Sensor device

Abstract

To prevent neighboring piezoelectric elements from short-circuiting.SOLUTION: A sensor device includes: a substrate 10 having a sensor region 2 and a dummy region 3 surrounding the sensor region 2; a plurality of lower electrodes 21 provided in the sensor region 2 of the substrate 10; a plurality of first conductive adhesive layers 22 respectively provided on the plurality of lower electrodes 21; a plurality of dummy electrodes 31 provided in the dummy region 3 of the substrate 10, arranged to surround the plurality of lower electrodes 21, and not used as sensors; a plurality of second conductive adhesive layers 32 respectively provided on the plurality of dummy electrodes 31; a dielectric layer 11 provided on the plurality of first conductive adhesive layers 22 and the plurality of second conductive adhesive layers 32; and an upper electrode 12 provided on the dielectric layer 11 and configured to overlap the plurality of lower electrodes 21 and the plurality of dummy electrodes 31 in a plan view. The plurality of second conductive adhesive layers 32 have a same thickness as the plurality of first conductive adhesive layers 22.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sensor device including, for example, a piezoelectric element. [Background technology]

[0002] Piezoelectric sensors that utilize the piezoelectric effect are known. A piezoelectric sensor is a sensor device capable of outputting an electric signal in response to pressure applied to a piezoelectric body. Patent Document 1 discloses a piezoelectric sensor in which an organic piezoelectric film is provided on a plurality of electrodes arranged in a matrix. In Patent Document 1, a plurality of electrodes made of silver paste are formed in a matrix on an insulating film by using a screen printing method, an organic piezoelectric film is attached on the plurality of electrodes, and a common electrode is formed on the organic piezoelectric film by using a vapor deposition or sputtering method.

[0003] When an organic piezoelectric film is laminated onto a plurality of electrodes arranged in a matrix, the peripheral edge of the organic piezoelectric film may bend downward. In this case, the distance between the organic piezoelectric film and the substrate on which the plurality of electrodes are formed at the peripheral edge of the organic piezoelectric film may be narrower than the distance at the center of the organic piezoelectric film. In the region where the distance between the organic piezoelectric film and the substrate is narrow, capillary action (ink induction) occurs in the electrode made of silver paste, causing the electrode pattern to collapse. This may cause adjacent electrodes to short out. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-27270 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a sensor device capable of preventing adjacent piezoelectric elements from shorting out. [Means for solving the problem]

[0006] According to a first aspect of the present invention, there is provided a sensor device comprising: a substrate having a sensor region and a dummy region surrounding the sensor region; a plurality of lower electrodes provided in the sensor region of the substrate; a plurality of first conductive adhesive layers respectively provided on the plurality of lower electrodes; a plurality of dummy electrodes provided in the dummy region of the substrate, arranged to surround the plurality of lower electrodes, and not used as sensors; a plurality of second conductive adhesive layers respectively provided on the plurality of dummy electrodes; a dielectric layer provided on the plurality of first conductive adhesive layers and the plurality of second conductive adhesive layers; and an upper electrode provided on the dielectric layer and configured to overlap the plurality of lower electrodes and the plurality of dummy electrodes in a planar view, wherein the plurality of dummy electrodes have the same thickness as the plurality of lower electrodes, and the plurality of second conductive adhesive layers have the same thickness as the plurality of first conductive adhesive layers.

[0007] According to a second aspect of the present invention, there is provided the sensor device according to the first aspect, wherein an area of ​​the dielectric layer is larger than an overall outer area of ​​the plurality of second conductive adhesive layers 32.

[0008] According to a third aspect of the present invention, there is provided the sensor device according to the first aspect, wherein an area of ​​the dielectric layer is smaller than an overall outer area of ​​the plurality of second conductive adhesive layers 32.

[0009] According to a fourth aspect of the present invention, an area of ​​the upper electrode is larger than an area of ​​the dielectric layer, A sensor device according to a third aspect is provided, wherein the upper electrode is configured to be electrically connected to the plurality of second conductive adhesive layers 32.

[0010] According to a fifth aspect of the present invention, there is provided a sensor device according to the fourth aspect, wherein the upper electrode includes an electrode portion configured to be embedded between the plurality of dummy electrodes and between the plurality of second conductive adhesive layers.

