TW201502210A - Polarization element and polarization plate for a display device comprising a blue light-emitting element - Google Patents

Abstract

The present invention relates to a polarizing element and a polarizing plate, which can improve contrast and enhance color display characteristics in an organic electroluminescent display device. A substrate having a polarizing function and containing an azo compound is controlled such that the substrate alone has a transmittance of 45% to 60%, the average transmittance of 440-nm to 500-nm wavelengths for one substrate is 50% or more, and the average transmittance of 550-nm to 650-nm wavelengths as obtained by measuring two substrates arranged such that the absorption axis directions thereof are orthogonal to one another is 10% or less.

Description

Polarizing element or polarizing plate for display device having blue light-emitting elements

The present invention relates to a polarizing element for an organic electroluminescence or a polarizing plate.

The polarizing element is usually produced by adsorbing an iodine or a dichroic dye which is a dichroic dye to a polyvinyl alcohol resin film. A protective film containing triacetyl cellulose or the like is bonded to at least one surface of the polarizing element via an adhesive layer to form a polarizing plate, which is used in a liquid crystal display device or the like. A polarizing plate using iodine as a dichroic dye is called an iodine-based polarizing plate, and a polarizing plate using a dichroic dye as a dichroic dye is called a dye-based polarizing plate. Among these, the dye-based polarizing plate has characteristics of high heat resistance, high moist heat durability, high stability, and high selectivity based on blending colors, and on the other hand, polarizing plates having the same degree of polarization Compared with the iodine-based polarizing plate, there is a problem that the transmittance is low, that is, the contrast is low. Therefore, it is expected to maintain high durability, various color selectivity, and higher transmittance, and high polarization characteristics.

In recent years, as disclosed in Patent Document 1 and Patent Document 2, a polarizing plate having a phase difference plate of 1/4 λ (1/4 wavelength with respect to 550 nm) having a phase difference of 120 nm to 150 nm, or a polarizing plate is bonded to a polarizing plate. A film in which a 1/4 λ phase difference plate having a phase difference of 120 nm to 150 nm and a phase difference plate having a phase difference of 260 nm to 290 nm of 1/2 λ (1/2 wavelength with respect to 550 nm) are bonded to a liquid crystal display device Also used in organic electroluminescent display devices Next, referred to as OLED). The OLED is displayed by self-illumination, but an electrode or the like is provided in the display device. When external light is incident on the device, reflected light is generated to lower the display contrast. In order to reduce the contrast reduction caused by the outer light of the OLED, a 1/4 λ phase difference plate is used to form a circular polarizing plate, thereby being used for antireflection in the OLED.

However, the polarizing plate which is generally used for OLEDs is white when the absorption axes of the two polarizing plates are arranged in parallel, in the same manner as the polarizing plate used for a liquid crystal display device such as a television or a mobile phone which requires high contrast. When the absorption axes of the polarizing plates are arranged orthogonally, an iodine-based polarizing plate having a high degree of polarization is formed in black. However, since such an iodine-based polarizing plate has a transmittance of 35% to 44%, there is a problem that the brightness is largely lowered. Further, since a large amount of light of 400 nm to 500 nm which is a short-wavelength side of visible light is absorbed, as in the OLEDs described in Patent Document 3 and Patent Document 4, the blue light-emitting efficiency of the OLED having a strong light emission near 460 nm is lowered. Therefore, the brightness is lowered and the display of color is lacking. In view of the problem that the brightness is greatly reduced, it is considered to use an iodine-based polarizing plate having a transmittance of 45% to 60% to prevent a decrease in brightness, but the durability of the iodine-based polarizing plate is poor, so that it may be caused by long-term use. The brightness is reduced and there is a clear lack of reliability.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-311239

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-27043

[Patent Document 3] Japanese Patent No. 4970934

[Patent Document 4] WO2012/128081

[Patent Document 5] Japanese Patent No. 4815149

[Non-patent literature]

[Non-Patent Document 1] Application of Functional Colorings First Printing Release, CMC Co., Ltd., published by Jiang Zhenghao, P98~100

[Non-Patent Document 2] Dye Chemistry, Hosoda Fumi, Tech Report Hall

In order to solve such a problem, Patent Document 5 discloses an organic EL (Electroluminescence) display technology for OLEDs, which absorbs light having a higher light efficiency and improves a band having a lower light efficiency. The transmittance of light reduces the polarization efficiency and improves the luminous efficiency, while preventing the contrast ratio of light and dark caused by light reflection. However, in this method, only the polarizing plate having the largest absorption at 500 nm to 600 nm in the range of high visibility is disclosed, and if the transmittance is adjusted only, the improvement in contrast and the display property of color are lacking. Further, if only a polarizing plate of only 500 nm to 600 nm is used, the improvement in contrast is insufficient. Further, Patent Document 5 does not describe the specific transmittance or the degree of polarization of the polarizing plate used and the transmittance of each wavelength.

When the luminous intensity of each wavelength of the OLED described in Patent Document 3 and Patent Document 4 is confirmed, it indicates light emission as shown in FIG. 1 . The luminescence intensity of the OLED shown in Fig. 1 is measured by using a spectroradiometer (Spectro-Radiometer USR-40, manufactured by Ushio Electric Co., Ltd.) and converting the highest luminescence intensity to 100.

Regarding the luminescence of the OLED, the luminescence centered on 460 nm is luminescence by the blue luminescent material, and the luminescence centered on 590 nm is luminescence obtained by fluorescence conversion of the blue luminescence by the phosphor. The method of the OLED is called a color conversion mode and is one of the ways of OLED. However, this method has a problem that the purity of the blue color is still poor, and further, if the external light is incident on the OLED, the phosphor emits light to lower the contrast. The contrast reduction caused by the external light is stronger when the external light is stronger, and the polarizing element or the polarized light must be controlled in order to suppress the light emission of the phosphor caused by the external light to improve the color purity of the blue luminous body and improve the luminous efficiency. The transmittance at each wavelength of the board. For a display device having a blue self-luminous element, it is necessary to design a polarizing element or a polarizing plate suitable for the same.

Further, it is understood that if external light is incident on the OLEDs of Patent Document 3 and Patent Document 4, the reflected light intensity as shown in FIG. 2 is obtained. The reflected light intensity of the OLED shown in Figure 2 is based on splitting The photometer U-4100 (manufactured by Hitachi, Ltd.) was measured, and the highest reflected light intensity was set to 100 and converted.

As shown in FIG. 2, it can be seen that the reflected light caused by the outer boundary light of the OLED exhibits a strong reflection at 500 nm to 600 nm. The stronger the reflection of the external light, the greater the influence on the display device. Since a transparent electrode of ITO (Indium Tin Oxide) for OLED is used, it is considered that such reflected light has an influence due to reflection thereof.

Therefore, for the OLED, it is required to control the reflected light from 500 nm to 650 nm from the external light without hindering the light emission of 440 nm to 500 nm centered at 460 nm, that is, for the polarizing element or the polarizing plate thereof, the individual body transmittance is required to be high and durable. The transmittance is higher, and the transmittance is higher at 440 nm to 500 nm, and the polarization is higher at 500 nm to 650 nm, especially at 550 nm to 650 nm.

The present inventors have made an effort to solve the above problems, and as a result, it has been newly found that a polarizing element or a polarizing plate faces a display device having a blue self-luminous element, which not only improves the contrast of the OLED but also improves the expression of color, the polarizing element or the polarized light. The plate is characterized in that it is a polarizing element comprising a substrate having an azo compound and having a polarizing function, and the transmittance of the substrate alone is 45% to 60%, and the transmittance of each wavelength of one substrate is The average transmittance of 440 nm to 500 nm is 50% or more, and the average transmittance of 550 nm to 650 nm in the transmittance of each wavelength obtained by measuring two substrates with respect to the absorption axis direction is 10% or less.

