Touch sensor module

Abstract

To provide a touch sensor module having a light diffusion layer capable of equalizing the brightness of an internal light source passing through a sensor sheet, while also being easy to design and manufacture.SOLUTION: The touch sensor module includes an internal light source and a sensor sheet. The sensor sheet includes a base material layer, a sensor electrode, a protective layer, and a light diffusion layer. The light diffusion layer has a plurality of lens structures including acryl resin. The protruding part of the lens structure faces the direction of the internal light source.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sensor sheet having a diffusion plate and a touch sensor module including the sensor sheet. [Background technology]

[0002] Capacitive sensor sheets, which allow users to input information by touching the screen, are used in electronic devices in various fields, including in-vehicle devices. For example, a sensor sheet can be attached to the back of an operation panel to detect a user's touch operation on the operation surface of the operation panel. In sensor sheets attached to the back of operation panels illuminated by internal light sources, there have been proposals in the prior art to make the bright spots of the LED light source less visible, and Patent Document 1 discloses a configuration in which a light diffusion layer is formed to cover the sensor electrodes. The above-mentioned configuration has problems in that the diffusing components contained in the light diffusion layer cause a decrease in transmittance and the diffusion angle cannot be freely controlled. As other prior art, a diffusion plate with a large number of microlenses arranged thereon has been proposed (for example, Patent Documents 2 to 4). However, these prior arts require the production of a mold for molding or transferring the lenses, which is a complicated process, and there is also a problem that the configuration becomes complicated when combined with a sensor sheet, and there was a need to solve this problem. As a manufacturing method that does not use a mold, a method that utilizes a base material or a mold having a large number of minute partitions has been proposed (for example, Patent Document 5), but it was not possible to form an arbitrary lens pattern. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-092688 [Patent Document 2] JP 2017-9669 A [Patent Document 3] JP 2015-26072 A [Patent Document 4] JP 2011-59156 A [Patent Document 5] Japanese Patent Application Publication No. 9-49903 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a touch sensor module that is equipped with a light diffusion layer that can uniformize the brightness of an internal light source that transmits through a sensor sheet, and that is easy to design and simple to manufacture. [Means for solving the problem]

[0005] The present invention has the following aspects. [1] A touch sensor module including an internal light source and a sensor sheet, The sensor sheet includes a base layer provided at a position facing the internal light source; a sensor electrode disposed on one surface of the base layer; a protective layer disposed to cover the sensor electrode; a light diffusing layer disposed on a surface of the protective layer opposite to a surface on which the sensor electrode is disposed, The touch sensor module, wherein the light diffusion layer includes a plurality of lens structures containing an acrylic resin, and convex portions of the lens structures face toward the internal light source. [2] The touch sensor module according to [1], wherein the light diffusion layer contains a urethane acrylate UV-curable resin, and when the resin forming the light diffusion layer is formed into a specified test piece, the refractive index is 1.4 or more and 1.6 or less, and the total light transmittance is 90% or more. [3] The thickness of the light diffusion layer is 10 μm or more and 100 μm or less, The lens structure of the light diffusion layer is a substantially hemispherical lens shape or a cylindrical (substantially semi-cylindrical) structure, The diameter of the lens structure is 0.1 μm or more and 1.0 μm or less, The touch sensor module according to [1] or [2], wherein the ratio of maximum height to diameter of the lens structure is 0.05 or more and 0.1 or less. [4] The sensor sheet further includes an adhesive layer and an operation panel. When viewed from the internal light source side, the internal light source, the light diffusion layer, the protective layer, the sensor electrode, the base layer, the adhesive layer, and the operation panel are arranged in this order, The touch sensor module according to any one of [1] to [3], wherein the light diffusion layer and the protective layer are in direct contact with each other. [5] the light diffusion layer is disposed at a position overlapping with the internal light source when viewed from the operation panel side, The touch sensor module according to any one of [1] to [4], wherein a contour A of the lens structure is larger than a contour B of the sealing resin or lens of the internal light source, and the contour B is obscured by the contour A and is not visible. [6] The touch sensor module described in any one of [1] to [5], wherein the light diffusion layer has a plurality of the lens structures spaced apart from each other, and the periphery of the area of ​​the light diffusion layer in which the plurality of lens structures are formed is smaller than the periphery of the area where the internal light source illuminates the light diffusion layer. Effect of the Invention

[0006] According to the present invention, it is possible to provide a touch sensor module that is equipped with a light diffusion layer that can uniformize the luminance of an internal light source that transmits through a sensor sheet, and that is easy to design and can be manufactured simply. [Brief description of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view showing an example of a touch sensor module according to an embodiment; [Diagram 2] 4 is a cross-sectional view showing an example of a contact angle θ of a lens structure 12a with respect to the surface of a protective layer 16. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The following describes the sensor sheet according to the present invention and the touch sensor module using the same, with reference to the drawings. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios may differ from the actual ones. In addition, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and may be appropriately modified and implemented within the scope of the present invention.

