Sensor sheet and manufacturing method for the same

Abstract

To provide a sensor sheet excellent in followability to a three-dimensional curved surface structure and its manufacturing method.SOLUTION: A sensor sheet 1 includes: a base material 11; a transparent conductive layer 12 arranged on at least one principal surface 11a; an auxiliary electrode layer 13 covering at least a part of a periphery of the transparent conductive layer 12; a first transparent insulation layer 14 which is arranged on the transparent conductive layer 12 and the auxiliary electrode layer 13 and covers the transparent conductive layer 12 and the auxiliary electrode layer 13; and an adhesion layer 15 disposed on another surface 11b of the base material 11. An arithmetic average roughness (Ra) of the at least one principal surface 11a of the base material 11 is 0.5 μm or more and 1.5 μm or less. The transparent conductive layer 12 is formed of conductive ink containing PEDOT-PSS. A thickness of the transparent conductive layer 12 is 1 μm or smaller, which is larger than a 10 point average roughness (Rz) of the at least one principal surface 11a of the base material 11, a refractive index difference between the base material 11 and the transparent conductive layer 12 is 0.2 or less, and the auxiliary electrode layer 13 is formed of opaque metallic paste ink.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sensor sheet and a manufacturing method thereof. [Background technology]

[0002] Sensors and heaters are known in which electrodes having a fine wire mesh structure made of a transparent conductive material or a non-transparent conductive material are formed on a transparent substrate such as polyethylene terephthalate (PET) by a screen printing method (see, for example, Patent Documents 1 to 4).

[0003] On the other hand, there is a demand for a housing with high design quality, and a sensor or heater module that can follow three-dimensional curved structures such as the surface of a living body or a robot, etc. However, when the conventional technology is applied, there is a limit to the flexibility due to the rigidity of the base material of the sensor or heater module, and the sensor or heater module cannot sufficiently follow the three-dimensional curved structure.

[0004] Sensors and heaters are known in which electrodes with a fine wire mesh structure made of a transparent conductive material or a non-transparent conductive material are formed by a screen printing method on a transparent substrate made of polyethylene terephthalate (PET) or the like (see, for example, Patent Documents 1 to 4). On the other hand, there is a demand for sensor modules and heater modules (hereinafter, sensor modules and heater modules may be collectively referred to as "modules") that can follow the three-dimensional curved structures of housings that require high design quality and the surfaces of living organisms and robots. However, when conventional technology is applied to such modules, there is a limit to the flexibility due to the rigidity of the substrate that constitutes the module.

[0005] When a transparent elastomer is used as the base material to impart flexibility to the module, the following problems arise. Due to differences in hardness and elasticity between the substrate and the conductive material used in the electrodes, the interfacial adhesion of the module decreases when stress is applied. During screen printing, the substrate adheres to the plate, and the plate release mechanism does not function as intended, resulting in poor printability on the substrate and poor film quality.

[0006] Although structures for imparting resistance to stretching to electrodes and methods for manufacturing electrodes are known, there are problems with the layer structure and complicated processes, which reduce transparency. In addition, the performance required for electrodes is merely conformability to curved surfaces, and in cases where repeated stretching of several tens of percent or more is not required, these are excessive quality (see, for example, Patent Document 5). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2014-093253 A [Patent Document 2] JP 2016-157510 A [Patent Document 3] JP 2016-126913 A [Patent Document 4] Patent Publication No. 2022-074709 [Patent Document 5] Patent Publication No. 2021-109371 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above circumstances, and has an object to provide a sensor sheet that is excellent in conformity to three-dimensional curved structures, and a manufacturing method thereof. [Means for solving the problem]

