KR20160027858A

KR20160027858A - Polarization plate combined with touch sensing patterns

Info

Publication number: KR20160027858A
Application number: KR1020140116494A
Authority: KR
Inventors: 송제훈
Original assignee: 동우 화인켐 주식회사
Priority date: 2014-09-02
Filing date: 2014-09-02
Publication date: 2016-03-10

Abstract

The present invention relates to a touch sensing pattern-integrated polarization plate and, more specifically, to a touch sensing pattern-integrated polarization plate and a touch screen panel including the same, capable of having an excellent optical property without the degradation of front and side contrast. The present invention relates to a touch sensing pattern-integrated polarization plate includes: a polarization plate formed on the top of a first base film; and a second base film attached to the bottom of the first base film by adhesive. The first base film and the second base film independently have an optical axis of ±0.5° in a base direction (MD direction).

Description

TECHNICAL FIELD [0001] The present invention relates to a polarizing plate integrated with a touch sensing pattern,

More particularly, the present invention relates to a touch-sensitive pattern integrated polarizer having excellent optical characteristics by using a base film having a specific optical axis value, and a touch screen having the touch-sensitive pattern integrated polarizer.

In the liquid crystal display device, light emitted from a back light, which is a light source, passes through a liquid crystal having anisotropy and a pair of polarizing plates disposed vertically to each other, so that a good image can be obtained in front of the liquid crystal display device, , The display performance is deteriorated. In order to improve the black display state (black characteristic), the side contrast ratio (CR), the color shift, and the like of the liquid crystal display device and to reduce the viewing angle dependency, a retardation film is used. Since the retardation film has a function of converting linearly polarized light into elliptically polarized light or circularly polarized light or converting linearly polarized light in a certain direction into another direction, it is possible to improve the viewing angle, brightness, contrast, etc. of the liquid crystal display device .

In order to solve the problem of deterioration in optical characteristics due to birefringence of a liquid crystal cell even in a liquid crystal display using a VA mode liquid crystal cell, a plurality of retardation films are used to adjust the polarization state of light passing through the liquid crystal layer, In the case of using a VA mode liquid crystal cell in manufacturing a touch screen, a plurality of retardation films are used for improving optical characteristics.

On the other hand, in manufacturing a touch screen, a separate base film is used to form the touch sensing electrode, and a non-oriented film is usually used to prevent deterioration of optical characteristics due to the base film. However, even in the case of a non-oriented film, the front black brightness controlled by the retardation film increases again due to the inherent optical axis and the in-plane retardation (Ro) of the non-oriented film, and the front and side contrast ratios decrease.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polarizing plate integrated with a touch sensing pattern having excellent optical characteristics.

Another object of the present invention is to provide a polarizing plate integrated with a touch sensing pattern capable of realizing a thin film structure.

1. polarizer;

A first base film disposed below the polarizer and having a first sensing pattern attached to one surface thereof; And

And a second base film disposed at a lower portion of the first base film and having a second sensing pattern attached to one surface thereof,

Wherein the first base film and the second base film independently have an optical axis of +/- 0.5 DEG in the MD direction of the base film.

2. The polarizing plate according to 1 above, wherein the sum of the in-plane retardation values (Ro) of the first base film and the second base film is 30 to 80 nm.

3. The polarizing plate integrated with a touch detection pattern attached to a VA (Vertical Alignment) mode liquid crystal cell,

4. A touch screen comprising the touch-sensitive pattern integral polarizer according to any one of items 1 to 3 above.

5. In the above 4,

A VA mode liquid crystal cell;

The touch sensing pattern integrated polarizer of any one of items 1 to 3 arranged above the liquid crystal cell. And

A lower polarizer disposed under the liquid crystal cell;

.

6. The touch screen according to 5 above, wherein the sum of the in-plane retardation values (Ro) of the first base film and the second base film is 40 to 80 nm.

7. In the above 4,

A VA mode liquid crystal cell;

The touch sensing pattern integrated polarizer of any one of claims 1 to 3, which is disposed on the liquid crystal cell. And

A lower polarizer and a retardation film disposed under the liquid crystal cell;

.

8. The touch screen according to 7 above, wherein the sum of the in-plane retardation values (Ro) of the first base film and the second base film is 30 to 70 nm.

