JPH10111411A - Polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polarizing plate which has excellent polarization characteristics, excellent durability in a high-temp. and high-humidity state, and capable of sufficiently exhibiting the functions of various kinds of function layers even if these layers are laminated, by adopting a constitution that the thickness of a polarizing film and the thickness of a protective film satisfy a specific relation. SOLUTION: In the relation between the thickness (a) of the polarizing film of the polarizing plate formed by laminating the protective film on one surface of the polarizing film and the thickness of the protective film, (a)/(b) satisfies 1/5 to 1/1. The polarizing film to be used includes a polyvinyl alcohol(PVA)- based film, ethylene-vinyl alcohol based film, etc., and the polarizing film of the PVA-based resin is adequately used in terms of workability, etc. In the relation between the thickness (a) of the polarizing film provided with a tacky adhesive layer on the outer side of the protective film and the thickness of this tacky adhesive layer (c), (a)/(c) satisfies 1/3 to 2/1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polarizing plate, and more particularly to a polarizing plate excellent in optical durability (contrast retention) under high temperature and high humidity conditions and a polarizing plate provided with a functional layer.

[0002]

2. Description of the Related Art Conventionally, electronic desk calculators, electronic watches,
2. Description of the Related Art Liquid crystal display devices are used in word processors, instruments of automobiles and machinery, and the like. A polarizing plate is used in the liquid crystal display device. As the polarizing plate, a cellulose-based film such as a polyvinyl alcohol film to which polarizing properties are imparted by stretching or dyeing treatment is used. A polarizing plate on which a protective layer such as a cellulose acetate film is laminated is used.

[0003]

However, with the recent advancement of technology, the polarization (parallel transmittance / orthogonal transmittance) does not decrease even under conditions of high temperature and high humidity. A board is desired.

[0004]

In view of the above situation, the present inventors have conducted intensive studies on the thicknesses of the polarizing film and the protective film, and as a result, have found that the polarizing film of the polarizing plate having the protective film laminated on at least one side of the polarizing film. In the relationship between the thickness (a) of the film and the thickness (b) of the protective film, when (a) / (b) satisfies 1/5 to 1/1,
Good optical durability with no reduction in contrast (parallel transmittance / orthogonal transmittance) even under high temperature and high humidity conditions, and fully exhibit its function even when various functional layers are laminated. And completed the present invention. In the present invention, an optical laminate in which a protective film is provided on at least one side of a polarizing film is referred to as a polarizing plate, and the unit of each thickness is μm.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
Examples of the polarizing film used in the present invention include a polyvinyl alcohol-based film, an ethylene vinyl alcohol-based film, a cellulose-based film, and a polycarbonate-based film, and a polarizing film of a polyvinyl alcohol-based resin is preferable in terms of processability and the like. The film will be described below, but the present invention is not limited to the film.

The polyvinyl alcohol resin is usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. However, the present invention is not limited to this, and a small amount of unsaturated carboxylic acid may be used. (Including salts, esters, amides, nitriles, etc.), olefins, vinyl ethers, unsaturated sulfonates, and the like, may contain components copolymerizable with vinyl acetate. Further, polyvinyl butyral resin obtained by reacting a polyvinyl alcohol resin with an aldehyde in the presence of an acid, a so-called polyvinyl acetal resin such as a polyvinyl formal resin and other polyvinyl alcohol resin derivatives are also exemplified, but those not limited thereto. Absent. Among these, polyvinyl alcohol (based resin) having a high degree of saponification and a high degree of polymerization is preferred from the viewpoint of good heat resistance.
That is, the saponification degree is preferably 95 mol% or more, and more preferably 9 mol%.
9 mol% or more, especially 99.5 mol% or more,
The (average) degree of polymerization is preferably 2500 to 6000, more preferably 2500 to 5000, particularly preferably 2500 to 4000.

