JP2022100756A - Pressure sensor and position detection device - Google Patents

Abstract

To specify a position where external force is actually applied from among a plurality of pressure applied positions, without the need for arranging a plurality of sensor elements.SOLUTION: A pressure sensor comprises: a substrate; a lower electrode formed on the substrate; a piezoelectric layer in which a piezoelectric material is formed on the lower electrode; an upper electrode formed on the piezoelectric layer; and a plurality of pressure applied parts which are formed on the upper electrode, and to which pressure is applied from the outside. In the piezoelectric layer, the piezoelectric material is formed such that the volume of the piezoelectric material per unit area differs depending on the position of a pressure applied part on a plane parallel to the substrate.SELECTED DRAWING: Figure 2

Description

The present invention relates to a pressure sensor and a position detection device.

Conventionally, a sensor element using a piezoelectric effect in which a piezoelectric body is sandwiched between two electrodes and an external force is applied so as to distort the piezoelectric body to generate a voltage between the two electrodes is known. A position detection device that detects a position to which an external force is applied by arranging a plurality of such sensor elements is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2018-163531

In such a position detection device, a sensor element is arranged at 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.

Therefore, the present invention has been made in view of these points, and it is possible to specify a position where an external force is actually applied from among a plurality of pressure application positions without arranging a plurality of sensor elements. With the goal.

In the first aspect of the present invention, on the substrate, the lower electrode formed on the substrate, the piezoelectric layer on which the piezoelectric body is formed on the lower electrode, and the piezoelectric layer. The piezoelectric layer comprises a formed upper electrode and a plurality of pressure applying portions formed on the upper electrode and to which pressure is applied from the outside, and the piezoelectric layer is a unit in a plane parallel to the substrate. Provided is a pressure sensor in which the piezoelectric body is formed so that the volume of the piezoelectric body per area differs depending on the position of the pressure application portion.

The thickness of the piezoelectric layer may differ depending on the position of the pressure applying portion.
The area of the piezoelectric layer in the region corresponding to the pressure applying portion on the plane parallel to the substrate may differ depending on the position of the pressure applying portion.

The piezoelectric layer has a plurality of piezoelectric regions corresponding to the plurality of pressure application portions, and the piezoelectric body is formed between each of the plurality of piezoelectric regions and another piezoelectric region. A gap area that is not provided may be provided.

The piezoelectric layer is formed with a plurality of voids in which the piezoelectric is not formed, and the volume of the voids in the first piezoelectric region of the piezoelectric layer corresponding to the first pressure application portion. May be different from the volume of the void portion of the second piezoelectric region of the piezoelectric layer corresponding to the second pressure application portion different from the first pressure application portion.

The upper electrode and the lower electrode may be formed in parallel with the piezoelectric layer having a certain thickness interposed therebetween.

The pressure sensor of the first aspect, the signal receiving unit that receives the detection signals output from the upper electrode and the lower electrode, the positions of a plurality of the pressure applying units on a plane parallel to the substrate, and the pressure application. A storage unit that stores pressure application unit data associated with a reference value of the detection signal when pressure is applied to each unit, and the detection signal received by the signal reception unit and the pressure application unit data. Based on this, the present invention provides a position detecting device including a specific unit for specifying the position of the pressure application unit to which an external force is applied.

According to the present invention, there is an effect that the position where the external force is actually applied can be specified from the plurality of pressure application positions without arranging the plurality of sensor elements.

A configuration example of the position detection device 10 to be compared is shown. The first configuration example of the position detection apparatus 100 which concerns on this embodiment is shown. A second configuration example of the position detection device 100 according to the present embodiment is shown.

<Configuration example of the conventional position detection device 10>
FIG. 1 shows a configuration example of the position detection device 10 to be compared. In this embodiment, three orthogonal axes are shown as X-axis, Y-axis, and 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 a wiring 90.

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 of 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. The pressure is applied to the pressure applying unit 40 by, for example, an operation by a user or the like. As an example, the pressure applying portion 40 is pressed by the fingertip of the user. The pressure applying portion 40 is formed in the shape of, for example, a push button or a key button. Instead of this, the plurality of pressure application portions 40 may be a plurality of regions divided by printing or the like on the upper surface of an elastic plate-shaped or film-shaped member. The pressure applying portion 40 is attached to, for example, a housing (not shown) or the like.

