Capacitive touch sensor and capacitive touch sensor module

Abstract

To provide an electrostatic capacitance type touch sensor in which design is easy; manufacture is simple; separation or disconnection of an electrode or a wire is suppressed even if following a three-dimensional shape such as a curved surface or an uneven surface; and decrease in detection accuracy can be suppressed.SOLUTION: In an electrostatic capacitance type touch sensor including a detection electrode and a wire provided on a base material sheet, a first deformation suppression layer covering the detection electrode and the wire and a second deformation suppression layer along an outer peripheral part of the base material sheet are provided; a decoration sheet is provided through an adhesive layer on a side of the base material sheet where the detection electrode and the wire are provided; the wire is formed from the detection electrode to a connection terminal; the first deformation suppression layer is formed extending to a region closer to the connection terminal than a region on the base material sheet where the adhesive layer is provided, while covering a part of the wire other than the connection terminal; and an easily-deformable region where neither the first deformation suppression layer nor the second deformation suppression layer exists is formed between the first deformation suppression layer and the second deformation suppression layer on the base material sheet.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a capacitive touch sensor and a capacitive touch sensor module. [Background technology]

[0002] Capacitive touch sensors are widely used in various fields, such as in-vehicle electronic devices, to detect operation on operating surfaces. Flexible touch sensors are also known, which can be placed on curved or uneven surfaces and can be freely deformed. In flexible touch sensors, the application of stress can cause the base sheet to tear or break, or the wiring to break. This problem is particularly pronounced when a base sheet made of silicone rubber is combined with wiring made of a paste ink that does not contain silicone resin and is primarily composed of a metal filler. While thickening the base sheet and wiring can reduce breakage and improve electrical reliability, this method compromises flexibility.

[0003] Patent Documents 2 to 4 propose stretchable wiring boards that have a sheet-like stretchable base material, a stretchable wiring section, and a reinforcing region in a predetermined configuration, thereby alleviating local stress concentration and preventing disconnection of the wiring section. However, in such wiring boards, it is necessary to additionally arrange a reinforcing region, which complicates the manufacturing process and reduces design freedom. In addition, material limitations make the design of the entire wiring board very complicated, leading to increased production costs.

[0004] Patent Document 1 discloses a stretchable circuit board that includes a stretchable substrate, stretchable wiring, and a land portion in contact with the stretchable substrate, allowing electronic components to be mounted using conventional solder. However, capacitive sensors require a narrow, long, and complex wiring pattern that continues to the terminal portion used for ZIF connection or ACF connection. For this reason, it is difficult to apply a stretchable circuit board like that described in Patent Document 1 to a capacitive sensor, and localized stress concentration midway along the wiring remains an issue. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 045108 [Patent Document 2] Patent No. 6676373 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-162124 [Patent Document 4] Patent No. 6506653 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to provide a capacitive touch sensor that is easy to design and manufacture, and that can suppress peeling or breakage of electrodes and wiring even when made to conform to three-dimensional shapes such as curved or uneven surfaces, thereby suppressing a decrease in detection accuracy, and a capacitive touch sensor module equipped with the capacitive touch sensor. [Means for solving the problem]

