Pressure sensor

Abstract

To provide a pressure sensor capable of detecting pressure changes over a wide pressure range.SOLUTION: A pressure sensor provided herein has multiple detection areas, each having a transistor, a detection electrode electrically connected to the transistor, and first and second pressure sensing layers arranged on the detection electrode, where the rate of change in resistance in response to pressure changes is different between the first and second pressure sensing layers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a pressure sensor. [Background technology]

[0002] Various pressure sensors capable of detecting pressure distribution have been proposed, and there is a demand for such pressure sensors that are capable of detecting pressure changes over a wide pressure range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-108952 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of this embodiment is to provide a pressure sensor that can detect changes in pressure over a wide pressure range. [Means for solving the problem]

[0005] According to one embodiment, the pressure sensor comprises a plurality of detection areas, each of which comprises a transistor, a detection electrode electrically connected to the transistor, and a first pressure-sensitive layer and a second pressure-sensitive layer arranged on the detection electrode, and the first pressure-sensitive layer and the second pressure-sensitive layer have different changes in resistance value with respect to changes in pressure. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a plan view showing an example of the configuration of a pressure sensor according to the first embodiment. [Figure 2] FIG. 2 is a plan view showing an example of the configuration of the pressure sensor shown in FIG. [Figure 3]FIG. 3 is a schematic cross-sectional view of the pressure sensor taken along line III-III in FIG. [Figure 4] FIG. 4 is a circuit diagram showing an example of the circuit configuration of the pressure sensor shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view for explaining a state in which the input surface of the pressure sensor shown in FIG. 1 is pressed. [Figure 6] FIG. 6 is a diagram showing an example of the relationship between the pressure applied to the input surface and the current value. [Figure 7] FIG. 7 is a diagram showing an example of the relationship between the pressure applied to the input surface and the current value. [Figure 8] FIG. 8 is a plan view showing an example of the configuration of the pressure sensor according to the second embodiment. [Figure 9] FIG. 9 is a schematic cross-sectional view of the pressure sensor taken along line IX-IX in FIG. [Figure 10] FIG. 10 is a plan view showing an example of the configuration of the pressure sensor according to the third embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view of the pressure sensor taken along line XI-XI in FIG. [Figure 12] FIG. 12 is a plan view showing an example of the pressure-sensitive layer of the pressure sensor of Configuration Example 1. As shown in FIG. [Figure 13] FIG. 13 is a plan view showing an example of the pressure-sensitive layer of the pressure sensor of Configuration Example 2. As shown in FIG. [Figure 14] FIG. 14 is a plan view showing an example of the pressure-sensitive layer of the pressure sensor of Configuration Example 3. As shown in FIG. [Figure 15] FIG. 15 is a diagram showing an example of the relationship between the pressure applied to the input surface and the current value. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present embodiment 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 make while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment for clarity of explanation, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, components that perform the same or similar functions as those described above with reference to the previous drawings are designated by the same reference numerals, and redundant detailed descriptions may be omitted as appropriate.

[0008] FIG. 1 is a plan view showing an example of the configuration of a pressure sensor 1 according to this embodiment. In one example, the first direction X, the second direction Y, and the third direction Z are perpendicular to one another, but they may intersect at an angle other than 90 degrees. The first direction X and the second direction Y correspond to directions parallel to the main surface of the substrate constituting the pressure sensor 1, and the third direction Z corresponds to the thickness direction of the pressure sensor 1. In this specification, the direction from the substrate 10 toward the insulating layer 40 is referred to as the "upper side" (or simply "up"), and the direction from the insulating layer 40 toward the substrate 10 is referred to as the "lower side" (or simply "lower"). When referring to a "second member above the first member" and a "second member below the first member," the second member may be in contact with the first member or may be spaced apart from the first member. Furthermore, the observation position for observing the pressure sensor 1 is assumed to be at the tip of the arrow indicating the third direction Z. Looking from this observation position toward the XY plane defined by the first direction X and the second direction Y is referred to as a planar view.

[0009] In this embodiment, the pressure sensor 1 is a pressure distribution sensor. The pressure sensor 1 includes a substrate 10. The substrate 10 is formed in a flat plate shape parallel to the XY plane. The substrate 10 has, for example, a rectangular shape in a plan view.