[0011] According to a sixth aspect of the present invention, there is provided a sensor device according to the first aspect, wherein the dielectric layer is a piezoelectric layer.

[0012] According to a seventh aspect of the present invention, there is provided the sensor device according to the first aspect, wherein an area of ​​each of the plurality of dummy electrodes is the same as an area of ​​each of the plurality of lower electrodes.

[0013] According to an eighth aspect of the present invention, there is provided the sensor device according to the first aspect, wherein each of the plurality of lower electrodes has a quadrangle, and each of the plurality of dummy electrodes has a quadrangle.

[0014] According to a ninth aspect of the present invention, there is provided the sensor device according to the first aspect, wherein the upper electrode and the plurality of dummy electrodes are set to the same potential.

[0015] According to a tenth aspect of the present invention, there is provided the sensor device according to the first aspect, wherein the plurality of dummy electrodes are configured as a continuous layer so as to surround the plurality of lower electrodes. Effect of the Invention

[0016] According to the present invention, it is possible to provide a sensor device capable of preventing adjacent piezoelectric elements from shorting out. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a plan view of a sensor device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view illustrating a sensor region and a dummy region of the sensor device. [Diagram 3] FIG. 3 is a cross-sectional view of the sensor device taken along the line AA′ in FIG. [Figure 4] FIG. 4 is a schematic diagram illustrating a circuit connected to the piezoelectric element and the dummy element. [Diagram 5] FIG. 5 is a plan view of a sensor device according to the second embodiment of the present invention. [Figure 6]FIG. 6 is a cross-sectional view of the sensor device taken along the line AA′ in FIG. [Figure 7] FIG. 7 is a cross-sectional view of the sensor device taken along the line BB' in FIG. [Figure 8] FIG. 8 is a schematic diagram illustrating a circuit connected to the piezoelectric element and the dummy element. [Figure 9] FIG. 9 is a plan view of a sensor device according to the third embodiment of the present invention. [Figure 10] FIG. 10 is a plan view of a sensor device according to the fourth embodiment of the present invention. [Figure 11] FIG. 11 is a plan view of a sensor device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the embodiments will be described with reference to the drawings. However, the drawings are schematic or conceptual, and the dimensions and ratios of each drawing are not necessarily the same as those in reality. In addition, even when the same parts are shown between the drawings, the dimensional relationships and ratios of each may be different. In particular, the following embodiments are examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not specified by the shape, structure, arrangement, etc. of the components. In the following description, elements having the same function and configuration are given the same reference numerals, and duplicated descriptions are omitted.

[0019] [1] First embodiment [1-1] Configuration of sensor device 1 In this embodiment, a piezoelectric sensor will be described as an example of the sensor device. The piezoelectric sensor is a sensor device that utilizes the piezoelectric effect and is capable of outputting an electrical signal in response to pressure applied to a piezoelectric body.

[0020] Fig. 1 is a plan view of a sensor device 1 according to a first embodiment of the present invention. Fig. 2 is a plan view illustrating a sensor region 2 and a dummy region 3 of the sensor device 1. Fig. 3 is a cross-sectional view of the sensor device 1 taken along line AA' in Fig. 1. The X direction in Fig. 1 is a direction along one side of the sensor device 1, and the Y direction is a direction perpendicular to the X direction.

[0021] The sensor device 1 includes a base material 10. The base material 10 is made of an insulating material. The base material 10 is made of a glass substrate or an insulating film. Examples of the insulating film that can be used include polyimide, epoxy resin, PET (polyethylene terephthalate), and urethane.

[0022] The sensor device 1 has a sensor area 2 arranged in the center of the substrate 10 and a dummy area 3 arranged around the sensor area 2. The sensor area 2 has, for example, a rectangular shape. The dummy area 3 has, for example, a rectangular frame shape. The sensor area 2 is an area for detecting pressure. The dummy area 3 is not used for detecting pressure.

