KR20180098789A - Polarizing plate and display device comprising the same - Google Patents

Abstract

According to the present invention, a polarizing plate comprises: a polarizer; a first protective member provided on one surface of the polarizer; a second protective member provided on the other surface of the polarizer; and an adhesive layer provided on an upper surface of the first protective member or on an upper surface of the second protective member, which is not in contact with the polarizer. At least one among the first protective member, the second protective member, and the adhesive layer includes a first dye having a center absorption wavelength (λmax) of 470 to 510 nm. However, all of the first protective member, the second protective member and the adhesive layer do not include the first dye, and at least one of the first protective member, the second protective member and the adhesive layer not including the first dye includes a second dye having a center absorption wavelength (λmax) of 580 to 600 nm. The polarizing plate according to the present invention does not cause discoloration and a bleed-out phenomenon even when exposed to a high temperature and high humidity environment for a long period of time, and an image display device including the polarizing plate according to the present invention has excellent effects of visibility, color purity, and the like.

Description

TECHNICAL FIELD [0001] The present invention relates to a polarizing plate and an image display device including the polarizing plate.

The present invention relates to a polarizing plate and an image display apparatus including the same.

The polarizing plate is useful as one of optical members constituting an image display device such as a liquid crystal display. The polarizing plate usually has a structure in which a protective film is laminated on both surfaces of a polarizer and has a structure in which an adhesive layer is formed on one surface for attachment to a liquid crystal cell containing liquid crystal or the like.

 In an image display device such as a liquid crystal display, a specific spectrum of a light source is cut by a color filter to obtain a color image, so that color purity may be influenced by characteristics of various components such as a polarizing plate.

Korean Patent Laid-Open Publication No. 2014-0079216 relates to a polarizing film and an organic light emitting device comprising the polarizing film, wherein the polarizing film includes a coating layer, a linear polarizer, a circular polarizing layer and a pressure-sensitive adhesive layer, And at least one dye having at least one absorption wavelength selected from the group consisting of a dye and a dye.

However, in the above-mentioned literature, there is a problem of discoloration upon exposure to a high-temperature and high-humidity environment, and a bleed-out phenomenon of the dye occurs, thereby deteriorating visibility and color purity.

Therefore, development of a polarizing plate that does not deteriorate visibility and color purity even when exposed to a high temperature and high humidity environment for a long time is required.

Korea Patent Publication No. 2014-0079216 (June 26, 2014)

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a polarizing plate which does not cause discoloration and bleed-out phenomenon even when exposed to a high temperature and high humidity environment for a long time.

The present invention also provides an image display device with improved visibility and color purity.

According to an aspect of the present invention, there is provided a polarizer comprising: a polarizer; A first protective substrate provided on one surface of the polarizer; A second protective substrate provided on the other surface of the polarizer; And a pressure-sensitive adhesive layer provided on the upper surface of the first protective substrate or on the upper surface of the second protective substrate that is not in contact with the polarizer, and at least one of the first protective substrate, the second protective substrate, a center absorption wavelength (λ _max) 470 to include, and only the first dye of 510nm, the first protective substrate, wherein the second protective substrate and not all of the pressure-sensitive adhesive layer containing the first dye, the first At least one of the first protective substrate, the second protective substrate, and the pressure-sensitive adhesive layer not containing a dye includes a second dye having a center absorption wavelength (? _Max ) of 580 to 600 nm.

Further, the image display apparatus according to the present invention is characterized by including the above-mentioned polarizing plate.

The polarizing plate according to the present invention is advantageous in that discoloration and bleed-out phenomenon do not occur even when exposed to a high temperature and high humidity environment for a long time.

Further, since the image display apparatus according to the present invention includes a polarizing plate that absorbs a specific wavelength, it has an advantage of excellent visibility and color purity.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram illustrating the structure of a polarizing plate according to some embodiments of the present invention. Fig.

Hereinafter, the present invention will be described in more detail.

When a member is referred to as being " on "another member in the present invention, this includes not only when a member is in contact with another member but also when another member exists between the two members.

Whenever a part is referred to as "including " an element in the present invention, it is to be understood that it may include other elements as well, without departing from the other elements unless specifically stated otherwise.

