Pressure Sensor

Abstract

To provide a pressure sensor capable of stably detecting a pressing force without depending on a detection position of the pressing force.SOLUTION: A pressure sensor includes: a substrate; a plurality of first electrodes 20A, 20B, 20C and 20D provided on the substrate and arranged in first and second directions Dx and Dy; a second electrode facing the plurality of first electrodes 20; a third electrode 40A provided on the substrate and having a first lattice shape; an elastic body provided between the second electrode, the first electrodes 20A, 20B, 20C and 20D and the third electrode 40A and including conductive particles; and a plurality of wiring layers connected with the first electrode through contact holes provided in the substrate. Each of the plurality of wiring layers has a second lattice shape having a size different from that of the first lattice shape.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to pressure sensors. [Background technology]

[0002] 2. Description of the Related Art A pressure sensor is known that detects a pressing force by switching the electrical connection state of a switch depending on whether or not a pressing force is applied (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-080956 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to provide a pressure sensor with two-dimensional resolution on the surface where pressure is to be detected, multiple switches are arranged two-dimensionally. If the electrical characteristics of each switch are not uniform, it becomes technically difficult to ensure accurate detection of pressure at the position where the switch is located, where the electrical change in response to the presence or absence of pressure is relatively small.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a pressure sensor that can stably detect a pressing force regardless of the position where the pressing force is detected. [Means for solving the problem]

[0006] A pressure sensor according to one embodiment of the present disclosure comprises a substrate, a plurality of first electrodes provided on the substrate and arranged in a first direction and a second direction intersecting the first direction, a second electrode opposite the plurality of first electrodes, a third electrode provided on the substrate and having a first lattice shape, an elastic body including conductive particles provided between the second electrode and the first electrode and the third electrode, and a plurality of wiring layers connected to the first electrode via contact holes provided in the substrate, wherein each of the plurality of wiring layers has a second lattice shape different in size from the first lattice shape. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view of a laminated structure including the main components of a pressure sensor. [Figure 2] FIG. 2 is a diagram showing the pressure sensor receiving a pressing force from the second electrode side. [Figure 3] FIG. 3 is a diagram illustrating an example of a circuit configuration of a pressure sensor. [Figure 4] FIG. 4 is a plan view showing an example of the structure of the array. [Figure 5] FIG. 5 is a plan view showing an example of the positional relationship between a plurality of arrays. [Figure 6] FIG. 6 is a timing chart showing an example of electrical control when the pressure sensor configured with the circuit shown in FIG. 3 operates. [Figure 7] FIG. 7 is a cross-sectional view showing an example of the configuration of a pressure sensor according to a reference example. [Figure 8] FIG. 8 is a plan view illustrating the shape of the electrodes in the detection region of the pressure sensor according to the first modification. [Figure 9] FIG. 9 is a plan view showing an example of the configuration of the wiring layer in which the power supply lines Vbias and signal lines are provided within the array Un. [Figure 10] FIG. 10 is a plan view showing an example of the arrangement of contacts in an array Un that connect the electrode layer shown in FIG. 8 and the wiring layer shown in FIG. [Figure 11] FIG. 11 is a cross-sectional view of a laminated structure including the main components of a pressure sensor according to the second modification. DETAILED DESCRIPTION OF THE INVENTION

[0008] Each embodiment of the present disclosure will be described below with reference to the drawings. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the invention are naturally included within the scope of the present disclosure. Furthermore, to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0009] (Embodiment) FIG. 1 is a cross-sectional view of a laminated structure including the main components of a pressure sensor 1. The pressure sensor 1 is a so-called device substrate in which multiple components are laminated on a substrate 10. The multiple components include a field effect transistor (FET) using a semiconductor. Specifically, on the substrate 10, an insulating film 11, a first wiring layer 12, a first insulating layer 13, a semiconductor layer 14, a second wiring layer 15, a second insulating layer 16, a third wiring layer 17, a third insulating layer 18, a fourth wiring layer 19, etc. are laminated in this order from the side closest to the substrate 10. The first wiring layer 12, the second wiring layer 15, the third wiring layer 17, and the fourth wiring layer 19 are formed using a conductive material such as a metal electrode. The first insulating layer 13, the second insulating layer 16, and the third insulating layer 18 are formed using an insulator containing, for example, silicon oxide or silicon nitride. The semiconductor layer 14 is a semiconductor that functions as a channel of the FET. When the FET is a MOSFET (Metal Oxide Semiconductor FET), the semiconductor layer 14 is made of, for example, silicon (Si). By using this stacked structure, FETs such as a first element 61 shown in FIG. 1 and a second element 62, a third element 63, and a fourth element 64 shown in FIG. 3 (described later) are formed on the substrate 10.

[0010] In the following description, one direction along the substrate 10 is referred to as a first direction Dx. Another direction along the substrate 10 and perpendicular to the first direction Dx is referred to as a second direction Dy. A direction perpendicular to the first direction Dx and the second direction Dy is referred to as a third direction Dz. The third direction Dz is the stacking direction of the stacked structure formed on the substrate 10.

[0011] A coating portion HRC, an electrode layer, and the like are further laminated on the upper side of the fourth wiring layer 19. The coating portion HRC is laminated between the fourth wiring layer 19 and the electrode layer to insulate the fourth wiring layer 19 from the electrode layer. The coating portion HRC is an organic layer that protects the components below the coating portion HRC by preventing a pressing force from the second electrode 30 (described later) from being applied to the components below the coating portion HRC. The electrode layer includes a first electrode 20 and a third electrode 40. The first electrode 20 and the third electrode 40 are spaced apart. An elastic body 50 is further provided on the upper side of the electrode layer. The elastic body 50 is a thin-film elastic member. The elastic body 50 includes a plurality of conductive particles 51. The elastic body 50 including the conductive particles 51 exhibits pressure-sensitive conductivity.

[0012] Furthermore, a second electrode 30 is provided on the upper side of the elastic body 50. The second electrode 30 is a conductive sheet, and the second electrode 30 may be a sheet-like member that exhibits conductivity at least on the elastic body 50 side. More specifically, the second electrode 30 has a compound thin film such as ITO (Indium Tin Oxide) provided on the elastic body 50 side. The side of the second electrode 30 opposite the elastic body 50 may be conductive, or may be coated with an insulator such as synthetic resin.