[0023] A plurality of piezoelectric elements 20 are provided as sensor elements in the sensor region 2 of the substrate 10. In FIG. 1, unhatched dashed squares indicate the piezoelectric elements 20. The piezoelectric elements 20 are elements that detect pressure. The piezoelectric elements 20 have, for example, a quadrilateral shape, typically a square shape. The plurality of piezoelectric elements 20 are arranged in a matrix. In FIG. 1, 15 (5×3) piezoelectric elements 20 are shown as an example.

[0024] A plurality of dummy elements 30 are provided in the dummy region 3 of the substrate 10. In FIG. 1, a hatched dashed square indicates the dummy element 30. The dummy element 30 is not used as a sensor, i.e., is not used to detect pressure. The dummy element 30 has, for example, a quadrangle, typically a square. The dummy element 30 has approximately the same area as the piezoelectric element 20. The dummy element 30 has the same laminated structure as the piezoelectric element 20. The plurality of dummy elements 30 are arranged so as to surround the entirety of the plurality of piezoelectric elements 20. The plurality of dummy elements 30 are arranged so as to be adjacent to the plurality of piezoelectric elements 20 in the X direction and the Y direction. The plurality of piezoelectric elements 20 and the plurality of dummy elements 30 are arranged in a matrix as a whole.

[0025] Next, a description will be given of the configuration of the piezoelectric element 20. Each of the piezoelectric elements 20 includes a plurality of lower electrodes 21 and a plurality of first conductive adhesive layers 22.

[0026] A plurality of lower electrodes 21 are provided on the substrate 10. The lower electrodes 21 have, for example, a quadrangular shape, typically a square shape. For example, molybdenum (Mo), aluminum (Al), or an alloy containing one of these is used as the lower electrodes 21.

[0027] A plurality of first conductive adhesive layers 22 are provided on the plurality of lower electrodes 21, respectively. The first conductive adhesive layer 22 has conductivity and functions to bond layers above and below itself. The first conductive adhesive layer 22 has approximately the same area as the lower electrode 21. The first conductive adhesive layer 22 is configured by dispersing conductive particles in a binder as an adhesive. A thermosetting resin, for example, an epoxy resin, is used as the binder. For example, silver (Ag) or gold (Au) is used as the conductive particles. More specifically, the first conductive adhesive layer 22 is configured of a silver paste. The first conductive adhesive layer 22 is hardened by applying heat.

[0028] A piezoelectric layer 11 is provided on the plurality of first conductive adhesive layers 22 as a dielectric layer. The piezoelectric layer 11 is a planar film provided in common to the plurality of piezoelectric elements 20. A portion of the piezoelectric layer 11 that overlaps with the first conductive adhesive layer 22 functions as a piezoelectric layer of one piezoelectric element 20. The piezoelectric layer 11 is made of a dielectric material, for example, an organic piezoelectric material. The piezoelectric layer 11 is made of a polymeric piezoelectric material, for example, polyvinylidene fluoride (PVDF), polyvinylidene fluoride / trifluoroethylene copolymer (P(VDF / TrFE)), or vinylidene cyanide / vinyl acetate copolymer (P(VDCN / VAc)). More preferably, the piezoelectric layer 11 is made of P(VDF / TrFE) that can be formed by a printing method. The piezoelectric layer 11 may be a single layer or a laminate of multiple layers.

[0029] An upper electrode 12 is provided on the piezoelectric layer 11. The upper electrode 12 is a planar electrode provided in common to the plurality of piezoelectric elements 20. The upper electrode 12 is made of a metal. For example, molybdenum (Mo), aluminum (Al), silver (Ag), gold (Au), or an alloy containing one of these metals is used as the upper electrode 12.

[0030] Next, a description will be given of the configuration of the dummy elements 30. Each of the multiple dummy elements 30 includes multiple dummy electrodes 31 and multiple second conductive adhesive layers 32.

[0031] A plurality of dummy electrodes 31 are provided on the substrate 10. The dummy electrodes 31 are not used as sensors. The planar shape and area of ​​the dummy electrodes 31 are the same as those of the lower electrode 21. The thickness of the dummy electrodes 31 is the same as that of the lower electrode 21. The material of the dummy electrodes 31 is the same as that of the lower electrode 21.