[0009] The present invention has the following aspects. [1] A substrate made of a transparent elastomer; A transparent conductive layer disposed on at least one of the main surfaces of the substrate; an auxiliary electrode layer disposed on the transparent conductive layer so as to cover at least a portion of a periphery of the transparent conductive layer; a first transparent insulating layer disposed on the transparent conductive layer and the auxiliary electrode layer, the first transparent insulating layer covering the transparent conductive layer and the auxiliary electrode layer in a plan view of the base material; an adhesive layer disposed on a surface of the base opposite to a surface on which the transparent conductive layer is disposed, The arithmetic average roughness (Ra) of at least one main surface of the substrate is 0.5 μm or more and 1.5 μm or less, the transparent conductive layer is formed of a conductive ink containing PEDOT-PSS; the transparent conductive layer has a thickness greater than the ten-point average roughness (Rz) of at least one of the main surfaces of the substrate and less than or equal to 1 μm; a refractive index difference between the substrate and the transparent conductive layer is 0.2 or less; The auxiliary electrode layer is formed by a non-transparent metal paste ink. [2] Further comprising a second transparent insulating layer disposed between the base material and the transparent conductive layer and covering the transparent conductive layer in a plan view of the base material; The sensor sheet according to [1], wherein a thickness of the second transparent insulating layer is greater than a ten-point average roughness (Rz) of at least one of the main surfaces of the base material. [3] Further comprising a third transparent insulating layer disposed between the base material and the adhesive layer and covering the transparent conductive layer and the auxiliary electrode layer in a plan view of the base material; The sensor sheet according to [1] or [2], wherein a thickness of the third transparent insulating layer is greater than a ten-point average roughness (Rz) of at least one of the main surfaces of the base material. [4] The sensor sheet described in [3], further comprising a design layer disposed between the third transparent insulating layer and the adhesive layer. [5] A transparent conductive layer forming step of forming a transparent conductive layer on at least one main surface of a substrate made of a transparent elastomer by mesh screen printing or metal plate printing using a conductive ink containing PEDOT-PSS; an auxiliary electrode layer forming step of forming an auxiliary electrode layer on the transparent conductive layer using a non-transparent metal paste ink so as to cover at least a portion of a periphery of the transparent conductive layer; a first transparent insulating layer forming step of forming a first transparent insulating layer on the transparent conductive layer and the auxiliary electrode layer using a first transparent insulating material, the first transparent insulating layer covering the transparent conductive layer and the auxiliary electrode layer in a plan view of the base material; and forming an adhesive layer on a surface of the base opposite to a surface on which the transparent conductive layer is disposed, using an adhesive. In the transparent conductive layer forming step, the mesh number of a screen printing plate used in mesh screen printing is 80 or more and 600 or less, In the transparent conductive layer forming step, the thickness of the metal printing plate used in the metal printing is 5 μm or less, A method for manufacturing a sensor sheet, wherein in the transparent conductive layer forming step, after printing the conductive ink, a plate separation is performed by peeling the screen printing plate or the metal printing plate from the substrate. [6] The method for manufacturing a sensor sheet described in [5], further comprising, prior to the transparent conductive layer forming step, a second transparent insulating layer forming step of forming a second transparent insulating layer between the substrate and the transparent conductive layer, the second transparent insulating layer covering the transparent conductive layer in a planar view of the substrate. [7] The method for manufacturing a sensor sheet described in [5] or [6], further comprising, before the adhesive layer forming step, a third transparent insulating layer forming step of forming a third transparent insulating layer on the surface of the substrate opposite to the surface on which the transparent conductive layer is arranged, the third transparent insulating layer covering the transparent conductive layer and the auxiliary electrode layer in a planar view of the substrate. [8] A method for manufacturing a sensor sheet as described in [7], further comprising, prior to the adhesive layer forming step, a design layer forming step of forming a design layer between the third transparent insulating layer and the adhesive layer. Effect of the Invention

[0010] According to the present invention, it is possible to provide a sensor sheet that is excellent in conformity with a three-dimensional curved structure and a manufacturing method thereof. [Brief description of the drawings]

[0011] [Figure 1]1A and 1B are schematic diagrams showing a first embodiment of a sensor sheet according to the present invention, where (a) is a plan view, (b) is a cross-sectional view taken along line AA in (a), and (c) is a back view. [Diagram 2] 5A to 5C are schematic diagrams showing a second embodiment of a sensor sheet according to the present invention, where (a) is a plan view, (b) is a cross-sectional view taken along line BB in (a), and (c) is a back view. [Diagram 3] 5A to 5C are schematic diagrams showing a third embodiment of a sensor sheet according to the present invention, where (a) is a plan view, (b) is a cross-sectional view taken along line CC in (a), and (c) is a back view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] BEST MODE FOR CARRYING OUT THE DISCLOSURE Hereinafter, an embodiment of a sensor sheet according to the present invention will be described in detail with reference to Figs. In addition, in each drawing used in the following description, for the sake of convenience, characteristic parts may be shown enlarged in order to make the features easier to understand, and the dimensional ratios may differ from the actual ones. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and may be appropriately changed and implemented within the scope that does not change the gist of the present invention.

[0013] <Sensor sheet> The sensor sheet of the present invention comprises a substrate made of a transparent elastomer, a transparent conductive layer arranged on at least one main surface of the substrate, an auxiliary electrode layer arranged on the transparent conductive layer so as to cover at least a portion of the periphery of the transparent conductive layer, a first transparent insulating layer arranged on the transparent conductive layer and on the auxiliary electrode layer and covering the transparent conductive layer and the auxiliary electrode layer in a planar view of the substrate, and an adhesive layer arranged on the surface of the substrate opposite to the surface on which the transparent conductive layer is arranged. Hereinafter, first to third embodiments of the sensor sheet of the present invention will be described in detail in order.

[0014] [First embodiment] FIG. 1 is a schematic diagram showing a first embodiment of a sensor sheet according to the present invention, where (a) is a plan view, (b) is a cross-sectional view taken along line AA in (a), and (c) is a back view. As shown in FIG. 1, the sensor sheet 1 of this embodiment includes a substrate 11, a transparent conductive layer 12, an auxiliary electrode layer 13, a first transparent insulating layer 14, and an adhesive layer 15. 1, the substrate 11 has a convex shape in a plan view. The substrate 11 has a base 11A having a rectangular shape in a plan view, and a protrusion 11B having a rectangular shape in a plan view that extends from the center of the short side of the base 11A in the direction of the long side of the base 11A. The transparent conductive layer 12 is disposed on one main surface 11a of the substrate 11. Furthermore, the transparent conductive layer 12 has a rectangular shape when the substrate 11 is viewed from above.

