KR101459127B1 - Polarizer plate and optical display device comprising the same - Google Patents

Abstract

 The present invention relates to a polarizing plate and an optical display device including the same. More specifically, the present invention provides a polarizing plate exhibiting a side color correcting effect and a frontal colorless effect, and an optical display device including the same.

Description

[0001] The present invention relates to a polarizing plate and an optical display device including the polarizing plate,

The present invention relates to a polarizing plate and an optical display device including the same. More specifically, the present invention provides a polarizing plate exhibiting a side color correcting effect and a frontal colorless effect, and an optical display device including the same.

An organic light emitting diode (OLED) display device is a self-emission type display device that electrically excites a fluorescent organic compound to emit light. Such a display device can be driven at a low voltage and has advantages such as thinness. In addition, the liquid crystal display device has attracted attention recently because it can solve the drawbacks pointed out as a problem in a liquid crystal display device such as a wide viewing angle and a fast response speed.

The organic light emitting diode display device generally includes a glass substrate, an organic electroluminescent portion formed on the glass substrate, a protective cap covering and protecting the organic electroluminescent portion, a moisture absorbent provided on the protective cap, And a polarizing plate. The polarizer is attached to the glass substrate surface to reduce the reflection of the glass by external light.

In an organic light emitting diode (OLED) display device, a white angular dependency (WAD) phenomenon caused by a side angle change may be a problem. WAD is a phenomenon in which whites appear on the front surface while blue appears on the side of the organic electroluminescent portion of the OLED. This is because the wavelength changes due to the change of the interference length due to the resonance structure when the organic electroluminescent unit emits light.

Up to now, various attempts have been made to solve the phenomenon of white light wavelength shift due to the variation of the side angle of the OLED, such as a polarizer, a phase difference dual type, a band cut type, and a biaxially stretched phase difference compensation. However, according to this, the effect of eliminating the white light wavelength shift phenomenon due to the side angle change is weak, and there is a problem that the thickness of the polarizing plate becomes thick.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polarizing plate capable of eliminating the phenomenon of white light wavelength shift due to a change in side angle.

Another object of the present invention is to provide a polarizing plate having a thin thickness while eliminating the phenomenon of white light wavelength shift due to a change in side angle.

It is still another object of the present invention to provide an optical display device including the polarizing plate.

The polarizing plate which is one aspect of the present invention comprises a polarizer, a protective film laminated on one surface of the polarizer, and a pressure-sensitive adhesive layer laminated on the other surface of the polarizer, wherein a liquid crystal layer containing a dye may be interposed between the polarizer and the pressure- have.

In one embodiment, a retardation film may be further included between the polarizer and the pressure-sensitive adhesive layer.

In one embodiment, a protective film and a retardation film may be further included between the polarizer and the pressure-sensitive adhesive layer.

In one embodiment, the dye-containing liquid crystal layer may comprise a cured product of a mixture of a dye and a liquid crystal.

In one embodiment, the dye has an absorption wavelength 380nm-780nm.

In one embodiment, the dye is selected from the group consisting of methine, azo, acridine, anthraquinone, diarylmethane, quinoline, azomethine, oxadiene, styryl, coumarin, porphyrin, dibenzofuranone Or a mixture thereof.

An optical display device which is another aspect of the present invention may include the polarizing plate.

The present invention provides a polarizing plate capable of eliminating the phenomenon of white light wavelength shift due to a change in side angle. The present invention provides a polarizing plate having a thin thickness as a single retardation film while eliminating the phenomenon of white light wavelength shift due to a change in side angle. The present invention provides an optical display device including the polarizing plate.

1 is a cross-sectional view of a polarizing plate according to one embodiment of the present invention.
Fig. 2 shows a cross-sectional view of a polarizing plate of another embodiment of the present invention.
3 shows a cross-sectional view of a polarizing plate of another embodiment of the present invention.
1: polarizer, 2a, 2b: protective film, 3: retardation film, 4: liquid crystal layer including dye,
5: surface treatment layer, 6: pressure-sensitive adhesive layer

The polarizing plate which is one aspect of the present invention comprises a polarizer, a protective film laminated on one surface of the polarizer, and a pressure-sensitive adhesive layer laminated on the other surface of the polarizer, wherein a liquid crystal layer containing a dye may be interposed between the polarizer and the pressure- have.