[0009] The touch sensor module of this embodiment includes an internal light source and a sensor sheet. The sensor sheet comprises a base layer disposed opposite the internal light source, a sensor electrode disposed on any surface of the base layer, a protective layer disposed so as to cover the sensor electrode, and a light diffusion layer disposed on the surface of the protective layer opposite the surface on which the sensor electrode is disposed. The light diffusing layer includes a plurality of lens structures containing an acrylic resin, and convex portions of the lens structures face the internal light source. The touch sensor module of this embodiment can adopt a known embodiment except that it is provided with a sensor sheet described later. In the touch sensor module of this embodiment, for example, as shown in the embodiment of Fig. 1, the sensor sheet is attached to the back surface of an operation panel. Hereinafter, a first embodiment of the touch sensor module of the present invention will be described in detail as an example of the sensor sheet and the touch sensor module using the same.

[0010] (First embodiment) 1, the sensor sheet 1 of the first embodiment includes a base layer 10, a sensor electrode 14, a protective layer 16, and a light diffusing layer 12. The sensor electrode 14 is provided on a first surface 10a of the base layer 10. The protective layer 16 is provided on the entire first surface 10a so as to cover the sensor electrode 14. As shown in Fig. 1, the light diffusion layer 12 is disposed on the surface of the protective layer 16 opposite to the surface on which the sensor electrode 14 is disposed. As a result, the base layer 10 and an operation surface 112, which will be described in detail later, form a space on the operation surface 112 side of the base layer 10. The light diffusion layer 12 is disposed in the space on the opposite side of the base layer 10 from the space, in which the sensor electrode 14 is disposed. The light diffusion layer 12 is disposed on the protective layer 16, between the protective layer 16 and the internal light source 130. Therefore, this space is constituted by the sensor electrode 14, the protective layer 16, the light diffusion layer 12, and the internal light source 130.

[0011] The base layer 10 functions as a base material for maintaining the strength and shape of the sensor sheet 1. For example, a resin film can be used as the base layer 10. A light diffusion film can also be used as the base layer 10. In this way, when a light diffusion film is used for the base layer 10, the diffusion of light emitted from the internal light source by the sensor sheet 1 is further improved, so that characters on the operation panel can be effectively illuminated and excellent visibility can be obtained. When a light diffusion film is used for the base layer 10, the light diffusion film is not particularly limited, and for example, a resin film containing a light diffusion material can be exemplified. From the viewpoint of increasing the light transmittance of the sensor sheet 1, the base layer 10 is preferably a transparent resin film that does not contain a light diffusion material. From the viewpoint of increasing the light diffusion of the sensor sheet 1, it is preferable that the base layer 10 is a transparent resin film that contains a light diffusion material.

[0012] The resin film constituting the base layer 10 is preferably made of a transparent resin. Here, "transparent" means that the light transmittance measured in accordance with JIS K7136 is 50% or more. The resin used for the resin film is not particularly limited, and examples thereof include polyester (polyethylene terephthalate (PET) and the like), polycarbonate (PC), etc. The resin forming the resin film may be one type or two or more types.

[0013] The resin film forming the base layer 10 is preferably subjected to an easy-adhesion treatment such as ultraviolet irradiation, excimer light irradiation, corona treatment, plasma treatment, surface coating, etc. on the side of the sensor electrode 14. This facilitates adhesion to a layer provided thereon, such as the sensor electrode 14, and improves adhesion. Such easy-adhesion treatment may be performed on both sides of the base layer 10. The planar shape and size of the base layer 10 are not particularly limited, and can be appropriately set depending on the application of the sensor sheet 1.

[0014] The thickness of the base layer 10 is not particularly limited, but for example, the average thickness is preferably 10 μm or more and 250 μm or less, and more preferably 30 μm or more and 150 μm or less. If the average thickness of the base layer 10 is equal to or more than the lower limit of the above range, sufficient strength and rigidity can be easily ensured. Furthermore, if the average thickness of the base layer 10 is equal to or less than the upper limit of the above range, the sensor sheet 1 can be easily made thin. Note that the average thickness of the base layer 10 described in this specification is the average value of thicknesses measured at any 10 points on the base layer 10.

