KR102302660B1 - Adhesive applied to display panel, display device including the adhesive and process of manufacturing the display device using the adhesive - Google Patents

Abstract

The present invention relates to an adhesive in which a compound having a movable molecule is introduced into a side chain of a binder resin, and a display device in which the adhesive is applied between a display panel and a structure. Since the movable molecules constituting the adhesive of the present invention can move along the linear molecules introduced into the binder resin, flexibility can be secured. Accordingly, the adhesive of the present invention has excellent external shock absorption and improved adhesion to an adherend, so that it can be used for bonding a display panel and a structure.

Description

Adhesive applied to a display panel, a display device including the same, and a manufacturing method thereof

The present invention relates to an adhesive applied to a display panel, and more particularly, to an adhesive having excellent shock absorption and adhesion, a display device including the adhesive, and a method of manufacturing a display device using the adhesive.

A flat panel display using a liquid crystal display (LCD) or an organic light emitting diode (OLED) instead of a conventional CRT is widely used in TV monitors and computer monitors as well as smartphones. These flat panel display devices basically include a display panel for displaying an image. For example, a liquid crystal display device includes a liquid crystal panel formed by bonding a liquid crystal layer between two opposing substrates as an essential component. An electric field is applied to the inside of the liquid crystal panel to change the alignment direction of liquid crystal molecules to induce a difference in transmittance. However, since the liquid crystal panel does not have a self-luminous element, a backlight unit including a light source while supporting the liquid crystal panel is disposed on the rear surface of the liquid crystal panel.

Recently, as the screen of the liquid crystal display becomes larger, research on reducing the weight and volume while having a large display area is being actively conducted. Accordingly, efforts are being made to reduce the weight and thickness of the liquid crystal display device by using a so-called borderless type backlight unit that reduces some components constituting the backlight unit. At the same time, the development of a liquid crystal display having a so-called narrow bezel that expands the display area and reduces the bezel area, which is a non-display area other than the display area, is being actively developed.

1 is a diagram schematically illustrating a conventional liquid crystal display device in which a borderless type backlight unit is attached to a liquid crystal panel while implementing a narrow bezel, excluding some components of the conventional backlight unit. The conventional liquid crystal display 10 includes a liquid crystal panel 20 , a backlight unit 30 , a main frame 40 , and a bottom frame 50 .

The liquid crystal panel 20 is a part that displays an image, and includes a first substrate 22 and a second substrate 24 that are face-to-face bonded with a liquid crystal layer (not shown) therebetween, and the first substrate 22 and the second substrate. It includes a first polarizing plate 26 and a second polarizing plate 28 respectively formed on the outer surface of the second substrate 24 .

Meanwhile, the backlight unit 30 supplies light to the liquid crystal panel 20 , and is disposed under the liquid crystal panel 20 to support the liquid crystal panel 20 . The backlight unit 30 includes a light emitting diode (LED) assembly (not shown) arranged along the longitudinal direction of at least one edge of the main frame 40 , and a reflector (not shown) disposed on the bottom frame 50 ; It includes a light guide plate 34 disposed on the reflecting plate (not shown), and a plurality of optical sheets (not shown) disposed on the light guide plate 34 .

Meanwhile, the main frame 40 is disposed on the light guide plate 34 , and the liquid crystal panel 20 is supported by the main frame 40 . In order to bond the liquid crystal panel 20 and the backlight unit 30 to each other, an adhesive 60 is applied to the upper surface of the main frame 40 .

In order to firmly bond the liquid crystal panel 20 and the backlight unit 30 to each other, the adhesive 60 must secure excellent adhesion to the adherend. As one method for securing strong adhesion to the adherend, there is a method of increasing the molecular weight of a binder resin, which is a main component of the adhesive 60 . In order to increase the molecular weight of the binder resin constituting the adhesive 60, it is necessary to increase the chain length of the binder resin. In this case, the viscosity of the binder resin increases. As a result of the increase in the viscosity of the binder resin, a discharge defect occurs in the nozzle used for coating the adhesive 60 on the upper surface of the main frame 40 . Accordingly, there is a problem in that heating discharging equipment is required, and thus fairness is deteriorated.

In addition, as the molecular weight of the binder resin increases, the modulus value increases, and thus flexibility is inevitably reduced. Therefore, as shown in FIG. 2, when an external force due to an external impact is applied, the high molecular weight, strong adhesive 60 does not disperse or relieve the stress generated by repulsion to the external shock, and the liquid crystal panel Apply the stress in (20). As such, the high molecular weight adhesive 60 has low absorbency to external impact, and thus stress due to external impact is applied to the liquid crystal panel 20 through the adhesive 60 . Due to the applied stress, refractive index anisotropy of the substrates 22 and 24 constituting the display panel 20 is caused, and a twist angle is formed in the liquid crystal structure of the liquid crystal layer (not shown), and the molecular arrangement of the liquid crystal is changed and light leakage occurs. do.

As a solution to this problem, a method of extending the chains constituting the low molecular weight binder resin and exhibiting strong adhesion to the adherend using the entanglement effect between the chains may be considered. However, when a low molecular weight binder resin having a low modulus value is used, since the bonding force between chains is weak, the cohesive force of the binder resin constituting the adhesive 60 is inevitably insufficient. As a result of insufficient cohesive force between the binder resins constituting the adhesive 60, when a stress such as a tensile force due to an external force occurs with respect to the adhesive 60 produced by chain extension constituting the low molecular weight binder resin, the extended chain the bond between them is broken For this reason, the bond between the adhesive agents 60 using the low molecular weight binder resin is broken, and the adhesive agent 60 is peeled from the liquid crystal panel 20 and the backlight unit 30 . As a result of the liquid crystal panel 20 being peeled off from the backlight unit 30 , the liquid crystal panel 20 is not firmly supported, and thus is vulnerable to external impact. Accordingly, the structure of the liquid crystal panel 20 and the molecular structure of the liquid crystal layer (not shown) constituting the liquid crystal panel 20 are deformed by external impact, resulting in light leakage.

As such, the adhesive 60 used for bonding the conventional liquid crystal panel 20 and the backlight unit 30 did not have both strong adhesion and flexibility at the same time. Due to this, it was not possible to satisfy the conflicting requirements of absorbing properties against external impact and strong adhesion. As a result, the liquid crystal panel 20 was deformed due to an external impact, resulting in a light leakage problem or peeling of the liquid crystal panel 20 .

SUMMARY OF THE INVENTION The present invention has been proposed to solve the problems of the prior art, and an object of the present invention is to provide an adhesive that satisfies both strong adhesion to an adherend and strong absorption against external impact, a display device to which the adhesive is applied, and the present invention. An object of the present invention is to provide a method for manufacturing a display device using an adhesive.

Another object of the present invention is to provide an adhesive having both low modulus properties and high toughness properties by securing fluidity due to external impact, a display device to which the adhesive is applied, and a method for manufacturing a display device using the adhesive. will do

According to one aspect of the present invention having the above object, the present invention includes a binder resin and a mobile compound introduced into a side chain of the binder resin, wherein the mobile compound is a cyclic molecule and a side chain of the binder resin Provided is an adhesive comprising a linear molecule introduced and penetrating the cyclic molecule, and a blocking group disposed at an end of the linear molecule to prevent separation of the cyclic molecule.

Illustratively, the cyclic molecule may be selected from the group consisting of cyclodextrin, cucurbituril and calixarene.

For example, the linear molecule includes a first linear molecule including a polyaminealkylene compound connected to the binder resin, and a second linear molecule connected to the first linear molecule through a urea bond and containing a polyoxyalkylene compound. It may contain molecules.

In this case, the cyclic molecule may be cross-linked with an adjacent cyclic molecule.

According to another aspect of the present invention, the present invention includes a display panel, a structure supporting the display panel, and an adhesive layer positioned between the display panel and the structure, wherein the adhesive layer includes a binder resin and a side chain of the binder resin and a mobile compound introduced into Disclosed is a display device including a blocking group for preventing separation of molecules.

In one exemplary embodiment, the display panel may be a liquid crystal panel, and the structure may be a backlight unit.

In another exemplary embodiment, the display panel may include an organic light emitting diode, and the structure may be a back cover.

According to another aspect of the present invention, the present invention includes applying an adhesive to one surface of a structure supporting a display panel, and bonding the display panel to the structure to which the adhesive is applied, wherein the adhesive is a binder resin. and a mobile compound introduced into a side chain of the binder resin, wherein the mobile compound includes a cyclic molecule, a linear molecule introduced into the side chain of the binder resin and penetrating the cyclic molecule, and the linear molecule Provided is a method of manufacturing a display device including a blocking group disposed at an end of the cyclic molecule to prevent separation of the cyclic molecule.

