Pressure Sensor

Abstract

To provide a pressure sensor in which a sensor layer is provided on an array substrate while crosstalk is prevented.SOLUTION: A pressure sensor includes an array substrate in which a plurality of array electrodes are provided on a first surface, a counter substrate including a counter surface facing the first surface, a guard electrode disposed on the first surface and extending between the array electrodes, a sensor layer formed of conductive elastomer and overlapped on the first surface, the array electrodes, and the guard electrode, and a common electrode provided on the counter surface. The array substrate and the guard electrode have the same potential.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a pressure sensor. [Background technology]

[0002] The pressure sensor comprises an array substrate on which a plurality of array electrodes are provided, and an opposing substrate supporting a common electrode facing the array electrodes. The opposing substrate is a base material to which pressure is input, and is sometimes called a protective film. A sensor layer that covers the common electrode is provided on the surface of the opposing substrate facing the array electrodes. In the following patent document, the sensor layer is made of a conductive material in which a conductive material is mixed with an insulating rubber material. Elastomer Conductive Elastomer The electrode has the property that its electrical resistance decreases when it is deformed. In addition, in the following patent document, the sensor layer is separated from the array substrate when no pressure is applied to the opposing substrate. Therefore, when pressure is applied to the opposing substrate, the sensor layer comes into contact with the array electrode. Then, the sensor layer and the array electrode are electrically connected, and a current flows from the common electrode to the array electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-44937 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in order to simplify the manufacturing process and improve the accuracy of bonding the counter substrate to the array substrate, it has been considered to provide a sensor layer on the array electrode. However, when the sensor layer is provided on the array electrode, a current flows in a surface direction parallel to the sensor layer, causing crosstalk. On the other hand, to prevent crosstalk, it is considered to use an anisotropic conductive film as the sensor layer, in which a current flows only in the thickness direction of the sensor layer. However, when considering the dynamic range, it is difficult to provide a sensor layer with a conductive Elastomer A sensor layer with a thin film is preferred.

[0005] An object of the present invention is to provide a pressure sensor in which a sensor layer is provided on an array substrate while preventing crosstalk. [Means for solving the problem]

[0006] A pressure sensor according to one aspect of the present disclosure includes an array substrate having a plurality of array electrodes provided on a first surface thereof, an opposing substrate having an opposing surface opposing the first surface, a guard electrode disposed on the first surface and extending between the array electrodes, and a conductive Elastomer The array includes a sensor layer overlaid on the first surface, the array electrode, and the guard electrode, and a common electrode provided on the opposing surface. electrode and the guard electrode are at the same potential. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view schematically showing a pressure sensor according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 and viewed from the direction of the arrow. [Figure 3] FIG. 3 is a circuit diagram showing the circuit configuration of the pressure sensor of the first embodiment. [Figure 4] FIG. 4 is a plan view of the array substrate of the first embodiment as viewed from the sensor layer side. [Figure 5] FIG. 5 is a cross-sectional view showing a state in which the detection surface of the pressure sensor of the first embodiment is pressed. [Figure 6] FIG. 6 is a cross-sectional view showing a state in which a larger force is applied than in the state shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view showing a case where the array electrodes in the individual pressure detection regions are not connected to signal lines. [Figure 8] FIG. 8 is a cross-sectional view of a modified example of the pressure sensor of the first embodiment. [Figure 9]FIG. 9 is a plan view of the array substrate of the pressure sensor according to the first modification, viewed from the sensor layer side. [Figure 10] FIG. 10 is a plan view of the array substrate of the pressure sensor according to the second modification, viewed from the sensor layer side. [Figure 11] FIG. 11 is a plan view of the array substrate of the pressure sensor according to the third modification, viewed from the sensor layer side. [Figure 12] FIG. 12 is a plan view of the array substrate of the pressure sensor according to the fourth modification, viewed from the sensor layer side. [Figure 13] FIG. 13 is a plan view of the array substrate of the pressure sensor according to the fifth modification, viewed from the sensor layer side. [Figure 14] FIG. 14 is a plan view of the array substrate of the pressure sensor according to the sixth modification, viewed from the sensor layer side. [Figure 15] FIG. 15 is a plan view of the array substrate of the pressure sensor of the second embodiment, viewed from the common electrode side. [Figure 16] 16 is a cross-sectional view taken along the line XVI-XVI of FIG. 15, showing the state in which the detection surface of the pressure sensor of the second embodiment is pressed. [Figure 17] 17 is a cross-sectional view taken along the line XVII-XVII in FIG. 15, showing the pressure sensor of the second embodiment in a state where the detection surface is pressed. [Figure 18] FIG. 18 is a cross-sectional view showing a modified example of the pressure sensor of the second embodiment. [Figure 19] FIG. 19 is a plan view of the array substrate of the pressure sensor of the seventh modification, viewed from the common electrode side. [Figure 20] FIG. 20 is a cross-sectional view taken along the line XX-XX in FIG. [Figure 21] FIG. 21 is a plan view of the array substrate of the pressure sensor of the third embodiment, viewed from the common electrode side. [Figure 22] FIG. 22 is a cross-sectional view taken along the line XXII-XXII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Modes (embodiments) for implementing the pressure sensor of the present disclosure will be described in detail with reference to the drawings. The invention of the present disclosure is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially identical. Furthermore, the components described below can be combined as appropriate. Note that the disclosure is merely an example, and any appropriate modifications that a person skilled in the art can easily make while maintaining the gist of the invention are naturally included within the scope of the present invention. For clarity of explanation, the drawings may show the width, thickness, shape, etc. of each part more schematically than the actual embodiment. However, these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each figure, components similar to those previously described with reference to the previous figures are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0009] Furthermore, in this specification and claims, when expressing an aspect of placing another structure on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both a case in which another structure is placed directly on top of a certain structure so as to be in contact with the certain structure, and a case in which another structure is placed above a certain structure via yet another structure.