[0007] The present invention includes the following aspects. [1] A decorative sheet comprising: a base sheet; a detection electrode provided on the base sheet for detecting a change in capacitance; wiring provided on the base sheet and electrically connected to the detection electrode; a first deformation suppressing layer covering the detection electrode and the wiring; a second deformation suppressing layer provided along the outer periphery of the base sheet; and a decorative sheet provided via an adhesive layer on the side of the base sheet on which the detection electrode and the wiring are provided, the wiring is formed from the detection electrode to a connection terminal provided on the base sheet, the first deformation suppressing layer covers a portion of the wiring other than the connection terminal, and is formed up to an area on the base sheet closer to the connection terminal than an area where the adhesive layer is provided, A capacitive touch sensor in which an easily deformable region where the first deformation suppressing layer and the second deformation suppressing layer are not present is formed between the first deformation suppressing layer and the second deformation suppressing layer on the base sheet. [2] The capacitive touch sensor according to [1], wherein the material constituting the first deformation suppression layer and the second deformation suppression layer includes at least one of a silicone resin and an ultraviolet-curable acrylic resin. [3] The capacitive touch sensor according to [1] or [2], wherein the material constituting the detection electrodes and the wiring is a silver paste ink that does not contain silicone resin. [4] The capacitive touch sensor according to any one of [1] to [3], wherein the material constituting the base sheet contains a silicone elastomer. [5] The capacitive touch sensor according to any one of [1] to [4], wherein the adhesive layer has a Young's modulus of 500 MPa or more and 2500 MPa or less as measured in accordance with JIS K7161:2014. [6] A capacitive touch sensor described in any one of [1] to [5], wherein, in a planar view from the decorative sheet side in the thickness direction of the base sheet, the first deformation suppression layer has a convex portion protruding from each of both sides of the wiring width direction at the end on the connection terminal side toward the connection terminal. [7] A capacitive touch sensor according to any one of [1] to [6], wherein at least one of the first deformation suppression layer and the second deformation suppression layer has a region formed in a comb-like shape when viewed in a plan view from the decorative sheet side in the thickness direction of the base sheet. [8] The capacitive touch sensor according to any one of [1] to [7], wherein the first deformation suppressing layer and the second deformation suppressing layer are formed independently of each other. [9] A capacitive touch sensor module including the capacitive touch sensor according to any one of [1] to [8]. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a capacitive touch sensor that is easy to design and manufacture, and that can suppress peeling or breakage of electrodes and wiring even when made to follow three-dimensional shapes such as curved surfaces or uneven surfaces, thereby suppressing a decrease in detection accuracy, and a capacitive touch sensor module equipped with the capacitive touch sensor. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a plan view illustrating an example of a capacitive touch sensor according to an embodiment; [Figure 2] 2 is a cross-sectional view of the electrostatic capacitance type touch sensor shown in FIG. 1 along the line AA. [Figure 3] 2 is a plan view of the capacitive touch sensor of FIG. 1, with the first deformation suppressing layer, the second deformation suppressing layer, the adhesive layer, and the decorative sheet omitted for convenience's sake. [Figure 4] 2 is a plan view of the capacitive touch sensor of FIG. 1, with the adhesive layer and decorative sheet omitted for convenience's sake. [Figure 5] FIG. 10 is a plan view showing a capacitive touch sensor according to another example of the embodiment, with the adhesive layer and the decorative sheet omitted for convenience. [Figure 6] FIG. 10 is a plan view showing a capacitive touch sensor according to another example of the embodiment, with the adhesive layer and the decorative sheet omitted for convenience. [Figure 7] FIG. 10 is a plan view showing a capacitive touch sensor according to another example of the embodiment, with the adhesive layer and the decorative sheet omitted for convenience. [Figure 8] FIG. 10 is a plan view showing a capacitive touch sensor according to another example of the embodiment, with the adhesive layer and the decorative sheet omitted for convenience. [Figure 9] FIG. 10 is a plan view showing a capacitive touch sensor according to another example of the embodiment, with the adhesive layer and the decorative sheet omitted for convenience. [Figure 10] FIG. 10 is a plan view showing a capacitive touch sensor according to another example of the embodiment, with the adhesive layer and the decorative sheet omitted for convenience. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Capacitive touch sensor] The following describes an example of a capacitive touch sensor of the present invention, with reference to the drawings. Note that the dimensions of the drawings shown in the following description are merely examples, and the present invention is not necessarily limited to these. Appropriate modifications can be made within the scope of the present invention.

[0011] Fig. 1 is a plan view of a capacitive touch sensor 1 according to an example of an embodiment, viewed from the decorative sheet side, Fig. 2 is a cross-sectional view of the capacitive touch sensor 1 taken along line AA in Fig. 1. Fig. 3 is a plan view showing the capacitive touch sensor of Fig. 1, in which the first deformation suppressing layer, the second deformation suppressing layer, the adhesive layer, and the decorative sheet are omitted for the sake of clarity in order to show the circuits (electrodes and wiring) on ​​the base sheet. Fig. 4 is a plan view showing the capacitive touch sensor of Fig. 1, in which the adhesive layer and the decorative sheet are omitted for the sake of clarity.

[0012] As shown in Figures 1 and 2, the capacitive touch sensor 1 of this example includes a base sheet 10, a detection electrode 20, wiring 22, a GND electrode 24, a first deformation suppression layer 30, a second deformation suppression layer 32, an adhesive layer 40, and a decorative sheet 50. In the capacitive touch sensor 1, detection electrodes 20, wiring 22, and GND electrodes 24 are provided in a predetermined pattern on a first surface 10a of a base sheet 10. A first deformation suppressing layer 30 is provided on the first surface 10a of the base sheet 10 so as to cover the detection electrodes 20 and wiring 22, and a second deformation suppressing layer 32 is provided along the outer periphery of the base sheet 10. Furthermore, a decorative sheet 50 is provided via an adhesive layer 40 on the side of the base sheet 10 where the detection electrodes 20 and wiring 22 are provided.

