KR20160034091A - Flexible Device and Method for Manufacturing the Same - Google Patents

Abstract

The present invention relates to a method for manufacturing a flexible device and a flexible device manufactured by the method. The method includes a step of attaching an ultraviolet non-transparent base film including a conductive layer onto a carrier substrate with adhesive; a step of forming a conductive pattern layer by patterning the conducive layer; a step of providing a flexible device by forming an insulating layer on the conducive pattern layer; and a step of hardening the adhesive by emitting an ultraviolet ray to the adhesive from the carrier substrate and peeling the flexible device from the carrier substrate. According to the manufacturing method, a base film can be stably attached onto the carrier substrate while the flexible display device is formed. After a device process, the flexible device can be easily peeled from the carrier substrate.

Description

Technical Field [0001] The present invention relates to a flexible device and a manufacturing method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a flexible element and a method of manufacturing the same, and more particularly, to a flexible element manufactured by bonding a plastic substrate on a carrier substrate and forming a display element thereon.

As the information society develops, the demand for display devices is gradually increasing in various forms. In response to this, various flat panel display devices such as a liquid crystal display, a plasma display panel, and an organic light emitting diode have been studied.

As the use of such a flat panel display device is rapidly expanded, the development of a flexible display device which can be folded like a paper has been concentrated.

The flexible display device can be realized by replacing the conventional glass substrate with a flexible plastic substrate. However, since it is difficult to directly perform a device process for forming a display device on a plastic substrate, a display device is formed using the carrier substrate. That is, in order to form the flexible display device, a plastic substrate is first formed on the carrier substrate. Thereafter, a device process is performed on the plastic substrate, and a desorption process for separating the plastic substrate from the carrier substrate is performed to manufacture a flexible display device.

At this time, the carrier substrate and the plastic substrate may be adhered to each other during the device process by an adhesive. As a pressure-sensitive adhesive used therefor, a pressure-sensitive adhesive capable of reversibly controlling the adhesive force by heat has been proposed. When the heat-sensitive adhesive contains a side chain crystalline polymer and heat treatment is performed to a temperature not lower than the melting point of the side chain crystalline polymer, the side chain crystalline polymer exhibits fluidity to exhibit an adhesive force, The adhesive force is lowered and the flexible substrate can be peeled from the support substrate (see Korean Patent Publication No. 2011-0127124). However, since the side chain crystalline polymer used in the pressure sensitive adhesive is expensive, there is a problem in applying it to commercial mass production.

Korean Patent Publication No. 2011-0127124

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a method for manufacturing a flexible device, which uses an ultraviolet opaque base film together with a relatively inexpensive adhesive, And the flexible device can be easily peeled off from the carrier substrate after the device process.

Another object of the present invention is to provide a flexible element manufactured by the above method.

It is still another object of the present invention to provide a flexible display device provided with the flexible element.

On the other hand,

(I) bonding an ultraviolet light-impermeable base film including a conductive layer on a carrier substrate with an adhesive;

(Ii) patterning the conductive layer to form a conductive pattern layer;

(Iii) forming an insulating layer on the conductive pattern layer to provide a flexible element; And

(Iv) a step of peeling the flexible element from the carrier substrate by irradiating ultraviolet rays to the pressure-sensitive adhesive in the direction of the carrier substrate to harden the pressure-sensitive adhesive.

In one embodiment of the present invention, the ultraviolet-impermeable base film is characterized by having a ultraviolet transmittance of 400 nm or less of 5% or less.

In one embodiment of the present invention, the pressure-sensitive adhesive is characterized in that a photopolymerizable compound and a photoinitiator are added to the pressure-sensitive adhesive.

On the other hand, the present invention provides a flexible element comprising an ultraviolet-opaque base film, a conductive pattern layer formed on the base film, and an insulating film formed on the conductive pattern layer.

In one embodiment of the present invention, the ultraviolet-impermeable base film is characterized by having a ultraviolet transmittance of 400 nm or less of 5% or less.

On the other hand, the present invention provides a flexible display device provided with the flexible element.

In an embodiment of the present invention, the flexible display device may be a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED) (Electrophoretic Display: EPD).

