Touch panel display device

Abstract

The present invention aims to provide a touch panel display device that exhibits excellent contrast between black and white displays when displaying in black and white, and also has excellent performance in suppressing contrast degradation in high-temperature and high-humidity environments. [Solution] The present invention provides a touch panel display device comprising a cover member, a first adhesive layer, a touch sensor, a second adhesive layer, and an organic electroluminescent display panel in this order, wherein the touch sensor has an acrylic substrate, the thickness of the acrylic substrate is 40 μm or less, and the thickness of the second adhesive layer is 100 μm or less.

Description

[Technical Field]

[0001] This invention relates to a touch panel display device. [Background technology]

[0002] Conventionally, various electronic devices, including tablet computers and smartphones, have used touch sensors to detect so-called touch operations, which occur when a finger or stylus pen is brought into contact with or close to the screen. Such touch sensors are typically formed on the surface of a substrate and have detection electrodes that detect touch operations.

[0003] For example, Patent Document 1 discloses a flexible electrode member for a touch panel having a transparent flexible substrate, a sensor electrode formed on at least one surface of the transparent flexible substrate, and an extraction circuit for electrically connecting to an external circuit; a touch panel equipped with the flexible electrode member for a touch panel; and an image display device in which the touch panel is placed on the display surface of an image display panel. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-116746 [Overview of the project] [Problems that the invention aims to solve]

[0005] In recent years, there has been an increase in the use of image display elements that offer high contrast in touch panel display devices, which include image display elements and touch sensors. Furthermore, there is a demand for touch panel display devices that suppress performance degradation under harsh conditions such as high temperature and high humidity environments. The inventors, referring to the technology disclosed in Patent Document 1, investigated the display performance of a touch panel display device combining a touch sensor and an organic electroluminescence (EL) display panel, and found that there is room for improvement in the contrast between black and white displays when displaying black and white simultaneously, and in the resistance of the touch panel display device to high temperature and high humidity environments.

[0006] In view of the above circumstances, the present invention aims to provide a touch panel display device that exhibits excellent contrast between black and white displays when displaying in black and white, and also has excellent performance in suppressing contrast degradation in high-temperature and high-humidity environments. [Means for solving the problem]

[0007] The inventors of this invention have diligently studied and developed the present invention to solve the above problems. Specifically, they have found that the above problems can be solved by the following configuration. [1] A touch panel display device comprising a cover member, a first adhesive layer, a touch sensor, a second adhesive layer, and an organic electroluminescent display panel in this order, wherein the touch sensor has an acrylic substrate, the thickness of the acrylic substrate is 40 μm or less, and the thickness of the second adhesive layer is 100 μm or less. [2] The touch panel display device according to [1], wherein the acrylic substrate contains polymethyl methacrylate. [3] The touch panel display device according to [1] or [2], wherein the thickness of the acrylic substrate is 35 μm or less. [4] A touch panel display device according to any one of [1] to [3], wherein the thickness of the second adhesive layer is 50 μm or less. [5] A touch panel display device according to any one of [1] to [4], wherein the sum of the thickness of the acrylic substrate and the thickness of the second adhesive layer is 56 μm or more. [6] The touch panel display device according to any one of [1] to [5], wherein the thickness of the second adhesive layer is 50 μm or less, and the total of the thickness of the acrylic base material and the thickness of the second adhesive layer is 56 μm or more. 〔7〕 The touch panel display device according to any one of [1] to [6], wherein the thickness of the first adhesive layer is 100 μm or less. 〔8〕 The touch panel display device according to any one of [1] to [7], wherein the relative permittivity of the second adhesive layer at a frequency of 100 kHz is 3.5 or less. 〔9〕 The touch panel display device according to any one of [1] to [8], wherein both the first adhesive layer and the second adhesive layer contain an acrylic resin. 〔10〕 The touch panel display device according to any one of [1] to [9], wherein the touch sensor has a detection electrode disposed on at least one surface of the acrylic base material, and the detection electrode has a mesh pattern formed by metal fine wires. 〔11〕 The touch panel display device according to

[10] , wherein the line width of the metal fine wire is 2.5 μm or less.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a touch panel display device that is excellent in the contrast between black display and white display in the case of black-and-white display, and is excellent in the performance of suppressing the contrast reduction in a high-temperature and high-humidity environment.

Brief Description of the Drawings

[0009] [Figure 1] It is a cross-sectional view schematically showing an example of the touch panel display device of the present invention. [Figure 2] It is a plan view showing an example of the detection electrode included in the touch sensor.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the touch panel display device of the present invention will be described in detail while referring to the drawings. The description of the constituent elements described below is based on typical embodiments of the present invention, and the present invention is not limited only to such embodiments. Also, each drawing is an example for explaining the present invention, and the scale of each component may be changed from the actual scale in order to facilitate visual recognition or explanation. In this specification, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. In this specification, when two or more kinds of a certain component are present, the "content" of that component means the total content of those two or more kinds of components. Regarding an angle, "orthogonal" or "perpendicular" means a range of 90° ± 5°, and "parallel" means a range of 0° ± 5°. Similarly, an angle represented by a specific numerical value means that the difference from the exact angle is within 5 degrees unless otherwise specified. The above orthogonal, perpendicular and parallel, and the difference between the above angle and the exact angle are preferably within 4 degrees, and more preferably within 3 degrees.