[0010] 1, the pressure sensor 1 includes a protective layer 80. The protective layer 80 is formed in the shape of a flat plate parallel to the XY plane. The substrate 10 and the protective layer 80 overlap each other in plan view.

[0011] The pressure sensor 1 has an input surface 1a on one side thereof to which pressure is applied. In the example shown in Fig. 1, the pressure sensor 1 has the input surface 1a on the surface of the protective layer 80 opposite to the surface facing the substrate 10. The pressure sensor 1 detects the pressure applied to the input surface 1a.

[0012] The input surface 1a includes a detection section 2 that detects pressure and a frame-shaped non-detection section 3 that surrounds the detection section 2. The detection section 2 includes a plurality of detection regions R. In the example shown in FIG. 1, the plurality of detection regions R are arranged side by side in the first direction X and the second direction Y.

[0013] The pressure sensor 1 further includes a connection portion 4, a gate line driving circuit 5, a signal line selection circuit 6, and a common wiring 7. The pressure sensor 1 also includes gate lines 8 and signal lines 9 (not shown). The connection portion 4, the gate line driving circuit 5, the signal line selection circuit 6, the common wiring 7, the gate lines 8, and the signal lines 9 are provided between a substrate 10 and a protective layer 80. The connection portion 4, the gate line driving circuit 5, the signal line selection circuit 6, and the common wiring 7 each overlap the non-detection portion 3 in a plan view.

[0014] The connecting portion 4 is for connecting the pressure sensor 1 to a driving IC (Integrated Circuit) (not shown) arranged outside the pressure sensor 1. The driving IC may be mounted as a COF (Chip On Film) on a flexible printed circuit board or a rigid board connected to the connecting portion 4. The driving IC may also be mounted as a COG (Chip On Glass) in an area of ​​the substrate 10 that overlaps with the non-detection portion 3.

[0015] The gate line driving circuit 5 is a circuit that drives the multiple gate lines 8 based on various control signals from the driving IC. The gate line driving circuit 5 selects the multiple gate lines 8 sequentially or simultaneously, and supplies gate driving signals to the selected gate lines 8.

[0016] The signal line selection circuit 6 is a switch circuit that sequentially or simultaneously selects multiple signal lines 9. The signal line selection circuit 6 is, for example, a multiplexer. The signal line selection circuit 6 connects the selected signal line 9 to the driving IC based on a selection signal supplied from the driving IC.

[0017] The common wiring 7 is a wiring for supplying a predetermined voltage to the common electrode, and is arranged along the outer edge 3a of the non-detection portion 3. The common wiring 7 is connected to the driving IC via the connection portion 4, and a constant voltage is supplied from the driving IC to the common wiring 7.

[0018] Fig. 2 is a plan view showing an example of the configuration of the pressure sensor 1 shown in Fig. 1. Here, a description will be given of the detection section 2 of the pressure sensor 1. In Fig. 2, the protective layer 80 is omitted.

[0019] The pressure sensor 1 includes a plurality of detection regions R, a common electrode 70, a plurality of gate lines 8, and a plurality of signal lines 9. The plurality of gate lines 8 are arranged side by side in the second direction Y and extend in the first direction X. The plurality of signal lines 9 are arranged side by side in the first direction X and extend in the second direction Y. In the example shown in FIG. 2, the plurality of detection regions R are arranged side by side in the first direction X and the second direction Y.

[0020] Each of the multiple detection regions R includes a detection electrode 50, a first pressure-sensitive layer 61, a second pressure-sensitive layer 62, a third pressure-sensitive layer 63, and a transistor 30 (not shown). In the example shown in Fig. 2, the detection electrode 50 has a rectangular shape in a plan view.

[0021] The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 each overlap the detection electrode 50. In the example shown in FIG. 2, the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are arranged in this order in the first direction X. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 have, for example, rectangular shapes with the same area as each other. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 as a whole have, for example, the same shape as the detection electrode 50.

[0022] 2, each of the plurality of detection regions R includes three different types of pressure-sensitive layers, namely, a first pressure-sensitive layer 61, a second pressure-sensitive layer 62, and a third pressure-sensitive layer 63, but is not limited to this. Each of the plurality of detection regions R may include at least two or more different types of pressure-sensitive layers, and may include four or more different types of pressure-sensitive layers.

[0023] The common electrode 70 overlaps the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 in a planar view. In the example shown in Fig. 2, the common electrode 70 overlaps each of the multiple detection regions R. The common electrode 70 overlaps, for example, the input surface 1a of the pressure sensor 1 in a planar view.

