KR20190060472A - Polarizer plate and method for manufacturing the same and display device comprising the same - Google Patents

Abstract

The present invention relates to a polarizing plate, a manufacturing method of the same, and a display apparatus including the same. More specifically, the polarizing plate comprises: an isotropic film layer; a polarizer layer formed by coating a lyotropic liquid crystal on one surface of the isotropic film layer; and a phase difference layer formed by coating a reactive liquid crystal compound on an uncoated surface of the polarizer layer. By bonding the isotropic film, the polarizer layer, and the phase difference layer without a separate adhesive material or adhesive film, the thickness of the polarizing plate is greatly reduce compared to the conventional polarizer, and the bending degree of each layer when bent is kept uniform.

Description

TECHNICAL FIELD [0001] The present invention relates to a polarizing plate, a method of manufacturing the same, and a display device including the polarizing plate.

The present invention relates to a polarizing plate, a method of manufacturing the same, and a display device including the polarizing plate. More particularly, the present invention relates to a polarizing plate, a polarizer layer, and a retardation layer bonded to each other without a separate adhesive or adhesive film, And a method of manufacturing the polarizer, and a display device including the polarizer.

Organic light emitting display (OLED) display devices have recently attracted attention as a next generation display device because of their advantages such as wide viewing angle, quick response speed and low power consumption compared to CRT (Cathode Ray Tube) and LCD (Liquid Crystal Display).

When the OLED display device interferes with the light emitted from the self-emission and the external natural light reflected from the inner reflection plate, the performance of the display device deteriorates. Therefore, a thick and rigid polarizer is used to suppress the display performance.

In recent years, studies on thin and bendable flexible displays have been actively carried out, and accordingly, polarizers are also required to have bending properties and thin thicknesses.

However, since the polarizing plate used in conventional LCDs is manufactured by the stretching method and has a thickness of 240 to 260 탆, it is difficult to maintain the degree of warpage of each layer uniformly when the polarizing plate is bent. For example, as shown in FIG. 1, a curved display or a foldable display including a conventional polarizing plate can not be uniformly warped when bent.

Therefore, it is required to manufacture a thin and bendable polarizing plate to solve the above problems.

Korean Patent Publication No. 2013-0108276

In order to solve the problems of the related art as described above, the present invention provides a polarizing plate, a polarizer layer and a retardation layer which are bonded to each other without a separate adhesive or an adhesive film, And to provide a polarizing plate which is uniformly maintained, a method for manufacturing the same, and a display device including the same.

In order to accomplish the above object, the present invention provides an optical film comprising an isotropic film layer; A polarizer layer formed by coating a lyotropic liquid crystal on one surface of the isotropic film layer; And a retardation layer formed by coating a non-coated surface of the polarizer layer with a reactive liquid crystal compound.

The present invention also provides a method of manufacturing a liquid crystal display comprising the steps of: a) coating a water-based lyotropic liquid crystal on one surface of an isotropic film and drying to form a polarizer layer; And b) coating and drying an organic solvent-based reactive liquid crystal compound on the uncoated side of the polarizer layer to form a retardation layer.

The present invention also provides a display device comprising the polarizer of the present invention.

According to the present invention, there is provided a polarizing plate in which an isotropic film, a polarizer layer, and a retardation layer are bonded without a separate adhesive or an adhesive film, and the degree of warpage of each layer is uniformly maintained when the film is bent while remarkably reducing its thickness as compared with a conventional polarizer, There is an effect of providing a display device including the same.

1 is a schematic view of a conventional flexible display.

Hereinafter, the polarizing plate of the present invention, a method of manufacturing the same, and a display device including the polarizing plate will be described in detail.

The present inventors have found that when a polarizer or a polarizer layer belonging to a polarizing plate is formed by coating using a lyotropic liquid crystal rather than a conventional stretching method, a separate adhesive layer can be omitted, It is confirmed that the degree of warpage of each layer is uniformly maintained when bent while being bent.

The polarizing plate of the present invention comprises an isotropic film layer; A polarizer layer in which a lyotropic liquid crystal is coated on one surface of the isotropic film layer; And a retardation layer formed by coating a non-coated surface of the polarizer layer with a reactive liquid crystal compound.