[0010] (Embodiment 1) FIG. 1 is a perspective view schematically showing a pressure sensor according to a first embodiment. As shown in FIG. 1, the pressure sensor 1 is a plate-shaped device. One surface of the pressure sensor 1 is a detection surface 1a. When the pressure sensor 1 is viewed from the normal direction of the detection surface 1a, the pressure sensor 1 has a rectangular shape (rectangular shape). The detection surface 1a of the pressure sensor 1 is divided into a detection region 2 that can detect pressure acting on the detection surface 1a, and a peripheral region 3 that surrounds the outside of the detection region 2. Note that a boundary line L is drawn in FIG. 1 to make it easier to understand the boundary between the detection region 2 and the peripheral region 3.

[0011] The detection area 2 is divided into a plurality of individual detection areas 4. In other words, the detection area 2 is a collection of a plurality of individual detection areas 4. The plurality of individual detection areas 4 are arranged in a first direction Dx and a second direction Dy. The first direction Dx is a direction parallel to the detection surface 1a. The second direction Dy is a direction parallel to the detection surface 1a and intersects with the first direction Dx. In this embodiment, the first direction Dx is a direction parallel to the short side 1b of the pressure sensor 1. The second direction Dy is a direction parallel to the long side 1c of the pressure sensor 1. In other words, in this embodiment, the first direction Dx and the second direction Dy are perpendicular to each other. In the following description, the direction perpendicular to each of the first direction Dx and the second direction Dy (the thickness direction of the pressure sensor 1) is referred to as a third direction Dz.

[0012] Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1, viewed from the direction of the arrow. Fig. 3 is a circuit diagram showing the circuit configuration of the pressure sensor of embodiment 1. As shown in Fig. 2, the pressure sensor 1 includes a substrate 5, an array layer 10, a guard electrode 30, a sensor layer 40, a common electrode 50, and a protective film 60.

[0013] The substrate 5 is an insulating substrate. For example, a glass substrate, a resin substrate, or a resin film is used for the substrate 5. In the following description, the upper side refers to one side of the third direction Dz, on the side where the array layer 10 is disposed as viewed from the substrate 5. The lower side refers to the other side of the third direction Dz, on the side where the substrate 5 is disposed as viewed from the array layer 10.

[0014] The array layer 10 is a layer on which a plurality of array electrodes 20 are provided. The plurality of array electrodes 20 are arranged in a detection region 2 in the array layer 10. A plurality of driving transistors 13 are provided in the detection region 2 of the array layer 10. The array layer 10 has various components for driving the driving transistors 13. Specifically, as shown in FIG. 1, the array layer 10 has a connection portion 7, a gate line driving circuit 8, a signal line selection circuit 9, gate lines 11 (see FIG. 3), and signal lines 12 (see FIG. 3). The array layer 10 and a substrate 5 are integrated to form an array substrate 6.

[0015] The connection section 7, the gate line driving circuit 8, and the signal line selection circuit 9 are arranged in the peripheral region 3 of the array layer 10. The connection section 7 is for connecting to a driving IC (Integrated Circuit) arranged outside the pressure sensor 1. In the present disclosure, the driving IC may be mounted as a COF (Chip On Film) on a flexible printed circuit board connected to the connection section 7 or on a rigid substrate. Alternatively, the driving IC may be mounted as a COG (Chip On Glass) in the peripheral region 3 of the substrate 5.

[0016] The gate line driving circuit 8 is a circuit that drives multiple gate lines 11 (see FIG. 3) based on various control signals from the driving IC. The gate line driving circuit 8 selects multiple gate lines 11 sequentially or simultaneously and supplies gate driving signals to the selected gate lines 11. The signal line selection circuit 9 is a switch circuit that selects multiple signal lines 12 (see FIG. 3) sequentially or simultaneously. The signal line selection circuit 9 is, for example, a multiplexer. Based on the selection signal supplied from the driving IC, the signal line selection circuit 9 connects the selected signal line 12 to the driving IC.

[0017] 3 is a circuit diagram showing the circuit configuration of the pressure sensor of Embodiment 1. As shown in FIG. 3, the gate line 11 extends in a first direction Dx in the array layer 10. A plurality of gate lines 11 are arranged in a second direction Dy. The signal line 12 extends in the array layer 10 in the second direction Dy. The plurality of signal lines 12 are arranged in the first direction Dx.

