TW201823952A - Touch sensor laminate and method of manufacturing the same - Google Patents

Abstract

A touch sensor laminate includes a touch sensor layer, a second adhesive layer, a first adhesive layer, a release film, and an optical film. The second adhesive layer is formed on an upper surface of the touch sensor layer. The first adhesive layer is formed on the lower surface of the touch sensor layer. The peel strength of the first adhesive layer is less than the peel strength of the second adhesive layer. The release film is adhered to the lower surface of the first adhesive layer. The optical film is adhered to the upper surface of the second adhesive layer.

Description

Touch sensor laminate and method of manufacturing same

The present invention relates to a touch sensor laminate and a method of fabricating the same, and more particularly to a touch sensor laminate including a plurality of electrode patterns and a method of fabricating the same.

With the development of information technology, various demands for display devices having a small size, light weight, and high power consumption efficiency are increasing. The display device may include a flat panel display device such as a liquid crystal display (LCD) device, a plasma display panel (PDP) device, an electroluminescence display device, an organic light emitting diode display (OLED) device, or the like. In addition, touch sensors are combined with display devices to enable image display and information input in a single electronic device.

As the display device is thinned, flexible performance including bending or folding performance can be achieved in the display device. Therefore, there is a need to develop a touch sensor that can be used in a flexible display device.

For example, in the manufacture of a touch sensor, an electrode pattern or a wiring pattern may be formed on a carrier substrate, and a substrate layer may be formed to cover the electrode pattern or the wiring pattern. Subsequently, the carrier substrate can be separated. In this case, a functional layer such as a sacrificial layer or a separation layer may be further formed to promote separation of the carrier substrate.

Referring to Korean Patent No. 1191865, a sacrificial layer, a metal wiring, and a flexible substrate which can be removed by a solvent are sequentially formed on a carrier substrate, and then the sacrificial layer is removed together with the carrier substrate.

However, the above method may not be easily performed in the manufacture of large-scale displays, and the metal wiring may be damaged by the solvent. In addition, stress from the separation process may be applied to the metal wiring or the touch sensor, causing damage thereto.

According to one aspect of the invention, a touch sensor laminate having improved mechanical reliability and flexibility properties is provided.

According to one aspect of the invention, a method of fabricating a touch sensor stack having improved mechanical reliability and flexibility properties is provided.

According to an aspect of the invention, a flexible display device including a touch sensor laminate is provided.

The above aspects of the invention will be realized by the following features:

(1) A touch sensor laminate comprising: a touch sensor layer; a second adhesive layer formed on an upper surface of the touch sensor layer; a first adhesive layer formed on the touch sensing On the lower surface of the layer, the peel strength of the first adhesive layer is less than the peel strength of the second adhesive layer; the release film adheres to the lower surface of the first adhesive layer; and the optical film adheres to the second On the upper surface of the adhesive layer.

(2) The touch sensor laminate according to the above (1), wherein the first adhesive layer has a peel strength of 0.2 N/25 mm or less, and the second adhesive layer has a peel strength of 0.2 N/25 mm to 20N/25mm range.

(3) The touch sensor laminate according to (1) above, wherein the second adhesive layer comprises a material, and the peel strength of the material is lowered by light irradiation.

(4) The touch sensor laminate according to (3) above, wherein the second adhesive layer has a peel strength before light irradiation in a range of 0.2 N/25 mm to 20 N/25 mm, and the second adhesive The peel strength of the layer after light irradiation was 0.2 N/25 mm or less.

(5) The touch sensor layered body according to (1) above, wherein the touch sensor layer includes a multilayer structure including an electrode pattern.

(6) The touch sensor layered body according to the above (5), wherein the touch sensor layer includes an intermediate layer including an organic polymer, an electrode pattern layer, and an upper protective layer which are sequentially stacked from the first adhesive layer .

(7) The touch sensor laminate according to (6) above, wherein the intermediate layer includes a separation layer and a lower protective layer which are sequentially stacked from the first adhesive layer.

(8) The touch sensor laminate according to (1) above, wherein the optical film comprises a protective film formed of a polymer.

(9) The touch sensor laminate according to (1) above, wherein the second adhesive layer and the optical film are formed on a touch surface of the touch sensor layer.

(10) A method of manufacturing a touch sensor laminate comprising: sequentially forming a touch sensor layer, a second adhesive layer, and an optical film on a carrier substrate; separating the carrier substrate from the touch sensor layer; Forming a first adhesive layer on a lower surface of the touch sensor layer from which the carrier substrate is removed, the peel strength of the first adhesive layer is less than the peel strength of the second adhesive layer; and attaching the release film to the first The lower surface of the adhesive layer.

(11) The method according to (10) above, further comprising: separating the release film from the first adhesive layer; adhering the base film to the lower surface of the first adhesive layer from which the release film is removed; and removing Optical film.

(12) The method according to the above (11), wherein the removing the optical film comprises: reducing the peel strength of the second adhesive layer by irradiating the optical film with light.

(13) The method according to (12) above, wherein the substrate film comprises a material that does not transmit ultraviolet rays.

(14) The method according to (10) above, further comprising: curing the first adhesive layer by irradiating light to the release film; removing the release film; and using the cured first adhesive layer as a substrate to remove Optical film.

(15) A touch sensor laminate comprising: a photocurable organic layer and a touch sensor layer on the photocured organic layer.

(16) The touch sensor laminate according to (15) above, wherein the photocurable organic layer comprises a binder layer, a dry film or a dry film resist.

(17) The touch sensor laminate according to (15) above, wherein the touch sensor layer is directly on the photocured organic layer.

