KR20170010289A - Liquid crystal display device and method of manufacturing the same - Google Patents
Liquid crystal display device and method of manufacturing the same Download PDFInfo
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- KR20170010289A KR20170010289A KR1020150102077A KR20150102077A KR20170010289A KR 20170010289 A KR20170010289 A KR 20170010289A KR 1020150102077 A KR1020150102077 A KR 1020150102077A KR 20150102077 A KR20150102077 A KR 20150102077A KR 20170010289 A KR20170010289 A KR 20170010289A
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- adhesive member
- cover glass
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/13338—Input devices, e.g. touch panels
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- Nonlinear Science (AREA)
- Chemical & Material Sciences (AREA)
- Mathematical Physics (AREA)
- Crystallography & Structural Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Organic Chemistry (AREA)
- Liquid Crystal (AREA)
- Adhesives Or Adhesive Processes (AREA)
Abstract
A liquid crystal display device and a method of manufacturing the same are provided. The liquid crystal display includes a substrate assembly, a cover glass, and an adhesive member. The substrate assembly includes a lower substrate and an upper substrate facing each other, and a lower substrate protrudes from one surface of the upper substrate in the pad region. The cover glass is opposed to the substrate assembly. The bonding member adheres the cover glass to the lower substrate on the lower substrate of the substrate assembly protruding from the pad region, so that the deformation of the lower substrate is minimized even if the distance between the cover glass and the lower substrate changes.
Description
The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device with minimized light leakage and improved durability and a method of manufacturing the same.
BACKGROUND ART A liquid crystal display (LCD) is a display device that implements an image in such a manner that a light source is disposed under a liquid crystal and an electric field is applied to the liquid crystal to control the arrangement of liquid crystal to pass or block light generated in the light source . Since a liquid crystal display device has a thinner thickness and a clearer image quality than a cathode ray tube (CRT) display device, the liquid crystal display device is applied to a TV, a monitor, and the like, and is recently widely used as a display device of a portable terminal such as a smart phone or a tablet PC have.
Since the liquid crystal display implements an image by controlling the arrangement of the liquid crystals, it is necessary to keep the initial arrangement of the liquid crystals constant. If the arrangement of the initial liquid crystals is locally turned off, the arrangement of the liquid crystals can not be controlled as desired, resulting in unevenness on the screen or leakage of light between the misaligned liquid crystals. Accordingly, researches for analyzing the causes of light leakage in a liquid crystal display device and reducing light leakage are actively underway. In addition, since the liquid crystal display device is applied to a portable terminal such as a smart phone, a tablet PC and the like, the durability of the liquid crystal display device becomes important, and studies for improving the durability of the liquid crystal display device are actively underway.
There are various factors that cause light leakage in the liquid crystal display device and factors that reduce the durability. However, the lower substrate of the liquid crystal display device may be bent to generate light leakage, and the lower substrate of the liquid crystal display device may be easily damaged by the impact. Thus, the durability of the liquid crystal display device can be reduced. Particularly, light leakage frequently occurs at the edge of the display area adjacent to the pad area of the liquid crystal display device, and breakage of the lower substrate frequently occurs in the pad area of the liquid crystal display device. That is, the pad area of the liquid crystal display device is a region where a flexible printed circuit board (FPCB) contacts the panel of the liquid crystal display device, and the thin lower substrate of the liquid crystal display device is exposed alone. The thin lower substrate and the cover glass of the liquid crystal display device are bonded with an adhesive member. However, in general, since the bonding member is a rigid member having a large elastic modulus, it may cause bending of the lower substrate in the manufacturing process of the liquid crystal display device, and may cause light leakage. Further, the rigidity of the adhesive member is insufficient to buffer external impacts, so that the durability of the liquid crystal display device can be reduced.
The inventors of the present invention have recognized that the lower substrate of the pad region may be bent due to the rigidity of the adhesive member, thereby causing light leakage and reducing the durability of the liquid crystal display device. Reference is now made to Figs. 1A and 1B to describe this in more detail.
FIG. 1A is a schematic perspective view illustrating a light leakage phenomenon and a durability reduction phenomenon occurring in a liquid crystal display device. FIG. 1B is a schematic cross-sectional view taken along line I-I 'of FIG. 1A for explaining a light leakage phenomenon and a durability reduction phenomenon generated in a liquid crystal display device.