[0015] The light diffusion layer 12 has a plurality of lens structures containing at least an acrylic resin, and the convex portions of the lens structures face the internal light source side. The convex portions of the lens structures face the internal light source side, improving the light collection efficiency and providing a stronger irradiation and light distribution effect. The light diffusion layer 12 has a function of diffusing the light emitted from the internal light source 130, which is a backlight.

[0016] 1, the light diffusion layer 12 has a plurality of lens structures spaced apart from each other to form a minute lens array. In this specification, the light diffusion layer 12 refers to a region in which a plurality of lens structures are formed. This allows the lens array to be arranged in a diffused manner on the surface of the base layer 10, and these are integrated to form a diffusion plate, which makes it possible to suppress unevenness in the brightness of internal light sources such as LEDs and achieve uniform brightness without reducing light transmittance.

[0017] The minute lens array in the light diffusion layer 12 has a structure in which a plurality of microlenses (lens structures 12a) each having a size of several tens of μm are arranged at regular intervals, and functions as a diffusion plate that diffuses and homogenizes the light emitted from the light source. The intervals between the individual microlenses are, for example, preferably 200 μm to 2000 μm, more preferably 300 μm to 600 μm, and even more preferably 330 μm to 450 μm. Within these preferred ranges, the light converging effect, light collecting effect, and light distribution effect can be further improved.

[0018] The diameter of the lens structure 12a can be appropriately selected, but is preferably 200 μm to 800 μm, more preferably 220 μm to 300 μm. Within these preferred ranges, the light converging effect, light collecting effect, and light distribution effect can be further improved. Here, the diameter of lens structure 12a refers to the length across the contour of each lens structure (if the contour of the lens structure is circular, its diameter) when viewed in a direction looking down on the main surface of protective layer 16 on which lens structure 12a is provided (in the height direction of lens structure 12a).

[0019] Reference is now made to Figure 2. The contact angle θ formed between the lens structure 12a after curing and the ground surface (first surface 10a of the substrate layer) is preferably, for example, 30 degrees or more. It is more preferably 35 degrees or more, and even more preferably 40 degrees or more. There is no particular upper limit, but it is usually 90 degrees or less. Within these preferred ranges, the light converging effect, light collecting effect, and light distribution effect can be further improved.

[0020] The ratio of the maximum height to the diameter of the lens structure is not particularly limited. It is preferably 0.05 to 0.1, more preferably 0.07 to 0.09. Within these preferred ranges, the light converging effect, light collecting effect, and light distribution effect can be further improved. Here, the height of lens structure 12a refers to the length in the perpendicular direction to the main surface of protective layer 16. The top surface of lens structure 12a has a convex structure toward the internal light source side, and the length from the most bulging apex of the top surface to the bottom surface of lens structure 12a that contacts protective layer 16 is the maximum height.

[0021] The contour shape of each lens structure 12a constituting the microlens array may be circular or noncircular when the main surface of the protective layer 16 is viewed in plan. The noncircular shape may be elliptical, may have corners, or may be an irregular shape. Specifically, for example, the lens structure may be circular, elliptical, or may have three to nine or more corners. As each lens structure, a triangle, a square, a rectangle, a rhombus, or a regular polygon is preferably selected.

[0022] The three-dimensional shape of each lens structure 12a may be an approximately hemispherical lens shape or an approximately hemicylindrical structure. Here, the approximately hemispherical lens shape is a structure in which a flat portion of the hemisphere is in contact with the main surface of the protective layer 16, and a spherical portion faces the internal light source 130. The approximately hemispherical structure is a structure in which a circle constituting the top and bottom surfaces of a cylinder is cut along the height direction of the cylinder, and the flat portion, which is the cut surface, is in contact with the main surface of the protective layer 16, and the side surface of the cylinder faces the internal light source 130.

[0023] The lens structures 12a constituting the microlens array may have the same shape or different shapes. The arrangement of the lens structures in the microlens array may be random or regular at regular intervals, and can be appropriately selected depending on the application and purpose.