9. The touch screen according to 7 above, wherein the in-plane retardation (Ro) of the retardation film disposed under the liquid crystal cell is 30 to 70 nm.

The touch-sensitive pattern integrated polarizer of the present invention has excellent optical characteristics because there is no decrease in front and side contrast ratio by using a base film having a specific optical axis value.

In addition, since the touch pattern integrated polarizer of the present invention does not use a separate retardation film, a thin film structure can be achieved.

1 and 2 are schematic vertical cross-sectional views of a touch-sensitive pattern integrated polarizer and a touch screen including the same according to an embodiment of the present invention.
3 is a schematic vertical cross-sectional view of a touch screen according to Comparative Example 1. FIG.

[0001] The present invention relates to a polarizing plate integrated with a touch sensing pattern, and more particularly, A first base film disposed below the polarizer and having a first sensing pattern attached to one surface thereof; And a second base film disposed at a lower portion of the first base film and having a second sensing pattern attached to one surface thereof, wherein the first base film and the second base film are each independently formed of MD Sensitive polarizing plate having an optical axis of +/- 0.5 deg. In the direction of the liquid crystal display panel without deteriorating the front and side contrast ratio, and a touch screen having the same.

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

FIG. 1 schematically illustrates a touch-sensitive pattern integrated polarizer according to an exemplary embodiment of the present invention and a touch screen including the same.

The touch sensing electrode integrated polarizer of the present invention comprises a polarizer 110; A first base film (200) disposed under the polarizer (110) and having a first sensing pattern (210) attached to one surface thereof; And a second base film 300 disposed on the lower surface of the first base film 200 and having a second sensing pattern 310 on one surface thereof.

In the present invention, the term " upper side " means the side of the viewer on the basis of the reference member, and the term " lower side "

Conventionally, in order to solve the problem of deterioration of optical characteristics due to birefringence of a liquid crystal cell in a liquid crystal display device using a VA mode liquid crystal cell, a plurality of retardation films are used to adjust the polarization state of light passing through the liquid crystal layer, And so on.

In the manufacture of a touch screen, when a VA mode liquid crystal cell is used, a plurality of retardation films are used to improve the optical characteristics. However, due to the optical axis inherent to the base film used for forming the touch sensing electrode, There is a problem that the front side Black luminance increases again and the contrast ratio of the front side and the side is lowered.

Accordingly, in the present invention, by using a base film having an optical axis with a certain range of angles, the optical characteristics of light passing through the liquid crystal layer can be controlled to reduce the front and side contrast ratios, do.

The first base film 200 and the second base film 300 according to the present invention each have an optical axis of ± 0.5 ° in the MD direction of the base film so that the contrast ratio of the front side and the side face is not reduced Further, since the polarizing plate of the present invention includes the base films, the retardation film does not need to be used separately, and thus a thin film structure of the polarizing plate can be realized.

The retardation value (Ro) of the first base film and the second base film is not particularly limited. For example, the sum of the retardation values may be 30 to 80 nm, preferably 30 to 70 nm, A preferred example may be 40 to 80 nm. The in-plane retardation value (Ro) of each of the first base film and the second base film is not particularly limited as long as the sum is within the above-mentioned range. When the base films satisfy the in-plane retardation value (Ro) in the above range, it is judged that the front and side black brightness can be effectively controlled.

The retardation value (Rth) in the thickness direction of the first base film and the second base film is not particularly limited. For example, the sum of the retardation values may be 100 to 300 nm, preferably 110 to 150 nm , And another preferred example may be 240 to 280 nm. The retardation value (Rth) in the thickness direction of each of the first base film and the second base film is not particularly limited as long as the sum is within the above-mentioned range. It is judged that the front and side black brightness can be effectively controlled when the base film satisfies the thickness direction retardation value (Rth) in the above range.

The kind of the first base film and the second base film according to the present invention are not particularly limited as long as they satisfy the above-mentioned physical properties. For example, a protective film of a polarizer described later can be used.

The angle of the optical axis of the first base film and the second base film according to the present invention can be controlled by a method known in the art, for example, by controlling the stretching ratio in the production of a film.