[0015] The auxiliary electrode layer 13 is disposed on the transparent conductive layer 12 and on one of the main surfaces 11a of the substrate 11 so as to cover a part of the periphery of the transparent conductive layer 12. As a result, the auxiliary electrode layer 13 is electrically connected to the transparent conductive layer 12. The auxiliary electrode layer 13 is composed of two auxiliary electrode layers 13A and 13B disposed apart from each other. The auxiliary electrode layers 13A and 13B each have a part (hereinafter referred to as a "connection part") 13a, 13b covering a part of the periphery of the transparent conductive layer 12, each of which has a square shape in a plan view of the substrate 11. The connection part 13a of the auxiliary electrode layer 13A and the connection part 13b of the auxiliary electrode layer 13B are disposed almost diagonally on the rectangular transparent conductive layer 12. The auxiliary electrode layer 13A has a conductive part 13c extending from the connection part 13a to the protrusion 11B along the periphery of the substrate 11. Auxiliary electrode layer 13B has conductive portion 13d extending from connection portion 13b to protrusion 11B along the periphery of substrate 11. Conductive portion 13c and conductive portion 13d are disposed parallel to and spaced apart from each other on protrusion 11B.

[0016] The first transparent insulating layer 14 is disposed on the transparent conductive layer 12 and the auxiliary electrode layer 13. The first transparent insulating layer 14 covers the transparent conductive layer 12 and the auxiliary electrode layer 13 in a plan view of the base material 11. The first transparent insulating layer 14 is not disposed in an area of ​​one main surface 11a of the base material 11 where the transparent conductive layer 12 and the auxiliary electrode layer 13 are not disposed.

[0017] The adhesive layer 15 is disposed on the surface (other main surface) 11b of the substrate 11 opposite to the surface on which the transparent conductive layer 12 is disposed. The adhesive layer 15 has substantially the same shape as the substrate 11 in a plan view. That is, the adhesive layer 15 has a convex shape in a plan view. The adhesive layer 15 has a base 15A having a rectangular shape in a plan view, and a protrusion 15B having a rectangular shape in a plan view that extends from the center of the short side of the base 15A in the long side direction of the base 15A.

[0018] The substrate 11 functions as a base material for maintaining the strength and shape of the sensor sheet 1. As the substrate 11, for example, a film made of a transparent elastomer can be used. Here, "transparent" means that the light transmittance measured according to JIS K7136 is 50% or more.

[0019] The transparent elastomer is not particularly limited, and examples thereof include silicone. The transparent elastomer may be one type or two or more types.

[0020] The arithmetic mean roughness (Ra) of one main surface 11a of the substrate 11 is 0.5 μm to 1.5 μm, preferably 0.7 μm to 1.2 μm, and more preferably 0.8 μm to 1.0 μm. If the arithmetic mean roughness (Ra) of one main surface 11a of the substrate 11 is equal to or greater than the lower limit of the above range, the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrates into the minute irregularities of one main surface 11a of the substrate 11, thereby improving the adhesion of the transparent conductive layer 12 to one main surface 11a of the substrate 11 due to an anchor effect. When the arithmetic mean roughness (Ra) of one main surface 11a of the substrate 11 is equal to or less than the upper limit of the above range, the conductive ink containing PEDOT-PSS that forms the transparent conductive layer 12 penetrates into the minute irregularities on the one main surface 11a of the substrate 11, thereby selectively improving the light transmittance and haze value in the portion of the one main surface 11a of the substrate 11 where the transparent conductive layer 12 is formed.

[0021] The arithmetic mean roughness (Ra) of one main surface 11a of the substrate 11 is a value measured in accordance with JIS B0601.

[0022] The thickness of the substrate 11 is not particularly limited, but is preferably 75 μm or more and 150 μm or less, and more preferably 100 μm or more and 125 μm or less, in terms of average thickness. If the average thickness of the substrate 11 is equal to or more than the lower limit of the above range, durability is improved. If the average thickness of the substrate 11 is equal to or less than the upper limit of the above range, flexibility and light transmittance are improved. The average thickness of the substrate 11 described in this specification is the average value of thicknesses measured at any 10 points on the substrate 11.

[0023] The transparent conductive layer 12 refers to an electrode having a light transmittance of 50% or more as measured in accordance with JIS K7361. The transparent conductive layer 12 can be formed by printing a conductive paste on one main surface 11a of the substrate 11. The conductive material contained in the conductive paste is a conductive polymer. As the conductive polymer, a polythiophene-based conductive polymer is preferable, and from the viewpoint of improving transparency, conductivity, and heat resistance, PEDOT-PSS (poly(3,4-ethylenedioxythiophene-polystyrene sulfonic acid) is more preferable. In addition, the conductive paste may contain, as a conductive material, indium-doped tin oxide (ITO), etc.), conductive nanowires (silver nanowires, gold nanowires, carbon nanotubes, etc.), metal particles (silver particles, copper particles, gold particles, etc.), conductive metal oxide particles (ITO particles, etc.), carbon (carbon black, graphite, etc.), etc. It is preferable that the conductive paste contains a known binder resin that binds these conductive materials together.