According to the method for producing a flexible element of the present invention, a photopolymerizable compound and a photoinitiator are added to a comparatively inexpensive pressure-sensitive adhesive to impart a tackiness in the step of bonding a base film onto a carrier substrate, So that the adhesive force is reduced and the flexible element can be easily peeled off.

Further, by using an ultraviolet-impermeable base film, it is possible to prevent the pressure-sensitive adhesive from being deteriorated due to curing of the pressure-sensitive adhesive by ultraviolet rays irradiated during the device process.

1A to 1D are process cross-sectional views schematically showing a manufacturing method of a flexible element according to an embodiment of the present invention.
2 is a structural cross-sectional view of a flexible element according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1A to 1D are process cross-sectional views schematically showing a manufacturing method of a flexible element according to an embodiment of the present invention. 1A to 1D, a method of manufacturing a flexible element according to an embodiment of the present invention includes:

(I) bonding an ultraviolet-impermeable base film (110) comprising a conductive layer (120) on a carrier substrate (200) with an adhesive (150);

(Ii) patterning the conductive layer 120 to form a conductive pattern layer 125;

(Iii) providing an insulating layer (130) on the conductive pattern layer (125) to provide a flexible element (100); And

(Iv) a step of peeling the flexible element 100 from the carrier substrate 200 by irradiating the adhesive 150 with ultraviolet rays in the direction of the carrier substrate to harden the adhesive.

First, as shown in FIG. 1A, an ultraviolet-impermeable base film 110 including a conductive layer 120 is bonded on a carrier substrate 200 with an adhesive 150.

The carrier substrate 200 may serve to support the substrate film 120 during a conductive pattern layer and a flexible element forming process, which will be described later. Specifically, a glass substrate, a metal substrate, or the like may be used. Of these, a glass substrate is preferable.

The ultraviolet-impermeable base film 110 including the conductive layer 120 may be manufactured beforehand on the carrier substrate 200 or may be formed on the carrier substrate 200 using an ultraviolet-impermeable base film 110 The conductive layer 120 may be formed after bonding.

The conductive layer 120 may be formed of, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO) (FTO), indium tin oxide-silver-indium tin oxide (ITO-Ag-ITO), indium zinc oxide-silver-indium zinc oxide (IZO-Ag-IZO), indium zinc tin oxide- IZTO-Ag-IZTO) and aluminum zinc oxide-silver-aluminum zinc oxide (AZO-Ag-AZO); Metals such as gold (Au), silver (Ag), copper (Cu) and molybdenum (Mo); Metal nanowires such as Ag, Au, Cu, and Pt nanowires; Carbon-based materials such as carbon nanotubes (CNT) and graphene; PEDOT, PANI, and the like.

In one embodiment of the present invention, the ultraviolet opaque base material film 110 may have an ultraviolet transmittance of 400 nm or less of 5% or less.

In the present invention, by using an ultraviolet-impermeable base film, it is possible to prevent the adhesive force from being lowered due to curing of the adhesive due to ultraviolet rays irradiated during the patterning and insulating film forming process described later.

The ultraviolet-impermeable base film may be prepared by using a resin containing an ultraviolet absorber, or by forming a coating layer containing an ultraviolet absorber on a base film.

Examples of the resin constituting the base film include a resin such as cyclo-olefin polymer (COP), polycarbonate, polyethylene terephthalate, polymethyl methacrylate, polyimide, polyethylene naphthalate, .

Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers, hydroxyphenyltriazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, etc. These may be used singly or in combination.

Examples of the benzotriazole ultraviolet absorber include 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole, benzenepropanoic acid and 3- (2H-benzotriazol- - (1,1-dimethylethyl) -4-hydroxy ester compound of (C ₇ to C ₉ branched and straight chain alkyl), octyl -3- [3-tert- butyl-4-hydroxy-5- (5 Yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazole 2-yl) phenyl] propionate, a mixture of 2- (2H-benzotriazol-2-yl) 4- (1,1,3,3-tetramethylbutyl) phenol, methyl-3- (3- (2H-benzotriazole- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol- (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) (2H-benzotriazole-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 4- (1,1,3,3-tetramethylbutyl) phenol], methyl-3- (3- (2H- 2- (2H-benzotriazol-2-yl) -6-dodecyl) -2,5-dihydroxyphenyl) propionate and polyethylene glycol 300, -4-methylphenol, 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimide-methyl) -5- methylphenyl] benzotriazole, 2,2'- 6- (benzotriazol-2-yl) -4-tert-octylphenol].