[0011] "Polymer", "macromolecule" or "polymer" each means a compound having a weight average molecular weight of 2000 or more. Here, the weight average molecular weight is defined as a polystyrene conversion value measured under the following conditions using gel permeation chromatography (GPC: Gel Permeation Chromatography). · Apparatus: HLC-8320GPC manufactured by Tosoh Corporation · Column: TSK-GEL G3000PWXL manufactured by Tosoh Corporation · Column temperature: 35°C · Flow rate: 0.5 mL / min · Calibration curve: POLY SODIUM ACRYLATE STANDARD manufactured by Sowa Kagaku Co., Ltd. · Eluent: A solution obtained by diluting a mixture of sodium dihydrogen phosphate dodecahydrate / disodium hydrogen phosphate dihydrate (34.5 g / 46.2 g) to 5000 g with pure water.

[0012] "Main surface" refers to the surface with the largest area in a film-like, sheet-like, or plate-like component. "Visible light" refers to light with wavelengths in the range of 380 to 780 nm. "Transparent" means that the light transmittance in the visible light wavelength range is 40% or more, preferably 60% or more, more preferably 80% or more, and even more preferably 90% or more. The light transmittance is measured using a known transmittance meter in accordance with "Plastics - Method for determining total light transmittance and total light reflectance" as specified in JIS K 7375:2008. In this specification, "acrylic resin" is used to mean either or both polymers and copolymers in which the content of units derived from at least one monomer ((meth)acrylate monomer) selected from the group consisting of acrylates and methacrylates is 50 mol% or more of the total units.

[0013] [Touch panel display device] The touch panel display device of the present invention comprises, in this order, a cover member, a first adhesive layer, a touch sensor, a second adhesive layer, and an organic electroluminescence (EL) display panel (hereinafter also referred to as "OLED panel"). The following will provide a detailed explanation of this display device, with reference to the diagrams.

[0014] Figure 1 is a schematic cross-sectional view showing an example of the touch panel display device of the present invention. In the touch panel display device 10 shown in Figure 1, the OLED panel 1, the second adhesive layer 2, the touch sensor 3, the first adhesive layer 4, and the cover member 5 are arranged in this order in the thickness direction. The touch sensor 3 comprises an acrylic substrate 30, a first detection electrode 31A consisting of a metal wire 31 disposed on one surface of the acrylic substrate 30, and a second detection electrode 32A consisting of a metal wire 32 disposed on the other surface of the acrylic substrate 30. As shown in the figure, the first adhesive layer 4 is arranged to cover the first detection electrode 31A consisting of the metal wire 31 on the surface 3a of the touch sensor 3, and the second adhesive layer 2 is arranged to cover the second detection electrode 32A consisting of the metal wire 32 on the surface 3b of the touch sensor 3. In the touch panel display device 10, the image displayed on the display surface 1a of the OLED panel 1 is visible through the second adhesive layer 2, the touch sensor 3, the first adhesive layer 4, and the cover member 5. The surface 5a of the cover member 5 opposite to the first adhesive layer 4 is the touch surface of the touch panel display device 10 and serves as the operating surface.

[0015] The touch panel display device of the present invention comprises a cover member, a first adhesive layer, a touch sensor, a second adhesive layer, and an organic electroluminescent display panel in this order, wherein the touch sensor has an acrylic substrate, the thickness of the acrylic substrate is 40 μm or less, and the thickness of the second adhesive layer is 100 μm or less.

[0016] The mechanism by which the touch panel display device of the present invention exhibits excellent contrast between black and white displays when displaying in black and white, and excellent performance in suppressing contrast degradation in high-temperature and high-humidity environments, is not entirely clear, but the inventors speculate as follows. The inventors of the present invention have diligently investigated the above-mentioned contrast reduction problem in touch panel display devices equipped with an OLED panel and a touch sensor. First, they found that even in a dark room without ambient light, an increase in the brightness of the black display was observed compared to the black display using only the OLED panel, indicating that the increase in the brightness of the black display and the decrease in contrast are not due to reflection of ambient light. Further investigation led them to hypothesize that the cause of the above is that, within the substrate of the touch sensor of the touch panel display device and within the adhesive layer placed between the touch sensor and the OLED panel, some of the light emitted from the white display area is transmitted or propagated by scattering or reflection, and travels toward the black display area adjacent to the white display area, reaching the position where the observer can see, resulting in an increase in the brightness of the black display. In contrast, the present inventors have found that the touch panel display device of the present invention uses a touch sensor having an acrylic substrate, and furthermore, by setting the thickness of the acrylic substrate and the second adhesive layer to below a predetermined range, the contrast between the black display and the white display when displaying black and white can be significantly improved. From the above estimated mechanism, it is estimated that, for example, because the thickness of the acrylic substrate and the adhesive layer is thin and the refractive index is close, reflection at the interface between the acrylic substrate and the adhesive layer is suppressed, the amount of light propagating inside the adhesive layer is reduced, and the increase in brightness of the black display displayed adjacent to the white display can be significantly suppressed, and as a result, the contrast between the black display and the white display can be improved. Furthermore, the inventors have found that depending on the type of substrate used in the touch sensor, the contrast between the black and white display may decrease in high-temperature and high-humidity environments. The touch panel display device of the present invention uses a touch sensor having an acrylic substrate, thereby suppressing the above-mentioned decrease in contrast in high-temperature and high-humidity environments.

[0017] Each component of the touch panel display device of the present invention will be described in more detail below. Hereinafter, the touch panel display device of the present invention will also be referred to as "this display device." Furthermore, in this specification, the phrase "the effects of the present invention are excellent" means that at least one of the following is excellent: the contrast between the black display and the white display when displaying in black and white on a touch panel display device (hereinafter also simply referred to as "contrast"), and the ability to suppress the decrease in contrast before and after storing the touch panel display device in a high-temperature, high-humidity environment (hereinafter also referred to as "humid heat environment resistance").