In the adhesive prepared according to the present invention, cyclic molecules can move through the linear molecules introduced into the binder resin, and a blocking group synthesized through a chain extension reaction is located at the ends of the linear molecules.

As the mobile molecules are introduced into the binder resin, the mobile molecules can move through the linear molecules with respect to an external shock, so flexibility can be secured and the shock absorption ability for external shocks is excellent. In addition, since the linear molecule was extended by the chain extension reaction, the space in which the ring molecule could move was expanded by the impact. Therefore, when an external force acts, by securing flexibility through the movement of ring molecules, it is possible to further improve the shock absorption ability for external shock.

In addition, it has a blocking group attached to the end of the linear molecule through a chain extension reaction. Due to the entanglement effect by the chain extension reaction, strong cohesive force to the binder resin can be secured, and thus the toughness of the adhesive can be improved, so that it is strong against external impact, and the adhesion to the adherend is improved. .

Accordingly, the adhesive of the present invention may be applied between, for example, a display panel constituting a display device and a structure supporting the display panel, thereby securely bonding the display panel and the structure. At the same time, stress due to an external force can be dispersed by the adhesive of the present invention, so that a problem of light leakage due to deformation of the display panel and components inside the display panel due to external impact or the like can be solved.

1 is a cross-sectional view schematically illustrating a liquid crystal display device using an adhesive as a method for bonding a conventional liquid crystal panel and a backlight unit.
2 is a diagram schematically illustrating a problem in that a display panel is deformed due to an external impact when a conventional adhesive is used.
3 is a schematic diagram schematically showing the structure of an adhesive in which a mobile compound is introduced into a binder resin according to an exemplary embodiment of the present invention.
4A to 4D are schematic diagrams schematically illustrating a process of manufacturing an adhesive in which a mobile compound is introduced into a binder resin, step by step, according to an exemplary embodiment of the present invention.
5 is an exploded perspective view schematically illustrating a coupling relationship between a liquid crystal panel and a backlight unit constituting a liquid crystal display according to the first embodiment of the present invention.
FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 5 .
7 shows that when the adhesive of the present invention is applied between the backlight unit and the liquid crystal panel constituting the liquid crystal display, which is the display device according to the first embodiment of the present invention, it is possible to prevent deformation of the liquid crystal panel by absorbing shock. It is a drawing that shows
8 is a cross-sectional view schematically illustrating a liquid crystal panel constituting a liquid crystal display, which is a display device according to the first embodiment of the present invention.
9 is a cross-sectional view schematically illustrating a form in which an adhesive of the present invention is positioned between a display panel and a back cover used in an organic light emitting diode display, which is a display device according to a second embodiment of the present invention; It shows that shock absorption is secured.
10 is a cross-sectional view schematically illustrating a display panel used in an organic light emitting diode display, which is a display device according to a second exemplary embodiment of the present invention.
11 is a graph showing the results of measuring the tensile stress according to the elongation of the adhesives prepared according to the exemplary embodiment and the comparative example of the present invention, respectively.

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

[glue]

In the adhesive of the present invention, a mobile compound having a cyclic molecule is introduced into the side chain of the binder resin to ensure flexibility. At the same time, in the adhesive of the present invention, the linear molecules constituting the mobile compound are connected to the binder resin, and the toughness of the adhesive is secured through the entanglement effect by the chain extension reaction at the ends of the linear molecules. Therefore, it can have excellent absorption properties for external impact and strong adhesion to the adherend. The adhesive of the present invention will be described first.

3 schematically shows the structure of an adhesive according to an exemplary embodiment of the present invention. As shown in Figure 3, the adhesive of the present invention is introduced into the binder resin and the side chain of the binder resin, it contains a cyclic molecule, a linear molecule, and a mobile compound including a blocking group.

As the binder resin, for example, any binder resin constituting a pressure sensitive adhesive (PSA) used in a display device may be used. In one exemplary embodiment, the binder resin may be a binder resin having good flexibility and having soft properties. For example, the binder resin constituting the adhesive according to the present invention may include an acrylic acid resin, a methacrylic acid resin, a (meth)acrylate resin, a urethane resin, a polysiloxane resin, and a copolymer thereof. Unless otherwise defined herein, the term “(meth)acrylate” is used to include both acrylate and (meth)acrylate. 3 illustrates, for example, a binder resin in the form of a block copolymer composed of a resin component A and a resin component B.

For example, since an acrylic acid resin, a methacrylic acid resin, a (meth)acrylate resin, and these copolymers have soft characteristics, the impact resistance by an external force is favorable. On the other hand, polyurethane constituting a copolymer of a urethane resin or a urethane resin and another resin is formed by a urethane bond obtained from a urethane prepolymer formed by addition polymerization reaction of a polyol having a hydroxyl group and an isocyanate group, and a reaction between water and isocyanate. The amine formed from the carbamic acid is reacted with an isocyanate and has a urea bond formed.

By controlling the relative amounts of the soft segment formed by the polyol used for synthesizing the urethane prepolymer and the hard segment formed by the isocyanate, an adhesive with secured flexibility can be obtained. In addition, after obtaining a urethane prepolymer to form a urethane bond, a moisture curing process is performed to prepare a binder resin having excellent adhesion.

The binder resin may be prepared from curable components such as monomers and/or oligomers constituting the resin through photocuring, moisture curing, and/or thermal curing processes. For example, acrylic acid resins, methacrylic acid resins, (meth)acrylate resins, and components constituting copolymers including these resins are substituted or unsubstituted acrylic acid, methacrylic acid, (meth)acrylate monomers and / Alternatively, it may be synthesized through crosslinking between these monomers and/or oligomers according to the curing of the oligomers.

In an exemplary embodiment, oligomers and/or monomers that are curable components for synthesizing acrylic acid resins, methacrylic acid resins and (meth)acrylate resins may be unsubstituted. _{Optionally, the curable component for synthesizing these resins may include one or more C 1} to C ₂₀ alkyl groups selected from methyl, ethyl, propyl, butyl, 2-ethylhexyl, octyl, decyl, dodecyl, lauryl, and the like; butadiene, hexadiene, octadiene, etc. at least one selected C ₂ ~ C ₂₀ alkenyl group; _{C 1} ~ selected from 1,4-butanediol, 1,6-hexanediol, ethylene glycol, ethylene glycol methyl ether, ethylene glycol phenyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, tetraethylene glycol, etc. C ₂₀ alkoxy group; C selected from one or more of 2-hydroxy-ethyl, 2-ethoxyethyl, 2-hydroxy-propyl, 2-hydroxy-butyl, 4-hydroxybutyl, 2-butoxyethyl, trimethoxybutyl, etc. ₁ ~ C ₂₀ alkoxyalkyl group; At least one C ₅ ~ C ₈ cycloalkyl group selected from cyclohexyl, dicyclopentanyl, isobornyl, etc., or at least one alicyclic group selected from N-acryloyl morphline, etc.; an epoxy group selected from epoxy, epoxycyclohexylmethyl, glycidyl, methylglycidyl, and the like; It may be substituted with an aryl group having 6 to 10 carbon atoms selected from at least one of benzyl, phenoxyethyl, 2-hydroxy-3-phenoxypropyl, and the like.

Meanwhile, a urethane prepolymer obtained by reacting a polyol with a diisocyanate to form a polyurethane bond constituting a copolymer of a urethane resin and a urethane resin and another resin may be used. Polyols for synthesizing urethane prepolymers include polyols obtained by reacting ethylene oxide or propylene oxide with glycerin, polyether polyols such as propylene glycol, tetramethylene glycol, and ethylene glycol polyether; and/or polycaprolactone polyol, polyester polyol obtained by dehydration condensation reaction of glycol or triol with adipic acid, which is a dibasic acid, and/or at least one kind may be selected. The diisocyanate compound for synthesizing the urethane prepolymer may be at least one selected from toluene diisocyanate (TDI), methylene diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), etc. . However, the polyols and diisocyanates used to form the polyurethane bond are not limited to the compounds described above.

Further, in order to form a polysiloxane bond constituting a polysiloxane resin and a copolymer of a polysiloxane resin and another resin, a monomer containing a silanol group and/or a monomer containing a siloxane group may be used. For example, the monomer containing a silanol group is an ethylenically unsaturated alkoxy silane such as a (meth)acrylate-based alkoxy silane; and/or an ethylenically unsaturated acyloxysilane including an ethylenically unsaturated acetoxysilane such as (meth)acrylate-based acetoxysilane or (meth)acrylatetopropyltriacetoxysilane.