1A and 1B, a
The display printed
An
1B, the
Thereafter, with the
In this case, in order to maintain the alignment of the
When the electrostatic chuck pressing the
The bending of the
On the other hand, since the
As described above, the
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of bonding a cover glass and a substrate assembly by applying an adhesive member that minimizes deformation of a lower substrate even when a distance between a cover glass and a lower substrate is changed, The present invention provides a liquid crystal display device and a method of manufacturing the same that minimize the bending of a lower substrate that may be generated in the process and minimize light leakage.
Another object of the present invention is to provide a composition for an optical bonding member having an elastic modulus and elongation suitable for maintaining alignment of a cover glass and a substrate assembly in a process of removing air bubbles between a cover glass and a composition for an optical adhesive member, There is provided a liquid crystal display device having improved productivity and durability by using an adhesive member having an elastic modulus and elongation suitable for minimizing deformation of a lower substrate and absorbing an impact applied to a lower substrate after cured .
The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.
According to an aspect of the present invention, there is provided a liquid crystal display device including a substrate assembly, a cover glass, and an adhesive member. The substrate assembly includes a lower substrate and an upper substrate facing each other, and a lower substrate protrudes from one surface of the upper substrate in the pad region. The cover glass is opposed to the substrate assembly. The bonding member adheres the cover glass to the lower substrate on the lower substrate of the substrate assembly protruding from the pad region, so that the deformation of the lower substrate is minimized even if the distance between the cover glass and the lower substrate changes.
According to another aspect of the present invention, the thickness of the adhesive member changes to a thickness corresponding to the distance between the cover glass and the lower substrate when the distance between the cover glass and the lower substrate changes.
According to another aspect of the present invention, an adhesive member is formed of an additive which is mixed with an ultraviolet-curable composition and an ultraviolet-curable composition and reduces the elastic modulus of the adhesive member by heat or infrared rays, and increases the elongation of the adhesive member.
According to still another aspect of the present invention, there is provided an ultraviolet curable composition comprising a monofunctional acrylate monomer, a polyfunctional epoxy acrylate oligomer having at least two functional groups, a photoinitiator, and a silane compound And the additive is an ethoxyacrylate compound represented by the following general formula (1).
[Chemical Formula 1]
(Provided that R1 and R2 are each independently a hydrogen atom or a C1 to C5 alkyl group, and n is an integer of 5 to 40)
According to another feature of the present invention, the additive is included in an amount of 10 wt% to 30 wt% based on the total weight of the ultraviolet curable composition and the additive.
According to another aspect of the present invention, the adhesive member has a first modulus of elasticity and a first elongation at curing of the ultraviolet-curable composition, wherein the additive reacts with heat or infrared rays to change the modulus of elasticity of the adhesive member to less than the
According to another aspect of the present invention, the first elastic modulus is greater than or equal to 480 N / mm 2 at room temperature (25 ° C), the second elastic modulus is from 100 N / mm 2 to 170 N / mm 2 at room temperature , The first elongation is less than or equal to 90%, and the second elongation is greater than or equal to 300%.
According to another aspect of the present invention, the pad region of the lower substrate includes a driving chip region in which the driving chip is disposed and a touch pad region in which the touch pads are disposed on both sides of the driving chip region, Respectively.
According to another aspect of the present invention, the liquid crystal display further includes an optical bonding member disposed between the cover glass and the upper substrate, and a dam member surrounding the optical bonding member.
According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device including forming a dam member on an upper substrate of a substrate assembly including a lower substrate and an upper substrate facing each other, Applying a composition for an optical adhesive member on a substrate, applying a composition for an adhesive member onto a lower substrate projecting from a pad surface at one side of the upper substrate, forming a composition for an adhesive member on a lower surface of the cover glass facing the substrate assembly Pressing the cover glass using an electrostatic chuck so as to be in contact with the cover member; curing the composition for the adhesive member so that the adhesive member is formed; Separating the glass from the glass and raising the process pressure, Curing the composition for the optical bonding member such that the cover glass and the upper substrate of the substrate assembly are adhered to each other, reducing the elastic modulus of the adhesive member, and heating the adhesive member to increase the elongation of the adhesive member Or irradiating the adhesive member with infrared light.