[0032] A plurality of second conductive adhesive layers 32 are provided on the plurality of dummy electrodes 31, respectively. The second conductive adhesive layers 32 have approximately the same area as the dummy electrodes 31. The thickness of the second conductive adhesive layers 32 is the same as that of the first conductive adhesive layer 22. The material of the second conductive adhesive layers 32 is the same as that of the first conductive adhesive layer 22.

[0033] A piezoelectric layer 11 is provided on the multiple second conductive adhesive layers 32. The piezoelectric layer 11 is provided in common to the multiple piezoelectric elements 20 and the multiple dummy elements 30. The area of ​​the piezoelectric layer 11 is set to be larger than the overall outer area of ​​the multiple second conductive adhesive layers 32. In other words, the piezoelectric layer 11 is configured to protrude from the multiple second conductive adhesive layers 32 to the outside of the dummy region 3. A portion of the piezoelectric layer 11 that overlaps with the second conductive adhesive layer 32 functions as a piezoelectric layer for one dummy element 30.

[0034] An upper electrode 12 is also provided on the piezoelectric layer 11 in the dummy region 3. The upper electrode 12 is provided in common to the plurality of piezoelectric elements 20 and the plurality of dummy elements 30. The area of ​​the upper electrode 12 is smaller than the area of ​​the piezoelectric layer 11 and is set to be approximately the same as the overall outer area of ​​the plurality of second conductive adhesive layers 32.

[0035] [1-2] Manufacturing method Next, a method for manufacturing the sensor device 1 will be described.

[0036] A glass substrate 10 is used as the base material 10. For example, a plurality of lower electrodes 21 and a plurality of dummy electrodes 31 are simultaneously formed on the glass substrate 10 by a sputtering method. The plurality of lower electrodes 21 and the plurality of dummy electrodes 31 are formed using the same material and with the same thickness. In this manufacturing process, a plurality of lead wirings connected to the plurality of lower electrodes 21 and the plurality of dummy electrodes 31, respectively, are also simultaneously formed.

[0037] Next, for example, by a screen printing method, a plurality of first conductive adhesive layers 22 and a plurality of second conductive adhesive layers 32 are simultaneously formed on the plurality of lower electrodes 21 and the plurality of dummy electrodes 31, respectively. The plurality of first conductive adhesive layers 22 and the plurality of second conductive adhesive layers 32 are formed using the same material and with the same thickness.

[0038] Next, a film-like piezoelectric layer 11 is bonded onto the plurality of first conductive adhesive layers 22 and the plurality of second conductive adhesive layers 32. The piezoelectric layer 11 is flexible. The piezoelectric layer 11 is configured to entirely cover the plurality of first conductive adhesive layers 22 and the plurality of second conductive adhesive layers 32. In this manufacturing process, the distance between the piezoelectric layer 11 and the glass substrate 10 is constant in the sensor region 2. Therefore, capillary action does not occur in the sensor region 2, and therefore it is possible to suppress the collapse of the pattern of the plurality of first conductive adhesive layers 22. The capillary action is a phenomenon in which a liquid is guided toward a narrower distance.

[0039] On the other hand, outside the dummy region 3, the peripheral end of the piezoelectric layer 11 sags, narrowing the gap between the piezoelectric layer 11 and the glass substrate 10. Therefore, in the dummy region 3, capillary action occurs, and the conductive adhesive layer is guided to the narrower gap (toward the outside of the dummy region 3). This may cause the pattern of the multiple second conductive adhesive layers 32 to collapse, causing adjacent dummy elements 30 to short out. However, even if adjacent dummy elements 30 short out, the configuration of the piezoelectric element 20 is not affected.

[0040] Next, the upper electrode 12 is formed on the piezoelectric layer 11 by, for example, a screen printing method. When using the screen printing method, a conductive ink is used as the upper electrode 12. The conductive ink is formed by dispersing conductive particles in a solvent. For example, silver (Ag) or gold (Au) is used as the conductive particles. After being applied, the conductive ink is dried and hardened. The upper electrode 12 may be formed by a sputtering method.

[0041] Thereafter, a protective layer (not shown) is formed to cover the entire sensor device 1. The protective layer is made of an insulating material, for example, a resin.