In addition, the monomers containing siloxane groups particularly include compounds having linear siloxane groups. For example, the monomer compound having a linear siloxane group includes mono/di/tri/tetra/hexa/octasiloxane substituted with an alkyl group having 1 to 10 carbon atoms; mono/di/tri/tetra siloxane substituted with an alkoxy group having 1 to 4 carbon atoms; One or more types of alkylalkoxysilanes having 1 to 10 carbon atoms, vinylalkoxysilanes, aminoalkylalkoxysilanes, silanes substituted with methacryloxy groups or mercaptoalkyl groups are included, but the present invention is not limited thereto.

Polysiloxane can be obtained by thermosetting or photocuring a monomer for synthesizing polysiloxane. Illustratively, the unit units constituting the polysiloxane may be connected in a straight line form or may be connected in a cage form. Optionally, the polysiloxane may be in the form of a silsesquioxane.

When the binder resin is synthesized by photocuring, a photoinitiator is included in the liquid adhesive composition to induce a polymerization reaction of the curable component constituting the binder resin. For example, as the photoinitiator, any photoinitiator capable of inducing a photopolymerization reaction by irradiation of an appropriate power source such as UV may be used. For example, commercial photoinitiators may be used, which may consist of Irgacure 184, Irgacure 819, and combinations thereof, although the photoinitiators that may be used in accordance with the present invention are by no means limited to these products.

For example, as a usable photoinitiator, an acetophenone-based photoinitiator, a benzophenone-based photoinitiator, a thioxanthone-based photoinitiator, a benzoin-based photoinitiator, a triazine-based photoinitiator, and a phosphine oxide-based photoinitiator may be used. For example, phenylbis(2,4,6-trimethylbenzoyl-phosphine oxide) photoinitiator induces polymerization initiation reaction at a long wavelength such as 405 nm, increases deep hardenability, and inhibits surface hardening to spread throughout the adhesive. A uniform cross-link can be formed throughout.

The photoinitiator may be included in a proportion of 0.01 to 3.0 parts by weight in the liquid adhesive composition. If the content of the photoinitiator is less than 0.01 parts by weight, the curing reaction rate is too slow or does not perform the initiation role, resulting in poor curing efficiency. If the content of the photoinitiator exceeds 3.0 parts by weight, yellowing may occur due to the ring structure characteristics of the photoinitiator that did not participate in curing.

On the other hand, the adhesive of the present invention includes a mobile compound introduced into the side chain of the binder resin. For example, the mobile compound is grafted to the side chain of the binder resin. In an exemplary embodiment, the mobile compound comprises a ring molecule, a linear molecule through which the cyclic molecule passes, and a blocking group located at the end of the linear molecule to prevent escape of the cyclic molecule. group) may be a similar rotaxane compound.

The linear molecule constituting the mobile compound may be linked to the side chain of the binder resin through, for example, an amide bond, a urethane bond, an ether bond, a urea bond, or an ester bond. The functional group connecting the linear molecule and the binder resin may be determined depending on the type of the substituent formed on the binder resin and the linear molecule, or the type of compound used for the reaction between the binder resin and the linear molecule.

For example, a (meth)acrylate group, an amine group, an isocyanate group, a hydroxyl group, a linear molecule containing at least one carboxyl group, and a (meth)acrylate group formed in the binder resin, a silane group, a hydroxyl group, an isocyanate group, or In the case of reacting the carboxyl group, the linear molecule may be directly connected to the binder resin, or may be connected to the binder resin through an amide bond, a urethane bond, an ether bond, a urea bond, or an ester bond.

In an exemplary embodiment, the linear molecule may have a polyalkylene group, or may have a polylactone group. For example, as a linear molecule, a polyalkylene-based, polyoxyalkylene-based, or polyaminealkylene-based compound containing repeating units of alkylene, oxyalkylene, or aminealkylene having 1 to 10 carbon atoms and/or a compound having 3 to 10 carbon atoms A polylactone-based compound having a lactone-based repeating unit may be used.

Optionally, the linear molecule is a polyalkylene, polyoxyylene or polyaminealkylene or polylactone compound directly or via an amide bond, a urethane bond, an ether bond, a urea bond or an ester bond, etc. linked to the binder resin. The first linear molecule and the first linear molecule are linked through a urethane bond, a urea bond, an amide bond, an ester bond, an ether bond, etc. It may contain two linear molecules. For example, the first linear molecule may be a polyaminealkylene-based compound, and the second linear molecule may be a polyoxyalkylene-based compound connected to the first linear molecule through a urea bond. By using a linear molecule having a sufficient length, it is possible to form sufficient space for the cyclic molecule to move.

The linear molecules that make up the mobile compound penetrate the cyclic molecules. A cyclic molecule can move along a linear molecule, and separation is prevented by a blocking group located at an end of the cyclic molecule. As the cyclic molecule, any compound having an interior space sufficient to penetrate or surround the linear molecule may be used. If necessary, the cyclic molecule may include a functional group such as a hydroxyl group, an amino group, a carboxyl group, a thiol group, an aldehyde group, or the like. Optionally, a compound having a curable ethylenic double bond, such as a (meth)acrylate group, may be introduced at the end of the cyclic molecule. In exemplary embodiments, the cyclic molecule comprises cyclodextrin, cucurbituril or calixarene.

In an exemplary embodiment, some cyclic molecules, such as cyclodextrins, may be composed of polyoxyalkylene compounds such as polyethylene glycol, or complexes with oligooxyalkylene compounds such as oligoethylene glycol. Since the oxyalkylene compound may constitute a part of a linear molecule, if a cyclic molecule forming a complex with these oxyalkylene compounds is used, there is an advantage in that the movement space of the cyclic molecule can be expanded.

Cyclodextrin, an example of a cyclic molecule, can be obtained from carbohydrates such as starch by the action of enzymes. -glucopyranoside) units are linked 1->4. For example, the cyclodextrin that can be used according to the present invention may have 5-8 alpha-D-glucopyranoside units. In particular, preferably, cyclodextrins usable as porous supramolecules include α-cyclodextrin (consisting of 6 sugar rings), β-cyclodextrin (consisting of 7 sugar rings), and γ-cyclodextrin (consisting of 8 sugar rings). composition).

Cucurbituril, another example of a cyclic molecule, is a porous supramolecule composed of glycouril (=C ₄ H ₂ N ₄ O _{2 =) linked by a methylene bridge (-CH 2 -).} Cucurbituril is named cucurbit[n]uril according to the number (n) of glycouryl units, which are structural units. Cucurbituril that can be incorporated into the binder resin according to the present invention is cucurbituril having 4-20 glycouril units (i.e. cucurbit[4-20]uril), preferably 5-10 glycouril units. cucurbituril (ie cucurbit[5-10]uril).

Another example of a cyclic molecule, a calixarene compound, is a goblet-shaped macrocyle or cyclic oligomer compound containing a benzene ring. Calixarene is formed by hydroxyalkylation of phenol, resorcinol, and pyrogallol, which are benzene compounds substituted with a hydroxyl group, and an aldehyde. A benzene ring substituted with a hydroxyl group bridges a methylene group. It is composed of unit units. According to the number of these unit units, it is named calix [p] arene (p is the number of unit units). In an exemplary embodiment, the calixarenes used as the porous supramolecules are calixarenes or derivatives thereof having 3 to 10 unit units (ie, calix[3-10]arenes and derivatives thereof).

In an alternative embodiment, a compound having a photocurable ethylenic double bond at the terminus of the cyclic molecule, which may be, for example, a cyclodextrin may be incorporated. When a compound having a photocurable ethylenic double bond is introduced at the end of the cyclic molecule, when the cyclic molecule is inserted into the linear molecule, cross-linking between the cyclic molecules inserted into the adjacent linear molecule by the photocuring reaction can be formed. For example, the compound having a photocurable ethylenic double bond substituted at the terminal of the cyclic molecule may be a (meth)acrylate-based compound.

In one exemplary embodiment, the (meth)acrylate-based compound may be linked directly to the terminus of the cyclic molecule. Alternatively, the cyclic molecule and the (meth)acrylate-based compound may be connected through a urethane bond, an ester bond, an ether bond, or the like. As one method for forming an appropriate bond between a cyclic molecule and a (meth)acrylate-based compound, a (meth)acrylate-based compound having a hydroxyl group, a halogen group, a carboxyl group and/or an isocyanate group is reacted with a cyclic molecule. can As another method, the cyclic molecule is first reacted with a compound containing at least two hydroxyl groups, halogen groups, carboxyl groups and/or isocyanate groups, and then a (meth)acrylate compound having at least one hydroxyl group or carboxyl group is used. can

By including a compound having a photocurable ethylenic double bond at the terminal of the cyclic molecule, a crosslink between the cyclic molecules inserted into adjacent linear molecules can be formed. When a cross-link is formed between cyclic molecules that are mobile molecules, the cross-linking point is fluidly changed as the mobile molecule moves along each linear molecule by impact. Therefore, compared to the case where crosslinks are formed between conventional molecules that cannot move, when crosslinks are formed between cyclic molecules, which are mobile molecules, flexibility is improved, resulting in a low modulus value despite crosslinking. can have In addition, the cohesive force is improved by crosslinking between the mobile molecules, thereby improving the adhesion to the substrate.