According to another aspect of the present invention, the step of pressurizing the cover glass using the electrostatic chuck such that the composition for the adhesive member is brought into contact with the bottom surface of the cover glass opposite to the substrate assembly is performed by moving the distance between the cover glass and the lower substrate to the first distance Wherein the step of curing the composition for the adhesive member to form the adhesive member comprises curing the composition for the adhesive member such that the adhesive member has a first thickness corresponding to the first distance.
According to still another aspect of the present invention, the step of separating the electrostatic chuck from the cover glass and raising the process pressure so that the composition for the optical bonding member covers the entire surface of the upper substrate inside the dam member is performed between the cover glass and the lower substrate Of the adhesive member to a second distance larger than the first distance by applying heat to the adhesive member to reduce the elastic modulus of the adhesive member and to increase the elongation of the adhesive member, The step of increasing the thickness of the adhesive member from a first thickness to a second thickness corresponding to a second distance.
According to another aspect of the present invention, there is provided a method of manufacturing an optical element, comprising the steps of: curing a composition for an optical bonding member such that a cover glass and an upper substrate of a substrate assembly are adhered to each other; The step of applying heat or irradiating infrared rays to the adhesive member is performed simultaneously.
The details of other embodiments are included in the detailed description and drawings.
The present invention minimizes the light leakage caused by the deformation of the lower substrate by using the adhesive member which minimizes the deformation of the lower substrate even if the distance between the cover glass and the lower substrate is changed by bonding the cover glass and the lower substrate have.
INDUSTRIAL APPLICABILITY The present invention can improve the productivity of a liquid crystal display device by using an adhesive member having a large elastic modulus and a small elongation ratio by a first reaction and having a small elastic modulus and a large elongation by a secondary reaction, There is an effect of improving the durability.
The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the specification.
FIG. 1A is a schematic perspective view illustrating a light leakage phenomenon and a durability reduction phenomenon occurring in a liquid crystal display device. FIG.
1B is a schematic cross-sectional view taken along line I-I 'of FIG. 1A for explaining a light leakage phenomenon and a durability reduction phenomenon generated in a liquid crystal display device.
2A is a schematic plan view illustrating a liquid crystal display according to an embodiment of the present invention.
FIG. 2B is a schematic cross-sectional view taken along line II-II 'of FIG. 2A for explaining a liquid crystal display device according to an embodiment of the present invention.
3 is a graph for explaining change in elastic modulus of a bonding member included in a liquid crystal display device according to an embodiment of the present invention.
4A to 4F are schematic cross-sectional views illustrating a process of minimizing deformation of a lower substrate included in a liquid crystal display device according to an exemplary embodiment of the present invention.
5A to 5C are schematic plan views and graphs for explaining reduced light leakage phenomenon of a liquid crystal display device according to an embodiment of the present invention.
6 is a schematic flowchart for explaining a method of manufacturing a liquid crystal display device according to an embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.
The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Where the terms "comprises", "having", "done", and the like are used in this specification, other portions may be added unless "only" is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.
In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.
In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.
It is to be understood that an element or layer is referred to as being another element or layer " on ", including both intervening layers or other elements directly on or in between.
Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.
Like reference numerals refer to like elements throughout the specification.
The sizes and thicknesses of the individual components shown in the figures are shown for convenience of explanation and the present invention is not necessarily limited to the size and thickness of the components shown.
It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.
Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
2A is a schematic plan view illustrating a liquid crystal display according to an embodiment of the present invention. FIG. 2B is a schematic cross-sectional view taken along line II-II 'of FIG. 2A for explaining a liquid crystal display device according to an embodiment of the present invention. 2A and 2B, a
The
The
The driver chip DI, the touch pad TP and the
The driving chip DI is connected to the display printed
The touch pad unit TP is connected to the touch printed
The
Referring to FIG. 2B, in the non-pad region NPA, the
The
The
The
The
The
As shown in FIG. 2B, the
Further, the
The
The UV curable composition comprises a monofunctional acrylate monomer, a multifunctional acrylate oligomer having at least two functional groups, a photoinitiator and a silane based compound.
Monofunctional acrylate monomers include monomers containing one acrylate functional group such as 2-hydroxyethyl acrylate (2-HEA), 2-carboxyethyl acrylate (2- carboxyethyl acrylate (2-CEA), tertiary butyl cyclohexanol acrylate, C16 / C18 alkyl acrylate, C12 alkyl acrylate (Lauryl acrylate), C12 / C14 acrylate, 2-phenoxyethyl acrylate (2-PEA), ethoxylated 4 phenyl acrylate (P4EOA), isooctyl acrylate Octyl acrylate (IOA), octyl decyl acrylate (ODA), etc. However, the monofunctional acrylate monomer is not limited thereto, and one acrylate functional group There are a variety of acrylate monomers containing may be used. Monofunctional acrylate-based monomer may be included as a 5 wt% to 30 wt%, based on the total weight of the composition of the binding material.
