JP2001311827A - Polarizing plate and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate capable of displaying more neutral gray white and black with high contrast and further to provide a method for manufacturing the same. SOLUTION: The polarizing plate comprising a polarizing film of which at least the one surface is laminated with a protective film through an adhesive layer, having >=40% single body transmittance, having a* and b* of perpendicular hue measured by JIS Z 8729 in -5.0<=a*<=10 and -10<=b*<=1.0 ranges respectively, having a* and b* of parallel hue in -4.0<=a*<=4.0 and -1.0<=b*<=5.5 ranges respectively and further having either of the layers comprising it having an absorption spectrum satisfying relations 0<=A/D<=0.3, 0.1<=B/D<=0.7, 0.5<=C/D<=1.4 and 0 <=E/D<=0.5 where absorbance at 450 nm, 500 nm, 550 nm, 600 nm and 650 nm are denoted as A, B, C, D and E respectively and the method for manufacturing it are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polarizing plate and a method for manufacturing the same.

[0002]

2. Description of the Related Art A polarizing film in which a dichroic substance is adsorbed and oriented on a polyvinyl alcohol resin film is usually used as one of members for a liquid crystal display device in the form of a polarizing plate having a protective film attached to at least one surface. ing.
However, when a conventional polarizing plate is used for a liquid crystal display device, particularly for a reflection type liquid crystal display device, there is a problem that a white display of the liquid crystal display device looks yellow. In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. 62-134625 and
JP-A-304624 reports that by changing the shape of the transmission spectrum of a polarizing plate, the coloring of white display of a liquid crystal display device can be suppressed.

However, the polarizing plates described in each of the above publications have a lower degree of polarization than the commonly used polarizing plates, and the orthogonal hues are shifted in the blue direction. Therefore, in a liquid crystal display device using such a polarizing plate, although white display is certainly a so-called neutral gray, there is a problem that the contrast is lowered due to the low degree of polarization, and the black display is colored blue. And a vivid display was not possible. In recent years, the transition of various liquid crystal display devices to color and reflective types has been progressing at a rapid pace, and the development of neutral gray polarizers capable of displaying both white display and black display in neutral gray and high contrast has been developed. It has been demanded.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present inventors
A more neutral gray white display and black display are possible,
As a result of intensive research to develop a polarizing plate having a higher contrast, it was found that a problem can be solved by disposing a colored layer having a specific absorption spectrum at an arbitrary position on an existing polarizing plate. Reached. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a polarizing plate capable of performing neutral gray white display and black display and having higher contrast, and to provide a method of manufacturing a polarizing plate which is advantageous for that purpose.

[0005]

That is, the present invention relates to a polarizing plate comprising a polarizing film and a protective film laminated on at least one surface of the polarizing film via an adhesive layer.
% Or more, and a ^* and b ^* of orthogonal hues measured based on JIS Z8729 are in the range of −5.0 ≦ a ^* ≦ 10 and −10 ≦ b ^* ≦ 1.0, respectively, and are also parallel. A ^* and b ^{* of the} hue are in the range of −4.0 ≦ a ^* ≦ 4.0 and −1.0 ≦ b ^* ≦ 5.5, respectively, and any one of layers constituting the polarizing plate Has an absorbance at a wavelength of 450 nm of A, and a wavelength of 500 nm.
Is B, the absorbance at 550 nm is C, the absorbance at 600 nm is D, and the wavelength is 65.
When the absorbance at 0 nm is E, the following formulas (I) to (I)
It is intended to provide a polarizing plate having an absorption spectrum that satisfies all the relationships of V).

0 ≦ A / D ≦ 0.3 (I) 0.1 ≦ B / D ≦ 0.7 (II) 0.5 ≦ C / D ≦ 1.4 (III) 0 ≦ E / D ≦ 0 .5 (IV)

According to the present invention, when manufacturing a polarizing plate by laminating a protective film on at least one surface of a polarizing film via an adhesive layer, any of the layers constituting the polarizing plate has an absorbance at a wavelength of 450 nm. A, wavelength 5
When the absorbance at 00 nm is B, the absorbance at 550 nm is C, the absorbance at 600 nm is D, and the absorbance at 650 nm is E, the above formula (I)
There is also provided a method for producing a polarizing plate by adding a colorant to the layer so as to show an absorption spectrum satisfying all the relationships of (IV).

