KR101932800B1

KR101932800B1 - Polarizing plate

Info

Publication number: KR101932800B1
Application number: KR1020150040835A
Authority: KR
Inventors: 김현석; 문정옥; 박형숙; 양세우; 유현지; 손현희; 최반석
Original assignee: 주식회사 엘지화학
Priority date: 2015-03-24
Filing date: 2015-03-24
Publication date: 2018-12-26
Also published as: KR20160114394A

Abstract

This application relates to a polarizing plate and a display device. The present application can provide a polarizing plate which can be applied to various types of display devices, particularly a display device including a high reflection liquid crystal panel, to improve the visual feeling in the dark state and to improve the contrast ratio. In the present application, a display device including the polarizer can also be provided.

Description

POLARIZING PLATE

This application relates to a polarizing plate.

LCD (Liquid Crystal Display) is a display device using light transmittance varying according to the arrangement of liquid crystals. It controls the transmission of light emitted from a backlight according to a voltage applied to the liquid crystal, passes through a color filter, can do.

In general, an LCD is a display in which a liquid crystal is positioned between a lower substrate on which a TFT (Thin Film Transistor) is formed and an upper substrate on which a color filter is formed, and an electric signal is transmitted to the TFT to control the liquid crystal. Is used.

The present application provides a polarizing plate. The present application is a polarizing plate that is applied to a display device such as an LCD (Liquid Crystal Display) to improve a visual feeling in a light blocking state (black state) and improve a contrast ratio (CR) To provide a polarizing plate which can exert excellent effects.

This application is directed to a polarizer. For example, the polarizer includes a polarizer; A transparent film attached to one surface of the polarizer by a first adhesive layer or an adhesive layer; And a second pressure-sensitive adhesive layer formed on a surface of the polarizer opposite to the surface on which the transparent film is adhered. The polarizing plate of the present application may have various structures based on the above structure. For example, in the above, the transparent film is a protective film for the polarizer, and this transparent protective film may further exist between the polarizer and the second pressure sensitive adhesive layer. In addition, an additional functional layer such as a high hardness layer or a low reflection layer may be present outside the transparent film. In addition to the elements, other elements such as a retardation film or a brightness enhancement film may be added to the polarizing plate.

The term polarizer and polarizer plate have different meanings in this specification. The term polarizer refers to, for example, a functional element exhibiting a polarizing function such as a poly (vinyl alcohol) (PVA) film, and the polarizing plate may include other elements such as the above-mentioned transparent film, Or an adhesive layer or the like.

The polarizing plate of the present application may be a polarizing plate for a highly reflective liquid crystal panel. The term high reflection liquid crystal panel in the present application may mean a liquid crystal panel having a reflectance of 12% or more, 14% or more, 16% or more, or 18% or more. In this case, the reflectance may be the reflectance for light of a wavelength of about 550 nm. The reflectance of the high reflection liquid crystal panel may be, for example, 30% or less, 28% or less, 26% or less, 24% or less, 22% or less or 20% or less.

Generally, a liquid crystal panel includes a liquid crystal interposed between an upper substrate and a lower substrate. A TFT (Thin Film Transistor) capable of applying an electrical signal is present on the lower substrate, and a color filter is generally present on the upper substrate. A so-called BM (Black Matrix) exists in the color filter. Thus, the liquid crystal panel in which BM exists usually exhibits a reflectance (about 550 nm wavelength) at a reflectance of about 10%.

The high reflection liquid crystal panel has a structure in which a BM having a characteristic of absorbing or blocking light is removed in comparison with the conventional structure as described above, a structure in which a color filter and BM exist together with a TFT on the lower substrate side A structure in which a BM is not present, a structure in which a color filter and a TFT are present together on a lower substrate side, and the like. In one example, the highly reflective liquid crystal panel may be a panel in which a color filter and a TFT are disposed together on a lower substrate, and in this case, the liquid crystal panel may or may not include the BM. The elevated reflectance of the high reflection liquid crystal panel may affect the color of the display device, especially the color of the black state. In the above, the term dark state is a state in which the liquid crystal panel is adjusted to block light from the light source, for example, a voltage off state in the normally black mode or a voltage on in the normal white mode State. &Lt; / RTI > Further, in the case of a panel not including the BM in the high reflection liquid crystal panel, a larger light leakage due to an increase in the aperture ratio or the like may be caused in the dark state, and such light leakage may cause the color feeling in the dark state to be approximately red or close to yellow can do. The polarizer of the present application has optical characteristics described later, and such optical characteristics can maximize its advantages while solving the problems that may occur in such a high reflection liquid crystal panel.

Accordingly, the high reflection liquid crystal panel to which the polarizing plate of the present application is applied may be a liquid crystal panel in which a color filter existing on the former upper substrate side exists together with the TFT on the lower substrate. The structure in which the color filter and the TFT are present on the lower substrate at the same time can be advantageous for realizing various structures such as a curved surface structure. In the above structure, the BM may or may not exist.

The polarizer may be an upper polarizer of the liquid crystal panel. In the present application, the term top refers to the direction from the display device to the observer observing the image in a state in which the display device implements the image, and the term lower part may mean the opposite direction. The upper polarizer plate may also be referred to as a viewer-side polarizer plate in another term. Further, the term lower polarizer (or polarizing plate) in the present application may also be referred to as a back-side polarizer (or a polarizing plate) or a light source-side polarizing plate (or a polarizing plate).

The pressure sensitive adhesive layer or adhesive layer included in the polarizing plate or the polarizing plate of the present application may have controlled optical characteristics. Unless specifically stated otherwise, the following physical properties may be physical properties of the polarizing plate itself or physical properties of the pressure-sensitive adhesive layer or the adhesive layer contained in the polarizing plate. That is, the portions described below simply as the properties of the polarizing plate may also be applied as physical properties of the pressure-sensitive adhesive layer or the adhesive layer. Further, among physical properties described in the present specification, for example, when the measurement temperature affects the result, each physical property may be physical property measured at room temperature unless otherwise specified. As used herein, the term ambient temperature is a natural temperature that is not warmed or warmed, and may be, for example, any temperature within the range of about 10 ° C to 30 ° C, such as about 23 ° C or about 25 ° C.