The substrate 50 has a surface substantially parallel to the XY surface, and a member such as a sensor element 60 is formed on the surface. It is desirable that the substrate 50 is a member for maintaining the strength of the position detecting device 10. The substrate 50 is made of, for example, a material that can be bent. In this case, the substrate 50 is a PEN (polyethylene naphthalate) film, a PET (polyethylene terephthalate) film, a flexible substrate, or the like.

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

The lower electrode 62 and the upper electrode 64 are made of a conductive material. It is desirable 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 so as to sandwich the piezoelectric layer 66.

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

The protective film 80 is formed so as to cover the plurality of sensor elements 60. The protective film 80 is a resin or the like. The protective film 80 is, for example, a polymer such as parylene. The pressure applying portion 40 is provided on the protective film 80. The pressure applying portion 40 may be provided so as to come into contact with the protective film 80 in a non-pressed state, and instead, the pressure applying portion 40 may be provided so as to have a gap between the pressure applying portion 40 and the protective film 80. May be good.

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 the voltage generated from the sensor element 60 and identifies the sensor element 60 to which the pressure is applied among the plurality of sensor elements 60. Further, the signal processing unit 30 can specify the pressure application unit 40 corresponding to the specified sensor element 60 as the pressure application unit 40 to which an external force is applied.

As described above, in the pressure sensor 20, the sensor element 60 is arranged corresponding to the position of the pressure applying portion 40 so that the pressure is applied to the piezoelectric layer 66 when the pressure applying portion 40 is pressed. Then, the sensor element 60 generates a voltage corresponding to the pressure applied to the piezoelectric layer 66 between the lower electrode 62 and the upper electrode 64 due to the piezoelectric effect.

The sensor element 60 generates a voltage larger than the steady state voltage when the user presses the pressure application unit 40 with a finger, for example, as in the example of the detection waveform shown in FIG. Further, the sensor element 60 generates a voltage smaller than the voltage in the steady state when the user releases the pressure application unit 40 from the state where the user presses the pressure application unit 40 with the finger. The signal processing unit 30 identifies the sensor element 60 to which the pressure is applied, for example, by detecting the maximum amplitude value of such a detection waveform.

The above position detection device 10 can function as an input device for detecting 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, in the signal processing unit 30, the first pressure application unit 40A at the position corresponding to the sensor element 60A is pressed in response to the generation of a predetermined voltage value from the wiring 90 connected to the sensor element 60A. Can be detected. The signal processing unit 30 outputs the detected information of the pressure applying unit 40 to an external circuit, device, or the like.

As a result, the position detection device 10 is configured as an input device such as a touch panel, a numeric keypad, and a keyboard. Since the position detection device 10 utilizes the piezoelectric effect, it is possible to reduce erroneous detection even if water droplets or dust intervene, as compared with an input device that utilizes capacitance.

In such a position detecting device 10, there may be a case where it is desired to improve the position detection resolution, a case where it is desired to increase the number of pressure applying units 40 which can be input, and the like. In this case, the sensor element 60 must be arranged at each position where the pressure of the pressure sensor 20 is desired 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 circuit of the signal processing unit 30, and the like become complicated, and the manufacturing, maintenance, inspection, and the like of the position detection device 10 become complicated. It could be difficult. Therefore, the position detection device according to the present embodiment can detect the position of the pressure application unit 40 to which the pressure is actually applied from among the plurality of pressure application units 40 without arranging the plurality of sensor elements 60 and the like. do.

<Structure example of position detection device 100 according to this embodiment>
FIG. 2 shows a first configuration example of the position detection device 100 according to the present embodiment. In the position detection device 100 according to the present embodiment, substantially the same operation as that of the position detection device 10 to be compared shown in FIG. 1 is designated by the same reference numerals, and duplicate description 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.