Examples of the hydroxyphenyltriazine based ultraviolet absorber include 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine-2-yl) (C ₁₀ to C _16, mainly C ₁₂ to C ₁₃ alkyloxy) methyl] oxirane in the reaction product, 2- (2,4-dihydroxyphenyl) -4,6-bis (2,4-dimethyl Phenyl] -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester, the reaction product of 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- - (dibutoxy) phenyl) -1,3,5-triazine, 2- (4,6-diphenyl-1,3,5-triazin- 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine.

Examples of the benzophenone ultraviolet absorber include 2-hydroxy-4-n-octyloxybenzophenone and the like.

Examples of the benzoate ultraviolet absorber include 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (TINUVIN 120) .

In one embodiment of the present invention, the pressure sensitive adhesive 150 may be a pressure sensitive adhesive commonly used in the art, to which a photopolymerizable compound and a photoinitiator are added. The pressure-sensitive adhesive imparts an adhesive force in the step of bonding the base film onto the carrier substrate, and the photopolymerizable compound and the photoinitiator are subjected to a photopolymerization reaction when the adhesive is irradiated with ultraviolet rays in the peeling step .

Specifically, the pressure-sensitive adhesive may include an acrylic copolymer and a crosslinking agent.

The acrylic copolymer may be a copolymer of a (meth) acrylate monomer having an alkyl group of 1-12 carbon atoms and a polymerizable monomer having a crosslinkable functional group.

Here, (meth) acrylate means acrylate and methacrylate.

Examples of the (meth) acrylate monomer having an alkyl group having 1-12 carbon atoms include n-butyl (meth) acrylate, 2-butyl (meth) acrylate, (Meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl Acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate and lauryl (meth) acrylate. These may be used singly or in combination.

The polymerizable monomer having a cross-linkable functional group is a component for imparting durability and cutability by reinforcing the cohesive force or adhesive strength of the pressure-sensitive adhesive composition by chemical bonding, and examples thereof include monomers having a hydroxy group and monomers having a carboxyl group, These may be used alone or in combination of two or more.

Examples of the monomer having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl Hydroxypropyleneglycol (meth) acrylate, hydroxyalkylene glycol having 2 to 4 carbon atoms in the alkylene group (e.g., methoxyethyl (meth) acrylate, Hydroxybutyl vinyl ether, 8-hydroxyoctyl vinyl ether, 9-hydroxynonyl (meth) acrylate, 4-hydroxybutyl vinyl ether, Vinyl ether, 10-hydroxydecyl vinyl ether, and the like.

Examples of the monomer having a carboxyl group include monovalent acids such as (meth) acrylic acid and crotonic acid; Dicarboxylic acids such as maleic acid, itaconic acid, and fumaric acid, and monoalkyl esters thereof; 3- (meth) acryloylpropionic acid; A succinic anhydride ring-opening addition adduct of 2-hydroxyalkyl (meth) acrylate in which the alkyl group has 2 to 4 carbon atoms, anhydrous succinic ring opening adduct of a hydroxyalkylene glycol (meth) acrylate having 2 to 4 carbon atoms in the alkylene group , And compounds obtained by ring-opening addition of succinic anhydride to a caprolactone adduct of 2-hydroxyalkyl (meth) acrylate in which the alkyl group has 2-3 carbon atoms.

The acrylic copolymer may further contain other polymerizable monomers other than the monomers in an amount not lowering the adhesive strength, for example, 10% by weight or less based on the total amount.

The method for producing the copolymer is not particularly limited and methods such as bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization which are commonly used in the art can be used, and solution polymerization is preferable. In addition, a solvent, a polymerization initiator, a chain transfer agent for molecular weight control and the like which are usually used in polymerization can be used.

The acrylic copolymer generally has a weight average molecular weight (polystyrene conversion, Mw) measured by gel permeation chromatography (GPC) of usually 50,000 to 2,000,000, preferably 400,000 to 2,000,000. When the weight-average molecular weight is less than 50,000, cohesion between co-polymers may be insufficient, which may cause problems in adhesion durability. If the weight average molecular weight is more than 2,000,000, a large amount of a diluting solvent may be required in order to ensure fairness in coating.

