JP5923941B2 - Polarizing film, circularly polarizing plate, and organic EL image display device using them - Google Patents

Description

  The present invention relates to a polarizing film, a circularly polarizing plate, and an organic EL image display device using them.

  In an organic EL image display device, a circularly polarizing plate is used to prevent reflection of external light in a bright place. As such a circularly-polarizing plate, what contains the polarizing film (iodine-PVA polarizing film) which dye | stained PVA (polyvinyl alcohol) with the iodine is known, for example (for example, refer patent document 1).

JP-A-7-142170

  However, in the organic EL image display device provided with the conventional circularly polarizing plate including the polarizing film, there is a problem that the polarizing film absorbs light from the organic EL light emitting element about half of the light amount. For this reason, it is necessary to increase the light emission intensity of the organic EL light emitting element, which causes a shortened life of the organic EL image display device. In particular, blue light with a short lifetime (light-emitting element having a wavelength of around 450 nm) was markedly deteriorated over time. However, a circularly polarizing plate and a polarizing film that can solve the above problems have never been realized.

［式（１）中、
ｎは１又は２である。
Ａｒ_１及びＡｒ_３は、それぞれ独立に下記に示す基から選ばれる。

Ａｒ_２は下記に示す基から選ばれる。

Ａ_１及びＡ_２は、それぞれ独立に下記に示す基から選ばれる。

ｍは０〜１０の整数であり、同一の基中にｍが２つある場合、この２つのｍは互いに同一又は相異なる。］
〔４〕視感度補正単体透過率Ｔｙが４３％以上であり、視感度補正単体偏光度Ｐｙが９０％以上である前記〔１〕〜〔３〕のいずれか記載の偏光膜。
〔５〕前記〔１〕〜〔４〕のいずれか記載の偏光膜とλ/４層とを有し、
以下の（Ａ１）及び（Ａ２）の要件を満たす円偏光板（以下、場合により「本円偏光板」という）。
（Ａ１）前記偏光膜の吸収軸と、前記λ/４層の遅相軸とのなす角度が、略４５°であること；
（Ａ２）波長５５０ｎｍの光で測定した、前記λ/４層の正面リタデーションの値が１００〜１５０ｎｍの範囲であること
〔６〕前記λ/４層の可視光に対する正面リタデーションの値が、波長が短くなるに従って小さくなる特性を有する前記〔５〕記載の円偏光板。
〔７〕前記〔１〕〜〔４〕のいずれか記載の偏光膜とλ/２層とλ/４層とをこの順に有し、
以下の（Ｂ１）〜（Ｂ４）の要件を満たす円偏光板。
（Ｂ１）前記偏光膜の吸収軸と、前記λ/２層の遅相軸とのなす角度が、略１５°であること；
（Ｂ２）前記λ/２層の遅相軸と、前記λ/４層の遅相軸とのなす角度が、略６０°であること；
（Ｂ３）前記λ/２層が、波長５５０ｎｍの光で測定した、前記λ/４層の正面リタデーションの値が２００〜３００ｎｍの範囲であること；
（Ｂ４）前記λ/４層が、波長５５０ｎｍの光で測定した、前記λ/４層の正面リタデーションの値が１００〜１５０ｎｍの範囲であること
〔８〕前記〔５〕〜〔７〕のいずれか記載の円偏光板と、有機ＥＬ素子とを備えた有機ＥＬ表示装置（以下、場合により「本有機ＥＬ表示装置」という）。
〔９〕発光層から発光される光のうち、波長４５０ｎｍの光の強度をＩ４５０、波長５５０ｎｍの光の強度をＩ５５０、波長６５０ｎｍの光の強度をＩ６５０としたとき、
１≦Ｉ４５０／Ｉ５５０＜２ （Ｘ）
１≦Ａ４５０／Ａ６５０＜２ （XI）
で示される関係をすべて満たす発光スペクトルを有する前記〔８〕記載の有機ＥＬ表示装置。 The present invention includes the following inventions.
[1] It is formed from a composition containing two or more dichroic dyes having different maximum absorption wavelengths,
Having one orientation direction;
The following formulas (I) to (V)
0.3 ≦ A450 / A550 <0.8 (I)
0.3 ≦ A450 / A650 <1.0 (II)
0.5 ≦ A450 ≦ 2 (III)
1 ≦ A550 ≦ 3 (IV)
1 ≦ A650 ≦ 3 (V)
(Where
A450 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 450 nm,
A550 is the absorbance of polarized light parallel to the alignment direction at a wavelength of 550 nm,
A650 represents the absorbance of polarized light parallel to the alignment direction at a wavelength of 650 nm. )
A polarizing film having an absorption spectrum that satisfies all of the relationships indicated by (hereinafter referred to as “the present polarizing film”).
[2] The polarizing film according to [1], wherein the composition further contains a polymerizable smectic liquid crystal compound.
[3] The polarizing film according to [1] or [2], wherein both of the two or more dichroic dyes are polyazo dye materials represented by the following formula (1).