The lower electrode 120 is formed on the substrate 50. FIG. 2 shows an example in which the lower electrode 120 is formed on the upper surface of the base layer 70. It is desirable that the lower electrode 120 is integrally formed. The upper electrode 130 is formed on the piezoelectric layer 140. It is desirable that the upper electrode 130 is formed on the upper surface of the piezoelectric layer 140. It is desirable that the upper electrode 130 is integrally formed. The lower electrode 120 and the upper electrode 130 are made of a conductive material.

The piezoelectric layer 140 is a portion where the piezoelectric body is formed on the lower electrode 120. It is desirable that the piezoelectric layer 140 is formed on the upper surface of the lower electrode 120. The piezoelectric material is a material having a ferroelectricity having a piezoelectric effect. The piezoelectric material is, for example, a polymer such as PVDF (polyvinylidene fluoride) or a piezoelectric ceramic such as PZT (lead zirconate titanate).

As described above, in the position detection device 100 according to the present embodiment, the lower electrode 120, the upper electrode 130, and the piezoelectric layer 140 are formed in place of the plurality of sensor elements 60 of the position detection device 10 to be compared. There is. In other words, in the position detecting device 100, the common lower electrode 120 and the common upper electrode 130 are formed so as to sandwich the piezoelectric layer 140. Then, the pressure applying portion 40 is formed on the upper electrode 130 via the protective film 80.

The piezoelectric layer 140 is formed on a plane (XY plane) substantially parallel to the substrate 50 so that the volume of the piezoelectric layer per unit area differs depending on the position of the pressure applying portion 40. FIG. 2 shows an example in which the thickness of the piezoelectric layer 140 differs depending on the position of the pressure applying portion 40. In the piezoelectric effect of the piezoelectric layer 140, even if the same pressure is applied to the piezoelectric body, the voltage generated differs depending on the volume of the piezoelectric body to which the pressure is applied.

For example, when an external force is applied to the first pressure application unit 40A, a part of the piezoelectric layer 140 to which pressure is applied corresponding to the first pressure application unit 40A directly under the first pressure application unit 40A is the first piezoelectric layer. The body area is 141. Further, a part of the piezoelectric layer 140 in which an external force is applied to the second pressure applying portion 40B and pressure is applied corresponding to the second pressure applying portion 40B directly under the second pressure applying portion 40B is part of the second piezoelectric body region 142. And. Similarly, a part of the piezoelectric layer 140 to which pressure is applied when an external force is applied to the third pressure applying portion 40C is referred to as a third piezoelectric region 143.

In the case of FIG. 2, since the thickness of the first piezoelectric region 141 in the direction perpendicular to the substrate 50 (Z-axis direction) is formed thinner than the thickness of the second piezoelectric region 142, the first piezoelectric region is formed. The volume of 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.

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, piezoelectric is obtained when an external force of a certain magnitude is applied to each of the first pressure application unit 40A, the second pressure application unit 40B, and the third pressure application unit 40C. The voltages generated by the body 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 applying portion 40A is such that an external force having substantially the same magnitude as the external force is applied to the second pressure applying portion 40B. In addition, it is smaller than the magnitude of the voltage generated from the second piezoelectric region 142. Therefore, by detecting the value of the voltage generated in the common lower electrode 120 and the upper electrode 130, it is possible to determine to which pressure application unit 40 the external force is applied.

The wiring 90 transmits the voltage generated in the lower electrode 120 and the upper electrode 130 to the signal processing unit 150 as a detection signal in this way. The signal processing unit 150 identifies the pressure application unit 40 to which an external force is applied based on the waveform (for example, amplitude) of the detection signal output from the pressure sensor 110. The signal processing unit 150 includes a signal receiving unit 160, a specific unit 170, and a storage unit 180.

The signal receiving unit 160 receives the detection signal 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, and the like, and converts the received detection signal into a digital signal. The signal receiving unit 160 supplies the converted digital signal to the specific unit 170.

The specifying unit 170 identifies the position of the pressure applying unit 40 to which an external force is applied based on the detection signal received by the signal receiving unit 160 and the pressure applying unit data. The pressure application unit data is data in which the positions of the plurality of pressure application units 40 on the plane parallel to the substrate 50 and the reference value of the detection signal when the pressure is applied to the pressure application unit 40 are associated with each other. ..