The thicknesses of the first base film and the second base film according to the present invention are not particularly limited, but may be, for example, 50 to 150 占 퐉, preferably 80 to 120 占 퐉. When the above range is satisfied, it is preferable from the viewpoint of ensuring mechanical properties.

As the polarizer 110 according to the present invention, a polarizer used in the art can be used without any particular limitation, and a polymer solution containing a polymer resin and a dichroic substance can be directly coated on a substrate to form a coating layer. The coating layer polarizer can be preferably used when the polarizing plate is formed of a single polarizer layer.

As the polymer resin for forming the polarizer coating layer, for example, a polyvinyl alcohol-based resin may be typically used. The polyvinyl alcohol-based resin is preferably a polyvinyl alcohol-based resin obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Other monomers copolymerizable with vinyl acetate include acrylamide monomers having an unsaturated carboxylic acid type, an unsaturated sulfonic acid type, an olefin type, a vinyl ether type, and an ammonium group.

The polyvinyl alcohol-based resin may be modified or may be polyvinyl formal or polyvinyl acetal modified with, for example, aldehydes.

A polarizer layer can be formed by mixing a dichroic material with such a polyvinyl alcohol-based resin and forming a film.

The polarizer 110 may further include a protective film on the polarizer 110. As the protective film usable in the present invention, a film excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like can be used. Specific examples include polyester resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate and polybutylene terephthalate; Cellulose-based resins such as diacetylcellulose and triacetylcellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin resins such as polyethylene, polypropylene, cyclo- or norbornene-structured polyolefins, ethylene-propylene copolymers; Vinyl chloride resin; Amide resins such as nylon and aromatic polyamide; Imide resin; Polyether sulfone type resin; Sulfone based resin; Polyether ether ketone resin; A sulfided polyphenylene resin; Vinyl alcohol-based resin; Vinylidene chloride resins; Vinyl butyral resin; Allylate series resin; Polyoxymethylene type resin; Epoxy resin, and the like, and a film composed of the blend of the thermoplastic resin may also be used. Further, a film made of a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, or silicone or a film made of an ultraviolet curable resin may be used. The content of the thermoplastic resin in the polarizer protective film is preferably 50 to 100% by weight, preferably 50 to 99% by weight, more preferably 60 to 98% by weight, and most preferably 70 to 97% by weight. When the content is less than 50% by weight, the inherent high transparency of the thermoplastic resin may not be sufficiently exhibited. Such a transparent protective film may contain one or more suitable additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment and a colorant.

Further, if necessary, the protective film may be surface-treated. Examples of the surface treatment include a chemical treatment such as an alkaline treatment including a dry treatment such as a plasma treatment, a corona treatment, a primer treatment, and a saponification treatment.

In order to sense a touch position on a plane of a touch screen, an electrode pattern (for example, an x-coordinate, a y-axis, Two types of electrode patterns, that is, an electrode pattern 210 for sensing the y coordinate and a electrode pattern 310 for sensing the y coordinate are required, so that the touch sensing pattern includes two kinds of electrode patterns 210 and 310.

The present invention includes a first touch sensing pattern 210 attached to one side of the first base film 200 and a second touch sensing pattern 310 attached to one side of the second base film 300.

The first sensing pattern 210 and the second sensing pattern 310 are arranged in different directions to provide information on the X coordinate and the Y coordinate of the touched point. Specifically, when a human hand or an object touches the transparent substrate, a change in capacitance due to the contact position toward the driving circuit via the first sensing pattern 210, the second sensing pattern 310, . Then, the contact position is grasped by the change of the electrostatic capacitance by the X and Y input processing circuit (not shown) or the like and converted into an electrical signal.

The first sensing pattern 210 and the second sensing pattern 310 of the touch sensing electrode can be used without limitation in materials used in the art. In order not to impair the visibility of the image displayed on the screen, a transparent material is used Or formed in a fine pattern. Specific examples thereof include indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), fluorine tin oxide (FTO) (ATO), a conductive polymer, a carbon nanotube (CNT), a graphene, a metal wire, and a metal thin film. These may be used alone or in combination of two or more.

The conductive polymer includes a polythiophene-based polymer such as poly (3,4-ethylenedioxythiophene) (PEDOT), a PSS (poly (styrene sulfonate)) -based polymer, and a polyaniline-based polymer. These may be used alone or in combination of two or more.