[0024] The thickness of the transparent conductive layer 12 is greater than the ten-point average roughness (Rz) of one main surface 11a of the substrate 11 and is 1 μm or less, preferably 0.5 μm or more and 1.0 μm or less, and more preferably 0.6 μm or more and 0.9 μm or less. If the thickness of the transparent conductive layer 12 is equal to or greater than the lower limit of the above range, there is an advantage in that the touch sensitivity and durability are improved. If the thickness of the transparent conductive layer 12 is equal to or less than the upper limit of the above range, there is an advantage in that the light transmittance and flexibility are improved. Note that the thickness of the transparent conductive layer 12 described in this specification is the average value of thicknesses measured at any 10 points of the transparent conductive layer 12.

[0025] The ten-point average roughness (Rz) of one main surface 11a of the substrate 11 is a value measured in accordance with JIS B0601.

[0026] The refractive index difference between the substrate 11 and the transparent conductive layer 12 is not more than 0.2, preferably not more than 0.15, and more preferably not more than 0.1. If the refractive index difference between the substrate 11 and the transparent conductive layer 12 is not more than the upper limit, there is an advantage in that the light transmittance and visibility are improved.

[0027] The refractive indexes of the substrate 11 and the transparent conductive layer 12 are values ​​measured in accordance with JIS R 3106.

[0028] The auxiliary electrode layer 13 can be formed on the transparent conductive layer 12 and on one main surface 11 a of the substrate 11 by printing a non-transparent metal paste ink. Examples of conductive substances contained in the non-transparent metal paste ink include conductive nanowires (silver nanowires, gold nanowires, carbon nanotubes, etc.), metal particles (silver particles, copper particles, gold particles, etc.), conductive metal oxide particles (ITO particles, etc.), carbon (carbon black, graphite, etc.), etc. The conductive paste may contain one type of conductive substance or two or more types of conductive substances.

[0029] The thickness of the auxiliary electrode layer 13 is not particularly limited, but is preferably 1 μm or more and 20 μm or less, and more preferably 8 μm or more and 15 μm or less, in average thickness, for example. If the average thickness of the auxiliary electrode layer 13 is equal to or more than the lower limit of the above range, the touch sensitivity is improved. If the average thickness of the auxiliary electrode layer 13 is equal to or less than the upper limit of the above range, the bending durability is improved. Note that the average thickness of the auxiliary electrode layer 13 described in this specification is the average value of thicknesses measured at any 10 points of the auxiliary electrode layer 13.

[0030] The first transparent insulating layer 14 covers one main surface 11a of the base material 11 on which the transparent conductive layer 12 and the auxiliary electrode layer 13 are arranged, so as to embed the transparent conductive layer 12 and the auxiliary electrode layer 13. Here, "transparent" means that the light transmittance measured according to JIS K7136 is 50% or more.

[0031] The material (first transparent insulating material) constituting the first transparent insulating layer 14 is not particularly limited as long as it can protect the transparent conductive layer 12 and the auxiliary electrode layer 13, and examples of such materials include polyester resin, acrylic resin, urethane resin, epoxy resin, polyolefin resin, etc. The resin contained in the first transparent insulating layer 14 may be one type or two or more types.

[0032] The shape and dimensions of the first transparent insulating layer 14 are not particularly limited, and can be appropriately determined depending on the shapes of the transparent conductive layer 12 and the auxiliary electrode layer 13, etc. The average thickness of the first transparent insulating layer 14 is preferably 10 μm or more and 30 μm or less, more preferably 15 μm or more and 25 μm or less. If the average thickness of the first transparent insulating layer 14 is equal to or more than the lower limit of the above range, sufficient strength is obtained, and the effect of suppressing peeling of the transparent conductive layer 12 and the auxiliary electrode layer 13 from the substrate 11 and the effect of protecting the transparent conductive layer 12 and the auxiliary electrode layer 13 are easily obtained. If the average thickness of the first transparent insulating layer 14 is equal to or less than the upper limit of the above range, the sensor sheet 1 can be easily thinned. Note that the average thickness of the first transparent insulating layer 14 described in this specification is the average value of thicknesses measured at any 10 points of the portion covering the transparent conductive layer 12 and the auxiliary electrode layer 13 in the first transparent insulating layer 14.

[0033] The adhesive layer 15 is for adhering the sensor sheet to an object to be adhered. The material constituting the adhesive layer 15 is not particularly limited, and may be, for example, an anisotropic conductive adhesive.

[0034] The thickness of the adhesive layer 15 is not particularly limited, but is preferably 30 μm or more and 60 μm or less, and more preferably 40 μm or more and 50 μm or less, in terms of average thickness. If the average thickness of the adhesive layer 15 is equal to or more than the lower limit of the above range, strong adhesive strength is obtained. If the average thickness of the adhesive layer 15 is equal to or less than the upper limit of the above range, flexibility is improved. The average thickness of the adhesive layer 15 described in this specification is the average value of thicknesses measured at any 10 points of the adhesive layer 15.

[0035] In the sensor sheet 1 of this embodiment, the arithmetic mean roughness (Ra) of one main surface 11a of the substrate 11 is 0.5 μm or more and 1.5 μm or less, and the transparent conductive layer 12 is disposed on the one main surface 11a of the substrate 11. As a result, the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrates into the minute unevenness of the one main surface 11a of the substrate 11, and the adhesion of the transparent conductive layer 12 to the one main surface 11a is improved by the anchor effect. As a result, the sensor sheet 1 of this embodiment has excellent conformability to a three-dimensional curved surface structure. In addition, the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrates into the minute unevenness of the one main surface 11a of the substrate 11, and the light transmittance and haze value are selectively improved in the portion of the one main surface 11a of the substrate 11 where the transparent conductive layer 12 is formed.