That is, the present invention relates to the following: "(1) A polarizing element comprising a substrate having an azo compound and having a polarizing function, and a transmittance of one of the substrates is 45% to 60%, and an average transmittance of 440 nm to 500 nm is 50% or more, and an average transmittance of 550 nm to 650 nm obtained by measuring two substrates perpendicular to the absorption axis direction is 10% or less; The polarizing element according to (1), wherein the substrate having an azo compound and having a polarizing function has an average transmittance of 440 nm to 500 nm obtained by measuring two substrates perpendicular to the absorption axis direction. 15% or more, the average transmittance of 550 nm to 650 nm of the substrate is 40% or more; (3) The polarizing element of (1) or (2), which has an azo compound and has a polarizing function. The average transmittance of 500 nm to 550 nm obtained by measuring two substrates perpendicular to the absorption axis direction is 20% or less, and the average transmittance of 500 nm to 550 nm of one substrate is 45%. (4) The polarizing element according to any one of claims 1 to 3, which has a degree of polarization of 6 (5) The polarizing element according to any one of claims 1 to 4, wherein at least one of the azo compounds contained in the substrate contains the azo compound represented by the formula (1) in the form of a free acid. ,

(A ₁ represents a phenyl group or a naphthyl group having a substituent, R ₁ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, and X ₁ represents a benzene which may have a substituent (6) The polarizing element according to any one of (1) to (4), wherein at least one of the azo compounds contained in the substrate contains the formula represented by the formula (2) in the form of a free acid. Azo compound,

(A ₂ represents a phenyl group having a substituent, and R ₂ to R ₅ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, and X ₂ represents a substitutable group. A phenylamino group, wherein R ₂ to R _{5 are} not satisfied, and all of them are a lower alkoxy group; (7) The polarizing element according to any one of (1) to (4), wherein At least one of the azo compounds contained contains the azo compound represented by the formula (3) in the form of a free acid,

(A ₃ represents a nitro group or an amine group, and R ₆ and R ₇ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, and X ₃ represents a substituent group; (8) The polarizing element according to any one of (1) to (7), wherein the two substrates are orthogonal to each other with respect to the absorption axis direction, and the measurement is performed at 500 nm to 550 nm. The average transmittance is 15% or less, the average transmittance of 440 nm to 500 nm of one substrate is 60% or more, and the average transmittance of 500 nm to 550 nm is 45% or more; (9) as in (1) to (8) In any one of the polarizing elements, at least one of the azo compounds contained in the substrate contains at least one of the azo compounds represented by the formulae (1) to (3), and is contained in the form of a free acid. (4) the azo compound represented,

(A ₄ represents a phenyl group or a naphthyl group having a substituent, and R ₈ or R ₉ each independently represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, or a lower alkoxy group having a sulfo group, X ₄ An amine group which may have a substituent, a benzhydrylamino group which may have a substituent, a phenylamine group which may have a substituent, a phenylazo group which may have a substituent, and a naphthalene which may have a substituent (10) The polarizing element according to (9), wherein X ₄ of the formula (4) is a phenylamine group which may have a substituent; (11) the polarizing element of (9) or (10), wherein A of formula (4) with ₄ of the phenyl substituent group; (12) (1) to (8) of the polarizing element according to any of the azo compound contained in the base material comprising at least one of the formula ( 1) at least one of the azo compounds represented by the formula (3), and together with the azo compound represented by the formula (5) in the form of a free acid,

(wherein R ₁₀ and R ₁₁ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, a lower alkoxy group having a sulfo group, a carbonyl group or a phenyl group or a naphthyl group having a halogen atom); (13) The polarizing element according to (12), wherein R ₁₀ and R _{11 of the} formula (5) are each independently a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, a lower alkoxy group having a sulfo group, or a carbonyl group. Or a phenyl group having a halogen atom; (14) The polarizing element according to (13), wherein R ₁₀ and R ₁₁ each independently independently have at least one substituent which is a methoxy group, and further the other substituent is a sulfo group or a carbonyl group; The polarizing element according to any one of (5) or (8), wherein R ₁ of the formula (1) is a methyl group or a methoxy group; (16) as (5) or (8) to ( 15) any one of the polarizing element, A in formula (1) a phenyl having ₁ substituent of the group; (17) (6) or (8) to (14) of any one polarizing element, wherein The polarizing element of any one of (6), (8) to (14) or (17), wherein the formula (2) is at least one of R ₄ or R ₅ ; ) of the R ₂ or R ₃ is at least one is methoxy; (19) (6), (8) to (15), one of the polarizing element (17) or (18) any , A wherein formula (2) ₂ of the phenyl group having a substituent; (20) (7) to (15) of any one of the polarizing element, R of formula (3) of at least ₆ and R ₇ of a The polarizing element of any one of (7) to (15) or (20), wherein R ₆ and R ₇ of the formula (3) are a methoxy group; (22) as The polarizing element according to any one of (1) to (22), wherein the substrate comprises a polyvinyl alcohol-based resin film, and (23) a polarizing plate, which is a polarizing element according to any one of (1) to (22) (24) The polarizing element according to any one of (1) to (22) or the polarizing plate of (23), which is provided with a phase having a phase difference of 120 nm to 150 nm. (25) An organic electroluminescence display device using the polarizing element of any one of (1) to (22) or the polarizing plate of (23) or (24).

The present invention relates to a polarizing element or a polarizing plate which can improve contrast and improve display of color in a display device having a blue self-luminous element, particularly an OLED.

Figure 1 shows the luminous intensity of each wavelength of an OLED.

Fig. 2 shows the intensity of reflected light when external light is incident on the OLED.

In Fig. 3, the first Y-axis indicates the transmittance of the polarizing plate of Example 2, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity was converted to 100 in Example 2.

In Fig. 4, the first Y-axis indicates the transmittance of the polarizing plate of Example 3, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity was converted to 100 in Example 3.

In Fig. 5, the first Y-axis indicates the transmittance of the polarizing plate of Example 6, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity was converted to 100 in Example 6.

In Fig. 6, the first Y-axis indicates the transmittance of the polarizing plate of Example 7, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity was converted to 100 in Example 7.

In Fig. 7, the first Y-axis indicates the transmittance of the polarizing plate of Example 8, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity was converted to 100 in Example 8.

In Fig. 8, the first Y-axis represents the transmittance of the polarizing plate of Comparative Example 1, and the second Y-axis represents the comparison. The luminous intensity from the OLED display device in the case where the highest intensity was converted to 100 in Example 1.

The present invention relates to a polarizing element or a polarizing plate in a display device having a blue self-luminous element, particularly an OLED, characterized in that it is a polarizing element comprising a substrate having an azo compound and having a polarizing function, and The transmittance of the individual body is 45% to 60%, and the average transmittance of 440 nm to 500 nm in the transmittance of each of the substrates is 50% or more, so that the two substrates are orthogonal to the absorption axis direction. The average transmittance of 550 nm to 650 nm obtained by the measurement was 10% or less.

The substrate refers to a film formed of a hydrophilic polymer containing an azo compound. The hydrophilic polymer is not particularly limited, and examples thereof include a polyvinyl alcohol resin, an amylose resin, a starch resin, a cellulose resin, and a polyacrylate resin. In the case of containing an azo compound, it is preferably a resin containing a polyvinyl alcohol-based resin and a derivative thereof in terms of workability, dyeability, crosslinkability, and the like. The polarizing element or the polarizing plate can be produced by forming the resin into a film form, containing the azo compound of the present invention and a formulation thereof, and applying an alignment treatment such as stretching.

The azo compound used in the present invention can be generally used as a dichroic dye, and more preferably a dichroic one. In this case, the dichroic dye represented by the azo compound is, for example, in addition to the azo compound shown in Non-Patent Document 1, and may be exemplified by CI Direct Yellow 12, CI Direct Yellow 28, and CI Direct Yellow. 44, CI direct orange 26, CI direct orange 39, CI direct orange 107, CI direct red 2, CI direct red 31, CI direct red 79, CI direct red 81, CI direct red 247, CI direct green 80, CI direct green An organic dye or the like described in JP-A-2001-33627, JP-A-2002-296417, and JP-A-60-156759. These dichroic dyes may be exemplified by an alkali metal salt (for example, a Na salt, a K salt, or a Li salt), an ammonium salt, or an amine salt in addition to the free acid. In addition, the dichroic dye is not limited to these, and can be exemplified Dichromatic dyes.