<Polarizer>

One aspect of the present invention relates to a polarizer (10); A first protective substrate 20 provided on one surface of the polarizer 10; A second protective substrate 30 provided on the other surface of the polarizer 10; And a pressure sensitive adhesive layer (40) provided on an upper surface of the first protective substrate (20) not in contact with the polarizer (10) or an upper surface of the second protective substrate (30) Wherein at least one of the second protective substrate 30 and the pressure sensitive adhesive layer 40 comprises a first dye having a center absorption wavelength λ _max of 470 to 510 nm, , The second protective substrate (30) and the pressure sensitive adhesive layer (40) do not include the first dye, and the first protective substrate, the second protective substrate (30) and the second protective substrate At least one of the pressure-sensitive adhesive layer (40) is a polarizing plate (100) comprising a second dye having a center absorption wavelength (? _Max ) of 580 to 600 nm.

In other words, the polarizing plate 100 according to the present invention is characterized in that at least one of the first protective substrate 20, the second protective substrate 30 and the pressure-sensitive adhesive layer 40 comprises the first dye, The first protective substrate 20, the second protective substrate 30, and the pressure sensitive adhesive layer 40 are not limited to the first protective layer 20, the second protective layer 30, And the second dye in the pressure-sensitive adhesive layer (40), at least one of the structures not including the first dye.

In one embodiment of the invention, the first dye is an anthraquinone, methine of 470 to 510nm center absorption wavelength (λ _max), azomethine-based, oxazole dingye, azo, styryl rilgye, coumarin, porphyrin , A dibenzofuranone dye, a diketopyrrolopyrrole dye, a rhodamine dye, a cholic acid dye, and a pyrrole dye dye.

The photopolymerization initiator is preferably selected from the group consisting of anthraquinone, methine, azomethine, oxazine, azo, styryl, coumarin, porphyrin, dibenzofuranol, diketopyrrolopyrrol, rhodamine, And pyrrole-based dyes are excellent in durability. Therefore, when used as the first dye, discoloration and bleed-out phenomenon do not occur even when exposed to a high temperature and high humidity environment for a long time.

The first dye includes, for example, oxazine-170, indolo [2,1-b] [1,3] benzoxazine (indolo [2,1-b] 1,3] benzoxazine) can be used. As the azo dye, p-phenylazoaniline can be used. Rhodamine 6G (Rhodamine 6G, R6G) can be used as the rhodamine dye, Coumarin 6 (C6) can be used as the coumarin-based dye, and 5- (1- (4-carboxybutyl) pyridinium-4-yl) 10,10,20-tris 1-methylpyridinium-4-yl) porphyrin.

Specifically, the first dye may be an anthraquinone dye represented by the following formula (1).

[Chemical Formula 1]

In a further embodiment of the invention, the second dye is a center absorption wavelength (λ _max) porphyrin series of 580 to 600nm, quinophthalone-based, tea oak acid tingye, methine-based, Perry nongye, anthrapyridone dongye and quinazoline And at least one dye selected from the group consisting of red, green, and blue dye.

In the case of the dyes excellent in durability in the case of the papyrin type, quinophthalone type, thioxanthin type, methine type, perinone type, anthrapyridone type and quinacridone type dyes having a central absorption wavelength (λ _max ) of 580 to 600 nm, There is an advantage that discoloration and a bleed-out phenomenon do not occur even when exposed for a long time.

As the second dye, for example, disazo perinone may be used as the perionone dye, and di (methylsulphonyl) quinacridone may be used as the quinacridone dye, It is not limited.

Specifically, the second dye may be a porphyrin dye represented by the following formula (2).

(2)

In Formula 2,

X is nitrogen or carbon,

R 1 to R 3 are each independently hydrogen; Or an alkyl, allyl, aromatic or hetero ring having 1 to 20 carbon atoms,

However, when X is nitrogen, R3 is not present.

The first dye according to the present invention selectively absorbs light of 470 to 510 nm, and the second dye selectively absorbs light of 580 to 600 nm.

Therefore, the polarizing plate 100 according to the present invention has an advantage of being excellent in visibility and color purity when applied to an image display device by including the first dye and the second dye.

The first dye is used in an amount of 5 to 30 parts by weight per 100 parts by weight of the total of the first protective substrate 20, the second protective substrate 30 and the pressure-sensitive adhesive layer 40 including the first dye, 5 to 20 parts by weight, more preferably 5 to 10 parts by weight. For example, when the second protective substrate 30 includes the first dye, the first dye may be included within the above range with respect to 100 parts by weight of the second protective substrate 30 as a whole.