[0024] FIG. 3 is a schematic cross-sectional view of the pressure sensor 1 taken along line III-III in FIG.

[0025] The pressure sensor 1 includes a substrate 10, an insulating layer 20, a transistor 30, an insulating layer 40, a detection electrode 50, a first pressure-sensitive layer 61, a second pressure-sensitive layer 62, a third pressure-sensitive layer 63, a common electrode 70, and a protective layer 80. The pressure sensor 1 further includes a connection portion 4, a gate line driving circuit 5, a signal line selection circuit 6, and a common wiring 7 shown in FIG. 1. The pressure sensor 1 further includes a gate line 8 and a signal line 9 shown in FIG. 2.

[0026] The substrate 10 has a main surface (lower surface) 10A and a main surface (upper surface) 10B opposite to the main surface 10A. The main surfaces 10A and 10B are surfaces that are approximately parallel to the XY plane. An insulating layer 20 covers the main surface 10B. The transistors 30 are disposed on the insulating layer 20. The transistors 30 are disposed for each detection region R.

[0027] The transistor 30 includes a semiconductor layer 30a, a gate insulating film 30b, a gate electrode 30c, a drain electrode 30d, and a source electrode 30e. The semiconductor layer 30a is disposed on the insulating layer 20. The gate insulating film 30b is disposed on the semiconductor layer 30a. The gate electrode 30c is disposed on the gate insulating film 30b. The drain electrode 30d is disposed on the semiconductor layer 30a. The drain electrode 30d is electrically connected to a gate line 8 (not shown). The source electrode 30e is disposed on the semiconductor layer 30a. The source electrode 30e is electrically connected to a signal line 9 (not shown).

[0028] The insulating layer 40 covers the insulating layer 20 and the transistor 30. The insulating layer 40 has a surface 40B facing the protective layer 80. The surface 40B is planarized. Although not shown, the connection portion 4, the gate line driving circuit 5, the signal line selection circuit 6, the common wiring 7, the gate lines 8, and the signal lines 9 are provided between the main surface 10B and the surface 40B.

[0029] The detection electrodes 50 are arranged on the surface 40B. The detection electrodes 50 are arranged in each detection region R. The surface 40B is exposed between adjacent detection electrodes 50. The detection electrodes 50 are electrically connected to the drain electrode 30d, and are electrically connected to the transistor 30.

[0030] The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are disposed on the detection electrode 50. In the example shown in FIG. 3, the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are disposed on the detection electrode 50 in this order, aligned in the first direction X. In the example shown in FIG. 3, the first pressure-sensitive layer 61 and the second pressure-sensitive layer 62 are in contact with each other, but this is not a limitation, and the first pressure-sensitive layer 61 and the second pressure-sensitive layer 62 may be spaced apart. Furthermore, the second pressure-sensitive layer 62 and the third pressure-sensitive layer 63 are in contact with each other, but this is not a limitation, and the second pressure-sensitive layer 62 and the third pressure-sensitive layer 63 may be spaced apart.

[0031] The common electrode 70 is disposed on the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63. The common electrode 70 has a surface 70A facing the substrate 10 and a surface 70B opposite to the surface 70A. A protective layer 80 covers the surface 70B. The common electrode 70 is, for example, a metal film deposited on the surface of the protective layer 80 opposite the input surface 1a. Note that the pressure sensor 1 does not necessarily have to include the protective layer 80, in which case the surface 70B of the common electrode 70 becomes the input surface 1a.

[0032] Focusing on the two adjacent detection regions R1 and R2, the pressure sensor 1 has a gap S between the surface 40B and the surface 70A between the detection region R1 and the detection region R2. In the example shown in Fig. 3, the detection electrode 50 in the detection region R1 is adjacent to the detection electrode 50 in the detection region R2 across the gap S. Furthermore, the third pressure-sensitive layer 63 in the detection region R1 is adjacent to the first pressure-sensitive layer 61 in the detection region R2 across the gap S.

[0033] 2 and 3, the detection electrode 50 and the common electrode 70 are arranged to face each other. In other words, the pressure sensor 1 includes so-called opposed electrodes.