[0036] According to the sensor sheet 1 of this embodiment, the first transparent insulating layer 14 is disposed on the transparent conductive layer 12 and the auxiliary electrode layer 13, and covers the transparent conductive layer 12 and the auxiliary electrode layer 13 in a plan view of the substrate 11, thereby preventing the transparent conductive layer 12 and the auxiliary electrode layer 13 from peeling off from their respective ends. In addition, the transparent conductive layer 12 is prevented from sticking to a screen printing plate or metal printing plate, improving printability.

[0037] An example of a method for producing the sensor sheet 1 of this embodiment will be described below. The method for producing the sensor sheet 1 illustrated in FIG. 1 is not particularly limited, and may be, for example, a method including the following steps (a) to (d). Step (a): Transparent conductive layer forming step: A transparent conductive layer 12 is formed on at least one main surface 11a of a substrate 11 by mesh screen printing or metal plate printing using a conductive ink containing PEDOT-PSS. Step (b): Auxiliary electrode layer forming step: An auxiliary electrode layer 13 is formed on the transparent conductive layer 12 and on one main surface 11a of the substrate 11 using a non-transparent metal paste ink so as to cover at least a portion of the periphery of the transparent conductive layer 12. Step (c): First transparent insulating layer forming step: A first transparent insulating layer 14 is formed on the transparent conductive layer 12 and the auxiliary electrode layer 13 using a first transparent insulating material, so as to cover the transparent conductive layer 12 and the auxiliary electrode layer 13 when viewed in a plane of the substrate 11. Step (d): Adhesive Layer Forming Step: An adhesive layer 15 is formed with an adhesive on the surface (other main surface) 11b of the substrate 11 opposite to the surface on which the transparent conductive layer 12 is disposed.

[0038] In step (a), the mesh number of the screen printing plate used in the mesh screen printing is 80 to 600, preferably 120 to 500, and more preferably 200 to 400. If the mesh number is equal to or greater than the lower limit, the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrates into the minute irregularities on one main surface 11a of the substrate 11, thereby improving the adhesion of the transparent conductive layer 12 to the one main surface 11a by an anchor effect. If the mesh number is equal to or less than the upper limit, the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrates into the minute irregularities on one main surface 11a of the substrate 11, thereby selectively improving the light transmittance and haze value in the portion of the one main surface 11a of the substrate 11 where the transparent conductive layer 12 is formed. Here, mesh count means the number of threads per inch. It is usually counted as 80 mesh, 100 mesh, etc.

[0039] In step (a), the thickness of the metal printing plate used in the metal printing is 5 μm or less. If the thickness of the metal printing plate is equal to or less than the upper limit, the conductive ink containing PEDOT-PSS that forms the transparent conductive layer 12 penetrates into the minute irregularities on one main surface 11a of the substrate 11, and the light transmittance and haze value are selectively improved in the portion of the one main surface 11a of the substrate 11 where the transparent conductive layer 12 is formed.

[0040] In step (a), after printing of the conductive ink, a plate release process is performed in which the screen printing plate or metal printing plate is peeled off from the substrate.

[0041] In step (b), the method for printing the non-transparent metal paste ink on the transparent conductive layer 12 and on one of the main surfaces 11a of the substrate 11 is not particularly limited, and any conventionally known method such as screen printing, gravure printing, inkjet printing, etc. can be used without any restrictions. Among these methods, from the viewpoints of suppressing the electrical resistance low and reducing the manufacturing cost, it is preferable to form the auxiliary electrode layer 13 by printing the non-transparent metal paste ink on the transparent conductive layer 12 and on one of the main surfaces 11a of the substrate 11 using the screen printing method.

[0042] In step (c), the printing method for forming the first transparent insulating layer 14 on the transparent conductive layer 12 and the auxiliary electrode layer 13 is not particularly limited, and any conventionally known method such as screen printing, gravure printing, inkjet printing, etc. can be used without any restrictions. Among these methods, from the viewpoint of reducing manufacturing costs, it is preferable to form the first transparent insulating layer 14 by printing the first transparent insulating material on the transparent conductive layer 12 and the auxiliary electrode layer 13 using the screen printing method.

[0043] In step (d), the printing method for forming the adhesive layer 15 on the other main surface 11b of the substrate 11 is not particularly limited, and any conventionally known method such as screen printing, gravure printing, inkjet printing, etc. can be used without any restrictions. Among these methods, from the viewpoint of reducing manufacturing costs, it is preferable to form the adhesive layer 15 by printing an anisotropic conductive adhesive on the other main surface 11b of the substrate 11 using the screen printing method.

[0044] According to the manufacturing method of the sensor sheet 1 of this embodiment, in step (a), by using a screen printing plate having a mesh number of 80 or more and 325 or less, the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrates into the minute irregularities on one main surface 11a of the substrate 11, thereby improving the adhesion of the transparent conductive layer 12 to the one main surface 11a by an anchor effect. In addition, by the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrating into the minute irregularities on one main surface 11a of the substrate 11, the light transmittance and haze value are selectively improved in the portion of the one main surface 11a of the substrate 11 where the transparent conductive layer 12 is formed.