[0024] The lens structure 12a is preferably made of a resin, or may be made of a diffusion agent (light diffusion agent) and a resin (binder resin). The diffusing agent (light diffusing agent) contained in the lens structure 12a is not particularly limited. For example, titanium oxide, silica, hollow silica, barium titanate, barium sulfate, silicone powder, resin beads, hollow porous particles, etc. can be mentioned. For example, acrylic resin beads or styrene resin beads can be used as the resin beads. Furthermore, acrylic or styrene based particles can be used as the hollow porous particles. As the diffusing agent contained in the lens structure 12a, only one of the above-mentioned types may be used, or two or more types may be used.

[0025] The resin contained in the lens structure 12a is not particularly limited. For example, at least one selected from the group consisting of polyester resin, acrylic resin, urethane resin, epoxy resin, and polyolefin resin can be used. As the resin contained in the lens structure 12a, only one of the above resins may be used, or two or more of them may be used. A particularly preferred material for the lens structure 12a is a urethane acrylate UV-curable resin, which has excellent transparency and adhesion, and is easy to adjust to a desired refractive index.

[0026] The refractive index of the resin that is the constituent material of the lens structure 12a can be measured by preparing a specified test piece from the resin and following JIS K7142, Method A. Here, the "specified test piece" refers to one prepared according to the method described in JIS K7142, Method A.

[0027] When it is desired to adjust the refractive index of the material constituting the lens structure 12a, for example, a high refractive index layer (light diffusing layer 12 having a high refractive index lens structure 12a) or a low refractive index layer can be formed by using the following materials. The refractive index of the lens structure 12a is not particularly limited. When forming a low refractive index layer, for example, a metal fluoride such as magnesium fluoride (MgF2) or aluminum fluoride (AlF3), silicon oxide (SiO2), silicone resin, etc. are mixed with the above-mentioned constituent material, or the lens structure 12a is vapor-deposited or sputtered on the surface of the lens structure 12a. In this case, the refractive index of the constituent material of the lens structure 12a is preferably about 1.35 to 1.45. When forming a high refractive index layer, it is preferable to form it using, for example, an epoxy acrylate-based ultraviolet curing resin, a urethane-based ultraviolet curing resin having a high refractive index due to the addition of a metal oxide, an ultraviolet curing resin having a high refractive index due to the addition of titanium oxide (TiO2), etc. In this case, the refractive index of the material constituting the lens structure 12a is preferably about 1.56 to 1.7. As described above, a low refractive index layer or a high refractive index layer can be formed, but the refractive index of the material constituting the lens structure 12a is usually in the range of 1.4 to 1.6.

[0028] The material constituting the lens structure 12a is preferably transparent. Here, "transparent" means that the light transmittance measured according to JIS K7136 is 50% or more. In particular, the light transmittance is preferably 80% or more, and more preferably 90% or more.

[0029] The amount of the diffusing agent relative to the total mass of the mixed material constituting lens structure 12a is not particularly limited, but is preferably in the range of 1 to 20 mass %, and more preferably in the range of 3 to 10 mass %. If the amount of the diffusing agent in the mixed material constituting lens structure 12a is equal to or greater than the lower limit of the above range, sufficient light diffusion characteristics can be obtained and the relative dielectric constant of lens structure 12a can be effectively reduced. If the amount of the diffusing agent in lens structure 12a is equal to or less than the upper limit of the above range, the mechanical strength of lens structure 12a can be sufficiently ensured.

[0030] The sensor electrodes 14 detect contact or proximity of a conductor and are spaced apart from each other. The sensor electrodes 14 are provided on either surface of the base layer 10. The sensor electrode 14 may be of a self-capacitance type or a mutual capacitance type. The form of the self-capacitance type sensor electrode 14 is not particularly limited, and may be, for example, a solid electrode having a circular, elliptical, or rectangular shape, or a diamond pattern. The form of the mutual capacitance type sensor electrode 14 is not particularly limited, and may be, for example, a solid electrode having a circular, elliptical, or rectangular shape, or a comb-shaped electrode.

[0031] The sensor electrode 14 is preferably a transparent electrode from the viewpoint of efficiently illuminating the operation panel. A transparent electrode means an electrode having a light transmittance of 50% or more measured according to JIS K7361. The sensor electrode 14 may be an electrode having a light transmittance of less than 50%.

[0032] The sensor electrode 14 can be formed by printing a conductive paste on either surface of the base layer 10, and can be, for example, a transparent conductive film. In this specification, "conductive" means that the electrical resistance is less than 1 MΩ. Examples of conductive substances contained in the conductive paste include conductive polymers (polythiophene conductive polymers (PEDOT / PSS), 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. The conductive paste may contain one type of conductive substance or two or more types of conductive substances.