[0013] FIG. 2 is a diagram illustrating the pressure sensor 1 receiving a pressing force from the second electrode 30 side. When the pressure sensor 1 shown in FIG. 1 receives a pressing force in the third direction Dz from the second electrode 30 side, the elastic body 50 is compressed in the third direction Dz as shown in FIG. 2. As a result, some of the multiple conductive particles 51 contained in the elastic body 50 form conductive paths that electrically connect the third electrode 40 and the second electrode 30 and the first electrode 20 and the second electrode 30. FIG. 2 schematically illustrates a state in which the conductive particle 51a connects the third electrode 40 and the second electrode 30, and the conductive particle 51b connects the first electrode 20 and the second electrode 30. The conductive particle 51a and the conductive particle 51b are part of the multiple conductive particles 51. When the pressing force in the third direction Dz from the second electrode 30 side is removed, the state shown in FIG. 2 returns to the state shown in FIG. 1, and the conductive paths are lost. In this way, the pressure sensor 1 can detect the pressing force from the second electrode 30 side based on whether or not the conduction path is established. Furthermore, the third electrode 40, second electrode 30, first electrode 20, and elastic body 50 that form the conduction path in response to the pressing force from the second electrode 30 side function as a switch 80 that switches between open and closed in response to the pressing force. Note that the second electrode 30 of the embodiment is in a floating state when it is not receiving the pressing force and is not connected to the first electrode 20 and the third electrode 40.

[0014] More specifically, the elastic body 50 exhibits anisotropic pressure-sensitive conductivity that establishes electrical continuity between the third electrode 40 and the second electrode 30 and between the first electrode 20 and the second electrode 30 in response to a pressing force in a direction along the third direction Dz, but does not establish electrical continuity in other directions (such as the direction along the substrate 10). The conductive particles 51 are provided in the elastic body 50 so as to establish such pressure-sensitive conductivity.

[0015] In the embodiment, the sheet resistance of the third electrode 40 is smaller than the sheet resistance of the second electrode 30. Specifically, the electrode layers constituting the first electrode 20 and the third electrode 40 are made of a metal with extremely high conductivity, such as silver (Ag). Although the specific composition of the third electrode 40 is not limited thereto, it is desirable that the third electrode 40 be made of a material with as high conductivity and as low sheet resistance as possible.

[0016] Fig. 3 is a diagram showing an example of the circuit configuration of the pressure sensor 1. The circuit shown in Fig. 3 includes an array configuration section SC and a reset section RC.

[0017] The array component SC includes a first element 61, a second element 62, a third element 63, and the like. The first element 61, the second element 62, and the third element 63 are switching elements configured with FETs. The first element 61 has one of its source and drain connected to the switch 80, and the other connected to the second element 62, the third element 63, and the capacitor 70. The second element 62 has one of its source and drain connected to a signal line Sig, and the other connected to the first element 61, the third element 63, and the capacitor 70. The third element 63 has one of its source and drain connected to an initialization potential line Vbl, and the other connected to the first element 61, the second element 62, and the capacitor 70. The first element 61 has a gate and a back gate connected to a detection operation signal transmission line Vs. The second element 62 has a gate and a back gate connected to a scanning line Gate. The third element 63 has a gate and a back gate connected to an initialization signal transmission line Vdch.

[0018] The capacitor 70 has two terminals, one of which is connected to the common potential line Vcom, and the other of which is connected to the first element 61, the second element 62, and the third element 63. The switch 80 is provided so as to be able to open and close one of the source or drain of the first element 61 and the power supply line Vbias.

[0019] The reset unit RC includes a fourth element 64. The fourth element 64 is a switching element configured with an FET. One of the source or drain of the fourth element 64 is connected to the signal line Sig, and the other is connected to the reset potential line VR1. The gate and back gate of the fourth element 64 are connected to the reset signal transmission line Vrst.

[0020] An array configuration section SC is provided for each array that can detect pressure individually. The pressure sensor 1 is provided with multiple arrays, as exemplified in FIG. 5 described later. The scanning line Gate is shared by multiple arrays aligned in the first direction Dx. The signal line Sig is shared by multiple arrays aligned in the second direction Dy. The detection operation signal transmission line Vs, the power supply line Vbias, the common potential line Vcom, the initialization potential line Vbl, and the initialization signal transmission line Vdch are shared by all arrays.

[0021] FIG. 4 is a plan view showing an example of the structure of an array. The term "plan view" refers to a front view of a plane in the first direction Dx-second direction Dy along the surface of the substrate 10. As shown in FIG. 4, one array includes a first element 61, a second element 62, and a third element 63. Furthermore, a scanning line Gate, a signal line Sig, a detection operation signal transmission line Vs, a common potential line Vcom, an initialization potential line Vbl, and an initialization signal transmission line Vdch are provided to establish the circuit described with reference to FIG. 3. The array structure shown in FIG. 4 is established by the layered structure on the substrate 10 described with reference to FIG. 1. The first electrode 20 and the third electrode 40 shown in FIG. 4 are provided on the same layer (electrode layer) as shown in FIG. 1. The first element 61, the second element 62, the third element 63, the scanning line Gate, the signal line Sig, the detection operation signal transmission line Vs, the common potential line Vcom, the initialization potential line Vbl, and the initialization signal transmission line Vdch are provided closer to the substrate 10 than the electrode layer.

[0022] As shown in FIG. 4, the position of the first element 61 in a plan view partially overlaps the position of the first electrode 20 in a plan view. As shown in FIG. 1, the second wiring layer 15 stacked on the semiconductor layer 14 of the FET constituting the first element 61 includes an electrode 15a connected to the semiconductor layer 14 and formed as one of the source and drain of the first element 61. The electrode 15a is connected to a connection portion 19a through a contact hole formed in the second insulating layer 16 and the third insulating layer 18. The connection portion 19a is formed when the fourth wiring layer 19 is stacked. The connection portion 19a connects the first electrode 20 and the electrode 15a. The connection portion 19a and the first electrode 20 are connected through a contact hole formed above the connection portion 19a in the covering portion HRC. In FIG. 1 and other figures, the first electrode 20 has a cross-sectional shape curved along the contact hole. However, this is merely an example of the shape of the first electrode 20 and is not limited thereto and can be modified as appropriate.

