KR101878174B1 - Coating material having low refelection and high hardness and display device using the same - Google Patents

Abstract

The present invention relates to a low reflection hardness coating agent capable of enhancing outdoor visibility and maintaining high hardness with a low reflection characteristic and a display using the same, and the low reflection hardness coating agent of the present invention is a composite of polysiloxane and high strength silica, A high hardness binder having a content ratio of 10 wt% to 20 wt%; A backbone such as a high hardness binder and a backbone having a structure in which an ultraviolet curing agent and a thermosetting agent are bonded to both sides of the backbone and a fluorine-substituted polymer having a low refractive property is included, and the refractive index of the high- % Of a low refractive surfactant; And has a high hardness in a range of 7H to 9H and a low refractive index in a range of 1.2 to 1.5, including solvents having a low temperature baking property in a content ratio of 60wt% to 80wt%.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a low reflection hardness coating agent and a display device using the same. BACKGROUND ART [0002]

TECHNICAL FIELD The present invention relates to a coating agent for use in a cover substrate for a display device, and more particularly, to a low reflection hardness coating agent capable of improving outdoor visibility and maintaining high hardness with a low reflection characteristic and a display device using the same.

Recently, mobile electronic devices widely used include a display device for displaying an image. As a mobile display device, a liquid crystal display (LCD) and an organic light emitting diode (OLED) display device are mainly used. The liquid crystal display device displays an image by using electrical and optical characteristics of liquid crystal having anisotropy such as refractive index and permittivity. By adjusting the light transmittance of each pixel through the polarizing plate in accordance with the data signal, . The organic light emitting diode display device is a self-light emitting device that emits an organic light emitting layer by recombination of electrons and holes, and the driving circuit of each pixel implements the gradation by adjusting the current supplied to the organic light emitting diode according to the data signal.

Mobile devices should have sufficient visibility both indoors and outdoors in their use environment. In recent years, application of window glass and touch screen panel has become common in mobile devices, so that outdoor visibility has become a problem.

As a window glass attached to a cover substrate on a touch screen panel, a tempered glass having high durability is mainly used. Conventionally, a cover substrate is attached on a touch screen panel using SVR (Super Viewing Resin) as an adhesive in order to improve visibility due to external light reflection. However, although SVR can reduce the reflection generated in the interior of the cover substrate, the touch screen panel, or the liquid crystal display device, the SVR can not prevent the diffused external light generated on the surface of the cover substrate, .

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art, and it is an object of the present invention to provide a low reflection hardness coating agent capable of improving outdoor visibility and low hardness, .

In order to solve the above-mentioned problems, the low reflection hardness coating agent according to one embodiment comprises a high hardness binder having a content ratio of 10 wt% to 20 wt% constituting a network of polysiloxane and high strength silica hybrid; Wherein the binder has a backbone such as the high hardness binder and a structure in which an ultraviolet curing agent and a thermosetting agent are bonded to both sides of the backbone and a low refractive index fluorine- A low refractive surfactant in a 20 wt% content ratio; And has a high hardness in a range of 7H to 9H and a low refractive index in a range of 1.2 to 1.5, including solvents having a low temperature baking property in a content ratio of 60wt% to 80wt%.

Low refractive surfactants including PFPE (PerFluoroPolyEthers) represented by formula (1) below, the hardness of the PFPE backbone, such as a binder _{"-CH 2 CF 2 O - [} - (CF 2 CF 2 O) m - (CF 2) O _n -CF ₂ CH ₂ - ".

≪ Formula 1 >

Where n and m are in the range of 1 to 10.

The high hardness binder further comprises a urethane acrylate.

The refractive index of the high hardness binder is in the range of 1.5 to 1.6, which is larger than the refractive index of the low reflection hardness coating.

The solvent includes an alcoholic solvent which is fired at a temperature of 150 DEG C or lower.

A display device according to an embodiment of the present invention includes: a display module in which a touch sensor is integrated; And a cover substrate coated with the low reflection hardness coating agent attached to the display module. The display module includes a display panel, which is one of a liquid crystal panel and an organic light emitting diode display panel, and a touch panel attached by a first adhesive layer on the display panel. The cover substrate is attached by a second adhesive layer on the touch panel.

The low-hardness low-reflection coating agent according to the present invention can contain a fluorine-substituted polymer surfactant having a backbone such as a high-hardness binder to ensure low refractive properties while maintaining high hardness.

Accordingly, the high-hardness low-reflection coating agent according to the present invention is coated on the cover substrate to prevent reflection of external light, thereby improving external visibility and maintaining high hardness.

1 is a graph showing hardness-refractive index characteristics of a low reflection hardness coating agent according to an embodiment of the present invention.
2A and 2B are graphs showing the results of measurement of transmittance and refractive index of a cover substrate coated with a low reflection hardness coating agent according to an embodiment of the present invention.
3 is a cross-sectional view illustrating a touch panel integrated type display device to which a low reflection hardness coating agent according to an embodiment of the present invention is applied.