On the other hand, a blocking group is positioned at the end of the linear molecule (ie, opposite to the binder resin) to prevent the cyclic molecule from leaving. Molecules constituting the blocking group have a bulky structure, so that cyclic molecules cannot pass through.

In an exemplary embodiment, prior to formation of a blocking group at the end of the first linear molecule, a suitable compound, for example, a polyalkylene-based, polyoxy-containing alkylene, oxyalkylene or aminealkylene repeating unit having 1 to 10 carbon atoms A second linear molecule such as an alkylene-based compound and a polyamine-alkylene-based compound or a compound having a polylactone-based compound having a lactone-based repeating unit having 3 to 10 carbon atoms may be used.

In an alternative embodiment, when polyalkylenediamine is used as the first linear molecule incorporated into the binder resin, one or more hydroxyl groups, carboxy groups and / or a second linear molecule having an isocyanate group may be connected to the first linear molecule by a urethane bond, a urea bond, an ester bond, an ether bond, an amide bond, or the like. If necessary, an appropriate chain extender may be added for chain extension of the second linear molecule, and the second linear molecule may be extended through a plurality of polyoxyalkylene bonds.

In an exemplary embodiment, in order to form a second linear molecule, ethylene oxide having an alkylene group having 1 to 20 carbon atoms or a polyol obtained by reacting propylene oxide with glycerin, such as propylene glycol, tetramethylene glycol, ethylene glycol polyether polyether polyols; and/or polycaprolactone polyol, polyester polyol polyol obtained by dehydration condensation reaction of glycol or triol with adipic acid, which is a dibasic acid; Polycarboxylic acids and/or polyisocyanates such as toluene diisocyanate (TDI), methylenediphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) or cyanurate can be used. However, the present invention is by no means limited thereto.

In an exemplary embodiment, the blocking group may be a polymer having a urethane bond. For example, using a polyisocyanate that reacts with an amine exposed to a polyalkyleneamine used as the first linear molecule to form a urea linkage, adding an excess of a chain extender that reacts with the exposed isocyanate group, A second linear molecule extending with alkylene can be obtained. At the same time, according to the chemical reaction between the remaining isocyanate group and the excess chain extender, a molecule having polyurethane as a blocking group can be obtained.

In addition, optionally, the blocking group may be porphyrin, a metal complex such as a cobalt complex having an amine group as a ligand or an iron complex having a cyanide as a ligand, or a compound such as biphenyl, bipyridinium, or trinitrobenzene.

Optionally, the adhesive of the present invention may include other functional additives. Functional additives that can be used are plasticizers, surfactants and the like. The plasticizer component is for adjusting the modulus value of the adhesive. Plasticizer components that may be used include any component capable of lowering the modulus value of the adhesive. For example, as a plasticizer component, dioctyl phthalate (DOP)-based, dioctylamiphate (DOA)-based, tricresyl phosphate (TCP), dioctylazolate (DOZ)-based, ester (Esther)-based, polyisoprene-based and combinations thereof. The plasticizer component may be added in the adhesive in a proportion of, for example, 1 to 3 parts by weight.

The surfactant is a component that improves the adhesion between the adhesive and the substrate of the present invention. The type of usable surfactant is not particularly limited, and one or two or more types of nonionic surfactants, cationic surfactants, anionic surfactants and silicone surfactants may be used in combination. For example, the surfactant may be added in an amount of 0.1 to 3 parts by weight in the adhesive.

Optionally, in order to improve the storage properties of the adhesive of the present invention, at least one selected from anionic stabilizers, radical stabilizers, and curing accelerators may be added. The stabilizer may be added in an amount of 0.1 to 3 parts by weight in the adhesive.

The adhesive of the present invention improves flexibility because a low modulus value can be secured because a cyclic molecule, which is a mobile molecule, can move along a long linear molecule connected to the binder resin and the side chain of the binder resin. Therefore, when an external impact is applied to the display device to which the adhesive of the present invention is applied, the cyclic molecules can absorb the impact while moving through the linear molecules introduced into the binder resin, and thus have excellent shock absorption properties. In addition, due to the entanglement effect of the linear molecules according to the chain extension reaction with respect to the linear molecules, the linear molecules can be strongly aggregated in the binder resin, thereby securing toughness. Therefore, it is possible to obtain improved adhesion properties to the adherend.

Subsequently, a process of manufacturing an adhesive including a binder resin and a mobile compound introduced into the binder resin according to an exemplary embodiment of the present invention will be described with reference to FIGS. 4A to 4D . First, as shown in 4a, the main chain of the binder resin may be formed by photocuring a curable component having a carboxylic acid group as a substituent. For example, in FIG. 4A, A represents an unsubstituted or substituted acrylic acid unit unit, and B represents an unsubstituted or substituted methacrylic acid unit unit. Preferably, it is made to form a block copolymer with methacrylic acid rather than using acrylic acid alone, so that a sufficient space for linear molecules to be introduced into the side chain of the binder resin can be formed.

While curing the curable component, an excess of polyalkylenediamine, for example, polyhexamethylenediamine, is added to prepare a binder resin in which polyhexamethylenediamine is introduced as a first linear molecule in the carboxylic acid formed in the binder resin. _{(R 1} in FIG. 4A represents a polyalkylene group. For example, polyalkylenediamine may be added in a molar ratio of 0.5 to 2.0 with respect to the curable component, but the present invention is not limited thereto.

After the first linear molecule is introduced into the side chain of the binder resin, as shown in FIG. 4B, for example, when alpha cyclodextrin, a cyclic molecule forming a complex form with polyethylene glycol, is added, the cyclic molecule becomes the first linear molecule. It can be formed in a form that surrounds the molecule. Since a long linear molecule is introduced into the side chain of the binder resin, sufficient space is not formed in the main chain of the binder resin. .

In an exemplary embodiment, a compound having a photocurable ethylenic double bond, such as a (meth)acrylate-based compound, is introduced at the end of the cyclic molecule. Therefore, by adding a photoinitiator together with a cyclic molecule, crosslinks can be formed through a photocuring reaction between cyclic molecules inserted into adjacent linear molecules among a plurality of linear molecules introduced into the side chain of the binder resin.

A blocking group is then formed at the end of the first linear molecule surrounded by the cyclic molecule. For example, a compound capable of reacting with an amine group formed at an end of the first linear molecule surrounding the cyclic molecule may be used to link the second linear molecule. For example, a compound having a plurality of isocyanate groups as a functional group capable of reacting with an amine group may be used. Illustratively, in FIG. 4C , a compound having a plurality of isocyanate groups was used to _{react with an amine group of the first linear molecule (R 1} ) to form a urea bond. The polyisocyanate compound capable of reacting with the amine group positioned at the end of the first linear molecule is toluene diisocyanate (TDI, for example 2,4-TDI or 2,6-TDI), methylenediphenyl diisocyanate ( hexamethylene diisocyanate ( aliphatic or cycloaliphatic isocyanates such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), or polymethylenepolyphenylpolyisocyanate, cyanurate, and derivatives and combinations thereof, The present invention is not limited thereto. Accordingly, a second linear molecule represented by _{R 2} may be formed through the urea bond formed at the end of the first linear molecule represented by _{R 1 .} For example, the polyisocyanate compound may be added in the same molar ratio as the amine groups at the ends constituting the first linear molecule.

Subsequently, as shown in FIG. 4D , _{the reactive isocyanate group formed at the end of the second linear molecule (R 2} ) is removed and the second linear molecule is lengthened to secure sufficient flexibility, a chain extender (chain extender) extender) and/or a crosslinking agent. Chain extenders and/or crosslinking agents that can be used include diols such as ethylene glycol, propylene glycol, 1,4-butanediol, and polytetramethylene glycol; triols such as glycerin and trimethylolpropane; tetraols such as pentaerythritol; diamines such as oxypropylated ethylenediamine, hexamethylenediamine, and m-phenylenediamine; At least one type may be selected from alcohol amines such as diethanolamine or triethanolamine.

Illustratively, if a polyalkylenediol such as 1,4-butanediol is added as a chain extender, a second linear molecule composed of polyoxyalkylene may be obtained by a chain extension reaction of the polyalkylenediol. Since the length of the entire linear molecule can be lengthened by the chain extension reaction, the movement space of the cyclic molecule can be expanded.