Adjusting the content of the dichroic dye containing the azo compound in the substrate, and adjusting the transmittance to be 45% to 60% of the substrate alone to have a polarizing function, 1 substrate The average transmittance of 440 nm to 500 nm in the transmittance of each wavelength is 50% or more, and the average transmittance of 550 nm to 650 nm in the transmittance of each wavelength obtained by measuring the two substrates with respect to the absorption axis direction is orthogonal. The rate is 10% or less, whereby the polarizing element or the polarizing plate of the invention of the present invention can be obtained. Here, the average transmittance in the present invention means an average value of each transmittance obtained by measuring every 5 nm between the wavelength and the wavelength shown. Specifically, for example, an average value of 440 nm to 500 nm represents an average value of transmittances of 440 nm, 445 nm, 450 nm, 460 nm, 465 nm, 470 nm, 475 nm, 480 nm, 485 nm, 490 nm, 495 nm, and 500 nm. The transmittance of the substrate alone affects the luminous efficiency of the light emitted from the OLED, and therefore it is preferred to have a high transmittance. The transmittance of each wavelength obtained by measuring the two substrates with respect to the absorption axis direction is preferably lower in order to reduce the reflected light when the external light is incident, and the average transmittance is from 440 nm to 500 nm. In order to improve the blue light-emitting efficiency with respect to the transmittance of each wavelength obtained by orthogonalizing the absorption axis direction, it is preferable that even if it is an OLED display device, there is no factor of light emission due to external light, and even if it is orthogonal Transmission also has a high transmission rate. The transmittance as the substrate alone is preferably 45% to 55%. If the transmittance exceeds 60%, the polarizing performance is remarkably lowered, which is not preferable. As the degree of polarization at this time, as long as it has 60% or more, the contrast of the OLED can be suppressed from decreasing, and it is preferably 70% or more, and more preferably 75% or more. In addition, it is preferable that the average transmittance of 440 nm to 500 nm in the transmittance of each wavelength of one substrate is 60% or more, and the two substrates are orthogonal to the absorption axis direction. The average transmittance of 550 nm to 650 nm in the transmittance of each wavelength obtained by the measurement was 6% or less. Further, it is preferable that the average transmittance of 440 nm to 500 nm in the transmittance of each wavelength of one substrate is 65% or more, and the two substrates are orthogonal to the absorption axis direction. The average transmittance of 550 nm to 650 nm in the transmittance of each wavelength obtained by the measurement was 3% or less.

Further, in order to form a polarizing element suitable for an OLED, it is preferable that an average transmittance of 440 nm to 500 nm in a transmittance of each wavelength obtained by measuring two substrates perpendicular to the absorption axis direction is 15 % or more, the average transmittance of 550 nm to 650 nm in the transmittance of each of the substrates of the substrate is 40% or more, whereby the luminescence of 440 nm to 500 nm is not inhibited, and the phosphor of 550 nm to 650 nm is not hindered. The light-emitting efficiency is preferably such that the average transmittance of 440 nm to 500 nm in the transmittance of each wavelength obtained by measuring the two substrates with respect to the absorption axis direction is 30% or more, and one substrate is used. The average transmittance of 550 nm to 650 nm in the transmittance of each wavelength is 40% or more. Further, it is preferable that an average transmittance of 440 nm to 500 nm in a transmittance of each wavelength obtained by measuring two substrates with respect to the absorption axis direction being orthogonal to each other is 40% or more, and each of the wavelengths of the substrate is one wavelength. The average transmittance of 550 nm to 650 nm in the transmittance is 43% or more.

Further, in order to prevent the contrast of the OLED from being lowered due to the influence of external light, it is preferable that the transmittance of each wavelength obtained by measuring the two base materials as the polarizing elements perpendicular to the absorption axis direction is 500 nm. The average transmittance to 550 nm is 20% or less, and the average transmittance of 500 nm to 550 nm of one substrate is 45% or more. Thus, by controlling the polarized light of 500 nm to 550 nm, the decrease in contrast caused by external light can be suppressed.

More preferably, the polarizing element or the polarizing plate of the present invention can be obtained by containing at least one azo compound represented by the formula (1) as an azo compound contained in the substrate in the form of a free acid. Preferably, R ₁ is a methyl group or a methoxy group, and further preferably A ₁ is a phenyl group having a substituent. Further, the lower alkyl group of the present invention and the lower alkyl group of the lower alkoxy group have a carbon number of 1 to 3.

(A ₁ represents a phenyl group or a naphthyl group having a substituent, and R ₁ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, or a lower alkoxy group having a sulfo group, and X ₁ represents a substituent group; Phenylamino group)

More preferably, the polarizing element or the polarizing plate of the present invention can be obtained by containing at least one azo compound represented by the formula (2) as an azo compound contained in the substrate in the form of a free acid. Preferably, at least one of R ₄ or R ₅ of the formula (2) is a methoxy group, and more preferably at least one of R ₂ or R ₃ of the formula (2) is a methoxy group, and more preferably a formula ( 2) A ₂ is a phenyl group having a substituent.

(A ₂ represents a phenyl group having a substituent, and R ₂ to R ₅ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, and X ₂ represents a substitutable group. a phenylamino group, wherein R ₂ to R ₅ do not satisfy all of the lower alkoxy groups at the same time)

More preferably, the polarizing element or the polarizing plate of the present invention can be obtained by containing at least one azo compound represented by the formula (3) as an azo compound contained in the substrate in the form of a free acid. Preferably, at least one of R ₆ or R ₇ of the formula (3) is a methoxy group, more preferably R ₆ and R ₇ of the formula (3) are a methoxy group, and further preferably A ₃ is a nitro group.

(A ₃ represents a nitro group or an amine group, and R ₆ and R ₇ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, and X ₃ represents a substituent group; Phenylamino group)

Further, in order to improve the contrast of the OLED and improve the expression of color, it is more preferable to average the transmittance of each wavelength obtained by measuring two polarizing substrates perpendicular to the absorption axis direction in the wavelengths of 500 nm to 550 nm. The transmittance is 15% or less, and the average transmittance of 440 nm to 500 nm of one substrate is 60% or more, and the average transmittance of 500 nm to 550 nm is 45% or more.

Further, in order to obtain an average transmittance of 500 nm to 550 nm in a transmittance of each wavelength obtained by measuring two substrates having polarizations perpendicular to the absorption axis direction, the average transmittance of the substrate is 15% or less. A good polarizing element having an average transmittance of 440 nm to 500 nm of 60% or more and an average transmittance of 45% or more from 500 nm to 550 nm, in order to improve the contrast of the OLED and improve the expression of color, by including in the substrate At least one of the azo compounds contains any one of the azo compounds represented by the formula (1) to the formula (3), and together with at least one azo compound represented by the formula (4) in the form of a free acid, A better polarizing element can be obtained. Preferably, X ₄ of the formula (4) is a phenylamine group which may have a substituent, and more preferably A ₄ of the formula (4) is a phenyl group having a substituent, whereby a more favorable polarizing element can be obtained, and further It is preferred that R ₁ and R ₂ are hydrogen atoms, whereby a more favorable polarizing element can be obtained.

(A ₄ represents a phenyl group or a naphthyl group having a substituent, and R ₈ or R ₉ each independently represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, or a lower alkoxy group having a sulfo group, X ₄ An amine group which may have a substituent, a benzhydrylamino group which may have a substituent, a phenylamine group which may have a substituent, a phenylazo group which may have a substituent, and a naphthalene which may have a substituent Azolyl)

Further, in order to obtain an average transmittance of 500 nm to 550 nm obtained by measuring two substrates having polarization and being orthogonal to the absorption axis direction, an average transmittance of 440 nm to 500 nm of one substrate is obtained. a good polarizing element of 60% or more and an average transmittance of 45% or more from 500 nm to 550 nm, in order to improve contrast of the OLED and improve color expression by at least one kind of azo compound contained in the substrate Any one of the azo compounds represented by the formula (1) to the formula (3), and at least one azo compound represented by the formula (5) in the form of a free acid, can obtain a more favorable polarizing element. . As the azo compound of formula (5) is represented, the OLED in order to improve the color contrast and improve the performance of, preferably R _10, R ₁₁ are each independently a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, The lower alkoxy group having a sulfo group, a carbonyl group or a phenyl group having a halogen atom, and further preferably each of R ₁₀ and R ₁₁ independently of at least one substituent is a methoxy group, and further the other substituent is a sulfo group or a carbonyl group.

(wherein R ₁₀ and R ₁₁ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, a lower alkoxy group having a sulfo group, a carbonyl group, or a phenyl group or a naphthyl group having a halogen atom)

The method of obtaining the dye represented by the formula (1) is exemplified by the method described in JP-A-01-5623, and the like, but is not limited thereto.

Examples of the method of obtaining the dye represented by the formula (2) include those described in Japanese Patent No. 2622748, Japanese Patent No. 4825135, WO2007/148757, and WO2009/142192, but are not limited thereto.

The method of obtaining the dye represented by the formula (3) is, for example, the method described in Japanese Patent Application No. 2011-197600, but is not limited thereto.