For example, the polarizing plate can be controlled so that the transmittance of light having a wavelength of 450 nm is higher than the transmittance of light having a wavelength of 550 nm and / or 650 nm. The term transmissivity in this application means a linear light transmittance unless otherwise specified, and such transmittance can be measured using, for example, NDH5000 (Nippon Densoku) equipment. In the case of the above-mentioned high reflection liquid crystal panel, for example, a panel having a structure in which a color filter including and not including a BM and a TFT exist on a lower substrate at the same time, the reflectance of light of a longer wavelength tends to be higher than that of a general liquid crystal panel, This tendency tends to lower the color tone in the dark state. On the other hand, the polarizer is controlled so that the transmittance of light having a wavelength of 450 nm is higher than the transmittance of light having a wavelength of 550 nm and / or 650 nm, thereby improving the visibility of the dark state in the high reflection liquid crystal panel, have.

The transmittance for the light having a 450 nm wavelength in a polarizing plate (T ₄₅₎ and the transmittance for the 550 nm wavelength (T ₅₅₎ and or 650 nm ratio for the light having a wavelength ratio of _{(T 65) (T 45 /} T 55 Or T ₄₅ / T ₆₅ ) can be adjusted at a proper ratio in consideration of the state of the liquid crystal panel to which the polarizing plate is applied.

For example, the ratio T ₄₅ / T ₅₅ is 1.03 or more, 1.035 or more, 1.04 or more, 1.045 or more, 1.05 or more, 1.055 or more, 1.06 or more, 1.065 or more, 1.07 or more, 1.075 or more, 1.08 or more, , 1.09 or more, 1.095 or more, 1.1 or more, 1.15 or more, or 1.2 or more. The ratio (T ₄₅ / T ₅₅ ) may be 2 or less, 1.5 or less, 1.3 or less, or 1.25 or less in other examples.

The ratio (T ₄₅ / T ₆₅₎ is 1.03 or more, 1.035 or more, or more than 1.04, 1.045, at least 1.05, at least 1.055, at least 1.06, 1.065 or more, 1.07 or more, more than 1.075, 1.08 or more, more than 1.085, 1.09 or more, 1.095 or more, 1.1 or more, 1.15 or more, 1.2 or more, 1.25 or more, or 1.3 or more. The ratio (T ₄₅ / T ₆₅ ) may be 2.5 or less, 2 or less, 1.5 or less, 1.45 or less or 1.4 or less in other examples.

The pressure sensitive adhesive layer or the adhesive layer included in the polarizing plate may have a transmittance of 50% to 96% with respect to the standard light source D65. The standard light source D65 may be a light source that emits light having a relative spectral distribution (300 nm-0.03 to 830 nm-60.31) as CIE main light having an average main-correlated color temperature of 6504K including an ultraviolet region. The transmittance of the standard light source D65 may be measured in any one of the spectral distributions or may be measured in the entire range of the spectral distributions.

In the polarizing plate, the transmittance (T ₄₅ ) with respect to light having a wavelength of 450 nm may be, for example, 80% or more, 85% or more, 90% or more, or 95% or more. The upper limit of the transmittance (T ₄₅ ) is not particularly limited, and can be adjusted within a range in which a predetermined ratio can be satisfied. For example, the transmittance (T ₅₅ ) with respect to light having a wavelength of 550 nm and the ratio (T ₆₅ ) with respect to light having a wavelength of 650 nm may be about 95% or less, 90% Or 75% or less. The lower limit of the ratio (T ₅₅ or T ₆₅ ) is not particularly limited, and may be, for example, about 60% or more.

The polarizing plate having the above-described optical characteristics can be applied to various display devices, particularly a display device including the above-described high reflection liquid crystal panel, thereby improving the visual acuity in the black state, that is, the dark state, and improving the contrast ratio.

The optical characteristics may be further controlled to ensure a more appropriate effect.

For example, the polarizer can display coordinates in a range of CIE (International Commission on Illumination) L * a * b * color space.

The CIE L * a * b * color space is a color space obtained by nonlinearly transforming the CIE XYZ color space based on the human vision antagonistic theory. In this color space, the L * value represents brightness, and when L * value is 0, it represents black, while when L * value is 100, it represents white. In addition, if the a * value is negative, it is a greenish color, and if it is positive, it is a color red or violet. If the b * value is a negative number, the color is shifted to a blue color. If the b * value is a positive value, the color is shifted to a yellow color.

The polarizing plate may have a -a * value of, for example, about 2 or less, 2 or less, 1.8 or less, 1.8 or less, 1.6 or less, or 1.6. The -a * value can be about 0.7 or more, about 0.9 or more, about 1.1 or more, about 1.3 or more, or about 1.4 or more.

The polarizer may have a b * value of about 4 or less, about 3.5 or less, about 3.5, about 3, about 3, about 2.5 or less than about 2.5. The b * value may be greater than about 1.5, greater than about 1.5, greater than about 2, or greater than about 2.5.

The polarizer may have a ratio (-b / a, hereinafter referred to as a C index) of the -a * value to the b * value of about 2.5 or less or about 2.5 or less. The C index may be greater than about 1, greater than about 1, greater than about 1.25, greater than about 1.25, greater than about 1.5, or greater than about 1.5.

The polarizer may satisfy any one or two or more of the a * value, the b * value, and the C index, or may satisfy all of the above. Such a polarizing plate can be applied to a liquid crystal panel, in particular, to the above-mentioned high reflection liquid crystal panel so as to maintain or maximize the merits of the liquid crystal panel, and to improve the disadvantage thereof, for example, in a dark state.

The reason for this is unclear, but the polarizer having the above-described optical characteristics can block or absorb light of long wavelength, for example, red to yellow, in the light from the liquid crystal panel, It is possible to improve the visual acuity of the image.

Each numerical value in the CIE L * a * b * color space is measured by a spectrophotometer having a polarizing plate attached to a liquid crystal panel, for example, the high reflection liquid crystal panel, and a detector in the form of an integrating sphere at the measurement position of the sample. (ex. CM-2600d, KONICA MINOLTA), and then measure it.

The polarizing plate may satisfy other functions required for the polarizing plate while exhibiting the above-described optical characteristics.

For example, the polarizing plate may have a transmittance Ts for non-polarized light of about 35% or more or about 40% or more. The transmittance Ts may be about 60% or less, about 55% or less, about 50% or less, or about 45% or less. The transmittance Ts may be, for example, the transmittance measured for one polarizing plate.