The polyfunctional acrylate oligomer is an acrylate oligomer having at least two acrylate functional groups. For example, an epoxy acrylate oligomer containing two to six acrylate functional groups may be used. However, the polyfunctional acrylate oligomer is not limited thereto, and various acrylate oligomers including at least two acrylate functional groups may be used. The polyfunctional acrylate oligomer is polymerized with a monofunctional acrylate monomer to form an acrylate polymer having a network structure, through which an
The photoinitiator initiates polymerization of monofunctional acrylate monomer and polyfunctional acrylate oligomer in response to ultraviolet radiation. Photoinitiators include, for example, azo compounds, quinones, nitroso compounds, acyl halides, hydrazones, mercapto compounds, pyrylium compounds, Compounds such as imidazole, cyanuric chloride, benzoin, benzoin arcyl ether, diketone, phenon, benzoin ether, And mixtures thereof. The photoinitiator may be included in an amount of 1 wt% to 10 wt% based on the total weight of the composition for the adhesive member.
The silane-based compound increases the surface adhesion of the
The additive is a compound that decreases the elastic modulus of the
[Chemical Formula 1]
R 1 and R 2 are each independently a hydrogen (H) atom or a C 1 to C 5 alkyl group, and n is an integer of 5 to 40. The ethoxy acrylate-based compound reacts with heat or infrared rays to soften the
(Meth) acrylate (MPEGMA), polyethoxy (5) (meth) acrylate (meth) acrylate (meth) acrylate polyethoxy (5) (meth) acrylate, polyethoxy (10) (meth) acrylate, polyethoxy (30) (meth) (meth) acrylate, behenylpolyethoxy (25) (meth) acrylate, lauryl polyethoxy (23) (meth) acrylate (Laurypolyethoxy (meth) acrylate, methoxypolyethoxy (meth) acrylate, methoxypolyethoxy (meth) acrylate, methoxypolyethoxy (meth) acrylate, (meth) acrylate, methoxypolyethoxy (16) (meth) acrylate and the like can be used. However, the type of the ethoxyacrylate compound is not limited thereto, and various ethoxyacrylate compounds satisfying the above formula (1) can be used. The additive may be included in an amount of 10 wt% to 30 wt% based on the total weight of the composition for the adhesive member.
As mentioned above, the
3 is a graph for explaining change in elastic modulus of a bonding member included in a liquid crystal display device according to an embodiment of the present invention. 3, the elastic modulus of the adhesive member increases to a first elastic modulus (M 1 ) based on the first reaction of the composition for the adhesive member, and the elastic modulus of the first elastic modulus (M 1 ) to the second elastic modulus (M 2 ).
For example, when the composition for the adhesive member is irradiated with ultraviolet rays for T 1 hour, the ultraviolet curable composition contained in the composition for the adhesive member is cured to have the first elastic modulus (M 1 ). Therefore, the adhesive member has a first modulus of elasticity in the first reaction. Here, the elastic modulus means a modulus of elasticity at room temperature (25 ° C), and the first modulus is 480 N / mm 2 . The upper limit value of the first elastic modulus is not particularly limited. That is, the adhesive member may have an arbitrary elastic modulus greater than 480 N / mm < 2 & gt ;, and the higher the elastic modulus of the adhesive member is, the better the rigidity of the adhesive member is, and the adhesive member is aligned with the cover glass- Can be prevented. A detailed description thereof will be given later with reference to Figs. 4A to 4F.
Thereafter, the composition for the adhesive member may be heated or irradiated with infrared rays for T 2 hours at T 1 . In this case, the additive contained in the composition for the adhesive member reduces the elastic modulus of the cured UV-curable composition from the first elastic modulus (M 1 ) to the second elastic modulus (M 2 ). Accordingly, the adhesive member has a second elastic modulus (M 2 ) smaller than the first elastic modulus (M 1 ) in the second-order reaction. Here, the second elastic modulus (M 2 ) has a value selected from 100 N / mm 2 to 170 N / mm 2 .