[In Formula (1),
n is 1 or 2.
Ar ₁ and Ar ₃ are each independently selected from the groups shown below.

Ar ₂ is selected from the following groups.

A ₁ and A ₂ are each independently selected from the groups shown below.

m is an integer of 0 to 10, and when there are two m's in the same group, these two m's are the same or different from each other. ]
[4] The polarizing film according to any one of [1] to [3], wherein the visibility corrected single transmittance Ty is 43% or more and the visibility corrected single polarization degree Py is 90% or more.
[5] The polarizing film according to any one of [1] to [4] and a λ / 4 layer,
A circularly polarizing plate that satisfies the following requirements (A1) and (A2) (hereinafter sometimes referred to as “this circularly polarizing plate”).
(A1) The angle formed by the absorption axis of the polarizing film and the slow axis of the λ / 4 layer is approximately 45 °;
(A2) The value of the front retardation of the λ / 4 layer measured with light having a wavelength of 550 nm is in the range of 100 to 150 nm. [6] The value of the front retardation of the λ / 4 layer with respect to visible light is The circularly polarizing plate according to [5], wherein the circularly polarizing plate has a characteristic of becoming smaller as it becomes shorter.
[7] The polarizing film according to any one of [1] to [4], a λ / 2 layer, and a λ / 4 layer in this order,
A circularly polarizing plate that satisfies the following requirements (B1) to (B4).
(B1) The angle formed by the absorption axis of the polarizing film and the slow axis of the λ / 2 layer is approximately 15 °;
(B2) The angle formed between the slow axis of the λ / 2 layer and the slow axis of the λ / 4 layer is approximately 60 °;
(B3) The value of the front retardation of the λ / 4 layer measured with light having a wavelength of 550 nm is in the range of 200 to 300 nm.
(B4) The λ / 4 layer is measured with light having a wavelength of 550 nm, and the value of the front retardation of the λ / 4 layer is in the range of 100 to 150 nm. [8] Any of [5] to [7] An organic EL display device comprising the circularly polarizing plate described above and an organic EL element (hereinafter sometimes referred to as “the present organic EL display device”).
[9] Of the light emitted from the light emitting layer, when the intensity of light with a wavelength of 450 nm is I450, the intensity of light with a wavelength of 550 nm is I550, and the intensity of light with a wavelength of 650 nm is I650,
1 ≦ I450 / I550 <2 (X)
1 ≦ A450 / A650 <2 (XI)
The organic EL display device according to [8], wherein the organic EL display device has an emission spectrum satisfying all of the relationships represented by the above.

  According to the present polarizing film, when used in an organic EL image display device, a circularly polarizing plate (this circularly polarizing plate) in which absorption of light from an organic EL light emitting element, particularly absorption of light in the vicinity of a wavelength of 450 nm is reduced is provided. be able to.

It is sectional drawing which represents typically one Embodiment of the continuous manufacturing method of this polarizing film. FIG. 6 is a projection view schematically showing an angle formed by an absorption axis of the polarizing film and a slow axis of a λ / 4 layer in an embodiment of the circularly polarizing plate. It is sectional drawing which represents typically one Embodiment of the continuous manufacturing method of this polarizing film. It is sectional drawing which represents typically the structure of this organic EL display apparatus. FIG. 3 is a cross-sectional view schematically showing the layer order of part C of the organic EL display device 30. It is sectional drawing which represents typically the structure of this organic EL display apparatus.