[0023] As shown in FIGS. 1 and 4, the first electrode 20 is formed so as to be spaced apart from the third electrode 40. FIG. 4 illustrates a square first electrode 20 in which two opposing sides of the four sides are aligned along the first direction Dx and the other two opposing sides are aligned along the second direction Dy. The shape of the first electrode 20 is not limited to this. The shape of the first electrode 20 may be changed as appropriate as long as it allows for an appropriate separation from the third electrode 40. As shown in FIG. 4, for example, one first electrode 20 is provided in one array.

[0024] FIG. 5 is a plan view showing an example of the positional relationship of multiple arrays. The first electrodes 20 described with reference to FIG. 4 are provided in multiple numbers, for example, as shown in FIG. 5. The multiple first electrodes 20 shown in FIG. 5 are arranged in a matrix along the first direction Dx and the second direction Dy. In FIG. 5, 3 × 3 first electrodes 20 are arranged in the first direction Dx and the second direction Dy, but an actual pressure sensor 1 includes many more first electrodes 20. To give a specific example, 80 × 84 first electrodes 20 are arranged. Furthermore, the pitch between adjacent first electrodes 20 in the first direction Dx (or the second direction Dy) is 321 μm. This specific example is merely an example and is not limited to this and can be modified as appropriate.

[0025] The arrays described with reference to FIGS. 3 and 4 are provided in plurality to correspond to the arrangement of the plurality of first electrodes 20 described with reference to FIG. 5. The plurality of arrays provided to correspond to the plurality of first electrodes 20 arranged along the first direction Dx share a scanning line Gate. As shown in FIG. 4, the scanning line Gate is provided to extend along the first direction Dx. The plurality of arrays provided to correspond to the plurality of first electrodes 20 arranged along the second direction Dy share a signal line Sig. As shown in FIG. 4, the signal line Sig is provided to extend along the second direction Dy. With the configuration of the first electrodes 20 and arrays provided in this manner, from a planar view, one signal line Sig runs along the second direction Dy between adjacent first electrodes 20 among the plurality of first electrodes 20 arranged in the first direction Dx. Furthermore, from a planar view, one scanning line Gate runs along the first direction Dx between adjacent first electrodes 20 among the plurality of first electrodes 20 arranged in the second direction Dy. That is, in plan view, the plurality of first electrodes 20 are partitioned into a grid by the signal lines Sig and the scanning lines Gate.

[0026] As shown in FIG. 5 , the third electrode 40 is formed as a continuous electrode that divides the first electrode 20 into a grid pattern. The third electrode 40 shown in FIG. 5 divides the first electrodes 20 arranged in the first direction Dx and the first electrodes 20 arranged in the second direction Dy. In other words, the third electrode 40 has openings 25 that accommodate the first electrodes 20 inside. That is, the third electrode 40 is an electrode in which the openings 25 are arranged in a matrix. The openings 25 separate the first electrodes 20 from the third electrode 40. Specifically, as shown in FIG. 4 , one side of the first electrode 20 is separated from one side of the opening of the third electrode 40 facing the first electrode 20 by a distance Wi. The shape of the openings 25 is not limited to a square and can be changed as appropriate. The distance Wi is, for example, 50 μm, but is not limited to this and can be changed as appropriate. The interval Wi is preferably equal to or greater than the thickness of the elastic body 50 in the third direction Dz, and less than 25% (for example, about 22.5%) of the smaller of the width in the first direction Dx or the width in the second direction Dy of each region partitioned in a grid pattern by the signal lines Sig and the scanning lines Gate. Although not shown in Fig. 4, the interval between the third electrode 40 and the side of the first electrode 20 opposite to the side on which the interval Wi is written is also the interval Wi.

[0027] The third electrode 40 is connected to a power supply line Vbias provided outside the detection area SA where the plurality of first electrodes 20 are provided. Note that the detection area SA is an area where the plurality of first electrodes 20 are provided and where pressing force from the second electrode 30 side can be detected, as shown in FIG.

[0028] As shown in FIG. 5, a peripheral area FA is provided to surround the outside of the detection area SA. The power supply line Vbias is provided so as to trace the peripheral area FA. The power supply line Vbias and the third electrode 40 are connected in the third direction Dz via a contact 45. Specifically, the third electrode 40 has an extension portion 40a extending from the detection area SA to the peripheral area FA. The extension portion 40a overlaps with the power supply line Vbias and the contact 45 in a plan view. The extension portion 40a is connected to the power supply line Vbias via the contact 45. As a result, the potential of the third electrode 40 becomes the potential of the power supply line Vbias (for example, a constant potential C4 described later). In this way, the power supply line Vbias functions as a power supply unit. The power supply line Vbias is formed on the substrate 10 in the same layer as any of the wiring layers (e.g., the first wiring layer 12, the second wiring layer 15, the third wiring layer 17, and the fourth wiring layer 19) below the coating portion HRC, but is not limited to this. For example, a wiring layer dedicated to the power supply line Vbias may be stacked on the substrate 10. The contact 45 is a contact formed in a contact hole that penetrates the coating portion HRC and the insulating layer located above the wiring layer in the third direction Dz so as to connect the wiring layer on which the power supply line Vbias is formed to the third electrode 40.

[0029] 5 illustrates a peripheral area FA near one corner of the outer edge of the detection area SA, but the peripheral area FA is provided to surround the detection area SA in a plan view. The power supply line Vbias is provided to overlap the peripheral area FA in a plan view and surround the detection area SA. The multiple contacts 45 are provided to overlap the peripheral area FA in a plan view, surround the detection area SA, and trace the power supply line Vbias. Note that while FIG. 5 illustrates a single row of contacts 45 that traces the power supply line Vbias, multiple rows of contacts 45 may be provided to trace the power supply line Vbias.