For example, the average value of the maximum amplitude values 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 permissible value of the error from the average value. Similarly, the reference value ST2 of the detection signal corresponding to the second pressure application unit 40B is the average value of the maximum amplitude values of the voltage generated from the second piezoelectric region 142 by pressing the second pressure application unit 40B with a finger. It is a value (V2ave-ΔV) obtained by subtracting the allowable value of the error. Further, the reference value ST3 of the detection signal corresponding to the third pressure application unit 40C is also V3ave-ΔV.

In this case, in the specific unit 170, for example, when the maximum amplitude value of the detection signal is smaller than the reference value ST2 and becomes equal to or higher than the reference value ST1, the pressure application unit 40 to which an external force is applied is the first pressure. It is specified that it is the application unit 40A. Similarly, in the specific unit 170, the pressure application unit 40 to which an external force is applied is the second pressure application unit according to the fact that the maximum amplitude value of the detection signal is smaller than the reference value ST3 and becomes the reference value ST2 or more. Identify that it is 40B. Further, the specific unit 170 may specify that the pressure application unit 40 to which an external force is applied is the third pressure application unit 40C according to the fact that the maximum amplitude value of the detection signal becomes the reference value ST3 or more. ..

Instead of this, as the reference value of the detection signal, two values indicating the range of the voltage value may be set for one pressure application unit 40. For example, the reference value of the detection signal corresponding to the first pressure application unit 40A is ST1m (V1ave-ΔV), which is the average value minus the error tolerance, and ST1p (V1ave + ΔV), which is the average value plus the error tolerance. ).

In this case, in the specific unit 170, for example, when the maximum amplitude value of the detection signal is smaller than the reference value ST1p and becomes the reference value ST1m or more, the pressure application unit 40 to which an external force is applied is the first pressure. It is specified that it is the application unit 40A. The specific unit 170 more accurately identifies the pressure application unit 40 to which an external force is applied by using the reference value determined by the statistical method or the reference value determined from the design value or the like. be able to.

The specific unit 170 supplies, for example, information on the position where the specified external force is applied to an external circuit, device, or the like. Further, the specific unit 170 may display information on the position where the specified external force is applied on the display unit or the like. The specific unit 170 may store the information of the position where the specified external force is applied in the storage unit 180. Such a specific unit 170 is, for example, a CPU or the like.

The storage unit 180 stores the pressure application unit data in which the positions of the plurality of pressure application units 40 and the reference value of the detection signal are associated with each other. The storage unit 180 may store set values, threshold values, parameters, and the like used by the specific unit 170 for operation. When the CPU or the like operates as at least a part of the specific unit 170, the storage unit 180 may store information on a program executed by the CPU or the like. Further, the storage unit 180 may store various information including a database referred to when the program is executed.

As an example, the storage unit 180 includes a ROM (Read Only Memory) for storing a BIOS (Basic Input Output System) and the like, and a RAM (Random Access Memory) as a work area. As a result, the CPU and the like function as the specific unit 170 by executing the program stored in the storage unit 180.

As described above, in the pressure sensor 110 according to the present embodiment, since the volume per unit area of the piezoelectric body of the piezoelectric layer 140 differs depending on the position of the pressure applying portion 40, the detection generated when an external force is applied is detected. The maximum amplitude value of the signal differs depending on the position of the pressure application unit 40. Therefore, the position detection device 100 compares the maximum amplitude value of the detection signal of the pressure sensor 110 with the plurality of reference values, and the position of the pressure application unit 40 corresponding to the region of the piezoelectric layer 140 in which the detection signal is generated. Can be identified.

The pressure sensor 110 having such a piezoelectric layer 140 can have a simple configuration using a common lower electrode 120 and an upper electrode 130 that sandwich 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. Further, the position detection device 100 simply converts the detection signals output from the common lower electrode 120 and the upper electrode 130 into digital signals and digitally processes them, and an external force is actually applied from the plurality of pressure application units 40. The position of the pressure application unit 40 can be easily specified.

