240 calculates the difference between the first detection signal and the second detection signal as (H 11 -H 21 ) is calculated.

[0080] The maximum amplitude value of the first detection signal output by the pressure sensor 110 when an external force of magnitude F1+ΔF is applied to the first pressure application unit 40A is defined as H 11 +ΔF ΔH 11 , the maximum amplitude value of the second detection signal is H 21 +ΔF ΔH 21 Let ΔH 11 and ΔH 21 indicates the ratio of the value at which the amplitude value changes corresponding to the change ΔF in the magnitude of the applied external force. In this case, the external force identification unit 240 calculates the difference between the first detection signal and the second detection signal as (H 11 -H 21 ) + ΔF (ΔH 11 -ΔH 21 ) is calculated.

[0081] When the difference between the thickness of the first piezoelectric layer 210 and the thickness of the second piezoelectric layer 230 corresponding to the position of the pressure applying unit 40 where the external force is applied is relatively small, (ΔH 11 -ΔH 21 ) can be approximated to zero. In this way, by calculating the difference between the first detection signal and the second detection signal, the external force identification unit 240 can obtain a substantially constant value (ΔH 11 -ΔH 21 ) can be calculated.

[0082] As described above, the external force identifying unit 240 can identify the difference between the first detection signal and the second detection signal when an external force of a specific magnitude F1 is applied to one pressure application unit 40 by calculating the difference between the first detection signal and the second detection signal when an external force of a specific magnitude F1 is applied to the one pressure application unit 40. As a result, the storage unit 180 stores the positions of the multiple pressure application units 40 on a plane parallel to the substrate, and a reference value of the difference between the first detection signal and the second detection signal detected when pressure is applied to each of the pressure application units 40. As a result, the position identifying unit 250 can identify the position of the pressure application unit 40 to which the external force is applied by comparing the identified difference between the first detection signal and the second detection signal with the reference value.

[0083] In the above first and second configuration examples of the position detection device 100, the external force identifying unit 240 operates to calculate a substantially constant value using the first detection signal and the second detection signal even if the external force applied to the pressure application unit 40 changes, but the present invention is not limited to this. Alternatively or in addition to this, the external force identifying unit 240 may identify the magnitude of the external force actually applied to the pressure application unit 40.

[0084] Here, the first piezoelectric layer 210 is a reference piezoelectric layer, and the second piezoelectric layer 230 is a detection piezoelectric layer. When the reference value of the external force is F0 and the reference external force F0 is applied to the first piezoelectric layer 210, the maximum amplitude value of the first detection signal (reference signal) output by the first piezoelectric layer 210 is H 10 Consider an example in which the maximum amplitude value H 10 is stored as a reference amplitude value in association with the reference external force F0. When the reference external force F0 is applied to the second piezoelectric layer 230, the maximum amplitude value of the second detection signal output by the second piezoelectric layer 230 is stored as H 20 Let us assume that.

[0085] When an external force F1 different from the reference external force F0 is applied to the pressure application unit 40, the maximum amplitude value of the reference signal output by the first piezoelectric layer 210 is H 11 The maximum amplitude of the second detection signal output by the second piezoelectric layer 230 is H 21 In this case, the external force identifying unit 240 uses the reference amplitude value H 10 and the maximum amplitude is H 11 The external force determination unit 240, for example, compares the reference amplitude value H 10 and maximum amplitude value H 11 The ratio of F0 to H is multiplied by the reference external force. 11 / H 10 By calculating this, the magnitude of the external force F1 can be determined.

[0086] The magnitude of the external force F1 is approximately the same as the magnitude of the external force applied to the second piezoelectric layer 230, so F1=F0·H 21 / H20 Therefore, the external force identification unit 240 determines that H 20 =H 21 F0 / F1(=H 10 H 21 / H 11 ) is calculated, the maximum amplitude H of the second detection signal output by the second piezoelectric layer 230 when the reference external force F0 is applied to the second piezoelectric layer 230 is calculated. 20 Here, the storage unit 180 stores such a maximum amplitude value H 20 may be stored as a reference amplitude value in association with the reference external force F0. In this way, the position specifying section 250 stores the reference amplitude value H 20 The position of the pressure application unit 40 corresponding to the pressure can be identified.

[0087] As described above, the position detection device 100 of the first and second configuration examples is provided with a reference piezoelectric layer in addition to a detection piezoelectric layer, and can accurately identify the position of the pressure application unit 40 by using two detection signals output from the detection piezoelectric layer and the reference piezoelectric layer. Note that the pressure sensor 110 is provided with a detection piezoelectric layer and a reference piezoelectric layer corresponding to the position of the pressure application unit 40, so that in the case of a normal pressure sensor 110, when an external force is applied to the pressure application unit 40, a first detection signal and a second detection signal with an amplitude value according to the magnitude of the external force are output.