[0030] 4 and 5, the reset unit RC shown in Fig. 3 is shared by a plurality of arrays that share the signal line Sig. The reset potential line VR1 is shared by all the reset units RC.

[0031] FIG. 6 is a timing chart showing an example of electrical control when the pressure sensor 1 configured with the circuit shown in FIG. 3 is operating. In periods other than the period T1 specifically shown in FIG. 6, the third element 63 is in a state in which signal transmission between the source and drain is blocked (OFF). In periods other than the period T2 specifically shown in FIG. 6, the first element 61 is in a state in which signal transmission between the source and drain is blocked (OFF). In periods other than the period T3 specifically shown in FIG. 6, the second element 62 is in a state in which signal transmission between the source and drain is blocked (OFF). In periods other than the period T3 specifically shown in FIG. 6, the fourth element 64 is in a state in which signal transmission between the source and drain is possible (ON). In other words, in periods other than the periods T1, T2, and T3, the initialization signal transmission line Vdch, the detection operation signal transmission line Vs, the reset signal transmission line Vrst, and the scanning line Gate are set to potentials that realize the states of the first element 61, the second element 62, the third element 63, and the fourth element 64. The potentials of the initialization potential line Vbl, the reset potential line VR1, the common potential line Vcom, and the power supply line Vbias are constant potentials that are individually determined in advance. The constant potential C1 of the initialization potential line Vbl, the constant potential C2 of the reset potential line VR1, the constant potential C3 of the common potential line Vcom, and the constant potential C4 of the power supply line Vbias shown in Fig. 5 may all be different potentials, or some of them may be equal. In this embodiment, the constant potential C3 and the constant potential C4 are equal.

[0032] Furthermore, a plurality of scanning lines Gate are provided according to the number of arrays aligned in the first direction Dx. In FIG. 6, the scanning lines Gate are indicated by symbols Gate(1), ..., Gate(n). The scanning lines Gate are sequentially supplied with drive signals from a scanning circuit (not shown). The scanning circuit includes, for example, a shift register. The number of shift outputs of the shift register is the same as the number (n) of scanning lines Gate. n is a natural number equal to or greater than 2. The scanning lines Gate to which the drive signals output by the scanning circuit are supplied by the shift register are sequentially shifted from Gate(1), ..., Gate(n).

[0033] First, during period T1, the potential of the initialization signal transmission line Vdch becomes high (H). This connects the circuit between the source and drain of the third element 63. Therefore, the other of the two terminals of the capacitor 70 connected to the other of the source or drain of the third element 63 is electrically connected to the initialization potential line Vbl. By being electrically connected to the initialization potential line Vbl, the capacitor 70 releases the capacitance it held before connection. In other words, the capacitance held by the capacitor 70 becomes a state corresponding to the potential difference between the common potential line Vcom and the initialization potential line Vbl. This state is when the capacitor 70 is reset. As described above, the initialization signal transmission line Vdch is shared by all arrays, and therefore the capacitors 70 of all arrays are reset during period T1.

[0034] Next, during period T2, the potential of the detection operation signal transmission line Vs becomes high (H). This connects the circuit between the source and drain of the first element 61. Therefore, whether the power supply line Vbias is connected to one of the terminals of the capacitor 70 changes depending on whether the switch 80 connected to one of the source and drain of the first element 61 is turned on or off. Specifically, when the pressure sensor 1 is receiving a pressing force from the second electrode 30 side, the power supply line Vbias is connected to one of the terminals of the capacitor 70. On the other hand, when the pressure sensor 1 is not receiving a pressing force from the second electrode 30 side, the power supply line Vbias is not connected to one of the terminals of the capacitor 70. In this way, the capacitance stored in the capacitor 70 changes depending on whether the pressure sensor 1 is receiving a pressing force from the second electrode 30 side during period T2.

[0035] Then, during period T3, the potential of the reset signal transmission line Vrst is low (L). Note that during periods excluding period T3 and portions before and after period T3, the fourth element 64 is ON, and therefore the signal line Sig and the reset potential line VR1 are connected. During the period in which the fourth element 64 is ON, the potential of the signal line Sig is reset by the potential of the reset potential line VR1. The low (L) / high (H) state of the signal transmission line Vrst is reversed before and after period T3, and as a result, the potential of the reset signal transmission line Vrst during period T3 is low (L), and therefore the connection between the signal line Sig and the reset potential line VR1 is cut off.

[0036] During the period T3, the potentials of the scanning lines Gate(1), ..., Gate(n) are controlled so as to sequentially reverse between high (H) and low (L). FIG. 6 illustrates an example in which one of the scanning lines Gate(1), ..., Gate(n) becomes high (H) in response to the application of the drive signal. This sequentially turns on the second elements 62 of the arrays that share the scanning line Gate but do not share the signal line Sig, i.e., the arrays aligned in the first direction Dx, and connects the capacitor 70 to the signal line Sig. Therefore, the potential of the signal line Sig corresponds to the capacitance held in the capacitor 70. This allows pressure to be detected by the pressure sensor 1 connected to the signal line Sig. The pressure sensor 1 is a circuit that determines whether the pressure sensor 1 is receiving a pressing force from the second electrode 30 side based on the potential of the signal line Sig.

[0037] Although not shown, the pressure sensor 1 includes various circuits for performing the electrical control described with reference to Fig. 6. Specifically, the pressure sensor 1 is provided with a power supply circuit that supplies potentials corresponding to high (H) / low (L) of the initialization signal transmission line Vdch, the initialization potential line Vbl, the detection operation signal transmission line Vs, the reset signal transmission line Vrst, etc., and potentials corresponding to constant potentials C1, C2, C3, and C4, and a control circuit that controls switching between high (H) and low (L) corresponding to the periods T1, T2, and T3 described with reference to Fig. 6.

[0038] The above explanation has been based on the circuit configuration of Fig. 3, but the circuit configuration of the pressure sensor 1 is not limited to that shown in Fig. 3. In principle, the pressure sensor according to the present disclosure operates as long as there are the first element 61, the second element 62, the capacitor 70, and the switch 80, as well as the source-drain connections and the supply of potentials to the gates thereof. The third element 63 and the fourth element 64 are specific configuration examples for resetting the potential, and are not essential for pressure detection.