Hereinafter, the polarizer of the present invention will be described in detail for each layer.

Isotropic  Film layer

The isotropic film of the present invention is not limited as long as it is a film capable of protecting the polarizer layer without affecting the retardation, and for example, a polyolefin resin, a polyester resin, a cellulose resin, a polycarbonate resin, an acrylic resin, , Polyvinyl chloride resins, amide resins, polyether sulfone resins, sulfone resins, polyether sulfone resins, polyether ether ketone resins, sulfided polyphenylene resins, vinyl alcohol resins, vinylidene chloride resins, vinyl butyral resins, , A polyoxymethylene resin, and an epoxy resin. Preferably, it is a cellulose resin, more preferably triacetate cellulose (TAC). In this case, the polarizer layer is protected.

The isotropic film layer may be, for example, 10 to 125 占 퐉, or 50 to 125 占 퐉. Within this range, it is advantageous to reduce the thickness of the polarizing plate and has an excellent mechanical strength.

In the present description, the thickness is measured using Mitutoyo's ABS LUTE thickness meter.

Polarizer  layer

The polarizer layer of the present invention can be formed, for example, by coating a lyotropic liquid crystal on one surface of the isotropic film layer. In this case, an existing stretching method in which a dichroic substance such as iodine or a dichroic dye is absorbed and drawn on a hydrophilic polymer film The polarizing layer is formed by a coating method, which is advantageous for thinning of the polarizing plate.

The lyotropic liquid crystal may be, for example, an aqueous lyotropic liquid crystal. In this case, the lyotropic liquid crystal is easy to coat and maintains a thin polarizer layer.

In the present description, the term "water egg" refers to a property of dissolving or homogeneously mixing water in water, including not only dissolving in water or homogeneous mixing but also dissolving or mixing in both organic solvent and water.

The water-based lyotropic liquid crystal may further include additives such as a plasticizer, a coupling agent, and an antistatic agent, which are generally used in the art within a range that does not impair the desired effects of the present invention.

The thickness of the polarizer layer may be, for example, 4 to 100 mu m, 4 to 60 mu m, or 10 to 30 mu m. There is an advantageous effect in reducing the thickness of the polarizing plate within this range.

Phase difference  layer

The retardation layer of the present invention can be formed, for example, by coating a reactive liquid crystal compound on a surface not coated with the polarizer layer, and in this case, retardation of light passing through the polarizer layer is appropriately delayed.

The reactive liquid crystal compound may be, for example, a non-water-based reactive liquid crystal compound. In this case, a uniform thin film may be formed.

In the present description, non-aqueous eggs are not excluded from the meaning that they do not dissolve in the water, and that they are naturally contained by the raw material of the solvent for dissolving the solute.

The reactive liquid crystal compound may be, for example, a reactive mesogen. In this case, the reactive liquid crystal compound can be uniformly oriented in a desired direction, and the formed layer has polarizing properties.

The reactive mesogen may be, for example, a monomer molecule having a liquid crystal phase including a mesogen capable of exhibiting liquid crystallinity and a terminal functional group capable of polymerization. In this case, the reactive liquid crystal may be uniformly oriented in a desired direction And the formed layer has an effect of obtaining polarization characteristics.

The retardation layer may include a first retardation layer and a second retardation layer having a 90 ° optical axis and the first retardation layer, and at least one of the first retardation layer and the second retardation layer may be formed by coating a reactive liquid crystal compound In this case, there is an effect of improving luminance and preventing reflection.

The reactive liquid crystal compound may be, for example, the above-described reactive liquid crystal compound. In this case, a uniform thin film is formed.

The thickness of the retardation layer may be, for example, 15 to 200 占 퐉, 30 to 150 占 퐉, or 50 to 125 占 퐉, which is advantageous in reducing the thickness of the polarizing plate within this range.

Other floors

For example, a hard-coating layer may be formed on the other surface of the isotropic film layer. In this case, cracks may be formed on the surface of the polarizer and the dimensional change may be prevented.

The hard coating layer may be formed using an ultraviolet curable resin, for example. In this case, cracks are generated on the surface of the polarizing plate and the effect of preventing the dimensional change is prevented.