[0033] The thickness of the sensor electrode 14 is not particularly limited. For example, the average thickness is preferably 0.05 μm or more and 30 μm or less, and more preferably 0.1 μm or more and 20 μm or less. If the average thickness of the sensor electrode 14 is equal to or more than the lower limit of the above range, disconnection is easily suppressed. If the average thickness of the sensor electrode 14 is equal to or less than the upper limit of the above range, the sensor sheet can be easily made thinner. The average thickness of the sensor electrode is the average value of thicknesses measured at any ten points of the sensor electrode 14.

[0034] The protective layer 16 covers the surface of the base layer 10 on which the sensor electrodes 14 are arranged so as to embed the sensor electrodes 14 . The material constituting the protective layer 16 is preferably transparent. Here, "transparent" means that the light transmittance measured according to JIS K7136 is 50% or more. There is no particular limitation on the material constituting the protective layer 16. Any material that can protect the sensor electrode 14 may be used, and examples of such materials include polyester resin, acrylic resin, urethane resin, epoxy resin, and polyolefin resin. The resin contained in the protective layer 16 may be one type or two or more types.

[0035] There is no particular limitation on the shape and size of the protective layer 16. The shape and size can be appropriately set depending on the shape of the sensor electrode 14, etc. The average thickness of the protective layer 16 is preferably 0.1 μm or more and 80 μm or less, and more preferably 1 μm or more and 30 μm or less. If the average thickness of the protective layer 16 is equal to or more than the lower limit of the above range, sufficient strength is obtained, and the protective effect of the sensor electrode 14 is easily obtained. If the average thickness of the protective layer 16 is equal to or less than the upper limit of the above range, the sensor sheet can be easily made thinner. The average thickness of the protective layer is the average value of thicknesses measured at any ten points on the portion of the protective layer covering the sensor electrode.

[0036] The material of the adhesive layer 18 is not particularly limited, and examples thereof include a known curing adhesive (a liquid adhesive before adhesion) and a pressure-sensitive adhesive (a gel-like pressure-sensitive adhesive before adhesion). Each adhesive layer may be a substrate-type adhesive layer in which an adhesive or pressure-sensitive adhesive is disposed on both sides of a substrate sheet. An example of the substrate-type adhesive layer is a known double-sided tape.

[0037] The adhesive and pressure sensitive adhesive are not particularly limited, and examples thereof include acrylic resin, urethane resin, and ethylene-vinyl acetate copolymer. The curable adhesive may be a solvent type that contains a solvent that volatilizes during curing, or may be a hot melt type or a UV curable type.

[0038] The average thickness of the adhesive layer 18 is preferably 1 μm or more and 300 μm or less, and more preferably 10 μm or more and 165 μm or less. If the average thickness of the adhesive layer 18 is equal to or more than the lower limit of the above range, sufficient adhesive strength is easily obtained. If the average thickness of the adhesive layer 18 is equal to or less than the upper limit of the above range, the sensor sheet can be easily made thin. The average thickness of the adhesive layer is the average value of thicknesses measured at any 10 points on the adhesive layer.

[0039] [Sensor module manufacturing method] 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 is not particularly limited, and may be, for example, a method including the following steps (a) to (c). Step (a): A conductive paste is printed on the first surface 10a of the base layer 10 to form the sensor electrode 14. Step (b): An ink containing a resin is printed on the first surface 10a of the base material layer 10 to form a protective layer 16 so as to cover the sensor electrodes 14. Step (c): A mixed material preferably containing an acrylic resin is prepared, and the mixed material is printed on the surface of the protective layer 16 opposite to the surface on which the sensor electrode 14 is disposed, to form the light diffusing layer 12 .

[0040] In the above step (a), the method of printing the conductive paste on the first surface 10a of the base layer 10 is not particularly limited. As the method of printing the conductive paste, for example, a conventionally known method such as a screen printing method, a gravure printing method, an inkjet printing method, etc. can be adopted without any limitation. Among these methods, from the viewpoint of suppressing the electrical resistance low and reducing the manufacturing cost, it is preferable to print the conductive paste on the base layer 10 by using a screen printing method to form the sensor electrode 14.

[0041] In the above step (b), the printing method of ink for forming the protective layer 16 on the first surface 10a of the base layer 10 is not particularly limited. As the printing method of ink for forming the protective layer 16, for example, a conventionally known method such as a screen printing method, a gravure printing method, an inkjet printing method, etc. can be adopted without any limitation. Among these methods, from the viewpoint of reducing the manufacturing cost, it is preferable to print the ink on the base layer 10 by using a screen printing method to form the protective layer 16.