As a method of obtaining the azo compound represented by the formula (4), Japanese Patent Laid-Open No. 2003-215338, Japanese Patent Laid-Open No. Hei 9-302250, Japanese Patent No. 3881175, Japanese Patent No. 4452237, Japanese Patent No. The method described in No. 4,662,853, etc., but is not limited to these.

The azo compound or a salt thereof represented by the formula (5) can be easily produced by coupling according to the usual method for producing an azo dye described in Non-Patent Document 2. In a case where R ₁₀ and R ₁₁ are a phenyl group having a substituent, for example, R ₁₀ and R ₁₁ are diazotized by an amine compound represented by the formula (6) by a known method. Alkaline coupling with N,N-bis(1-hydroxy-3-sulfo-6-naphthyl)amine (common name: di J acid) at 20 ° C gave a disazo compound. Next, the solution is evaporated to dryness or salted out to be filtered and dried, and pulverized and pulverized, whereby a compound of the formula (5) can be obtained.

(wherein, Ra, Rb, and Rc each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, a lower alkoxy group having a sulfo group, a carbonyl group, or a halogen atom)

In the A ₁ to A ₄ of the azo compound represented by the formula (1) to the formula (4), A ₃ represents a phenyl group or a naphthyl group having a substituent, and as a substituent thereof, a hydrogen atom, a lower alkyl group, and a lower group are represented. An alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, a carbonyl group. Preferred substituents for higher efficiency and high contrast of the OLED are preferably a sulfo group, a methyl group, a methoxy group or a carbonyl group. The number of substituents may be one or two or more. In the case of having two or more substituents, the combination of the substituents may have a plurality of the same substituents, and the combination is not limited, and may have a heterologous substituent. For example, one substituent may be selected as a sulfo group, and the other substituent may be a carbonyl group.

Next, a more specific example of the dye represented by the formula (1) is shown below in the form of a free acid.

[Compound Example 1]

[Compound Example 2]

[Compound Example 3]

[Compound Example 4]

[Compound Example 5]

[Chemistry 16]

Next, a more specific example of the azo compound represented by the formula (2) is shown below in the form of a free acid.

[Compound Example 6]

[Compound Example 7]

[Compound Example 8]

[Compound Example 9]

[Compound Example 10]

[Compound Example 11]

[Compound Example 12]

[Compound Example 13]

[Compound Example 14]

Next, a more specific example of the azo compound represented by the formula (3) is shown below in the form of a free acid.

[Compound Example 15]

[Compound Example 16]

[Compound Example 17]

[Compound Example 18]

[Compound Example 19]

[Compound Example 20]

[Compound Example 21]

[Compound Example 22]

[Compound Example 23]

Examples of the dyes represented by the formula (4) include, for example, CI Direct Red 81, CI Direct Red 117, CI Direct Red 127, Japanese Patent No. 3881175, and Japanese Patent No. 4034343. Nitrogen compounds.

Hereinafter, a specific example of the azo compound represented by the formula (4) will be represented by a free acid.

[Compound Example 24]

[Compound Example 25]

[Compound Example 26]

[Compound Example 27]

[Compound Example 28]

[Compound Example 29]

[Compound Example 30]

[Compound Example 31]

[Compound Example 32]

[Compound Example 33]

Hereinafter, a specific example of the azo compound represented by the formula (4) will be represented by a free acid.

[Compound Example 34]

[Compound Example 35]

[Compound Example 36]

[Compound Example 37]

[Compound Example 38]

[Compound Example 39]

[Compound Example 40]

[Compound Example 41]

[Compound Example 42]

Hereinafter, a method of producing a specific polarizing element will be described using a polyvinyl alcohol-based resin film as a substrate. The method for producing the polyvinyl alcohol-based resin is not particularly limited, and it can be produced by a known method. The production method can be obtained, for example, by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to the polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith may be exemplified. Examples of the other monomer copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 95 mol% or more. The polyvinyl alcohol-based resin may be further modified, and for example, an aldehyde-modified polyvinyl formal or polyvinyl acetal may be used. Further, the degree of polymerization of the polyvinyl alcohol-based resin means the viscosity average degree of polymerization, which can be determined by a method known in the art. The degree of polymerization of the polyvinyl alcohol-based resin is usually from about 1,000 to 10,000, preferably from about 1,500 to 6,000.

A film made of the polyvinyl alcohol-based resin was used as a green film. Polyvinyl alcohol The method of forming the resin film is not particularly limited, and a film can be formed by a known method. In this case, the polyvinyl alcohol-based resin film may contain glycerin, ethylene glycol, propylene glycol, or a low molecular weight polyethylene glycol as a plasticizer. The plasticizing dose is 5 to 20% by weight, preferably 8 to 15% by weight. The film thickness of the green film containing the polyvinyl alcohol-based resin is not particularly limited, and is, for example, about 5 to 150 μm, preferably about 10 to 100 μm.

The swelling step was carried out on the green film obtained by the above method. The swelling treatment is applied by immersing in a solution of 20 to 50 ° C for 30 seconds to 10 minutes. The solution is preferably water. The stretching ratio is preferably adjusted from 1.00 to 1.50 times, preferably from 1.10 to 1.35 times. In the case where the time for producing the polarizing film is shortened, since the dyeing is also performed during the dyeing treatment, the swelling treatment may be omitted.

The swelling step is carried out by immersing the polyvinyl alcohol resin film in a solution at 20 to 50 ° C for 30 seconds to 10 minutes. The solution is preferably water. In the case where the time for manufacturing the polarizing element is shortened, since the swelling is performed during the dyeing treatment of the dye, the swelling treatment may be omitted.

The dyeing step is carried out after the swelling step. In the dyeing step, impregnation may be carried out using an azo compound (commonly known as a dichroic dye) shown in Non-Patent Document 1 or the like. The step of impregnating the azo compound is a dyeing step because of the step of coloring the color. Here, as the azo compound, the dye described in Non-Patent Document 1 or the azo compound represented by Formula (1), Formula (2), Formula (3), Formula (4), Formula (5), or the like can be used. The polyvinyl alcohol film is adsorbed to the dye in the dyeing step, and impregnation is carried out. The dyeing step is not particularly limited as long as it is a method of adsorbing a dye on a polyvinyl alcohol film and impregnating it. For example, the dyeing step can be carried out by immersing the polyvinyl alcohol resin film in a solution containing an azo compound. The temperature of the solution in this step is preferably from 5 to 60 ° C, more preferably from 20 to 50 ° C, and particularly preferably from 35 to 50 ° C. The time of immersion in the solution can be appropriately adjusted, and it is preferably adjusted in 30 seconds to 20 minutes, more preferably 1 to 10 minutes. The dyeing method is preferably immersed in the solution, but it can also be carried out by coating the solution with a polyvinyl alcohol resin film. The solution containing the azo compound may contain hydrogen carbonate Sodium, sodium chloride, sodium sulfate, anhydrous sodium sulfate, sodium tripolyphosphate, etc. are used as dyeing assistants. The content thereof may be adjusted at any concentration depending on the time and temperature of dye dyeing, and is preferably 0 to 5% by weight, and more preferably 0.1 to 2% by weight, based on the respective contents. An azo compound of the dichroic dye described in Non-Patent Document 1 or an azo compound represented by the formula (1), the formula (2), the formula (3), the formula (4), the formula (5), or the like In addition to being used in the form of a free acid, it may also be a salt of the compound. Such a salt can also be used as an alkali metal salt such as a lithium salt, a sodium salt or a potassium salt, or an organic salt such as an ammonium salt or an alkylamine salt. It is preferably a sodium salt.

The washing step (hereinafter referred to as washing step 1) may be performed after the dyeing step and before proceeding to the next step. The washing step 1 is a step of washing the dye solvent adhering to the surface of the polyvinyl alcohol resin film in the dyeing step. By performing the washing step 1, it is possible to inhibit the dye from moving to the liquid to be treated next. Water is usually used in the washing step 1. The washing method is preferably immersed in the solution, but it may be washed by applying the solution to a polyvinyl alcohol resin film. The washing time is not particularly limited, and is preferably from 1 to 300 seconds, more preferably from 1 to 60 seconds. The temperature of the solvent in the washing step 1 must be a temperature at which the hydrophilic polymer is not dissolved. It is usually washed at 5 to 40 °C. However, since there is no problem in performance even without the step of the cleaning step 1, this step can be omitted.