The adhesive member having the second elastic modulus M 2 is suitable for buffering the impact applied to the lower substrate and is capable of continuously adhering between the cover glass and the lower substrate even if the distance between the cover glass and the lower substrate is changed, And may be suitable for minimizing deformation of the lower substrate. If the elastic modulus of the adhesive member is less than 100 N / mm < 2 >, the adhesive member has too small an elastic force, so that the lower substrate may not be restored when the lower substrate is excessively deformed, It may not be suitable for shock damping. Further, when the elastic modulus of the adhesive member is larger than 170 N / mm < 2 & gt ;, the adhesive member has a too large elastic force. Thus, the bonding member may not be able to adapt to a change in distance between the lower substrate and the cover glass, which may occur in the process of bonding the cover glass and the substrate assembly, and may not minimize deformation of the lower substrate. A detailed description thereof will be given later with reference to Figs. 4A to 4F.
On the other hand, as the modulus of elasticity of the adhesive member is changed based on the primary reaction and the secondary reaction, the elongation percentage of the adhesive member can also be changed. Elongation means the ratio of elongation length of an object when the tensile force is applied to a specific object, and elongation can be increased when the elastic modulus is decreased. As mentioned above, the ultraviolet ray curable composition contained in the composition for the adhesive member is hardened in response to ultraviolet rays. Thus, the elongation percentage of the adhesive member can be reduced during a period of T 1 during which ultraviolet light is irradiated. However, the additives included in the composition for the adhesive member relax the rigidity of the cured UV-curable composition in response to heat or infrared rays. Thus, the elongation percentage of the adhesive member can be increased for T 2 hours at T 1 where heat is applied to the adhesive member or infrared light is irradiated.
For example, the elongation of the adhesive member can be increased at a first elongation rate for a T 1 hour. Here, the first elongation may be less than or equal to 90%. For example, the first elongation may have any value selected from 0% to 90%. When the elongation is 0%, it means that there is no change in the size of the adhesive member when a tensile force is applied to the adhesive member. When the adhesive member has an elongation of less than or equal to 90%, the adhesive member can maintain a constant distance between the cover glass and the lower substrate, and the cover glass and the lower substrate may not be mutually staggered.
Further, the elongation of the adhesive member can be increased at the second elongation rate for T 2 hours at T 1 . For example, the second elongation may be greater than or equal to 300%. If the elongation percentage of the adhesive member is less than 300%, the adhesive member may not adapt to the change in distance between the cover glass and the lower substrate, which may occur in the process of bonding the cover glass and the substrate assembly, When the distance between the upper substrate and the lower substrate is changed, it may fall from the cover glass or the lower substrate. On the other hand, the upper limit value of the second elongation is not particularly limited. That is, since the adhesive member after the secondary reaction must adhere firmly to the cover glass and the lower substrate even if the distance between the cover glass and the lower substrate changes, the higher the elongation of the adhesive member, the better. A detailed description thereof will be given later with reference to Figs. 4A to 4F.
As a result, the elastic modulus of the adhesive member is increased by the first-order reaction and the elongation is reduced. Thus, the adhesive member can be a rigid member. However, the elastic modulus of the adhesive member is decreased by the secondary reaction and the elongation is increased. Therefore, the adhesive member can be a flexible member. Due to the above-described characteristics of the adhesive member, the deformation of the lower substrate, which may occur in the process of the liquid crystal display, can be minimized, and the light leakage phenomenon that can be caused by deformation of the lower substrate can be minimized. In addition, after the liquid crystal display device is manufactured, the adhesive member can prevent damage to the lower substrate by buffering impact applied to the lower substrate.
4A to 4F are schematic cross-sectional views illustrating a process of minimizing deformation of a lower substrate included in a liquid crystal display device according to an exemplary embodiment of the present invention. 4A to 4F, the light leakage phenomenon of the liquid crystal display device may be caused by the deformation of the
Referring first to FIG. 4A, a
Thereafter, the
A
Referring to FIG. 4B, a
Referring to FIG. 4C, the
Ultraviolet rays (UV) are applied to the composition for the adhesive member in a state in which the
The elastic modulus of the
4D, the electrostatic chuck is separated from the
In this case, the
As a result, in order to remove air bubbles between the
In this case, the
Also, the
On the other hand, since the electrostatic chuck is separated from the
The bending of the
4E, a process of removing air bubbles between the composition for the optical bonding member and the
After the optical
Referring to FIG. 4F, the elastic modulus of the
The elastic modulus of the
Alignment of the
As shown in Fig. 4F, the elastic modulus of the
On the other hand, even if the thickness of the
Further, the
That is, since the
As a result, the liquid crystal display according to an embodiment of the present invention includes the
5A to 5C are a plan view and a graph for explaining reduced light leakage phenomenon of the liquid crystal display device according to an embodiment of the present invention.