[0042] In the above step (c), as a method for preparing the mixed material preferably containing an acrylic resin, a method similar to that used for preparing a conventionally known resin film material can be adopted. The method of printing the mixed material on the first surface 10a of the base layer 10 is not particularly limited. For example, a conventionally known method such as a screen printing method, a gravure printing method, or an inkjet printing method can be used without any restrictions. Among these methods, it is preferable to print the mixed material on the base layer 10 using a screen printing method to form the light diffusion layer 12, from the viewpoints of productivity and ease of preparation of the mixed material.

[0043] The light diffusing layer 12 can be manufactured by screen printing. A mesh screen plate or a metal plate can be used for the screen printing. In this way, by manufacturing the light diffusing layer 12 by screen printing using a mesh screen plate or a metal plate, any lens patterning is possible. In screen printing using a mesh screen, a screen plate can be used in which a mesh that is permeable to the curable resin has a material, such as an emulsion, that is disposed and coated over the entire non-printing area of ​​the mesh to prevent the paste from seeping out. The curable resin is applied to the substrate through the screen plate by a squeegee. This makes it easy to form a resin pattern to be printed having a desired thickness. Screen printing using a metal plate is not particularly limited to a particular method, and known techniques can be applied. For example, it may be a combination plate in which a metal mask is fixed to a screen mesh, or a screen mesh on which a mask is formed using a photosensitive emulsion. It can also be applied to a full metal plate that does not have a screen mesh portion.

[0044] In the light diffusion layer 12, the screen mesh can be formed of a material containing, for example, any one of polyester (Tetron), nylon, and polyimide. It may be formed of a material containing metal fibers such as stainless steel. The warp and weft of the mesh may be made of stainless steel or other threads with different strengths, or two pairs of warp and weft of the mesh may be woven together. The mesh number can be, for example, 60 to 420. If the mesh number is small, the amount of ink used can be reduced, and if the mesh number is large, fine printing can be realized. When performing a large number of printings easily with high precision, the mesh number is preferably in the range of 80 to 325, more preferably 80 to 250, and even more preferably 80 to 200. Here, mesh count means the number of threads per inch. It is usually counted as 80 mesh, 120 mesh, etc.

[0045] Regarding the mesh screen plate and the metal plate, the aspect ratio between the plate thickness (emulsion thickness) and the width (diameter) of the opening through which the ink, which is the liquid material of the light diffusion layer 12, passes is preferably such that printing can be performed without causing cohesive failure of the ink, the film is thick and has a sufficient height, and the pattern edges are steep and the cross section is rectangular. Specifically, for example, the aspect ratio is preferably 0.05 to 1, more preferably 0.06 to 0.9, and even more preferably 0.07 to 0.8.

[0046] Examples of materials for the metal plate include stainless steel (SUS), nickel, phosphor bronze, and copper. The thickness of the metal plate can also be determined arbitrarily, but is preferably from 50 μm to 300 μm, more preferably from 50 μm to 250 μm, and even more preferably from 50 μm to 200 μm.

[0047] In the light diffusion layer 12, the method of curing the printed resin pattern includes, for example, heating, exposure, etc., and exposure can be preferably adopted since it is relatively easy to carry out the steps continuously. As a light source for photocuring (exposure), a light source that emits light with the absorption wavelength of the polymerization initiator and sensitizer used can be used, and a light source having a wavelength in the range of 200 nm to 450 nm (for example, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, a high power metal halide lamp, a xenon lamp, a carbon arc lamp, a light emitting diode, etc.) can be usually used. Alternatively, UV curing can be used, and the integrated light amount in this case can be, for example, 100 mJ / cm. 2 The above can be mentioned.

[0048] The contact angle θ formed between the lens structure 12a after curing and the ground surface is preferably, for example, 30 degrees or more. More preferably, it is 35 degrees or more, and even more preferably, it is 40 degrees or more. There is no particular upper limit, but it is usually 90 degrees or less. In order to set the contact angle θ in the above range, the number of meshes, the aspect ratio, the thickness of the metal plate, and the like in the screen printing are adjusted to preferred ranges. When the contact angle θ is within these preferred ranges, the light convergence effect, light collection effect, and light distribution effect can be further improved.