[0034] The substrate 10 is a substrate or film having insulating properties. The substrate 10 is a substrate or film made of, for example, glass or resin. The insulating layers 20, 40 are inorganic or organic insulating films. The protective layer 80 is a substrate or film having insulating properties and flexibility. The protective layer 80 is a substrate or film made of, for example, resin.

[0035] The detection electrode 50 and the common electrode 70 are electrodes formed from a metal material such as indium tin oxide (ITO).

[0036] Each of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 is formed of an insulating resin containing a conductive material. The conductive material is, for example, fine particles having conductivity. The conductive material is dispersed in the insulating resin and is spaced apart from one another. Each of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 is, for example, a conductive elastomer in which a conductive material is mixed into a rubber material. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 may be formed, for example, by applying an insulating resin material containing a conductive material using an inkjet or the like.

[0037] A pressure-sensitive layer formed from an insulating resin containing such a conductive material has a high resistance value when no pressure is applied, because the conductive materials contained in the insulating resin are separated from each other. When pressure is applied to the pressure-sensitive layer, the insulating resin deforms, and the conductive materials contained in the insulating resin come into contact or approach each other, thereby reducing the resistance value of the pressure-sensitive layer. When further pressure is applied to the pressure-sensitive layer and the amount of deformation of the insulating resin increases, the amount of conductive material that comes into contact or proximity with each other increases, further reducing the resistance value of the pressure-sensitive layer. In this way, the resistance value of a pressure-sensitive layer formed from an insulating resin containing a conductive material changes in response to changes in pressure.

[0038] The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 have different resistance changes in response to pressure changes. For example, the resistance changes in response to pressure changes may be made different by varying the content of conductive material contained in the insulating resin. Alternatively, the resistance changes in response to pressure changes may be made different by varying the conductivity of the conductive material contained in the insulating resin. Alternatively, the resistance changes in response to pressure changes may be made different by varying the hardness of the insulating resin.

[0039] Fig. 4 is a circuit diagram showing an example of the circuit configuration of the pressure sensor 1 shown in Fig. 1. As shown in Fig. 4, the gate electrode 30c is electrically connected to the gate line 8. Furthermore, the source electrode 30e is electrically connected to the signal line 9. In other words, the transistor 30 is electrically connected to the gate line 8 and the signal line 9.

[0040] The gate lines 8 extend in the first direction X and are electrically connected to each of the transistors 30 in the multiple detection regions R aligned in the first direction X. The signal lines 9 extend in the second direction Y, intersect with the gate lines 8, and are electrically connected to each of the transistors 30 in the multiple detection regions R aligned in the second direction Y. The detection electrode 50 is electrically connected to the drain electrode 30d.

[0041] When the gate line 8 is scanned, the detection electrode 50 and the signal line 9 are electrically connected. As a result, the value of the current flowing between the detection electrode 50 and the common electrode 70 can be obtained via the signal line 9. From the obtained current value, the pressure applied to the input surface 1a can be detected.

[0042] 5 is a cross-sectional view for explaining a state in which the input surface 1a of the pressure sensor 1 is pressed. In FIG. 5, the transistor 30 is omitted.

[0043] When the input surface 1a of the pressure sensor 1 is not pressed, each of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 has a large resistance value. The detection electrode 50 and the common electrode 70 overlap in the third direction Z via the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, or the third pressure-sensitive layer 63. Therefore, when the input surface 1a is not pressed, the detection electrode 50 and the common electrode 70 are not electrically connected.

[0044] 5, when the input surface 1a is pressed by, for example, a finger, pressure is applied to the input surface 1a in the direction from the protective layer 80 toward the substrate 10, i.e., in the direction A1. At this time, the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are each compressed in the direction A1, and the conductive materials contained in the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 come into contact with or close to each other. As a result, the resistance value of each of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 decreases, and a current flows between the detection electrode 50 and the common electrode 70.

[0045] As the pressure applied to the input surface 1a in the A1 direction increases, each of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 is further compressed in the A1 direction, and the amount of conductive material in contact with or close to each other increases. This further reduces the resistance value of each of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63, and increases the current flowing between the detection electrode 50 and the common electrode 70. In other words, as the pressure applied to the input surface 1a increases, the value of the current flowing between the detection electrode 50 and the common electrode 70 increases. By detecting this change in the current value, it is possible to detect changes in the pressure applied to the input surface 1a.