[0018] <Touch sensor> The touch sensor is a film that functions as a sensor for detecting touch operations, and has an acrylic substrate with a thickness of 40 μm or less. A specific example of a touch sensor is the touch sensor 3 shown in Figure 1, which has an acrylic substrate 1, a detection electrode 11 disposed on one surface of the acrylic substrate 1, and a detection electrode 12 disposed on the other surface of the acrylic substrate 1. The touch sensor is not limited to the configuration shown in Figure 1. For example, the sensing electrode may be located on only one surface of the acrylic substrate.

[0019] (Acrylic substrate) The acrylic substrate is a component that has the function of supporting the sensing electrode. Furthermore, the term "acrylic substrate" refers to a substrate whose main component is acrylic resin. The definition of acrylic resin is as described above. Furthermore, "primarily composed of acrylic resin" means that the acrylic resin content relative to the total mass of the substrate exceeds 50% by mass. The acrylic resin content is preferably 80% by mass or more, and more preferably 90% by mass or more, relative to the total mass of the acrylic substrate. There is no particular upper limit, and it may be 100% by mass.

[0020] Examples of acrylic resins that constitute the acrylic substrate include polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), sodium polyacrylate (PANa), polyacrylamide (PAAm), and polyacrylic acid ester (PAA). The acrylic substrate containing PMMA is more preferable from the viewpoint of the touch panel display device's resistance to humid and hot environments and touch panel sensitivity.

[0021] The acrylic substrate may further contain additives such as light stabilizers, antioxidants, ultraviolet absorbers, flame retardants, lubricants (fine particles), nucleating agents (crystallizing agents), and crystallization inhibitors, in addition to the acrylic resin. Furthermore, the acrylic substrate may further contain a visible light absorbing material.

[0022] An undercoat layer may be provided on at least one of the two main surfaces of the acrylic substrate. If an undercoat layer is provided, it is preferable to place the undercoat layer between the sensing electrode and the acrylic substrate. The undercoat layer may also be placed on both main surfaces of the acrylic substrate. Examples of materials constituting the undercoat layer include a binder resin and a surfactant. For example, the aforementioned acrylic resin can be used as the binder resin.

[0023] The thickness of the acrylic substrate is 40 μm or less, preferably 35 μm or less, and more preferably 31 μm or less, in terms of achieving superior effects of the present invention. Furthermore, in terms of achieving superior strength of the touch sensor and touch panel display device, the thickness of the acrylic substrate is more preferably 10 μm or more. Furthermore, when an acrylic substrate has a primer layer, the thickness of the acrylic substrate does not include the thickness of the primer layer. The thicknesses of the acrylic substrate, the first adhesive layer, and the second adhesive layer can be measured, for example, by observing a cross-section in the thickness direction using a scanning electron microscope (SEM) and taking the resulting image.

[0024] (Sensing electrode) The detection electrode is a component that functions as a sensor electrode for detecting touch operations. The sensing electrode is composed of, for example, multiple thin metal wires. Preferably, the touch sensor has a plurality of first detection electrodes 31A extending along a first in-plane direction on one surface of the acrylic substrate, and a plurality of second detection electrodes 32A extending along a second direction perpendicular to the first in-plane direction on the other surface of the acrylic substrate. The detection electrode may be placed on only one surface of the acrylic substrate. Alternatively, the first detection electrode 31A and the second detection electrode 32A may be laminated on only one surface of the acrylic substrate with an insulating layer in between.

[0025] The detection electrode may have a predetermined pattern formed by metal nanowires. The pattern formed is not particularly limited, but it is preferably a mesh-like (mesh pattern). A mesh-like shape means a shape that includes multiple openings (grids) made up of intersecting metal nanowires, as shown in Figure 2. The detection electrode preferably has a mesh pattern formed by metal nanowires. Figure 2 is a plan view showing an example of the configuration of the first detection electrode 31A of the touch sensor. In the first detection electrode 31A of the touch sensor shown in Figure 2, the shape of the opening 33 is a mesh pattern in which a square with side length L is formed by metal thin wires 31.

[0026] The mesh pattern of the sensing electrode can be a combination of geometric shapes such as equilateral triangles, isosceles triangles, right triangles, quadrilaterals such as squares, rectangles, rhombuses, parallelograms, and trapezoids, regular n-gons such as regular hexagons and regular octagons, circles, ellipses, and stars. The shape of one side of the opening can be straight, curved, or arc-shaped. If it is arc-shaped, for example, two opposing sides may be outwardly convex arcs, and the other two opposing sides may be inwardly convex arcs. Alternatively, the shape of each side may be a wavy line shape consisting of a continuous outwardly convex arc and an inwardly convex arc. Of course, the shape of each side may also be a sine curve. The mesh pattern is not particularly limited and may be random or regular, or a regular mesh pattern in which multiple congruent shapes are repeatedly arranged.

[0027] As for the mesh pattern of the sensing electrode, a regular mesh pattern with rhombus-shaped openings of the same shape is preferable in terms of reducing interference patterns (moire) with the pixel pattern of the display panel. The preferred acute angle of the rhombus is 20 to 70 degrees. The length L of one side of the opening is preferably 100 to 1000 μm, and more preferably 150 to 600 μm, in terms of visibility. When the length of one side of the opening is within the above range, good transparency can be maintained, and the displayed image can be viewed without discomfort in this display device. The aperture ratio of the mesh pattern of the sensing electrode is preferably 90% or higher, and more preferably 95% or higher, in terms of visible light transmittance. There is no particular upper limit, but it is less than 100%. The aperture ratio corresponds to the area ratio of the openings, excluding the metal wires, to the total area of ​​the region where the sensing electrode is provided. Furthermore, the mesh pattern of the detection electrode can be observed and measured using an optical microscope.