The step of containing a crosslinking agent and/or a water resistant agent may be carried out after the dyeing step or the washing step 1. As the crosslinking agent, for example, a boron compound such as boric acid, borax or ammonium borate, a polyvalent aldehyde such as glyoxal or glutaraldehyde, a polyisocyanate compound such as a biuret type, an isocyanurate type or a block type can be used. A titanium compound such as titanium oxysulfate or the like, and ethylene glycol glycidyl ether or polyamine epichlorohydrin can also be used. Examples of the water resistance agent include peroxysuccinic acid, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerol diglycidyl ether, ammonium chloride or magnesium chloride, and the like. Boric acid. The step of containing a crosslinking agent and/or a water resistance agent is carried out using at least one or more crosslinking agents and/or water resistance agents as described above. The solvent at this time is preferably water, but is not limited. Regarding the solvent in the step of containing a crosslinking agent and/or a water resistance agent The concentration of the crosslinking agent and/or the water-resistant agent is preferably from 0.1 to 6.0% by weight, more preferably from 1.0 to 4.0% by weight, based on the boric acid. The solvent temperature in this step is preferably from 5 to 70 ° C, more preferably from 5 to 50 ° C. The method of allowing the polyvinyl alcohol resin film to contain a crosslinking agent and/or a water resistance agent is preferably immersed in the solution, or the solution may be applied or applied to a polyvinyl alcohol resin film. The processing time in this step is preferably from 30 seconds to 6 minutes, more preferably from 1 to 5 minutes. However, it is not necessary to contain a crosslinking agent and/or a water-resistant agent, and when it is intended to shorten the time, when the crosslinking treatment or the water resistance treatment is not required, the treatment step may be omitted.

After the dyeing step, the washing step 1, or the step of containing a crosslinking agent and/or a water-resistant agent, an extending step is performed. The extension step refers to a step of stretching a polyvinyl alcohol film on a uniaxial axis. The stretching method may be either a wet stretching method or a dry stretching method, and the stretching may be carried out by stretching at a stretching ratio of 3 times or more. It is preferred to carry out stretching at a stretching ratio of 3 times or more, preferably 5 times to 7 times.

In the case of the dry stretching method, when the extending heating medium is an air medium, it is preferred to extend the temperature of the air medium at a normal temperature of ~180 °C. Further, it is preferred to carry out the treatment in an environment having a humidity of 20 to 95% RH. Examples of the heating method include an inter-roller region stretching method, a roll heating stretching method, a pressure stretching method, and an infrared heating stretching method, and the stretching method is not limited. The extension step can be extended in one stage or by multi-stage extension of two stages or more.

In the case of the wet stretching method, stretching is carried out in water, a water-soluble organic solvent, or a mixed solution thereof. It is preferred to carry out the stretching treatment while immersing in a solution containing a crosslinking agent and/or a water-resistant agent. As the crosslinking agent, for example, a boron compound such as boric acid, borax or ammonium borate, a polyvalent aldehyde such as glyoxal or glutaraldehyde, a polyisocyanate compound such as a biuret type, an isocyanurate type or a block type can be used. A titanium-based compound such as titanyl sulfate or the like may be used, and ethylene glycol glycidyl ether or polyamine-epichlorohydrin may also be used. Examples of the water resistance agent include peroxysuccinic acid, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, and ethylene glycol. Diglycidyl ether, glycerol diglycidyl ether, ammonium chloride or magnesium chloride. The stretching is carried out in a solution containing at least one of the above-mentioned crosslinking agents and/or a water-resistant agent. The crosslinking agent is preferably boric acid. The concentration of the crosslinking agent and/or the water resistance agent in the stretching step is, for example, preferably from 0.5 to 15% by weight, more preferably from 2.0 to 8.0% by weight. The stretching ratio is preferably 2 to 8 times, more preferably 5 to 7 times. Preferably, the treatment is carried out at an extension temperature of 40 to 60 ° C, more preferably 45 to 58 ° C. The extension time is usually 30 seconds to 20 minutes, more preferably 2 to 5 minutes. The wet extension step can be carried out in one stage or by a multistage extension of two stages or more.

After the stretching step, the crosslinking agent and/or the water-resistant agent are precipitated or foreign matter adheres to the surface of the film, so that the step of washing the surface of the film (hereinafter referred to as "cleaning step 2") can be performed. The washing time is preferably from 1 second to 5 minutes. The washing method is preferably immersed in the washing solution, but can be washed by applying or applying the solution to a polyvinyl alcohol resin film. The washing treatment may be carried out in one stage, or the multi-stage treatment in two or more stages may be performed. The temperature of the solution in the washing step is not particularly limited and is usually 5 to 50 ° C, preferably 10 to 40 ° C.

Examples of the solvent used in the treatment step up to this include water, dimethyl hydrazine, N-methylpyrrolidone, methanol, ethanol, propanol, isopropanol, glycerin, ethylene glycol, and propylene glycol. An alcohol such as diethylene glycol, triethylene glycol, tetraethylene glycol or trimethylolpropane, or an amine such as ethylenediamine or diethyltriamine, but is not limited thereto. Further, a mixture of one or more of these solvents may be used. The best solvent is water.

After the stretching step or the washing step 2, a drying step of the film is carried out. The drying treatment can be carried out by natural drying, and in order to further improve the drying efficiency, the surface may be subjected to moisture removal by a roll or by an air knife, a water absorbing roll or the like, and/or air drying may be performed. The drying treatment temperature is preferably carried out at 20 to 100 ° C, more preferably at 60 to 100 ° C. The drying treatment time can be applied for 30 seconds to 20 minutes, preferably 5 to 10 minutes.

According to the above method, a polarizing element can be obtained, which is a substrate containing the azo compound of the present invention and having a polarizing function, and the substrate is transparent to the individual body. The average ratio of 550 nm to 650 nm obtained by measuring the average transmittance of 440 nm to 500 nm of one substrate is 50% or more, and the two substrates are orthogonal to the absorption axis direction. The transmittance is 10% or less.

The polarizing element obtained is made into a polarizing plate by providing a transparent protective layer on one or both sides. The transparent protective layer can be provided as a laminate layer based on a polymer coating layer or film. As the transparent polymer or film forming the transparent protective layer, a transparent polymer or film having high mechanical strength and good thermal stability is preferred. Examples of the substance used as the transparent protective layer include cellulose acetate resin such as triacetonitrile cellulose or diethyl cellulose, or a film thereof, acrylic resin or film thereof, polyvinyl chloride resin or film thereof, and nylon. Resin or film thereof, polyester resin or film thereof, polyarylate resin or film thereof, such as a cyclic polyolefin resin having a cyclic olefin as a monomer or a film thereof, polyethylene, polypropylene, having a ring system or a lowering The polyolefin of the olefin skeleton or a copolymer thereof, a main chain or a side chain thereof, a resin or a polymer of ruthenium and/or guanamine, or a film thereof. Further, a resin having a liquid crystal property or a film thereof may be provided as a transparent protective layer. The thickness of the protective film is, for example, about 0.5 to 200 μm. A polarizing plate is produced by providing one or more layers of the same or different kinds of resins or films on one side or on both sides.

An adhesive is required in order to bond the transparent protective layer to the polarizing element. The adhesive is not particularly limited, and is preferably a polyvinyl alcohol adhesive. Examples of the polyvinyl alcohol-based adhesive include, but are not limited to, Gohsenol NH-26 (manufactured by Nippon Synthetic Co., Ltd.) and Exceval RS-2117 (manufactured by Kuraray Co., Ltd.). A crosslinking agent and/or a water resistance agent may be added to the adhesive. As the polyvinyl alcohol adhesive, a maleic anhydride-isobutylene copolymer is used, and an adhesive mixed with a crosslinking agent may be used as needed. Examples of the maleic anhydride-isobutylene copolymer include: Isobam #18 (manufactured by Kuraray Co., Ltd.), Isobam #04 (manufactured by Kuraray Co., Ltd.), ammonia-modified Isobam #104 (manufactured by Kuraray Co., Ltd.), and ammonia reform. Isobam #110 (manufactured by Kuraray Co., Ltd.), Isobam #304 (manufactured by Kuraray Co., Ltd.), Isobam #310 (manufactured by Kuraray Co., Ltd.), and the like. The cross-linking agent at this time can use a water-soluble polyvalent epoxy compound. The water-soluble polyvalent epoxy compound is exemplified by, for example: DENACOL EX-521 (manufactured by Nagase Chemical Co., Ltd.), TETRAD-C (manufactured by Mitsui Gas Chemical Co., Ltd.), and the like. Further, as an adhesive other than the polyvinyl alcohol resin, a known adhesive such as an urethane type, an acrylic type or an epoxy type can also be used. Further, for the purpose of improving the adhesion of the adhesive or improving the water resistance, an additive such as a zinc compound, a chloride or an iodide may be contained at a concentration of about 0.1 to 10% by weight. There is no limitation on the additives. After the transparent protective layer is bonded by an adhesive, drying or heat treatment is performed at an appropriate temperature, whereby a polarizing plate is obtained.