As a method for producing a polarizing film using the polyvinyl alcohol-based resin, a stock solution obtained by dissolving the polyvinyl alcohol-based resin in water or an organic solvent is cast and formed.
Stretching and iodine-staining, stretching and dyeing simultaneously, or iodine-staining and stretching followed by treatment with a boron compound are employed. The protective film adhered to such a polarizing film may be one conventionally used as a protective film for a polarizing film, and is not particularly limited,
Usually, a cellulose-based film is used, and the cellulose-based film is made of cellulose diacetate, cellulose triacetate, cellulose tripropionate, cellulose tributyrate, or the like, and one or more of these are used. Among them, cellulose triacetate (cellulose triacetate) is preferably used. Such polarizing film and protective film (cellulose-based film)
For the lamination of, natural or synthetic rubber, acrylic resin, butyral resin, epoxy resin, polyester resin, polyamide resin, using an adhesive or pressure-sensitive adhesive mainly containing polyvinyl alcohol resin, etc. Adhesion can be performed by an air drying method, a chemical curing method, a thermosetting method, a hot melting method, or the like.

Thus, a polarizing plate having a laminated structure of a protective film / a polarizing film or a protective film / a polarizing film / a protective film can be obtained. In the present invention, the thickness (a) of the polarizing film of such a polarizing plate is obtained. ) And the thickness (b) of the protective film are represented by (a) / (b) =
The biggest feature is to make it 1/5 to 1/1,
Preferably, (a) / (b) = 1/3 to 1/1. That is, when the ratio (a) / (b) is less than 1/5 or more than 1/1, the contrast retention is reduced and the effect of the present invention cannot be obtained. In the present invention, the thickness of the polarizing film or protective film (cellulose-based film) obtained as described above is arbitrarily set or selected to satisfy (a) / (b) = 1/5 to 1/1. The thickness of each polarizing film is not particularly limited, but the thickness (a) of the polarizing film is usually 1 to 200 μm (more preferably 5 to 200 μm).
100 μm), and the thickness (b) of the protective film is 10 to
It is selected from about 200 μm (further 30 to 100 μm). When the protective film is provided on both sides of the polarizing film, the thickness of at least one of the protective film and the thickness of the polarizing film may satisfy the above conditions, and furthermore, the thickness of the protective film on both sides Preferably, each satisfies the above relationship.

Further, according to the present invention, the polarizing film (polarizing plate) obtained as described above has a wavelength of 460 nm and 640 nm.
The value (ratio) of parallel transmittance / perpendicular transmittance at 20 is 20
It is preferably at least 00. As a method for controlling the value of the parallel transmittance / direct transmittance, the dyeing treatment is performed twice or more in the production of the polarizing film, the temperature and time during the treatment with the boron compound are adjusted, It can be controlled by stretching during the treatment and adjusting the stretching speed, but is not limited to these.

The polarizing plate of the present invention obtained as described above is usually provided with a pressure-sensitive adhesive layer further provided on the protective film (cellulose-based film) surface and adhered to a glass substrate such as a liquid crystal display device. In the present invention, it is also useful to control the relationship between the thickness (c) of the pressure-sensitive adhesive layer and the thickness (a) of the polarizing film in the present invention, and (a) / (c ) = 1/3 to 2/1, more preferably (a) / (c) = 1/2 to 2/1. If (a) / (c) is less than １ ／ or (a) / (c) exceeds １ ／, the polarizing film is undesirably curled or the like, causing optical distortion. The thickness (c) of the pressure-sensitive adhesive layer is not particularly limited as long as it satisfies the above relationship, but is usually 1 to 100 μm (more preferably 5 to 50 μm).
Selected from degree. When the pressure-sensitive adhesive is provided on both surfaces, the relationship is the same as above. As such an adhesive,
Acrylic pressure-sensitive adhesive is preferably used, as the acrylic pressure-sensitive adhesive, a known one is used, and as a component of the acrylic resin which is a main component of the acrylic pressure-sensitive adhesive,
A soft main monomer component having a low glass transition temperature, a hard comonomer component having a high glass transition temperature, and a small amount of a functional group-containing monomer component as needed.