The touch sensor layer according to the above (17), wherein the touch sensor layer comprises: an intermediate layer including an organic polymer; and an electrode pattern layer on the intermediate layer, wherein the light curing organic layer The layer is combined with the intermediate layer.

(19) The touch sensor laminate according to (18) above, wherein the intermediate layer comprises a thermosetting organic polymer.

(20) The touch sensor laminate according to the above (19), wherein the intermediate layer includes a separation layer and a protective layer which are sequentially stacked from the photocurable organic layer.

According to an exemplary embodiment as described above, the touch sensor laminate may include a first adhesive layer and a second adhesive layer, respectively, at a lower portion and an upper portion of the touch sensor layer, each adhesive layer may have a specific Peel strength within the range. The release film and the optical film may be adhered to the first adhesive and the second adhesive layer, respectively. Cracks and damage to the touch sensor layer during the separation process can be avoided or reduced due to the difference in peel strength between the first adhesive layer and the second adhesive layer.

In an exemplary embodiment, the second adhesive layer may be formed of a material whose peel strength may be lowered after light irradiation, so that the touch sensor layer may be further prevented from being damaged by the stress of the separation process.

For example, a substrate-less type thin touch sensor film can be obtained from a touch sensor laminate according to an exemplary embodiment. The touch sensor film can be applied to a flexible display device with enhanced durability and flexibility.

In order to better understand the above and other aspects of the present invention, the following detailed description of the embodiments and the accompanying drawings

According to an exemplary embodiment of the present invention, the touch sensor laminate may include a release film, a first adhesive layer, a touch sensor layer, a second adhesive layer, and an optical film. A first adhesive layer is formed on the release film. A touch sensor layer is formed on the first adhesive layer. A second adhesive layer is formed on the touch sensor layer. The optical film is adhered to the second adhesive layer. The peel strength of the second adhesive layer may be greater than the peel strength of the first adhesive layer, so that damage of the touch surface can be prevented and the touch sensor can be thinned. According to an exemplary embodiment of the present invention, a method of manufacturing a touch sensor may also be provided.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that these embodiments are described with reference to the accompanying drawings.

1 and 2 are schematic cross-sectional views of a touch sensor laminate according to example embodiments. For example, FIG. 2 shows an exemplary multilayer structure of the touch sensor layer shown in FIG. 1.

Referring to FIG. 1, a touch sensor laminate according to an exemplary embodiment of the present invention may include a release film 100, a first adhesive layer 110, a touch sensor layer 120, a second adhesive layer 130, and an optical film. 140.

The touch sensor layer 120 can include an electrode pattern. For example, the electrode pattern may include a sensing electrode for touch sensing and a pad electrode for signal transmission.

The sensing electrode may include a first sensing electrode and a second sensing electrode, which may be arranged in different directions (eg, X and Y directions) that intersect each other such that a touch position of the user may be detected.

The first adhesive layer 110 may be formed on a lower surface of the touch sensor layer 120, and the second adhesive layer 130 may be formed on an upper surface of the touch sensor layer 120. In an exemplary embodiment, the first and second adhesive layers 110 and 130 may be formed directly on the surface of the touch sensor layer 120.

The first adhesive layer 110 may be formed of, for example, a PSA adhesive. The first adhesive layer 110 may also be formed of a thermosetting or photocurable (eg, UV curable) adhesive. For example, the first adhesive layer 110 may be formed of a thermosetting or photocurable adhesive including polyesters, polyethers, polyurethanes, epoxies, organic oximes, acrylic adhesives, and the like.

The second adhesive layer 130 may include a binder material whose peel strength may be changed by light irradiation. In an exemplary embodiment, the peel strength of the second adhesive layer 130 relative to the optical film 140 and/or the touch sensor layer 120 may be reduced by UV illumination. For example, the second adhesive layer 130 may be formed of a binder composition including an acrylic copolymer and a photocurable compound.

The acrylic copolymer may comprise a polymer formed from an ester of acrylic acid or methacrylic acid; a copolymer of acrylic acid, methacrylic acid, an ester thereof or a guanamine thereof and a copolymerizable comonomer; or a mixture of a polymer and a copolymer. Wait.

The photocurable compound may include, for example, a compound which may include at least two functional groups (for example, acrylate groups) having a carbon-carbon double bond per molecule. For example, the photocurable compound may include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxy(meth)acrylate, Dipentaerythritol hexa(meth) acrylate, 1,4-butanediol di(meth) acrylate, tetraethylene glycol di(meth) acrylate, 1,6-hexanediol (meth) acrylate, Neopentyl glycol di(meth)acrylate, ester compound of (meth)acrylic acid and polyol, ester acrylate oligomer, 2-propenyl-3-butenyl cyanurate, isocyanuric acid Ester and the like. These can be used singly or in combination.

The mixing ratio of the acrylic copolymer and the photocurable compound is not particularly limited. For example, the photocurable compound may be included in an amount ranging from about 0.5 part by weight to about 200 parts by weight, preferably from about 1 part by weight to 50 parts by weight based on 100 parts by weight of the acrylic copolymer. If the amount of the photocurable compound is less than about 0.5 parts by weight, the peel strength of the second adhesive layer 130 may be excessive after light irradiation (for example, UV irradiation). If the amount of the photocurable compound exceeds about 200 parts by weight, the peel strength of the second adhesive layer 130 may become too small before UV irradiation due to an increase in the low molecular weight material.

The binder composition may further include a photopolymerization initiator, a UV sensitizer, a crosslinking agent, and the like.