[0028] The wire width of the metal nanowire constituting the sensing electrode is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 2.5 μm or less, in terms of superior visibility. The lower limit is not particularly limited, but in terms of superior conductivity of the metal nanowire, it is preferably 1.0 μm or more, and more preferably 1.5 μm or more. Furthermore, the height of the metal wire is not particularly limited, but is, for example, 0.1 to 10 μm, and preferably 0.3 to 5 μm. The line width and height of the above-mentioned metal nanowires are obtained by selecting five arbitrary metal nanowires using a scanning electron microscope and taking the arithmetic mean of the values ​​corresponding to the measured line width and height.

[0029] Metal wires contain metal. As for the metal, silver (metallic silver), copper (metallic copper), gold (metallic gold), nickel (metallic nickel), palladium (metallic palladium), or mixtures of two or more of these are preferred in terms of superior conductivity, silver, copper, or mixtures thereof are more preferred, and copper is even more preferred. The form of the metal in the metal nanowire is not limited; for example, it can be in particulate form or in a layered form dispersed within the metal nanowire.

[0030] The metal nanowire may be a metal nanowire containing metallic silver, which is suitable for forming a mesh pattern, and a polymer binder such as gelatin and acrylic-styrene latex. When the metal nanowire contains a polymer binder, the metal particles may be dispersed within the polymer, or they may aggregate within the polymer to form aggregates. The type of polymer is not particularly limited, and known polymers can be used. The metal wire may be composed of aluminum, copper, silver, molybdenum, and titanium, or their alloys. Alternatively, it may have a laminated structure; for example, metal wires with a laminated structure such as molybdenum / copper / molybdenum or molybdenum / aluminum / molybdenum can be used.

[0031] Other components besides the sensing electrode may be placed on the surface of the acrylic substrate. Other components include, for example, an electrode connection terminal formed at one end of the sensing electrode, peripheral wiring electrically connected to the electrode connection terminal, and an external connection terminal electrically connected to the peripheral wiring and external equipment. These components have the function of transmitting the electrical signal detected by the sensing electrode to the external equipment. Furthermore, dummy electrodes may be placed on the surface of the acrylic substrate as other components. The dummy electrodes are placed between the sensing electrodes. Preferably, the dummy electrodes are made of thin metal wires, similar to the sensing electrodes.

[0032] (Manufacturing method for touch sensors) The method for manufacturing the touch sensor is not particularly limited as long as it can form the above-mentioned detection electrode on at least one surface of an acrylic substrate. Suitable methods for forming the detection electrode include, for example, sputtering, plating, silver halide, and printing.

[0033] A method for forming a detection electrode by sputtering will be described. First, a copper foil layer can be formed by sputtering, and then copper wiring can be formed from the copper foil layer by photolithography to form the detection electrode. Alternatively, the copper foil layer can be formed by vapor deposition instead of sputtering. In addition to sputtered copper foil or vapor-deposited copper foil, electrolytic copper foil can also be used for the copper foil layer. More specifically, the process for forming copper wiring described in Japanese Patent Publication No. 2014-029614 can be used.

[0034] A method for forming a detection electrode by plating will be described. For example, a metal plating film is formed on an electroless plating substrate by applying electroless plating to the substrate. This metal plating film can be used as a detection electrode. In this case, the detection electrode is formed by first forming a pattern on an acrylic substrate using a catalyst ink containing at least metal fine particles, and then immersing the acrylic substrate in an electroless plating bath to form a metal plating film. More specifically, the method for manufacturing a metal-coated substrate described in Japanese Patent Application Publication No. 2014-159620 can be used.

[0035] Furthermore, the detection electrode is formed by first forming a pattern on an acrylic substrate of a resin composition having functional groups that can interact with at least a metal catalyst precursor, then applying a catalyst or catalyst precursor, and finally immersing the acrylic substrate in an electroless plating bath to form a metal plating film. More specifically, the method for manufacturing a metal coating substrate described in Japanese Patent Application Publication No. 2012-144761 can be applied.

[0036] A method for forming a detection electrode using the silver halide method will be described. First, a silver halide emulsion layer containing silver halide is exposed using an exposure pattern corresponding to the detection electrode pattern, and then a development process is performed to form the detection electrode. More specifically, the method for manufacturing metal nanowires described in Japanese Patent Publication No. 2012-006377, Japanese Patent Publication No. 2014-112512, Japanese Patent Publication No. 2014-209332, Japanese Patent Publication No. 2015-022397, Japanese Patent Publication No. 2016-192200 and International Publication No. 2016 / 157585 can be used.

[0037] A method for forming a detection electrode by printing will be described. First, a conductive paste containing conductive powder is applied to a substrate in the same pattern as the detection electrode, and then the detection electrode can be formed by heat treatment. Pattern formation using the conductive paste can be done, for example, by an inkjet method or a screen printing method. More specifically, the conductive paste described in Japanese Patent Application Publication No. 2011-028985 can be used as the conductive paste.

[0038] <Second adhesive layer> The second adhesive layer is placed between the touch sensor and the OLED panel and has the function of fixing the touch sensor and the OLED panel together. Its thickness is 100 μm or less. The components of the second adhesive layer are not particularly limited as long as they are components that perform the above-mentioned functions. The second adhesive layer is preferably transparent and electrically insulating.

[0039] The second adhesive layer preferably contains an adhesive. Examples of adhesives used in the second adhesive layer include optically clear adhesives (OCA) and optically clear resins (OCR), such as UV (Ultra Violet) curing resins. Examples of OCA and OCR include acrylic resins, urethane acrylate resins, urethane resins, rubber-based resins, epoxy resins, epoxy acrylate resins, oxetane resins, silicone resins, silicone acrylic resins, polyester resins, polyether resins (such as polyvinyl ether), polyamide resins, fluororesins, vinyl acetate / vinyl chloride copolymers, and modified polyolefins. One or more of the above resins may be used. Among these, acrylic resin is preferred in terms of superior effects of the present invention, as well as weather resistance and cost.