The second dye is used in an amount of 5 to 30 parts by weight per 100 parts by weight of the total of the first protective substrate 20, the second protective substrate 30 and the pressure-sensitive adhesive layer 40 including the second dye, 5 to 20 parts by weight, more preferably 5 to 10 parts by weight. For example, when the second protective substrate 30 includes the second dye, the second dye may be included within the above range for 100 parts by weight of the entire second protective substrate 30.

When the first and second dyes are contained within the above ranges, the polarizer 100 having excellent durability and improved visibility and color purity when applied to an image display apparatus can be advantageously manufactured.

The first protective substrate 20 and the second protective substrate 30 are preferably made of a material selected from the group consisting of polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polytetrafluoroethylene, polybutylene terephthalate, polybutylene terephthalate, Polyester-based resins such as butylene 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-based resin, and the like.

The thermoplastic resin may serve as a binder for the first protective substrate 20 and the second protective substrate 30, and may include, but not limited to, a blend of the thermoplastic resin.

Further, it may include, but is not limited to, a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, or silicone, or a UV curable resin.

The content of the resin is 50 to 100 parts by weight, preferably 50 to 99 parts by weight, and more preferably 60 to 100 parts by weight, based on 100 parts by weight of the total of each of the first protective substrate 20 and the second protective substrate 30 To 98 parts by weight, and most preferably 70 to 97 parts by weight. When the content of the resin is within the above range, there is an advantage that high durability and high transparency can be exhibited.

The first protective substrate 20 and the second protective substrate 30 may be coated with an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a releasing agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent , And the content of the additive is not particularly limited.

The pressure-sensitive adhesive layer 40 may include acrylic, silicone, polyester, fluorine-based, or rubber-based resins as a layer for bonding with a liquid crystal cell or the like, but is not limited thereto. The pressure-sensitive adhesive layer (40) is excellent in the moldability of an image display device which is superior in quality and durability such as prevention of peeling phenomenon due to moisture absorption, bubble generation phenomenon, warping of a liquid crystal cell due to difference between thermal expansion coefficients, It is preferable that the moisture absorption rate is low and the heat resistance is excellent. Further, in consideration of optical characteristics, it is preferable that any high-temperature treatment such as curing or drying is not required, or that long-term curing or drying is not required. From this viewpoint, it is preferable to include an acrylic resin.

The thickness of the pressure-sensitive adhesive layer 40 may be suitably determined according to the purpose of use and the re-peelability, and may be usually 1 to 500 μm, preferably 5 to 200 μm, more preferably 10 to 100 μm have.

The method of manufacturing the first protective substrate 20, the second protective substrate 30, and the pressure-sensitive adhesive layer 40 is not limited to the present invention, and may be manufactured by a conventional method used in the art.

For example, each of the protective substrates, i.e., the first protective substrate 20 and the second protective substrate 30, can be generally manufactured by the same method as the conventional TAC manufacturing method, and a predetermined amount of a dye and a DDDMAB (Didodecyldimethyl ammonium bromide) After dissolving in THF (Tetrahydrofuran) and mixing with the protective substrate, a film can be formed. The formed protective substrate is bonded to the polarizer 10 using an adhesive, but is not limited thereto.

1, a polarizing plate 100 according to the present invention includes a first protective substrate 20 on one side of a polarizer 10 and a second protective substrate 30 and an adhesive layer 40 on the other side But the present invention is not limited thereto.

The first protective substrate 20 or the second protective substrate 30 may have a function as a retardation film. Specifically, the first protective substrate 20 or the second protective substrate 30 which is in contact with the pressure-sensitive adhesive layer 40 may have a function as a retardation film.

More specifically, the polarizer 10, the second protective substrate 30 and the pressure-sensitive adhesive layer 40 may be sequentially laminated on the lower surface of the first protective substrate 20, The second protective substrate 30 may have a function as a retardation film.

Specifically, in the present invention, the structure of the polarizing plate 100 is not particularly limited, and various kinds of optical layers capable of satisfying the required optical characteristics within the range of not hindering the object of the present invention may be used as the polarizer 10, Or the like. For example, the polarizing plate 100 may be formed by laminating a surface treatment layer such as a hard coating layer, an antireflection layer, an anti-adhesion layer, a diffusion preventing layer and an antiglare layer, or by laminating at least one surface of the polarizer 10 or the first protective substrate 20 and / 2 alignment liquid crystal layer for compensating the viewing angle on the protective substrate 30 or another functional film stacked thereon. Further, it is also possible to use an optical film such as a polarization conversion device used for forming various image display devices, a retardation film including a wave plate (including? Plate) such as a reflector, a transflector plate, a half- A plate, a viewing angle compensating film, and a luminance improving film may be laminated with an optical layer. More specifically, a reflective polarizing plate 100 or a transflective polarizing plate 100 in which a reflector or a transflective reflector is laminated on the first protective substrate 20 and / or the second protective substrate 30 laminated, A wide viewing angle polarizing plate 100 in which a viewing angle compensating film or a viewing angle compensating film is laminated, or a polarizing plate 100 in which a brightness enhancing film is laminated, and the like are preferable.