The dye-containing liquid crystal layer includes a cured product of a mixture of a dye and a liquid crystal.

The dye is a dye having an absorption wavelength of the yellow series, for example, a dye having an absorption wavelength of 380 to 780 nm, preferably 400 to 600 nm, more preferably 435 to 480 nm.

Specifically, the dyes may be selected from the group consisting of methine, azo, acridine, anthraquinone, diarylmethane, quinoline, azomethine, oxadiene, styryl, coumarin, porphyrin, dibenzofuranone, , But is not limited thereto.

The liquid crystal may be a UV curable reactive liquid crystal. The UV curable reactive liquid crystal contains reactive sites within the molecule which can cause a curing reaction upon irradiation with UV, for example, 500 mJ / m2 to 2000 mJ / m2. Therefore, a dye-containing liquid crystal layer can be formed by performing a curing reaction with a dye by UV irradiation. Further, the UV curable reactive liquid crystal is oriented in a C-plate shape by UV irradiation, for example, at 500 mJ / m2 to 2000 mJ / m2 irradiation. As the liquid crystal is oriented in the C-plate shape, the dye is also oriented in the same direction as the liquid crystal, and the side color correction effect can be obtained.

A commercially available liquid crystal can be purchased and used. For example, RMS03-015 from MERCK can be used, but is not limited thereto.

The content ratio of the dye and the liquid crystal in the dye-containing liquid crystal layer is not particularly limited, but the liquid crystal: dye may be contained in a weight ratio of 0.5: 1 to 20: 1. In the above range, sufficient side color correcting effect and front colorless effect can be obtained when the polarizing plate is laminated. Preferably from 1: 1 to 5: 1, more preferably from 2: 1 to 3: 1.

In the state before the mixture of the dye and the liquid crystal is cured, the dye and the liquid crystal are oriented in an arbitrary direction or shape. As a result, when the light is transmitted through the side of the polarizing plate, the dye can not sufficiently exhibit the absorption wavelength of the yellow series, and thus can not exhibit the side color correction effect with respect to the blue wavelength expressed on the side of the polarizing plate. However, after the mixture of the dye and the liquid crystal is cured, the liquid crystal is oriented in the C-plate shape and the dye is oriented in the same direction as the liquid crystal direction according to the orientation of the liquid crystal.

As a result, it has an effect of color-correcting a blue wavelength (side color correcting effect) expressed in the lateral direction of the polarizing plate by emitting a yellow-based wavelength when transmitting light in the lateral direction of the polarizing plate. On the other hand, when light is transmitted in the front direction of the polarizing plate, the dye may be oriented in the same direction as the liquid crystal direction, and thus the color may not be expressed on the front side (frontal colorless effect).

As used herein, the term "side" or "side angle" may refer to a range of -80 degrees to 80 degrees, preferably 10 degrees to 80 degrees or -80 degrees to-10 degrees, relative to a line perpendicular to the thickness direction of the polarizer have.

The dye-containing liquid crystal layer can be prepared by UV-curing a mixture of a dye and a liquid crystal under ordinary conditions. For example, a dye and a liquid crystal are mixed. In addition, methyl ethyl ketone, xylene or a mixture thereof may be contained as a solvent. A dye, a liquid crystal and optionally a solvent. The mixture is coated on a retardation film, a polarizer or a protective film. The solvent-containing liquid crystal layer can be prepared by evaporating the solvent and curing by irradiation with UV light. The UV irradiation conditions are not limited, but can be performed under the conditions of 500 mJ / m2-2000 mJ / m2 and 30 seconds to 10 minutes.

The dye-containing liquid crystal layer may have a thickness of 500 nm or less. In the above range, sufficient lateral color correction effect can be obtained when the polarizing plate is included. Preferably, the thickness is 100 nm to 500 nm, more preferably 100 nm to 400 nm.

The polarizing plate of the present invention may include a polarizer, a protective film laminated on one surface of the polarizer, and a pressure sensitive adhesive layer laminated on the other surface of the polarizer, and may include a liquid crystal layer including a dye between the polarizer and the pressure sensitive adhesive layer.

The polarizing plate may further include a retardation film between the polarizer and the pressure-sensitive adhesive layer.