The polarizing plate preferably has a light absorption axis and a light transmission axis perpendicular thereto and has a transmittance (Tc) of about 0.01% or less for linearly polarized light having an angle in the range of about -5 to 5 degrees with respect to the light absorption axis , About 0.009% or less, about 0.006% or less, about 0.005% or less, about 0.004% or less, about 0.001% or less, or about 0.0009% or less. The transmittance Tc may be about 0.0001% or more. The transmittance Tc is obtained by scanning the overlapping state by angles so that the optical absorption axes of the respective polarizers are in the range of 0 to 360 degrees while the two polarizers are overlapped, (Tc) representing the transmittance. At least one polarizer of the two overlapping polarizing plates may be a polarizer according to the present application and the other polarizing plate may be a polarizing plate according to the present application or another polarizing plate, for example, a polarizing plate provided in the measuring equipment.

The polarizing plate may have a degree of polarization of about 99.9% or more or about 99.99% or more. The polarization degree in the present application is a numerical value calculated according to the following equation (1).

[Equation 1]

(%) = {(Tp - Tc) / (Tp + Tc)} ^1/2 100

In the formula (1), Tp is the transmittance of the polarizing plate with respect to the linearly polarized light forming an angle of about 85 to 95 degrees with the optical absorption axis of the polarizing plate, and Tc is within the range of about -5 to 5 degrees with the optical absorption axis of the polarizing plate Is the transmittance of the polarizing plate with respect to linearly polarized light forming an angle.

The transmissivity Tp in Equation 1 is obtained by scanning the overlapping state by angles such that the optical absorption axes of the respective polarizers are in the range of 0 to 360 degrees in a state where the two polarizers are overlapped in another example And the transmittance Tc may be a transmittance at a time point at which the smallest transmittance is exhibited at the time of the angle-dependent scan as described above.

The transmittance (Ts, Tc, Tp) is a value measured with respect to light of about 550 nm.

The polarizing plate exhibiting such transmittance and polarization degree can be applied to a liquid crystal panel to exhibit an excellent light transmission or blocking function.

The method of producing such a polarizing plate is not particularly limited. For example, the polarizing plate can be manufactured by adjusting the absorption rate of each polarizing element included in the polarizing plate, or by including a component capable of controlling the absorption rate of each wavelength in other elements included in the polarizing plate.

In one example, the above-described pressure-sensitive adhesive layer (the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer) and / or the adhesive layer may contain a dye or pigment for producing the polarizing plate.

As the dye or pigment, a dye or pigment having a maximum absorption wavelength of about 500 nm to 700 nm or about 550 nm or 650 nm may be used. As the dyes or pigments, those capable of satisfying the above-mentioned properties in known dyes that can be applied together with the synthetic resin can be appropriately selected. For example, solvent dyes or solvent pigments may be used as dyes or pigments. As the dye or pigment, for example, a metal complex salt dye, a metal complex salt pigment or a non-metallic oil dye can be used. As the metal complex salt dye or pigment, azo metal complex salt or phthalocyanine type dye or pigment may be used. As the non-metallic oil dyes, azo dyes, anthraquinone dyes, xantan dyes, arylmethane dyes, azine dyes and the like can be used. Solvent Yellow 19, C.I. Solvent Yellow 21, C.I. Solvent Yellow 32, C.I. Solvent Yellow 79, C.I. Solvent Yellow 81, C.I. Solvent Yellow 82, C.I. Solvent Yellow 162, C.I. Solvent Orange 5, C.I. Solvent Orange 6, C.I. Solvent Orange 45, C.I. Solvent Orange 54, C.I. Solvent Orange 56, C.I. Solvent Orange 99, C.I. Solvent Brown 37, C.I. Solvent Brown 58, C.I. Solvent Red 35, C.I. Solvent Red 109, C.I. Solvent Red 118, C.I. Solvent Red 119, C.I. Solvent Red 122, C.I. Solvent Red 160, C.I. Solvent Red 225, C.I. Solvent Blue 70, C.I. Solvent Violet 2, C.I. Solvent Black 25, C.I. Solvent Black 27, C.I. Solvent Black 35 or C.I. Solvent Black 45 and the like (manufactured by YEDAM CHEMICAL CO., LTD.).

When the pressure-sensitive adhesive layer and / or the adhesive layer contain a dye or a pigment, the ratio thereof is not particularly limited. For example, the ratio can be selected in consideration of the absorption characteristics of the dye or pigment, the range of the desired transmittance, and / or the physical properties of the pressure-sensitive adhesive layer or the adhesive layer which may be affected by the inclusion of the dye or pigment.

For example, the dye or pigment may be applied in a proportion of 0.01 wt% or more or 0.02 wt% or more in the pressure-sensitive adhesive layer or the adhesive layer. In another example, the ratio is 10 wt% or less, 9 wt% or less, 8 wt% or less, 7 wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less, .

The polarizer, the transparent film, the pressure-sensitive adhesive layer, or the adhesive layer contained in the polarizing plate are not particularly limited and can be formed using a known material as long as they exhibit optical characteristics in the above-mentioned range.

For example, the transparent film may be a protective film of a polarizer, a retardation film, or the like as described above, and may be formed using a material known to form the protective film or the like.

For example, the transparent film may be a film formed using a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier property, or isotropy. Examples of such resins include cellulose resins such as triacetyl cellulose (TAC), polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) Cyclic polyolefin resins such as norbornene resin, polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The transparent film may be present on one side or both sides of the polarizer, and when present on both sides, each transparent film may be the same or different. In addition to the protective film in the form of a film, a cured resin layer obtained by curing a thermosetting or photo-curable resin such as a (meth) acrylic resin, a urethane resin, an acrylic urethane resin, an epoxy resin or a silicone resin may be used as the transparent film.

As the retardation film, a general material can be applied. For example, a uniaxial or biaxially stretched birefringent polymer film or an orientation film of a liquid crystal polymer can be applied.

The thickness of the transparent film can be appropriately adjusted and is usually controlled within a range of 1 to 500 μm, 1 to 300 μm, 5 to 200 μm, or 5 to 150 μm from the viewpoints of workability such as strength and handleability, .