The thickness of the hard coating layer may be, for example, 2 to 50 탆, 5 to 40 탆, or 10 to 30 탆, which is advantageous in reducing the thickness of the polarizing plate within this range.

The isotropic film layer may further include a functional layer on one surface thereof. In this case, cracks are generated on the surface of the polarizer and the effect of preventing the dimensional change is prevented.

The functional layer may include at least one layer selected from the group consisting of an anti-reflection layer, an anti-glare layer, and an anti-static layer.

The anti-glare layer has an effect of preventing light (external light) incident from the outside from being reflected and obstructing the visibility of the transmitted light. The anti-glare layer induces diffusion and reflection of light incident from outside to prevent glare The antistatic layer has the effect of preventing the deformation and the function of the elements inside the display device from being deteriorated by dispersing the static electricity which may occur in the process or daily life.

For example, the polarizing plate may have a pressure-sensitive adhesive layer formed on an uncoated surface of the retardation layer. In this case, the polarizing plate has an effect of facilitating bonding with other layers.

The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer is not limited as long as it is a pressure-sensitive adhesive used for a conventional polarizing plate.

The thickness of the pressure-sensitive adhesive layer may be, for example, 5 to 70 탆, 5 to 50 탆, or 15 to 70 탆, which is advantageous in reducing the thickness of the polarizing plate within this range.

Polarizer

The polarizing plate of the present invention may have a thickness of 5 to 300 μm, 5 to 150 μm, 5 to 60 μm, or 10 to 30 μm, for example, and has excellent effects for the polarizing plate of the OLED device within this range.

When the polarizing plate of the present invention is bent, for example, when the polarizing plate is bent under the bending test condition, the bent portion can be uniformly maintained at 1 to 10 mm (0.5 to 5 R), and in this case, the polarizing plate can be easily applied to a flexible display Can be used as a polarizing plate.

The polarizing plate of the present invention may have a transmittance of 96 to 99.99%, 97 to 99% or 96 to 99.5%, for example, and may be used within the above range for polarizing plate applications of OLED devices.

In the present description, the transmittance is measured through light of 380 to 740 nm according to KONICA MINOLTA SPECTROPHOTOMETER (CM-3600d, Japan).

Hereinafter, the method for producing the polarizing plate of the present invention will be described in detail.

Method for producing polarizer

The polarizing plate of the present invention can be manufactured by, for example, a) coating and drying a water-based lyotropic liquid crystal on one surface of an isotropic film to form a polarizer layer; And b) coating and drying the reactive liquid crystal compound based on an organic solvent on the uncoated side of the polarizer layer to form a retardation layer. In this case, since the thickness is greatly reduced as compared with the conventional polarizer, There is an effect that the degree of warpage of each layer is uniformly maintained.

a) Polarizer  Layer forming step

The water-based lyotropic liquid crystal in step a) may include, for example, a lyotropic liquid crystal and water. In this case, coating is easy and the polarizer layer is kept thin.

The lyotropic liquid crystal may be, for example, 5 to 90% by weight, 10 to 80% by weight or 20 to 50% by weight based on 100% by weight of the water-based lyotropic liquid crystal, Is maintained at a thin thickness.

The water may be, for example, from 5 to 90% by weight, from 10 to 80% by weight or from 20 to 50% by weight based on 100% by weight of the water-based lyotropic liquid crystal, coating is easy within this range, It has an effect of maintaining the thickness.

The water-based lyotropic liquid crystal in the step (a) may further include additives such as plasticizers, coupling agents, and antistatic agents generally used in the art within the range not hindering the object of the present invention have.

The coating of step a) may be, for example, a slot die coating or a spin coating. In this case, a uniform thin film may be formed.

The slot die coating is a coating method in which a liquid fluid having a flow is extruded by a slot die and applied onto a substrate film being transported.

The slot die coating is based on TSDC 180 from DCN A size of 370 mm X 470 mm, a pump injection of 10 ml / min, a rail speed of 4 m / s, and a gap of 100 탆.

The conveyance can be carried out through a conveyance belt, a conveyance rail or a conveyance roller. In this case, a uniform coating can be obtained, and conduction and heat drying through the conveyance rail or the conveyance roller can be facilitated.