[0045] According to the manufacturing method of the sensor sheet 1 of this embodiment, in step (a), by using a metal printing plate having a plate thickness of 5 μm or less, the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrates into the minute irregularities on one main surface 11a of the substrate 11, thereby improving the adhesion of the transparent conductive layer 12 to the one main surface 11a by an anchor effect. In addition, by the conductive ink containing PEDOT-PSS forming the transparent conductive layer 12 penetrating into the minute irregularities on one main surface 11a of the substrate 11, the light transmittance and haze value are selectively improved in the portion of the one main surface 11a of the substrate 11 where the transparent conductive layer 12 is formed.

[0046] According to the manufacturing method of the sensor sheet 1 of this embodiment, in step (a), after printing the conductive ink, the screen printing plate or metal printing is peeled off from the substrate, thereby preventing the transparent conductive layer 12 from sticking to the screen printing plate or metal printing, improving printability.

[0047] [Second embodiment] Fig. 2 is a schematic diagram showing a second embodiment of the sensor sheet according to the present invention, where (a) is a plan view, (b) is a cross-sectional view taken along line BB in (a), and (c) is a back view. In Fig. 2, the same components as those shown in Fig. 1 are designated by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 2, the sensor sheet 100 of this embodiment includes a substrate 11, a transparent conductive layer 12, an auxiliary electrode layer 13, a first transparent insulating layer 14, an adhesive layer 15, and a second transparent insulating layer 16. In the example shown in Figure 2, in addition to the sensor sheet 1 of the first embodiment shown in Figure 1, it further includes a second transparent insulating layer 16 that is disposed between the substrate 11 and the transparent conductive layer 12 and covers the transparent conductive layer 12 when viewed in a plane of the substrate 11.

[0048] The second transparent insulating layer 16 is disposed on one main surface 11 a of the base material 11 . The second transparent insulating layer 16 has substantially the same shape as the base material 11 in a plan view.

[0049] The thickness of the second transparent insulating layer 16 is greater than the ten-point average roughness (Rz) of at least one of the main surfaces 11a of the substrate 11, and is preferably 10 μm or more, and more preferably 30 μm or more. If the thickness of the second transparent insulating layer 16 is equal to or greater than the lower limit of the above range, durability is improved. If the thickness of the second transparent insulating layer 16 is equal to or less than the upper limit of the above range, light transmittance and flexibility are improved. Note that the thickness of the second transparent insulating layer 16 described in this specification is the average value of thicknesses measured at any ten points of the second transparent insulating layer 16.

[0050] In addition to the sensor sheet 1 of the first embodiment, the sensor sheet 100 of this embodiment further includes a second transparent insulating layer 16 between the substrate 11 and the transparent conductive layer 12, covering the transparent conductive layer 12. As a result, one main surface of the second transparent insulating layer 16 penetrates into the minute irregularities of one main surface 11a of the substrate 11, thereby improving the adhesion between the substrate 11 and the second transparent insulating layer 16. Since the transparent conductive layer 12 having PEDOT-PSS is formed on the other main surface of the second transparent insulating layer 16, the adhesion between the substrate 11 and the transparent conductive layer 12 can be improved as a result. In addition, the mechanism of improving wettability can increase the conductivity of the transparent conductive layer 12 and improve the reliability of the conductive path.

[0051] An example of a method for manufacturing the sensor sheet 100 of this embodiment will be described below. The method for manufacturing the sensor sheet 100 illustrated in FIG. 2 is not particularly limited, and for example, in addition to the steps (a) to (d) described in the method for manufacturing the sensor sheet 1 of the first embodiment, a method including the step (e) shown below can be used.

[0052] Step (e): Second transparent insulating layer forming step: Before step (a), a second transparent insulating layer 16 is formed between the substrate 11 and the transparent conductive layer 12, i.e., on one of the main surfaces 11a of the substrate 11, so as to cover the transparent conductive layer 12 when viewed in a plane of the substrate 11.

[0053] In step (e), the printing method for forming the second transparent insulating layer 16 on one main surface 11a of the substrate 11 is not particularly limited, and any conventionally known method such as screen printing, gravure printing, inkjet printing, etc. can be used without any restrictions. Among these methods, from the viewpoint of reducing manufacturing costs, it is preferable to use the screen printing method to print the second transparent insulating material on one main surface 11a of the substrate 11 to form the second transparent insulating layer 16. As the second transparent insulating material, the same material as the first transparent insulating material is used.

[0054] According to the manufacturing method of the sensor sheet 100 of this embodiment, in step (e), a second transparent insulating layer 16 is formed on one of the main surfaces 11a of the substrate 11, thereby improving the film thickness / conductive path that was reduced by the conductive ink containing PEDOT-PSS that forms the transparent conductive layer 12 penetrating into the minute irregularities on one of the main surfaces 11a of the substrate 11.