Referring to FIG. 5A, the active area AA of the
FIG. 5B is a graph obtained by testing whether a light leakage occurs in a liquid crystal display according to a comparative example, and FIG. 5C is a graph obtained by testing whether light leakage occurs in the liquid crystal display according to an exemplary embodiment of the present invention. The liquid crystal display device according to the comparative example and the liquid crystal display device according to the embodiment of the present invention all include the same components except for the adhesive member. The adhesive member of the liquid crystal display device according to the comparative example and the adhesive member of the liquid crystal display device according to the embodiment of the present invention were all disposed at the top of the 21 section and the 1 section shown in Fig. 5A.
On the other hand, the bonding member of the liquid crystal display device according to the comparative example was manufactured using Henkel's 190024 ultraviolet ray curable composition. The elastic modulus of the adhesive member of the liquid crystal display device according to the comparative example was 490 N / mm 2 at room temperature and the elongation was 85%. The adhesive member of the liquid crystal display device according to an embodiment of the present invention was manufactured using the composition for the adhesive member described with reference to Figs. 2A and 2B. The second elastic modulus of the adhesive member of the liquid crystal display device according to an embodiment of the present invention was 169 N / mm 2 at room temperature, and the second elongation was 300%. The first elastic modulus and the first elongation of the adhesive member are merely necessary for maintaining the alignment of the cover glass and the substrate assembly in the process of bonding the cover glass and the substrate assembly. The first elastic modulus and the first elongation of the adhesive member were not measured since the contact member had the second elastic modulus and the second elongation after the assembly was bonded.
The horizontal axis (i.e., the x axis) of the graph in Figs. 5B and 5C represents the sections of the
Referring to FIG. 5B, in the liquid crystal display according to the comparative example, the pLcr value was measured to be high in the 21 section and the 1 section. That is, it can be seen that light leakage can be generated in the upper left section and the upper right section of the
Referring to FIG. 5C, in the liquid crystal display device according to an embodiment of the present invention, the pLcr value in the 21 section and the 1 section is measured to be small. That is, the light leakage of the liquid crystal display according to an embodiment of the present invention is significantly reduced because the bonding member minimizes the deformation of the lower substrate of the liquid crystal display.
On the other hand, although the graph is not shown, the inventor has conducted a drop evaluation to test the improved durability of the liquid crystal display according to an embodiment of the present invention. Specifically, the present inventors dropped 32 liquid crystal display devices according to the comparative example and 32 liquid crystal display devices according to an embodiment of the present invention at a height of 1 m, where the damage of 5.6% And the ratio of the generated liquid crystal display device was calculated.
As a result of the drop evaluation, damage occurred in the ratio of 4.6% in the liquid crystal display device according to the comparative example, but all 32 liquid crystal display devices were not damaged in the liquid crystal display device according to the embodiment of the present invention. Therefore, it can be seen that the adhesive member of the liquid crystal display device according to an embodiment of the present invention can fully buffer external impacts and minimize damage to the lower substrate.
6 is a schematic flowchart for explaining a method of manufacturing a liquid crystal display device according to an embodiment of the present invention. A method of manufacturing a liquid crystal display device according to an embodiment of the present invention has been described above with reference to FIGS. 4A to 4F, and a duplicate description thereof will be omitted.