In the pressure sensor 110 according to the present embodiment described above, an example in which the thickness of the piezoelectric layer 140 differs depending on the position of the pressure applying portion 40 has been described, but the present invention is not limited thereto. In the pressure sensor 110, the volume per unit area of the piezoelectric body of the piezoelectric layer 140 may differ depending on the position of the pressure applying portion 40, and the piezoelectric layer 140 has the pressure applying portion 40 on a surface parallel to the substrate 50. The area in the region corresponding to the above may be formed so as to differ depending on the position of the pressure applying portion 40.

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 applying portion 40A is larger than the area of the second piezoelectric region 142 corresponding to the second pressure applying portion 40B. May be formed so as to be smaller. Similarly, in a plan view, the area of the second piezoelectric region 142 corresponding to the second pressure applying portion 40B is formed to be smaller than the area of the third piezoelectric region 143 corresponding to the third pressure applying portion 40C. It may have been done.

Thereby, the volume per unit area of the piezoelectric body of the piezoelectric layer 140 can be made different depending on the position of the pressure applying portion 40. The thickness of the piezoelectric layer 140 in the vertical direction of the substrate 50 may be formed to be substantially constant. In this case, the upper electrode 130 and the lower electrode 120 are formed substantially in parallel with the piezoelectric layer 140 having a substantially constant thickness interposed therebetween. Since the upper electrode 130 and the lower electrode 120 do not have a stepped portion, they are easy to manufacture, and defects that adversely affect the electrical characteristics due to step breakage or the like can be less likely to occur.

The plurality of piezoelectric regions of the piezoelectric layer 140 may be separated and formed by gaps or the like. Further, the plurality of piezoelectric regions of the piezoelectric layer 140 may be formed so that their volumes differ depending on the voids and the like. The position detection device 100 having such a pressure sensor 110a will be described below.

FIG. 3 shows a second configuration example of the position detection device 100 according to the present embodiment. The piezoelectric layer 140 included in the pressure sensor 110a of the second configuration example has a plurality of piezoelectric regions corresponding to the plurality of pressure application portions 40, and each of the plurality of piezoelectric regions and another piezoelectric region An example is shown in which a gap region 144 in which a piezoelectric body is not formed is provided between the two. By separating the plurality of piezoelectric regions in this way, it is possible to prevent pressure from being applied to adjacent piezoelectric regions when pressure is applied to one piezoelectric region, and the noise component of the detection signal is reduced. can do.

Further, the piezoelectric layer 140 is further formed with a plurality of void portions 146 in which the piezoelectric body is not formed. The volume of the void portion 146 of the first piezoelectric region 141 of the piezoelectric layer 140 corresponding to the first pressure applying portion 40A is the piezoelectric corresponding to the second pressure applying portion 40B different from the first pressure applying portion 40A. The piezoelectric layer 140 is formed so as to be different from the volume of the gap portion 146 of the second piezoelectric region 142 of the body layer 140.

Thereby, the piezoelectric layer 140 can be formed so that the volume per unit area of the piezoelectric body differs depending on the position of the pressure applying portion 40. Further, the thickness of the piezoelectric body can be made substantially constant, and the upper electrode 130 and the lower electrode 120 can be formed in parallel with the piezoelectric layer 140 having a constant thickness interposed therebetween. Such a gap region 144, a gap portion 146, and the like can be easily formed by, for example, etching. Therefore, the position detection device 100 of the second configuration example can also be easily manufactured, and an external force is actually applied from the position where a plurality of pressures are applied without arranging a plurality of sensor elements. The position can be specified.

<Manufacturing method of pressure sensor 110>
The method for manufacturing the pressure sensor 110 is arbitrary, but it can be manufactured by, for example, the method of screen-printing the piezoelectric body as follows. A mask pattern that masks a region other than the region corresponding to the shape of the first piezoelectric region 141, the second piezoelectric region 142, and the third piezoelectric region 143 is prepared.