[0055] [Third embodiment] 3 is a schematic diagram showing a third embodiment of the sensor sheet according to the present invention, where (a) is a plan view, (b) is a cross-sectional view taken along line CC in (a), and (c) is a back view. In Fig. 3, the same components as those shown in Fig. 1 are designated by the same reference numerals, and the description thereof will be omitted. As shown in Figure 3, the sensor sheet 200 of this embodiment includes a substrate 11, a transparent conductive layer 12, an auxiliary electrode layer 13, a first transparent insulating layer 14, an adhesive layer 15, a third transparent insulating layer 17, and a design layer 18. 3 further includes a third transparent insulating layer 17 that is disposed between the substrate 11 and the adhesive layer 15 and covers the transparent conductive layer 12 and the auxiliary electrode layer 13 in a plan view of the substrate 11, in addition to the sensor sheet 1 of the first embodiment shown in Fig. 1. Moreover, the example shown in Fig. 3 further includes a design layer 18 that is disposed between the third transparent insulating layer 17 and the adhesive layer 15, in addition to the sensor sheet 1 of the first embodiment shown in Fig. 1.

[0056] The third transparent insulating layer 17 is disposed on the other main surface 11b of the base material 11. The third transparent insulating layer 17 has substantially the same shape as the base material 11 in a plan view.

[0057] The thickness of the third transparent insulating layer 17 is greater than the ten-point average roughness (Rz) of at least one of the main surfaces 11a of the substrate 11, and is preferably 10 μm or more, and more preferably 30 μm or more. If the thickness of the third transparent insulating layer 17 is equal to or greater than the lower limit of the above range, durability is improved. If the thickness of the third transparent insulating layer 17 is equal to or less than the upper limit of the above range, light transmittance and flexibility are improved. Note that the thickness of the third transparent insulating layer 17 described in this specification is the average value of thicknesses measured at any ten points of the third transparent insulating layer 17.

[0058] The arithmetic mean roughness (Ra) of the other main surface 11b of the substrate 11 is 0.5 μm to 1.5 μm, preferably 0.7 μm to 1.2 μm, and more preferably 0.8 μm to 1.0 μm. If the arithmetic mean roughness (Ra) of the other main surface 11b of the substrate 11 is equal to or greater than the lower limit of the above range, the third insulating material forming the third transparent insulating layer 17 penetrates into minute irregularities on the other main surface 11b of the substrate 11, thereby improving the adhesion of the third transparent insulating layer 17 to the other main surface 11b of the substrate 11 due to an anchor effect. When the arithmetic mean roughness (Ra) of the other main surface 11b of the substrate 11 is equal to or less than the upper limit of the above range, the third insulating material forming the third transparent insulating layer 17 penetrates into the minute irregularities on the other main surface 11b of the substrate 11, thereby selectively improving the light transmittance and haze value in the portion of the other main surface 11b of the substrate 11 where the third transparent insulating layer 17 is formed.

[0059] The arithmetic mean roughness (Ra) of the other main surface 11b of the substrate 11 is a value measured in accordance with JIS B0601.

[0060] The design layer 18 is a layer on which any decoration such as ornaments, letters, figures, symbols, patterns, combinations of these, or combinations of these with colors is applied to the surface 17a of the third transparent insulating layer 17 opposite the substrate 11. The design layer 18 can be formed, for example, by printing on the surface 17a of the third transparent insulating layer 17 opposite the substrate 11.

[0061] In addition to the components of the sensor sheet 1 of the first embodiment, the sensor sheet 200 of this embodiment further includes a third transparent insulating layer 17 between the substrate 11 and the adhesive layer 15, the third transparent insulating layer 17 covering the transparent conductive layer 12 and the auxiliary electrode layer 13. This allows the third insulating material forming the third transparent insulating layer 17 to suppress expansion and contraction of the substrate 11, and selectively improves the rigidity of the portion of one main surface 11a of the substrate 11 where the transparent conductive layer 12 is formed. In addition, sticking to a printing stage or a working table is suppressed, eliminating the need for a transport carrier, improving workability and dimensional stability.

[0062] An example of a method for manufacturing the sensor sheet 200 of this embodiment will be described below. The method for manufacturing the sensor sheet 200 illustrated in FIG. 3 is not particularly limited, and for example, in addition to the steps (a) to (d) described in the method for manufacturing the sensor sheet 1 of the first embodiment, a method can be used that further includes the steps (f) and (g) described below.

[0063] Step (f): Third transparent insulating layer forming step: Before step (d), a third transparent insulating layer 17 is formed on the surface (other surface) 11b of the substrate 11 opposite the surface on which the transparent conductive layer 12 is arranged, so as to cover the transparent conductive layer 12 and the auxiliary electrode layer 13 in a planar view of the substrate 11. Step (g): Design Layer Forming Step: Before step (d), design layer 18 is formed between third transparent insulating layer 17 and adhesive layer 15.

[0064] In step (f), the printing method for forming the third transparent insulating layer 17 on the other main surface 11b of the substrate 11 is not particularly limited, and any conventionally known method such as screen printing, gravure printing, inkjet printing, etc. can be used without any restrictions. Among these methods, from the viewpoint of reducing manufacturing costs, it is preferable to use the screen printing method to print the third transparent insulating material on the other main surface 11b of the substrate 11 to form the third transparent insulating layer 17. As the third transparent insulating material, the same material as the first transparent insulating material is used.