[0088] On the other hand, one of the detection piezoelectric layer and the reference piezoelectric layer may have an abnormality such as a defect in the piezoelectric material, deterioration, a short circuit in the electrode, or a broken wire. In this case, even if an external force is applied to the pressure application unit 40, the amplitude value of the detection signal from the piezoelectric layer in which the abnormality occurs will be a value that is almost unrelated to the magnitude of the external force. Therefore, the external force identification unit 240 can also detect an abnormality in the pressure sensor 110 by comparing the first detection signal with the second detection signal.

[0089] The external force identification unit 240 identifies an abnormality in the pressure sensor 110, for example, when the ratio between the maximum amplitude value of the first detection signal and the maximum amplitude value of the second detection signal falls outside a predetermined range of values. This allows the position detection device 100 to identify the position of the pressure application unit 40 to which the external force has been applied, while identifying whether the pressure sensor 110 is normal or abnormal. In this way, in the case of the position detection device 100 that identifies whether the pressure sensor 110 is normal or abnormal, the pressure sensor 110 may be configured to include one pressure application unit 40. In this case, the position detection device 100 can identify whether an external force has been applied to the pressure application unit 40, while identifying whether the pressure sensor 110 is normal or abnormal.

[0090] Alternatively, the pressure sensor 110 may be configured such that the pressure sensor 110 of the comparative position detection device 10 shown in Fig. 1 is further provided with an intermediate electrode 220 and a reference piezoelectric layer. In this case, the position detection device 100 can identify the position where the external force is applied to the pressure application unit 40 while identifying whether the pressure sensor 110 is normal or abnormal. As described above, the position detection device 100 using the comparative example of Figs. 2 and 3 is even better than the position detection device 100 using the comparative example of Fig. 1 in that it can detect the position of the pressure application unit 40 to which pressure is actually applied, among the multiple pressure application units 40, without arranging multiple sensor elements 60 or the like.

[0091] <Method of Manufacturing Pressure Sensor 110 of First Configuration Example> The pressure sensor 110 of the first configuration example can be manufactured by any method, but for example, it can be manufactured by a method of screen printing a piezoelectric material as follows: A mask pattern is prepared in which areas other than areas corresponding to the shapes of the first piezoelectric region 141, the second piezoelectric region 142, and the third piezoelectric region 143 are masked.

[0092] After printing a piezoelectric material with a substantially uniform thickness on the upper surface of the lower electrode 120, the printed piezoelectric material is sintered. An intermediate electrode 220 is formed on the upper surface of the first piezoelectric layer 210 thus formed. With a mask pattern placed on the intermediate electrode 220, a piezoelectric material is printed on the first piezoelectric region 141, the second piezoelectric region 142, and the third piezoelectric region 143, and then the printed piezoelectric material is sintered. After the piezoelectric material has cooled to a predetermined temperature, the piezoelectric material is printed on the second piezoelectric region 142 and the third piezoelectric region 143. The thickness of the printed piezoelectric material is, for example, the same as the thickness of the piezoelectric material printed on the first piezoelectric region 141. The printed piezoelectric material is sintered, and after the piezoelectric material has cooled to a predetermined temperature, the piezoelectric material is printed on the third piezoelectric region 143. Then, the printed piezoelectric material is sintered. An upper electrode 130 is formed on the upper surface of the second piezoelectric layer 230 thus formed, and wiring 90 is connected to the lower electrode 120, the intermediate electrode 220, and the upper electrode 130. By the above procedure, it is possible to manufacture a pressure sensor 110 in which the thickness of the second piezoelectric layer 230 varies depending on the position.

[0093] <Method of Manufacturing Pressure Sensor 110b of Second Configuration Example> The pressure sensor 110b of the second configuration example can also be manufactured by screen printing the piezoelectric material in the same manner as the above-mentioned manufacturing method. In this case, the shapes of the areas in the mask pattern corresponding to the first piezoelectric material region 141, the second piezoelectric material region 142, and the third piezoelectric material region 143 correspond to the shapes of the first piezoelectric material region 141, the second piezoelectric material region 142, and the third piezoelectric material region 143 in FIG.

[0094] After printing a piezoelectric material with a substantially uniform thickness on the upper surface of the lower electrode 120, the printed piezoelectric material is sintered. An intermediate electrode 220 is formed on the upper surface of the first piezoelectric layer 210 thus formed. With a mask pattern placed on the intermediate electrode 220, a piezoelectric material is printed on the first piezoelectric region 141, the second piezoelectric region 142, and the third piezoelectric region 143 to form a second piezoelectric layer 230, on which an upper electrode 130 is formed, and wiring 90 is connected to the lower electrode 120, the intermediate electrode 220, and the upper electrode 130, thereby manufacturing the pressure sensor 110b.