Specifically, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-acrylic acid
Ethylhexyl, lauryl acrylate, benzyl acrylate, alkyl acrylates having about 2 to 12 carbon atoms of alkyl groups such as cyclohexyl acrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, Benzyl methacrylate, a main monomer component such as alkyl methacrylate having about 4 to 12 carbon atoms of an alkyl group such as cyclohexyl methacrylate, and the comonomer component include methyl acrylate, methyl methacrylate, ethyl methacrylate, Examples thereof include alkyl methacrylates having 1 to 3 carbon atoms such as propyl methacrylate, vinyl acetate, acrylonitrile, methacrylonitrile, and styrene.

Other than the above, the functional group-containing monomer components include monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, polycarboxylic acids such as maleic acid, fumaric acid, citraconic acid, glutaconic acid and itaconic acid, and Carboxyl group-containing monomers such as anhydrides, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxylpropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, and the like In addition to hydroxyl group-containing monomers such as N-methylol acrylamide, (meth) acrylamide, dimethylaminoethyl methacrylate, glycidyl methacrylate, allyl glycidyl ether and the like can be mentioned.

[0013] Among such functional group-containing monomer components,
Particularly, use of a carboxyl group-containing monomer is preferred. Although the content of such a main monomer component cannot be unconditionally defined by the type or content of a comonomer component or a functional group-containing monomer component to be contained, it is generally preferable to contain the main monomer in an amount of 50% by weight or more. . The acrylic resin of the present invention is easily produced by a method well known to those skilled in the art, such as radical copolymerization of a main monomer, a comonomer, and, if necessary, a functional group-containing monomer in an organic solvent.

As the organic solvent used in the polymerization,
Aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as n-propyl alcohol and isopropyl alcohol; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. . Specific examples of the polymerization catalyst used in the radical polymerization include azobisisobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide and the like, which are ordinary radical polymerization catalysts.

The above-mentioned acrylic resin is mixed with additives such as a crosslinking agent and a coupling agent (silicone, aluminum, titanium) if necessary in an amount of 0.001 to 5% by weight. It becomes the acrylic pressure-sensitive adhesive. Examples of the crosslinking agent include isocyanate compounds, epoxy compounds, aldehyde compounds, amine compounds, metal salts, metal alkoxides, metal chelate compounds, ammonium salts, and hydrazine compounds. The amount of the crosslinking agent is 0.0% with respect to 100 parts by weight of the acrylic resin.
It is about 01 to 8 parts by weight. Thus, a polarizing plate provided with an adhesive layer is obtained, but in the present invention, various functional layers are laminated further outside the protective film (on the side where the adhesive layer is not provided). It is also useful to provide a polarizing plate with a functional layer.

As such a functional layer, specifically, an anti-glare layer, a hard coat layer, an anti-reflection layer,
Examples include a half-reflection layer, a reflection layer, a luminous layer, and an electroluminescence layer. Further, a combination of two or more types may be used. For example, a luminous layer and a reflective layer, a luminous layer and a half-reflection layer, a luminous layer and a light Examples include a combination of a diffusion layer, a light storage layer and an electroluminescence layer, a half reflection layer and an electroluminescence layer, and an antiglare layer and an antireflection layer. However, it is not limited to these.

The anti-glare layer is used to diffuse a reflected image of a fluorescent lamp or the like on the surface of the polarizing plate to make the display easier to see or to prevent the adhesion of fingerprints or the like. Melamine-based resin blended with an inorganic filler such as silica beads of 1 to 20 μm or an organic filler such as acrylic, styrene, divinylbenzene, melamine, benzoguanamine,
Urethane resin, acrylic resin, alkyd resin,
A thermosetting resin such as a silicone resin or an energy ray curable resin such as a polyfunctional acrylic ultraviolet ray or an electron beam is used, and a bar coat,
Coating is performed by a known coating method such as roll coating, gravure coating, and air knife coating. The thickness of the antiglare layer is about 1 to 20 μm.