The photopolymerization initiator may include, for example, acetophenone, benzophenone, Michler's ketone, benzoin, benzyl methyl ketal, benzhydryl benzoate, α-mercapto oxime ester, thioxanthone Wait. The UV sensitizer may include, for example, n-butylamine, triethylamine, tri-n-butylphosphine, and the like. The crosslinking agent may include, for example, an isocyanate crosslinking agent.

The release film 100 may be formed on the lower surface of the first adhesive layer 110. In some embodiments, the release film 100 can be directly adhered to the lower surface of the first adhesive layer 110. The release film 100 may include, for example, a melamine-based film, an acrylic film, a polyethylene-based film, a paper film, or the like.

The optical film 140 may be formed on the upper surface of the second adhesive layer 130. In some embodiments, the optical film 140 may be formed directly on the upper surface of the second adhesive layer 130. In some embodiments, the upper surface of the touch sensor layer 120 to which the second adhesive layer 130 is adhered can be used as a touch surface into which a user's touch can be input.

The optical film 140 can be used as a protective film of the touch sensor layer 120 and the touch sensor laminate. For example, the optical film 140 may include a cellulose ester (eg, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, nitrocellulose, etc.), polyimine, polycarbonate, poly Ester, polyethylene terephthalate, polystyrene, polyolefin, polyfluorene, polyether oxime, polyarylate, polyether oximine, polymethyl methacrylate, polyether ketone, polyvinyl alcohol A transparent resin film formed of polyvinyl chloride or the like. These can be used singly or in combination.

In some embodiments, optical film 140 can include an optically functional film, such as a polarizing film, a retardation film, and the like.

According to an exemplary embodiment, the peel strength of the first adhesive layer 110 with respect to the release film 100 (eg, the peel strength before UV irradiation) may be less than the peel strength of the second adhesive layer 130 with respect to the optical film 140. Therefore, when the release film 100 is removed or separated, the optical film 140 can remain on the touch sensor layer 120, so that damage such as cracks of the touch sensor layer 120 can be prevented.

In some embodiments, the peel strength of the first adhesive layer 110 relative to the release film 100 can be about 0.2 N/25 mm or less, preferably about 0.1 N/25 mm or less. The peel strength of the second adhesive layer 130 relative to the optical film 140 or the touch sensor layer 120 may range from about 0.2 N/25 mm to about 20 N/25 mm.

If the peel strength of the second adhesive layer 130 may be less than about 0.2 N/25 mm, the optical film 140 may also be separated or damaged when the release film 100 is separated. If the peel strength of the second adhesive layer 130 may exceed about 20 N/25 mm, the peel strength of the second adhesive layer 130 may not be sufficiently lowered after light irradiation (for example, UV irradiation) to cause subsequent removal of the optical film 140. The damage of the touch sensor layer 120 is touched.

As described above, the peel strength of the second adhesive layer 130 can be lowered after light irradiation. In some embodiments, the peel strength of the second adhesive layer 130 may become about 0.2 N/25 mm or less, preferably about 0.1 N/25 mm or less.

The viscoelasticity of the first adhesive layer 100 can be adjusted in consideration of improving the flexibility performance and preventing cracks when separating the release film 100 of the touch sensor laminate. In some embodiments, the first adhesive layer 100 may have a viscoelasticity (storage modulus) ranging from about 10 ⁴ Pa to about 10 ¹⁰ Pa.

Referring to FIG. 2, the touch sensor layer 120 interposed between the first adhesive layer 110 and the second adhesive layer 130 may have a multilayer structure including a plurality of layers. In an exemplary embodiment, the touch sensor layer 120 may include an intermediate layer, an electrode pattern 126, and a second protective layer 128 (eg, an upper protective layer) formed in order from the upper surface of the first adhesive layer 110. The intermediate layer may include a separation layer 122 and a first protective layer 124 (eg, a lower protective layer). At least one of the separation layer 122 and the first protective layer 124 may include an organic polymer.

In some embodiments, the intermediate layer can include a separation layer 122 or a first protective layer 124.

The separation layer 122 can serve as a functional layer to facilitate separation of the touch sensor layer 120 from the carrier substrate 50 (see Figure 3A). The separation layer 122 may be formed as an organic polymer layer, and may include, for example, polyimine, polyvinyl alcohol, polyglycolic acid, polyamine, polyethylene, polystyrene, polynorbornene, phenyl mala Imine copolymer, polyazobenzene, polyphenylene phthalamide, polyester, polymethyl methacrylate, polyarylate, cinnamate polymer, coumarin polymer, benzene And [c] pyrrolidone, chalcone polymer, aromatic acetylene polymer, and the like. These can be used alone or in combination.

In some embodiments, the separation layer 122 may include a thermosetting polymer and thus may be formed as a thermally cured organic layer.

The separation layer 122 may be formed of a material that can be easily separated from the carrier substrate 50 to prevent cracks in the touch sensor layer 120. Accordingly, the separation layer 122 may be formed such that the peel strength of the separation layer 122 relative to the carrier substrate 50 may be no greater than about 1 N/25 mm, preferably no greater than about 0.1 N/25 mm.

The first protective layer 124 may be formed to provide protection of the electrode pattern 126 and/or to improve optical performance by a refractive index that matches the electrode pattern 126. The first protective layer 124 may include an inorganic material such as hafnium oxide, tantalum nitride, hafnium oxynitride, or a polymer-based organic insulating material.

As described above, the electrode pattern 126 may include a sensing electrode for touch sensing and a pad electrode for signal transmission. The sensing electrode may include a first sensing electrode and a second sensing electrode, which are arranged in two directions crossing each other.