[0013] As shown in Figure 3, the base sheet 10 in this example has a main body portion 12 that is rectangular in plan view, and a strip-shaped portion 14 that extends so as to protrude from a portion of one of the short sides of the main body portion 12, and a connection terminal 16 is formed at the tip portion of the strip-shaped portion 14. The planar shape of the base sheet 10 is not limited to the shape in this example, and can be set appropriately depending on the application.

[0014] The base sheet 10 may be any flexible sheet, such as a resin sheet, and is preferably a transparent insulating resin sheet. The term "insulating" means that the electrical resistance is 1 MΩ or more, preferably 10 MΩ or more. The term "transparent" means that the light transmittance measured according to JIS K7136 is 50% or more.

[0015] The material constituting the base sheet 10 can be, for example, an elastomer such as a silicone elastomer, and silicone elastomer is preferred because it is flexible and has excellent conformability to three-dimensional shapes. The material constituting the base sheet 10 may be one type or two or more types.

[0016] The Shore A hardness of the elastomer constituting the base sheet 10 is preferably 10 or more, more preferably 20 or more. If the Shore A hardness is equal to or greater than the lower limit, peeling or breakage of the detection electrodes 20 and wiring 22 can be easily prevented. The Shore A hardness of the elastomer is preferably 60 or less, more preferably 30 or less. If the Shore A hardness is equal to or less than the upper limit, the capacitance touch sensor 1 can easily be made to conform to the three-dimensional shape. The preferred lower and upper limits of the Shore A hardness of the elastomer can be combined in any desired manner. The Shore A hardness is a type A durometer hardness measured according to JIS K 6253 with a test piece having a thickness (height) of 1 cm.

[0017] The thickness of the base sheet 10 is preferably 12 μm or more, and more preferably 30 μm or more. If the thickness of the base sheet 10 is equal to or greater than the above-mentioned lower limit, peeling or disconnection of the detection electrodes 20 and wiring 22 can be easily prevented. The thickness of the base sheet 10 is preferably 250 μm or less, and more preferably 100 μm or less. If the thickness of the base sheet 10 is equal to or less than the above-mentioned upper limit, the capacitance touch sensor 1 can easily be made to conform to the three-dimensional shape. The preferred lower and upper limits of the thickness of the base sheet 10 can be combined as desired.

[0018] The breaking elongation of the base sheet 10 is preferably 100% or more, and more preferably 500% or more. If the breaking elongation of the base sheet 10 is equal to or greater than the lower limit, the base sheet 10 is likely to be able to conform to the three-dimensional shape of the capacitive touch sensor 1. The breaking elongation of the base sheet 10 is preferably 1000% or less, and more preferably 800% or less. If the breaking elongation of the base sheet 10 is equal to or less than the upper limit, peeling or breakage of the detection electrodes 20 and wiring 22 due to excessive elongation is likely to be suppressed. The preferable lower and upper limits of the breaking elongation of the base sheet 10 can be combined as desired. The breaking elongation is measured in accordance with JIS K 6251:2017 using a dumbbell No. 2 test piece at a tensile speed of 500 mm / min.

[0019] The tensile strength of the base sheet 10 is preferably 4 MPa or more, more preferably 5 MPa or more. If the tensile strength of the base sheet 10 is equal to or greater than the lower limit, peeling and breakage of the detection electrodes 20 and wiring 22 can be easily prevented. The tensile strength of the base sheet 10 is preferably 12 MPa or less, more preferably 9 MPa or less. If the tensile strength of the base sheet 10 is equal to or less than the upper limit, the capacitance touch sensor 1 can easily be made to conform to the three-dimensional shape. The preferred lower and upper limits of the tensile strength of the base sheet 10 can be combined in any manner. The tensile strength is measured in accordance with JIS K 6251:2017 using a dumbbell No. 2 test piece at a tension speed of 500 mm / min.

[0020] 2 and 3, in this example, three detection electrodes 20 are provided on the first surface 10a of the main body 12 of the base sheet 10 at the center of the short side direction of the main body 12, spaced apart along the long side direction. Wiring 22 is electrically connected to each detection electrode 20, and the wiring 22 extends to a connection terminal 16. The connection terminal 16 can be electrically connected to a capacitance detection unit of, for example, a circuit board (rigid board). This allows the capacitive touch sensor 1 to detect a conductor coming into contact with or approaching a detection electrode 20 from a change in the capacitance of the detection electrode 20. The number of detection electrodes 20 is not limited to three and can be set appropriately, and may be two or less, or may be four or more.