The hard coat layer has a surface hardness of H (pencil hardness) or more to impart abrasion resistance. Specifically, a melamine resin, a urethane resin, an acrylic resin,
A thermosetting resin such as an alkyd resin, a silicone resin, or a polyfunctional acrylic resin is used as a main component, and an energy ray-curable resin such as an ultraviolet ray or an electron beam or a metal oxide such as SiO ₂ is used. Formed on the film surface. As a method for forming the layer, known coating methods such as bar coating, roll coating, gravure coating, and air knife coating are preferably used in the case of a resin, and a vacuum evaporation method is preferably used in the case of a metal oxide. . The thickness of the hard coat layer is about 1 to 20 μm.

The anti-reflection layer is for suppressing reflection of external light on the surface of the polarizing plate to make the display easier to see. Specifically, the anti-reflection layer is made of fluorine resin, SiO ₂ , MgF ₂ , Zr.
Metal oxides such as O ₂ , AlO ₃ and TiO ₂ are used,
It is formed on the surface of a cellulosic film. As a method for forming the layer, a known coating method such as bar coating, roll coating, gravure coating, or air knife coating is used in the case of a resin, and a vacuum deposition method is preferably used in the case of a metal oxide. The metal oxide is often laminated in two or more layers, and the thickness of the anti-reflection layer is 0.05 to 1 μm.
m. It is also effective to use a combination of an anti-reflection layer and an anti-glare layer.

The half-reflection layer is used to reduce power consumption by displaying a display using reflection of external light during the daytime and using light transmitted from a backlight at nighttime. , Scale-like mica, titanium dioxide-coated mica, plate-like fish scale foil, hexagonal plate-like basic lead carbonate, bismuth oxychloride, etc., fine mica or pearl pigments, glass products such as fine glass beads, crushed glass particles, plastic chips, plastics Using an adhesive containing transparent and / or translucent particles such as plastic products such as pulverized particles, a synthetic resin layer having optical transparency such as (meth) acrylic resin, acetate, polycarbonate, polyester, and polyurethane is formed. A film in which the transparent and / or translucent particles are adhered on the synthetic resin layer by bonding to a polarizing plate or a polarizing plate via an adhesive. Ri a method such as to adjust them is taken, the present invention is not limited to this. The polarizing plate with a half-reflection layer is practically used as a lower polarizing plate of a liquid crystal panel, and the cellulose-based film surface on which the half-reflection layer is not provided, that is, the half-reflection layer is not provided, is attached to the liquid crystal panel. Are combined.

The reflective layer is used for displaying a display by using external light reflection in the daytime and omitting a backlight, and specifically, a cellulose acetate film such as a cellulose triacetate film or a polyethylene terephthalate ( A metal having high reflectance, such as aluminum or silver, is deposited on a substrate such as PET (PET), and is bonded to a polarizing plate (one cellulose-based film) via an adhesive. The polarizing plate with a reflective layer is practically used as a lower polarizer of a liquid crystal panel, and the other cellulose-based film surface without the reflective layer is bonded to the liquid crystal panel so that the reflective layer is a lower layer. Is done.

The light-storing layer is for storing display light in the daytime without a backlight by storing external light in the daytime. Specifically, the light-storing layer is made of zinc sulfide or calcium sulfide as a base material. A green phosphor obtained by adding copper as an activator thereto, mixing a flux, and sintering the mixture is often used.Also, the phosphorescent paint contains an element that emits α-ray or β-ray such as radium or strontium. It is used as a light-emitting paint that emits light by itself in addition to a trace amount. The phosphorescent layer is coated on one side (one cellulose film) of a polarizing plate together with a binder resin such as an acrylic resin, and the polarizing plate with the phosphorescent layer is practically used as a lower polarizing plate of a liquid crystal panel. The other cellulosic film surface not provided with a luminous layer is bonded to a liquid crystal panel so as to be a lower layer. It is also effective to provide a reflective layer below the luminous layer or to provide a half-reflection layer between the luminous layer and the polarizing plate.