In some embodiments, the bridge electrode can be formed such that one of the first and second sensing electrodes can be electrically connected and can be insulated from the other of the first and second sensing electrodes. For example, an insulating layer at least partially covering the second sensing electrode may be formed, and the bridge electrode may be electrically connected to the adjacent first sensing electrode through a contact hole formed in the insulating layer.

The electrode pattern 126 may include a unit electrode having a polygonal shape such as a rhombic shape. In an embodiment, the unit electrodes may be arranged in a mesh shape. In an embodiment, the unit electrodes may be arranged irregularly.

The second protective layer 128 may be formed on the first protective layer 124 to cover the electrode pattern 126. The second protective layer 128 may protect the upper surface of the electrode pattern 126 (eg, a touch sensing surface) and may function as a leveling layer or an overcoat layer. The second protective layer 128 may include an organic or inorganic insulating material.

As described with reference to FIGS. 1 and 2, the first adhesive layer 110 and the second adhesive layer 130 may be formed on the lower surface and the upper surface of the touch sensor layer 120, respectively, so that the touch sensor layer 120 may be protected. It is protected from damage such as cracks during subsequent processes such as separation processes.

The first adhesive layer 110 may have a predetermined viscoelasticity such that the flexible performance of the touch sensor laminate can be improved. The first adhesive layer 110 may be formed to have a smaller initial peel strength than the second adhesive layer 130, so that separation of the release film 100 may be promoted without damaging the touch sensor laminate.

The second adhesive layer 130 may be formed to have a greater initial peel strength than the first adhesive layer 110 such that the touch surface of the touch sensor layer 120 may be protected. The second adhesive layer 130 may be formed of a material whose peel strength can be lowered by light irradiation such as UV irradiation. Therefore, the optical film 140 can be easily removed or separated.

According to the structure as described above, a substantially substrateless type touch sensor film having high reliability can be obtained from the touch sensor laminate. The touch sensor film can be combined with a display panel to implement a flexible display device.

3A-3D are cross-sectional schematic views of a method of fabricating a touch sensor stack, in accordance with some example embodiments. Detailed descriptions of substantially the same or similar elements and/or materials as described with reference to FIGS. 1 and 2 are omitted herein.

Referring to FIG. 3A, the touch sensor layer 120, the second adhesive layer 130, and the optical film 140 may be sequentially formed on the carrier substrate 50.

For example, a glass substrate can be used as the carrier substrate. The touch sensor layer 120 may include an electrode pattern formed of, for example, a conductive metal oxide such as ITO, a metal, a nanowire, a carbon-based conductive material, and/or a conductive polymer.

The electrode pattern can be, for example, by physical vapor deposition, sputtering process, chemical vapor deposition, plasma deposition, plasma polymerization, thermal deposition, thermal oxidation, anodization, cluster ion beam deposition, screen printing, gravure printing, flexography Printing, offset printing, inkjet coating, dispenser printing, and the like are formed.

As shown in FIG. 2, the touch sensor layer 120 may be formed by sequentially stacking the separation layer 122, the first protective layer 124, the electrode pattern 126, and the second protective layer 128. The separation layer 122, the first protective layer 124, and the second protective layer 128 may be, for example, by slit coating, blade coating, spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar Coating, deep coating, spray coating, screen printing, gravure printing, flexographic printing, offset printing, inkjet coating, dispenser printing, nozzle coating, capillary coating, and the like.

The second adhesive layer 130 may be formed on an upper surface (eg, a touch surface) of the touch sensor layer 120, and the optical film 140 may be formed on the second adhesive layer 130. The second adhesive layer 130 may be formed using a material whose peel strength relative to the optical film 140 may range from about 0.2 N/25 mm to about 20 N/25 mm.

Referring to FIG. 3B, the carrier substrate 50 may be separated or separated from the touch sensor layer 120, and then the first adhesive layer 110 may be formed on the lower surface of the touch sensor layer 120 from which the carrier substrate 50 may be removed. . Subsequently, the release film 100 may be adhered to the lower surface of the first adhesive layer 110.

In an exemplary embodiment, the peel strength of the first adhesive layer 110 relative to the release film 100 may be about 0.2 N/25 mm or less, preferably about 0.1 N/25 mm or less. In some embodiments, the first adhesive layer 110 can be formed to have a viscoelasticity (storage modulus) ranging from about 10 ⁴ Pa to about 10 ¹⁰ Pa.

The first and second adhesive layers 110 and 130 may be formed by a coating method or a printing method generally known in the art.

Subsequently, an additional process of applying the touch sensor laminate obtained from the process of FIG. 3B to the display panel may be performed.

Referring to FIG. 3C, the release film 100 may be separated or removed from the first adhesive layer 110, and then the base film 60 may be adhered to the lower surface of the first adhesive layer 110 from which the release film 100 is removed. The substrate film 60 may include a material that is substantially impermeable to ultraviolet rays, and may include a resin film such as a polyimide film or a metal film. In some embodiments, substrate film 60 can comprise a UV permeable material.

In some embodiments, substrate film 60 can include various optical, electrical, and/or electromagnetic functional films such as polarizing films, barrier films, barrier films, antenna films, and the like. In some embodiments, the substrate film 60 can include a display panel or display substrate (eg, a backside substrate). In some embodiments, substrate film 60 can include input devices and/or sensors such as digital converters, force touch sensors, IoT sensors, fingerprint sensors, and the like.