[0046] 6 and 7 are diagrams showing an example of the relationship between the pressure P applied to the input surface 1a and the current value C. In FIG. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 have different resistance changes in response to changes in pressure P. For this reason, as shown in Fig. 6, for example, the current C changes in response to changes in pressure P differently for the current C1 flowing through the first pressure-sensitive layer 61, the current C2 flowing through the second pressure-sensitive layer 62, and the current C3 flowing through the third pressure-sensitive layer 63.

[0047] In a pressure sensor 1 having a first pressure-sensitive layer 61, a second pressure-sensitive layer 62, and a third pressure-sensitive layer 63, the current value C flowing between the detection electrode 50 and the common electrode 70 is obtained, for example, as shown in Figure 7, as the average value of the current value C1 flowing through the first pressure-sensitive layer 61, the current value C2 flowing through the second pressure-sensitive layer 62, and the current value C3 flowing through the third pressure-sensitive layer 63.

[0048] According to this embodiment, it is possible to provide a pressure sensor that can detect changes in pressure over a wide pressure range. The pressure sensor 1 includes a plurality of detection regions R. Each of the plurality of detection regions R includes a first pressure-sensitive layer 61 and a second pressure-sensitive layer 62. The first pressure-sensitive layer 61 and the second pressure-sensitive layer 62 have different resistance values ​​that change with pressure. Therefore, the current C1 flowing through the first pressure-sensitive layer 61 and the current C2 flowing through the second pressure-sensitive layer 62 change in a different manner with respect to a change in pressure P applied to the input surface 1a. Therefore, the first pressure-sensitive layer 61 and the second pressure-sensitive layer 62 have different detectable pressure ranges and sensitivities. In the example shown in FIG. 6 , the first pressure-sensitive layer 61 can detect changes in pressure P with high sensitivity in a low-pressure range. The second pressure-sensitive layer 62 has lower sensitivity at low pressures than the first pressure-sensitive layer 61, but can detect changes in pressure P over a wider pressure range than the first pressure-sensitive layer 61. In the pressure sensor 1 including such a first pressure-sensitive layer 61 and a second pressure-sensitive layer 62, the current value C flowing between the detection electrode 50 and the common electrode 70 is obtained, for example, as the average value of the current values ​​C1 and C2. Therefore, the pressure sensor 1 including the first pressure-sensitive layer 61 and the second pressure-sensitive layer 62 can detect changes in pressure P over a wider pressure range than a pressure sensor including only the first pressure-sensitive layer 61. Furthermore, the pressure sensor 1 can detect changes in pressure P at low pressures with better sensitivity than a pressure sensor including only the second pressure-sensitive layer 62.

[0049] As described above, according to this embodiment, a pressure sensor capable of detecting pressure changes over a wide pressure range can be provided, and the detection sensitivity of the pressure sensor can be improved within a desired pressure range.

[0050] (Second embodiment) Fig. 8 is a plan view showing an example of the configuration of a pressure sensor 1 according to the second embodiment. The description above is used to cite the same configuration as in the first embodiment, and a description will be omitted. Here, the detection unit 2 of the pressure sensor 1 will be described. In Fig. 8, the protective layer 80 is omitted.

[0051] Each of the multiple detection regions R includes a detection electrode 50, a first pressure-sensitive layer 61, a second pressure-sensitive layer 62, a third pressure-sensitive layer 63, a common electrode 70, and a transistor 30 (not shown). The detection electrode 50 includes one electrode 50a extending in the second direction Y and multiple electrodes 50b extending from the electrode 50a in the first direction X. The common electrode 70 includes one electrode 70a extending in the second direction Y and multiple electrodes 70b extending from the electrode 70a in the first direction X. The electrodes 50b and the electrodes 70b are arranged alternately in the second direction Y. In the example shown in FIG. 8, three of each of the electrodes 50b and the electrodes 70b are arranged in each detection region R.

[0052] The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 each overlap the detection electrode 50 and the common electrode 70. In the example shown in FIG. 8, the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 each overlap one of the plurality of electrodes 50b and one of the plurality of electrodes 70b. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are, for example, arranged in this order in the second direction Y. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 each have, for example, a rectangular shape with the same area. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 as a whole have a rectangular shape.

[0053] FIG. 9 is a schematic cross-sectional view of the pressure sensor 1 taken along line IX-IX in FIG.

[0054] The detection electrodes 50 and the common electrode 70 are disposed on the surface 40B. The electrodes 50b of the detection electrodes 50 and the electrodes 70b of the common electrode 70 are disposed alternately in the second direction Y.