The electroluminescent layer is intended to reduce the weight and thickness in place of the conventional backlight, and is practically provided further below the lower polarizing plate of the liquid crystal panel. As an electroluminescent material,
There are an inorganic material and an organic material, and the inorganic material includes phosphor particles such as zinc sulfide, and the organic material is tris (8-quinolinolato) aluminum complex.
Bis (benzoquinolinolato) beryllium complex and the like can be mentioned. In actual use, an ITO electrode is provided on one side (the polarizing plate side) of the electroluminescent layer, and a dielectric layer and a back electrode are provided on the other side, and current is passed through the ITO electrode and the back electrode to emit light. It is also effective to provide a light storage layer or a half reflection layer between the electroluminescence layer and the polarizing plate.

In the present invention, by providing the above-mentioned various functional layers on the polarizing plate, or by providing the various kinds of functional layers on the polarizing plate in various combinations as described above, excellent optical performance and high temperature and high humidity conditions are provided. It has an excellent effect on durability underneath.

Thus, the polarizing plate of the present invention has excellent polarization characteristics and can be laminated with various functional layers.
It has excellent durability in high humidity conditions, fully demonstrates the functions of various functional layers, liquid crystal display devices such as electronic desktop calculators, electronic watches, word processors, instruments for automobiles and machinery, sunglasses, eyeglasses, Stereo glasses, display elements (CRT, LCD, etc.)
Reflection reducing layer, medical equipment, building materials, toys, etc., and is particularly useful for liquid crystal display devices such as instruments for automobiles and machinery.

[0026]

EXAMPLES The polarizing plate of the present invention will be described in more detail with reference to examples. In the examples, “%” is based on weight unless otherwise specified. The degree of polarization in the present invention is represented by the following equation. _{[(H 11 -H 1) / (} H 11 + H 1) ] ^1/2 × 100
(%) Where H ₁₁ at the time of superposition of two polarizing film sample, transmittance orientation direction was measured using a spectrophotometer in a state superimposed so as to become the same direction of the polarizing film (%) , H ₁ at the time of superposition of the two samples, the transmittance orientation direction was measured in the stacked state so as to be mutually orthogonal directions of the polarizing film (%).

Example 1 A polyvinyl alcohol-based polarizing film having a thickness of 25 μm (a) (average degree of polymerization: 3500, average degree of saponification: 99.5 mol%, stretched 5 times, parallel transmittance / direct transmittance at wavelengths of 460 nm and 640 nm) Value (ratio is 2400), a 50 μm thick (b) cellulose triacetate-based film was applied as a protective film using a polyvinyl alcohol-based adhesive (3% aqueous solution, dry applied thickness 0.01 μm) on both sides, After drying at 100 ° C. for 1 minute, a polarizing plate of the present invention was obtained. ((A) / (b) = 25 μm / 50 μm = 1/2) The contrast (parallel transmittance / orthogonal transmittance) of the obtained polarizing plate was measured using a high-speed multi-wavelength birefringence measuring device (manufactured by Otsuka Electronics Co., Ltd., R
It was 2400 when measured by ETS-2000 (measurement wavelength: 460 nm). Next, in order to examine the durability of the polarizing plate, the polarizing plate was left under a condition of 65 ° C. and 95% RH for 30 minutes, and was left in a dry state at + 55 ° C. for 30 minutes.
After repeating 0 times, the contrast was measured in the same manner as described above. As a result, the contrast retention rate was 1500, and the contrast retention rate was about 63%.

Example 2 In Example 1, the thickness (a) of the polarizing film was changed to 10 μm.
((A) / (b) = 10 μm / 30 μm = 1 /
Except for 3), a polarizing plate was obtained in the same manner, and the evaluation was performed in the same manner.