As described above, the polarizing film is formed from a composition containing two or more dichroic dyes having different maximum absorption wavelengths.
Having one orientation direction;
The following formulas (I) to (V)
0.3 ≦ A450 / A550 <0.8 (I)
0.3 ≦ A450 / A650 <1.0 (II)
0.5 ≦ A450 ≦ 2 (III)
1 ≦ A550 ≦ 3 (IV)
1 ≦ A650 ≦ 3 (V)
(Where
A450 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 450 nm,
A550 is the absorbance of polarized light parallel to the alignment direction at a wavelength of 550 nm,
A650 represents the absorbance of polarized light parallel to the alignment direction at a wavelength of 650 nm. )
It has the absorption spectrum which satisfy | fills all these relationships.
By using the present polarizing film as a present circularly polarizing plate including a later-described polarizing film, a long-life organic EL display device can be realized.

A450 / A550 in the formula (I) more preferably satisfies the relationship of 0.5 ≦ A450 / A550 <0.8.
A450 / A650 in the formula (II) more preferably satisfies the relationship of 0.5 ≦ A450 / A650 <0.8.

  A450 in the formula (III) more preferably satisfies the relationship of 0.5 ≦ A450 ≦ 1.6, and A550 in the formula (IV) further satisfies the relationship of 1.0 ≦ A550 ≦ 2.0. Preferably, A650 in the formula (V) more preferably satisfies the relationship of 1.0 ≦ A650 ≦ 2.0.

The present inventors have widely used the iodine-PVA polarizing plate, so that two iodine complexes having maximum absorption at wavelengths of about 470 nm and a wavelength of about 600 nm are generated. Therefore, it is considered difficult to selectively reduce the absorption of light having a wavelength of 470 nm, and as a result of examining the dye contained in the polarizing film, it contains at least two dichroic dyes having different maximum absorption wavelengths. The present inventors have found that a polarizing film formed from a composition (hereinafter, sometimes referred to as “a polarizing film forming composition”) selectively reduces absorption of light having a wavelength of 470 nm, and has reached the present invention.
Hereinafter, a composition containing a dichroic dye material and a polymerizable smectic liquid crystal compound, which is a preferred embodiment of the present invention (hereinafter referred to as a “polarizing film forming composition” in some cases), referring to the drawings as necessary. ”) And the manufacturing method thereof, and the present circular polarizing plate and the manufacturing method thereof will be described. Note that the dimensions of the drawings attached to the present specification are arbitrary for easy viewing.

<Dichroic dye>
As described above, the polarizing film forming composition contains two or more dichroic dyes. The dichroic dye as used herein refers to a dye having a property that the absorbance in the major axis direction of the molecule is different from the absorbance in the minor axis direction. The dichroic dye is not particularly limited as long as it has such properties, and may be a dye or a pigment. A plurality of these dyes may be used, a plurality of pigments may be used, or a dye and a pigment may be combined.

  The dichroic dye preferably has a maximum absorption wavelength (λMAX) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes. Among these, the dichroic dye is preferably an azo dye. Examples of the azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, with bisazo dyes and trisazo dyes being preferred.

［式（１）中、
ｎは１又は２である。
Ａｒ_１及びＡｒ_３は、それぞれ独立に下記に示す基から選ばれる。

Ａｒ_２は下記に示す基から選ばれる。

Ａ_１及びＡ_２は、それぞれ独立に下記に示す基から選ばれる。

（ｍは０〜１０の整数であり、同一の基中にｍが２つある場合、この２つのｍは互いに同一又は相異なる。）］ The azo dye is particularly preferably an azo dye represented by the above formula (1) (hereinafter sometimes referred to as “azo dye (1)”). More preferably, the azo dye (1) exhibits absorption within a wavelength range of 400 to 800 nm. Again, formula (1) is shown below.

[In Formula (1),
n is 1 or 2.
Ar ₁ and Ar ₃ are each independently selected from the groups shown below.

Ar ₂ is selected from the following groups.

A ₁ and A ₂ are each independently selected from the groups shown below.

(M is an integer of 0 to 10, and when there are two m's in the same group, these two m's are the same or different from each other.)]

  The positional isomerism of the azobenzene moiety of the azo dye (1) is preferably trans.

Examples of the azo dye (1) include compounds represented by formulas (1-1) to (1-28).