Referring to FIG. 3D, light (for example, UV light) may be irradiated to the optical film 140, and then the optical film 140 may be removed. According to an exemplary embodiment, the peel strength of the second adhesive layer 130 may be reduced to about 0.2 N/25 mm or less, preferably about 0.1 N/25 mm or less. Therefore, the optical film 140 can be easily separated, and stress generated from the separation process can be prevented, so that damage of the touch sensor layer 120 can be prevented.

In some embodiments, the second adhesive layer 130 can also be removed from the touch sensor layer 120 along with the optical film 140.

After the method as described above, the first adhesive layer 110 and the touch sensor layer 120 may remain on the substrate film 60, and a thin layered touch feeling with enhanced flexibility through the first adhesive layer 110 may be obtained. Tester membrane.

4A through 4D are cross-sectional schematic views of a method of fabricating a touch sensor stack, in accordance with some example embodiments. Detailed descriptions of substantially the same or similar to the methods shown with reference to FIGS. 3A to 3D are omitted here.

Referring to FIG. 4A, a method substantially the same as or similar to those shown with reference to FIGS. 3A and 3B can be performed to form a touch sensor laminate.

Referring to FIG. 4B, light irradiation such as UV irradiation can be performed from the lower portion of the release film 100. The first adhesive layer 110 may be photocured by light irradiation, so that the hardness of the first adhesive layer 110 may be increased. Further, the peel strength of the first adhesive layer 110 with respect to the release film 100 can be lowered.

Referring to FIG. 4C, the release film 100 can be separated or removed from the first adhesive layer 110. The release film can be easily removed by the above-described light irradiation with a relatively low peel strength.

Referring to FIG. 4D, the optical film 140 and the second adhesive layer 130 may be removed from the touch sensor layer 120. According to example embodiments, light irradiation may be performed as described with reference to FIG. 3D to reduce the peel strength of the second adhesive layer 130, and then the optical film 140 and the second adhesive layer 130 may be separated or removed.

Therefore, a touch sensor film consisting essentially of the first adhesive layer 110 and the touch sensor layer can be obtained, and the first adhesive layer 110 cured by the above light irradiation can be basically used as a substrate film. Therefore, an ultra-thin touch sensor film without an additional substrate film can be realized.

FIG. 5 illustrates a cross-sectional schematic view of a touch sensor stack in accordance with some example embodiments.

Referring to FIG. 5, the touch sensor stack may include a touch sensor layer 120 disposed on the photocured organic layer 210. As shown in FIG. 5, the touch sensor stack may consist essentially of the photocurable organic layer 210 and the touch sensor layer 120. In some embodiments, the touch sensor layer 120 can be disposed directly on the photocured organic layer 210.

As described above, the touch sensor layer 120 may include an electrode pattern, which may include a sensing electrode, a pad electrode, and the like. In some embodiments, the touch sensor layer can include the multilayer structure described with reference to FIG.

The photocured organic layer 210 may be substantially used as a substrate or a substrate film of a touch sensor laminate. Therefore, a touch sensor laminate having no additional substrate film can be obtained as a film.

In some embodiments, the photocurable organic layer 210 can include an adhesive layer (eg, first adhesive layer 110) as described with reference to Figures 4B through 4D.

In some embodiments, the photocurable organic layer 210 may be formed of a photocurable resist composition or a resist layer. In an exemplary embodiment, the photocurable organic layer 210 may be formed of a dry film or a dry film resist (DFR).

For example, the dry film resist may include a binder resin, a photocurable compound, a photopolymerization initiator, and an additive, and may have a negative tone property.

The binder resin may include a polymer that can be developed with an alkaline solution. For example, the binder resin may include an acrylic polymer, a polyester, a polyurethane, or the like. Preferably, the acrylic polymer may comprise a methacrylic copolymer. In an embodiment, an ethylenically unsaturated carboxylic acid and other monomers may be further used.

The methacrylic monomer used for the synthesis of the methacrylic copolymer may include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, methyl 2-ethylhexyl acrylate, cyclohexyl methacrylate, benzyl methacrylate, dimethylaminoethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate Ester and the like.

The ethylenically unsaturated carboxylic acid may include a monocarboxylic acid such as acrylic acid, methacrylic acid, crotonic acid or the like. In an embodiment, a dicarboxylic acid such as maleic acid, fumaric acid, itaconic acid or the like, or an ester or anhydride thereof may be used.

Other monomers may include acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, styrene, methyl styrene, vinyl acetate, alkyl vinyl ether, and the like.

The photocurable compound may include, for example, a monomer having at least two vinyl groups at its end. For example, an acrylate monomer having at least two functional groups.

The photopolymerization initiator may be a compound that initiates a chain reaction of a photocurable compound by light irradiation such as UV irradiation, and may provide photocurability properties to the dry film resist. The photopolymerization initiator may include, for example, an anthracene derivative such as 2-methylanthracene and 2-ethylanthracene; a benzoin derivative such as benzoin methyl ether, benzophenone, phenanthrenequinone and 4 , 4'-bis-(dimethylamino)benzophenone and the like.

The additive may include, for example, a plasticizer, a softener, a leveling agent, and the like. For example, vinyl chloride resin, phthalate, adipate, etc. may be included to improve uniform surface properties.

The photocured organic layer 210 may have improved strength, elasticity, and surface properties. Therefore, a touch sensor laminate having a reduced thickness with improved flexibility and mechanical properties can be realized.

For example, the photocurable organic layer 210 may be formed of a dry film or a dry film resist, and the photocurable organic layer 210 may have a compressive modulus of about 5 GPa or more. For example, the compressive modulus of the photocurable organic layer 210 may range from about 5 GPa to about 8 GPa.