[0042] [1-3] Operation In the plurality of piezoelectric elements 20, the plurality of lower electrodes 21 are led out to the outside by a plurality of lead-out wirings (not shown), and a voltage can be applied to the plurality of lower electrodes 21 by using the plurality of lead-out wirings. The upper electrode 12 is led out to the outside by a plurality of lead-out wirings (not shown), and a voltage can be applied to the upper electrode 12 by using the lead-out wirings.

[0043] In the multiple dummy elements 30, multiple lead-out wirings for applying a voltage may be connected to the multiple dummy electrodes 31, or the lead-out wirings may not be connected. In this embodiment, as an example, a case where the lead-out wirings are connected to the multiple dummy electrodes 31 will be described. The multiple dummy electrodes 31 are led out to the outside by multiple lead-out wirings (not shown), and a voltage can be applied to the multiple dummy electrodes 31 using the multiple lead-out wirings.

[0044] 4 is a schematic diagram illustrating circuits connected to the piezoelectric element 20 and the dummy element 30. The sensor device 1 further includes a detection circuit 40 and a power supply circuit 41.

[0045] The detection circuit 40 is connected to the multiple lower electrodes 21 of the multiple piezoelectric elements 20 using multiple lead wires. The detection circuit 40 detects voltages output from the multiple piezoelectric elements 20. Specifically, the detection circuit 40 detects potential changes of the multiple lower electrodes 21.

[0046] The power supply circuit 41 generates a plurality of voltages. The power supply circuit 41 generates voltages necessary for the operation of the detection circuit 40 and supplies these voltages to the detection circuit 40. The power supply circuit 41 generates a ground voltage VSS (0V). The power supply circuit 41 is connected to the plurality of dummy electrodes 31 of the plurality of dummy elements 30 and the upper electrode 12 using a plurality of lead-out wirings. The power supply circuit 41 applies the ground voltage VSS to the plurality of dummy electrodes 31 and the upper electrode 12.

[0047] The piezoelectric element 20 is capable of outputting a voltage in response to an applied stress. The detection circuit 40 detects the output voltage of the piezoelectric element 20 based on the potential of the lower electrode 21 of the piezoelectric element 20.

[0048] [1-4] Effects of the first embodiment According to the first embodiment, the distance between the substrate 10 and the piezoelectric layer 11 can be made constant in the sensor region 2. This makes it possible to suppress the occurrence of capillary action in the sensor region 2, thereby suppressing the collapse of the pattern of the plurality of first conductive adhesive layers 22. This makes it possible to suppress the adjacent piezoelectric elements 20 from shorting out.

[0049] In addition, since the pattern of the plurality of first conductive adhesive layers 22 can be prevented from collapsing, the lower electrodes 21 can be miniaturized and the interval between adjacent lower electrodes 21 can be narrowed. This makes it possible to miniaturize the piezoelectric elements 20 and further miniaturize the piezoelectric element array. As a result, the resolution of the piezoelectric sensor can be improved.

[0050] Moreover, the electrodes of the dummy element 30 (including the dummy electrode 31) are set to the ground voltage VSS, whereby the noise of the piezoelectric element 20 disposed inside the dummy element 30 can be reduced.

[0051] [2] Second embodiment In the second embodiment, the upper electrode 12 is configured to be electrically connected to the dummy electrode 31 of the dummy element 30 and the second conductive adhesive layer 32 .

[0052] [2-1] Configuration of sensor device 1 Fig. 5 is a plan view of a sensor device 1 according to a second embodiment of the present invention. Fig. 6 is a cross-sectional view of the sensor device 1 taken along line AA' in Fig. 5. Fig. 7 is a cross-sectional view of the sensor device 1 taken along line BB' in Fig. 5. The positions of the sensor region 2 and the dummy region 3 are the same as in the first embodiment. The configuration of the multiple piezoelectric elements 20 arranged in the sensor region 2 is the same as in the first embodiment.

[0053] A piezoelectric layer 11 is provided on the plurality of first conductive adhesive layers 22 and the plurality of second conductive adhesive layers 32. The area of ​​the piezoelectric layer 11 is set to be smaller than the overall outer area of ​​the plurality of second conductive adhesive layers 32. The piezoelectric layer 11 is configured to partially overlap each of the plurality of second conductive adhesive layers 32. In a plan view, the portion of the upper surface of the second conductive adhesive layer 32 on the outer periphery side is not covered by the piezoelectric layer 11.