[0021] The detection electrode 20 is an electrode for detecting contact or proximity of a conductor by detecting a change in capacitance. The detection of the change in capacitance by the detection electrode 20 may be a self-capacitance type or a mutual capacitance type. The detection electrode 20 may be in the form of, for example, a solid electrode, a comb-tooth electrode, a mesh electrode, a checkered electrode pattern, a diamond pattern, or the like. The planar shape of the detection electrode 20 is rectangular in the examples shown in FIGS. 1 and 3, but may be circular, elliptical, or the like.

[0022] An example of a material that constitutes the detection electrode 20 is a paste ink that does not contain silicone resin and is primarily composed of a metal filler. However, "primarily composed of a metal filler" means that the proportion of the metal filler relative to the total mass of the conductive material in the paste ink is 60% by mass or more. Examples of the metal filler include silver filler, copper filler, and gold filler, with silver filler being preferred.

[0023] The paste ink constituting the detection electrode 20 may contain other conductive materials such as conductive polymers (polythiophene-based conductive polymers (PEDOT / PSS), indium-doped tin oxide (ITO), etc.), conductive nanowires (silver nanowires, gold nanowires, etc.), conductive metal oxide particles (ITO particles, etc.), etc. The material for forming the detection electrode 20 is preferably a silver paste ink that does not contain silicone resin, and particularly preferably a silver paste ink in which a silver filler is added to an acrylic resin.

[0024] The thickness of the detection electrode 20 is preferably 1 μm or more, and more preferably 5 μm or more. If the thickness of the detection electrode 20 is equal to or greater than the above-mentioned lower limit, peeling or breakage of the detection electrode 20 is easily suppressed. The thickness of the detection electrode 20 is preferably 20 μm or less, and more preferably 15 μm or less. If the thickness of the detection electrode 20 is equal to or less than the above-mentioned upper limit, it is easy to make the capacitive touch sensor 1 thinner. The preferred lower and upper limits of the thickness of the detection electrode 20 can be combined arbitrarily.

[0025] The material of the wiring 22 is not particularly limited, and examples thereof include the same material as that of the detection electrode 20. Silver paste ink that does not contain silicone resin is preferred, and silver paste ink in which silver filler is added to acrylic resin is particularly preferred.

[0026] The thickness of the wiring 22 can be, for example, approximately the same as the thickness of the detection electrode 20, and is preferably 1 μm or more, more preferably 5 μm or more, and is preferably 20 μm or less, more preferably 15 μm or less. The preferable lower and upper limits of the thickness of the wiring 22 can be combined arbitrarily.

[0027] The line width of the wiring 22 is preferably 30 μm or more, more preferably 50 μm or more, because this makes it easier to prevent peeling or breakage of the wiring 22. The line width of the wiring 22 is preferably 1000 μm or less, more preferably 500 μm or less, because this ensures freedom in design. The preferred lower and upper limits of the line width of the wiring 22 can be combined arbitrarily.

[0028] The aspect ratio (thickness / line width) of the thickness to line width of the wiring 22 is preferably 1 / 100 or more, more preferably 1 / 50 or more, and is preferably 1 / 5 or less, more preferably 1 / 10 or less.

[0029] The GND electrode 24 is a grounded electrode. By providing the GND electrode 24, noise generated when a conductor is brought close to the detection electrode 20 or the wiring 22 is reduced, thereby improving the detection accuracy of the capacitive touch sensor 1. 1 and 3, the GND electrode 24 is disposed so as to surround each of the detection electrodes 20 and the wiring 22, and forms a rectangular solid electrode in the region between each of the detection electrodes 20. The wiring 22 is also electrically connected to the GND electrode 24, and the wiring 22 is formed up to the connection terminal 16. The pattern of the GND electrode 24 is not limited to this pattern, and can be designed appropriately according to the circuit patterns of the detection electrodes 20 and the wiring 22.

[0030] The material of the GND electrode 24 is not particularly limited, and can be, for example, the same as the material of the detection electrode 20. Silver paste ink that does not contain silicone resin is preferred, and silver paste ink in which silver filler is added to acrylic resin is particularly preferred. The thickness of the GND electrode 24 can be, for example, approximately the same as the thickness of the detection electrode 20, and is preferably 1 μm or more, more preferably 5 μm or more, and is preferably 20 μm or less, more preferably 15 μm or less. The preferable lower and upper limits of the thickness of the GND electrode 24 can be combined arbitrarily.