In addition, if an excess of a chain extender is added with respect to the remaining isocyanate groups, the urethane prepolymer formed while reacting with the isocyanate groups to form an Allophanate and Biuret structure may be crosslinked, resulting in an entanglement effect. For example, the polyalkylenediol used as the chain extender may react with the remaining isocyanate group of the polyisocyanate compound to form a urea bond with the end of the first linear molecule to form a three-dimensional crosslinked urethane bond. Since the cross-linked polyurethane compound and/or the extended chain is a fairly bulky molecule, it is possible to form a blocking group to prevent separation of the cyclic molecule. In order to form crosslinks due to chain extension and entanglement effect, for example, the chain extender may be added in a molar ratio of 5 to 20 with respect to the isocyanate groups remaining in the polyisocyanate compound linked to the first linear molecule, but the present invention is not limited thereto. not limited

According to an exemplary embodiment, the adhesive of the present invention using a copolymer of acrylic acid and methacrylic acid as a binder resin may be represented by the following formula (I).

(In formula (I), R ₁ and R ₂ are each independently polyalkylene containing 1 to 10 carbon atoms or oxyalkylene repeating units or polylactones having 3 to 8 carbon atoms and lactone repeating units. R ₃ to R ₇ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkyl group having 1 to 20 carbon atoms, cyclo having 5 to 8 carbon atoms selected from the group consisting of an alkyl group, an epoxy group, and an aryl group having 6 to 10 carbon atoms; R ₈ is a methyl group; m and n are the number of repeating units of acrylic acid and methacrylic acid, respectively, and are integers between 1 and 10000)

In an exemplary embodiment, a liquid adhesive in which a curable component and a non-curable component such as a photoinitiator and other additive components are mixed is coated onto a suitable substrate, such as a structure supporting a display panel. The method of applying this liquid adhesive on the substrate is a method such as spin coating such as a central drop spin method, roll coating, spray coating, bar coating, slit coating using a slit nozzle such as ejection nozzle type coating, or a dispensing method. and two or more methods may be combined. The liquid adhesive coated on the substrate may be cured using a light source, for example, a light source emitting light of an ultraviolet wavelength, such as an LED lamp.

[display device]

Next, a display device to which the adhesive according to the present invention is applied will be described. 5 is an exploded perspective view schematically illustrating a coupling relationship between components constituting a liquid crystal display according to the first embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 5 . The liquid crystal display device 100 as a display device according to the first embodiment of the present invention includes a liquid crystal panel 120 , a backlight unit 130 which is a structure supporting the liquid crystal panel 120 , and a main frame 140 . , including a bottom frame (150) and an adhesive layer (160).

The liquid crystal panel 120 for displaying an image includes a first substrate 122 and a second substrate 124 that are bonded face to face with a liquid crystal layer 125 (refer to FIG. 8 ) interposed therebetween. The gate printed circuit board and the data printed circuit board (not shown) are connected along at least one edge of the liquid crystal panel 120 via a connecting member (not shown) such as a flexible circuit board, so that the side surface of the main frame 140 in the modularization process Or, it is in close contact with the rear surface of the bottom frame 150 . First and second polarizing plates 126 and 128 are respectively formed on the outer surfaces of the first and second substrates 122 and 124 .

A backlight unit 130 , which is a structure supporting the liquid crystal panel 120 while supplying light, is disposed on the rear surface of the liquid crystal panel 120 so that the difference in transmittance displayed by the liquid crystal panel 120 is expressed to the outside. The backlight unit 130 includes a light emitting diode assembly 138 arranged along the longitudinal direction of at least one edge of the main frame 140 , a white or silver reflecting plate 136 , and a light guide plate disposed on the reflecting plate 136 . 134 and an optical sheet 132 disposed on the light guide plate 134 .

The light emitting diode assembly 138 is a light source of the backlight unit 130 and is located on one side of the light guide plate 134 to face the light incident surface of the light guide plate 134, and the light emitting diode assembly 138 includes a plurality of light emitting diodes ( 138a) and a printed circuit board 138b on which a plurality of light emitting diodes 138a are mounted to be spaced apart from each other by a predetermined interval.

The light guide plate 134 on which the light emitted from the plurality of light emitting diodes 138a is incident, the light incident from the plurality of light emitting diodes 138a proceeds through the light guide plate 134 by total reflection several times. It spreads evenly over a wide area to provide a surface light source to the liquid crystal panel 120 .

The light guide plate 134 may include a pattern having a specific shape on the rear surface of the light guide plate 134 to supply a uniform surface light source. For example, the pattern of the light guide plate 134 may include an elliptical pattern, a polygon pattern, a hologram pattern, etc. to guide the light incident into the light guide plate 134 . In addition, such a pattern may be formed on the lower surface of the light guide plate 134 by a printing method or an injection method.

The reflection plate 136 is located on the rear surface of the light guide plate 134 , and reflects the light passing through the rear surface of the light guide plate 134 toward the liquid crystal panel 120 to improve the luminance of the light. The plurality of optical sheets 132 on the light guide plate 134 include a diffusion sheet and at least one light collecting sheet, and the light passing through the light guide plate 134 is diffused or condensed to form a more uniform surface to the liquid crystal panel 120 . Let the light source be incident.

The liquid crystal panel 120 and the backlight unit 130 are modularized through the main frame 140 , the bottom frame 150 , and the adhesive layer 160 . The bottom frame 150 on which the backlight unit 130 is seated includes a horizontal plane that is the basis for assembling the entire structure constituting the liquid crystal display 100 , and an edge part whose edge is vertically bent. The main frame 140 having a rectangular frame shape includes a side wall portion 140a surrounding a side surface of the backlight unit 130 such as a side surface of the light guide plate 134 and a rear surface of the printed circuit board 138b, and a side wall portion 140a ) and includes a support portion 140b bent from the light guide plate 134 and disposed on the upper edge of the backlight unit 130 , and is coupled to the bottom frame 150 . The main frame 140 is also referred to as a support main, a guide panel or a main support, and a mold frame, and the bottom frame 150 is also referred to as a cover bottom, a bottom cover, or a lower cover. The main frame 140 and the bottom frame 150 may be made of a material such as polycarbonate (PC), aluminum, stainless steel, and electrolytically galvanized steel (EGI), but may be made of other materials. .

The liquid crystal display 100 includes a display area DR substantially used for image display and a non-display area NDR surrounding the display area DR, and a non-display area called a bezel area. NDR may be defined as a region in which light from the backlight unit 130 is not supplied to the liquid crystal panel 120 by the support part 140b of the main frame 140 . In addition, the liquid crystal panel 120 is fixed to the support portion 140b of the main frame 140 and the edge is supported. For this purpose, an adhesive layer 160 is provided between the liquid crystal panel 120 and the support portion 140b of the main frame 140 . this is formed

The adhesive layer 160 serves to fix the liquid crystal panel 120 to the support portion 140b of the main frame 140 , and the adhesive according to the present invention is applied to four sides of the support portion 140b or four sides of the liquid crystal panel 120 . By continuously applying it to the sides, it can be formed on the main frame 140 between the liquid crystal panel 120 and the backlight unit 130 . For example, since the adhesive layer 160 may be formed to a width of about 2.0 mm or less, the non-display area NDR may be reduced to a width of about 5.0 mm or less, and a narrow bezel liquid crystal display may be formed. The device 100 may be manufactured.

If necessary, the adhesive layer 160 may be formed using a functional adhesive having a relatively high adhesive strength and a black color, and thus the liquid crystal display 100 with improved display quality by preventing light leakage at the corners. can do. Illustratively, the adhesive layer 160 of the present invention is composed of a binder resin, a mobile compound introduced into the binder resin, and a cyclic molecule, a linear molecule through which the cyclic molecule passes, and a blocking group that prevents separation of the cyclic molecule. do. Therefore, by using the adhesive layer 160 to which the adhesive according to the present invention is applied, it is possible to solve the problems of the conventional adhesive.

The adhesive layer 160 of the present invention has elasticity by securing flexibility because cyclic molecules can move along the long linear molecules introduced into the side chain of the binder resin. Accordingly, as shown in FIG. 7 , when an external force generated outside and/or inside the display device is applied to the adhesive layer 160 , the adhesive layer 160 disperses and relieves stress, and thus the liquid crystal panel 120 . do not apply stress with As such, since the adhesive layer 160 of the present invention has good impact resistance and does not apply stress to the liquid crystal panel 120 , light leakage due to deformation of the liquid crystal panel 120 due to an external force can be prevented. In addition, linear molecules are introduced into the side chain of the binder resin, and have sufficient cohesion through the entanglement effect according to the chain extension reaction of the introduced linear molecules. That is, since the adhesive of the present invention has better toughness than a simple binder resin, it has excellent impact resistance and secures strong adhesion to the substrate.