The metal used for the metal wire is not particularly limited, and examples thereof include silver (Ag), gold, aluminum, copper, iron, nickel, titanium, tellurium, chromium and the like. These may be used alone or in combination of two or more.

The metal used for the metal thin film is a metallic material having a low specific resistance value and is made of a material such as silver (Ag), gold, aluminum, copper, platinum, molybdenum, palladium, neodymium, silver-palladium- . These may be used alone or in combination of two or more. Also, the metal thin film may be formed into a net structure having a fine line width in consideration of light transmittance and pattern visibility.

The touch-sensitive-electrode-integrated polarizing plate having the base film having the specific optical axis value described above may be attached to a VA (Vertical Alignment) mode liquid crystal cell.

The present invention relates to a touch screen including the above-described touch-sensitive-pattern integrated polarizer (100).

According to an embodiment of the present invention, a touch screen according to the present invention includes a liquid crystal cell 400; A touch sensing pattern integrated polarizer 100 disposed on the liquid crystal cell 400 according to the present invention; And a lower polarizer 120 disposed under the liquid crystal cell (see Figs. 1 (a) and 1 (b)).

In this case, since the first base film and the second base film of the polarizing plate 100 satisfy the aforementioned optical axis value, in-plane direction retardation and thickness direction retardation, birefringence of light passing through the liquid crystal cell can be effectively controlled, Can also be realized.

The birefringence of light passing through the liquid crystal cell (see Fig. 1 (b)) can be prevented even when only a protective film (zero-retardation film) is used In this case, the sum of the in-plane retardation values (Ro) of the first base film and the second base film of the polarizing plate may be more preferably 40 to 80 nm, and the sum of the in- 2 retardation value (Rth) in the thickness direction of the base film may more preferably be 240 to 280 nm. When the base films satisfy the retardation values (Ro, Rth) in the above-mentioned range, it is judged that the front and side Black luminances can be effectively controlled.

According to another embodiment of the present invention, the liquid crystal cell 400 may further include a retardation film 500 below the liquid crystal cell 400 (see FIG. 2).

In this case, the sum of the in-plane retardation values (Ro) of the first base film and the second base film of the polarizing plate may be more preferably 30 to 70 nm, and the sum of the in- The sum of the retardation values (Rth) may more preferably be 110 to 150 nm. When the base films satisfy the retardation values (Ro, Rth) in the above-mentioned range, it is judged that the front and side Black brightness can be effectively controlled in addition to the birefringence control effect by the retardation film.

In addition, the in-plane retardation value Ro of the lower phase difference film 500 of the liquid crystal cell 400 is not particularly limited, but may be, for example, 30 to 70 nm. The thickness direction retardation value (Rth) of the lower phase difference film (500) is not particularly limited, but may be, for example, 110 to 150 nm.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.

Example And Comparative Example

(One) Example One

A COP film was used as a base material for forming the touch-sensitive pattern, and a first base film having an optical axis in the MD direction of 0.1 deg., Ro of 26 nm, and Rth of 62.5 nm was produced through a stretching process. A first touch-sensitive pattern was formed on the first base film, respectively, and then bonded to a polarizer.

A second base film was prepared in the same manner as in the first base film, a second touch sensing pattern was formed on the second base film, and the first base film was bonded to the first base film bonded to the polarizer, Thereby producing an integral polarizing plate.

The prepared polarizer was attached to the upper part of the VA mode liquid crystal cell using a pressure sensitive adhesive, and a polarizing plate having a polarizer bonded with a retardation film having a thickness of 52 nm and an Rth of 125 nm was attached to the lower part of the liquid crystal cell 2).

(2) Example 2

The first base film in which the optical axis in the MD direction was 0.1 deg., Ro was 20 nm and Rth was 48 nm, the second base film in which the optical axis in the MD direction was 0.1 deg., Ro was 32 nm, and Rth was 77 nm was used. The touch screen was manufactured in the same manner as in the above.

(3) Example 3

A second base film having an optical axis in the MD direction of 0.1 deg., Ro of 32.5 nm and Rth of 130 nm, an optical axis in the MD direction of 0.1 deg., Ro of 32.5 nm and Rth of 130 nm, Sensitive polarizing plate was manufactured in the same manner as in Example 1, except that the retardation film of Comparative Example 1 was not used.