[0031] 4, the first deformation suppression layer 30 is provided on the first surface 10a of the base sheet 10 along the patterns of the detection electrodes 20 and the wiring 22 so as to cover the detection electrodes 20 and the wiring 22. By providing the first deformation suppression layer 30 so as to cover the detection electrodes 20 and the wiring 22, stress concentration at the portions of the base sheet 10 where the detection electrodes 20 and the wiring 22 are provided is suppressed, thereby suppressing local deformation, and thus peeling and disconnection of the detection electrodes 20 and the wiring 22.

[0032] Each detection electrode 20 is entirely covered with a first deformation suppression layer 30, but if the detection electrode 20 is a mesh electrode, the first deformation suppression layer 30 may be provided along the mesh electrode portion, and the first deformation suppression layer 30 may not be present in the portion where there is no mesh electrode. The wiring 22 is entirely covered with the first deformation suppression layer 30 except for the vicinity of the connection terminal 16 .

[0033] The distance (offset amount) from the outer edge of the detection electrode 20 and the wiring 22 covered by the first deformation suppressing layer 30 to the outer edge of the first deformation suppressing layer 30 covering them is preferably 0.10 mm or more, more preferably 0.15 mm or more. If the offset amount is equal to or greater than the lower limit, the effect of the first deformation suppressing layer 30 in suppressing peeling or breakage of the detection electrode 20 and the wiring 22 is easily obtained. The offset amount is preferably equal to or less than 0.30 mm, more preferably equal to or less than 0.25 mm. If the offset amount is equal to or less than the upper limit, a sufficient deformation-prone region can be secured. The preferable lower and upper limits of the offset amount can be combined as desired.

[0034] 2, in the band-shaped portion 14 of the base sheet 10, the first deformation suppressing layer 30 covers the portions of each wiring 22 other than the connection terminals 16, and is formed up to an area closer to the connection terminals 16 than the area on the base sheet 10 where the adhesive layer 40 is provided. The area of ​​the base sheet 10 near the connection terminals 16 that is not bonded to the decorative sheet 50 via the adhesive layer 40 tends to be more flexible and more easily deformed than the area bonded to the decorative sheet 50. However, by providing the first deformation suppressing layer 30 up to the area near the connection terminals 16 where the adhesive layer 40 is not present, local deformation near the connection terminals 16 is suppressed, and peeling and disconnection of the wiring 22 are sufficiently suppressed.

[0035] 4, in a plan view of the base sheet 10 from the decorative sheet 50 side in the thickness direction, the first deformation suppressing layer 30 preferably has protrusions 31, 31 protruding from both sides in the width direction of each wire 22 at the end on the connection terminal 16 side toward the connection terminal 16. This makes it less likely that deformation that bends the wires 22 will occur near the connection terminal 16 of the base sheet 10, making it even less likely that peeling or breakage of the wires 22 will occur near the connection terminal 16.

[0036] The thickness of the first deformation suppressing layer 30 is preferably 10 μm or more, more preferably 12 μm or more. If the thickness of the first deformation suppressing layer 30 is equal to or greater than the above-mentioned lower limit, peeling or breakage of the detection electrodes 20 and wiring 22 can be easily suppressed. The thickness of the first deformation suppressing layer 30 is preferably 20 μm or less, more preferably 16 μm or less. If the thickness of the first deformation suppressing layer 30 is equal to or less than the above-mentioned upper limit, it is easy to obtain the ability to conform to the three-dimensional shape of the capacitive touch sensor 1. The preferred lower and upper limits of the thickness of the first deformation suppressing layer 30 can be combined arbitrarily.

[0037] 4, the second deformation suppression layer 32 is provided on the first surface 10a of the base sheet 10 along the entire outer periphery of the base sheet 10. This prevents the capacitive touch sensor 1 from being torn apart from the outer edge. The width of the second deformation suppressing layer 32 is preferably 0.1 mm or more, more preferably 0.3 mm or more, so that the capacitive touch sensor 1 is less likely to be torn from its outer edge. The width of the second deformation suppressing layer 32 is preferably 2 mm or less, more preferably 1 mm or less, so that a sufficient deformation-prone region can be secured. The preferred lower and upper limits of the width of the second deformation suppressing layer 32 can be arbitrarily combined.