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polarizing plate of the present invention is obtained by laminating a protective film on at least one side of a polarizing film via an adhesive layer. A polarizing film constituting this polarizing plate is usually produced by adsorbing and orienting a dichroic dye such as iodine or a dichroic dye on a uniaxially stretched polyvinyl alcohol resin film.

The polyvinyl alcohol resin constituting the polarizing film can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith. Examples of monomers copolymerizable with vinyl acetate include, for example, unsaturated carboxylic acids, olefins,
Examples include vinyl ethers and unsaturated sulfonic acids. The saponification degree of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 to 100 mol%.
Range. The polyvinyl alcohol resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of polyvinyl alcohol resin is
Usually in the range of 1,000 to 10,000, preferably 1.5
It is in the range of 00 to 10,000.

[0010] This polyvinyl alcohol resin film is uniaxially stretched and dyed with a dichroic dye, and then treated with boric acid. For uniaxial stretching, the film may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Further, it may be dry stretching in which stretching is performed in the air, or wet stretching in which stretching is performed in a state swollen with a solvent. Stretching ratio is usually 4
About 8 times. Such a stretched and oriented polyvinyl alcohol resin film is dyed with a dichroic dye.

When iodine is used as the dichroic dye, for example, the polyvinyl alcohol resin film may be immersed in an aqueous solution containing iodine and potassium iodide. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by weight per 100 parts by weight of water,
The content of potassium iodide is usually about 0.5 to 10 parts by weight per 100 parts by weight of water. The temperature of such an aqueous solution is usually about 20 to 40 ° C., and the immersion time is usually 3
It is about 0 to 300 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, for example, a polyvinyl alcohol resin film may be immersed in an aqueous solution of the dichroic dye. The content of the dichroic dye in such an aqueous solution is usually about 0.001 to 0.1 part by weight, preferably about 0.1 part by weight, per 100 parts by weight of water.
Not more than 01 parts by weight. This aqueous solution may contain an inorganic salt such as sodium sulfate. The temperature of such an aqueous solution is usually about 20 to 80 ° C., and the immersion time is usually about 30 to 300 seconds.

The boric acid treatment is performed, for example, by immersing a uniaxially stretched polyvinyl alcohol resin film dyed with a dichroic dye in a boric acid aqueous solution. The content of boric acid in the boric acid aqueous solution is usually about 2 to 15 parts by weight, preferably about 5 to 12 parts by weight per 100 parts by weight of water. The temperature of the boric acid aqueous solution is usually 50 ° C or higher, and preferably 50 to 85 ° C. The immersion time is usually about 100 to 1,200 seconds, preferably 150 to 60 seconds.
It is about 0 seconds, more preferably about 200 to 400 seconds. When the dichroic dye is iodine, the boric acid aqueous solution may contain potassium iodide. When the boric acid aqueous solution contains potassium iodide, the amount is usually 100 parts of water.
About 0.1 to 20 parts by weight per part by weight, preferably 2 to 20 parts by weight
It is about 18 parts by weight, more preferably about 5 to 15 parts by weight.

The uniaxial stretching may be performed before dyeing,
It may be performed simultaneously with the dyeing or after the dyeing. When the uniaxial stretching is performed after the dyeing, the uniaxial stretching may be performed before the boric acid treatment or may be performed during the boric acid treatment. Of course, it is also possible to perform uniaxial stretching in a plurality of stages among these.

The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed by, for example, immersing the boric acid-treated polyvinyl alcohol resin film in water. In the water washing treatment, the temperature of water is usually about 5 to 40 ° C., and the immersion time is usually about 2 to 120 seconds. Next, a drying treatment is performed, and the drying temperature is usually 100 ° C. or less, preferably 40 to
95 ° C. Drying time is usually 120 to 600
On the order of seconds.

The polarizing film thus obtained is formed into a polarizing plate by laminating a protective film on one side or both sides as in the usual case. As a protective film, for example,
Cellulose acetate resin films such as triacetyl cellulose and diacetyl cellulose, acrylic resin films, polyester resin films, polyarylate resin films, polyether sulfone resin films, and cyclic polyolefin resin films such as polynorbornene resin films, and the like. The thickness is usually 30 to
It is about 200 μm. Usually, a transparent and optically isotropic adhesive is used for lamination, and as the adhesive, for example, a polyvinyl alcohol-based adhesive is used.