The drying in the step a) may be conducted, for example, by conduction heat drying, and in this case, the coating efficiency is improved and a thin film is formed.

The conduction transfer heat drying refers to a method of heating a material by heat conduction on a surface heated by a heating medium or heat, in particular, a surface of a conveyance belt, a conveyance rail, and a conveyance roller.

The drying in step a) may be carried out at 40 to 120 ° C or 60 to 100 ° C, for example, and a film having a uniform and thin thickness may be formed within this range.

The drying in the step a) may be carried out for 1 to 15 minutes or 5 to 10 minutes, for example, and a uniform and thin film is formed within the range.

The step a) may include a surface modification process, for example, and the surface modification process may proceed in a state where the polarizer layer is dried. In this case, adhesion between the polarizer layer and the retardation layer is facilitated.

The surface modification process may be selected from the group consisting of plasma treatment, corona treatment, and e-UV, and is preferably a plasma treatment. In this case, adhesion between the polarizer layer and the retardation layer is facilitated.

The plasma treatment can be plasma treated, for example, at 100 to 2,000 J / m ² , 150 to 1,000 J / m ² , or 200 to 500 J / m ^2. Within this range, the lyotropic liquid crystal can be uniformly There is an effect that film formation of the film is easy.

The water-based lyotropic liquid crystal may have a viscosity at 25 ° C of 5 to 200 cps, 5 to 100 cps, or 10 to 50 cps, for example, and a film having a uniform thickness is formed within this range.

In the present description, the viscosity is measured on the basis of VISCOMETER DV2T manufactured by BROOKFIELD.

The reactive liquid crystal compound based on the organic solvent in the step b) may include a reactive liquid crystal compound, an organic solvent, and a dichroic dye. In this case, a uniform and thin film may be formed.

The reactive liquid crystal compound may be, for example, the above-described reactive liquid crystal compound. In this case, a uniform thin film is formed.

The reactive liquid crystal compound may be, for example, 5 to 90% by weight, 10 to 80% by weight, or 20 to 50% by weight based on 100% by weight of the organic solvent-based reactive liquid crystal compound, There is an effect that a film is formed.

The organic solvent is not particularly limited as long as it is an organic solvent capable of dissolving the reactive liquid crystal compound. Specific examples of the organic solvent include propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene and chloroform And in this case, a uniform thin film can be formed.

The organic solvent may be, for example, 5 to 90% by weight, 10 to 80% by weight, or 20 to 50% by weight based on 100% by weight of the reactive liquid crystal compound based on the organic solvent, .

The dichroic dye has a polarizing property. For example, the dichroic dye has a property of absorbance in the major axis direction and absorbance in the minor axis direction of the molecule are different from each other. In general, the dye is a dichroic dye used in the technical field of the present invention It is not limited.

The dichroic dye may be, for example, 5 to 90% by weight, 10 to 80% by weight, or 20 to 50% by weight based on 100% by weight of the reactive liquid crystal compound based on the organic solvent. Can be polymerized without interfering.

The reactive liquid crystal compound based on the organic solvent in the step b) may further include additives such as a leveling agent and a polymerization initiator generally used in the art within the range not hindering the object of the present invention .

The coating of step b) is not particularly limited as long as it is a method used in the present invention. For example, it may be at least one selected from the group consisting of fin coating, roll coating, dispensing coating and gravure coating.

The drying in step b) is not particularly limited as long as the solvent can be evaporated.

The drying in step b) may be performed at 40 to 120 ° C or 60 to 100 ° C, for example, and a uniform and thin film may be formed within this range.

The drying in the step b) may be carried out for 1 to 15 minutes or 3 to 8 minutes, for example, and a uniform and thin film is formed within the range.

The display device of the present invention may include the above-described polarizer of the present invention.

The display device is an apparatus having a display element, and includes a light emitting element or a light emitting device as a light emitting source.

In this description, the display device may be, for example, an organic light emitting diode (OLED) display device, but is not limited thereto.