[0038] For the same reasons as for the thickness of the first deformation suppressing layer 30, the thickness of the second deformation suppressing layer 32 is preferably 10 μm or more, more preferably 12 μm or more, and is preferably 20 μm or less, more preferably 16 μm or less. The preferred lower and upper limits for the thickness of the second deformation suppressing layer 32 can be combined arbitrarily. The thickness of the first deformation suppressing layer 30 and the thickness of the second deformation suppressing layer 32 may be the same or different.

[0039] The material constituting the first deformation suppression layer 30 and the second deformation suppression layer 32 may be any material capable of suppressing deformation of the portions of the base sheet 10 where the first deformation suppression layer 30 and the second deformation suppression layer 32 are provided, and examples thereof include silicone resin and ultraviolet-curable acrylic resin. The material constituting the first deformation suppression layer 30 and the second deformation suppression layer 32 preferably contains at least one of silicone resin and ultraviolet-curable acrylic resin.

[0040] The Shore D hardness of the material constituting the first deformation suppression layer 30 and the second deformation suppression layer 32 is preferably 60 or more, more preferably 65 or more, since this easily prevents peeling or breakage of the detection electrodes 20 and the wiring 22. Furthermore, the Shore D hardness of the material is preferably 75 or less, since this easily allows the material to conform to the three-dimensional shape of the capacitive touch sensor 1. The preferred lower and upper limits of the Shore D hardness of the material can be arbitrarily combined. The Shore D hardness of the material constituting the first deformation suppression layer 30 and the second deformation suppression layer 32 may be the same or different. The Shore D hardness is a type D durometer hardness measured according to JIS K 6253 with a test piece having a thickness (height) of 1 cm.

[0041] The flexural modulus of the first deformation suppression layer 30 and the second deformation suppression layer 32 is preferably 500 MPa or more, more preferably 1500 MPa or more, because this easily prevents peeling or breakage of the detection electrodes 20 and the wiring 22. The flexural modulus of the first deformation suppression layer 30 and the second deformation suppression layer 32 is preferably 2500 MPa or less, because this easily allows the capacitance touch sensor 1 to conform to the three-dimensional shape. The preferred lower and upper limits of the flexural modulus of the first deformation suppression layer 30 and the second deformation suppression layer 32 can be arbitrarily combined. The flexural modulus of the first deformation suppression layer 30 and the second deformation suppression layer 32 may be the same or different. The flexural modulus is measured in accordance with JIS K 7171.

[0042] As shown in FIG. 4 , in the capacitive touch sensor 1, an easily deformable region 60, where the first deformation suppressing layer 30 and the second deformation suppressing layer 32 are not present, is formed between the first deformation suppressing layer 30 and the second deformation suppressing layer 32. That is, the easily deformable region 60, where the first deformation suppressing layer 30 and the second deformation suppressing layer 32 are not present, is formed between the portion of the base sheet 10 where the detection electrodes 20 and the wiring 22 are provided and the outer periphery. By providing such an easily deformable region 60, when stress is applied to the capacitive touch sensor 1, the stress is absorbed by the easily deformable region 60. This prevents stress from concentrating in the region where the first deformation suppressing layer 30 and the second deformation suppressing layer 32 are present, i.e., the portion of the base sheet 10 where the detection electrodes 20 and the wiring 22 are provided and the outer periphery, and causing local deformation. As a result, the detection electrodes 20 and the wiring 22 are not peeled off from the base sheet 10, which would result in an increase in resistance, the detection electrodes 20 and the wiring 22 being disconnected, and the capacitive touch sensor 1 is not torn from the outer periphery.

[0043] The easily deformable region 60 of the base sheet 10 may be provided with a GND electrode as in this example. The first deformation suppression layer 30 and the second deformation suppression layer 32 may be partially connected, but since the effect of the easily deformable region 60 can be more easily obtained, it is preferable that the first deformation suppression layer 30 and the second deformation suppression layer 32 are formed independently, as in this example.

[0044] Examples of materials constituting the adhesive layer 40 include known curing adhesives (liquid adhesives before bonding) or pressure-sensitive adhesives (gel-like pressure-sensitive adhesives before bonding). Examples of adhesives and pressure-sensitive adhesives include acrylic resins, urethane resins, and ethylene-vinyl acetate copolymers. The curing adhesive may be a solvent type containing a solvent that volatilizes upon curing, or a hot-melt type.