[0018] One driving transistor 13 is provided in each individual detection region 4. As shown in FIG. 2, the driving transistor 13 includes a semiconductor layer 13a, a gate insulating film 13b, a gate electrode 13c, a drain electrode 13d, and a source electrode 13e. The source electrode 13e is electrically connected to the array electrode 20. The gate electrode 13c is connected to the gate line 11. The drain electrode 13d is connected to the signal line 12. As a result, when the gate line 11 is scanned, the array electrode 20 and the signal line 12 are electrically connected. Therefore, the electrical signal (current value) input to the array electrode 20 is obtained via the signal line 12.

[0019] 1, a common wiring 25 and a common electrode wiring (not shown) are provided in the peripheral region 3 of the array layer 10. The common wiring 25 is a wiring for supplying a predetermined voltage to the common electrode 50, and extends along the peripheral region 3. The guard electrode wiring is a wiring for supplying a predetermined voltage to the guard electrode 30. The common wiring 25 and the guard electrode wiring (not shown) are connected to a driving IC via a connection portion 7, and a constant voltage is supplied from the driving IC.

[0020] 2, the first surface 6a of the array substrate 6 facing the protective film 60 is planarized by an insulating layer 14 that covers the driving transistors 13 and the like. In addition, spacers (not shown) that support the protective film 60 are provided in the peripheral region 3 of the first surface 6a of the array substrate 6.

[0021] 4 is a plan view of the array substrate of the first embodiment as viewed from the sensor layer side. The array electrodes 20 and the guard electrodes 30 are provided on the first surface 6a of the array substrate 6. The array electrodes 20 and the guard electrodes 30 are made of a metal material such as ITO (Indium Tin Oxide). As shown in FIG. 4, the array electrodes 20 are rectangular. The array electrodes 20 are arranged in the first direction Dx and the second direction Dy, and are disposed in the center of the individual detection region 4. Note that the shape of the array electrodes in the present disclosure is not limited to rectangular shapes.

[0022] 4, the guard electrode 30 includes a plurality of first guard electrodes 31 extending in a first direction Dx and a plurality of second guard electrodes 32 extending in a second direction Dy. The plurality of first guard electrodes 31 are arranged at equal intervals in the first direction Dx. The plurality of second guard electrodes 32 are arranged at equal intervals in the second direction Dy. Thus, the guard electrode 30 divides the detection area 2 into a matrix. Each of the areas divided into the matrix by the guard electrode 30 corresponds to an individual detection area 4. In other words, the array electrode 20 is arranged inside a rectangular frame formed by the first guard electrode 31 and the second guard electrode 32.

[0023] Although not particularly shown, an end of the first guard electrode 31 in the first direction Dx extends into the peripheral region 3. The end of the first guard electrode 31 in the first direction Dx is connected to guard electrode wiring (not shown). Similarly, an end of the second guard electrode 32 in the second direction Dy extends into the peripheral region 3. The end of the second guard electrode 32 in the second direction Dy is connected to guard electrode wiring (not shown). A constant voltage is supplied to the first guard electrode 31 and the second guard electrode 32 from the driving IC.

[0024] The sensor layer 40 is made of a conductive material in which a conductive material is mixed in a rubber material (base material) which is an insulator. Elastomer The sensor layer 40 has a high resistance when no pressure is applied. When pressure is applied to the sensor layer 40, the microparticles in the rubber material come into contact or come close to each other, and the resistance of the sensor layer 40 decreases. Furthermore, as the deformation of the rubber material increases, the amount of contact between the microparticles increases, and the resistance of the sensor layer 40 decreases significantly.

[0025] As shown in FIG. 2 , the sensor layer 40 is overlaid on the first surface 6 a of the array layer 10, the array electrodes 20, and the guard electrodes 30. In other words, the sensor layer 40 is a solid film that entirely covers the first surface 6 a, the array electrodes 20, and the guard electrodes 30. Therefore, the array electrodes 20 and the guard electrodes 30 are in contact with the sensor layer 40. The edges of the sensor layer 40 extend to the peripheral region 3. The edges of the sensor layer 40 are fixed to the array layer 10 by an adhesive layer or double-sided tape (not shown). Note that in the present disclosure, the sensor layer 40 may be disposed only in the detection region 2 and may not extend to the peripheral region 3. The sensor layer 40 of the present disclosure may also be formed by applying a coating to the first surface 6 a of the array layer 10, etc.

[0026] The protective film 60 is a highly insulating and flexible substrate. In the present disclosure, the protective film 60 may be referred to as an opposing substrate. The edges of the protective film 60 are fixed to spacers (not shown). This separates the protective film 60 from the array substrate 6 in the third direction Dz. The protective film 60 has an opposing surface 61 facing the array substrate 6 and a detection surface 1a facing the opposite direction from the opposing surface 61.

[0027] The common electrode 50 is a solid electrode formed on the entire opposing surface 61 of the protective film 60. It is connected to a common wiring 25 provided in the peripheral region 3 of the first surface 6a of the array substrate 6. The common electrode 50 is separated from the sensor layer 40. In other words, a gap S is provided between the common electrode 50 and the sensor layer 40. This allows the common electrode 50 to be insulated from the array electrode 20.