The polarizing plate of the present invention can be attached to a display panel by a pressure sensitive adhesive, for example, and the pressure sensitive adhesive is not particularly limited as long as it is usually used in the technical field to which the present invention belongs.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[Example]

Example  One

A water-based lyotropic liquid crystal was coated on a 50-125 μm thick triacetate cellulose (TAC) film transferred through a transfer rail heated to 40-80 ° C. by slot die coating in a clean room condition, And then electro-conductive and heat-dried at 80 ° C for 2 to 10 minutes through the heated transfer rail. The aqueous rheotropic liquid crystal used herein was a solution prepared by mixing 5 to 90% by weight of a lyotropic liquid crystal and 5 to 90% by weight of water.

After the plasma treatment, 5 to 90% by weight of the organic solvent, 5 to 90% by weight of the reactive liquid crystal compound and 5 to 90% by weight of the dichroic dye are added to the dried film, Was coated on the plasma-treated film and dried at 60 to 100 ° C for 3 to 8 minutes to prepare a polarizing plate.

Comparative Example  One

A conventional polarizer was prepared by using a film as a polarizer and bonding it using an adhesive.

 [Test Example]

The properties of the polarizing plate prepared or prepared in Example 1 and Comparative Example 1 were measured by the following methods.

* Thickness: Measured using an ABS LUTE thickness meter from Mitutoyo.

* Thickness of the bent portion: The thickness of the bent portion was measured by bending the polarizing plate under the bending test condition.

Transmittance: Measured by light of 380 to 740 nm, according to KONICA MINOLTA SPECTROPHOTOMETER (CM-3600d, Japan).

As shown in Fig. 1, the conventional polarizing plate (Comparative Example 1) was a polarizing plate in which a film was used as a polarizer and bonded with an adhesive, and it was confirmed that the bent portion was not uniform when the polarizing plate was bent.

On the other hand, in the case of the polarizing plate (Example 1) according to the present invention, the polarizing plate is coated without using a film so that the curved portion is uniformly maintained at 1 to 10 mm (0.5 to 5 R) It was confirmed that the thickness of the polarizing plate was thinner.

Claims (14)

An isotropic film layer; A polarizer layer in which a lyotropic liquid crystal is coated on one surface of the isotropic film layer; And a retardation layer formed by coating a non-coated surface of the polarizer layer with a reactive liquid crystal compound
Polarizer. The method according to claim 1,
Wherein the isotropic film is a triacetate cellulose (TAC) film
Polarizer. The method according to claim 1,
Wherein the lyotropic liquid crystal is an aqueous lyotropic liquid crystal
Polarizer. The method according to claim 1,
Wherein the reactive liquid crystal compound is a non-aqueous reactive liquid crystal compound
Polarizer. The method according to claim 1,
Wherein the reactive liquid crystal compound is a reactive mesogen.
Polarizer. The method according to claim 1,
Wherein the retardation layer comprises a first retardation layer and a second retardation layer having an optical axis of 90 DEG and at least one of the first retardation layer and the second retardation layer is formed by coating a reactive liquid crystal compound ≪ / RTI >
Polarizer. The method according to claim 1,
Wherein the polarizing plate is characterized in that a hard coating layer is formed on the other surface of the isotropic film layer
Polarizer. The method according to claim 1,
Wherein the polarizing plate has a pressure-sensitive adhesive layer formed on an uncoated surface of the retardation layer
Polarizer. a) coating and drying a water-based lyotropic liquid crystal on one surface of an isotropic film to form a polarizer layer; And b) coating and drying an organic solvent-based reactive liquid crystal compound on the uncoated side of the polarizer layer to form a retardation layer
A method for producing a polarizing plate. 10. The method of claim 9,
Wherein the coating of step a) is a slot die coating or a spin coating.
A method for producing a polarizing plate. 10. The method of claim 9,
Drying in the step a) is conducted by electro-thermal drying by a conveying belt, a conveying rail or a conveying roller.
A method for producing a polarizing plate. 10. The method of claim 9,
Wherein drying in step a) is carried out at 50 to 80 캜
A method for producing a polarizing plate. 10. The method of claim 9,
Wherein the water-based lyotropic liquid crystal has a viscosity at 25 DEG C of 20 to 100 cps
A method for producing a polarizing plate. A polarizing plate comprising the polarizing plate of any one of claims 1 to 8
Display device.

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