[0045] The Young's modulus of the adhesive layer 40 is preferably 500 MPa or more, and more preferably 1500 MPa or more, because this easily prevents peeling or disconnection of the detection electrodes 20 and the wiring 22. The Young's modulus of the adhesive layer 40 is preferably 2500 MPa or less, and more preferably 2000 MPa or less, because this easily allows the adhesive layer 40 to conform to the three-dimensional shape of the capacitive touch sensor 1. The preferable lower and upper limits of the Young's modulus of the adhesive layer 40 can be combined arbitrarily. The Young's modulus of the adhesive layer 40 is measured in accordance with JIS K7161:2014.

[0046] The average thickness of the adhesive layer 40 is preferably 10 μm or more, and more preferably 12 μm or more, because this easily prevents peeling or disconnection of the detection electrodes 20 and the wiring 22. The average thickness of the adhesive layer 40 is preferably 20 μm or less, and more preferably 16 μm or less, because this easily allows the adhesive layer 40 to conform to the three-dimensional shape of the capacitive touch sensor 1. The preferred lower and upper limits of the average thickness of the adhesive layer 40 can be combined arbitrarily.

[0047] The decorative sheet 50 may be any flexible and decorated sheet, such as a decorated resin sheet. Examples of materials that can be used to form the decorative sheet 50 include silicone elastomer and thermoplastic polyurethane (TPU). The decoration of the decorative sheet 50 is not particularly limited, and any decoration can be used depending on the application, such as a combination of ornaments, letters, figures, symbols, patterns, etc., or a combination of these with colors.

[0048] The thickness of the decorative sheet 50 is preferably 25 μm or more, and more preferably 100 μm or more, because this helps to prevent peeling or disconnection of the detection electrodes 20 and the wiring 22. The thickness of the decorative sheet 50 is preferably 5000 μm or less, and more preferably 1000 μm or less, because this helps to ensure conformability to the three-dimensional shape of the capacitive touch sensor 1. The preferred lower and upper limits of the thickness of the decorative sheet 50 can be combined arbitrarily.

[0049] The method for manufacturing the capacitive touch sensor 1 is not particularly limited. For example, the base sheet 10 and the decorative sheet 50 can be produced using known molding methods such as press molding, extrusion molding, and calendar molding. Furthermore, the detection electrodes 20, the wiring 22, the GND electrodes 24, the first deformation suppression layer 30, the second deformation suppression layer 32, and the adhesive layer 40 can be formed in a predetermined pattern in this order on the base sheet 10 by screen printing. When the detection electrodes 20, the wiring 22, and the GND electrodes 24 are formed by screen printing, an optical surface treatment or application of an easy-adhesion coating (primer) may be performed on the first surface 10a of the base sheet 10 as a pre-processing step before the screen printing to improve the adhesion of the detection electrodes 20, the wiring 22, and the GND electrodes 24 to the base sheet 10.

[0050] As described above, the capacitive touch sensor 1 is provided with the first deformation suppressing layer 30 that protects the detection electrodes 20 and the wiring 22, and the second deformation suppressing layer 32 that protects the outer periphery of the base sheet 10, and a stress-absorbing region 60 is formed between the first deformation suppressing layer 30 and the second deformation suppressing layer 32. This makes it difficult for the portions where the detection electrodes 20 and the wiring 22 are provided and the outer periphery to deform locally, even when stress is applied to the capacitive touch sensor 1. As a result, it is possible to sufficiently prevent the detection electrodes 20 and the wiring 22 from peeling off from the base sheet 10, resulting in an increase in resistance, the detection electrodes 20 and the wiring 22 from breaking, and the capacitive touch sensor 1 from being torn apart from the outer periphery. Furthermore, in the vicinity of the connection terminal 16, the first deformation suppression layer 30 is formed up to an area closer to the connection terminal 16 than the adhesive layer 40, thereby suppressing local deformation in the vicinity of the connection terminal 16. Therefore, peeling and breakage of the wiring 22 are sufficiently suppressed even in the vicinity of the connection terminal 16.

[0051] [Capacitive touch sensor module] The capacitive touch sensor module of the present invention is a module equipped with the capacitive touch sensor of the present invention, and can adopt any known configuration other than the inclusion of the capacitive touch sensor of the present invention. For example, a capacitive touch sensor module in which the capacitive touch sensor of the present invention is attached to an object having a three-dimensional shape such as a curved surface or an uneven surface can be exemplified. Examples of objects to which a capacitive touch sensor can be attached include soft objects and wearable devices that can be attached to the human body and are capable of sensing contact, pressure, biosignals, and the like.