The liquid crystal panel 120 bonded through the backlight unit 130 and the main frame 140 according to the first embodiment of the present invention will be described in detail with reference to FIG. 8 .

In the liquid crystal panel 120 constituting the liquid crystal display device 100 , a first substrate 122 and a second substrate 124 face each other and face each other, and a liquid crystal layer 125 is disposed between the substrates 122 and 124 . ) is included. The first substrate 122 and the second substrate 124 may be made of a glass material, but may be illustratively a flexible substrate made of a plastic material such as a flexible material, for example, a polyimide material. have. In this case, the liquid crystal panel 120 may function as a flexible display panel. Although not shown, an alignment film for determining the initial molecular arrangement direction of liquid crystal is formed at the boundary between the liquid crystal layer 125 of the first substrate 122 and the second substrate 124 of the liquid crystal panel 120, and is filled therebetween. A seal pattern is formed along the edges of the first substrate 122 and the second substrate 124 to prevent leakage of the liquid crystal layer 125 .

Looking in more detail with respect to the plurality of electrodes and wires stacked on the first substrate 122 , a plurality of gate wires (not shown) extend in one direction on the upper portion of the first substrate 122 . A plurality of data lines 170 are formed in the second direction to define a plurality of pixel regions P by crossing a gate line (not shown). A gate pad (not shown) is formed in the non-display area by being connected to one end of the gate line (not shown), and a data pad (not shown) is formed in the non-display area by being connected to one end of the data line 170 . .

In each of the plurality of pixel regions P, a semiconductor layer 174 including a gate electrode 171 , a gate insulating layer 173 , an active layer 174a , an ohmic contact layer 174b , and source and drain electrodes 176 . , 177) is formed with a thin film transistor Tr. The gate electrode 171 is connected to a gate line (not shown) and is formed on the first substrate 122 . A gate insulating layer 173 made of an inorganic insulating material, for example, silicon oxide (SiOx) or silicon nitride (SiNx), is formed on the gate wiring (not shown) and the gate electrode 171 .

An active layer 174a made of pure amorphous silicon is formed on the gate insulating layer 173 , and an ohmic contact layer 174b formed on the active layer 174a to expose the center of the active layer 174a and made of impurity amorphous silicon is formed. has been The active layer 174a and the ohmic contact layer 174b form a semiconductor layer 174 .

A source electrode 176 and a drain electrode 177 are formed on the semiconductor layer 174 to be spaced apart from each other to expose the center of the active layer 174a. The source electrode 176 is positioned on the semiconductor layer 174 and extends from the data line 170 , and the drain electrode 177 is positioned on the semiconductor layer 174 to be spaced apart from the source electrode 176 . The thin film transistor Tr is positioned in the switching region TrA.

In addition, a data line 170 extending in the second direction is formed on the gate insulating layer 173 to cross the gate line (not shown). The data line 170 extends from the source electrode 176 of the thin film transistor Tr positioned in the pixel region P. Meanwhile, although not shown in the drawings, in one exemplary embodiment, a common wiring (not shown) is formed along the second direction parallel to the data line 170 on the gate insulating layer 173 , and the gate wiring (not shown) ) intersect with In an alternative embodiment, the common wiring (not shown) may be formed on the same layer as the gate wiring (not shown) in parallel to the gate wiring (not shown).

Meanwhile, a first protective layer 178a covering the data line 170 , the source electrode 176 , the drain electrode 177 , and the common line (not shown) is formed. A drain contact hole 179 exposing the drain electrode 177 of the thin film transistor Tr is formed in the first passivation layer 178a. The first passivation layer 178a may be made of an inorganic material such as silicon oxide or silicon nitride, or an organic material such as photoacrylic. The first passivation layer 178a prevents the ohmic contact layer 174b from being damaged in the process of forming the pixel electrode 182 .

In addition, in each pixel region P, the pixel electrode 182 as a first electrode electrically connected to the drain electrode 177 of the thin film transistor Tr through the drain contact hole 179 is provided as a first protective layer. It is formed on (178a). The pixel electrode 186 is made of a transparent conductive material, and may have a plate shape in each pixel region P. For example, the transparent conductive material may be indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). Although not shown in the drawings, a gate pad electrode and a data pad electrode made of the same transparent conductive material as the pixel electrode 182 are formed in the non-display area on the upper portion of the first passivation layer 178a. It is electrically connected to the gate pad through a pad contact hole (not shown), and the data pad electrode is electrically connected to the data pad through a data pad contact hole (not shown).

A second passivation layer 178b is formed on the pixel electrode 182 . Like the first passivation layer 178a, the second passivation layer 178b may be made of an inorganic material such as silicon oxide or silicon nitride, or an organic material such as photoacrylic.

Meanwhile, a common electrode 186 overlapping the plate-shaped pixel electrode 182 and having a plurality of slit-shaped holes (openings) 187 is formed on the second passivation layer 178b. Like the pixel electrode 182 , the common electrode 186 serving as the second electrode may be made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). The common electrode 186 is formed over the entire display area in which the plurality of pixel areas P are formed. When a voltage is applied between the pixel electrode 182 , which may be a plate-shaped first electrode, and the common electrode 186 , which may be a second electrode having an opening 187 , a fringe field is formed so that the liquid crystal is formed. By driving, the transmission efficiency is improved and a high-quality image is displayed.

Although not shown in the drawings, a black matrix, which is a light blocking member having an opening corresponding to each pixel region P, is formed under the second substrate 124 constituting the color filter substrate, and is formed between the lower portion of the black matrix and the black matrix. A color filter layer is formed under the second substrate 124 exposed through the opening. The color filter layer (not shown) includes red, green, and blue color filters corresponding to the pixel area P. In addition, between the color filter layer (not shown) and the liquid crystal layer 125, an overcoat layer (not shown) made of a material such as polyimide, polyacrylate, polyurethane, etc. is provided to protect the color filter layer (not shown) and to planarize the surface. more can be formed.

Meanwhile, although the structure in which the liquid crystal panel and the backlight unit are bonded as a structure has been described in the first embodiment, the adhesive of the present invention may be applied between another display panel and a structure supporting the panel. 9 is a cross-sectional view schematically illustrating a form in which an adhesive of the present invention is positioned between a back cover as a structure and a display panel used in an organic light emitting diode display according to a second embodiment of the present invention.

As schematically shown in FIG. 9 , the organic light emitting diode display 200 includes a display panel 228 including a first substrate 222 and a second substrate 224 , the first substrate 222 and the second substrate 224 . and a first polarizing plate 226 and a second polarizing plate 228 attached to the second substrate 224 . In order to receive and support the first substrate 220 , a back cover 230 , which is a substantially flat structure, is positioned. An adhesive layer 260 is interposed between the upper surface of the peripheral portion of the back cover 230 and the lower surface of the peripheral portion of the first substrate 222 of the display panel 220 . Although not shown in the drawings, the organic light emitting diode display 200 includes a cabinet (not shown) for guiding the edge of the display panel 220 and the second substrate 224 to protect the display panel 220 . It may include a cover window (not shown) positioned.

The back cover 230 may have a plate shape covering the rear surface of the display panel 220 . In an exemplary embodiment, the back cover 230 may be made of aluminum, stainless steel, glass, or the like. Optionally, the back cover 230 may have a triple structure of upper and lower first and second metal layers, and an inorganic layer between these metal layers. This metal layer serves to radiate high-temperature heat generated in the display panel 220 .

As in the first embodiment, the adhesive layer 260 of the present invention distributes stress due to an external force applied from the outside due to its soft property, and applies an external impact to the display panel 220 constituting the organic light emitting diode display 200 . do not pass on In addition, since the ends of the linear molecules introduced into the binder resin have strong cohesive force due to chain extension, not only good impact resistance but also strong adhesion. As such, by ensuring good impact resistance against external force and strong adhesive force, it is possible to prevent the display panel 220 from being deformed due to an external impact, thereby preventing defects such as light leakage.

The display panel 220 constituting the organic light emitting diode display 200 according to the second embodiment of the present invention will be described in more detail with reference to FIG. 10 . As shown in FIG. 10 , the display panel 220 constituting the organic light emitting diode display according to the second embodiment of the present invention includes a display area DR and a non-display area NDR around the display area DR. This is defined, and the first substrate 222 and the second substrate 224 are spaced apart from each other and face each other. The first substrate 222 and/or the second substrate 224 constituting the display panel 220 may be formed of glass or flexible plastic. For example, the first substrate 222 and the second substrate 224 may be formed of polyimide, polyethersulfone, polyetherimide (PEI) and/or polyethylene terephthalate (PET). material can be manufactured. By adopting such a plastic material, it can be applied as a flexible substrate.