[0028] Next, a method of using the pressure sensor 1 will be described. The array electrode 20 and the guard electrode 30 are electrically connected via the sensor layer 40. When the pressure sensor 1 is in use, a voltage that is the same potential as that of the array electrode 20 is applied to the guard electrode 30 via guard electrode wiring (not shown). Therefore, no current flows from the guard electrode 30 to the array electrode 20. In other words, current flow to the array electrode 20 is prevented even when no pressure is input. Note that the potential of the array electrode 20 here refers to the potential of the array electrode 20 when a gate drive signal is input to the gate line 11 and the signal line 12 is connected to the array electrode. Meanwhile, a voltage is applied to the common electrode 50 via the common wiring 25 (see FIG. 1 ), setting it to a reference potential. This reference potential is higher than the potentials of the array electrode 20 and the guard electrode 30.

[0029] Fig. 5 is a cross-sectional view showing a state in which the detection surface of the pressure sensor of embodiment 1 is pressed. Fig. 6 is a cross-sectional view showing a state in which the detection surface is pressed with a force greater than that in the state of Fig. 5. Fig. 7 is a cross-sectional view showing a state in which the array electrodes in the pressed individual detection area are not connected to the signal lines. Next, a case in which a part of the detection surface 1a of the pressure sensor 1 is pressed will be described. In the following description, the pressed area among the multiple individual detection areas 4 will be referred to as the pressed individual detection area 4A, and the area adjacent to the pressed individual detection area 4A will be referred to as the adjacent individual detection area 4B.

[0030] As shown in FIG. 5, when the detection surface 1a of the pressure sensor 1 is pressed by a finger 200, a portion of the protective film 60 deforms to protrude downward. This causes the common electrode 50 to contact the sensor layer 40. Furthermore, when the array electrode 20 included in the individual pressure detection area 4A is connected to the signal line 12 (when the drive transistor 13 is ON), it is electrically connected to the common electrode 50 via the sensor layer 40. Therefore, a current flows through the array electrode 20 (see arrow A1 in FIG. 5). As a result, the current value input to the array electrode 20 is output from the signal line 12.

[0031] Furthermore, the array electrodes 20 included in the individual pressure detection area 4A are surrounded by guard electrodes 30 (first guard electrode 31 and second guard electrode 32). Therefore, current also flows through the guard electrodes 30 included in the individual pressure detection area 4A (see arrows A2 and A3 in FIG. 5). For this reason, the current flowing from the common electrode 50 hardly flows outside the rectangular frame of the guard electrodes 30. In other words, a current sufficient to operate the array electrodes 20 included in the adjacent individual detection area 4B as sensors does not flow.

[0032] Furthermore, when the pressure input to the detection surface 1a of the pressure sensor 1 is large, the protective film 60 protrudes downward more, as shown in Figure 6. As a result, the sensor layer 40 deforms so as to be recessed downward, and the resistance value of the deformed portion of the sensor layer 40 decreases. Furthermore, the contact point between the common electrode 50 and the sensor layer 40 becomes arc-shaped in cross section, increasing the contact area. As a result, the value of the current flowing through the array electrode 20 and guard electrode 30 included in the individual pressure detection area 4A increases.

[0033] On the other hand, as shown in Fig. 7, when the array electrode 20 in the individual pressure detection area 4A is not connected to the signal line 12 (when the drive transistor 13 is OFF), no current flows through this array electrode 20. However, the guard electrode 30 surrounding this array electrode 20 is at a predetermined potential. Therefore, a current flows through the guard electrode 30 (see arrows B1 and B2 in Fig. 7).

[0034] Furthermore, when the array electrode 20 included in the adjacent individual detection area 4B is connected to the signal line 12 (when the drive transistor 13 is ON), there is a possibility that a current will flow from the common electrode 50 via the sensor layer 40 (see dashed arrow B3 in FIG. 7). However, according to this embodiment, a guard electrode 30 is disposed between the contact point between the common electrode 50 and the sensor layer 40 and the array electrode 20 included in the adjacent individual detection area 4B. Therefore, the current flowing from the common electrode 50 flows toward the guard electrode 30, and hardly flows into the array electrode 20 included in the adjacent individual detection area 4B.

[0035] As described above, according to the pressure sensor 1 of the first embodiment, no current flows through the array electrodes 20 of the adjacent individual detection region 4B that is not pressed, thereby avoiding crosstalk.

[0036] FIG. 8 is a cross-sectional view of a modified example of the pressure sensor of embodiment 1. While the pressure sensor 1 of embodiment 1 has been described above, the pressure sensor of the present disclosure is not limited to one in which the sensor layer 40 is provided only on the array substrate 6. As shown in FIG. 8, the pressure sensor 1 may have an opposing sensor layer 70 provided on the opposing surface 61 of the protective film 60. The opposing sensor layer 70 is a solid film that covers the opposing surface 61 and the common electrode 50. Even in such a modified example, crosstalk can be suppressed in the same way as in embodiment 1. Furthermore, in the pressure sensor of the present disclosure, the guard electrode is not limited to the one exemplified in embodiment 1. Modified examples of the guard electrode are described below.

[0037] (Variation 1) FIG. 9 is a plan view of the array substrate of the pressure sensor according to Modification 1, viewed from the sensor layer. As shown in FIG. 9, the guard electrode 30A of Modification 1 has a ring-shaped annular guard electrode 33. The annular guard electrode 33 has a rectangular frame shape when viewed from the third direction Dz. The annular guard electrode 33 is located inside the individual detection region 4. The guard electrode 30A of Modification 1 does not extend into the peripheral region 3. Therefore, contact holes are formed in the array layer 10, and guard electrode wiring is provided in the contact holes to supply voltage to the guard electrode 30A. As described above, according to Modification 1, two sides of the annular guard electrode 33 are disposed between adjacent array electrodes 20. Therefore, crosstalk is less likely to occur than with the guard electrode 30 of Embodiment 1. In the present disclosure, the annular guard electrode may be in the shape of a circular frame.