1 shows a polarizer according to an embodiment of the present invention. 1, the polarizing plate includes a polarizer 1, a protective film 2a laminated on one side of the polarizer, and a pressure-sensitive adhesive layer 6 laminated on the other side of the polarizer. The retardation film 3 is formed on the polarizer, and the dye-containing liquid crystal layer 4 is formed on the pressure-sensitive adhesive layer. The protective film may further include a surface treatment layer 5 such as an antireflection layer, an antiglare layer, an antiglare layer, a antireflection composite layer, a hard coating layer, and the like.

2 shows a polarizer according to another embodiment of the present invention. 2, the polarizing plate includes a polarizer 1, a protective film 2a laminated on one surface of the polarizer, and a pressure-sensitive adhesive layer 6 laminated on the other surface of the polarizer. The dye-containing liquid crystal layer 4 is formed on the polarizer, and the retardation film 3 is formed on the pressure-sensitive adhesive layer. The protective film may further include a surface treatment layer 5 such as an antireflection layer, an antiglare layer, an antiglare layer, a antireflection composite layer, a hard coating layer, and the like.

The polarizing plate of the present invention may further include a protective film and a retardation film between the polarizer and the liquid crystal layer including the dye.

3 shows a polarizer according to another embodiment of the present invention. 3, the first protective film 2a is laminated on one surface of the polarizer 1, the second protective film 2b is laminated on the other surface of the polarizer, and the retardation film 3 is formed on the second protective film The dye-containing liquid crystal layer 4 is laminated on the retardation film, and the pressure-sensitive adhesive layer 6 is laminated on the dye-containing liquid crystal layer. The protective film 2a may further include a surface treatment layer 5 such as an antireflection layer, an antiglare layer, an antiglare layer, a antireflection composite layer, and a hard coating layer.

The polarizer aligns the direction of the light passing through the retardation film and divides the incident light into two polarizing components orthogonal to each other, passing only one component and absorbing or dispersing the other component.

The polarizer can be used without limitation as long as it is a polarizer commonly used in the production of a polarizing plate. Polarizers are prepared by dyeing a polyvinyl alcohol film with iodine or a dichroic dye and stretching it in a certain direction. Specifically, it is produced through a swelling process, a dyeing step, a stretching step and a crosslinking step. Methods of performing each step are commonly known to those skilled in the art.

The thickness of the polarizer is not particularly limited, but may preferably be 20 占 퐉 to 100 占 퐉.

The method of laminating the protective film on the polarizer is not particularly limited. For example, the protective film can be laminated to the polarizer through an adhesive layer. As the adhesive layer, a common adhesive such as an aqueous adhesive or a pressure-sensitive adhesive can be used.

The protective film may have a thickness of 20 占 퐉 to 1,000 占 퐉. In the above range, it can be used as a polarizing plate upon lamination to a polarizer. And preferably 30 占 퐉 to 200 占 퐉.

The protective film is not particularly limited, but examples thereof include cellulose-based, polyester-based, cyclic polyolefin-based, polycarbonate-based, polyether sulfone-based, polysulfone-based, polyamide-based, polyimide-based, polyolefin-based, polyarylate- A film made of a material selected from the group consisting of an alcohol type, a polyvinyl chloride type, a polyvinylidene chloride type, and a mixture thereof. Preferably, cellulose-based, more preferably triacetylcellulose (TAC) films can be used.

The pressure-sensitive adhesive layer is a conventional adhesive for laminating the polarizing plate to the organic light-emitting diode, and acrylic resin or the like can be used, but the present invention is not limited thereto.

The retardation film can adjust the optical characteristics of the light to adjust the phase difference or to improve the viewing angle. The retardation film is a lambda / 4 retardation film. It serves to change the linear polarization to circular polarized light or to convert circular polarized light to linear polarized light by providing a phase difference of? / 4 to two mutually perpendicular polarization components parallel to the optical axis of the retardation film do. The retardation film changes the light resistance of the organic light emitting diode display device from circularly polarized light to linearly polarized light or changes linearly polarized light from linearly incoming light from the outside.

The retardation film may be a film having a front retardation (R ₀ ) value of 0-200 nm.