The polarizing plate obtained may be provided to improve the viewing angle and/or improve the contrast on the surface of the protective layer or film which is not exposed later, for example, when it is attached to a display device such as an organic electroluminescence. Various functional layers, layers or films having brightness enhancement. When the polarizing plate is attached to the film or display device, it is preferred to use an adhesive.

The polarizing plate may have various known functional layers such as an antireflection layer, an antiglare layer, and a hard coat layer on the other surface, that is, the exposed surface of the protective layer or the film. In the case of producing the layer having various functionalities, a coating method is preferred, and the functional film may be bonded via an adhesive or an adhesive. Further, the various functional layers can be made into layers or films that control the phase difference. For the OLED display device, by affixing a phase difference plate of 120 nm to 150 nm, in particular, a 1/4 λ phase difference plate of about 555 nm, when external light is incident on the OLED, it can have an anti-reflection function.

According to the above method, a polarizing element and a polarizing plate are obtained, which are the substrate containing the azo compound of the present invention and having a polarizing function, and the transmittance of the substrate alone is 45% to 60%. The average transmittance of 440 nm to 500 nm of one substrate is 50% or more, and the average transmittance of 550 nm to 650 nm obtained by measuring two substrates with respect to the absorption axis direction is 10% or less. A display device having a color self-luminous element using the polarizing element or the polarizing plate of the present invention, particularly an OLED, has high reliability, long-term high contrast, and high color reproducibility.

The polarizing element or the polarizing plate of the present invention thus obtained may be provided with a protective layer or The functional layer, the support, and the like are used as effective polarizing elements or polarizing plates in a display device that emits blue light, for example, organic electroluminescence.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited thereto. Further, the evaluation of the transmittance shown in the examples was carried out as follows.

When the transmittance of one polarizing element or the polarizing plate is measured as the transmittance Ts, the transmittance of the two polarizing elements or the polarizing plates in which the absorption axis directions are the same is set as the parallel transmittance Tp. The transmittance of the two polarizing plates in such a manner that their absorption axes are orthogonal to each other is set to the orthogonal bit transmittance Tc.

The individual transmittance Ys is in the wavelength range of 400 nm to 700 nm, and the spectral transmittance τλ is obtained every specific wavelength interval dλ (here, 5 nm), and is calculated by the following formula (I). In the formula, Pλ represents a spectral distribution of a standard light (C light source), and yλ represents a color function of a 2 degree field of view.

The spectral transmittance τλ was measured using a spectrophotometer [manufactured by Hitachi, Ltd. "U-4100").

The degree of polarization ρy is obtained by the formula (II) based on the parallel bit transmittance Tp and the orthogonal bit transmittance Tc.

ρ y={(Tp-Tc)/(Tp+Tc)}1/2×100 (II)

Example 1

A polyvinyl alcohol film (VF-XS manufactured by Kuraray Co., Ltd.) having an average degree of polymerization of 2400 or more having a degree of saponification of 99% or more was immersed in warm water of 45 ° C for 2 minutes, and the stretching ratio was set to 1.30 times by a swelling treatment. The swelled film was immersed in an aqueous solution containing 1500 parts by weight of water, 1.5 parts by weight of sodium tripolyphosphate, and 0.15 parts by weight of the dye described in Example 2 of JP-A-09-132726, and dyed. The dyed film was stretched to 5.0 times on one side and extended in an aqueous solution containing boric acid 30.0 g/L at 50 ° C for 5 minutes. While maintaining the stretched state of the film obtained by the boric acid treatment, it was subjected to a water washing treatment for 30 seconds in water at 30 ° C, and the obtained film was dried at 70 ° C for 9 minutes to obtain a transmittance of the present invention. 50% polarizing element. The polarizing element obtained by drying and the alkali-treated triacetyl cellulose film (TD-80U manufactured by Fujifilm Co., Ltd.) were laminated using a polyvinyl alcohol-based adhesive to obtain a polarizing plate. When the obtained polarizing plate was subjected to an endurance test for 700 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% RH, no change in transmittance and polarization degree was observed.

Example 2

0.15 parts by weight of the dye described in Example 2 of the Japanese Patent Application Laid-Open No. Hei 09-132726, which is described in the first embodiment, is replaced by 0.15 parts by weight of the dye described in Example 3 of Japanese Patent Laid-Open No. Hei 10-259311. A polarizing element and a polarizing plate were produced in the same manner to prepare a measurement sample. When the obtained polarizing plate was subjected to an endurance test for 700 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% RH, no change in transmittance and polarization degree was observed.

Example 3

The content of 0.15 parts by weight of the dye described in Example 2 of the Japanese Patent Publication No. 09-132726, which is described in the first embodiment, is described in the second embodiment of the Japanese Patent Application Laid-Open No. Hei 2-309302. A polarizing element and a polarizing plate were produced in the same manner except that the amount of the dye was 0.1 parts by weight, and a measurement sample was prepared. To obtain the polarizing plate at a temperature When the durability test was performed for 700 hours in an environment of 85 ° C and a relative humidity of 85% RH, no change in transmittance and polarization degree was observed.

Example 4

0.15 parts by weight of the dye described in Example 2 of JP-A-H09-132726, which is described in the first embodiment, is replaced by the one described in Example 1 of Japanese Patent Laid-Open No. 01-5623 having the structure of the formula (1). A polarizing element and a polarizing plate were produced in the same manner except that the amount of the nitrogen compound was 0.2 parts by weight, and a measurement sample was prepared. When the obtained polarizing plate was subjected to an endurance test for 700 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% RH, no change in transmittance and polarization degree was observed.

Example 5

0.15 parts by weight of the dye described in Example 2 of the Japanese Patent Laid-Open No. 09-132726, which is described in the first embodiment, is replaced by the compound described in the first example of the compound of the International Patent Publication No. WO 2013/035752 A1 having the structure of the formula (3). A polarizing element and a polarizing plate were produced in the same manner except that the amount of the nitrogen compound was 0.2 parts by weight, and a measurement sample was prepared. When the obtained polarizing plate was subjected to an endurance test for 700 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% RH, no change in transmittance and polarization degree was observed.

Example 6

The azo compound 0.098 described in Example 1 of Japanese Patent No. 2622748, which has the structure of the formula (2), was replaced by 0.15 parts by weight of the dye described in Example 2 of JP-A-H09-132726. A polarizing element and a polarizing plate were produced in the same manner except for the parts by weight to prepare a measurement sample. When the obtained polarizing plate was subjected to an endurance test for 700 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% RH, no change in transmittance and polarization degree was observed.

Example 7

The dyeing liquid containing 0.15 parts by weight of the dye described in Example 2 of the Japanese Patent Laid-Open No. 09-132726 of the first embodiment is replaced with Japan having the structure of the formula (2). 0.098 parts by weight of the azo compound described in Example 1 of the patent No. 2622748, and 0.7 parts by weight of the dye of the formula (16) described in Example A-3 of Japanese Patent Application No. 2012-041024 having the structure of the formula (5) A polarizing element and a polarizing plate were produced in the same manner except for the dyeing liquid, and a measurement sample was prepared. When the obtained polarizing plate was subjected to an endurance test for 700 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% RH, no change in transmittance and polarization degree was observed.

Example 8

The dyeing liquid containing 0.15 parts by weight of the dye described in Example 2 of the Japanese Patent Laid-Open Publication No. Hei 09-132726 of the first embodiment is replaced with the first embodiment of the Japanese Patent No. 2622748 having the structure of the formula (2). A polarizing element and a polarizing plate were produced in the same manner except that 0.098 parts by weight of the azo compound described above and 0.7 parts by weight of the dye of the compound No. 1 of Japanese Patent No. 4013344 of the structure of the formula (4) were used. , a test sample was prepared. When the obtained polarizing plate was subjected to an endurance test for 700 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% RH, no change in transmittance and polarization degree was observed.