Example 3 An acrylic pressure-sensitive adhesive layer (50 μm thick) was provided outside the protective film in Example 1 ((a) / (c) = 25).
(μm / 50 μm = １ ／), and the same evaluation was performed.

Comparative Example 1 In Example 1, the thickness (a) of the polarizing film was set to 10 μm.
m, and the thickness (b) of the protective film was set to 60 μm ((a) / (b) = 10 μm / 60 μm = 1/6).

Comparative Example 2 In Example 1, the thickness (a) of the polarizing film was set to 20 μm.
m, the thickness (b) of the protective film was 15 μm ((a) / (b) = 20 μm / 15 μm = 1 / 0.7)
Except for 5), the same procedure was performed to obtain a polarizing plate, and the same evaluation was performed.

Comparative Example 3 A polarizing plate was obtained in the same manner as in Comparative Example 2, except that a polarizing film having a parallel transmittance / direct transmittance value (ratio) of 1800 at wavelengths of 460 nm and 640 nm was used.
Evaluation was performed similarly. Table 1 shows the test results of the examples and the comparative examples.

[Table 1] * Contrast measurement wavelength is 460nm

Example 4 A functional layer as shown in Table 2 was provided on one surface of the polarizing plate obtained in Example 1, and the functional evaluation of the polarizing plate with various functional layers was evaluated by the following method. (Anti-glare layer) Diffusivity of fluorescent lamp The display quality of the image when the fluorescent lamp was transferred to the polarizing plate was evaluated according to the following criteria. A: The shape of the fluorescent lamp could not be recognized B: The shape of the fluorescent lamp could be recognized Change in haze value The haze value before and after the polarizing plate was left under the above conditions was measured and evaluated according to the following criteria.・ ・ ・: Change rate of haze value before and after leaving less than 30% ×: Change rate of haze value before and after leaving is 30% or more

(Hard Coat Layer) Scratch resistance The surface of the polarizing plate was coated with steel wool at 1 kg / cm ² .
The presence or absence of scratches when rubbed 0 times was measured and evaluated according to the following criteria. ○ ・ ・ ・ No scratch × ・ ・ ・ Scratch Surface pencil hardness The surface hardness of the polarizing plate was measured according to JIS K 5400 and evaluated according to the following criteria. ○ ・ ・ ・ having surface hardness of H or more × ・ ・ ・ having surface hardness of less than H

(Anti-reflection layer) Reflection of fluorescent lamp The display quality of the image when the fluorescent lamp was transferred to the polarizing plate was evaluated according to the following criteria. A: Other display is not hindered by the reflection of the fluorescent lamp B: Other display is hindered by the reflection of the fluorescent lamp Surface reflectance Reflectivity before and after the polarizing plate is left under the above conditions Measure
Evaluation was made according to the following criteria. ○ ・ ・ ・ Change rate of reflectance before and after leaving is less than 30% × ・ ・ ・ Change rate of reflectance before and after leaving is 30% or more

(Half-reflection layer) Actual display quality at night and daytime At night and daytime, the display of the polarizing plate was evaluated according to the following criteria. A: Notation can be recognized in a short time at night and daytime B: Notation cannot be recognized in a short time at night and daylight Transmittance The transmittance of the polarizing plate before and after being left under the above conditions is measured,
Evaluation was made according to the following criteria.・ ・ ・: Change in transmittance before and after standing is less than 30% ×: Change in transmittance before and after standing is 30% or more Reflectivity Measure reflectance before and after leaving the polarizing plate under the above conditions And
Evaluation was made according to the following criteria. ○ ・ ・ ・ Change rate of reflectance before and after leaving is less than 30% × ・ ・ ・ Change rate of reflectance before and after leaving is 30% or more

(Reflective layer) Daytime display quality The display of the polarizing plate was evaluated in the daytime according to the following criteria. A: The notation can be recognized in a short time B: The notation cannot be recognized in a short time Reflectance The reflectance before and after the polarizing plate is left under the above conditions is measured.
Evaluation was made according to the following criteria. ○ ・ ・ ・ Change rate of reflectance before and after leaving is less than 30% × ・ ・ ・ Change rate of reflectance before and after leaving is 30% or more