[0038] (Variation 2) 10 is a plan view of the array substrate of the pressure sensor according to Modification 2, viewed from the sensor layer side. The guard electrode 30B of Modification 2 includes a plurality of first guard electrodes 31 extending in the first direction Dx, a plurality of second guard electrodes 32 extending in the second direction Dy, and a plurality of annular guard electrodes 33. In other words, the guard electrode 30B of Modification 1 is a combination of the guard electrode 30 of Embodiment 1 and the guard electrode 30A of Modification 1. This makes it possible to further suppress the occurrence of crosstalk.

[0039] (Variation 3) 11 is a plan view of the array substrate of the pressure sensor according to Modification 3, viewed from the sensor layer. The guard electrode 30C of Modification 3 includes a plurality of annular guard electrodes 33 and a plurality of connection guard electrodes 34. The connection guard electrodes 34 are electrodes that extend in the first direction Dx or the second direction Dy and connect the annular guard electrodes 33 to each other. The connection guard electrodes 34 also connect guard electrode wiring (not shown) arranged in the peripheral region 3 to the annular guard electrodes 33. Therefore, Modification 3 eliminates the need to form contact holes in the array layer 10, facilitating manufacturing.

[0040] (Variation 4) 12 is a plan view of the array substrate of a pressure sensor according to Modification 4, viewed from the sensor layer. The guard electrode 30D of Modification 4 includes a plurality of first guard electrodes 31, a plurality of second guard electrodes 32, a plurality of annular guard electrodes 33, and a plurality of connection guard electrodes 34. In Modification 4, the connection guard electrode 34 connects the annular guard electrode and the second guard electrode 32. This allows a predetermined voltage to be supplied to the annular guard electrode 33 via the first guard electrode 31. Furthermore, there is no need to form contact holes in the array layer 10, making manufacturing easier.

[0041] (Variation 5) FIG. 13 is a plan view of the array substrate of a pressure sensor according to Modification 5, viewed from the sensor layer. The guard electrode 30E of Modification 5 includes a multiple guard electrode 35. The multiple guard electrode 35 includes three (plural) annular guard electrodes 33 centered around the array electrode 20. The multiple guard electrode 35 of Modification 5 includes a first annular guard electrode 33a surrounding the outside of the array electrode 20, a second annular guard electrode 33b surrounding the outer periphery of the first annular guard electrode 33a, and a third annular guard electrode 33c surrounding the outer periphery of the second annular guard electrode 33b, forming a triple layer. The first annular guard electrode 33a, the second annular guard electrode 33b, and the third annular guard electrode 33c are narrower than the annular guard electrode 33 of Modification 1. With this multiple guard electrode 35, even if one of the three annular guard electrodes 33 is separated, the remaining annular guard electrodes 33 still function as annular guard electrodes 33.

[0042] (Variation 6) 14 is a plan view of the array substrate of a pressure sensor according to Modification 6, viewed from the sensor layer. The guard electrode 30F of Modification 6 includes a plurality of multiple guard electrodes 35 and a plurality of connection guard electrodes 34. The connection guard electrode 34 includes the multiple guard electrodes 35, which respectively connect the first annular guard electrode 33a, the second annular guard electrode 33b, and the third annular guard electrode 33c. The connection guard electrodes 34 are also connected to guard electrode wiring provided in contact holes in the array layer 10. Modification 6 eliminates the need to form contact holes for each of the plurality of annular guard electrodes 33, making manufacturing easier.

[0043] Next, another embodiment of the pressure sensor of the present disclosure will be described, focusing on the differences from the first embodiment.

[0044] (Embodiment 2) Fig. 15 is a plan view of the array substrate of the pressure sensor of embodiment 2 as viewed from the common electrode side. Fig. 16 is a cross-sectional view taken along the arrows XVI-XVI in Fig. 15, showing a state in which the detection surface of the pressure sensor of embodiment 2 is pressed. Fig. 17 is a cross-sectional view taken along the arrows XVII-XVII in Fig. 15, showing a state in which the detection surface of the pressure sensor of embodiment 2 is pressed. Fig. 18 is a cross-sectional view showing a modified example of the pressure sensor of embodiment 2.

[0045] 15, the pressure sensor 1G of the second embodiment differs from the pressure sensor 1 of the first embodiment in that it includes a sensor layer 40G instead of the sensor layer 40. In addition, the pressure sensor 1H of the second embodiment differs from the pressure sensor 1 of the first embodiment in that it includes a guard electrode 30G instead of the guard electrode 30.

[0046] The sensor layer 40G has a plurality of split sensor layers 41 that are split in the first direction Dx. Each of the split sensor layers 41 extends in the second direction Dy. That is, one split sensor layer 41 overlaps across a plurality of array electrodes 20 arranged in the second direction Dy. The split sensor layers 41 are spaced apart from one another. That is, a gap S1 is provided between the split sensor layers 41. Therefore, each of the split sensor layers 41 is insulated from the others.