[0039] As described with reference to FIGS. 1, 2, 4, and 5, the pressure sensor 1 of this embodiment has the first electrode 20 and the third electrode 40 spaced apart by the opening 25. In other words, the first electrode 20 and the third electrode 40 are disposed so as to be adjacent to each other in a non-contact positional relationship across the interval Wi (see FIG. 4). As a result, regardless of where a pressing force from the second electrode 30 is detected in the detection area SA including the plurality of first electrodes 20 arranged along the surface of the substrate 10, the electrical separation distance between the first electrode 20 and the third electrode 40 that are brought into conduction in response to the pressing force is substantially the same. This is because, since the intervals between the first electrode 20 and the third electrode 40 are uniform at the interval Wi, the length of the conduction path through the second electrode 30 when the first electrode 20 and the third electrode 40 are electrically connected to each other via the conductive particles 51 and the second electrode 30 is substantially the same as the interval Wi. Additionally, in the embodiment, the power supply line Vbias is supplied via the third electrode 40, which has a lower sheet resistance than the second electrode 30, so there is almost no attenuation of the current from the power supply line Vbias until it reaches the conduction path of the second electrode 30. Therefore, no matter where in the detection area SA a pressing force is applied from the second electrode 30 side, a state is established in which it is clear to distinguish between the electrical state when a conduction path between the first electrode 20 and the third electrode 40 is established and the electrical state when the conduction path is not established. In this way, according to the embodiment, the pressing force can be stably detected regardless of the position where the pressing force is detected.

[0040] FIG. 7 is a cross-sectional view showing an example of the configuration of a pressure sensor according to a reference example. Unlike the embodiment, the pressure sensor shown in FIG. 7 does not include a third electrode 40. Therefore, a power supply showing the same potential as the power supply line Vbias is connected to the second electrode 30. Furthermore, since there is no configuration for connecting the power supply and the second electrode 30 within the detection area SA, the second electrode 30 is inevitably connected to the power supply outside the detection area SA. Note that the elastic body 50 shown in FIG. 7 is in a state where it is receiving a pressing force from the second electrode 30 side.

[0041] Because the second electrode 30 has a higher sheet resistance than the third electrode 40 in the embodiment, the farther the pressure detection position is from the power supply in the reference example, the greater the attenuation of the current from the power supply due to the sheet resistance of the second electrode 30. Therefore, the farther the pressure detection position is from the power supply, the less clear the distinction becomes between the electrical state when a conduction path is established between the second electrode 30 and the third electrode 40, as shown in FIG. 7 , and the electrical state when the conduction path is not established. This is because the greater attenuation of the current from the power supply due to the sheet resistance of the second electrode 30 indicates that even if the conduction path is established, the electrical change caused by the influence of the current is smaller. Thus, compared to the reference example, the embodiment can suppress variations in detection accuracy depending on the positional relationship between the pressure detection position within the detection area SA and the power supply. Therefore, the embodiment can stably detect the pressure, regardless of the pressure detection position, as described above.

[0042] As described above, the pressure sensor 1 of the embodiment includes a plurality of first electrodes 20 arranged along the substrate 10, an elastic body 50 in contact with the plurality of first electrodes 20, a second electrode 30 in contact with the elastic body 50 and sandwiching the elastic body 50 between the elastic body 50 and the first electrode 20, and a third electrode 40 disposed closer to the substrate 10 than the second electrode 30 and electrically connected to the second electrode 30. The elastic body 50 contains conductive particles that electrically connect the first electrode 20 and the second electrode 30 when a pressing force is applied to bring the first electrode 20 and the second electrode 30 closer together. The third electrode 40 is continuous in a lattice pattern that separates adjacent first electrodes 20 in at least one direction. In other words, the third electrode 40, which has the same potential as the second electrode 30 that connects to the first electrode 20 when a pressing force is applied, is arranged near the first electrode 20 so as to separate adjacent first electrodes 20. Therefore, the first electrode 20 and the third electrode 40, which are electrically connected when pressed, can be positioned closer to each other. This makes it easier to stabilize the electrical characteristics of a switch (e.g., switch 80) including the first electrode 20 and the third electrode 40, regardless of the arrangement of the switch. Therefore, the pressure sensor 1 can stably detect a pressing force regardless of the position where the pressing force is detected.

[0043] The pressure sensor 1 also includes a detection area SA in which multiple first electrodes 20 are arranged in a matrix, and transistors (second elements 62). The detection area SA includes multiple signal lines Sig extending along either the row direction (first direction Dx) or the column direction (second direction Dy), and multiple scanning lines Gate extending along the other of the row and column directions. Each transistor has one of its source and drain connected to the substrate 10 via the first elements 61, the other of its source and drain connected to the signal line Sig, and its gate connected to the scanning line Gate. This allows the transistor to operate on a scanning line Gate-by-scan line basis, and a signal indicating the electrical state of the first electrode 20 connected to the operated transistor via the first element 61 is obtained via the signal line Sig. In other words, the electrical state of the first electrode 20 can be scanned by scanning the scanning line Gate. Therefore, a pressed portion within the detection area SA where the first electrode 20 and the second electrode 30 are electrically connected can be detected.

[0044] Furthermore, the third electrode 40 and the plurality of first electrodes 20 are formed in the same layer, which allows the first electrode 20 and the third electrode 40 to be formed in the same process, thereby enabling the pressure sensor 1 to be manufactured at lower cost.

[0045] Furthermore, the third electrode 40 continues along the substrate 10 so as to surround all four sides of each first electrode 20. This makes it possible to more qualitatively determine the positional relationship between the first electrode 20 and the third electrode 40, which has the same potential as the second electrode 30 that is connected to the first electrode 20 when a pressing force is applied, and the electrical characteristics of a switch (e.g., switch 80) including the first electrode 20 and the third electrode 40 can be more stabilized regardless of the arrangement of the switch.