[0040] The content of the adhesive (more preferably acrylic resin) in the second adhesive layer is preferably 85% by mass or more, and more preferably 90% by mass or more, based on the total mass of the second adhesive layer. The upper limit is not particularly limited and may be, for example, 99% by mass or less. The content of the adhesive in the second adhesive layer may be the remainder of the visible light absorber and any additives. The second adhesive layer may optionally contain additives, provided that they do not impair its function as an adhesive layer or the effects of the present invention. Examples of additives include crosslinking agents, ultraviolet absorbers, plasticizers, antistatic agents, and corrosion inhibitors.

[0041] The thickness of the second adhesive layer is 100 μm or less, preferably 75 μm or less, more preferably 50 μm or less, in terms of superior effects of the present invention, and preferably 5 μm or more, more preferably 25 μm or more, and even more preferably 50 μm or more, in terms of superior effects of the present invention and touch panel sensitivity. When the thickness of the second adhesive layer is greater than or equal to the above lower limit, it is presumed that touch panel sensitivity will be improved because malfunctions of the touch sensor due to noise signals flowing through the OLED panel are suppressed.

[0042] In this display device, the sum of the thickness of the acrylic substrate and the thickness of the second adhesive layer is, for example, 35 μm or more, preferably 56 μm or more, and more preferably 80 μm or more, in terms of achieving superior effects of the present invention. Furthermore, the sum of the thickness of the acrylic substrate and the thickness of the second adhesive layer is 140 μm or less, preferably 100 μm or less, and more preferably 90 μm or less.

[0043] The relative permittivity of the second adhesive layer at a frequency of 100 kHz is preferably 4.0 or less, more preferably 3.5 or less, and even more preferably 3.0 or less. The lower limit is not particularly limited and may be, for example, 2.0 or more. If the dielectric constant of the second adhesive layer is below the above upper limit, the performance in blocking the effects of electromagnetic noise from the OLED panel will be better. The dielectric constant is determined in accordance with JIS K 6911:2006.

[0044] Various known methods can be applied to form the second adhesive layer. Methods for forming the second adhesive layer include, for example, a method of forming the second adhesive layer by applying an adhesive composition containing the above-mentioned resin to the surface of the touch sensor (application method), and a method of forming the second adhesive layer on a temporary support using the above-mentioned adhesive composition, and then transferring the second adhesive layer to the surface on which the detection electrodes of the touch sensor are placed (transfer method). Among these methods, the transfer method is preferred because it allows for the production and inspection of the touch sensor and the second adhesive layer individually, and the yield of touch panel display devices can be increased by using only the good products. The adhesive composition coating film formed on the surface of the touch sensor or temporary support may be dried as needed. Both the method for applying the adhesive composition and the drying treatment of the coating film can be performed using known methods.

[0045] The adhesive composition used to form the adhesive layer may further contain the above-mentioned additives in addition to the adhesive. Furthermore, the adhesive composition may further contain coating aids such as solvents, surfactants, and thickeners. The adhesive composition preferably further contains a solvent. Examples of solvents include water and organic solvents, and a solvent capable of dissolving or dispersing components such as the adhesive and visible light absorber is appropriately selected. If the adhesive composition contains a solvent, the solid content concentration of the adhesive composition is preferably 5 to 60% by mass, and more preferably 10 to 50% by mass. The "solid content" of the adhesive composition refers to the components that constitute the adhesive layer formed using the adhesive composition, and if the adhesive composition contains a solvent, it refers to all components excluding the solvent. Liquid components that form the adhesive layer are also considered solid content.

[0046] <1st adhesive layer> The first adhesive layer is positioned between the cover member and the touch sensor and has the function of fixing the cover member and the touch sensor together. The components and thickness of the first adhesive layer are not particularly limited as long as they are components that perform the above-mentioned functions. The first adhesive layer is preferably transparent and electrically insulating.

[0047] The thickness of the first adhesive layer is, for example, 250 μm or less, preferably 125 μm or less, and more preferably 100 μm or less, in terms of achieving superior effects of the present invention. The lower limit of the thickness of the first adhesive layer is not particularly limited, but it is preferably 5 μm or more, and 75 μm or more is preferable in that it provides better adhesion between the cover member and the touch sensor. In this display device, the total thickness of the acrylic substrate, the first adhesive layer, and the second adhesive layer is, for example, 136 to 265 μm, with 150 to 200 μm being preferred for superior contrast and resistance to humid and hot environments.

[0048] The constituent components and relative permittivity of the first adhesive layer may be the same as those of the second adhesive layer, but it is preferable that at least one of the constituent components and relative permittivity be different. In particular, it is preferable that the relative permittivity of the second adhesive layer be lower than that of the first adhesive layer, as this improves the sensitivity of the touch panel. The preferred relative permittivity of the first adhesive layer at a frequency of 100 kHz is 3.5 or higher, more preferably 4.0 or higher, and the difference between the relative permittivity of the first adhesive layer and the relative permittivity of the second adhesive layer ((relative permittivity of the first adhesive layer at a frequency of 100 kHz) - (relative permittivity of the second adhesive layer at a frequency of 100 kHz)) being 1.0 or higher is preferable in terms of improving the sensitivity of the touch panel. Furthermore, it is preferable that the first adhesive layer and the second adhesive layer contain the same type of adhesive, and it is preferable that both the first adhesive layer and the second adhesive layer contain acrylic resin in order to achieve superior effects of the present invention. Furthermore, it is preferable that the thickness of the first adhesive layer is greater than the thickness of the second adhesive layer, as this enhances the effects of the present invention. It is also preferable that the thickness of the first adhesive layer is greater than the thickness of the acrylic substrate, as this increases the strength of the touch panel display device.