If the compressive modulus of the photocurable organic layer 210 is less than about 5 GPa, sufficient durability and external impact resistance may not be obtained. If the compressive modulus of the photocurable organic layer 210 exceeds about 8 GPa, the flexibility performance of the touch sensor laminate may be lowered.

The tensile strength of the photocured organic layer 210 may be about 40 N/mm ² or more. For example, the tensile strength of the photocurable organic layer 210 may range from about 40 N/mm ² to about 50 N/mm ² .

In some embodiments, the photocured organic layer 210 may have a thickness of about 10 μm or less. The retardation value (R ₀ ) of the photocured organic layer 210 may be about 10 nm or less. For example, the photocured organic layer 210 may be formed using a dry film resist as a thin layer having a thickness of about 10 μm or less, and the retardation value may be adjusted to be about 10 nm or less. Therefore, the optical and mechanical properties of the touch sensor laminate can be improved with a thin film structure.

In some embodiments, the touch sensor layer 120 can include an intermediate layer formed between the electrode pattern and the photo-cured organic layer 210. The intermediate layer may include the separation layer 122 and/or the protective layer 124 shown in FIG.

The intermediate layer may comprise an organic polymer. In an embodiment, the intermediate layer may include a thermosetting polymer, and the photocurable organic layer 210 may include the above-described photocurable resist or photocurable adhesive.

The photocurable organic layer 210 may have a compressive modulus greater than that of the intermediate layer. For example, the compressive modulus of the intermediate layer can range from about 2 GPa to about 4 GPa.

The intermediate layer may be formed of an organic polymer selected in consideration of easy deposition of an electrode pattern and prevention of electrode pattern diffusion corrosion by an organic material. The photocured organic layer 210 may be formed of a material that considers the mechanical properties desired as a substrate.

As described above, the intermediate layer may include a thermosetting polymer. Therefore, denaturation or modification of the intermediate layer can be prevented in the process of the light irradiation method for forming the photocurable organic layer 210.

6A-6E illustrate cross-sectional schematic views of a method of fabricating a touch sensor stack, in accordance with some example embodiments. For example, FIGS. 6A to 6E illustrate a method of the touch sensor stack shown in FIG. 5.

Referring to FIGS. 6A and 6B, the preliminary touch sensor laminate 150 and the photocurable organic layer laminate 200 may be separately prepared.

The preliminary touch sensor stack 150 can be formed by sequentially forming the touch sensor layer 120, the second adhesive layer 130, and the optical film 140 on the carrier substrate 50a. The preliminary touch sensor stack 150 may have substantially the same or similar structure or configuration as those shown in FIG. 3A.

The photocurable organic laminate 200 can be used as a laminate sheet or a laminate film. For example, the photocurable organic laminate 200 may include a carrier film 50b, a photosensitive organic layer 205, and a protective film 220.

For example, the carrier film 50b may include a resin film such as a polyethylene terephthalate (PET) film. The protective film 220 may include a resin film such as a polyethylene (PE) film or a polypropylene (PP) film. The photosensitive organic layer 205 may include the above dry film resist.

Referring to FIG. 6C, the preliminary touch sensor laminate 150 and the photocurable organic laminate 200 may be bonded to each other.

For example, the carrier substrate 50a may be separated from the preliminary touch sensor laminate 150, and the protective film 220 may be separated from the photocurable organic laminate 200.

Subsequently, the photosensitive organic layer 205 may be adhered to the lower surface of the touch sensor layer 120 from which the carrier substrate 50a may be separated.

Referring to FIG. 6D, the carrier film 50b may be removed or separated from the photosensitive organic layer 205, and then light irradiation (for example, UV irradiation) may be performed from the lower portion of the photosensitive organic layer 205.

When light irradiation is performed, the photocurable compound and the binder resin contained in the dry film resist may be crosslinked or networked by a photopolymerization initiator contained in the photosensitive organic layer 205 to form a photocured organic layer. 210. The compression modulus of the photocured organic layer 210 can be adjusted within the above range by light irradiation.

Referring to FIG. 6E, the optical film 140 and the second adhesive layer 130 may be removed from the touch sensor layer 120. Thus, a touch sensor laminate substantially composed of the touch sensor layer 120 and the photocurable organic layer 210 can be obtained.

In an exemplary embodiment, as described with reference to FIG. 3D, UV irradiation may be performed toward the upper portion of the optical film 140 so that the peel strength of the second adhesive layer 130 may be lowered, and then the optical film 140 may be removed.

In an exemplary embodiment, the light irradiation for forming the photo-cured organic layer 210 may be performed with an irradiation amount larger than the separation of the second adhesive layer 130. Therefore, the elasticity and/or mechanical strength of the photocurable organic layer 210 can be improved, so that it can be basically used as a substrate.

According to an exemplary embodiment, an image display device including the touch sensor laminate or the touch sensor film as described above may also be provided. The image display device may include a flexible display device such as a flexible OLED device, a flexible LCD device, or the like.

In an exemplary embodiment, a thin film transistor (TFT) array may be disposed on a flexible substrate, and a touch sensor laminate or a touch sensor film may be disposed on the TFT array. The window substrate can be disposed on the touch sensor stack or the touch sensor film.

As described above, when the optical film 140 and/or the release film 110 can be removed, damage of the touch sensor layer 120 can be removed, and a thin touch sensor film can be obtained from the touch sensor laminate. The touch sensor film can be combined with a flexible display panel, and a thin display device with high reliability can be realized.