The retardation film is usually used in a polarizing plate, and any film having a retardation function can be used without limitation. As the retardation film, a film made of cycloolefin polymer (COP), acrylic, cellulose, olefin or a mixture thereof can be used. Preferably, a cycloolefin polymer film can be used.

The thickness of the retardation film may be 10 占 퐉 to 100 占 퐉. In this range, it is possible to provide an optical compensation effect when used in a polarizing plate, and can have a circular polarization effect. And preferably 10 占 퐉 to 60 占 퐉 thickness.

In the polarizing plate of the present invention, the protective film may be a surface-treated protective film. The surface treatment is intended to impart functionality to the protective film and may include, for example, antireflection treatment, antiglare treatment, antireflection and antireflection composite treatment, hard coating treatment and the like.

An optical display device which is another aspect of the present invention may include the polarizing plate. The optical display device may include, but is not limited to, an organic light emitting diode display device.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Specific specifications of the components used in the following examples and comparative examples are as follows.

(1) A polyvinyl alcohol film (PS60, Kuraray Co., Ltd., thickness 60 占 퐉) was used as the material of the polarizer.

(2) A triacetyl cellulose film (N-TAC, Konica Corp., thickness 40 占 퐉) was used as a protective film.

(3) As a retardation film, a cyclic olefin polymer film (ZEONOR, Japan ZEON Co., thickness: 33 탆) was used.

(4) Dyeing The liquid crystal layer (RMS03-015, manufactured by MERCK) was used as a material for the liquid crystal layer, such as a dye (PF2, methine series, Gyeongin Ink, absorption wavelength = 435 to 480 nm).

Example  One

Polarizers were prepared by subjecting the material of the polarizer to a process such as dyeing and drawing. Specifically, the polyvinyl alcohol film was stretched twice at 50 ° C, adsorbed iodine, and then stretched 2.5 times in an aqueous boric acid solution at 40 ° C to prepare a polarizer. A retardation film was bonded to one surface of the polarizer using an adhesive. The protective film was bonded to the other surface of the polarizer using an adhesive. A mixed solvent of xylene and methyl ethyl ketone was added to a mixture of 1 part by weight of liquid crystal and 0.5 part by weight of dye (liquid crystal: dye ratio by weight = 2: 1) to prepare 5 parts by weight of a mixture for forming a liquid crystal layer containing a dye. The mixture was uniformly coated on one side of the retardation film, and the solvent was evaporated. 1200 mJ / m < 2 > for 60 seconds to irradiate UV light to laminate a dye-containing liquid crystal layer (thickness: 400 nm) on the retardation film. A pressure sensitive adhesive layer was laminated on the liquid crystal layer including the dye to prepare a polarizing plate.

Example  2

A polarizer was prepared in the same manner as in Example 1 above. A protective film was bonded to both sides of the polarizer using an adhesive. A retardation film was laminated using an adhesive to one of the protective films. A mixed solvent of xylene and methyl ethyl ketone was added to a mixture of 0.9 part by weight of liquid crystal and 0.3 part by weight of dye (liquid crystal: dye ratio = 3: 1) to prepare 5 parts by weight of a mixture for forming a liquid crystal layer containing a dye. The mixture was uniformly coated on one side of the retardation film, and the solvent was evaporated. 1200 mJ / m < 2 > for 60 seconds to irradiate UV light to laminate a dye-containing liquid crystal layer (thickness: 400 nm) on the retardation film. A pressure sensitive adhesive layer was laminated on the liquid crystal layer including the dye to prepare a polarizing plate.

Example  3-4

A polarizing plate was produced in the same manner as in Example 1 except that the thickness of the dye-containing liquid crystal layer was changed as shown in Table 1 below.

Comparative Example  One

A polarizing plate was produced in the same manner as in Example 1 except that a liquid crystal layer containing a dye was not formed on the retardation film.

Comparative Example  2

Except that a solution containing 0.5 parts by weight of a dye and 4.5 parts by weight of a mixed solvent of xylene and methyl ethyl ketone was used instead of the mixture for forming a dye-containing liquid crystal layer in Example 1 to prepare a polarizing plate Respectively.

Experimental Example : Measurement of physical properties of polarizer

Organic light emitting diodes were assembled using the polarizing plates prepared in the above Examples and Comparative Examples, and the following properties were evaluated. The results are shown in Table 1 below.