With the mask pattern placed on the lower electrode 120, the 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 has cooled to a predetermined temperature, the piezoelectric is printed on the second piezoelectric region 142 and the third piezoelectric region 143. The thickness of the piezoelectric body printed at this time is, for example, the same as the thickness of the piezoelectric body printed in the first piezoelectric body region 141. The printed piezoelectric body is sintered, and after the piezoelectric body has cooled to a predetermined temperature, the piezoelectric body is printed on the third piezoelectric body region 143. Then, the printed piezoelectric body is sintered. The upper electrode 130 is formed on the piezoelectric layer 140 thus formed, and the wiring 90 is connected to the lower electrode 120 and the upper electrode 130. By the above procedure, the pressure sensor 110 having a different thickness of the piezoelectric layer depending on the position can be manufactured.

<Manufacturing method of pressure sensor 110a>
Like the pressure sensor 110, the pressure sensor 110a can also be manufactured by a method of screen-printing a piezoelectric body. When the pressure sensor 110a is manufactured, the shape of the region corresponding to the first piezoelectric region 141, the second piezoelectric region 142, and the third piezoelectric region 143 in the mask pattern is the first piezoelectric region 141, the first in FIG. It corresponds to the shapes of the 2 piezoelectric region 142 and the 3rd piezoelectric region 143. With the mask pattern placed on the lower electrode 120, the upper electrode 130 is placed on the piezoelectric layer 140 formed by printing a piezoelectric material on the first piezoelectric region 141, the second piezoelectric region 142, and the third piezoelectric region 143. The pressure sensor 110a can be manufactured by forming and connecting the wiring 90 to the lower electrode 120 and the upper electrode 130.

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 can be made within the scope of the gist. be. For example, all or part of the device can be functionally or physically distributed / integrated in any unit. Also included in the embodiments of the present invention are new embodiments resulting from any combination of the plurality of embodiments. The effect of the new embodiment produced by the combination has the effect of the original embodiment together.

10 Position detection device 20 Pressure sensor 30 Signal processing unit 40 Pressure application unit 50 Substrate 60 Sensor element 62 Lower electrode 64 Upper electrode 66 Piezoelectric layer 70 Underlayer 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 region 146 Void portion 150 Signal processing unit 160 Signal receiving unit 170 Specific unit 180 Storage unit

Claims (7)

With the board
The lower electrode formed on the substrate and
A piezoelectric layer in which a piezoelectric body is formed on the lower electrode,
The upper electrode formed on the piezoelectric layer and
It is formed on the upper electrode and includes a plurality of pressure application portions to which pressure is applied from the outside.
The piezoelectric layer is formed so that the volume of the piezoelectric layer per unit area differs depending on the position of the pressure application portion on a surface parallel to the substrate.
Pressure sensor. The pressure sensor according to claim 1, wherein the thickness of the piezoelectric layer varies depending on the position of the pressure applying portion. The pressure sensor according to claim 1 or 2, wherein the area of the piezoelectric layer in a region corresponding to the pressure applying portion on a surface parallel to the substrate differs depending on the position of the pressure applying portion. The piezoelectric layer has a plurality of piezoelectric regions corresponding to the plurality of pressure application portions, and the piezoelectric body is formed between each of the plurality of piezoelectric regions and another piezoelectric region. The pressure sensor according to any one of claims 1 to 3, wherein a gap region is provided. The piezoelectric layer is formed with a plurality of voids in which the piezoelectric is not formed.
The volume of the gap portion of the first piezoelectric region of the piezoelectric layer corresponding to the first pressure application portion is the first of the piezoelectric layer corresponding to the second pressure application portion different from the first pressure application portion. 2 It is different from the volume of the void portion of the piezoelectric region.
The pressure sensor according to any one of claims 1 to 4. The pressure sensor according to claim 5, wherein the upper electrode and the lower electrode are formed in parallel with the piezoelectric layer having a certain thickness interposed therebetween. The pressure sensor according to any one of claims 1 to 6.
A signal receiving unit that receives the detection signal output from the upper electrode and the lower electrode, and
A storage unit that stores pressure application unit data in which the positions of a plurality of pressure application units on a surface parallel to the substrate and the reference value of the detection signal when pressure is applied to the pressure application units are associated with each other. When,
A specific unit for specifying the position of the pressure application unit to which an external force is applied is provided based on the detection signal received by the signal reception unit and the pressure application unit data.
Position detector.

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