A switching thin film transistor (not shown), a driving thin film transistor (DTr), and an organic light emitting diode (E) in each pixel region constituting the display region DR of the first substrate 222, which may be a glass or plastic substrate The organic light emitting device 270 including the is positioned. At this time, in order to encapsulate the first substrate 222 and the organic light emitting device 270 , the second substrate 224 is formed to face the first substrate 222 through an adhesive or a filling sealing material 292 . are cemented

An organic light emitting device 270 including a plurality of electrodes, signal wires, and layers is formed on the first substrate 222 , which will be described in detail. A semiconductor layer 274 is formed in each pixel area of the display area DR of the first substrate 222 . The semiconductor layer 274 includes an active region 274a made of silicon and forming a channel in the central portion, and source and drain regions 274b and 274c doped with high concentrations of impurities on both sides of the active region 274a.

A gate insulating layer 273 made of an inorganic material such as silicon oxide or silicon nitride is formed on the semiconductor layer 274 . In each pixel region in the display region DR, a gate electrode 271 is formed above the gate insulating layer 273 to correspond to the active region 274a of the semiconductor layer 274, and a gate line (not shown) extending in one direction. is formed.

In particular, a first passivation layer 278a is formed on the entire upper surface of the gate electrode 271 and the gate wiring (not shown). The first passivation layer 264 may be made of an inorganic material such as silicon oxide or silicon nitride, or an organic material such as photoacrylic. The first passivation layer 278a and the gate insulating layer 273 thereunder are formed to expose the source and drain regions 274b and 274c located on both sides of the active region 274a constituting the center of the semiconductor layer 274 , respectively. 1 and 2 semiconductor layer contact holes 275a and 275b are provided.

Although not shown in the drawings, on the first passivation layer 278a including the semiconductor layer contact holes 275a and 275b, a data line (not shown) that crosses a gate line (not shown), defines a pixel area, and is made of a metal material. ) and spaced apart from each other, power wiring (not shown) is formed. Optionally, the power wiring (not shown) may be formed on the gate insulating layer 273 on which the gate wiring (not shown) is formed to be spaced apart from and parallel to the gate wiring (not shown).

In addition, in the display region DR, the first and second semiconductor layer contact holes 275a and 275b are spaced apart from each other on the first passivation layer 278a including the first and second semiconductor layer contact holes 275a and 275b. Source and drain electrodes 276 and 277 respectively contacting the exposed source and drain regions 274b and 274c are formed.

A semiconductor layer 274 including source and drain electrodes 276 and 277, source and drain regions 274b and 274c in contact with the electrodes 276 and 277, and a gate insulating film formed over the semiconductor layer 274 273 and the gate electrode 271 constitute the driving thin film transistor DTr. Although not shown in the drawings, a data line defining a pixel area is formed by crossing a gate line (not shown). In addition, the switching thin film transistor (not shown) has the same structure as the driving thin film transistor DTr and is connected to the driving thin film transistor DTr.

In the drawings, as the configuration of the driving thin film transistor (DTr) and the switching thin film transistor (not shown), a top gate type in which the semiconductor layer 274 is made of polysilicon is shown as an example, but the semiconductor layer is pure and impurity amorphous. It may be formed as a bottom gate type made of silicon.

Meanwhile, a second passivation layer 278b is formed on the entire surface of the first substrate 222 including the driving thin film transistor DTr and the switching thin film transistor (not shown) in the display area DR. A drain contact hole 279 is formed in the second passivation layer 278b, and through the drain contact hole 279, the first electrode 282 constituting the organic light emitting diode E is connected to the drain of the driving thin film transistor DTr. It may be in electrical contact with the electrode 277 . The second passivation layer 278b may be made of an inorganic material such as silicon oxide or silicon nitride, but may be formed of, for example, an organic insulating material such as photoacrylic to have a flat surface.

On the other hand, the first electrode 282 , the organic light emitting layer 284 , and the second electrode 286 constituting the organic light emitting diode E are sequentially formed in the region for displaying an image substantially above the second passivation layer 278b . is formed The first electrode 282 is connected to the drain electrode 277 of the driving thin film transistor DTr.

Exemplarily, as the first electrode 282 , as an anode electrode, indium-tin-oxide (ITO), which is a material having a relatively high work function value, may be used. Meanwhile, the second electrode 286 may be a cathode electrode, and is made of aluminum (Al) or an aluminum alloy (AlNd), which is a material having a relatively low work function value.

The organic light emitting layer 284 stacked between the first electrode 282 and the second electrode 286 may be formed of a single layer made of a light emitting material. In an alternative embodiment, the organic light emitting layer 284 is formed of a hole injection layer (HIL), a hole transporting layer (HTL), an emitting material layer (EML), an electron transporting layer (ETL). ) and a multilayer of an electron injection layer (EIL) to maximize luminous efficiency.

Accordingly, when a predetermined voltage is applied to the first electrode 282 and the second electrode 286 according to the color signal selected from the organic light emitting device 270, the holes injected from the first electrode 282 and the second electrode ( Electrons applied from 286) are transported to the organic light emitting layer 284 to form excitons, and when these excitons are transitioned from an excited state to a ground state, light is generated and emitted in the form of visible light. In this case, in the case of the bottom emission type, the emitted light passes through the transparent first electrode 282 and exits to the outside, so that the organic light emitting device 270 implements an arbitrary image.

Meanwhile, the first electrode 282 is formed for each pixel area, and a bank 283 is positioned between the first electrodes 282 formed for each pixel area. The bank 283 may be in the form of an organic insulating layer. For example, the bank 283 surrounds each pixel and overlaps the edge of the first electrode 282 , and may form a grid having a plurality of openings throughout the display area DR. That is, the bank 283 is formed in a matrix type of a lattice structure as a whole of the first substrate 201, and the first electrode 282 is separated for each pixel area by using the bank 283 as a boundary for each pixel area. is formed

Optionally, a passivation layer 290 may be formed on the entire surface of the organic light emitting device 270 . Since the second electrode 286 alone cannot completely suppress the penetration of moisture into the organic light emitting layer 284, by forming the passivation layer 280 on the entire surface of the organic light emitting diode 270, the organic light emitting diode E, especially It is possible to suppress penetration of moisture into the organic light emitting layer 284 .

In one exemplary embodiment, the passivation layer 290 may have a single-layer structure composed of an inorganic insulating material such as silicon oxide or silicon nitride. In another exemplary embodiment, the passivation layer 290 includes a first inorganic layer (not shown) laminated on the second electrode 286 using an inorganic insulating material such as silicon oxide or silicon nitride, and an olefin-based resin. , an organic layer (not shown) laminated on top of the first inorganic layer (not shown) using a polymer material such as epoxy resin, fluororesin, polyethylene terephthalate (PET), and polysiloxane, such as silicon oxide or silicon nitride It may have a multi-layered structure such as a second inorganic layer (not shown) stacked on top of an organic layer (not shown) using an inorganic insulating material.

Hereinafter, the present invention will be described in more detail through exemplary examples, but the present invention is not limited to the technical ideas described in the following examples.

Example : Manufacture of adhesive in which mobile compound is introduced into binder resin

As the main chain of the binder resin, 30 parts by weight of each of acrylic acid and methacrylic acid were used, hexamethylenediamine in a molar ratio of 0.5 to 2.0 relative to acrylic acid, and 3 parts by weight of Irgacure 184 as a photopolymerization initiator were added, followed by an LED lamp (wavelength 365 nm). ), to obtain a binder resin in which polyhexamethylenediamine was introduced through an amide bond in the carboxyl group constituting the acrylic acid-methacrylic acid copolymer. Polyhexamethylenediamine-introduced binder resin was added with alpha-cyclodextrin having an acrylate compound at the terminal as a polyethylene glycol base, along with 2 parts by weight of Irgacure 184, and the linear molecule hexamethylenediamine was converted to alpha-cyclodextrin. While induced to penetrate, crosslinks formed between adjacent alpha-cyclodextrins.