[0047] The guard electrode 30G includes a plurality of cross guard electrodes 36 extending in the first direction Dx. The cross guard electrodes 36 are provided one by one between adjacent array electrodes 20 in the second direction Dy. When viewed from the third direction Dz (common electrode 50), the cross guard electrodes 36 intersect (are perpendicular to) the divided sensor layer 41.

[0048] According to the pressure sensor 1G of the second embodiment, when the detection surface 1a is pressed by the finger 200, the common electrode 50 comes into contact with the divided sensor layer 41 within the individual pressure detection region 4A, as shown in Fig. 16. As a result, the array electrode 20 in the individual pressure detection region 4A is electrically connected to the common electrode 50. Therefore, a current flows from the common electrode 50 to the array electrode 20 (see arrow C1 in Figs. 16 and 17).

[0049] 16, the array electrode 20 adjacent to the array electrode 20 in the individual pressure detection area 4A in the first direction Dx has a divided sensor layer 41 overlapped thereon that is different from the divided sensor layer 41 in contact with the common electrode 50. Therefore, almost no current flows through the array electrode 20 in the adjacent individual detection area 4B that is adjacent to the individual pressure detection area 4A in the first direction Dx (see dashed arrows C2 and C3 in FIG. 16).

[0050] 17, a cross guard electrode 36 is disposed between the array electrode 20 in the individual pressure detection area 4A and the array electrode 20 adjacent to this array electrode 20 in the second direction Dy. Therefore, almost no current flows through the array electrode 20 in the adjacent individual detection area 4B adjacent to the individual pressure detection area 4A in the second direction Dy (see dashed arrows C4 and C5 in FIG. 17).

[0051] As described above, in the pressure sensor 1G of the second embodiment, the guard electrode 30G and the divided sensor layer 41 suppress crosstalk.

[0052] The pressure sensor 1G of the second embodiment has been described above, but the pressure sensor of the present disclosure is not limited to the above. For example, as shown in FIG. 18, the pressure sensor 1G of the second embodiment may further include an opposing sensor layer 70. This opposing sensor layer 70 is a solid film that covers the entire opposing surface 61 and the common electrode 50. The pressure sensor of the present disclosure may have different sensitivities for each divided sensor layer 41. This will be described in detail in Modification 7 below.

[0053] (Variation 7) FIG. 19 is a plan view of the array substrate of the pressure sensor of Modification 7, viewed from the common electrode side. FIG. 20 is a cross-sectional view taken along the line XX-XX in FIG. 19. As shown in FIG. 19, the sensor layer 40H of the pressure sensor 1H of Modification 7 differs from that of Embodiment 2 in that it has two types of first divided sensor layers 41A and second divided sensor layers 41B. The individual detection region 4 of the pressure sensor 1H of Modification 7 also differs from that of the pressure sensor 1G of Embodiment 2 in that it is elongated in the first direction Dx and includes two array electrodes 20. Therefore, in the pressure sensor 1H of Modification 7, a pressing force (pressure) input to one individual detection region 4 is input to both the first divided sensor layer 41A and the second divided sensor layer 41B.

[0054] The first divided sensor layer 41A and the second divided sensor layer 41B are arranged alternately in the first direction Dx. Therefore, of the two array electrodes 20 included in one individual detection area 4, one is overlapped by the first divided sensor layer 41A and the other is overlapped by the second divided sensor layer 41B.

[0055] As shown in FIG. 20 , the first divided sensor layer 41A and the second divided sensor layer 41B are provided with protrusions 42 that protrude upward. The tips of the protrusions 42 are in contact with (abut against) the common electrode 50. The contact area between the protrusions 42 and the common electrode 50 is narrow. Therefore, the first divided sensor layer 41A and the second divided sensor layer 41B ensure insulation between the common electrode 50 and the array electrode 20. On the other hand, when the detection surface 1a is pressed and the protrusions 42 are crushed (deformed), the electrical resistance of the first divided sensor layer 41A and the second divided sensor layer 41B decreases. In other words, the first divided sensor layer 41A and the second divided sensor layer 41B change from an insulating state to a conductive state.

[0056] The first divided sensor layer 41A has two protrusions 42. The second divided sensor layer 41B has one protrusion 42. Therefore, the pressure acting on the protrusion 42 from the detection surface 1a is dispersed to the two protrusions 42 in the first divided sensor layer 41A. Therefore, even if the same pressure is applied, the amount of change is larger in the second divided sensor layer 41B.

[0057] According to the pressure sensor 1H of the seventh modification, the pressing force (pressure) input to the individual detection region 4 is input to both the first divided sensor layer 41A and the second divided sensor layer 41B. Furthermore, when the pressing force (pressure) is small, the two protrusions 42 of the first divided sensor layer 41A are not sufficiently crushed, and the first divided sensor layer 41A remains in an insulated state. Therefore, no current flows through the array electrode 20 that overlaps with the first divided sensor layer 41A. On the other hand, the protrusions 42 of the second divided sensor layer 41B are crushed to a large extent, and the second divided sensor layer 41B is in a conductive state. Therefore, current flows through the array electrode 20 that overlaps with the second divided sensor layer 41B.