The polarizing plate thus obtained may have a hard coat layer, an antireflection layer, an antiglare layer, etc. on the surface. Usually, at least one surface of the polarizing plate is coated with an adhesive.

In the present invention, wavelengths of 450 nm, 500 nm, 5
There is a layer having an absorption spectrum in which the absorbances A, B, C, D and E at 50 nm, 600 nm and 650 nm all satisfy the relations of the above formulas (I) to (IV). The meanings of the formulas (I) to (IV) are as follows: when the absorption spectrum of the layer is measured, the absorbances A, B, C, and E at 450 nm, 500 nm, 550 nm, and 650 nm relative to the absorbance D at 600 nm.
, That is, the relative absorbance satisfies a specific relationship. In order to form a layer having such a specific absorption spectrum, it is usually appropriate to color using a coloring agent such as a dye or a pigment.

The dye or pigment used to form such a colored layer may have dichroism, but preferably does not have dichroism. On the other hand, when a dye or pigment having dichroism is used, it is important that the dye or pigment not be highly oriented in the colored layer. In order to satisfy the relations of the formulas (I) to (IV), one kind of dye or pigment may be appropriately selected, or two or more kinds of dyes or pigments may be mixed and used.

The dyes are classified into, for example, disperse dyes, acid dyes and direct dyes, and more specifically, Disperse and Aci in the Color Index.
Dyes classified as d or Direct are suitable. In order to satisfy the relations of the formulas (I) to (IV) defined in the present invention, a violet dye is particularly suitable. Suitable dyes are identified by the Color Index Generic Name
generic name) and the corresponding product name (in parentheses)
For example, the following may be mentioned, and those having respective trade names are sold by Sumitomo Chemical Co., Ltd.

[0021] CI Disperse Violet 26 (“Sumikaron
Bordeaux SE-BL ”), CI Disperse Violet 28 (“ Su
mikaron Violet E-2RL ”), CI Disperse Violet 57
(“Sumikaron Brilliant Violet SE-BL”), CI Di
sperse Violet 77 (“Sumikaron Violet S-4RL extra c
onc. ”), CI Acid Violet 48 (“ Suminol Milling
Brilliant Violet B conc. "), CI Direct Violet
9 (“Nippon Brilliant Violet BK conc.”).

Among these, CI Direct Violet
9 is preferably used. Needless to say, these purple dyes may be mixed with dyes of other colors as needed. Further, the dye used in the present invention is not limited to these, and a dye or a pigment is appropriately selected so that the absorption spectrum satisfies the relations of the formulas (I) to (IV). Can be used.

In the present invention, a colored layer containing a dye or a pigment may be present in any layer of the polarizing plate so as to satisfy the relations of the formulas (I) to (IV). One or both sides of the film, in the protective film, the adhesive layer used to bond the protective film and the polarizing film, one or both sides of the polarizing film, in the polarizing film, or in any layer of the adhesive layer . In addition, for example, a neutral gray polarizing plate of the present invention can also be produced as a polarizing plate with a colored film by laminating a colored film on a polarizing plate, but the reason is that the polarizing plate itself becomes thicker and costs increase. Therefore, this method is not very suitable.

To provide a colored layer on one or both sides of the protective film, for example, a method in which a solution in which a water-soluble dye is dissolved in an aqueous polyvinyl alcohol solution is uniformly applied on the protective film and then air-dried, or an acrylic hard coat agent After dissolving or dispersing a dye or a pigment in the protective film, a method of applying the solution on a protective film and curing the solution or the like can be adopted. The coating may be performed by a commonly used method, for example, dipping or coating using various coaters. Further, a dye or a pigment may be deposited on the protective film.

In order to form the protective film into a colored layer, for example, a method of dissolving or dispersing a dye or a pigment in a raw material dope before forming the protective film, and then forming the film, a method of dyeing the protective film, and the like. Can be adopted. In order to make the adhesive layer for bonding the protective film and the polarizing film into a colored layer, for example, a dye or pigment is dissolved or dispersed in an adhesive before curing, and it is used in the same manner as a normal adhesive. Then, a method of attaching a protective film and a polarizing film to each other is used. When the protective film is provided on both surfaces of the polarizing film, it will be easily understood that the coloring adhesive may be used for either one or both. In order to form a colored layer on the surface or inside of the polarizing film, for example, a vapor deposition method, a dyeing method, a coating method, or the like can be employed. To make the pressure-sensitive adhesive layer a colored layer, for example,
A method of dissolving or dispersing a dye or pigment in the pressure-sensitive adhesive raw material is used. In the present invention, a colored layer may be present at any position on the polarizing plate, and the colored layer may be a single layer or a plurality of layers may be colored layers.