[0049] According to the sensor sheet 1 of the first embodiment described above, the light diffusing layer 12 forming the minute lens array as described above is provided, and thus the light transmittance is improved. Conventionally, the light diffusing layer containing a diffusing component such as titanium oxide filler covered the entire surface of the base layer (i.e., was formed by solid coating), so that all of the light from the internal light source was diffused and a part of it could not be transmitted. Therefore, the light transmittance of the sensor sheet 1 was low. On the other hand, in this embodiment, the light diffusing layer 12 is formed of a plurality of lens structures spaced apart from each other, so that a part of the light from the internal light source is diffused, and the remaining part can pass through the gaps between the lens structures without being diffused and go straight and be transmitted. By this mechanism, it is possible to suppress unevenness in the brightness of the internal light source such as an LED and to flatten the brightness without reducing the light transmittance of the sensor sheet 1. In addition, since it is manufactured by screen printing using a mesh screen or metal plate, any lens patterning is possible depending on the purpose. Since the sensor and the diffusion plate can be integrated by manufacturing it in a continuous or consistent printing process, the positional relationship between the lens pattern and the internal light source such as an LED can be accurately set, making the brightness of the internal light source that passes through the sensor sheet uniform.

[0050] [Touch sensor module] 1, an adhesive layer 18 is provided on the surface opposite to the first surface 10a of the base layer 10. With this configuration, the sensor sheet 1 can be easily attached to an operation panel by adhesion.

[0051] As shown in FIG. 1, the touch sensor module 100 (hereinafter also referred to as “module 100”) of this embodiment includes an operation panel 110 having an operation surface 112, a frame member 120, an internal light source 130, a spring 140, and a sensor sheet 1.

[0052] In the module 100 of this embodiment, as viewed from the internal light source side, the internal light source 130, the light diffusion layer 12, the protective layer 16, the sensor electrode 14, the base material layer 10, the adhesive layer 18, and the operation panel 110 are arranged in this order. In addition, in this arrangement, it is more preferable that there is no air layer or a bonding base material layer between the light diffusion layer and the protective layer, and the light diffusion layer and the protective layer are directly in contact with each other. With this configuration, the light diffusion layer can be manufactured by a printing process, so that the manufacturing can be simplified. In addition, by manufacturing by a continuous / consistent printing process, the layer functioning as a sensor and the layer functioning as a diffusion plate can be integrated.

[0053] According to the touch sensor module of this embodiment, the light diffusion layer 12 has a plurality of lens structures spaced apart from each other, forming a micro lens array, which makes it possible to suppress unevenness in the brightness of internal light sources such as LEDs and achieve uniform brightness without reducing light transmittance. In addition, since it is manufactured by screen printing using a mesh screen or metal plate, it has a configuration that allows arbitrary lens patterning. With this configuration, the layer that functions as a sensor and the layer that functions as a diffusion plate can be integrated by manufacturing it in a continuous or consistent printing process. This makes it possible to accurately set the positional relationship between the lens pattern and the internal light source such as an LED light source, and to uniform the brightness within the sensor sheet.

[0054] In the module 100 of this embodiment, the operation panel 110 and the frame member 120 are fixed by a spring 140 while being spaced apart from each other. The sensor sheet 1 is attached to the back surface of the operation panel 110 via an adhesive layer 18 provided on the second surface 10b of the base material layer 10. In the module 100, the surface of the operation panel 110 opposite the sensor sheet 1 serves as an operation surface 112. A touch operation on the operation surface 112 of the operation panel 110 can be detected by a change in capacitance of the sensor electrodes 14 of the sensor sheet 1.

[0055] The method for attaching the sensor sheet 1 to the operation panel 110 is not particularly limited, and examples include a diaphragm method and a roller method. Among them, the diaphragm method is preferable because it is easy to prevent air bubbles from being mixed between the adhesive layer 18 of the sensor sheet 1 and the operation panel 110 and it is easy to attach the sensor sheet 1 neatly.

[0056] The operation panel 110 is not particularly limited, and may be, for example, a panel body and a decorative layer formed on the surface of the panel body. Examples of materials constituting the panel body include resins such as PC and acrylic resin, and glass.

[0057] The average thickness of the panel body is preferably 0.05 mm or more and 10 mm or less, and more preferably 2 mm or more and 5 mm or less. If the thickness of the panel body is equal to or more than the lower limit of the above range, sufficient strength is easily obtained. If the thickness of the panel body is equal to or less than the upper limit of the above range, it is easy to prevent the module 100 from becoming excessively thick.