The above-described transparent film such as a protective film or a retardation film may be attached to the polarizer by the first pressure-sensitive adhesive layer or an adhesive or the like. Such a transparent film or the like may be subjected to adhesion treatment such as corona treatment, plasma treatment, primer treatment, Easy handling may be performed.

In addition, a hard coat layer, a low reflection layer, an antireflection layer, a sticking prevention layer, a diffusion layer, a haze layer, or the like may be present on the side of the transparent film opposite to the side attached to the polarizer. The properties of the polarizer can also be controlled by controlling the properties of these layers.

The polarizing plate may have various elements such as a reflection plate, a brightness enhancement film or a transflective plate in addition to the transparent film such as the protective film or the retardation film, and the type thereof is not particularly limited.

The polarizer included in the polarizing plate is a functional film or sheet capable of extracting only light vibrating in one direction from incident light while vibrating in various directions. As the polarizer, for example, a general polarizer known in the art such as a poly (vinyl alcohol) (PVA) polarizer can be used. Such a polarizer may be, for example, a form in which a dichroic dye is adsorbed and aligned on a PVA-based resin film, and the above-described control of the optical characteristics may be controlled by controlling the kind or ratio of the dichroic dye or the alignment state thereof It may be possible. The PVA resin constituting the polarizer can be obtained by, for example, gelling a PVAC (poly (vinyl acetate)) resin. As the PVAC resin, a homopolymer of vinyl acetate; And copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of the monomer copolymerizable with vinyl acetate include, but are not limited to, one or more kinds of monomers such as unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group. The degree of gelation of the PVA resin may be generally from 85 mol% to 100 mol% or 98 mol% or more. The PVA resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with an aldehyde may be used. The degree of polymerization of the PVA-based resin may be usually about 1,000 to 10,000 or about 1,500 to 5,000.

A known material can be applied to the polarizing plate of the present application, which is applied to the adhesion of the polarizer and the transparent film, and may optionally include the above-mentioned dyes or pigments, without any particular limitation. Examples of the adhesive include a PVA adhesive; Acrylic adhesive; Vinyl acetate based adhesive; Urethane based adhesives; Polyester-based adhesives; Polyolefin adhesives; Polyvinyl alkyl ether adhesives; Rubber adhesives; Vinyl chloride-vinyl acetate-based adhesive; Styrene-butadiene-styrene (SBS) adhesives; Hydrogenated styrene-butadiene-styrene (SEBS) based adhesives; Ethylenic adhesives; And acrylic ester-based adhesives, or a mixture of two or more thereof. The above-mentioned adhesive layer can be formed using, for example, an aqueous, solvent-based or solvent-free adhesive composition. The adhesive composition may be a thermosetting type, room temperature setting type, moisture setting type or photo setting type adhesive composition. Typical examples of the adhesive include water-based polyvinyl alcohol-based adhesives; Solventless acrylic adhesive; Or a solvent-free vinyl acetate-based adhesive.

The method of forming the above-mentioned adhesive layer on the polarizer is not particularly limited. For example, a method of applying the adhesive composition to a polarizer, then laminating the transparent film, and then curing the applied adhesive composition can be used have.

The thickness of the adhesive layer is not particularly limited, and can be adjusted to an appropriate thickness in consideration of desired optical characteristics, adhesion properties, and the like.

The first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer included in the polarizing plate may optionally contain a dye or a pigment as described above, and other known materials may be applied. In the above, the first pressure sensitive adhesive layer is to attach the above-mentioned transparent film and polarizer, and the second pressure sensitive adhesive layer can be used to adhere the polarizing plate to a liquid crystal panel or the like.

The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited and may be suitably selected and used as a base polymer, for example, a polymer such as acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether or fluorine- have. The adhesion of the pressure-sensitive adhesive layer to one surface or both surfaces of the polarizing plate can be carried out in an appropriate manner, and the manner thereof is not particularly limited.

With respect to the exposed surface of the second pressure sensitive adhesive layer, the release film may be temporarily adhered and covered for the purpose of prevention of contamination during practical use.

The pressure-sensitive adhesive layer can be formed, for example, by curing a usual room-temperature-curable, moisture-curable, thermosetting or photocurable pressure-sensitive adhesive composition. The curing of the pressure-sensitive adhesive composition described above means a state in which the pressure-sensitive adhesive composition is exposed to light by applying light, holding the pressure-sensitive adhesive composition at a predetermined temperature, or applying appropriate humidity, and exhibiting adhesive properties to the pressure-sensitive adhesive composition by physical action or chemical reaction. The term " photocurable pressure-sensitive adhesive composition " may mean a pressure-sensitive adhesive composition which can be cured by inducing crosslinking or polymerization reaction by irradiation of electromagnetic waves such as ultraviolet rays or electron beams.

The pressure-sensitive adhesive layer includes a pressure-sensitive adhesive containing one kind of crosslinking structure or two kinds of crosslinking groups and containing a so-called Interpenetrating Polymer Network (hereinafter, sometimes referred to as " IPN & Layer. The term " IPN " may refer to a state in which at least two kinds of crosslinking structures exist in the pressure-sensitive adhesive layer, and in one example, the crosslinking structures may be entanglement or linking or penetration penetrating. < / RTI >

In the case where the pressure-sensitive adhesive layer includes one kind of crosslinking structure, the pressure-sensitive adhesive layer may include, for example, an acrylic polymer crosslinked by a polyfunctional crosslinking agent. The term acrylic polymer as used in the present application means a polymer containing an acrylic monomer as a polymerization unit. For example, the acrylic monomer may be polymerized in an amount of more than 50%, 55%, 60%, 65% Or more, 70% or more, 75% or more, 80% or more, 85% or more, or 90% or more. In addition, the acrylic monomer may be acrylic acid, methacrylic acid or a derivative thereof (e.g., acrylic acid ester, methacrylic acid ester, or the like). Further, in the present application, the fact that a certain monomer is included in a polymer as a polymerization unit may mean a state in which the monomer undergoes a polymerization reaction to form a polymer skeleton of the polymer.