Comparative example 1

An iodine-based polarizing plate containing no dichroic dye was prepared according to the formulation of Comparative Example 1 of JP-A-2008-065222, and a polarizing plate having a transmittance of about 50% was produced, except that it was the same as in Example 1. A measurement sample was prepared in the same manner. When the obtained polarizing plate was subjected to an endurance test for 700 hours in an environment of a temperature of 85 ° C and a relative humidity of 85% RH, the individual body transmittance was changed to 88%, and the degree of polarization disappeared.

Table 1 shows the transmittance (Ys) and the degree of polarization (ρy) of the substrate alone of Examples 1 to 8 and Comparative Example 1, and 440 nm to 500 nm obtained by measurement at intervals of 5 nm (hereinafter, Ave440-500 is omitted). The average transmittance (Ts) of the individual body and the average transmittance (Tc) of each wavelength obtained by measuring the two substrates with respect to the absorption axis direction, and 500 nm to 550 nm measured at intervals of 5 nm. (hereinafter, Ave 500-550 is omitted) The average transmittance (Ts) of the individual bodies and the measurement of the two substrates with respect to the absorption axis direction are orthogonal. The average transmittance (Tc) of each wavelength obtained, the average transmittance (Ts) of 550 nm to 650 nm (hereinafter, omitted as Ave550-650) obtained by measuring at intervals of 5 nm, and the relative absorption of two substrates. The average transmittance (Tc) of each wavelength obtained by measuring the axial direction is orthogonal.

According to the results of Table 1, it is understood that a polarizing plate having a high Ts of 440 nm to 500 nm and a large difference between Ts and Tc of 550 nm to 650 nm is obtained, which is a substrate containing an azo compound and having a polarizing function of the present invention, and The transmittance of the substrate alone is 45% to 60%, and the average transmittance of 440 nm to 500 nm of one substrate is 50% or more, and the two substrates obtained by measurement are orthogonal to the absorption axis direction. The average transmittance of 550 nm to 650 nm is 10% or less.

Next, the 1/4 λ phase difference plate having a phase difference of 138 nm obtained by stretching the polycarbonate was attached to the absorption axes of the extension axis and the polarizing plate at 45° to Examples 1 to 8, and Comparative Example 1 In the obtained polarizing plate, the obtained polarizing plate was bonded to an OLED display device via an adhesive (PTR-3000, manufactured by Nippon Kayaku Co., Ltd.) to prepare a measurement sample. The xy color coordinates indicating the xy chromaticity diagram defined by CIE 1931 when the color purity of the OLED was measured using a color luminance meter (CS-200, manufactured by Konica Minolta Co., Ltd.) were measured. Use this by calculating the NTSC ratio (the color-to-space ratio of the TV standardized by the National Television System Committee) The ratio (%) indicates the color reproduction range at this time. The results of the xy color coordinates and the NTSC ratio when the color purity was measured are shown in Table 2.

Regarding the NTSC ratio, as the coordinates when the NTSC ratio is 100%, the red color coordinates are set to (0.67, 0.33), the green color coordinates are set to (0.21, 0.71), and the blue color coordinates are set to (0.14). , 0.08), and the area derived from the coordinate is calculated as 100%. The calculation method is calculated based on the formula (III).

NTSC ratio = (Rx × Gy + Gx × By + Bx × Ry - Ry × Gx - Gy × Bx - By × Rx) × 100 / 0.3164. . . Formula (III)

(The x coordinate in red measurement is expressed as Rx, the y coordinate in red measurement is represented as Ry, the x coordinate in green measurement is represented as Gx, the y coordinate in green measurement is represented as Gy, and the x coordinate in blue measurement) For Bx, the y coordinate of the blue measurement is expressed as By)

According to the results of Table 2, it is understood that the NTSC ratio is improved as compared with the case of using the prior iodine-based polarizing plate by providing the polarizing plate obtained according to the present invention to the OLED.

Next, an OLED in which the polarizing plate used in Example 6 was bonded to 1/4 λ was measured using a color luminance meter (CS-200, manufactured by Konica Minolta Co., Ltd.) under the conditions of an external light luminance of 500 cd/m ² . OLED brightness, calculate the contrast between white projection and black projection. The results are shown in Table 3. Furthermore, OLED-ON indicates the state when white light is emitted, and OLED-OFF indicates the state when black is displayed.

Next, an OLED in which the polarizing plate used in Example 6 was bonded to 1/4 λ was measured using a color luminance meter (CS-200, manufactured by Konica Minolta Co., Ltd.) under the condition of an external light luminance of 1500 cd/m ² . OLED brightness, calculate the contrast between white projection and black projection. The results are shown in Table 4.

Next, the OLED in which the polarizing plate used in Example 8 was bonded to 1/4 λ was measured using a color luminance meter (CS-200, manufactured by Konica Minolta Co., Ltd.) under the conditions of an external light luminance of 500 cd/m ² . OLED brightness, calculate the contrast between white projection and black projection. The results are shown in Table 5.

Next, an OLED in which the polarizing plate used in Example 8 was bonded to 1/4 λ was measured using a color luminance meter (CS-200, manufactured by Konica Minolta Co., Ltd.) under the condition of an external light luminance of 1500 cd/m ² . OLED brightness, calculate the contrast between white projection and black projection. The results are shown in Table 6.

Next, the OLED in which the polarizing plate used in Comparative Example 1 was bonded to 1/4 λ was measured using a color luminance meter (CS-200, manufactured by Konica Minolta Co., Ltd.) under the conditions of an external light luminance of 500 cd/m ² . OLED brightness, calculate the contrast between white projection and black projection. The results are shown in Table 7.

Next, an OLED in which the polarizing plate used in Comparative Example 1 was bonded to 1/4 λ was measured using a color luminance meter (CS-200, manufactured by Konica Minolta Co., Ltd.) under the condition of an external light luminance of 1500 cd/m ² . OLED brightness, calculate the contrast between white projection and black projection. The results are shown in Table 8.

As is clear from the results of Tables 3 to 8, it is understood that when the polarizing plates of Examples 1 to 8 are used, the contrast at the time of incidence of external light is increased by about 10 times, which is also effective for improving the contrast. when the case of using the polarizing plate of Comparative Example 1, not only a white light emission luminance of OLED when the projection of white decreases, and almost no time to improve the contrast of the 500cd / m ² or 1500cd / m ² of outside light and the like incident.

In Fig. 3, the first Y axis represents the transmittance of the polarizing plate of the second embodiment, and the second Y axis represents The luminous intensity from the OLED display device in the case where the highest intensity is converted to 100. According to the graph of FIG. 3, it can be seen that the polarizing plate of the present invention does not hinder the light emission of 440 nm to 500 nm, and the polarization degree of 550 nm to 650 nm is high, and the polarizing plate is characterized in that it contains an azo compound and has a polarizing function. The substrate has a transmittance of 45% to 60% of the substrate alone, and an average transmittance of 440 nm to 500 nm of one substrate is 50% or more, so that the two substrates are orthogonal to the absorption axis direction. The average transmittance of 550 nm to 650 nm obtained by the measurement was 10% or less.

In FIG. 4, the first Y-axis indicates the transmittance of the polarizing plate of Example 3, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity is converted to 100. According to the graph of FIG. 4, it can be seen that the polarizing plate of the present invention does not hinder the light emission of 440 nm to 500 nm, and the polarization degree of 550 nm to 650 nm is high, and the polarizing plate is characterized in that it contains an azo compound and has a polarizing function. The substrate has a transmittance of 45% to 60% of the substrate alone, and an average transmittance of 440 nm to 500 nm of one substrate is 50% or more, so that the two substrates are orthogonal to the absorption axis direction. The average transmittance of 550 nm to 650 nm obtained by the measurement was 10% or less.

In Fig. 5, the first Y-axis indicates the transmittance of the polarizing plate of Example 6, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity is converted to 100. According to the graph of FIG. 5, it can be seen that the polarizing plate of the present invention does not hinder the light emission of 440 nm to 500 nm, and the polarization degree of 550 nm to 650 nm is high, and the polarizing plate is characterized in that it contains an azo compound and has a polarizing function. The substrate has a transmittance of 45% to 60% of the substrate alone, and an average transmittance of 440 nm to 500 nm of one substrate is 50% or more, so that the two substrates are orthogonal to the absorption axis direction. The average transmittance of 550 nm to 650 nm obtained by the measurement was 10% or less.