In the following, preferred embodiments are presented to more specifically describe the invention. However, the following examples are only intended to illustrate the invention, and those skilled in the art will understand that these embodiments do not limit the appended claims, but various changes and modifications can be made within the scope and spirit of the invention. . Such changes and modifications are of course included in the appended claims.

Experimental example 1

Examples and comparative examples

A soda lime glass having a thickness of 700 μm was used as a carrier substrate. A separation layer composition including a melamine-based resin, a cinnamate-based resin, and a propylene glycol monomethyl ether acetate is coated to have a thickness of 100 to 600 nm, prebaked at 100 to 130 ° C for 2 minutes, and at 150 to 180 Post-baking at ° C for 5 minutes to form a separation layer.

The protective layer composition (by mixing a polyfunctional acrylic monomer and a ring in a solvent of 30 parts by weight of diethylene glycol methyl ethyl ether (MEDG), 40 parts by weight of PGMEA, and 30 parts by weight of 3-methoxybutanol The oxy-based resin was prepared by having a solid content of 20 parts by weight), coated on the separation layer to have a thickness of 2 μm, and dried and cured at 230 ° C for 30 minutes.

An ITO layer was deposited on the protective layer at 25 ° C to have a thickness of 45 nm, and annealed at 230 ° C for 30 minutes to form an electrode pattern layer. A second protective layer having a thickness of 1.5 μm was formed on the electrode pattern layer using ruthenium oxide.

A second adhesive layer is formed on the second protective layer, and a polyethylene terephthalate film is formed on the second adhesive layer (separation film, MRF, manufactured by Mitsubishi Chemical Polyester Film, thickness: 100 μm, stretched Modulus: 90 MPa) as an optical film.

The carrier substrate is separated from the separation layer, and a first adhesive layer is formed on the lower surface of the separation layer. A polyethylene release film having a thickness of 18 μm was adhered to the first adhesive layer to obtain touch sensor laminates of Examples (Examples 1-5) and Comparative Examples. The first and second adhesive layers are formed using a photocurable PSA composition comprising an acrylic copolymer.

The composition, thickness, curing temperature, and the like of the adhesive composition are adjusted to change the peel strength of the first and second adhesive layers. Specifically, in an embodiment, the initial peel strength of the first adhesive layer is less than the initial peel strength of the second adhesive layer. In Comparative Examples 1 and 2, the initial peel strength of the first adhesive layer was equal to or greater than the initial peel strength of the second adhesive layer.

The peel strength of the first and second adhesive layers was measured by separating the release film and the optical film. Light irradiation was performed on the optical film using ultraviolet light of 250 mJ/cm ² , and then the optical film was peeled off to measure the peel strength of the second adhesive layer after light irradiation. Specifically, the release film or the optical film was pressed using a transfer roller, and then, when the peel strength was measured, separation was performed using UTM automatic recording AG-X (1 KN) (peeling speed: 300 mm/min, 90°). The measurement results are shown in Table 1 below.

[Table 1]

In Example 6 of Table 1, a dry film resist was used instead of the first adhesive layer. Specifically, an intermediate layer including a separation layer and a protective layer is formed on a carrier substrate, and then an electrode pattern layer, a second protective layer, and a second adhesive are formed on the intermediate layer in the same manner as those of Embodiments 1 to 5. Layer and optical film.

The carrier substrate is separated from the intermediate layer and a dry film resist is bonded to the lower surface of the intermediate layer. Specifically, a DFR laminate (HITACHI Chemical, RY-3315) including a carrier film (PET), a dry film resist, and a protective film (PE) was prepared. The protective film was removed from the DFR laminate and then adhered to the intermediate layer.

Subsequently, the carrier film was removed, and 1000 mJ/cm ² of UV light was irradiated on the dry film resist to form a photocured organic layer. After the irradiation, the optical film and the second adhesive layer are separated to obtain a touch sensor laminate.

The compressive modulus values of the intermediate layer and the photocured organic layer were 3.8 GPa and 5.2 GPa, respectively. The compression modulus was measured based on the ISO/FDIS 14577-1 standard.

1) Evaluation of damage/delamination of optical film when removing release film

The release film was separated from each of the touch sensor laminates of the examples and the comparative examples. Damage/delamination of the optical film from the second adhesive layer was evaluated by the following criteria.

In Example 6, the damage/delamination of the optical film from the DFR laminate when the carrier film was separated was evaluated.

○: The optical film was completely free from damage and delamination.

△: The optical film was partially delaminated (less than 1/2).

X: 1/2 or more damage and delamination of the optical film

2) Evaluation of residue from the second adhesive layer after removal of the optical film

After the release film is removed, the optical film is irradiated with light, and then the optical film is separated. The residue of the second adhesive layer on the second protective layer was evaluated by the following criteria.

○: no residue (the second adhesive layer was completely removed)

X: The residue of the second adhesive layer was observed.

3) Evaluation of crack/damage of the touch sensor layer

After the release film and the optical film were removed as described above, the crack of the touch sensor layer including the electrode pattern was observed and evaluated by the following criteria.

○: no crack

△: Five or less cracks were observed.

X: More than 6 cracks were observed.

The results are shown in Table 2 below.

[Table 2]

Referring to Table 2, in a comparative example in which the initial peel strength of the first adhesive layer is greater than or equal to the initial peel strength of the second adhesive layer, a portion of the touch sensor layer is separated from the second adhesive layer to transfer to the first A layer of adhesive and a release film. Therefore, the touch sensor layer is damaged or broken and is not sufficiently protected.