As the acrylic polymer crosslinked by the polyfunctional crosslinking agent, for example, an acrylic polymer having a weight average molecular weight (Mw) of 500,000 or more can be used. In the above, the weight average molecular weight is a conversion value for standard polystyrene measured by GPC (Gel Permeation Chromatograph). In this specification, unless otherwise specified, the term "molecular weight" means "weight average molecular weight". By setting the molecular weight of the polymer to 500,000 or more, a pressure-sensitive adhesive layer having excellent durability under severe conditions can be formed. The upper limit of the molecular weight is not particularly limited. For example, the durability of the pressure-sensitive adhesive and the coating property of the composition may be considered, and the upper limit of the molecular weight may be controlled within a range of not more than 2.5 million.

In one example, the acrylic polymer may be a polymer containing a (meth) acrylic acid ester monomer and a crosslinkable monomer as polymerized units, and may include, for example, 50 to 99.9 parts by weight of a (meth) acrylic acid ester- And 0.1 to 50 parts by weight of a crosslinkable monomer in a polymerized form. The term (meth) acrylic in the present application may mean acrylic or methacrylic. The term "crosslinkable monomer" as used herein means a monomer capable of copolymerizing with the (meth) acrylic acid ester monomer and capable of providing a crosslinkable functional group at the side chain or terminal of the polymer after copolymerization. Unless otherwise specified in the specification, the unit " parts by weight " means the ratio of the weights. The pressure-sensitive adhesive excellent in initial adhesion and durability can be provided by controlling the weight ratio of the monomer contained in the polymer as described above.

As the (meth) acrylic acid ester monomer, for example, alkyl (meth) acrylate can be used. In view of the cohesive force, glass transition temperature or tackiness of the pressure sensitive adhesive, alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms, Acrylate may be used. Examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl Acrylate, octyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate and tetradecyl (meth) acrylate.

The crosslinkable monomer may serve to control the durability, adhesion and cohesion of the pressure-sensitive adhesive. For example, the polymer may be provided with a nitrogen-containing functional group such as a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group or an amino group, Further, a monomer copolymerizable with the (meth) acrylic acid ester monomer may be used. Various monomers having the above-mentioned functions are known in the art, and all such monomers can be used. Examples of the crosslinking monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl , Hydroxy group-containing monomers such as 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethyleneglycol (meth) acrylate or 2-hydroxypropyleneglycol (meth) acrylate; (Meth) acryloyloxypropionic acid, 4- (meth) acryloyloxybutyric acid, acrylic acid dimer, itaconic acid, maleic acid, and Containing monomer such as maleic acid anhydride, or a nitrogen-containing monomer such as (meth) acrylamide, N-vinylpyrrolidone or N-vinylcaprolactam, and the like can be used. , But is not limited thereto.

The acrylic polymer may further contain, if necessary, any comonomer in a polymerized form.

The acrylic polymer may be prepared by applying a mixture of monomers containing the respective components described above to a conventional polymerization method such as solution polymerization, photopolymerization, bulk polymerization, suspension polymerization or emulsion polymerization have.

As the multifunctional crosslinking agent for crosslinking the acrylic polymer in the pressure-sensitive adhesive layer, for example, a common crosslinking agent such as an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent and a metal chelate crosslinking agent can be used, and isocyanate crosslinking agents are usually used, But is not limited thereto. Examples of the isocyanate crosslinking agent include multifunctional isocyanate compounds such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoboron diisocyanate, tetramethylxylene diisocyanate and naphthalene diisocyanate, N, N, N < / RTI > (N, N < ', N'-tetraglycidylethylenediamine, and glycerin diglycidyl ether. Examples of the aziridine crosslinking agent include N, N'-toluene-2,4-bis (1- Aziridine carboxamide), N, N'-diphenylmethane (1-aziridine carboxamide), triethylene melamine, bisisopropanoyl-1- (2-methyl aziridine) and tri-1-aziridinyl phosphine oxide , But is not limited thereto. Examples of the metal chelate crosslinking agent include compounds in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium and / or vanadium is coordinated to acetyl acetone or ethyl acetonate. It is not.

The ratio of the above-mentioned multifunctional crosslinking agent in the pressure-sensitive adhesive layer is not particularly limited, and may be selected in an appropriate range in consideration of, for example, the cohesive strength and durability of the pressure-sensitive adhesive.

The above-mentioned multifunctional crosslinking agent can react with the crosslinkable functional group of the acrylic polymer in the process of forming the pressure-sensitive adhesive layer such as an aging process to crosslink the polymer.

In the case of the IPN structure in which the pressure-sensitive adhesive layer comprises two or more crosslinking structures, the pressure-sensitive adhesive layer may be formed by, for example, crosslinking of the polyfunctional acrylate further polymerized to the crosslinking structure of the acrylic polymer crosslinked by the polyfunctional crosslinking agent Structure.

As the polyfunctional acrylate, any compound having two or more (meth) acryloyl groups in the molecule can be used without limitation. (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl Acrylate, neopentylglycol adipate di (meth) acrylate, hydroxyl puivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone- (Meth) acrylates such as cyclopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate, di (meth) acryloxyethyl isocyanurate, allyl cyclohexyl di (Meth) acrylates such as dimethanol (meth) acrylate, dimethylol dicyclopentanedi (meth) acrylate, ethylene oxide modified hexahydrophthalic acid di (meth) acrylate, tricyclodecanedimethanol Adamantane di (meth) acrylate or 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene (meth) acrylate or neopentyl glycol modified trimethyl propane di bifunctional acrylates such as fluorine and the like; (Meth) acrylates such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri Trifunctional acrylates such as modified trimethylolpropane tri (meth) acrylate, trifunctional urethane (meth) acrylate or tris (meth) acryloxyethylisocyanurate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; Pentafunctional acrylates such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate or urethane (meth) acrylate (e.g., an isocyanate monomer and trimethylolpropane tri Hexafunctional acrylates such as acrylonitrile, acrylonitrile, methacrylonitrile, acrylonitrile, methacrylonitrile and the like can be used. In some cases, various types of urethane acrylates, polycarbonate acrylates, polyester acrylates, polyether acrylates Or an epoxy acrylate may also be used.

The polyfunctional acrylates may be used singly or in combination of two or more. The use of acrylates having a molecular weight of less than 1,000 and trifunctional or more is advantageous in terms of durability, but the present invention is not limited thereto.