[0095] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0096] 10 Position detection device 20 Pressure Sensor 30 Signal Processing Section 40 Pressure application section 50 Substrates 60 Sensor element 62 Lower electrode 64 Upper electrode 66 Piezoelectric layer 70 Base layer 80 Protective film 90 Wiring 100 Position detection device 110 Pressure Sensor 120 Lower electrode 130 Upper electrode 140 Piezoelectric layer 141 First Piezoelectric Region 142 Second Piezoelectric Region 143 Third Piezoelectric Region 144 Gap Area 146 Cavity 150 Signal Processing Section 160 Signal receiving unit 170 Specific section 180 Storage section 210 First piezoelectric layer 220 Intermediate electrode 230 Second piezoelectric layer 240 External force identification part 250 Location identification part

Claims

1. A substrate; a lower electrode formed on a substrate; a first piezoelectric layer having a piezoelectric body formed on the lower electrode; an intermediate electrode formed on the first piezoelectric layer; a second piezoelectric layer on which a piezoelectric body having a thickness different from that of the first piezoelectric layer is formed on the intermediate electrode; an upper electrode formed on the second piezoelectric layer; a plurality of pressure application units formed on the upper electrode and to which pressure is applied from an outside; a signal receiving unit that receives a first detection signal output from the lower electrode and the intermediate electrode and a second detection signal output from the intermediate electrode and the upper electrode; an external force identification unit that identifies a magnitude of the external force applied to the pressure application unit based on the first detection signal and the second detection signal received by the signal receiving unit; Equipped with one of the first piezoelectric layer and the second piezoelectric layer is formed such that a volume of the piezoelectric body per unit area varies depending on a position of the pressure application portion in a plane parallel to the substrate, A pressure sensor, wherein at least one of the first piezoelectric layer and the second piezoelectric layer is formed of a piezoelectric material having a constant thickness.

2. A substrate; a lower electrode formed on a substrate; a first piezoelectric layer having a piezoelectric body formed on the lower electrode; an intermediate electrode formed on the first piezoelectric layer; a second piezoelectric layer on which a piezoelectric body having a thickness different from that of the first piezoelectric layer is formed on the intermediate electrode; an upper electrode formed on the second piezoelectric layer; a pressure application unit formed on the upper electrode and to which pressure is applied from an outside; a signal receiving unit that receives a first detection signal output from the lower electrode and the intermediate electrode and a second detection signal output from the intermediate electrode and the upper electrode; an external force identification unit that identifies a magnitude of the external force applied to the pressure application unit based on the first detection signal and the second detection signal received by the signal receiving unit; Equipped with At least one of the first piezoelectric layer and the second piezoelectric layer is formed of a piezoelectric material having a constant thickness, the external force identification unit normalizes the second detection signal using the first detection signal as a reference signal, or normalizes the first detection signal using the second detection signal as a reference signal, thereby identifying a normalized magnitude of the external force applied to the pressure application unit. Pressure sensor.

3. a plurality of pressure application units are formed on the upper electrode, one of the first piezoelectric layer and the second piezoelectric layer is formed to have a constant piezoelectric thickness as a reference piezoelectric layer for generating the reference signal; the other of the first piezoelectric layer and the second piezoelectric layer, which is different from the reference piezoelectric layer, is formed as a detection piezoelectric layer, the detection piezoelectric layer is formed such that a volume of the piezoelectric body per unit area varies depending on a position of the pressure application portion in a plane parallel to the substrate, the signal receiving unit receives the first detection signal and the second detection signal generated based on a pressure application unit to which an external force is applied among the plurality of pressure application units. The pressure sensor according to claim 2.

4. The pressure sensor according to claim 3 , wherein a thickness of the detection piezoelectric layer varies depending on a position of the pressure application portion.

5. 5. The pressure sensor according to claim 3, wherein an area of ​​the detection piezoelectric layer within a region corresponding to the pressure application portion in a plane parallel to the substrate varies depending on a position of the pressure application portion.

6. The pressure sensor according to any one of claims 3 to 5, wherein the detection piezoelectric layer has a plurality of piezoelectric regions corresponding to a plurality of the pressure application sections, and a gap region in which no piezoelectric material is formed is provided between each of the plurality of piezoelectric regions and other piezoelectric regions.

7. The detection piezoelectric layer has a plurality of voids in which no piezoelectric material is formed, a volume of the void portion of a first piezoelectric region of the detection piezoelectric layer corresponding to a first pressure application portion is different from a volume of the void portion of a second piezoelectric region of the detection piezoelectric layer corresponding to a second pressure application portion different from the first pressure application portion; A pressure sensor according to any one of claims 3 to 6.

8. The pressure sensor according to claim 1 , a storage unit configured to store pressure application unit data in which the positions of the pressure application units in a plane parallel to the substrate are associated with reference values ​​of the magnitudes of external forces detected when pressure is applied to the pressure application units; a position specifying unit that specifies a position of the pressure application unit to which the external force is applied based on the magnitude of the external force specified by the external force specifying unit and the pressure application unit data; Equipped with Position detection device.

Images