[0052] The present invention is not limited to the above-described embodiment. For example, as shown in Figures 5 to 7, the capacitive touch sensor of the present invention may have, in plan view, an area in which the first deformation suppressing layer 30 is formed in a comb-like shape between each of the detection electrodes 20 on the base sheet 10. For convenience, the adhesive layer and the decorative sheet are omitted from Figures 5 to 7. By providing the first deformation suppressing layer in a comb-like shape in this way, the direction in which stress is easily absorbed in the easy-deformation area where the first deformation suppressing layer and the second deformation suppressing layer are not present may be controlled. Furthermore, the area where the first deformation suppressing layer is formed in a comb-teeth shape is not limited to the area between the detection electrodes.

[0053] As shown in Fig. 8, the capacitive touch sensor of the present invention may have, in a plan view, an area in which the first deformation suppressing layer 30 and the second deformation suppressing layer 32 are formed in a comb-like shape between each detection electrode 20 of the base sheet 10. For convenience, the adhesive layer and the decorative sheet are omitted from Fig. 8. By providing the first deformation suppressing layer and the second deformation suppressing layer in a comb-like shape in this way, the direction in which stress is easily absorbed in the easy-deformation area where the first deformation suppressing layer and the second deformation suppressing layer are not present may be controlled. Furthermore, the area where the first and second deformation suppressing layers are formed in a comb-teeth shape is not limited to the area between the detection electrodes.

[0054] As shown in Fig. 9, the first deformation suppressing layer 30 and the second deformation suppressing layer 32 may be partially connected in the vicinity of the connection terminal 16 of the strip portion 14 of the base sheet 10. Furthermore, as shown in Fig. 10, the second deformation suppressing layer 32 may not be provided at the end of the strip portion 14 of the base sheet 10 on the connection terminal 16 side. For convenience, the adhesive layer and decorative sheet are omitted from Figs. 9 and 10.

[0055] The capacitive touch sensor of the present invention may not have a GND electrode. In addition, within the scope of the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate. [Explanation of symbols]

[0056] 1...Capacitive touch sensor 10...Base sheet 16...Connection terminal 20...Detection electrode 22...Wiring 24...GND electrode 30...First deformation suppression layer 31...Convex part 32...Second deformation suppression layer 40...adhesive layer 50...Decorative sheet 60...Easy deformation area

Claims

1. a base sheet; a detection electrode provided on the base sheet for detecting a change in capacitance; wiring provided on the base sheet and electrically connected to the detection electrode; a first deformation suppressing layer covering the detection electrode and the wiring; a second deformation suppressing layer provided along the outer periphery of the base sheet; and a decorative sheet provided via an adhesive layer on the side of the base sheet on which the detection electrode and the wiring are provided, the wiring is formed from the detection electrode to a connection terminal provided on the base sheet, the first deformation suppressing layer covers a portion of the wiring other than the connection terminal, and is formed up to an area on the base sheet closer to the connection terminal than an area where the adhesive layer is provided, A capacitive touch sensor in which an easily deformable region where the first deformation suppressing layer and the second deformation suppressing layer are not present is formed between the first deformation suppressing layer and the second deformation suppressing layer in the base sheet.

2. The capacitive touch sensor according to claim 1 , wherein the material constituting the first deformation suppressing layer and the second deformation suppressing layer includes at least one of a silicone resin and an ultraviolet-curable acrylic resin.

3. The capacitive touch sensor according to claim 1 , wherein the material constituting the detection electrodes and the wiring is a silver paste ink that does not contain a silicone resin.

4. The capacitive touch sensor according to claim 1 , wherein the material constituting the base sheet includes a silicone elastomer.

5. 2. The capacitive touch sensor according to claim 1, wherein the adhesive layer has a Young's modulus measured in accordance with JIS K7161:2014 of 500 MPa or more and 2500 MPa or less.

6. 2. The capacitive touch sensor of claim 1, wherein, in a planar view from the decorative sheet side in the thickness direction of the base sheet, the first deformation suppression layer has a convex portion protruding from each of both sides of the width direction of the wiring at the end on the connection terminal side toward the connection terminal.

7. 2. The capacitive touch sensor according to claim 1, wherein, in a planar view from the decorative sheet side in the thickness direction of the base sheet, at least one of the first deformation suppression layer and the second deformation suppression layer has a region formed in a comb-tooth shape.

8. The capacitive touch sensor according to claim 1 , wherein the first deformation suppressing layer and the second deformation suppressing layer are formed independently of each other.

9. A capacitive touch sensor module comprising the capacitive touch sensor according to any one of claims 1 to 8.

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