[0055] The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are disposed on the detection electrode 50 and the common electrode 70. In the example shown in FIG. 9 , the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are disposed side by side in this order in the second direction Y. Each of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 covers one of the plurality of electrodes 50b and one of the plurality of electrodes 70b. Between the electrode 50b and the electrode 70b, the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are in contact with the surface 40B.

[0056] The protective layer 80 covers the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63. The pressure sensor 1 does not necessarily have to include the protective layer 80. In this case, the surfaces of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 opposite to the surfaces facing the surface 40B become the input surface 1a.

[0057] Focusing on the two adjacent detection regions R1 and R2, the pressure sensor 1 has a gap S between the detection regions R1 and R2, and between the surface 40B and the surface of the protective layer 80 facing the surface 40B. In the example shown in Fig. 9, the third pressure-sensitive layer 63 of the detection region R1 is adjacent to the first pressure-sensitive layer 61 of the detection region R2, with the gap S interposed therebetween.

[0058] 8 and 9, the detection electrode 50 and the common electrode 70 are arranged on the same plane. That is, the pressure sensor 1 includes so-called parallel electrodes.

[0059] The pressure sensor 1 according to the second embodiment also provides the same effects as those of the first embodiment.

[0060] (Third embodiment) 10 is a plan view showing an example of the configuration of a pressure sensor 1 according to the third embodiment. The description above is used to omit the description of the same configuration as in the first embodiment. Here, the detection unit 2 of the pressure sensor 1 will be described. In FIG. 8, the common electrode 70 and the protective layer 80 are omitted.

[0061] The pressure sensor 1 includes a plurality of detection regions R. Each of the detection regions R includes a detection electrode 50, a first pressure-sensitive layer 61, a second pressure-sensitive layer 62, a third pressure-sensitive layer 63, and a transistor 30 (not shown). The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 overlap with the detection electrode 50. In the example shown in FIG. 10 , the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are aligned in this order in the first direction X. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 have, for example, rectangular shapes with the same area as each other. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 have, for example, the same shape as the detection electrode 50 as a whole.

[0062] The pressure sensor 1 further includes a partition 90. The partition 90 is disposed between two adjacent detection regions R. In the example shown in FIG. 10 , the partition 90 includes a plurality of first partitions 90a arranged side by side in the second direction Y and extending in the first direction X, and a plurality of second partitions 90b arranged side by side in the first direction X and extending in the second direction Y. Two first partitions 90a are arranged between each pair of adjacent detection regions R in the second direction Y. Two second partitions 90b are arranged between each pair of adjacent detection regions R in the first direction X. The intersecting first partitions 90a and second partitions 90b are connected to each other. As a result, the partitions 90 as a whole are formed in a lattice shape surrounding each of the multiple detection regions R.

[0063] FIG. 11 is a schematic cross-sectional view of the pressure sensor 1 taken along line XI-XI in FIG.

[0064] The detection electrodes 50 are arranged on the surface 40B for each detection region R. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are arranged on the detection electrodes 50. In the example shown in FIG. 11 , the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are arranged in this order on the detection electrodes 50, lined up in the first direction X. The common electrode 70 is arranged on the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, the third pressure-sensitive layer 63, and the partition wall 90.

[0065] The partition 90 is disposed on the surface 40B between the adjacent detection regions R1 and R2. The partition 90 has a side surface 90S facing the pressure-sensitive layer. In the example shown in FIG. 11, the side surface 90S contacts the side surface of the first pressure-sensitive layer 61 or the third pressure-sensitive layer 63. The pressure sensor 1 has a gap S between the surface 40B and the surface 70A between the adjacent partitions 90. The partition 90 is formed of, for example, an insulating material.

[0066] The pressure sensor 1 according to the third embodiment may be applied to a pressure sensor 1 having, for example, parallel electrodes. The pressure sensor 1 according to the third embodiment also provides the same effects as the first embodiment.

[0067] (Example of pressure-sensitive layer configuration) (Configuration example 1) Fig. 12 is a plan view showing an example of the pressure-sensitive layer of the pressure sensor 1 of Configuration Example 1. The description of the same configuration as in the first embodiment will be omitted by citing the above description. In Fig. 12, one detection region R is shown. The detection electrode 50, common electrode 70, and protective layer 80 are also omitted.