In Fig. 6, the first Y-axis indicates the transmittance of the polarizing plate of Example 7, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity is converted to 100. According to the graph of FIG. 6, it is understood that the polarizing plate of the present invention does not hinder the light emission of 440 nm to 500 nm, and The polarizing plate has a high degree of polarization from 550 nm to 650 nm, and the polarizing plate is characterized in that it is a substrate containing an azo compound and having a polarizing function, and the transmittance of the substrate alone is 45% to 60%, 1 piece. The average transmittance of the substrate from 440 nm to 500 nm is 50% or more, and the average transmittance of 550 nm to 650 nm obtained by measuring two substrates with respect to the absorption axis direction is 10% or less.

In Fig. 7, the first Y-axis indicates the transmittance of the polarizing plate of Example 8, and the second Y-axis indicates the luminous intensity from the OLED display device in the case where the highest intensity is converted to 100. According to the graph of FIG. 7, it can be seen that the polarizing plate of the present invention does not hinder the light emission of 440 nm to 500 nm, and the polarizing degree of 550 nm to 650 nm is high, and the polarizing plate is characterized in that it contains an azo compound and has a polarizing function. The substrate has a transmittance of 45% to 60% of the substrate alone, and an average transmittance of 440 nm to 500 nm of one substrate is 50% or more, so that the two substrates are orthogonal to the absorption axis direction. The average transmittance of 550 nm to 650 nm obtained by the measurement was 10% or less.

In FIG. 8, the first Y-axis represents the transmittance of the polarizing plate of Comparative Example 1, and the second Y-axis represents the luminous intensity from the OLED display device in the case where the highest intensity is converted to 100. According to the graph of Fig. 8, it is understood that a polarizing plate having an average transmittance of 440 nm to 500 nm of 50% or less of one substrate is obtained. From the results of FIG. 8, it is understood that the polarizing plate of Comparative Example 1 hinders light emission of 440 nm to 500 nm, lowers the brightness of the OLED, and does not sufficiently suppress the light emission of the phosphor caused by external light, and thus the contrast is also lowered.

According to the results of Tables 1 to 8 and 3 to 8 of the polarizing plates of Examples 1 to 8 and Comparative Example 1, it can be seen that the following polarizing element or polarizing plate has high durability, and the color expression of the OLED can be improved. To improve the contrast of external light incident, the polarizing element is a substrate containing an azo compound and having a polarizing function in the present case, and the transmittance of the substrate alone is 45% to 60%, and the transmittance of the substrate is 440 nm. The average transmittance at 500 nm is 50% or more, and the average transmittance of 550 nm to 650 nm obtained by measuring two substrates with respect to the absorption axis direction is 10% or less. Having a polarizing element or a polarizing plate using the present invention Display devices for color self-luminous elements, especially OLEDs, not only have high contrast, but also high reliability, long-term high contrast, and high color reproducibility.

Claims (26)

A polarizing element characterized in that it comprises a substrate containing an azo compound and having a polarizing function, and a substrate has a transmittance of 45% to 60%, and an average transmittance of 440 nm to 500 nm is 50. % or more, the average transmittance of 550 nm to 650 nm obtained by measuring two sheets of the substrate perpendicular to the absorption axis direction is 10% or less. The polarizing element of claim 1, wherein the substrate having the azo compound and having a polarizing function has an average transmittance of 440 nm to 500 nm obtained by measuring two substrates perpendicular to the absorption axis direction. 15% or more, the average transmittance of 550 nm to 650 nm of one of the substrates is 40% or more. The polarizing element according to claim 1 or 2, wherein the substrate having the azo compound and having a polarizing function has an average transmission of 500 nm to 550 nm obtained by measuring two substrates perpendicular to the absorption axis direction. The rate is 20% or less, and the average transmittance of 500 nm to 550 nm of one substrate is 45% or more. The polarizing element according to any one of claims 1 to 3, which has a degree of polarization of 60% or more. The polarizing element according to any one of claims 1 to 4, wherein at least one of the azo compounds contained in the substrate contains the azo compound represented by the formula (1) in the form of a free acid, (A ₁ represents a phenyl group or a naphthyl group having a substituent, R ₁ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, and X ₁ represents a benzene which may have a substituent Amino group). The polarizing element according to any one of claims 1 to 4, wherein at least one of the azo compounds contained in the substrate contains the azo compound represented by the formula (2) in the form of a free acid, (A ₂ represents a phenyl group having a substituent, and R ₂ to R ₅ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, and X ₂ represents a substitutable group. A phenylamino group, but R ₂ to R ₅ do not satisfy the case where all of them are lower alkoxy groups). The polarizing element according to any one of claims 1 to 4, wherein at least one of the azo compounds contained in the substrate contains the azo compound represented by the formula (3) in the form of a free acid, (A ₃ represents a nitro group or an amine group, and R ₆ and R ₇ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group or a lower alkoxy group having a sulfo group, and X ₃ represents a substituent group; Phenylamino group). The polarizing element according to any one of claims 1 to 7, wherein two of the substrates are made to be sucked The average transmittance of 500 nm to 550 nm obtained by measurement in which the axial direction is orthogonal is 15% or less, the average transmittance of 440 nm to 500 nm of one substrate is 60% or more, and the average transmittance of 500 nm to 550 nm. More than 45%. The polarizing element according to any one of claims 1 to 8, wherein at least one of the azo compounds contained in the substrate contains at least one of the azo compounds represented by the formulas (1) to (3), and together The azo compound represented by the formula (4) is contained in the form of a free acid, (A ₄ represents a phenyl group or a naphthyl group having a substituent, and R ₈ or R ₉ each independently represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, or a lower alkoxy group having a sulfo group, X ₄ An amine group which may have a substituent, a benzhydrylamino group which may have a substituent, a phenylamine group which may have a substituent, a phenylazo group which may have a substituent, and a naphthalene which may have a substituent Azolyl). The polarizing element of claim 9, wherein X ₄ of the formula (4) is a phenylamine group which may have a substituent. The polarizing element of claim 9 or 10, wherein A ₄ of the formula (4) is a phenyl group having a substituent. The polarizing element according to any one of claims 1 to 8, wherein at least one of the azo compounds contained in the substrate contains at least one of the azo compounds represented by the formulas (1) to (3), and together The azo compound represented by the formula (5) is contained in the form of a free acid, (wherein R ₁₀ and R ₁₁ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, a lower alkoxy group having a sulfo group, a carbonyl group or a phenyl group or a naphthyl group having a halogen atom). The polarizing element of claim 12, wherein R ₁₀ and R _{11 of the} formula (5) are each independently a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, a lower alkoxy group having a sulfo group, a carbonyl group or a halogen group. Phenyl group of atoms. The polarizing element according to claim 13, wherein R ₁₀ and R ₁₁ each independently independently have at least one substituent which is a methoxy group, and further the other substituent is a sulfo group or a carbonyl group. The polarizing element according to any one of claims 5 to 8, wherein R ₁ of the formula (1) is a methyl group or a methoxy group. The polarizing element according to any one of claims 5 to 8, wherein A ₁ of the formula (1) is a phenyl group having a substituent. The polarizing element according to any one of claims 6 to 8, wherein at least one of R ₄ or R ₅ of the formula (2) is a methoxy group. The polarizing element according to any one of claims 6, 8 to 14 or 17, wherein at least one of R ₂ or R ₃ of the formula (2) is a methoxy group. The polarizing element according to any one of claims 6, 8 to 15, 17 or 18, wherein A ₂ of the formula (2) is a phenyl group having a substituent. The polarizing element according to any one of claims 7 to 15, wherein at least one of R ₆ and R ₇ of the formula (3) is a methoxy group. The polarizing element according to any one of claims 7 to 15, wherein R ₆ and R ₇ of the formula (3) are a methoxy group. The polarizing element according to any one of claims 1 to 21, wherein the substrate comprises a polyvinyl alcohol-based resin film. The polarizing element according to any one of claims 1 to 22, which is provided with a phase difference plate having a phase difference of 120 nm to 150 nm. A polarizing plate obtained by providing a support film on at least one side of a polarizing element according to any one of claims 1 to 23. The polarizing plate of claim 24, which is provided with a phase difference plate having a phase difference of 120 nm to 150 nm. An organic electroluminescence display device using the polarizing element according to any one of claims 1 to 23 or the polarizing plate of claim 24 or 25.