[0049] <OLEDパネル> The OLED panel used in this display device is not particularly limited as long as it is a display panel that uses organic EL elements. This display device, equipped with an OLED panel and a touch sensor, can be used as a touch panel display device with touch detection capabilities. Furthermore, by incorporating an OLED panel, the overall thickness of this display device can be reduced while providing image quality with superior contrast.

[0050] <Cover component> This touch panel display device has a cover member on the viewing side of the touch sensor. In the touch panel display device 10 shown in Figure 1, the visible surface 5a of the cover member 5 is both the touch surface and the operating surface of the touch panel display device 10. That is, the visible surface 5a of the cover member 5 is used as the operating surface for input operations. The touch surface refers to the surface that detects contact with a finger or stylus pen, etc. Since the surface of the cover member will be a touch surface, a hard coat layer may be provided on the surface as needed. Furthermore, it is preferable to apply treatments to the surface of the cover member to impart various functions such as scratch prevention, anti-glare treatment, anti-fouling treatment, anti-fogging treatment, and anti-reflective treatment.

[0051] The structure of the cover member is not particularly limited, but it is preferable that it be transparent so that the image displayed on the display surface of the OLED panel can be viewed. Examples of cover members include transparent glass substrates such as chemically strengthened glass, sapphire substrates, and transparent plastic substrates such as PMMA, PET, and polycarbonate. The cover component, which is a transparent glass substrate, is also called a cover lens or cover glass.

[0052] The refractive index of the cover member is preferably 1.40 to 1.70. The difference in refractive index between the cover member and other members is preferably 0.1 or less. The thickness of the cover material should preferably be selected appropriately according to its intended use. In the cover member, a decorative layer made of black ink or the like may be provided in the non-display area where the image of the OLED panel is not displayed.

[0053] The present invention is basically configured as described above. The present invention is not limited to the above embodiments, and various improvements or modifications may be made without departing from the spirit of the invention. [Examples]

[0054] The present invention will be described in more detail below based on examples. The materials, quantities, proportions, processing details, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples.

[0055] [Example 1] A 40 μm thick PMMA film was prepared as the acrylic substrate. A detection electrode having a mesh pattern composed of metal fine wires was fabricated on both sides of the above PMMA film in accordance with the method described in Step 1 of Example 1 of International Publication No. 2022 / 071273. Specifically, a conductive layer consisting of a copper oxynitride film (blackened layer), a copper film, and a copper oxynitride film (blackened layer) was first formed on both sides of the above PMMA film by sputtering. The thicknesses of the copper oxynitride film, copper film, and copper oxynitride film were 38 nm, 500 nm, and 38 nm, respectively. Next, the conductive layer was patterned using photolithography. More specifically, a resist film was formed on the surface of the conductive layer, the conductive layer was exposed with a photomask placed on the resist film, and the exposed resist film was developed to obtain a resist film having a pattern corresponding to the photomask. Using this resist film as a mask, the conductive layer was etched with an etching solution, and then the resist film was peeled off to manufacture a touch sensor 1 on both sides of the PMMA film, which had a detection electrode consisting of a regular mesh pattern, an electrode connection terminal formed at the end of the detection electrode, a lead wire connected to the electrode connection terminal, and an external connection terminal connected to the lead wire. The mesh pattern of the detection electrode of the touch sensor 1 consisted of rhombus-shaped mesh cells (acute angle of 60 degrees, side length of 500 μm) made of fine metal wires with a line width of 2.5 μm arranged in a row.

[0056] A cover member 5 made of chemically strengthened glass with a thickness of 0.4 mm was bonded to one main surface of the touch sensor 1 via an OCA 1 (3M "8146-5", first adhesive layer) made of acrylic resin with a thickness of 125 μm. Next, an OLED panel (Samsung Display Co., Ltd., model number "ATNA40CU03") was bonded to the other main surface of the touch sensor 1 via an OCA (Shin Tack Chemical Co., Ltd. "SA364GF", second adhesive layer) made of acrylic resin with a thickness of 100 μm. In this way, a touch panel display device of Example 1 was fabricated, comprising the OLED panel, second adhesive layer, touch sensor, first adhesive layer, and cover member in this order. Furthermore, a flexible printed circuit board (FPC) for connecting to a touch driver IC (integrated circuit) was pre-connected to the external connection terminal of the touch sensor 1 via an anisotropic conductive film.

[0057] [Examples 2-11, Comparative Examples 1-6] Touch panel display devices of Examples 2 to 11 and Comparative Examples 1 to 6 were fabricated as described below, using the acrylic substrate, the first adhesive layer, and the second adhesive layer, respectively, with the materials listed in Table 1 below. The touch panel display device of Example 2 was fabricated in the same manner as in Example 1, except that the acrylic substrate of Example 1 was changed to a PMMA film with a thickness of 31 μm. The touch panel display device of Example 3 was manufactured in the same manner as in Example 1, except that the second adhesive layer of Example 1 was changed to OCA (SA362GF, manufactured by Shin-Tack Kasei Co., Ltd.), which is made of acrylic resin with a thickness of 50 μm. The touch panel display device of Example 4 was manufactured in the same manner as in Example 1, except that the first adhesive layer of Example 1 was changed to OCA (3M "8146-4") made of acrylic resin with a thickness of 100 μm. The touch panel display device of Example 5 was manufactured in the same manner as in Example 4, except that the second adhesive layer of Example 4 was changed to OCA (SA362GF, manufactured by Shin-Tack Kasei Co., Ltd.) made of acrylic resin with a thickness of 50 μm. The touch panel display device of Example 6 was fabricated in the same manner as in Example 5, except that the acrylic substrate of Example 5 was changed to a PMMA film with a thickness of 31 μm. The touch panel display device of Example 7 was manufactured in the same manner as in Example 4, except that the second adhesive layer of Example 4 was changed to OCA (SA361GF, manufactured by Shin-Tack Kasei Co., Ltd.), which is made of acrylic resin with a thickness of 25 μm. The touch panel display device of Example 8 was fabricated in the same manner as in Example 7, except that the acrylic substrate of Example 7 was changed to a PMMA film with a thickness of 31 μm. The touch panel display device of Example 9 was manufactured in the same manner as in Example 4, except that the second adhesive layer of Example 4 was changed to OCA (NCF-F619, manufactured by Lintec Corporation) made of acrylic resin with a thickness of 5 μm. The touch panel display device of Example 10 was fabricated in the same manner as in Example 9, except that the acrylic substrate of Example 9 was changed to a PMMA film with a thickness of 31 μm. The touch panel display device of Example 11 was fabricated in the same manner as in Example 1, except that the acrylic substrate of Example 1 was changed to a 40 μm thick PAN (polyacrylonitrile) film.