As the polyfunctional acrylate, those having a cyclic structure in the skeleton structure can be used. By using such an acrylate, contraction or swelling of the polarizer can be more effectively suppressed, and the light-shielding effect can also be improved. The ring structure included in the polyfunctional acrylate may be a carbon cyclic structure or a heterocyclic structure; Or a monocyclic or polycyclic structure. Examples of the polyfunctional acrylate containing a cyclic structure include monomers having an isocyanurate structure such as tris (meth) acryloxyethyl isocyanurate and monomers having an isocyanate modified urethane (meth) acrylate (e.g., an isocyanate monomer and trimethyl (Meth) acrylate, etc.), and the like, but the present invention is not limited thereto.

The proportion of the polyfunctional acrylate in the pressure-sensitive adhesive layer is not particularly limited, and can be adjusted in consideration of the cohesive force and durability of the pressure-sensitive adhesive, as in the case of a crosslinking agent.

The pressure-sensitive adhesive layer may further include a silane coupling agent. The silane coupling agent improves the adhesiveness and adhesion stability of the pressure-sensitive adhesive, improves the heat resistance and moisture resistance, and improves the adhesion reliability even when the pressure-sensitive adhesive is left for a long time under severe conditions. Examples of the silane coupling agent include, for example, gamma-glycidoxypropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-glycidoxypropyl tri Methacryloxypropyltrimethoxysilane, gamma-methacryloxypropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, Aminopropyltriethoxysilane, gamma-acetoacetate propyltrimethoxysilane, gamma-acetoacetate propyltriethoxysilane, beta-aminopropyltriethoxysilane, gamma-acetoacetate propyltriethoxysilane, gamma- Cyanoacetyltrimethoxysilane, beta-cyanoacetyltriethoxysilane, acetoxyacetotrimethoxysilane, and the like can be used, and one or more of the above- The can be used. In the present application, it may be advantageous to use a silane-based coupling agent having an acetoacetate group or a beta-cyanoacetyl group, but the present invention is not limited thereto. The ratio of the silane coupling agent in the pressure-sensitive adhesive layer is not particularly limited.

The pressure-sensitive adhesive layer may further include a tackifier resin. Examples of the tackifier resin include a hydrocarbon resin or a hydrogenated product thereof, a rosin resin or a hydrogenated product thereof, a rosin ester resin or a hydrogenated product thereof, a terpene resin or a hydrogenated product thereof, a terpene phenol resin or a hydrogenated product thereof, A resin or a polymerized rosin ester resin, or a mixture of two or more thereof. The ratio of the tackifying resin can also be suitably adjusted in consideration of the desired tackiness.

The pressure-sensitive adhesive layer may further optionally further comprise at least one additive selected from the group consisting of an epoxy resin, a curing agent, a UV stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, a defoamer, a surfactant and a plasticizer.

The method of forming the pressure-sensitive adhesive layer is not particularly limited. In one example, the pressure-sensitive adhesive layer may be prepared by a method of preparing a pressure-sensitive adhesive composition by blending the components described above, applying the pressure-sensitive adhesive composition to the polarizer or a suitable process substrate by a conventional means such as a bar coater or a comma coater, Can be used. The method of curing the pressure-sensitive adhesive composition is not particularly limited. For example, a method of aging at an appropriate temperature so that the crosslinking reaction of the acrylic polymer and the polyfunctional crosslinking agent proceeds, and a method of polymerizing the polyfunctional acrylate Or both of the above-described steps may be sequentially or simultaneously performed and cured. The irradiation of the electromagnetic wave in the above can be performed by means of, for example, a high-pressure mercury lamp, an electrodeless lamp, or a xenon lamp. The irradiation condition of the electromagnetic wave is not particularly limited as long as it is controlled so that polymerization of the polyfunctional acrylate can be appropriately performed without impairing all the physical properties. For example, when the illuminance is changed from 50 mW / cm 2 to 2,000 mW / cm 2 And the amount of light is controlled to 10 mJ / cm2 to 1,000 mJ / cm2, and irradiation can be performed for an appropriate time.

In view of the efficiency of the curing process by irradiation of the electromagnetic wave, the pressure-sensitive adhesive composition may contain a photo radical initiator (hereinafter, simply referred to as a photoinitiator). The photoinitiator is not particularly limited as long as it can generate a radical by irradiation of an electromagnetic wave and initiate a curing reaction. Examples of the photoinitiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethyl anino acetophenone, 2-methoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy- Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl- 2- , Benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethyl anthraquinone, 2-t-butyl anthraquinone, , 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethylketal, Dimethylamino benzoic acid There can be used stearyl, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] and 2,4,6-trimethylbenzoyl-diphenyl- have. In the present application, one kind or more kinds of the above can be used, but the present invention is not limited thereto.

The ratio of the photoinitiator is not particularly limited and may be selected within a range in which appropriate curing can be induced.

In addition, the polarizer, the transparent film, the pressure-sensitive adhesive layer and / or the adhesive layer included in the polarizing plate may be provided with an ultraviolet absorbing ability. Such an ultraviolet ray absorbing ability can be realized by, for example, including ultraviolet ray absorbers in appropriate proportions in each element. As the ultraviolet absorber, a salicylic ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound or a nickel complex salt compound may be used, but the present invention is not limited thereto.

The present application is also directed to a display device. The display device may include at least the polarizing plate. In one example, the display device may include a liquid crystal panel and the polarizer disposed on one side of the liquid crystal panel. At this time, the polarizing plate may be attached to the liquid crystal panel by, for example, the above-described second pressure sensitive adhesive layer. At this time, the polarizing plate may be included as an upper polarizing plate, i.e., a viewer-side polarizing plate. The liquid crystal panel may include an upper substrate and a lower substrate, and may include a liquid crystal layer between the upper substrate and the lower substrate. In this case, the liquid crystal panel may be a high-reflection liquid crystal panel, for example, a liquid crystal panel not including a BM. In addition, the liquid crystal panel may be a liquid crystal panel in which TFTs and color filters are both present on the lower substrate side. In such a structure, the polarizer or the polarizing plate can maintain or maximize the merits of the liquid crystal panel, and improve the disadvantage thereof, for example, the reflection and visibility characteristics in the dark state.