The crosslinking agent can be an isocyanate-based, epoxy-based, peroxide-based, metal chelating-based, oxazoline-based, or the like, which can improve adhesion and durability and can maintain reliability at high temperatures and maintain the shape of the pressure- One or more of them may be used in combination. Of these, an isocyanate-based compound is preferable.

Specifically, diisocyanate compounds such as tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, 2,4- or 4,4-diphenylmethane diisocyanate, and the like; And adducts of polyhydric alcohol compounds such as trimethylol propane of diisocyanate.

In addition to the isocyanate crosslinking agent, melamine derivatives such as hexamethylol melamine, hexamethoxymethyl melamine, hexabutoxymethyl melamine and the like; Polyepoxy compounds, for example, bisphenol A and epichlorohydrin condensate type epoxy compounds; At least one crosslinking agent selected from the group consisting of polyglycidyl ether of polyoxyalkylene polyol, glycerin di- or triglycidyl ether and tetraglycidyl xylylene diamine may be added and used together.

The photopolymerizable compound to be added to the pressure-sensitive adhesive is a component for reducing the peeling force of the pressure-sensitive adhesive by a photopolymerization reaction by irradiation of ultraviolet rays, and specifically polyfunctional acrylate may be used. Examples of polyfunctional acrylates include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri Acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate and urethane . These polyfunctional acrylates may be used alone or in combination of two or more.

The type of the photoinitiator is not particularly limited and includes, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, 2-methoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy- Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl- 2- -2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-ethyl anthraquinone, 2- , 2-aminoanthraquinone, thioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, Phenon dimethyl (1-methylvinyl) phenyl] propanone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine Pin oxide and the like. These photoinitiators may be used alone or in combination of two or more.

The pressure-sensitive adhesive may further contain various additives such as an antioxidant, a tackifier, an anti-aging agent, a filler, and a colorant in addition to the above components, if necessary.

1B, after the ultraviolet-impermeable base film 110 including the conductive layer 120 is bonded to the carrier substrate 200 with the adhesive 150 as described above, The conductive pattern layer 125 is formed.

Specifically, the conductive pattern layer 125 is formed by coating a photoresist on the conductive layer 120, drying, and then patterning using a photolithography process for exposing, developing, and etching.

1C, an insulating layer 130 is formed on the conductive pattern layer 125 to provide a flexible element 100. [

As the insulating film 130, an insulating resin such as polyimide, polyamide, polyamideimide, or the like can be used. Of these, polyimide is preferable from the standpoint of heat resistance and the like.

Various additives such as a leveling agent, a coupling agent, a defoaming agent and the like may be added to the resin constituting the insulating film within a range not lowering all the properties.

In an embodiment of the present invention, a composition including a resin and a photoinitiator constituting the insulating film may be coated on the conductive pattern layer 125, dried and cured to form the insulating film 130.

As the photoinitiator, the photoinitiator exemplified in connection with the adhesive may be used without limitation. Further, the same photoinitiator as that used in the pressure-sensitive adhesive may be used, or a different photoinitiator may be used.

Then, as shown in FIG. 1D, the flexible element 100 is peeled from the carrier substrate 200 by irradiating the adhesive 150 with ultraviolet rays in the direction of the carrier substrate to harden the adhesive.

In the method of manufacturing a flexible element according to an embodiment of the present invention, by using an ultraviolet-opaque base material film, the pressure-sensitive adhesive is not cured by ultraviolet rays irradiated for patterning of the conductive layer and for forming an insulating film, After the flexible element is formed, ultraviolet rays are irradiated in the direction of the carrier substrate to cure the pressure-sensitive adhesive, thereby enabling the flexible element to be easily peeled off from the carrier substrate by reducing the adhesive force due to curing shrinkage.

2 is a structural cross-sectional view of a flexible element manufactured by a method of manufacturing a flexible element according to an embodiment of the present invention. 2, a flexible device according to an embodiment of the present invention includes a transparent substrate layer 110, a conductive pattern layer 125 formed on the substrate film 110, and a conductive pattern layer 125 formed on the conductive pattern layer 125 (Not shown).