[0058] A touch panel display device for Comparative Example 1 was manufactured in the same manner as in Example 1, except that the acrylic substrate in Example 1 was changed to a PMMA film with a thickness of 50 μm, and the second adhesive layer was changed to OCA (SA366GF, manufactured by Shin-Tack Chemical Co., Ltd.) made of acrylic resin with a thickness of 125 μm. A touch panel display device of Comparative Example 2 was manufactured in the same manner as in Example 1, except that the second adhesive layer of Example 1 was changed to OCA (SA366GF, manufactured by Shin-Tack Kasei Co., Ltd.), which is made of acrylic resin with a thickness of 125 μm. A touch panel display device for Comparative Example 3 was fabricated in the same manner as in Example 1, except that the acrylic substrate in Example 1 was changed to a PMMA film with a thickness of 50 μm. A touch panel display device for Comparative Example 4 was fabricated in the same manner as in Example 5, except that the acrylic substrate in Example 5 was changed to a PMMA film with a thickness of 50 μm. A touch panel display device for Comparative Example 5 was fabricated in the same manner as in Example 5, except that the acrylic substrate in Example 5 was changed to a polyethylene terephthalate (PET) film with a thickness of 38 μm. Furthermore, a touch panel display device for Comparative Example 6 was fabricated in the same manner as in Example 5, except that the acrylic substrate in Example 5 was changed to a 40 μm thick triacetylcellulose (TAC) film.

[0059] The relative permittivity of the first and second adhesive layers of the touch panel display devices of Examples 1 to 11 was measured at a frequency of 100 kHz. The results showed that the relative permittivity of the first adhesive layer in each example was 4.1, the relative permittivity of the second adhesive layer in Examples 1 to 8 and 11 was 2.9, and the relative dielectric constant of the second adhesive layer in Examples 9 and 10 was 4.8.

[0060] [evaluation] (1) Contrast In a darkroom without windows, a touch panel display device was installed with its display surface facing vertically upwards. A white square image measuring 80mm x 80mm (R, G, B = 255, 255, 255) was displayed in the center of the touch panel display device's screen, and a black image (R, G, B = 0, 0, 0) was displayed around the entire perimeter of the white image. A cylinder (60mm in diameter, 350mm in length) made by rolling up black cardboard was placed vertically on the white display area of ​​the touch panel display device, with the cylinder's central axis approximately aligned with the center of the white display area, and the cylinder was positioned perpendicular to the display surface. A spectroradiometer (Konica Minolta CS-3000HDR) was set on the end of the cylinder, and the brightness of the image displayed by the touch panel display device was measured under the following measurement conditions. Subsequently, the brightness of the measured white display area was approximately 500 cd / m². 2 The output brightness of the touch panel display device is adjusted to achieve the following, and the measured brightness of the white display area is set to L W That's what I decided. (Luminance meter measurement conditions) • Speed ​​mode: FAST • Dark setting: Standard • Aperture angle: 1 degree

[0061] Next, while maintaining the output luminance of the touch panel display device (luminance of the white display portion), the positions of the black display portion and the white display portion of the touch panel display device were switched (a square image of black ((R, G, B) = (0, 0, 0)) with a size of 80 mm × 80 mm was displayed at the center of the screen, and an image of white ((R, G, B) = (255, 255, 255)) was displayed over the entire periphery of the black display image). The cylinder was vertically erected so that the center of the black display image and the central axis of the cylinder were substantially coincident, and the luminance was measured using a spectro-radiance meter under the above measurement conditions. The luminance of the measured black display portion was designated as L B and this was used as the value. The luminance L of the black display portion obtained above B and the luminance L of the white display portion with respect to L W The ratio (L W / L B ) was calculated as the contrast ratio. Based on the following criteria, the contrast between the black display and the white display when performing black and white display for each touch panel display device was evaluated from the calculated contrast ratio.

[0062] -Contrast Evaluation Criteria- "AA": The contrast ratio is 2.5 million or more. "A": The contrast ratio is 2 million or more and less than 2.5 million. "B": The contrast ratio is 1.25 million or more and less than 2 million. "C": The contrast ratio is 1 million or more and less than 1.25 million. "D": The contrast ratio is less than 1 million.

[0063] (2) Humid Heat Environment Resistance A humid heat test was conducted in which the touch panel display device was stored in an environment of a temperature of 60°C and a humidity of 90%RH for 48 hours, and the contrast ratio of the touch panel display device after the humid heat test was determined in the same manner as in (1) above. The contrast ratio C B before the humid heat test and the contrast ratio C A after the humid heat test were used to define the value calculated by the formula (C B / C A ) as the contrast ratio degradation rate. Based on the contrast ratio degradation rate obtained for each example of touch panel display device, the resistance of each touch panel display device to humid and hot environments was evaluated according to the following criteria.