[0046] Furthermore, the sheet resistance of the third electrode 40 is smaller than the sheet resistance of the second electrode 30. As a result, a conduction path is established that includes the first electrode 20 and the third electrode 40 that is closest to the first electrode 20, the second electrode 30, and the third electrode 40 that are connected when pressed, and the electrical characteristics of a switch (for example, switch 80) that includes the first electrode 20 and the third electrode 40 can be more easily stabilized regardless of the arrangement of the switch.

[0047] The third electrode 40 also has an extending portion 40a that extends outside (the peripheral area FA) of the area (the detection area SA) where the plurality of first electrodes 20 are provided and is connected to the power supply line Vbias. The first electrode 20 and the third electrode 40 are electrically connected when a pressing force is applied that brings the first electrode 20 and the second electrode 30 closer to each other. This allows the configuration for connecting the first electrode 20 and the third electrode 40 to be the same as the configuration for connecting the first electrode 20 and the second electrode 30. Therefore, the pressure sensor 1 can be manufactured at lower cost.

[0048] Furthermore, the second electrode 30 is electrically floating when not electrically connected to the third electrode 40. In other words, there is no need for a configuration for constantly applying a specific potential from the outside to the second electrode 30. This allows the pressure sensor 1 to be manufactured at lower cost.

[0049] (Variation) Modified examples in which the specific configuration of some components differs from that of the embodiment will be described below with reference to Figures 8 to 11. In the description of the modified examples, components similar to those of the embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0050] (Variation 1) FIG. 8 is a plan view illustrating the shape of electrodes in the detection area SA of a pressure sensor according to Modification 1. As shown in FIG. 8, in Modification 1, array electrode 20A, array electrode 20B, array electrode 20C, array electrode 20D, and third electrode 40A are provided in array Un. Although reference numerals are omitted, FIG. 8 illustrates a configuration in which a 3×3 array Un is arranged, with three arrays Un arranged in the first direction Dx and three in the second direction Dy. More or fewer arrays Un may be arranged in the detection area SA. In this way, the pressure sensor of Modification 1 has multiple arrays Un arranged in a matrix within the detection area SA when viewed from a plan view.

[0051] The array electrodes 20A, 20B, 20C, and 20D are functionally similar in configuration to the first electrode 20 in the embodiment. Furthermore, the third electrode 40A is functionally similar in configuration to the third electrode 40 in the embodiment. In Modification 1, the first electrodes 20 in each array are replaced with a plurality of first electrodes such as the array electrodes 20A, 20B, 20C, and 20D. Furthermore, in Modification 1, the shape in a plan view is changed from the third electrode 40 in the embodiment, such as the third electrode 40A, depending on the number, shape, and arrangement of the plurality of first electrodes.

[0052] In the example shown in FIG. 8, array electrodes 20A and 20B, which are aligned in the first direction Dx within the array Un, are adjacent to each other without a third electrode 40A sandwiched between them. Also, array electrodes 20C and 20D, which are aligned in the first direction Dx within the array Un, are adjacent to each other without a third electrode 40A sandwiched between them. Meanwhile, array electrodes 20A and 20C, which are aligned in the second direction Dy within the array Un, are adjacent to each other with a third electrode 40A sandwiched between them. Also, array electrodes 20B and 20D, which are aligned in the second direction Dy within the array Un, are adjacent to each other with a third electrode 40A sandwiched between them. Thus, the third electrode 40A is continuous in a lattice pattern, separating adjacent first electrodes in at least one direction (e.g., the second direction Dy) among the plurality of adjacent first electrodes within the array Un. The positional relationship between the plurality of first electrodes and the third electrode 40A within the array Un is not limited to this. For example, the first direction Dx and the second direction Dy in Fig. 8 may be interchanged. Furthermore, the third electrode 40A may extend so as to further separate the array electrodes 20A and 20B, and the array electrodes 20C and 20D, within the array Un.

[0053] In Modification 1, a plurality of first electrodes provided in one array Un, such as array electrodes 20A, 20B, 20C, and 20D, share one second element 62. Note that Modification 1 may also be configured such that the first element 61 shown in FIG. 3 is omitted, and a switch 80 is connected to the second element 62, the third element 63, and the capacitor 70. In Modification 1, opening and closing (ON / OFF) of the switch 80 refers to switching between conduction (ON) and non-conduction (OFF) between the third electrode 40, the second electrode 30, and the array electrodes 20A, 20B, 20C, and 20D.

[0054] FIG. 9 is a plan view showing an example of the configuration of the wiring layer in the array Un in which the power supply lines Vbias and the signal lines Sig are provided.

[0055] Fig. 10 is a plan view showing an example of the arrangement in the array Un of contacts that connect the electrode layer shown in Fig. 8 and the wiring layer shown in Fig. 9. The contacts shown in Fig. 10 are formed so as to penetrate the coating portion HRC.

[0056] As shown in Fig. 9, the connection portion 19a of Modification 1 extends to correspond to the shape and arrangement of the array electrodes 20A, 20B, 20C, and 20D in a plan view. The extending connection portion 19a is connected to the array electrodes 20A, 20B, 20C, and 20D via one or more contacts included in the contact formation regions 20P, 20Q, 20R, and 20S shown in Fig. 10. Specifically, the array electrode 20A is connected to the connection portion 19a shown in Fig. 9 via a contact 451 included in the contact formation region 20P shown in Fig. 10. The array electrode 20B is connected to the connection portion 19a shown in Fig. 9 via a contact 452 included in the contact formation region 20Q shown in Fig. 10. The array electrode 20C is connected to the connection portion 19a shown in Fig. 9 via a contact 453 included in the contact formation region 20R shown in Fig. 10. 9 via a contact 454 included in the contact formation region 20S shown in FIG.