Referring to FIG. 6, a method of manufacturing a liquid crystal display device according to an embodiment of the present invention includes forming a dam member on an upper substrate of a substrate assembly including a lower substrate and an upper substrate facing each other (S610). Thereafter, the composition for the optical bonding member is coated on the upper substrate, and the composition for the adhesive member is applied on the lower substrate protruded from the one surface of the upper substrate in the pad region (S620). Thereafter, the cover glass is pressed (S630) using an electrostatic chuck so that the composition for the adhesive member is brought into contact with the lower surface of the cover glass opposed to the substrate blank. In this case, the distance between the cover glass and the lower substrate can be reduced to a first distance. Thereafter, the composition for the adhesive member is cured (S640) so that the adhesive member is formed. In this case, the adhesive member may be cured to have a first thickness corresponding to the first distance. Thereafter, the electrostatic chuck is separated from the cover glass so that the composition for the optical adhesive member covers the entire surface of the upper substrate inside the dam member, and the process pressure is increased (S650). When the electrostatic chuck is detached, the cover glass can be raised by the restoring force of the dam member. Thus, the distance between the cover glass and the lower substrate can be increased to a second distance greater than the first distance. Thereafter, the air bubble between the composition for the optical bonding member and the cover glass is removed (S660), and the composition for the optical bonding member is cured (S670) so that the cover glass and the upper substrate of the substrate assembly are bonded. Thereafter, heat is applied to the adhesive member to reduce the elastic modulus of the adhesive member and increase the elongation of the adhesive member, or irradiation of the adhesive member with infrared rays (S680). In this case, the thickness of the adhesive member may be increased from the first thickness to a second thickness corresponding to the second distance.
As described above, the step of applying heat to the bonding member or irradiating infrared rays to the bonding member can be performed simultaneously with the step of curing the composition for the optical bonding member such that the cover glass and the upper substrate of the substrate assembly are bonded. That is, the adhesive member may be subjected to heat or infrared rays while the composition for the optical adhesive member is cured by heat or infrared rays. Thus, a secondary reaction of the adhesive member can be induced.
A method of manufacturing a liquid crystal display device according to an embodiment of the present invention cures a composition for an adhesive member before the electrostatic chuck is separated from the cover glass. That is, an adhesive member having rigidity is formed by a first-order reaction. Thus, even if the electrostatic chuck is separated from the cover glass, the adhesive member having a large elastic modulus and a small elongation can maintain the alignment of the cover glass and the substrate assembly constant, and the air bubble between the composition for the optical adhesive member and the cover glass can be removed Can be easily carried out. Therefore, the defective product generated in the manufacturing process of the liquid crystal display device can be reduced, and the productivity of the liquid crystal display device can be improved. Further, the method of manufacturing a liquid crystal display device according to an embodiment of the present invention reduces the elastic modulus of the adhesive member after the composition for the adhesive member is cured, or during the curing of the composition for the adhesive member, . That is, a secondary reaction can be performed to deform the rigid bonding member into a flexible bonding member. Thus, despite the rise of the cover glass due to the restoring force of the dam member, the lower substrate can be kept flat and the deformation of the lower substrate can be minimized. Therefore, light leakage due to deformation of the lower substrate can be minimized. On the other hand, since the adhesive member having completed the secondary reaction has a modulus of elasticity suitable for buffering the impact applied to the lower substrate, the impact applied to the lower substrate can be absorbed after the liquid crystal display is completed. Thus, the durability of the liquid crystal display device can be improved.
Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those embodiments and various changes and modifications may be made without departing from the scope of the present invention. . Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.
100, 200: liquid crystal display
110, 210: substrate assembly
111 and 211:
112, 212: upper substrate
113, 213: sealant
121, 221: Optical bonding member
122, 222: a dam member
130, 230: cover glass
140, 240: Display printed circuit board
150, 250: touch printed circuit board
160, 260:
423: Composition for optical adhesive member
461: Composition for adhesive member
LC: liquid crystal
ESC: electrostatic chuck
PA: pad area
NPA: non pad area
TP: pad portion
DI: Driving chip
SP / A: Separation area
O / A: overlap area
I / A: Interior space
Claims (13)
A cover glass facing the substrate assembly; And
Wherein the lower substrate and the cover glass are bonded to each other on the lower substrate of the substrate assembly protruding from the pad region so that deformation of the lower substrate is minimized even if the distance between the cover glass and the lower substrate is changed And the liquid crystal display device.
Wherein the thickness of the adhesive member changes to a thickness corresponding to a distance between the cover glass and the lower substrate when the distance between the cover glass and the lower substrate changes.
Wherein the adhesive member comprises:
An ultraviolet ray curable composition; And
And is formed of an additive which is mixed with the ultraviolet curing composition and reduces the elastic modulus of the adhesive member by heat or infrared rays and increases the elongation of the adhesive member.
The UV-
Monofunctional acrylate-based monomers;
A polyfunctional epoxy acrylate oligomer containing at least two functional groups;
Photoinitiators; And
A silane-based compound that improves the adhesion of the ultraviolet-curable composition,
Wherein the additive is an ethoxyacrylate compound represented by the following formula (1).