[0068] Each of the multiple detection regions R includes a first pressure-sensitive layer 61, a second pressure-sensitive layer 62, and a third pressure-sensitive layer 63. In the example shown in FIG. 12, the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 are arranged in this order in the first direction X, but this is not limited to this. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 have the same area. That is, in the example shown in FIG. 12, the area ratio of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 (first pressure-sensitive layer 61:second pressure-sensitive layer 62:third pressure-sensitive layer 63) is 1:1:1. The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 have, for example, a rectangular shape.

[0069] (Configuration example 2) Fig. 13 is a plan view showing an example of the pressure-sensitive layer of the pressure sensor 1 of Configuration Example 2. The description above is used to omit the description of the same configuration as in Configuration Example 1. Fig. 13 shows one detection region R. The detection electrode 50, common electrode 70, and protective layer 80 are also omitted.

[0070] The pressure sensor 1 of Configuration Example 2 differs from Configuration Example 1 in that the first pressure-sensitive layer 61 has an area different from the second pressure-sensitive layer 62 and the third pressure-sensitive layer 63. The first pressure-sensitive layer 61 has, for example, an area larger than the second pressure-sensitive layer 62. In the example shown in FIG. 13, the first pressure-sensitive layer 61 is twice as large as the second pressure-sensitive layer 62. Furthermore, the third pressure-sensitive layer 63 has the same area as the second pressure-sensitive layer 62. That is, in the example shown in FIG. 13, the area ratio of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 (first pressure-sensitive layer 61:second pressure-sensitive layer 62:third pressure-sensitive layer 63) is 2:1:1.

[0071] (Configuration example 3) Fig. 14 is a plan view showing an example of the pressure-sensitive layer of the pressure sensor 1 of Configuration Example 3. The description above is used to omit the description of the same configuration as in Configuration Example 1. Fig. 14 shows one detection region R. The detection electrode 50, common electrode 70, and protective layer 80 are also omitted.

[0072] The pressure sensor 1 of Configuration Example 3 differs from Configuration Example 1 in that the third pressure-sensitive layer 63 has an area different from the first pressure-sensitive layer 61 and the second pressure-sensitive layer 62. The third pressure-sensitive layer 63 has, for example, an area larger than the first pressure-sensitive layer 61. In the example shown in FIG. 14, the third pressure-sensitive layer 63 is twice the size of the first pressure-sensitive layer 61. Furthermore, the second pressure-sensitive layer 62 has the same area as the first pressure-sensitive layer 61. That is, in the example shown in FIG. 14, the area ratio of the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 (first pressure-sensitive layer 61:second pressure-sensitive layer 62:third pressure-sensitive layer 63) is 1:1:2.

[0073] Each of the multiple detection regions R of the pressure sensors 1 of configuration examples 1 to 3 shown in Figures 12 to 14 includes three different types of pressure-sensitive layers, namely, the first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63, but is not limited to this. The detection region R may include at least two or more different types of pressure-sensitive layers, and may also include four or more different types of pressure-sensitive layers. The pressure-sensitive layers according to configuration examples 1 to 3 shown in Figures 12 to 14 can be applied to, for example, an opposed-type pressure sensor 1 and a parallel-type pressure sensor 1.

[0074] Fig. 15 is a diagram showing an example of the relationship between the pressure P applied to the input surface 1a and the current value C flowing between the detection electrode 50 and the common electrode 70 in the pressure sensors 1 of configuration examples 1 to 3 shown in Figs. 12 to 14. The current value C of the pressure sensor 1 of configuration example 1 shown in Fig. 12 is shown by a solid line, the current value C of the pressure sensor 1 of configuration example 2 shown in Fig. 13 is shown by a dashed line, and the current value C of the pressure sensor 1 of configuration example 3 shown in Fig. 14 is shown by a dashed line.

[0075] The first pressure-sensitive layer 61, the second pressure-sensitive layer 62, and the third pressure-sensitive layer 63 have different resistance values ​​that change with a change in pressure P. Therefore, as shown in FIG. 6, for example, the current C1 flowing through the first pressure-sensitive layer 61, the current C2 flowing through the second pressure-sensitive layer 62, and the current C3 flowing through the third pressure-sensitive layer 63 change in a different manner with respect to a change in pressure P. In the example shown in FIG. 6, the first pressure-sensitive layer 61 can detect changes in pressure P at low pressures with better sensitivity than the second pressure-sensitive layer 62 and the third pressure-sensitive layer 63. The third pressure-sensitive layer 63 can detect changes in pressure P at high pressures with better sensitivity than the first pressure-sensitive layer 61 and the second pressure-sensitive layer 62.