The amount of the dye or pigment is determined from the transmittance of the polarizing plate. The transmittance here is, for example, 10 nm at a predetermined wavelength interval dλ in a wavelength region of 400 to 700 nm.
In each case, the spectral transmittance τ (λ) is obtained, and is a value T calculated by the following equation (V).

[0027]

In the equation, P (λ) represents the spectral distribution of the standard light (C light source), and y (λ) represents the color matching function of the field of view twice.

The transmittance calculated from the spectral transmittance of one polarizing plate is called a single transmittance Ty, and the spectral transmittance when two polarizing plates are stacked so that their absorption axes are the same. Is referred to as the parallel position transmittance Tp, and the transmittance calculated from the spectral transmittance when two polarizing plates are stacked so that their absorption axes are orthogonal to each other is referred to as the orthogonal position transmittance Tc. Call.

In the present invention, the single transmittance Ty of the polarizing plate thus determined is set to be 40% or more.
If the amount of the dye or pigment present in the colored layer is too large,
The single transmittance Ty of the polarizing plate becomes too small, and the white luminance decreases. Further, when the single transmittance of a polarizing plate having a colored layer is T ₁ (%), and the single transmittance of a polarizing plate having exactly the same configuration except that no coloring agent is included is T ₀ (%),
The following formula (VI)

K = T ₀ −T ₁ (VI)

It is preferable to add a dye or pigment so that the K value obtained by the above becomes about 0.05 to 3, and more preferably about 0.1 to 2.5. If the K value is too small, a desired hue cannot be obtained. On the other hand, if the K value is too large, the transmittance of the polarizing plate decreases, and the white luminance when used in a liquid crystal display device decreases.

The degree of polarization Py can be obtained from the parallel transmittance Tp and the orthogonal transmittance Tc by the following equation (VII).
The polarizing plate of the present invention preferably has this degree of polarization of 99% or more.

[0034]

In the present invention, a polarizing plate according to JIS Z 8
729 (Color display method-L ^* a ^* b ^* color system and L ^* u ^* v ^*
A ^* and b ^* of the orthogonal hues measured by (color system) are in the range of −5.0 ≦ a ^* ≦ 10 and −10 ≦ b ^* ≦ 1.0, respectively, and a ^* and b of the parallel hues ^* Are in the ranges of −4.0 ≦ a ^* ≦ 4.0 and −1.0 ≦ b ^* ≦ 5.5, respectively.

The term "orthogonal hue" as used herein means that the measurement is carried out in a state where two polarizing plates are superposed so that their absorption axes are orthogonal to each other. This means that the measurement is performed in a state where the absorption axes are overlapped so as to be the same. In the L ^* a ^* b ^* color system, the closer the a ^* and b ^* are to zero, the more neutral the hue is. The method of displaying object colors defined in JIS Z 8729 is based on the Commission Internationale de l'Eclairage (Commission Internationale
de l'Eclairage, abbreviated as CIE) Publication CIE N
o. 15.2 (1986), COLORIMETRY, SECOND EDITION 4.
Corresponds to the display method of the object color defined in (1).

[0037]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

In the following examples, the evaluation of the polarizing plate was performed as follows. First, one polarizing plate and two polarizing plates
Using a spectrophotometer ("UV-2200" manufactured by Shimadzu Corporation) when the sheets are stacked so that their absorption axes are the same and when they are stacked so that the absorption axes are orthogonal,
The spectral transmittance τ (λ) was determined every 10 nm in the wavelength region of 400 to 700 nm, and the single transmittance Ty, the parallel transmittance Tp, and the orthogonal transmittance Tc were calculated from the above formula (V). Then, the parallel transmittance Tp and the orthogonal transmittance T
From c, the degree of polarization Py was determined by the above formula (VII). Hue is measured based on JIS Z 8729, and the value is expressed as L ^* a ^* b ^*
Displayed in chromaticity coordinates. In the L ^* a ^* b ^* color system, a ^* and b
^The closer to ^* , the neutral hue of the hue.

Control Example The following were prepared as a dye bath and an aqueous boric acid solution.