 In one embodiment of the present invention, the ultraviolet opaque base material film 110 may have an ultraviolet transmittance of 400 nm or less of 5% or less.

The ultraviolet-impermeable base film may be prepared by using a resin containing an ultraviolet absorber, or by forming a coating layer containing an ultraviolet absorber on a base film.

As the resin constituting the base film and the ultraviolet absorber, the same materials as described in the above-mentioned manufacturing method of a flexible element can be used.

In one embodiment of the present invention, the conductive pattern layer 125 is formed by patterning a conductive layer, and may be formed using a photolithography process or the like commonly used in the art.

The pattern of the conductive pattern layer 125 may be a regular pattern or an irregular pattern. The regular pattern may be a pattern pattern known in the art such as a mesh pattern. The irregular pattern is not particularly limited, but may be a boundary line shape of the Voronoi diagram.

As the material for forming the conductive layer, the same materials as those described in the above-described manufacturing method of a flexible element can be used.

In one embodiment of the present invention, the insulating layer 130 can be used without limitation as long as it is a nonconductive layer that can insulate the conductive pattern layer 125. Specifically, the same materials as described in the above-described method of manufacturing a flexible element can be used.

One embodiment of the present invention relates to a flexible display device provided with the flexible element.

The flexible display device is not limited as long as it is a display device including a flexible device. For example, the flexible display device may be a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode Diode (OLED), electrophoretic display (EPD), and the like.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Do. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

100: Flexible element
110: base film; 120: conductive layer
125: conductive pattern layer; 130: Insulating film
150: Adhesive
200: carrier substrate

Claims (16)

(I) bonding an ultraviolet-impermeable base film (110) comprising a conductive layer (120) on a carrier substrate (200) with an adhesive (150);
(Ii) patterning the conductive layer 120 to form a conductive pattern layer 125;
(Iii) providing an insulating layer (130) on the conductive pattern layer (125) to provide a flexible element (100); And
(Iv) removing the flexible element (100) from the carrier substrate (200) by irradiating ultraviolet rays to the pressure sensitive adhesive (150) in the direction of the carrier substrate to harden the pressure sensitive adhesive. The manufacturing method according to claim 1, wherein the carrier substrate is a glass substrate. The method of manufacturing a semiconductor device according to claim 1, wherein the ultraviolet-impermeable base film (110) including the conductive layer (120) is formed by bonding the ultraviolet- ≪ / RTI > The method according to claim 1, wherein the ultraviolet-impermeable base film (110) has an ultraviolet transmittance of 400 nm or less of 5% or less. The production method according to claim 1, wherein the ultraviolet light-impervious base film is produced using a resin containing an ultraviolet absorber. The production method according to claim 1, wherein the ultraviolet-impermeable base film is formed with a coating layer comprising an ultraviolet absorber on the base film. The manufacturing method according to claim 1, wherein the pressure-sensitive adhesive (150) is obtained by adding a photopolymerizable compound and a photoinitiator to the pressure-sensitive adhesive. The method according to claim 7, wherein the pressure-sensitive adhesive (150) comprises an acrylic copolymer, a crosslinking agent, a polyfunctional acrylate, and a photoinitiator. The manufacturing method according to claim 1, wherein the conductive layer (120) is patterned using a photolithography process. The manufacturing method according to claim 1, wherein the insulating layer (130) is formed on the conductive pattern layer (125) by coating a composition comprising a resin constituting the insulating layer and a photoinitiator, followed by drying and curing. A flexible device comprising an ultraviolet impermeable base film (110), a conductive pattern layer (125) formed on the base film (110), and an insulating film (130) formed on the conductive pattern layer (125). 12. The flexible device according to claim 11, wherein the ultraviolet-impermeable base film (110) has a ultraviolet transmittance of 400 nm or less of 5% or less. 12. The flexible element according to claim 11, wherein the ultraviolet light-impervious base film is produced using a resin containing an ultraviolet absorber. 12. The flexible element according to claim 11, wherein the ultraviolet-impermeable base film has a coating layer formed on the base film and including an ultraviolet absorber. A flexible display device comprising the flexible element according to any one of claims 11 to 14. The display device according to claim 15, wherein the flexible display device is a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED), or an electrophoretic display Display: EPD).

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