In Example 3 in which the initial peel strength (before light irradiation) was larger than the initial peel strengths of Examples 1 and 2, the peel strength was not sufficiently lowered after light irradiation. Therefore, after the removal of the optical film, the residue of the second adhesive layer is partially generated, and the crack of the touch sensor layer is partially observed.

In Example 4 in which the initial peel strength was greater than the initial peel strength of Examples 1 to 3, when the release film was removed, the optical film was also partially damaged to cause partial cracks in the touch sensor layer.

In Example 5 in which the peel strength of the second adhesive layer was not sufficiently lowered after light irradiation, stress was generated upon removal of the optical film to generate a partial crack and a residue of the second adhesive layer.

In Example 6 in which a photocured organic layer was formed using a DFR laminate, enhanced crack resistance was achieved as in Example 1 without causing film delamination and residue.

In conclusion, the present invention has been disclosed in the above embodiments, but it is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

50, 50a‧‧‧ Carrier substrate

50b‧‧‧ carrier film

60‧‧‧Base film

100‧‧‧ release film

110‧‧‧First adhesive layer

120‧‧‧Touch sensor layer

122‧‧‧Separation layer

124‧‧‧First protective layer

126‧‧‧electrode pattern

128‧‧‧Second protective layer

130‧‧‧Second adhesive layer

140‧‧‧Optical film

150‧‧‧Preliminary touch sensor stack

200‧‧‧Photocurable organic laminate

205‧‧‧Photosensitive organic layer

210‧‧‧Photocured organic layer

220‧‧‧Protective film

FIG. 1 is a schematic cross-sectional view of a touch sensor laminate according to an exemplary embodiment. 2 is a cross-sectional schematic view of a touch sensor stack in accordance with some example embodiments. 3A-3D are cross-sectional schematic views of a method of fabricating a touch sensor stack, in accordance with some example embodiments. 4A through 4D are cross-sectional schematic views of a method of fabricating a touch sensor stack, in accordance with some example embodiments. FIG. 5 illustrates a cross-sectional schematic view of a touch sensor stack in accordance with some example embodiments. 6A-6E illustrate cross-sectional schematic views of a method of fabricating a touch sensor stack, in accordance with some example embodiments.

Claims (20)

A touch sensor stack includes: a touch sensor layer; a second adhesive layer formed on an upper surface of the touch sensor layer; a first adhesive layer formed on the touch sensing The peeling strength of the first adhesive layer is less than the peel strength of the second adhesive layer on the lower surface of the layer; a release film adheres to the lower surface of the first adhesive layer; and an optical film adheres On the upper surface of the second adhesive layer. The touch sensor laminate according to claim 1, wherein the first adhesive layer has a peel strength of 0.2 N/25 mm or less, and the second adhesive layer has a peel strength of 0.2 N/25 mm. Up to 20N/25mm. The touch sensor laminate of claim 1, wherein the second adhesive layer comprises a material whose peel strength is lowered by a light irradiation. The touch sensor laminate of claim 3, wherein the second adhesive layer has a peel strength before the light irradiation in a range of 0.2 N/25 mm to 20 N/25 mm, the second adhesive. The peel strength of the agent layer after the light irradiation was 0.2 N/25 mm or less. The touch sensor laminate of claim 1, wherein the touch sensor layer comprises a multilayer structure including an electrode pattern. The touch sensor laminate of claim 5, wherein the touch sensor layer comprises an intermediate layer, an electrode pattern layer and an upper layer comprising an organic polymer stacked in this order from the first adhesive layer. The protective layer. The touch sensor laminate of claim 6, wherein the intermediate layer comprises a separation layer and a lower protective layer stacked in this order from the first adhesive layer. The touch sensor laminate of claim 1, wherein the optical film comprises a protective film formed of a polymer. The touch sensor laminate of claim 1, wherein the second adhesive layer and the optical film are formed on a touch surface of the touch sensor layer. A method of manufacturing a touch sensor laminate, comprising: sequentially forming a touch sensor layer, a second adhesive layer, and an optical film on a carrier substrate; and using the carrier substrate from the touch sensor Layer separation; forming a first adhesive layer on a lower surface of the touch sensor layer from which the carrier substrate is removed, the peel strength of the first adhesive layer being less than the peel strength of the second adhesive layer; A release film is adhered to the lower surface of the first adhesive layer. The method of claim 10, further comprising: separating the release film from the first adhesive layer; adhering a substrate film to the first adhesive layer from which the release film is removed Surface; and removing the optical film. The method of claim 11, wherein the removing the optical film comprises: reducing the peel strength of the second adhesive layer by irradiating the optical film with light. The method of claim 12, wherein the substrate film comprises a material that does not transmit ultraviolet light. The method of claim 10, further comprising: curing the first adhesive layer by irradiating light to the release film; removing the release film; and using the cured first adhesive layer as a base Material to remove the optical film. A touch sensor laminate comprising: a photocurable organic layer; and a touch sensor layer on the photocurable organic layer. The touch sensor laminate of claim 15, wherein the photocurable organic layer comprises a binder layer, and a dry film or dry film resist. The touch sensor laminate of claim 15, wherein the touch sensor layer is directly on the photocured organic layer. The touch sensor layer of claim 17, wherein the touch sensor layer comprises: an intermediate layer comprising an organic polymer; and an electrode pattern layer on the intermediate layer, wherein The photocured organic layer is combined with the intermediate layer. The touch sensor laminate of claim 18, wherein the intermediate layer comprises a thermosetting organic polymer. The touch sensor laminate of claim 19, wherein the intermediate layer comprises a separation layer and a protective layer stacked in this order from the photocurable organic layer.