Dyeing bath: An aqueous solution containing 0.05 parts by weight of iodine and 5 parts by weight of potassium iodide per 100 parts by weight of water. Boric acid aqueous solution: 7.
An aqueous solution containing 5 parts by weight and 6 parts by weight of potassium iodide.

A polyvinyl alcohol film having a thickness of 75 μm, a degree of polymerization of 2,400 and a degree of saponification of 99.9% or more was uniaxially stretched by a dry method at a stretching ratio of 5 times. For 60 seconds. Next, while maintaining the tension state, it was immersed in the above-mentioned boric acid aqueous solution at a temperature of 73 ° C. for 300 seconds. Then, add 1% pure water at 15 ° C.
Washed for 0 seconds. The film after the water washing was dried at 70 ° C. for 300 seconds while keeping the film under tension, to obtain a polarizing film.

On the other hand, a 5% aqueous solution of completely saponified polyvinyl alcohol was used as the adhesive. This adhesive is applied to both sides of the polarizing film obtained above, and then a protective film made of triacetyl cellulose and saponified to a thickness of 80 μm (Fuji Photo "Fujitak UV80" manufactured by Film Co., Ltd.) was laminated and dried at 50 ° C. for 5 minutes to obtain a polarizing plate. For this polarizing plate, the single transmittance Ty, the degree of polarization Py, the parallel hues L ^* , a ^* and b ^* and the orthogonal hues L ^* , a ^* and b ^* were determined, and the results are shown in Table 1.

Example 1 20 g of a 5% aqueous solution of completely saponified polyvinyl alcohol
Sumitomo Chemical Co., Ltd. dye “Suminol Milling
"120 mg of Brilliant Violet B conc." Was dissolved and used as an adhesive. The same test as in the control example was carried out except that this adhesive was used, and the results are shown in Table 1. From the single transmittance of the polarizing plate and the single transmittance of the polarizing plate without a coloring layer obtained in the control example, the K value was determined by the above formula (VI), and the results are also shown in Table 1.

Further, a film having a thickness of about 5 μm was prepared using the adhesive used here as a dope solution, and the absorption spectrum of the colored layer was measured. From the obtained absorption spectrum,
Absorbance A at 450 nm, Absorbance B at 500 nm, Absorbance C at 550 nm, and 65
The ratio of the absorbance E at 0 nm to the absorbance D at a wavelength of 600 nm was determined, and the results in Table 2 were obtained.

Example 2 20 g of a 5% aqueous solution of completely saponified polyvinyl alcohol
Then, the same test as in Example 1 was conducted except that 40 mg of a dye “Nippon Brilliant Violet BK conc.” Manufactured by Sumitomo Chemical Co., Ltd. different from that in Example 1 was dissolved and used as an adhesive. The results are shown in Tables 1 and 2.

Comparative Example 1 20 g of a 5% aqueous solution of completely saponified polyvinyl alcohol
The same test as in Example 1 was performed except that 60 mg of a dye "Sumifix Brilliant Blue R" manufactured by Sumitomo Chemical Co., Ltd., which was different from that of Example 1, was dissolved and used as an adhesive. The results are shown in Tables 1 and 2.

Comparative Example 2 To 20 g of a 5% aqueous solution of completely saponified polyvinyl alcohol,
The same test as in Example 2 was performed except that 60 mg of the same dye as in Example 2 was dissolved and used as an adhesive. The results are shown in Table 1. The relative absorbance at each wavelength of the film obtained from the adhesive was substantially the same as that in Example 2, and therefore, the description in Table 2 was omitted.

[0048]

[Table 1] Optical properties of polarizing plate 例 Example No. Ty K value Py flat row color phase Cartesian color phase (%) - (%) L * a * b * L * a * b * ━━━━━━━━━━━━━━━━━━━━━━対 照 Control 42.72 − 99.98 66.90 -1.59 6.65 0.05 0.09 0.04 ━━━━━━━━━━━━━ ────────── Example 1 40.28 2.44 99.97 63.72 -0.03 1.88 0.08 0.14 -0.03 Example 2 40.06 2.66 100 63.43 0.69 3.59 0.01 0.12 -0.05 ─────────────比較 Comparative Example 1 41.56 1.16 100 65.39 -2.05 5.63 0.01 0.15 -0.09 Comparative Example 2 39.13 3.59 100 62.21 1.88 1.45 0.01 0.07 -0.01 ━ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[0049]

[Table 2]

(Footnote of Table 2) A: Absorbance at 450 nm, B: Absorbance at 500 nm, C: Absorbance at 550 nm, D: Absorbance at 600 nm, E: Absorbance at 650 nm.