Thereafter, a polarizing plate having a protective film (zero-retardation film) bonded to a polarizer was attached to the upper part of the VA mode liquid crystal cell using a pressure-sensitive adhesive on the prepared polarizing plate, and a touch screen was manufactured b)).

(4) Example 4

A first base film in which the optical axis in the MD direction was 0.3 deg., Ro was 26 nm and Rth was 62.5 nm, a second base film in which the optical axis in the MD direction was 0.3 deg., Ro was 26 nm, and Rth was 62.5 nm was used A touch screen was manufactured in the same manner as in Example 1.

(5) Example 5

A first base film having an optical axis in the MD direction of 0.5 deg., Ro of 26 nm and Rth of 62.5 nm, a second base film having an MD optical axis of 0.5 deg., Ro of 26 nm and Rth of 62.5 nm was used A touch screen was manufactured in the same manner as in Example 1.

(6) Comparative Example One

A touch detection pattern is formed on two sheets of unoriented COP films having an optical axis in the MD direction of 20 DEG, Ro in a thickness of 4 nm and Rth in a thickness of 3.5 nm, and a polarizing plate having a Ro film of 52 nm and a Rth of 125 nm, (See Fig. 3). The results are shown in Table 3. < tb >< TABLE >

Test Methods

(1) front and side Black Brightness and Color difference (Front and side x, y Color coordinates Difference) measurement

The black brightness and chrominance (difference between the x and y chromaticity coordinates of the front and the side) of the front and the side of the touch screen manufactured in Examples and Comparative Examples were measured through TOPCON spectroscopic radiation system (SR-3A) 1.

Reference is a touch screen in which a polarizer in which a retardation film having Ro of 52 nm and Rth of 125 nm is bonded to a polarizer is attached to the upper and lower portions of the VA liquid crystal cell, respectively.

division Front Black Luminance Side Black Luminance Color difference Reference 0.124 33.73 0.12 Comparative Example 1 0.742 47.49 0.16 Example 1 0.124 34.48 0.12 Example 2 0.124 34.49 0.12 Example 3 0.124 32.36 0.05 Example 4 0.125 34.48 0.12 Example 5 0.126 34.48 0.12

Referring to Table 1, it can be seen that the touch screen using the polarizing plate according to the present invention exhibits excellent optical characteristics comparable to those of the reference having the optical characteristics corrected using only the retardation film.

In the case of the comparative example, it was confirmed that the optical characteristics were remarkably lowered by the intrinsic optical axis and the in-plane retardation value of the base film on which the touch-sensitive pattern was formed, as compared with the examples.

Claims

A polarizer;
A first base film disposed below the polarizer and having a first sensing pattern attached to one surface thereof; And
And a second base film disposed at a lower portion of the first base film and having a second sensing pattern attached to one surface thereof,
Wherein the first base film and the second base film independently have an optical axis of +/- 0.5 DEG in the MD direction of the base film.

The polarizer of claim 1, wherein the sum of the in-plane retardation values (Ro) of the first base film and the second base film is 30 to 80 nm.

The polarizing plate according to claim 1, wherein the polarizing plate is attached to a VA (Vertical Alignment) mode liquid crystal cell.

A touch screen comprising the touch-sensitive pattern integrated polarizer according to any one of claims 1 to 3.

The method of claim 4,
A VA mode liquid crystal cell;
The touch sensing pattern integrated polarizer of any one of claims 1 to 3, which is disposed on the liquid crystal cell. And
A lower polarizer disposed under the liquid crystal cell;
.

The touch screen according to claim 5, wherein the sum of the in-plane retardation values (Ro) of the first base film and the second base film is 40 to 80 nm.

The method of claim 4,
A VA mode liquid crystal cell;
The touch sensing pattern integrated polarizer of any one of claims 1 to 3, which is disposed on the liquid crystal cell. And
A lower polarizer and a retardation film disposed under the liquid crystal cell;
.

The touch screen according to claim 7, wherein the sum of the in-plane retardation values (Ro) of the first base film and the second base film is 30 to 70 nm.

The touch screen according to claim 7, wherein the in-plane retardation (Ro) of the retardation film disposed under the liquid crystal cell is 30 to 70 nm.