[0058] The decorative layer is a layer on which any decoration is applied, such as decorations, characters, figures, symbols, patterns, combinations of these, or combinations of these with colors. The decorative layer can be formed, for example, by printing on the panel body. Note that the operation panel 110 does not necessarily have to have a decorative layer.

[0059] Examples of materials that form the frame member 120 include resin, glass, and inorganic substances. Examples of resins that form the frame member include the same resins as those exemplified as the resins that form the panel main body.

[0060] In the module 100, an internal light source 130 is disposed on the sensor sheet 1 side of the frame member 120, opposite the operation panel 110 of the sensor sheet 1. As a result, in the module 100, light emitted from the internal light source 130 is diffused by the light diffusion layer 12 of the sensor sheet 1, and characters and the like on the operation surface 112 of the operation panel 110 are illuminated. Moreover, it is more preferable that lens structure 12a constituting light diffusion layer 12 is also disposed at a position overlapping internal light source 300 when viewed from the operation panel 110 side, and that contour A of lens structure 12a is larger than contour B of the sealing resin or lens of the internal light source, and contour B is obstructed and not visible by contour A. In this embodiment, light directly above the internal light source such as an LED can always pass through lens structure 12a of light diffusion layer 12.

[0061] In the light diffusion layer 12, it is more preferable that the periphery of the region of the light diffusion layer where the multiple lens structures 12a are formed, i.e., the periphery of the region to be illuminated, is smaller than the periphery of the region where the internal light source 300 such as an LED illuminates the bottom surface of the light diffusion layer 12. In this embodiment, the internal light source 300 does not deviate from the region illuminated. This allows the entire sensor sheet to be illuminated uniformly without creating a region with low brightness. In addition, the outline of the microlens periphery can be made less noticeable.

[0062] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, a capacitance detection unit (IC) may be provided on the surface of the frame member 120 facing the sensor sheet 1, and the frame member 120 may serve as a control board. Furthermore, the control board may be connected to the sensor sheet 1 via a connector. [Explanation of symbols]

[0063] 1...sensor sheet, 10, 10a, 10b...base material layer, 12...light diffusion layer, 14...sensor electrode, 16...protective layer, 18...adhesive layer, 100...touch sensor module, 110...operation panel, 112...operation surface, 120...frame member, 130...internal light source, 140...spring, θ...contact angle

Claims

1. A touch sensor module including an internal light source and a sensor sheet, The sensor sheet includes: A base layer provided at a position facing the internal light source; a sensor electrode disposed on one surface of the base layer; a protective layer disposed to cover the sensor electrode; a light diffusing layer disposed on a surface of the protective layer opposite to a surface on which the sensor electrode is disposed, The touch sensor module, wherein the light diffusion layer includes a plurality of lens structures containing an acrylic resin, and convex portions of the lens structures face toward the internal light source.

2. 2. The touch sensor module of claim 1, wherein the light diffusion layer contains a urethane acrylate UV-curable resin, and when the resin forming the light diffusion layer is formed into a predetermined test piece, the refractive index is 1.4 or more and 1.6 or less, and the total light transmittance is 90% or more.

3. The thickness of the light diffusion layer is 10 μm or more and 100 μm or less, the lens structure of the light diffusion layer is a substantially hemispherical lens shape or a substantially hemicylindrical structure, The diameter of the lens structure is 0.1 μm or more and 1.0 μm or less, The touch sensor module of claim 1 , wherein the ratio of the maximum height to the diameter of the lens structure is 0.05 or more and 0.1 or less.

4. The sensor sheet further includes an adhesive layer and an operation panel. When viewed from the internal light source side, the internal light source, the light diffusion layer, the protective layer, the sensor electrode, the base layer, the adhesive layer, and the operation panel are arranged in this order, The touch sensor module according to claim 1 , wherein the light diffusion layer and the protective layer are in direct contact with each other.

5. the light diffusion layer is disposed at a position overlapping with the internal light source when viewed from the operation panel side, The touch sensor module according to claim 4 , wherein a contour A of the lens structure is larger than a contour B of the sealing resin of the internal light source or a contour B of the lens, and the contour B is obscured by the contour A and cannot be seen.

6. 5. The touch sensor module of claim 4, wherein the light diffusion layer has a plurality of the lens structures spaced apart from each other, and the periphery of the area of ​​the light diffusion layer in which the plurality of lens structures are formed is smaller than the periphery of the area in which the internal light source illuminates the bottom surface of the light diffusion layer.

Images