[0057] The multiple connection portions 19a individually connected to the array electrodes 20A, 20B, 20C, and 20D are interconnected via a common connection portion 19c located, for example, near the center of the array Un. The common connection portion 19c is provided in the same layer as the connection portions 19a. In the configuration shown in FIG. 1, the connection between the connection portion 19a and the electrode 15a is replaced with a connection between the common connection portion 19c and the electrode 15a (see FIG. 1) in this modified example. The specific form of the connection between the connection portion 19a and the electrode 15a is not limited to this and can be modified as appropriate. Furthermore, the number and arrangement of array electrodes such as the array electrodes 20A, 20B, 20C, and 20D are not limited to the example shown in FIG. 9 and can be modified as appropriate. For example, one of the array electrodes may be positioned above the common connection portion 19c from a planar perspective. In this case, a contact is provided to connect the array electrode to the common connection portion 19c. Furthermore, the more contacts that connect the connection portion 19a (or the common connection portion 19c) to one array electrode, the more current paths there are between the connection configurations, and the lower the electrical resistance of each individual contact can be, so from that perspective as well, it is possible to connect the array electrode using the common connection portion 19c and the contacts.

[0058] As shown in FIG. 9, the power supply line Vbias of the modified example extends in the second direction Dy in a position that is not in contact with the connection portion 19a and the signal line Sig. Specifically, the power supply line Vbias is provided along two of the four sides of the array Un that face the first direction Dx and extend in the second direction Dy. The power supply line Vbias and the third electrode 40A are connected via contacts 455 included in the contact formation region 45A shown in FIG. 10. Furthermore, a dummy electrode DF shown in FIG. 9 is disposed at a position corresponding to the position between the array electrode 20A and the array electrode 20C shown in FIG. 8. The dummy electrode DF is connected to the third electrode 40A via a contact 456, which is included in the contact formation region 45A shown in FIG. 10 and is located between the contact formation region 20P and the contact formation region 20R. The potential of the power supply line Vbias is applied to the dummy electrode DF via the contact in the contact formation region 45A and the third electrode 40A. This allows the electrical characteristics between array electrodes 20A and 20C to be closer to the electrical characteristics between array electrodes 20B and 20C, thereby improving the accuracy of detecting pressing force. Note that in Fig. 10, only two contacts in each region (contacts 451, 452, 453, 454, 455, 456) are given representative reference numerals, but contacts shown with the same shape as the square-shaped configurations to which the reference numerals are given also function as contacts.

[0059] In the first modification, adjacent arrays Un among the plurality of arrays Un arranged in a matrix form share the power supply line Vbias and the third electrode 40 located between them.

[0060] 9 is, for example, the fourth wiring layer 19 (see FIG. 1) in the embodiment, but is not limited to this and may be another wiring layer. In that case, the contacts shown in FIG. 10 and the contact holes for establishing connections through the contacts extend to the other wiring layer.

[0061] 8 to 10, four first electrodes (array electrodes 20A, 20B, 20C, and 20D) in the array Un share one second element 62, but in Modification 1, the number of first electrodes that can share one first element 61 is not limited to four, and may be two or more. Furthermore, the arrangement of the multiple first electrodes sharing one second element 62 from a planar viewpoint and the shape of each first electrode are arbitrary.

[0062] Except for the points noted above, Modification 1 is the same as the embodiment. That is, like the embodiment, an elastic body 50 and a second electrode 30 are provided on the electrode layer that forms the array electrodes 20A, 20B, 20C, and 20D and the third electrode 40A.

[0063] In a configuration in which a plurality of first electrodes share one first element 61, as in Modification 1, conduction similar to the conduction between the first electrode 20 and the second electrode 30 in the embodiment (see FIG. 2 ) occurs individually among the plurality of first electrodes in response to a pressing force from the second electrode 30 side. Therefore, there may be cases in which some of the plurality of first electrodes are in conduction with the second electrode 30, and cases in which all of the plurality of first electrodes are in conduction with the second electrode 30. That is, there may be cases in which at least one of the plurality of first electrodes is in conduction with the second electrode 30. For example, in a configuration in which array electrodes 20A, 20B, 20C, and 20D share one second element 62 as shown in FIG. 8, the following cases may occur: a first case in which none of array electrodes 20A, 20B, 20C, and 20D is electrically connected to second electrode 30; a second case in which one of array electrodes 20A, 20B, 20C, and 20D is electrically connected to second electrode 30; a third case in which two of array electrodes 20A, 20B, 20C, and 20D are electrically connected to second electrode 30; a fourth case in which three of array electrodes 20A, 20B, 20C, and 20D are electrically connected to second electrode 30; and a fifth case in which four of array electrodes 20A, 20B, 20C, and 20D are electrically connected to second electrode 30. The detection circuit connected to the signal line Sig has an electrical resolution capable of distinguishing between the first through fifth cases, allowing the pressure sensor to detect pressure in each array with gradation. That is, by individually detecting the first through fifth cases that may arise due to differences in the strength of the pressure from the second electrode 30, it is possible to detect not only the presence or absence of pressure but also the degree of pressure strength. While the first through fifth cases are used as an example here, the electrical resolution of the detection circuit need only correspond to the number of first electrodes sharing one second element 62.

[0064] According to the first modification, one transistor (second element 62) is connected to two or more first electrodes (e.g., array electrodes 20A, 20B, 20C, and 20D). This allows the intensity of the signal output to the signal line Sig via the transistor to vary depending on the number of first electrodes connected to the second electrode 30 among the two or more first electrodes. In other words, the signal intensity can be given a gradation depending on the number of first electrodes connected to the one transistor via the first element 61. This further improves the detection accuracy of the pressed portion and the pressing force within the detection area SA.

[0065] Furthermore, the third electrode 40 separates adjacent first electrodes in at least one direction among two or more first electrodes (for example, array electrodes 20A, 20B, 20C, 20D) connected to one transistor (second element 62). This makes it easier to stabilize the electrical characteristics due to the positional relationship between the two or more first electrodes connected to one transistor (second element 62) via the first element 61 and the third electrode 40.

[0066] The third electrode 40 is electrically connected to a power supply line Vbias that is stacked closer to the substrate 10 than the third electrode 40. This allows the power supply line Vbias to be disposed within the detection area SA and connected to the third electrode 40.

[0067] Furthermore, the power supply line Vbias is in the same layer as the signal line Sig, which allows the power supply line Vbias and the signal line Sig to be formed in the same process, thereby enabling the pressure sensor 1 to be manufactured at lower cost.