(Luminescent layer) Actual display quality at night The display of the polarizing plate at night was evaluated according to the following criteria. A: The notation is recognizable. B: The notation is not recognizable. Surface luminance The luminance before and after the polarizing plate was left under the above conditions was measured and evaluated according to the following criteria.・ ・ ・: Change rate of luminance before and after leaving less than 30% ×: Change rate of luminance before and after leaving is 30% or more

(Electroluminescence layer) Actual display quality at night The display of the polarizing plate was evaluated at night according to the following criteria. A: Notation can be recognized in a short time B: Notation can not be recognized in a short time Surface luminance The luminance before and after the polarizing plate is left under the above conditions is measured, and based on the following criteria. evaluated.・ ・ ・: Change rate of luminance before and after leaving less than 30% ×: Change rate of luminance before and after leaving is 30% or more

[0040]

[Table 2] Functional layer Structure of functional layer Film thickness (μm) (1) AG layer Coated with 1% silica filler having a particle size of 3 μm in acrylic resin (2) HC layer Coated with acrylic resin 1 ( 3) AR layer Coated with fluorocarbon resin 0.1 (4) HR layer Coated with 10 to 10% of titanium dioxide-coated mica in an acrylic resin (5) GR layer A film obtained by depositing silver on a PET film by 1 Lamination (6) Luminescent layer Coated with acrylic resin mixed with 5% zinc sulfide and 5% copper to 5% luminous material (7) EL layer Bis (benzoquinolinolate) beryllium complex in acrylic resin 5% those that have been formulated and coated on PE T film, further laminating a material obtained by forming the transparency electrode of ITO Note) AG layer: anti-glare layer, HC layer: hard coat layer, AR layer: Anchiri Reflection layer, HR layer: half reflection layer, GR layer: reflection layer, EL layer: electroluminescence layer, PET: polyethylene terephthalate

Table 3 shows the evaluation results of Example 4.

[Table 3] Note) In the table, the evaluation of the functional layer ~
Show.

[0042]

The polarizing plate of the present invention controls the thickness of the polarizing film and the protective film in a specific relationship, so that the polarizing plate has excellent polarization characteristics and excellent durability under high temperature and high humidity conditions. Even if various functional layers are laminated, the function is fully exhibited, and liquid crystal display devices such as electronic desk calculators, electronic watches, word processors, instruments for automobiles and machinery, sunglasses, eye-protection glasses, stereo glasses, and display elements (CRT, LCD, etc.)
And is particularly useful for liquid crystal display devices such as instruments for automobiles and machinery.

Claims (5)

[Claims] 1. The thickness (a) of a polarizing film of a polarizing plate having a protective film laminated on at least one surface of the polarizing film.
And the thickness of the protective film (b), (a) /
(B) The polarizing plate, wherein 1/5 to 1/1 is satisfied. 2. In the relationship between the thickness (a) of the polarizing film and the thickness (c) of the pressure-sensitive adhesive layer of a polarizing plate having a pressure-sensitive adhesive layer provided outside the protective film, (a) / (c) is 1 /. 3-2
2. The polarizing plate according to claim 1, wherein the ratio is satisfied. 3. An average degree of polymerization of 2,500 as a polarizing film.
The polarizing plate according to claim 1, wherein a polyvinyl alcohol-based film having a thickness of from 6000 to 6000 is used. 4. The polarizing plate according to claim 1, wherein a functional layer is provided outside the protective film. 5. The method according to claim 1, wherein the functional layer comprises at least one of an anti-glare layer, a hard coat layer, an anti-reflection layer, a half-reflection layer, a reflection layer, a light storage layer, an electroluminescence layer, and a light diffusion layer. Item 6. A polarizing plate according to item 4.