In one example, the display device may include an additional polarizer or polarizer (hereinafter referred to as a second polarizer or a second polarizer). For example, the above-mentioned polarizing plate (hereinafter referred to as a first polarizing plate) of the present invention is disposed on the upper side of the liquid crystal panel, that is, on the viewing side, and on the lower side, A polarizing plate may be disposed. In this case, the second polarizer or the second polarizer may be one which is adjusted to have a light blocking rate (light absorption rate or light reflectance) at, for example, a wavelength within a range of 380 nm to 520 nm of about 4 to 6 have. The manner of controlling the light blocking rate of the second polarizer or the second polarizer is not particularly limited, and a known method can be applied. When the first polarizer of the present invention is applied to the upper polarizer or the polarizer of the high reflection liquid crystal panel, if the optical characteristics of the second polarizer or the second polarizer are adjusted as described above, The characteristics can be greatly improved.

The specific structure of the high reflection liquid crystal panel is not particularly limited. For example, the liquid crystal panel may have a structure similar to that of a known liquid crystal panel except that BM is not included. In such a case, the color filter may be present on either substrate side of the upper and lower substrates, May be present on the lower substrate side. The type of the liquid crystal layer included in the liquid crystal panel is not particularly limited. For example, all known liquid crystal layers such as VA, IPS, TN, and STN can be applied.

The present application can provide a polarizing plate which can be applied to various types of display devices, particularly a display device including a high reflection liquid crystal panel, to improve the visual feeling in the dark state and to improve the contrast ratio. In the present application, a display device including the polarizer can also be provided.

Figs. 1 to 3 are diagrams showing transmittances for respective wavelengths of the respective polarizing plates in Examples. Fig.
4 is a graph showing the transmittance of the polarizing plate of the comparative example for each wavelength.
5 is a view showing the difference in reflectance between the general panel and the high reflection panel.
6 is a view showing the reflectance when the embodiment or the comparative example is applied to the high reflection panel.

Hereinafter, the polarizer and the like will be described in more detail through examples and the like according to the present application, but the scope of the present application is not limited to the following.

Each property of the polarizer and the like was measured in the following manner.

1. Measurement of physical properties

In the following examples, the transmittance and reflectance of each wavelength were measured using a UV-VIS-NIR Spectrophotometer (solidspec-3700, Shimadzu) according to the manufacturer's manual.

Manufacturing example 1. Preparation of acrylic polymer (A)

98 parts by weight of n-butyl acrylate (n-BA) and 2 parts by weight of 2-hydroxyethyl acrylate (2-HEA) were added to a 1 L reactor equipped with a cooling device to easily regulate the temperature, . Subsequently, 180 parts by weight of ethyl acetate (EAc) as a solvent was added to the reactor and nitrogen gas was purged for oxygen removal for 60 minutes. Thereafter, the temperature was maintained at 67 占 폚, and 0.05 parts by weight of AIBN (azobisisobutyronitrile) as a reaction initiator was added thereto, followed by reaction for 8 hours. After the reaction, the mixture was diluted with ethyl acetate to prepare an acrylic polymer (A) having a solid concentration of 30% by weight, a weight average molecular weight of 1,000,000, and a molecular weight distribution of 4.9.

Example One.

Second The pressure- Produce

, 100 parts by weight of an acrylic polymer (A), 0.01 part by weight of a polyfunctional crosslinking agent (TDI isocyanate, Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), a silane coupling agent (M812, a silane coupling agent having a beta-cyano acetyl group, LG (Manufactured by YEDAM CHEMICAL CO., LTD., Yellow S-3G, Red S-7G, Green 3-G and Blue S-RR in a weight ratio of 1: 0.9: 3: G: Red S-7G: Green 3-G: Blue S-RR) was added to a solvent to prepare a pressure sensitive adhesive composition having a solid concentration of 30% by weight. Then, the pressure-sensitive adhesive composition thus prepared was coated on the releasably treated PET release film (thickness: 38 mu m, MRF-38, manufactured by Mitsubishi Co., Ltd.) so that the thickness after drying was 25 mu m and dried in an oven at 110 DEG C for 3 minutes To form a second pressure-sensitive adhesive layer, and a PET release film (thickness: 38 mu m, MRF-38, manufactured by Mitsubishi) having been subjected to release treatment was additionally laminated.

Production of Polarizer

The PVA resin film was stretched, dyed with iodine, and then treated with an aqueous solution of boric acid to prepare a polarizer. Next, a 60 탆 thick TAC (triacetyl cellulose) film was attached to both sides of the polarizer using an aqueous polyvinyl alcohol adhesive. Then, the second pressure-sensitive adhesive layer prepared above was laminated on one TAC film of both PVA polarizers and the polarizing plate (polarizing plate structure: TAC film → water-based polyvinyl alcohol adhesive → polarizer → water-based polyvinyl alcohol adhesive → TAC film - > second pressure sensitive adhesive layer - > PET release film). The results of measuring the transmittance of each polarizing plate by wavelength are shown in FIG. 1 is a graph of the polarizing plate of Example 1. Fig.

Example 2.

In the preparation of the pressure-sensitive adhesive composition, a dye (Yellow S-3G: Red S-3G, Green 3-G and Blue S-RR in a weight ratio of 1: 0.9: -7G: Green 3-G: Blue S-RR) (0.15 part by weight) was used as a polarizing plate. The results of measuring the transmittance of each polarizing plate by wavelength are shown in FIG. The blue graph (intermediate graph) in FIG. 1 is a graph for the polarizer of Example 2. FIG.

Example 3.

In the preparation of the pressure-sensitive adhesive composition, a dye (Yellow S-3G: Red S-3G, Green 3-G and Blue S-RR in a weight ratio of 1: 0.9: -7G: Green 3-G: Blue S-RR) was used as a polarizing plate. The results of measuring the transmittance of each polarizing plate by wavelength are shown in FIG. In FIG. 1, the red graph (the lowest graph) is a graph for the polarizer of Example 3. FIG.

Example 4.

Except that 0.05 parts by weight of a dye (manufactured by Jadam Chemical Co., Ltd., Violet S-IRS, Green S-6G in a weight ratio of 1: 1.5 (Violet S-IRS: Green S-6G) A pressure-sensitive adhesive layer and a polarizing plate were prepared in the same manner as in Example 1. The results of measuring the transmittance of each polarizing plate by wavelength are shown in FIG. 2 is a graph of a blue color graph (upper graph) for the polarizer of Example 4. FIG.