(1) Side color correction effect: After attaching the polarizing plate to the organic light emitting diode panel, the absorption rate of the yellow wavelength band (wavelength = 435 to 480 nm) was measured at an angle of 60 degrees with an ultraviolet-visible spectrophotometer. ⊚ when the water absorption rate is 10% or more, ∘ when the water absorption rate is less than 10% ? When the water absorption rate was less than 1% and less than 5%, and? When the water absorption rate was less than 1%.

(2) Front colorless effect: A polarizing plate was attached to an organic light emitting diode panel, and the absorption rate was 0% when the absorption rate at the yellow wavelength band (wavelength = 435 to 480 nm) was 0% at 0 degree angle with the ultraviolet-visible spectrophotometer 5% or less,? When the water absorption rate is more than 5% and less than 10%,? And when the water absorption rate was 10% or more, the evaluation was X. [

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Presence of liquid crystal layer including dye ○ ○ ○ ○ × × Thickness of liquid crystal layer including dye (nm) 400 400 200 100 - - Presence or absence of dye layer × × × × × ○ Thickness of dye layer (nm) - - - - - 100 Side color correction effect ◎ ○ △ △ × ◎ Front colorless effect ◎ ○ △ △ ◎ ×

As shown in Table 1, the polarizing plate of the present invention has a lateral color compensation effect for color-correcting a blue wavelength emitted from a side when light is transmitted through a side surface, but does not exhibit a color at the front. On the other hand, when the liquid crystal layer including the dye was not included, the side color correction effect was not obtained, and the polarizing plate including only the dye layer had a high side color correction effect but no front colorless effect.

Claims (15)

Polarizers,
A protective film laminated on one surface of the polarizer, and
And a pressure-sensitive adhesive layer laminated on the other surface of the polarizer,
And a dye-containing liquid crystal layer between the polarizer and the pressure-sensitive adhesive layer,
Wherein the dye in the dye-containing liquid crystal layer has an absorption wavelength of 400-600 nm. The polarizer of claim 1, further comprising a retardation film between the polarizer and the pressure-sensitive adhesive layer. The film according to claim 2, wherein the retardation film Wherein the dye-containing liquid crystal layer is laminated on the polarizer, and the dye-containing liquid crystal layer is laminated on the pressure-sensitive adhesive layer. The polarizing plate according to claim 2, wherein the dye-containing liquid crystal layer is laminated on the polarizer, and the retardation film is laminated on the pressure-sensitive adhesive layer. The polarizer of claim 1, further comprising a protective film and a retardation film between the polarizer and the pressure-sensitive adhesive layer. The liquid crystal display device according to claim 5, wherein the polarizing plate comprises: a protective film laminated on one surface of the polarizer; a protective film and a retardation film sequentially laminated on the other surface of the polarizer; And the pressure-sensitive adhesive layer is laminated on the dye-containing liquid crystal layer. The polarizing plate for organic light emitting diode display according to claim 1, wherein the protective film is surface-treated. The polarizing plate for an organic light emitting diode display according to claim 7, wherein the surface treatment includes at least one selected from the group consisting of anti-reflection treatment, hard coating treatment and anti-glare treatment. The polarizing plate for organic light emitting diode display according to claim 1, wherein the dye-containing liquid crystal layer has a thickness of 500 nm or less. The polarizing plate for organic light emitting diode display according to claim 1, wherein the dye-containing liquid crystal layer is a cured product of the dye and the liquid crystal mixture. 11. The polarizing plate for an organic light emitting diode display according to claim 10, wherein the liquid crystal is oriented in a C-plate shape upon UV irradiation. delete 11. The method of claim 10, wherein the dye is selected from the group consisting of methine, azo, acridine, anthraquinone, diarylmethane, quinoline, azomethine, oxadiene, styryl, coumarin, porphyrin, And mixtures thereof. ≪ RTI ID = 0.0 > 11. < / RTI > The polarizer of claim 10, wherein the liquid crystal and the dye are contained in a weight ratio of liquid crystal: dye = 0.5: 1 to 20: 1. An organic light emitting diode display device comprising the polarizing plate for the organic light emitting diode display according to any one of claims 1 to 11 and 13 to 14.

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