[0054] An upper electrode 12 is provided on the piezoelectric layer 11. The area of ​​the upper electrode 12 is set to be larger than the area of ​​the piezoelectric layer 11. The upper electrode 12 is configured to cover the peripheral side surfaces of the piezoelectric layer 11 and to be in contact with the plurality of second conductive adhesive layers 32. That is, as shown in Fig. 6, the upper electrode 12 includes an electrode portion 12A that is in contact with a portion of the upper surface of each of the plurality of second conductive adhesive layers 32 that is not covered by the piezoelectric layer 11.

[0055] Furthermore, the upper electrode 12 is configured to electrically connect adjacent second conductive adhesive layers 32 and electrically connect adjacent dummy electrodes 31. That is, as shown in Fig. 7, the upper electrode 12 includes an electrode portion 12B configured to be embedded between adjacent second conductive adhesive layers 32 and to be embedded between adjacent dummy electrodes 31.

[0056] The upper electrode 12 is formed using a conductive ink by, for example, screen printing. This makes it possible to form an electrode portion 12A that is in partial contact with the upper surface of each of the plurality of second conductive adhesive layers 32, and an electrode portion 12B that is embedded between adjacent second conductive adhesive layers 32 and between adjacent dummy electrodes 31.

[0057] The upper electrode 12 configured in this manner is electrically connected to the multiple dummy electrodes 31 and the multiple second conductive adhesive layers 32. In addition, the multiple dummy electrodes 31, the multiple second conductive adhesive layers 32, the electrode portion 12A, and the electrode portion 12B are configured to surround the sensor region 2 without any gaps.

[0058] [2-2] Operation 8 is a schematic diagram illustrating a circuit connected to the piezoelectric element 20 and the dummy element 30. The sensor device 1 further includes a detection circuit 40 and a power supply circuit 41. The configuration of the detection circuit 40 is the same as that of the first embodiment.

[0059] The power supply circuit 41 is connected to the upper electrode 12 using lead wiring. The power supply circuit 41 applies a ground voltage VSS (0V) to the upper electrode 12. The upper electrode 12 is electrically connected to the multiple dummy electrodes 31 and the multiple second conductive adhesive layers 32. Therefore, the upper electrode 12, the multiple dummy electrodes 31, and the multiple second conductive adhesive layers 32 are set to the ground voltage VSS. In other words, the multiple piezoelectric elements 20 are surrounded by electrodes to which the ground voltage VSS is applied.

[0060] A plurality of lead wires may be used to connect the power supply circuit 41 and the upper electrode 12. This makes it possible to stabilize the potential of the upper electrode 12.

[0061] [2-3] Effects of the second embodiment According to the second embodiment, the peripheral end of the piezoelectric layer 11 is bonded to the multiple second conductive adhesive layers 32, so that the peripheral end of the piezoelectric layer 11 can be fixed in a flat state. This can prevent the end of the piezoelectric layer 11 from sagging. Furthermore, it is possible to eliminate an area where the gap between the substrate 10 and the piezoelectric layer 11 is narrow. This can prevent the capillary phenomenon from occurring, so that the patterns of the multiple first conductive adhesive layers 22 and the multiple second conductive adhesive layers 32 can be prevented from collapsing. As a result, it is possible to prevent adjacent piezoelectric elements 20 from shorting out.

[0062] Furthermore, the electrodes included in the multiple dummy elements 30 can be used to surround the multiple piezoelectric elements 20. The electrodes surrounding the multiple piezoelectric elements 20 can be set to the ground voltage VSS. This makes it possible to reduce noise from the multiple piezoelectric elements 20.

[0063] Moreover, the electrodes included in the plurality of dummy elements 30 can be set to the ground voltage VSS simply by applying the ground voltage VSS to the upper electrode 12. Moreover, there is no need to connect lead-out wiring to the plurality of dummy elements 30. This makes it possible to simplify the circuit configuration.