Example 5.

Except that 0.3 part by weight of a dye (manufactured by Jadam Chemical Co., Violet S-IRS, Green S-6G containing 1: 1.5 by weight (Violet S-IRS: Green S-6G)) was used in the preparation of the pressure- A pressure-sensitive adhesive layer and a polarizing plate were prepared in the same manner as in Example 1. The results of measuring the transmittance of each polarizing plate by wavelength are shown in FIG. The red graph (lower graph) in FIG. 2 is a graph for the polarizer of Example 5. FIG.

Example 6.

A pressure-sensitive adhesive layer and a polarizing plate were prepared in the same manner as in Example 1, except that 0.05 parts by weight of pigment (Black pigment, Black-LMB1, IRIDOS) was used in preparing the pressure-sensitive adhesive composition. The results of measuring the transmittance of each polarizing plate by wavelength are shown in FIG. The red graph (upper graph) in FIG. 3 is a graph for the polarizer of Example 6. FIG.

Example 7.

A pressure-sensitive adhesive layer and a polarizing plate were prepared in the same manner as in Example 1, except that 0.1 parts by weight of pigment (Black pigment, Black-LMB1, IRIDOS) was used in the preparation of the pressure-sensitive adhesive composition. The results of measuring the transmittance of each polarizing plate by wavelength are shown in FIG. 3 is a graph of a blue color graph (lower graph) for the polarizer of Example 7. FIG.

Comparative Example One.

A pressure-sensitive adhesive layer and a polarizing plate were prepared in the same manner as in Example 1, except that no dye was added during the production of the pressure-sensitive adhesive composition. The results of measuring the transmittance of each polarizing plate by wavelength are shown in FIG.

Test Example

The optical characteristics of the polarizing plate were compared using a highly reflective liquid crystal panel (reflectance of about 18.18% for light of 550 nm wavelength) as a liquid crystal panel. The liquid crystal panel is a panel having a higher reflectance than a general liquid crystal panel (the reflectance for light with a wavelength of 550 nm is about 10.6%), FIG. 5 is a view showing the reflection characteristics of the general panel and the high reflection liquid crystal panel to be. As shown in the figure, a high reflection liquid crystal panel (HRL panel) exhibits a higher reflectance than a general liquid crystal panel.

6 is a graph showing the reflectance when the flat plate of Comparative Example 1 is applied to the upper polarizing plate and the reflectance when the polarizing plate of Example 2 is applied to the upper polarizing plate in the high reflection liquid crystal panel. In FIG. 6, an orange graph (a graph showing a high reflectivity for light with a wavelength of 550 nm) is applied to Comparative Example 1, and a black graph (a graph having a low reflectance with respect to light having a wavelength of 550 nm) to be.

It can be seen from the figure that by applying the polarizing plate according to the present invention to a highly reflective liquid crystal panel, the reflectance, particularly the reflectance at a long wavelength, can be greatly reduced, and the effect can be further increased when additional processing such as low- Points can be confirmed.

Claims

A polarizer; A transparent film attached to one surface of the polarizer by a first adhesive layer or an adhesive layer; And a second pressure-sensitive adhesive layer formed on a surface of the polarizer opposite to the surface on which the transparent film is adhered,
The transmittance of light having a wavelength of 450 nm is higher than the transmittance of light having a wavelength of 550 nm or 650 nm,
Wherein a transmittance of light having a wavelength of 450 nm is 80% or more.

The polarizing plate according to claim 1, wherein the ratio (T ₄₅ / T ₅₅ ) of the transmittance (T ₄₅ ) to the light having a wavelength of 450 nm and the transmittance (T ₅₅ ) to the light having a wavelength of 550 nm exceeds 1.02.

The polarizing plate according to claim 1, wherein the ratio (T ₄₅ / T ₆₅ ) of the transmittance (T ₄₅ ) to the light having a wavelength of 450 nm and the transmittance (T ₆₅ ) to the light having a wavelength of 650 nm exceeds 1.02.

The polarizing plate according to claim 1, wherein the permeability of the pressure-sensitive adhesive layer or the adhesive layer to the standard light source D65 is in the range of 50% to 96%.

The polarizing plate according to claim 1, wherein the pressure-sensitive adhesive layer or the adhesive layer comprises a dye or a pigment.

6. The polarizer according to claim 5, wherein the dye or pigment has a maximum absorption wavelength in the range of 500 nm or 700 nm.

The polarizing plate according to claim 5, wherein the dye or pigment is a solvent dye or pigment.

The polarizing plate according to claim 5, wherein the dye or pigment is a metal complex dye, a metal complex salt pigment or a non-metallic oil dye.

The polarizing plate according to claim 5, wherein the proportion of the dye or pigment in the pressure-sensitive adhesive layer or the adhesive layer is in the range of 0.02 to 1% by weight.

delete

The polarizer according to claim 1, which is applied to a liquid crystal panel having a reflectance of 12% or more with respect to light having a wavelength of 550 nm.

The polarizing plate according to claim 1, which is applied to the viewing side of a liquid crystal panel having a reflectance of 12% or more with respect to light having a wavelength of 550 nm.

The polarizing plate according to claim 1, wherein the transmittance (Ts) with respect to unpolarized light having a wavelength of 550 nm is 35% or more.

The optical element according to claim 1, wherein a transmittance (Tc) for linearly polarized light having a wavelength of 550 nm having an optical absorption axis and a light transmission axis orthogonal thereto and having an angle in the range of -5 to 5 degrees with respect to the optical absorption axis is 0.01 %.

The polarizing plate according to claim 1, wherein the polarization degree is 99.9% or more.

A display device comprising the polarizer of claim 1.

The display device according to claim 16, further comprising a liquid crystal panel having a reflectance of 12% or more with respect to light having a wavelength of 550 nm, wherein a polarizing plate is disposed on the viewer side of the liquid crystal panel.

The display device according to claim 17, further comprising a second polarizer or a second polarizer disposed on the back side of the liquid crystal panel.

The display device according to claim 18, wherein the second polarizer or the second polarizing plate has a light blocking factor in a range of 4 to 6 at any wavelength within a range of 380 nm to 520 nm.