[0064] - Evaluation Criteria for Resistance to Humid Heat Environments - "A": Contrast ratio degradation rate is less than 2. "B": Contrast ratio degradation rate is between 2 and 5. "C": Contrast ratio degradation rate is between 2 and 10. "D": Contrast ratio degradation rate of 10 or more.

[0065] (3) Touch panel sensitivity A white image ((R, G, B)=(255, 255, 255)) is displayed across the entire surface of the touch panel display device, with a brightness of 500 cd / m². 2 I adjusted it to that. A stylus pen with a tip diameter of 2 mm was placed in contact with the touch surface (exposed surface) of the cover glass, and the cursor's movement response on the OLED panel was visually observed when the stylus pen was moved along the diagonal of the displayed white image from one vertex to the other. Based on the observation results of the cursor's movement response in response to the stylus pen's movement, the touch panel sensitivity of each touch panel display device was evaluated based on the following criteria.

[0066] - Evaluation Criteria for Touch Panel Sensitivity - "A": The cursor moves without any lag, even when the stylus pen is moved at high speed. "B": The cursor functions without practical problems even when the stylus pen is moved at high speed. "C": The cursor only works without practical problems when the stylus pen is moved slowly. "D": There is a discrepancy between the stylus pen position and the cursor position.

[0067] Table 1 shows the configuration of the touch panel display device for each example, as well as the evaluation results for each example.

[0068] [Table 1]

[0069] From the results in Table 1, it was confirmed that the touch panel display devices of the present invention in Examples 1 to 11 exhibit excellent contrast between black and white displays when displaying in black and white, and also have excellent performance in suppressing contrast degradation in high-temperature and high-humidity environments. In contrast, the touch panel display devices of Comparative Examples 1 to 4, in which the thickness of the acrylic substrate exceeded 40 μm or the thickness of the second adhesive layer exceeded 100 μm, showed insufficient improvement in contrast. Furthermore, in Comparative Example 5, the touch panel display device in which the touch sensor's substrate was made of PET, the contrast improvement was insufficient, and in Comparative Example 6, the touch panel display device in which the touch sensor's substrate was made of TAC, the performance in suppressing contrast degradation under high temperature and high humidity conditions was insufficient.

[0070] From a comparison of Examples 1 and 2, and a comparison of Examples 5 and 6, it was confirmed that when the thickness of the acrylic substrate is 35 μm or less, the contrast between the black and white display is better. From a comparison of Examples 1 and 3, and a comparison of Examples 4 and 5, it was confirmed that when the thickness of the second adhesive layer is 50 μm or less, the contrast between the black and white display is better. From a comparison of Examples 1 and 4, and a comparison of Examples 3 and 5, it was confirmed that when the thickness of the first adhesive layer is 100 μm or less, the contrast between the black and white display is better. From a comparison of Examples 7 and 9, and a comparison of Examples 8 and 10, it was confirmed that when the thickness of the second adhesive layer is 25 μm or more, the performance in suppressing contrast degradation under high temperature and high humidity conditions is superior. From a comparison of Examples 5, 7, and 9, and a comparison of Examples 6, 8, and 10, it was confirmed that when the sum of the thickness of the acrylic substrate and the thickness of the second adhesive layer is 56 μm or more, the touch panel sensitivity is superior, and when the sum of the thickness of the acrylic substrate and the thickness of the second adhesive layer is 80 μm or more, the touch panel sensitivity is even superior. Furthermore, a comparison between Examples 1 and 11 confirmed that among acrylic substrates, PMMA film provided superior heat resistance and touch panel sensitivity compared to PAN film. [Explanation of Symbols]

[0071] 1: OLED panel 1a:Display surface 2:Second adhesive layer 3: Touch sensor 3a,3b,5a:Surface 4: 1st adhesive layer 5: Cover component 10: Touch panel display device 30: Acrylic substrate 31,32: Fine metal wire 31A: First detection electrode 32A: Second detection electrode 33: Opening

Claims

1. A touch panel display device comprising a cover member, a first adhesive layer, a touch sensor, a second adhesive layer, and an organic electroluminescent display panel in this order, The touch sensor has an acrylic substrate, The thickness of the acrylic substrate is 40 μm or less. A touch panel display device in which the thickness of the second adhesive layer is 100 μm or less.

2. The touch panel display device according to claim 1, wherein the acrylic substrate contains polymethyl methacrylate.

3. The touch panel display device according to claim 1 or 2, wherein the thickness of the acrylic substrate is 35 μm or less.

4. The touch panel display device according to claim 1 or 2, wherein the thickness of the second adhesive layer is 50 μm or less.

5. The touch panel display device according to claim 1 or 2, wherein the sum of the thickness of the acrylic substrate and the thickness of the second adhesive layer is 56 μm or more.

6. The thickness of the second adhesive layer is 50 μm or less. The touch panel display device according to claim 1 or 2, wherein the sum of the thickness of the acrylic substrate and the thickness of the second adhesive layer is 56 μm or more.

7. The touch panel display device according to claim 1 or 2, wherein the thickness of the first adhesive layer is 100 μm or less.

8. The touch panel display device according to claim 1 or 2, wherein the relative permittivity of the second adhesive layer at a frequency of 100 kHz is 3.5 or less.

9. The touch panel display device according to claim 1 or 2, wherein both the first adhesive layer and the second adhesive layer contain an acrylic resin.

10. The touch sensor has a detection electrode located on at least one surface of the acrylic substrate. The touch panel display device according to claim 1 or 2, wherein the detection electrode has a mesh pattern formed of metal fine wires.

11. The touch panel display device according to claim 10, wherein the line width of the metal fine wire is 2.5 μm or less.

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