[0058] On the other hand, when the pressing force (pressure) input to the individual detection area 4 is large, the two protrusions 42 of the first divided sensor layer 41A are significantly crushed, and the first divided sensor layer 41A becomes conductive. Therefore, a current flows through the array electrode 20 that overlaps with the first divided sensor layer 41A. In addition, the protrusions 42 of the second divided sensor layer 41B are also crushed, and a current also flows through the array electrode 20 that overlaps with the second divided sensor layer 41B.

[0059] In the pressure sensor 1H of the seventh modification, the sensitivity at which pressure can be detected can be changed by selecting a signal line 12. That is, by selecting, from among the multiple signal lines 12, a signal line 12 connected to an array electrode 20 overlapping with the second divided sensor layer 41B, small pressures can be detected. On the other hand, by selecting, from among the multiple signal lines 12, a signal line 12 connected to an array electrode 20 overlapping with the first divided sensor layer 41A, large pressures can be detected. That is, the range (dynamic range) at which pressure can be detected can be widened. Also, in the seventh modification, as in the second embodiment, almost no current flows between adjacent array electrodes 20. Therefore, crosstalk is suppressed.

[0060] The pressure sensor 1H of Modification 7 has been described above. While an example in which the number of protrusions is changed to form the divided sensor layers with different sensitivities has been given, the present disclosure is not limited to this. For example, a first divided sensor layer and a second divided sensor layer with different hardnesses may be used. Alternatively, a first divided sensor layer and a second divided sensor layer that change from an insulating state to a conductive state by changing their contact area depending on the magnitude of pressure may be used. In other words, as long as the pressure at which the divided sensor layers change from an insulating state to a conductive state differs, the method for achieving this is not particularly limited. Furthermore, the pressure sensor of the present disclosure may be configured by adding a solid opposing sensor layer 70 (see FIG. 18 ) that covers the common electrode 50 to the pressure sensor 1H of Modification 7. Next, a pressure sensor 1I of Embodiment 3 in which the opposing sensor layer 70 is modified will be described.

[0061] (Embodiment 3) Fig. 21 is a plan view of the array substrate of the pressure sensor of embodiment 3 as viewed from the common electrode side. Fig. 22 is a cross-sectional view taken along the line XXII-XXII in Fig. 21. As shown in Fig. 21, the opposing sensor layer 70I of the pressure sensor 1I of embodiment 3 includes a plurality of third divided sensor layers 71A and a plurality of fourth divided sensor layers 71B arranged alternately in the second direction Dy. The pressure sensor 1I of embodiment 3 also differs from modification 7 in that the individual detection region 4 is square-shaped and includes four array electrodes 20.

[0062] The third divided sensor layer 71A and the fourth divided sensor layer 71B are opposing divided sensor layers extending in the first direction Dx. The third divided sensor layer 71A and the fourth divided sensor layer 71B are divided into two parts in the second direction Dy. In other words, the third divided sensor layer 71A and the fourth divided sensor layer 71B are spaced apart from each other. Therefore, a gap S2 is provided between the third divided sensor layer 71A and the fourth divided sensor layer 71B. In other words, the third divided sensor layer 71A and the fourth divided sensor layer 71B are insulated from each other.

[0063] 22, the third divided sensor layer 71A is in contact with two protrusions 42 of the first divided sensor layer 41A and one protrusion 42 of the second divided sensor layer 41B. Although not particularly shown, the fourth divided sensor layer 71B is in contact with two protrusions 42 of the first divided sensor layer 41A and one protrusion 42 of the second divided sensor layer 41B.

[0064] In addition, the conductivity of the pressure sensor 1I Elastomer With respect to the rubber that is the base material of the third segment sensor layer 71A, the third segment sensor layer 71A is harder and less likely to deform. In other words, the third segment sensor layer 71A deforms and changes from an insulating state to a conductive state only when a pressure equal to or greater than a predetermined value is applied. On the other hand, the fourth segment sensor layer 71B deforms and changes from an insulating state to a conductive state even when a pressure less than the predetermined value is applied. Therefore, the third segment sensor layer 71A and the fourth segment sensor layer 71B have different sensitivities. Note that in this embodiment, the third segment sensor layer 71A and the fourth segment sensor layer 71B have different sensitivities from the first segment sensor layer 41A and the second segment sensor layer 41B, respectively.

[0065] Hereinafter, the array electrode 20 overlapping the third divided sensor layer 71A and the second divided sensor layer 41B will be referred to as the first array electrode 20A. The array electrode 20 overlapping the fourth divided sensor layer 71B and the second divided sensor layer 41B will be referred to as the second array electrode 20B. The array electrode 20 overlapping the third divided sensor layer 71A and the first divided sensor layer 41A will be referred to as the third array electrode 20C. The array electrode 20 overlapping the fourth divided sensor layer 71B and the first divided sensor layer 41A will be referred to as the fourth array electrode 20D.

[0066] Next, a method of using the pressure sensor 1 of embodiment 3 will be described. The magnitude of the input to the individual detection area 4 is divided into four stages, with the first stage being larger, followed by the second stage, the third stage, and the fourth stage.