[0065] In step (g), the printing method for forming the design layer between the third transparent insulating layer 17 and the adhesive layer 15, i.e., on the surface 17a of the third transparent insulating layer 17 opposite the substrate 11, is not particularly limited, and any conventionally known method such as screen printing, gravure printing, inkjet printing, etc. can be used without any restrictions. Among these methods, from the viewpoint of reducing manufacturing costs, it is preferable to use the screen printing method to print a printing ink on the surface 17a of the third transparent insulating layer 17 opposite the substrate 11 to form the design layer.

[0066] According to the manufacturing method of the sensor sheet 200 of this embodiment, in step (f), the third transparent insulating layer 17 is formed on the other main surface 11b of the base material 11, and the third insulating material forming the third transparent insulating layer 17 suppresses expansion and contraction of the base material 11, and selectively improves rigidity in the portion of the one main surface 11a of the base material 11 where the transparent conductive layer 12 is formed. In addition, sticking to the printing stage or working table is suppressed, and a transport carrier is not required, improving workability and dimensional stability. [Industrial Applicability]

[0067] The sensor sheet of the present invention has excellent conformability to three-dimensional curved structures and is therefore suitable for use in electronic devices in various fields, such as in-vehicle devices. [Explanation of symbols]

[0068] 1,100,200 Sensor sheet 11 Base material 12 Transparent conductive layer 13 Auxiliary electrode layer 14 First transparent insulating layer 15 Adhesive layer 16 Second transparent insulating layer 17 Third transparent insulating layer 18 Design Layer

Claims

1. A substrate made of a transparent elastomer; A transparent conductive layer disposed on at least one of the main surfaces of the substrate; an auxiliary electrode layer disposed on the transparent conductive layer so as to cover at least a portion of a periphery of the transparent conductive layer; a first transparent insulating layer disposed on the transparent conductive layer and the auxiliary electrode layer, the first transparent insulating layer covering the transparent conductive layer and the auxiliary electrode layer in a plan view of the base material; an adhesive layer disposed on a surface of the base opposite to a surface on which the transparent conductive layer is disposed, The arithmetic average roughness (Ra) of at least one main surface of the substrate is 0.5 μm or more and 1.5 μm or less; the transparent conductive layer is formed of a conductive ink containing PEDOT-PSS; the transparent conductive layer has a thickness greater than the ten-point average roughness (Rz) of at least one of the main surfaces of the substrate and less than or equal to 1 μm; a refractive index difference between the substrate and the transparent conductive layer is 0.2 or less; The auxiliary electrode layer is formed by a non-transparent metal paste ink.

2. a second transparent insulating layer disposed between the substrate and the transparent conductive layer and covering the transparent conductive layer in a plan view of the substrate; The sensor sheet according to claim 1 , wherein a thickness of the second transparent insulating layer is greater than a ten-point average roughness (Rz) of at least one of the main surfaces of the base material.

3. a third transparent insulating layer disposed between the base material and the adhesive layer and covering the transparent conductive layer and the auxiliary electrode layer in a plan view of the base material; The sensor sheet according to claim 1 , wherein a thickness of the third transparent insulating layer is greater than a ten-point average roughness (Rz) of at least one of the main surfaces of the base material.

4. The sensor sheet according to claim 3 , further comprising a design layer disposed between the third transparent insulating layer and the adhesive layer.

5. a transparent conductive layer forming step of forming a transparent conductive layer on at least one main surface of a substrate made of a transparent elastomer by mesh screen printing or metal plate printing using a conductive ink containing PEDOT-PSS; an auxiliary electrode layer forming step of forming an auxiliary electrode layer on the transparent conductive layer using a non-transparent metal paste ink so as to cover at least a portion of a periphery of the transparent conductive layer; a first transparent insulating layer forming step of forming a first transparent insulating layer on the transparent conductive layer and the auxiliary electrode layer using a first transparent insulating material, the first transparent insulating layer covering the transparent conductive layer and the auxiliary electrode layer in a plan view of the base material; and forming an adhesive layer on a surface of the base opposite to a surface on which the transparent conductive layer is disposed, using an adhesive. In the transparent conductive layer forming step, the mesh number of a screen printing plate used in mesh screen printing is 80 or more and 600 or less, In the transparent conductive layer forming step, the thickness of the metal printing plate used in the metal printing is 5 μm or less, A method for manufacturing a sensor sheet, wherein in the transparent conductive layer forming step, after printing of the conductive ink, a plate separation is performed by peeling the screen printing plate or the metal printing plate from the substrate.

6. 6. The method for manufacturing a sensor sheet according to claim 5, further comprising, before the transparent conductive layer forming step, a second transparent insulating layer forming step of forming a second transparent insulating layer between the substrate and the transparent conductive layer, the second transparent insulating layer covering the transparent conductive layer in a planar view of the substrate.

7. 6. The method for manufacturing a sensor sheet according to claim 5, further comprising, before the adhesive layer forming step, a third transparent insulating layer forming step of forming a third transparent insulating layer on a surface of the base material opposite to the surface on which the transparent conductive layer is arranged, the third transparent insulating layer covering the transparent conductive layer and the auxiliary electrode layer in a planar view of the base material.

8. The method for manufacturing a sensor sheet according to claim 7 , further comprising, before the adhesive layer forming step, a design layer forming step of forming a design layer between the third transparent insulating layer and the adhesive layer.

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