In other words, the polarizer 100 may have a composition and composition commonly used in the art. In the present invention, a method of manufacturing the polarizer 10 and the like included in the polarizer 100 and the polarizer 100 is not limited Do not.

For example, the polarizer 10 has a dichroic dye adsorbed and oriented on the stretched polymer film. If the polymer film constituting the polarizer 10 is a film that can be dyed with a dichroic substance, such as iodine, the kind thereof is not particularly limited And specifically includes a hydrophilic polymer film such as a polyvinyl alcohol film, an ethylene-vinyl acetate copolymer film, an ethylene-vinyl alcohol copolymer film, a cellulose film, a partially saponified film thereof and the like; Or a dehydrated polyvinyl alcohol film, a dehydrochloric acid-treated polyvinyl alcohol film, and the like. Of these, a polyvinyl alcohol-based film is preferable because it has an excellent effect of enhancing the uniformity of the degree of polarization in the plane and is excellent in dye affinity for a dichroic substance.

Polarizing plate 100 in accordance with the present invention, the first protective substrate 20, the second protective substrate 30 and the first dye in the pressure-sensitive adhesive layer 40, at least one is a center absorption wavelength (λ _max) of 470 to 510nm , Wherein the first protective substrate (20), the second protective substrate (30) and the pressure sensitive adhesive layer (40) both do not contain the first dye, and the first protective substrate Since at least one of the first protective substrate, the second protective substrate 30 and the pressure-sensitive adhesive layer 40 includes the second dye having a center absorption wavelength (? _Max ) of 580 to 600 nm, the peak wavelength of the emission spectrum is 470 to 510 nm And the second spectrum of the peak wavelength of 580 to 600 nm, the point at which the blue and green peak wavelengths intersect with each other in the emission spectrum and the point at which the peak wavelengths of green and red cross each other are lower in intensity, When applied to an image display device, color purity and coloring This has the advantage of being improved.

<Image Display Device>

Another aspect of the present invention relates to an image display apparatus including the polarizing plate 100 described above.

Specific examples of the image display device include a liquid crystal display (LCD), an organic EL display (organic EL display), a liquid crystal projector, a display device for a game machine, a display device for a portable terminal such as a mobile phone, A display device such as a display device for car navigation, and the like, but is not limited thereto.

Since the image display device according to the present invention includes the first dye and the second dye excellent in durability and contained in the polarizer 100, it does not cause discoloration and bleed-out phenomenon even when exposed to a high temperature and high humidity for a long time, The first dye and the second dye absorb the specific wavelength, which is advantageous in terms of visibility and color purity.

Hereinafter, the present invention will be described in detail by way of examples to illustrate the present invention. However, the embodiments according to the present disclosure can be modified in various other forms, and the scope of the present specification is not construed as being limited to the above-described embodiments. Embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art. In the following, "%" and "part" representing the content are by weight unless otherwise specified.

Reference Example , Example  And Comparative Example

A first protective substrate and a second protective substrate are bonded to each other using an epoxy adhesive as an ultraviolet curing adhesive on a polyvinyl alcohol polarizer and a urethane acrylate adhesive is applied to the upper surface of the second protective substrate not in contact with the polarizer To form a pressure-sensitive adhesive layer to prepare a polarizing plate.

At this time, in the first protective substrate and the second protective substrate, the first dye and the second dye were applied to respective layers (the first protective substrate, the second protective substrate, and the second protective substrate) containing the first and second dyes, 2) and 5 parts by weight with respect to 100 parts by weight of the total of the first protective substrate and the second protective substrate. The first protective substrate and the second protective substrate contained a dye and a DDDMAB (Didodecyldimethyl ammonium bromide) dispersant according to the composition and composition shown in Table 1 in tetrahydrofuran Melted and mixed with each protective substrate.

The protective substrates (first protective substrate and second protective substrate) prepared according to Reference Examples, Examples and Comparative Examples and the pressure-sensitive adhesive layer, the transmittance and the light resistance of the polarizing plate were measured, and the results are shown in Table 1 below.