[0067] According to the pressure sensor 1I of the third embodiment, when the pressure input to the individual detection region 4 is at the first stage (when the pressure is extremely small), for example, the third divided sensor layer 71A and the second divided sensor layer 41B are deformed and become conductive, causing a current to flow from the common electrode 50 to the first array electrode 20A.

[0068] When the pressure input to the individual detection area 4 reaches the second stage (when it becomes slightly larger), for example, the fourth divided sensor layer 71B and the second divided sensor layer 41B are deformed and become conductive, causing a current to flow from the common electrode 50 to the first array electrode 20A and the second array electrode 20B.

[0069] When the pressure input to the individual detection area 4 reaches a third stage (when it becomes even greater), for example, the third divided sensor layer 71A and the first divided sensor layer 41A are deformed and become conductive, causing current to flow from the common electrode 50 to the first array electrode 20A, the second array electrode 20B, and the third array electrode 20C.

[0070] When the pressure input to the individual detection area 4 reaches a fourth level (when it becomes even greater), for example, the fourth divided sensor layer 71B and the first divided sensor layer 41A are deformed and become conductive, causing current to flow from the common electrode 50 to the first array electrode 20A, the second array electrode 20B, the third array electrode 20C, and the fourth array electrode 20D.

[0071] According to the pressure sensor 1I of the third embodiment, the sensitivity for detecting pressure is divided into four stages. In other words, the range (dynamic range) for detecting the magnitude of pressure is expanded. Therefore, the magnitude of pressure to be detected can be set by selecting multiple gate lines 11 and multiple signal lines 12. Also, in the third embodiment, as in the second embodiment, almost no current flows between adjacent array electrodes 20, thereby suppressing crosstalk. [Explanation of symbols]

[0072] 1, 1G, 1H, 1I Pressure Sensors 1a Detection surface 2. Detection Area 3. Surrounding Areas 4 Individual detection areas 4A Individual pressure detection area 4B Adjacent individual detection area 5. Substrate 6 Array board 6a 1st page 10 Array Layer 11 Gate line 12 Signal line 13 Drive transistor 20 Array Electrodes 30, 30A, 30B, 30C, 30D, 30E Guard electrodes 31 First guard electrode 32 Second guard electrode 33 Annular guard electrode 34 Connection guard electrode 35 Multiple guard electrodes 36 Crossed guard electrodes 40, 40G, 40H sensor layer 41 divided sensor layer 41A First divided sensor layer 41B Second divided sensor layer 42 Protrusion 50 common electrode 60 Protective film 70 Opposite sensor layer 71A Third divided sensor layer (opposite divided sensor layer) 71B Fourth divided sensor layer (opposite divided sensor layer)

Claims

1. an array substrate having a plurality of array electrodes provided on a first surface; an opposing substrate having an opposing surface opposing the first surface; a guard electrode disposed on the first surface and extending between the array electrodes; a sensor layer made of a conductive elastomer and overlying the first surface, the array electrodes, and the guard electrodes; a common electrode provided on the opposing surface; Equipped with The array electrode and the guard electrode are at the same potential. Pressure sensor.

2. The sensor layer is a solid film that covers the first surface, the array electrodes, and the guard electrodes. The pressure sensor according to claim 1 .

3. The plurality of array electrodes are arranged in a first direction parallel to the first surface and in a second direction parallel to the first surface and intersecting the first direction; The guard electrode is a plurality of first guard electrodes extending in the first direction between the array electrodes adjacent to each other in the second direction; a plurality of second guard electrodes extending in the second direction between the array electrodes adjacent to each other in the first direction; and The array electrode is disposed inside a rectangular frame formed by the first guard electrode and the second guard electrode. The pressure sensor according to claim 2 .

4. the guard electrode includes a plurality of annular guard electrodes, The array electrode is disposed inside the annular guard electrode. The pressure sensor according to claim 2 or 3.

5. A plurality of the annular guard electrodes are provided around one of the array electrodes. The pressure sensor according to claim 4.

6. The plurality of array electrodes are arranged in a first direction parallel to the first surface and in a second direction parallel to the first surface and intersecting the first direction; the sensor layer is divided into a plurality of sensor layers in the first direction, each of which extends in the second direction; The guard electrode includes a plurality of intersecting guard electrodes extending in the first direction and intersecting the divided sensor layers when viewed from the common electrode. The pressure sensor according to claim 1 .

7. the divided sensor layer includes first divided sensor layers and second divided sensor layers alternately arranged in the first direction; The first divided sensor layer and the second divided sensor layer are different in pressure when they change from an insulating state to a conductive state. The pressure sensor according to claim 6.

8. The opposing substrate is provided with an opposing sensor layer made of a conductive elastomer and having a solid film that covers the entire opposing surface and the common electrode. The pressure sensor according to any one of claims 1 to 7.

9. the opposing substrate is provided with an opposing sensor layer made of a conductive elastomer and covering the entire opposing surface and the common electrode; the opposing sensor layer is divided into a plurality of opposing sensor layers in the second direction, each of which extends in the first direction; the opposing-side divided sensor layer includes a third divided sensor layer and a fourth divided sensor layer alternately arranged in the second direction, The first divided sensor layer, the second divided sensor layer, the third divided sensor layer, and the fourth divided sensor layer are different in pressure when the first divided sensor layer and the second divided sensor layer change from an insulating state to a conductive state. The pressure sensor according to claim 7.

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