In the present invention, in order to improve the outdoor visibility, it is desired to coat the high-hardness low-refractive (low reflection) coating agent on the top of the cover substrate to reduce external light reflection and improve brightness.

The refractive index can be reduced by dispersing low refractive inorganic particles (MgF ₂ , CaF ₂ ) between the high hardness binders, but it is not preferable because it has a trade-off property in which the hardness is lowered. Accordingly, the present invention proposes a low reflection hardness coating agent having a hardness low refractive index by dispersing a polymer additive having a backbone such as a high hardness binder in a high hardness binder.

The low reflection hardness coating agent according to the present invention secures a low refractive hardness property by using a fluorine-substituted polymer surfactant (Surfactant). The low reflection hardness coating agent according to the present invention includes a hardness binder, a low refractive polymer surfactant, and a low temperature calcination solvent.

The high hardness binder contains 10 wt% to 20 wt% of a siloxane compound constituting the network by mixing polysiloxane and high-strength silica as shown in the following chemical formula 1 for hardness of 7H or more. Further, it may further contain a urethane acrylate such as the following chemical formula (2).

≪ Formula 1 >

Siloxane

(2)

Urethane acrylate

In order to match with a high hardness binder, a fluorine-substituted polymer surfactant (Surfactant) represented by the following chemical formula 3 using a binder backbone is added in an amount of 10 wt% About 20 wt%.

(3)

PerFluoroPolyEthers

In the above formula (3), n and m are within 1 to 10.

As shown in Formula 4 below, the surfactant may have a structure in which ultraviolet (UV) curing agent and thermosetting agent are bonded to both sides of a PFPE (PerfluoroPolyEthers) backbone having a backbone such as a high hardness binder.

≪ Formula 4 >

The PFPE of Formula 3 is prepared by a conventional method according to Reaction Scheme 1 below.

<Reaction Scheme 1>

As the solvent, it is preferable to use an add-on type in which the cover substrate is attached to the touch panel and a touch panel in which the cover substrate is used in a modified add-on type in which the cover substrate is used as the upper substrate of the touch panel. And contains an alcoholic solvent having low-temperature firing characteristics at 60 wt% to 80 wt%.

As described above, the high-hardness low-reflection coating agent according to the present invention is obtained by mixing a high-hardness binder having a refractive index of about 1.5 to 1.6 with a fluorine-substituted high molecular weight surfactant having a low refractive index of 1.3 or less (1.2 to 1.3) As shown in the graph of hardness-reflection characteristic shown in FIG. 1, it can have a high hardness in the range of 7H to 9H and a low refractive index in the range of 1.2 to 1.5. In addition, the high hardness low reflection coating agent of the present invention has a high transparency characteristic of a nano ceramic hybrid type. The low hardness low reflection coating agent according to the present invention is coated on the surface of the cover substrate.

Table 1 below shows the result of measuring the reflectance by coating the cover glass with the low reflection hardness coating agent according to the present invention. To measure only the reflection from the surface of the cover glass, attach two polarizers with an absorption axis of ± 90 ° to the back of the cover glass, and attach JCR-100 (parallel light) and detector (PR-705) And the reflectance of each sample was measured based on the reflection of a standard reflector.

Reflection luminance reflectivity Standard reflector 3144nit - Cover glass 139.3nit 4.43% Coated glass coated with coating A 124.4nit 3.96% Cover glass coated with coating agent B 117.5nit 3.74% Cover glass coated with coating agent C 135.9nit 4.32%

Referring to Table 1, it can be seen that the cover glass coated with the low reflection hardness coating agent according to the present invention has lower reflection brightness and reflectance than the cover glass not coated with the coating agent.

FIGS. 2A and 2B are graphs showing the results of measurement of the transmittance and the refractive index of the cover glass coated with the low reflection hardness coating agent according to the present invention. Referring to FIG. 2A, it can be seen that even if a low reflection hard coat agent is coated on a cover glass, it has a high transmittance of 99.79% at all visible wavelengths and a low refractive index of 1.3 or more and a refractive index of less than 1.41 .

3 is a cross-sectional view of a touch panel integrated type display device using a high hardness low reflection coating agent according to an embodiment of the present invention.

3 includes a display panel 10, a touch panel 30 attached on the display panel 10 by a first adhesive layer 20, and a touch panel 30 on the touch panel 30. [ And a cover substrate (50) attached by a second adhesive layer (30).