Cyanurate reacted with an amine group formed at the end of the linear molecule into which the crosslinked cyclodextrin was introduced was added in the same molar ratio to the amine group, thereby introducing cyanurate linked by a urea bond to the end of the linear molecule. By adding polyhexamethylenediol in an excess of 5 to 20 molar ratio compared to the remaining isocyanate group as a chain extender to remove the activity of the reactive isocyanate at the terminal and secure flexibility, the urethane bond is formed according to the reaction of the reactive isocyanate at the terminal with the polyol. The formed breaker was formed. In this way, an adhesive in which a linear molecule, a mobile cyclic molecule, and a blocking group were introduced into the binder resin was prepared.

comparative example One: hot melt -type adhesive

Henkel 3581 adhesive was purchased as a hot-melt-type adhesive and used in the experimental examples to be described later.

comparative example 2: acrylate Adhesive composed of binder resin

In order to synthesize the acrylate-based binder resin, 20 parts by weight of methyl methacrylate, which is an acrylate-based compound, 20 parts by weight of acrylic acid octyl ester, 15 parts by weight of isobornyl acrylate, 15 parts by weight of isobornyl methacrylate, 1-[ 30 parts by weight of 2-(isobutyloxy)-1-methylethyl]-2,2-dimethylpropyl-2-methylpropane, 3 parts by weight of Irgacure as a photoinitiator, 1,2-cyclohexanedicarboxylic acid and disulfide as a plasticizer An adhesive composed of an acrylate-based binder resin was prepared by irradiating UV (wavelength 365 nm) from an LED lamp to a liquid adhesive containing 10 parts by weight of each sobornyl ester.

comparative example 3: Urethane acrylate Adhesive composed of binder resin

In order to synthesize the urethane acrylate resin, 9 parts by weight of N-Acryloyl morpholine, which is an acrylate-based compound, 8 parts by weight of isobornyl acrylate, 20 parts by weight of 2-phenoxyethyl acrylate, 20 parts by weight of tetraethylene glycol diacrylate and 10 parts by weight of tetraethylene glycol were added. 19 parts by weight of polyether polyol and 14 parts by weight of diphenylmethane diisocyanate (MDI) were added to synthesize the urethane prepolymer. As a photoinitiator for curing the acrylate-based compound, UV (wavelength 365 nm) is irradiated from an LED lamp to a liquid adhesive with 3 parts by weight of Irgacure 184 added, and the urethane prepolymer is moisture-cured to obtain an adhesive composed of a urethane acrylate-based binder resin. prepared.

Experimental example : Physical property evaluation

For the adhesives prepared in Examples and Comparative Examples 1 to 3, respectively, a load at specific elongation (LASE) was measured. The adhesive prepared in Examples and Comparative Examples was placed on a release film, and a Dogbone (75 mm x 30 mm x 2 mm) sample was prepared. LED 405 nm spot cure was used to cure these liquid adhesives. In order to measure the stress according to the tensile rate for a dogbone specimen with a thickness of 2 mm, the tensile rate was set to 5 mm/min, aged for more than 1 day, and the load at specific elongation (Load at specific elongation, LASE) was measured.

At the same time, the toughness of these adhesives was measured. After applying and curing each adhesive to the backlight unit made of PC material, a tip over the thickness of each sample was press-fitted using a micro-indenter device to measure the toughness to the depth at which the sample fracture occurred. When calculating the toughness, it was calculated by converting it from the Force-Depth graph to the Stress-Strain Curve. Strain=length deformation/sample length, Stress=force/area, where the area is the area of the indenter tip, which was calculated assuming ^{1mm 2 .}

The measurement results according to this experimental example are shown in FIG. 10 and Table 1 below. The adhesive according to the embodiment of the present invention has a low modulus value (G') and a high toughness value (ε), so that flexibility is improved to relieve stress, and has good adhesion. On the other hand, the hot melt type adhesive used in Comparative Example 1 had both high modulus and toughness values, and thus had poor flexibility. In addition, it was determined that the acrylate-type adhesive prepared in Comparative Example 2 had a high modulus value, but a low toughness value, so that both shock absorption and adhesive strength were lowered. The urethane acrylate type adhesive prepared in Comparative Example 3 had both low modulus and toughness values, so it was determined that the adhesive strength was relatively low.

Evaluation of adhesive properties 25% LASE [kgf/㎠] Tensile rate (%) toughness Example (Introduction of Molecular Molecules) 0.64 753 3031 Comparative Example 1 (Hot-melt) 54.6 873 yield point Comparative Example 2 (Acrylic) 3.19 120 975 Comparative Example 3 (urethane acrylic) 0.64 250 1175

In the above, the present invention has been described based on exemplary embodiments and examples of the present invention, but the present invention is not limited to the technical ideas described in the above-described embodiments and examples. Rather, those skilled in the art to which the present invention pertains will be able to propose various modifications and changes based on the above-described embodiments and examples. However, it will become clearer through the appended claims that all such changes and modifications fall within the scope of the present invention.

100, 200: display device 120, 220: display panel
122, 222: first substrate 124, 224: second substrate
126, 226: first polarizing plate 128, 228: second polarizing plate
130: backlight unit 134: light guide plate
140: main frame 150: bottom frame
160, 260: adhesive layer 230: back cover
Tr: thin film transistor TrA: switching area
P: Pixel area DR: Display area
NDR: non-display area DTr: driving thin film transistor
E: organic light emitting diode

Claims (14)

binder resin; and
It contains a mobile compound introduced into the side chain of the binder resin,
The mobile compound includes a cyclic molecule, a linear molecule introduced into the side chain of the binder resin and penetrating the cyclic molecule, and a blocking group disposed at the end of the linear molecule to prevent separation of the cyclic molecule ), including
The linear molecule includes a first linear molecule including a polyaminealkylene compound connected to the binder resin, and a second linear molecule connected to the first linear molecule through a urea bond and containing a polyoxyalkylene compound glue.
The method of claim 1,
The cyclic molecule is an adhesive selected from the group consisting of cyclodextrin, cucurbituril and calixarene.
The method of claim 1,
An adhesive in which a compound having an ethylenic double bond is introduced at the terminal of the cyclic molecule.
binder resin; and
It contains a mobile compound introduced into the side chain of the binder resin,
The mobile compound includes a cyclic molecule, a linear molecule introduced into the side chain of the binder resin and penetrating the cyclic molecule, and a blocking group disposed at the end of the linear molecule to prevent separation of the cyclic molecule ), including
wherein the cyclic molecule is crosslinked with an adjacent cyclic molecule.
display panel;
a structure supporting the display panel; and
an adhesive layer positioned between the display panel and the structure;
The adhesive layer includes a binder resin and a mobile compound introduced into a side chain of the binder resin,
The mobile compound includes a cyclic molecule, a linear molecule introduced into the side chain of the binder resin and penetrating the cyclic molecule, and a blocking group disposed at the end of the linear molecule to prevent separation of the cyclic molecule ), including
The linear molecule includes a first linear molecule including a polyaminealkylene compound connected to the binder resin, and a second linear molecule connected to the first linear molecule through a urea bond and containing a polyoxyalkylene compound display device.
6. The method of claim 5,
The cyclic molecule is a display device selected from the group consisting of cyclodextrin, cucurbituril, and calixarene.
6. The method of claim 5,
A display device in which a compound having an ethylenic double bond is introduced at a terminal of the cyclic molecule.
display panel;
a structure supporting the display panel; and
an adhesive layer positioned between the display panel and the structure;
The adhesive layer includes a binder resin and a mobile compound introduced into a side chain of the binder resin,
The mobile compound includes a cyclic molecule, a linear molecule introduced into the side chain of the binder resin and penetrating the cyclic molecule, and a blocking group disposed at the end of the linear molecule to prevent separation of the cyclic molecule ), including
wherein the cyclic molecule is cross-linked with an adjacent cyclic molecule.
9. The method according to any one of claims 5 to 8,
The display panel is a liquid crystal panel, and the structure is a backlight unit.
9. The method according to any one of claims 5 to 8,
The display panel includes an organic light emitting diode, and the structure is a back cover.
applying an adhesive to one surface of a structure supporting a display panel; and
and bonding the display panel to the structure to which the adhesive is applied,
The adhesive includes a binder resin and a mobile compound introduced into a side chain of the binder resin, wherein the mobile compound includes a cyclic molecule, a linear molecule introduced into the side chain of the binder resin and penetrating the cyclic molecule; , comprising a blocking group disposed at the end of the linear molecule to prevent separation of the cyclic molecule,
The linear molecule includes a first linear molecule including a polyaminealkylene compound connected to the binder resin, and a second linear molecule connected to the first linear molecule through a urea bond and containing a polyoxyalkylene compound A method of manufacturing a display device.
binder resin; and
It contains a mobile compound introduced into the side chain of the binder resin,
The mobile compound includes a cyclic molecule, a linear molecule grafted to the side chain of the binder resin, penetrating the cyclic molecule, and a blocking group disposed at the end of the linear molecule to prevent separation of the cyclic molecule glue that does.
13. The method of claim 12,
wherein the cyclic molecule is crosslinked with an adjacent cyclic molecule.
display panel;
a structure supporting the display panel; and
an adhesive layer positioned between the display panel and the structure;
The adhesive layer is a display device comprising the adhesive according to claim 12 or 13.

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