[0076] In the pressure sensor 1 shown in Fig. 13, the area of ​​the first pressure-sensitive layer 61, which can sensitively detect changes in pressure P at low pressures, is larger than the areas of the other pressure-sensitive layers. Therefore, as shown in Fig. 15, the pressure sensor 1 shown in Fig. 13 can sensitively detect changes in pressure P at low pressures more than the pressure sensor 1 shown in Fig. 12, in which each pressure-sensitive layer has the same area.

[0077] In the pressure sensor shown in Fig. 14, the area of ​​the third pressure-sensitive layer 63, which can sensitively detect changes in pressure P at high pressures, is larger than the areas of the other pressure-sensitive layers. Therefore, as shown in Fig. 15, the pressure sensor 1 shown in Fig. 14 can sensitively detect changes in pressure P at high pressures more than the pressure sensor 1 shown in Fig. 12, in which each pressure-sensitive layer has the same area.

[0078] In this way, by changing the area of ​​the pressure-sensitive layer, the detection sensitivity of the pressure sensor can be further improved within a desired pressure range. Furthermore, the pressure sensors 1 of Configuration Examples 1 to 3 also provide the same effects as those of the first embodiment.

[0079] As described above, according to this embodiment, it is possible to provide a pressure sensor that can detect changes in pressure over a wide pressure range.

[0080] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in each embodiment. For example, some components may be omitted from all the components shown in each embodiment. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0081] 1...Pressure sensor 2...Detection part 3...Non-detection part 4...Connection portion 5...Gate line driving circuit 6...Signal line selection circuit 7...Common wiring 8...Gate line 9...Signal line 10...substrate 20...insulating layer 30...transistor 40...insulating layer 50...Detection electrode 61, 62, 63...Pressure-sensitive layer 70...Common electrode 80...Protective layer R: Detection area

Claims

1. a plurality of detection areas; each of the plurality of detection regions includes a transistor, a detection electrode electrically connected to the transistor, and a first pressure-sensitive layer and a second pressure-sensitive layer disposed on the detection electrode; The first pressure-sensitive layer and the second pressure-sensitive layer have different resistance values ​​in response to pressure changes. Pressure sensor.

2. The pressure sensor according to claim 1 , wherein the first pressure-sensitive layer and the second pressure-sensitive layer have the same area in a plan view.

3. The pressure sensor according to claim 1 , wherein the first pressure-sensitive layer and the second pressure-sensitive layer have different areas in a plan view.

4. Furthermore, a plurality of gate lines extending in a first direction; a plurality of signal lines extending in a second direction perpendicular to the first direction, The pressure sensor according to claim 1 , wherein each of the plurality of detection regions is aligned in the first direction and the second direction.

5. The pressure sensor according to claim 4 , wherein the first pressure-sensitive layer and the second pressure-sensitive layer are aligned in the first direction.

6. The pressure sensor according to claim 4 , wherein the first pressure-sensitive layer and the second pressure-sensitive layer are aligned in the second direction.

7. The pressure sensor of claim 1 , further comprising a common electrode disposed on the first pressure sensitive layer and the second pressure sensitive layer.

8. an insulating layer covering the transistor; a common electrode disposed on the insulating layer; The pressure sensor of claim 1 , wherein the sensing electrode is disposed on the insulating layer.

9. an insulating layer covering the transistor; The pressure sensor according to claim 1 , further comprising: a partition wall disposed on the insulating layer.

10. The pressure sensor according to claim 1 , wherein the first pressure-sensitive layer and the second pressure-sensitive layer are formed of an insulating resin containing a conductive material.

11. The pressure sensor according to claim 10 , wherein the first pressure-sensitive layer has a different content of the conductive material contained in the insulating resin than the second pressure-sensitive layer.

12. The pressure sensor according to claim 10 , wherein the first pressure-sensitive layer has a different conductivity from the second pressure-sensitive layer, the conductive material being contained in the insulating resin.

13. The pressure sensor according to claim 10 , wherein the insulating resin of the first pressure-sensitive layer has a hardness different from that of the second pressure-sensitive layer.

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