As the display panel 10, a flat panel display panel such as a liquid crystal panel, an organic light emitting diode display panel, or a plasma display panel is used. For example, when a liquid crystal panel is used as the display panel 10, the display panel 10 includes a lower substrate on which a thin film transistor array including thin film transistors and pixel electrodes is formed, a color filter array including a black matrix and a color filter A liquid crystal layer formed between the upper and lower substrates, an upper and lower polarizer plates respectively attached to outer surfaces of the upper and lower substrates, and a backlight unit positioned below the lower polarizer. The common electrode is formed on the lower substrate or the upper substrate. The liquid crystal layer is driven by a vertical electric field such as a TN (Twisted Nematic) mode or VA (Vertical Alignment) mode, or by a horizontal electric field such as an IPS (In-Plane Switching) mode or an FFS (Fringe Field Switching) mode.

As the touch panel 30, a photo touch sensor, a resistive touch sensor, or a capacitive touch sensor can be used. The photo touch sensor recognizes the touch according to the light intensity by using the phototransistor. The capacitive touch sensor recognizes the touch according to the capacitive variable. The resistive film touch sensor recognizes the touch according to the voltage change generated by the contact of the upper and lower resistive films by the touch pressure.

As the cover substrate 50, reinforced glass or transparent polymer plastic is used. Further, the surface of the cover substrate 50 is coated with the above-mentioned hardness low-reflective coating agent 52 described above. The high hardness low reflection coating agent (52) secures the low refractive hardness property by using a fluorine-substituted polymer surfactant (Surfactant). The high hardness low reflection coating agent (52) is characterized by a high hardness binder having a content ratio ranging from 10 wt% to 20 wt%, a low refractive high molecular weight surfactant having a content ratio ranging from 10 wt% to 20 wt%, and a content ranging from 60 wt% to 80 wt% Lt; RTI ID = 0.0 &gt; ratio. &Lt; / RTI &gt; As the high hardness binder, a siloxane compound, Urethane acrylate, which forms a network by mixing polysiloxane and high-strength silica is used. The low refractive polymer surfactant has a low refractive index and PFPE (PerFluoroPolyEthers) having a backbone such as a high hardness binder is used for matching with a high hardness binder. As the solvent, an alcoholic solvent having a low-temperature baking property of 150 DEG C or less is used. The high hardness low reflection coating agent 52 has a high transparency characteristic of a nanoceramic hybrid type.

The touch panel 30 is attached on the display panel 10 by the first adhesive layer 20 applied to the front surface of the display panel 10. [ The cover substrate 50 is attached on the touch panel 30 by the second adhesive layer 40 applied to the front surface of the touch panel 30. [ As the first and second adhesive layers 20, SVR (Super Viewing Resin), which is an optical elastic resin such as acrylic ultraviolet curable resin, is used. SVR improves visibility and has impact resistance.

As described above, by coating the cover substrate 50 with a high-hardness low-reflective coating agent containing a polymeric fluorine additive, external light reflection can be prevented, outdoor visibility can be improved, and high hardness can be maintained.

10: display panel 20: first adhesive layer
30: touch panel 40: second adhesive layer
50: Cover substrate 52: Low reflection hard coat agent

Claims (7)

A high hardness binder having a content ratio of 10 wt% to 20 wt% constituting a network of polysiloxane and high strength silica hybrid;
A backbone such as the high hardness binder, and a fluorine-substituted polymer having a structure in which an ultraviolet hardening agent and a thermosetting agent are bonded to both sides of the backbone, and a refractive index lower than the refractive index of the high hardness binder, A low refractive surfactant in a content ratio of 20% to 20%;
A low reflection hardness coating agent having a high hardness in a range of 7H to 9H and a low refractive index in a range of 1.2 to 1.5, including a solvent having a content of 60 wt% to 80 wt% in a low temperature baking property. The method according to claim 1,
The low refractive surfactant
Below, including PFPE (PerFluoroPolyEthers) represented by formula (1), the high hardness of the PFPE backbone, such as a binder _{"-CH 2 CF 2 O - [} - (CF 2 CF 2 O) m - (CF 2) O n -CF 2 CH ₂ - &quot;.< / RTI &_gt;
&Lt; Formula 1 &gt;

Where n and m are in the range of 1 to 10. The method according to claim 1,
Wherein the high hardness binder further comprises a urethane acrylate. The method according to claim 1,
Wherein the refractive index of the high hardness binder is in the range of 1.5 to 1.6, which is larger than the refractive index of the low reflection hardness coating agent. The method according to claim 1,
Wherein the solvent comprises an alcoholic solvent which is fired at a temperature of 150 DEG C or lower. A display module in which a touch sensor is integrated;
And a cover substrate coated with the low reflection hardness coating agent according to any one of claims 1 to 5 attached to the display module. The method of claim 6,
The display module
A display panel which is one of a liquid crystal panel and an organic light emitting diode display panel,
And a touch panel attached to the display panel by a first adhesive layer,
Wherein the cover substrate is attached to the touch panel by a second adhesive layer.

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