[0064] [3] Third embodiment The third embodiment is an example relating to the patterns of the dummy electrodes 31 and the second conductive adhesive layer 32.

[0065] Fig. 9 is a plan view of a sensor device 1 according to a third embodiment of the present invention. The cross-sectional view of the sensor device 1 taken along line AA' shown in Fig. 9 is the same as Fig. 3. The positions of the sensor region 2 and the dummy region 3 are the same as those in the first embodiment.

[0066] 9, the multiple dummy electrodes 31 arranged along one side of the sensor device 1 are configured as a continuous layer. Also, the multiple second conductive adhesive layers 32 arranged along one side of the sensor device 1 are configured as a continuous layer.

[0067] Four dummy elements 30-1 are arranged at each of the four corners of the dummy region 3. Each of the four dummy elements 30-1 includes a dummy electrode 31-1 and a second conductive adhesive layer 32-1. The planar shape of the dummy electrode 31-1 is, for example, a square. The planar shape of the second conductive adhesive layer 32-1 is the same as that of the dummy electrode 31-1.

[0068] Two dummy elements 30-2 are arranged on each of two sides extending in the Y direction of the dummy region 3. Each of the two dummy elements 30-2 includes a dummy electrode 31-2 and a second conductive adhesive layer 32-2. The length of the dummy electrode 31-2 in the Y direction is approximately the same as the length of the sensor region 2 in the Y direction. The planar shape of the second conductive adhesive layer 32-2 is the same as that of the dummy electrode 31-2.

[0069] Two dummy elements 30-3 are arranged on each of two sides extending in the X direction of the dummy region 3. Each of the two dummy elements 30-3 includes a dummy electrode 31-3 and a second conductive adhesive layer 32-3. The length of the dummy electrode 31-3 in the X direction is approximately the same as the length of the sensor region 2 in the X direction. The planar shape of the second conductive adhesive layer 32-3 is the same as that of the dummy electrode 31-3.

[0070] A ground voltage VSS is applied to the four dummy electrodes 31-1, the two dummy electrodes 31-2, and the two dummy electrodes 31-3 by a power supply circuit 41 via a plurality of lead-out wirings.

[0071] According to the third embodiment, it is possible to easily form the patterns of the dummy electrode 31 and the second conductive adhesive layer 32. The other effects are the same as those of the first embodiment. It is also possible to apply the second embodiment to the third embodiment.

[0072] [4] Fourth embodiment The fourth embodiment is an example relating to the patterns of the dummy electrodes 31 and the second conductive adhesive layer 32.

[0073] Fig. 10 is a plan view of a sensor device 1 according to a fourth embodiment of the present invention. The cross-sectional view of the sensor device 1 taken along line AA' shown in Fig. 10 is the same as Fig. 3. The positions of the sensor region 2 and the dummy region 3 are the same as those in the first embodiment.

[0074] The dummy element 30 includes a dummy electrode 31 and a second conductive adhesive layer 32. The dummy electrode 31 is configured to surround the multiple piezoelectric elements 20 and has a rectangular frame shape. The second conductive adhesive layer 32 has the same planar shape as the dummy electrode 31. A ground voltage VSS is applied to the dummy electrode 31 by a power supply circuit 41 via a lead-out wiring.

[0075] Fig. 11 is a plan view of a sensor device 1 according to a modified example. The cross-sectional view of the sensor device 1 taken along line AA' shown in Fig. 11 is the same as Fig. 6. The positions of the sensor region 2 and the dummy region 3 are the same as those in the first embodiment.

[0076] The area of ​​the piezoelectric layer 11 is set to be smaller than the area of ​​the outline of the plurality of second conductive adhesive layers 32. The piezoelectric layer 11 is configured to partially overlap the second conductive adhesive layer 32. In a plan view, the outer peripheral portion of the upper surface of the second conductive adhesive layer 32 is not covered with the piezoelectric layer 11.

[0077] An upper electrode 12 is provided on the piezoelectric layer 11. The area of ​​the upper electrode 12 is set to be larger than the area of ​​the piezoelectric layer 11. The upper electrode 12 is configured to cover the peripheral side surfaces of the piezoelectric layer 11 and to be in contact with the second conductive adhesive layer 32. In other words, the upper electrode 12 includes an electrode portion 12A that is in contact with a portion of the upper surface of the second conductive adhesive layer 32 that is not covered by the piezoelectric layer 11.