[0068] (Variation 2) FIG. 11 is a cross-sectional view of a laminated structure including the main components of a pressure sensor 1B according to Modification 2. The elastic body 50 shown in FIG. 11 is in a state in which it is receiving a pressing force from the second electrode 30 side. The pressure sensor 1B further includes a conductive portion 90 in addition to the components of the embodiment. As shown in FIG. 11, Modification 2 also includes a power supply line Vbias provided on the upper side of the coating portion HRC and exposed to the outside. The power supply line Vbias provided on the upper side of the coating portion HRC and exposed to the outside may be a post-installed electrode connected to an external power supply that applies the same potential as the power supply line Vbias of the embodiment, or may be a third electrode 40 extending to the outside.

[0069] The conductive portion 90 is, for example, a conductive tape that is provided on the second electrode 30 and the covering portion HRC and has a conductive and adhesive surface on the side of the power supply line Vbias that is exposed to the outside. As shown in Fig. 11, the conductive portion 90 connects the power supply line Vbias that is provided on the covering portion HRC and exposed to the outside to the second electrode 30. This applies the potential of the power supply line Vbias to the second electrode 30. The conductive portion 90 may have another configuration that functions in a similar manner.

[0070] In the second modification, when the pressure sensor 1B is not subjected to a pressing force from the second electrode 30 side, conduction between the first electrode 20 and the second electrode 30 is not established, as in the embodiment. Therefore, application of a potential to the power supply line Vbias from one side of the first element 61 is switched between on and off depending on whether a pressing force is applied. Therefore, the second modification can detect a pressing force in the same manner as the embodiment. Furthermore, according to the second modification, the second electrode 30 is always supplied with the potential of the power supply line Vbias. Therefore, when the pressure sensor 1B is subjected to a pressing force from the second electrode 30 side, the potential of the power supply line Vbias applied to the capacitor 70 (see FIG. 3 ) via the first element 61 can be more stabilized. Additionally, as in the embodiment, the first electrode 20 and the third electrode 40 are disposed adjacent to each other with the opening 25 interposed therebetween. Therefore, the electrical characteristics of the array are extremely stable regardless of the arrangement of the array in the row and column directions within the detection area SA. Therefore, according to the second modification, a pressing force can be detected with higher accuracy under more stable conditions.

[0071] As described above, according to the second modification, the second electrode 30 is connected to a power supply unit (power supply line Vbias) provided outside the area where the plurality of first electrodes 20 are provided. This allows the potential of the second electrode 30 to be set to the same potential as the third electrode 40 in advance, making it easier to stabilize the electrical characteristics of a switch (for example, switch 80) including the first electrode 20, the second electrode 30, and the third electrode 40 regardless of the arrangement of the switch.

[0072] In addition, other effects and advantages brought about by the aspects described in the embodiments and variants that are clear from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present disclosure. [Explanation of symbols]

[0073] 1,1B Pressure Sensor 10 Substrate 20 1st electrode 20A, 20B, 20C, 20D Array electrodes 30 2nd electrode 40,40A 3rd electrode 40a Extension 50 Elastic Body 51,51a,51b Conductive particles 62 Second element Gate scan line Sig signal line Vbias feed line

Claims

1. A substrate; a plurality of first electrodes provided on the substrate and arranged in a first direction and a second direction intersecting the first direction; a second electrode facing the plurality of first electrodes; a third electrode provided on the substrate and having a first lattice shape; an elastic body provided between the second electrode and the first electrode and the third electrode, the elastic body including conductive particles; a plurality of wiring layers connected to the first electrodes via contact holes provided in the substrate; Equipped with Each of the plurality of wiring layers has a second lattice shape that is different in size from the first lattice shape. Pressure sensor.

2. the plurality of wiring layers include a first wiring layer, a second wiring layer, a third wiring layer, and a fourth wiring layer arranged in a matrix; one corner of the first wiring layer, one corner of the second wiring layer, one corner of the third wiring layer, and one corner of the fourth wiring layer are connected to face each other; The pressure sensor according to claim 1 .

3. each of the plurality of wiring layers is connected to the corresponding first electrode at a plurality of lattice points of a second lattice shape; The pressure sensor according to claim 1 .

4. further comprising a power supply line extending in the second direction; the power supply line and the third electrode are connected via a contact. The pressure sensor according to claim 1 .

5. a dummy electrode disposed between the wiring layers arranged in the second direction and extending in the first direction; the dummy electrode is connected to the third electrode via a contact. The pressure sensor according to claim 1 .

6. a detection region in which the plurality of first electrodes are arranged in a matrix; the detection region includes a plurality of signal lines extending along one of a row direction and a column direction, and a plurality of scanning lines extending along the other of the row direction and the column direction; a transistor having one of a source and a drain connected to the first electrode, the other of the source and the drain connected to the signal line, and a gate connected to the scanning line; The pressure sensor according to claim 1 .

7. the plurality of first electrodes are formed in the same layer as the third electrode; The pressure sensor according to claim 1 .

8. the third electrode is continuous along the substrate so as to surround each of the first electrodes; The pressure sensor according to claim 1 .

9. The sheet resistance of the third electrode is smaller than the sheet resistance of the second electrode. The pressure sensor according to claim 1 .

10. the third electrode has an extension portion that extends outside an area where the plurality of first electrodes are provided and is connected to a power supply portion; The second electrode and the third electrode are electrically connected when a pressing force is applied. The pressure sensor according to claim 1 .

11. the second electrode is connected to a power supply portion provided outside a region in which the plurality of first electrodes are provided; The pressure sensor according to claim 1 .

12. The number of the first electrodes is two or more. One of the transistors is connected to two or more of the first electrodes. The pressure sensor according to claim 6.

13. the third electrode separates adjacent first electrodes in at least one direction from each other among the two or more first electrodes connected to one transistor; The pressure sensor of claim 12.

14. the third electrode is electrically connected to a power supply unit stacked on the substrate side of the third electrode; The pressure sensor of claim 12.

15. The signal line is on the same layer as the power supply part.

15. The pressure sensor of claim 14.

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