As can be seen from the above examples, the colored layers used in Examples 1 and 2 have all the absorption spectra satisfying the relations of the above formulas (I) to (IV). The parallel hue of the obtained polarizing plate is more neutral gray than that of the control polarizing plate having no coloring layer. On the other hand, the absorption spectrum of the colored layer used in Comparative Example 1 satisfied the relationship of the formulas (I) to (III), but did not satisfy the relationship of the formula (IV). The polarizing plate was compared with the polarizing plate of the comparative example having no coloring layer,
The change in parallel hue was small, far from neutral gray. On the other hand, when the amount of the dye is increased as in Comparative Example 2, the single transmittance is lower than 40%, and the white display of the liquid crystal display device is darkened.

[0052]

The polarizing plate of the present invention has a parallel hue approaching neutral gray, and has both a high degree of polarization, which is an advantage of a polarizing plate having no coloring layer, and an orthogonal hue of neutral gray. Therefore, when this polarizing plate is applied to a liquid crystal display device, there is no coloring of white display, high contrast, and black display becomes neutral gray, and good visibility can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H049 BA02 BA27 BB33 BB43 BB51 BB66 BC03 BC22 2H091 FA08X FA08Z FB02 FB12 FB13 FD06 LA17 LA20

Claims (8)

[Claims] 1. A polarizing plate comprising a protective film laminated on at least one surface of a polarizing film via an adhesive layer,
The a ^* and b ^* of the orthogonal hues measured based on JIS Z 8729 are −5.0 ≦ a ^* ≦ 10 and −10 ≦ b ^* ≦ 1.0, respectively, when the single transmittance is 40% or more. A ^* and b ^* of the parallel hues are respectively in the range of −4.0 ≦ a ^* ≦ 4.0 and −1.0 ≦ b ^* ≦ 5.5, and the polarizing plate is Any of the constituent layers has an absorbance at a wavelength of 450 nm as A, an absorbance at a wavelength of 500 nm as B, an absorbance at a wavelength of 550 nm as C,
D is the absorbance at a wavelength of 600 nm, and 650 nm
When the absorbance at E is E, the following formulas (I) to (IV) 0 ≦ A / D ≦ 0.3 (I) 0.1 ≦ B / D ≦ 0.7 (II) 0.5 ≦ C / D ≦ 1.4 (III) A polarizing plate having an absorption spectrum that satisfies all the relationships of 0 ≦ E / D ≦ 0.5 (IV). 2. The polarizing plate according to claim 1, wherein the layer having an absorption spectrum satisfying the relations of the formulas (I) to (IV) contains a coloring agent. 3. The coloring agent is CI Disperse Violet 26, CI Disperse Violet 28, C.I.
CI Disperse Violet 57, CI Disperse Violet 77, CI Acid Violet 48
3. The polarizing plate according to claim 2, wherein the polarizing plate is selected from C.I. 4. The colorant is CI Direct Violet.
9. The polarizing plate according to claim 3, wherein 5. The polarizing plate according to claim 2, wherein the adhesive layer contains a coloring agent. 6. A single transmittance T ₁ (%) of a polarizing plate having a layer containing a colorant, and a single transmittance T ₀ (%) of a polarizing plate having the same configuration except that the colorant is not included. From the following formula (V
I) The K value obtained by K = T ₀ −T ₁ (VI) is 0.05 to 3.
6. The polarizing plate according to any one of items 1 to 5, 7. A polarizing plate having a degree of polarization of 99% or more.
The polarizing plate according to any one of the above. 8. When a protective film is laminated on at least one surface of a polarizing film via an adhesive layer to produce a polarizing plate, any of the layers constituting the polarizing plate has a wavelength of 450.
When the absorbance at nm is A, the absorbance at 500 nm is B, the absorbance at 550 nm is C, the absorbance at 600 nm is D, and the absorbance at 650 nm is E, the following formulas (I) to (IV) 0 ≦ A /D≦0.3 (I) 0.1 ≦ B / D ≦ 0.7 (II) 0.5 ≦ C / D ≦ 1.4 (III) 0 ≦ E / D ≦ 0.5 (IV) A method for producing a polarizing plate, comprising adding a coloring agent to the layer so as to show an absorption spectrum satisfying all the relations.