[Chemical Formula 1]
(Provided that R1 and R2 are each independently a hydrogen atom or a C1 to C5 alkyl group, and n is an integer of 5 to 40)
Wherein the additive is included in an amount of 10 wt% to 30 wt% based on the total weight of the ultraviolet curable composition and the additive.
Wherein the adhesive member has a first modulus of elasticity and a first elongation at curing of the ultraviolet-curable composition,
The additive decreases the elastic modulus of the adhesive member in response to the heat or the infrared rays to a second elastic modulus smaller than the first elastic modulus and increases the elongation percentage of the adhesive member to a second elongation rate larger than the first elongation rate The liquid crystal display device.
The first elastic modulus is greater than or equal to 480 N / mm 2 at room temperature (25 ° C), the second elastic modulus is from 100 N / mm 2 to 170 N / mm 2 at room temperature,
The first elongation is less than or equal to 90%, and the second elongation is greater than or equal to 300%.
Wherein the pad region of the lower substrate includes a driving chip region in which the driving chip is disposed and a touch pad region in which the touch pad is disposed on both sides of the driving chip region,
Wherein the adhesive member is disposed so as to partially overlap the touch pad area.
An optical adhesive member disposed between the cover glass and the upper substrate; And
And a dam member surrounding the optical bonding member.
Applying a composition for an optical bonding member onto the upper substrate, and applying a composition for an adhesive member onto the lower substrate protruding from one surface of the upper substrate in a pad region;
Pressing the cover glass using an electrostatic chuck so that the composition for the adhesive member is brought into contact with the bottom surface of the cover glass facing the substrate assembly;
Curing the composition for the adhesive member so that the adhesive member is formed;
Separating the electrostatic chuck from the cover glass so that the composition for the optical bonding member covers the entire surface of the upper substrate inside the dam member, and raising the process pressure;
Removing air bubbles between the composition for the optical bonding member and the cover glass;
Curing the composition for the optical bonding member such that the cover glass and the upper substrate of the substrate assembly are bonded; And
And applying heat to the adhesive member or irradiating the adhesive member with infrared light so as to decrease the elastic modulus of the adhesive member and increase the elongation of the adhesive member.
The step of pressing the cover glass using the electrostatic chuck such that the composition for the adhesive member is brought into contact with the bottom surface of the cover glass facing the substrate assembly may include reducing the distance between the cover glass and the lower substrate to a first distance , ≪ / RTI >
Wherein the step of curing the composition for the adhesive member such that the adhesive member is formed comprises curing the composition for the adhesive member such that the adhesive member has a first thickness corresponding to the first distance, Gt;
Separating the electrostatic chuck from the cover glass so that the composition for the optical bonding member covers the entire surface of the upper substrate inside the dam member, and raising the process pressure is performed so that the gap between the cover glass and the lower substrate Increasing the distance to a second distance greater than the first distance,
The step of applying heat to the adhesive member or irradiating infrared rays to the adhesive member so as to decrease the elastic modulus of the adhesive member and increase the elongation of the adhesive member may be performed by changing the thickness of the adhesive member from the first thickness To a second thickness corresponding to the second distance. ≪ Desc / Clms Page number 19 >
Curing the composition for the optical bonding member so that the cover glass and the upper substrate of the substrate assembly are adhered to each other; and heating the adhesive member to reduce the elastic modulus of the adhesive member and increase the elongation of the adhesive member Or the step of irradiating the adhesive member with infrared rays are performed simultaneously.
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KR1020150102077A KR20170010289A (en) | 2015-07-18 | 2015-07-18 | Liquid crystal display device and method of manufacturing the same |
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Cited By (1)
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KR20190077903A (en) * | 2017-12-26 | 2019-07-04 | 엘지디스플레이 주식회사 | Flexible display device and method of manufacturing the same |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2002257891A (en) | 2000-12-25 | 2002-09-11 | Hitachi Telecom Technol Ltd | Test aiding device |
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2015
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Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2002257891A (en) | 2000-12-25 | 2002-09-11 | Hitachi Telecom Technol Ltd | Test aiding device |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20190077903A (en) * | 2017-12-26 | 2019-07-04 | 엘지디스플레이 주식회사 | Flexible display device and method of manufacturing the same |
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