[0078] The power supply circuit 41 applies a ground voltage VSS (0 V) to the upper electrode 12. The upper electrode 12, the dummy electrode 31, and the second conductive adhesive layer 32 are set to the ground voltage VSS.

[0079] According to the fourth embodiment, the patterning of the dummy electrode 31 and the second conductive adhesive layer 32 can be facilitated.

[0080] Moreover, the plurality of piezoelectric elements 20 can be surrounded by the dummy electrode 31 and the second conductive adhesive layer 32. The dummy electrode 31 and the second conductive adhesive layer 32 can be set to the ground voltage VSS. This makes it possible to reduce noise from the plurality of piezoelectric elements 20. Other effects are the same as those of the first embodiment.

[0081] In the above embodiments, a piezoelectric sensor has been described as an example of the sensor device 1, but the present invention is not limited thereto. This embodiment is applicable to various devices having a configuration in which an electrode and a dielectric layer are bonded with a conductive adhesive layer. This embodiment is applicable to a pyroelectric sensor, etc. A pyroelectric sensor includes a plurality of pyroelectric elements arranged in a matrix, and each pyroelectric element is configured by providing a pyroelectric layer between two electrodes.

[0082] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. In addition, the embodiments may be implemented in appropriate combination, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and the effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which the components are deleted can be extracted as an invention. [Explanation of symbols]

[0083] 1...sensor device, 2...sensor area, 3...dummy area, 10...substrate, 11...piezoelectric layer, 12...upper electrode, 20...piezoelectric element, 21...lower electrode, 22...first conductive adhesive layer, 30...dummy element, 31...dummy electrode, 32...second conductive adhesive layer, 40...detection circuit, 41...power supply circuit.

Claims

1. A substrate having a sensor region and a dummy region provided so as to surround the periphery of the sensor region; A plurality of lower electrodes provided in the sensor region of the substrate; a plurality of first conductive adhesive layers provided on the plurality of lower electrodes, respectively; a plurality of dummy electrodes provided in the dummy region of the base material, arranged so as to surround the plurality of lower electrodes, and not used as sensors; a plurality of second conductive adhesive layers provided on the plurality of dummy electrodes, respectively; a dielectric layer disposed on the plurality of first conductive adhesive layers and the plurality of second conductive adhesive layers; an upper electrode provided on the dielectric layer and configured to overlap the plurality of lower electrodes and the plurality of dummy electrodes in a plan view; Equipped with the plurality of dummy electrodes have the same thickness as the plurality of lower electrodes; The plurality of second conductive adhesive layers have the same thickness as the plurality of first conductive adhesive layers. Sensor device.

2. The area of ​​the dielectric layer is greater than the overall outer area of ​​the plurality of second conductive adhesive layers 32. The sensor device according to claim 1 .

3. The area of ​​the dielectric layer is smaller than the overall area of ​​the plurality of second conductive adhesive layers 32. The sensor device according to claim 1 .

4. the area of ​​the upper electrode is greater than the area of ​​the dielectric layer; The top electrode is configured to be electrically connected to the plurality of second conductive adhesive layers 32. The sensor device according to claim 3 .

5. The upper electrode includes an electrode portion configured to fill spaces between the plurality of dummy electrodes and between the plurality of second conductive adhesive layers. The sensor device according to claim 4.

6. The dielectric layer is a piezoelectric layer. The sensor device according to claim 1 .

7. The area of ​​each of the plurality of dummy electrodes is the same as the area of ​​each of the plurality of lower electrodes. The sensor device according to claim 1 .

8. Each of the plurality of bottom electrodes has a rectangular shape; Each of the plurality of dummy electrodes has a rectangular shape. The sensor device according to claim 1 .

9. The upper electrode and the plurality of dummy electrodes are set to the same potential. The sensor device according to claim 1 .

10. The plurality of dummy electrodes are formed in a continuous layer so as to surround the plurality of lower electrodes. The sensor device according to claim 1 .

Images