Remarks Item Reference Example Example Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 The first protective substrate Dyes of λ _max 470 to 510 nm - Anthraquinone dye ^{1 )} Anthraquinone dye ^{1 )} - Cyanine dyes ³⁾ - The second protective substrate λ _max Dyes of 580 to 600 nm - Porphyrin dyes ²⁾ - Porphyrin dyes ²⁾ - Squarylium-based dyes ^{4 )} Protective substrate, pressure-sensitive adhesive layer @ 476 nm
Transmittance (%) 92.12 13.24 13.21 92.34 13.78 92.41 Protective substrate, pressure-sensitive adhesive layer @ 593 nm
Transmittance (%) 92.77 10.21 92.54 10.24 92.99 12.11 Polarizer @ 476 nm
Transmittance (%) 44.42 6.11 6.12 44.44 6.42 44.48 Polarizer @ 593 nm
Transmittance (%) 44.54 4.65 44.52 4.78 44.47 7.84 Polarizer Light resistance ○ ○ ○ ○ × ×

1) An anthraquinone dye represented by the formula (1)

[Chemical Formula 1]

2) a porphyrin-based dye represented by the general formula (2)

(2)

(R1: hydrogen, R2: hydrogen, R3: hydrogen, X: carbon)

3) a cyanine dye represented by the general formula (3)

(3)

4) a squarylium-based dye represented by the general formula (4)

[Chemical Formula 4]

(R ¹ : methyl group, R ² : methyl group, R ³ : methyl group, R ⁴ : hydrogen, R ⁵ :

(1) Transmittance and unit transmittance

The transmittance (unit transmittance) was measured using UV-VIS Spectroscopy (V-710, Jasco), and the results are shown in Table 1 above. The UV-VIS spectroscopy used consists of a body, a light source, a sample stage, a computer body, and a monitor. The sample is attached to a holder with a hole in the center of a circle, After the measurement, the overall optical properties such as the basic transmittance, the parallel transmittance, the orthogonal transmittance, and the polarization degree of the polarizing plate were obtained.

At this time, the mass transmittance was calculated using the following equation (1).

[Equation 1]

(TY) = (TMD + TTD) / 2

(Where TMD is the average transmittance in the absorption axis direction and TTD is the average transmittance in the transmission axis direction).

(2) Light resistance

The light resistance of a polarizing plate including a pressure-sensitive adhesive layer was measured using a fade meter (U48AU manufactured by SUGA). The evaluation conditions were as shown in Table 1, after irradiating ultraviolet rays (388 nm) at 40 ° C / 50% RH for 48 hours. When there was no deterioration, it was indicated by o, within 10%, and when it exceeded 10%, it was indicated by x.

As can be seen from Table 1, the polarizing plate according to the example selectively absorbs light having a wavelength of 470 to 510 nm and 580 to 600 nm, and there is no light resistance problem. However, the polarizing plate according to the comparative example has a low absorption rate It can be seen that there is a problem in

10: Polarizer
20: First protective substrate
30: Second protective substrate
40: pressure-sensitive adhesive layer
100: polarizer

Claims (4)

A polarizer;
A first protective substrate provided on one surface of the polarizer;
A second protective substrate provided on the other surface of the polarizer; And
A pressure-sensitive adhesive layer provided on an upper surface of the first protective substrate that is not in contact with the polarizer or an upper surface of the second protective substrate;
/ RTI &gt;
Wherein at least one of the first protective substrate, the second protective substrate and the pressure sensitive adhesive layer comprises a first dye having a center absorption wavelength (λ _max ) of 470 to 510 nm, And wherein the pressure-sensitive adhesive layer does not include the first dye,
Wherein at least one of the first protective substrate, the second protective substrate and the pressure-sensitive adhesive layer not containing the first dye comprises a second dye having a center absorption wavelength (? _Max ) of 580 to 600 nm. The method according to claim 1,
The first dye may be an anthraquinone dye, a methine dye, an azomethine dye, an oxazine dye, an azo dye, a styryl dye, a coumarin dye, a porphyrin dye, a dibenzofuranone dye, a diketopyrrolopyrrol dye, a rhodamine dye, Wherein the polarizing plate comprises at least one selected from the group consisting of tungsten dyes. The method according to claim 1,
Wherein the second dye comprises at least one selected from the group consisting of porphyrin, quinophthalone, thioxanthine, methine, perinone, anthrapyridone and quinacridone dyes. An image display device comprising the polarizing plate according to any one of claims 1 to 3.

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