  Among the specific examples of the azo dye (1), the composition for forming a polarizing film for producing the present polarizing film includes the formula (1-2), formula (1-5), formula (1-6), formula (1-8), Formula (1-10), Formula (1-12), Formula (1-13), Formula (1-15), Formula (1-16), Formula (1-19), Formula ( 1-20), Formula (1-21), Formula (1-22), Formula (1-23), Formula (1-24), and Formula (1-26) are more preferable than those represented respectively. 1-2), Formula (1-5), Formula (1-8), Formula (1-10), Formula (1-15), Formula (1-21), Formula (1-22), and Formula (1) Those represented by -26) are particularly preferred.

［式（１−２８）中、
Ｒ^１〜Ｒ^８は、互いに独立に、水素原子、−Ｒ^ｘ、−ＮＨ_２、−ＮＨＲ^ｘ、−ＮＲ^ｘ _２、−ＳＲ^ｘ又はハロゲン原子を表す。
Ｒ^ｘは、炭素数１〜４のアルキル基又は炭素数６〜１２のアリール基を表す。］ As the anthraquinone dye, a compound represented by the formula (1-28) is preferable.

[In the formula (1-28),
R ^{1 to} R ⁸ each independently represent a hydrogen atom, —R ^x , —NH ₂ , —NHR ^x , —NR ^x ₂ , —SR ^x, or a halogen atom.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

［式（１−２９）中、
Ｒ^９〜Ｒ^１５は、互いに独立に、水素原子、−Ｒ^ｘ、−ＮＨ_２、−ＮＨＲ^ｘ、−ＮＲ^ｘ _２、−ＳＲ^ｘ又はハロゲン原子を表す。
Ｒ^ｘは、炭素数１〜４のアルキル基又は炭素数６〜１２のアリール基を表す。］ As the acridine dye, a compound represented by the formula (1-29) is preferable.

[In the formula (1-29),
R ^{9 to} R ¹⁵ each independently represent a hydrogen atom, —R ^x , —NH ₂ , —NHR ^x , —NR ^x ₂ , —SR ^x, or a halogen atom.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

［式（１−３０）中、
Ｒ^１６〜Ｒ^２３は、互いに独立に、水素原子、−Ｒ^ｘ、−ＮＨ_２、−ＮＨＲ^ｘ、−ＮＲ^ｘ _２、−ＳＲ^ｘ又はハロゲン原子を表す。
Ｒ^ｘは、炭素数１〜４のアルキル基又は炭素数６〜１２のアリール基を表す。］ As the oxazone dye, a compound represented by the formula (1-30) is preferable.

[In the formula (1-30),
R ¹⁶ to R ²³ independently represent a hydrogen _{^{atom, -R x, -NH 2, -NHR}} x, -NR x 2, -SR x , or halogen atom.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

In the above formula (1-28), formula (1-29) and formula (1-30), the alkyl group having 1 to 6 carbon atoms of R ^x is a methyl group, an ethyl group, a propyl group, a butyl group, Examples thereof include a pentyl group and a hexyl group, and examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a toluyl group, a xylyl group, and a naphthyl group.

［式（１−３１）中、
Ｄ^１及びＤ^２は、互いに独立に、式（１−３１ａ）〜式（１−３１ｄ）のいずれかで表される基を表す。

ｎ５は１〜３の整数を表す。］ As the cyanine dye, a compound represented by the formula (1-31) and a compound represented by the formula (1-32) are preferable.

[In the formula (1-31),
D ¹ and D ² each independently represent a group represented by any one of formulas (1-31a) to (1-31d).

n5 represents an integer of 1 to 3. ]

［式（１−３２）中、
Ｄ^３及びＤ^４は、互いに独立に、式（１−３２ａ）〜式（１−３２ｈ）のいずれかで表される基を表す。

ｎ６は１〜３の整数を表す。］

[In the formula (1-32),
D ³ and D ⁴ each independently represent a group represented by any one of formulas (1-32a) to (1-32h).

n6 represents an integer of 1 to 3. ]

  As mentioned above, although the preferable example was demonstrated about the dichroic dye which the said composition for polarizing film formation contains, the dichroic dye which this composition for polarizing film formation contains is an azo dye (1). It is more preferable that at least two kinds of azo dyes (1) having different maximum absorption wavelengths are contained.

  The dichroic dye contained in the composition for forming a polarizing film is 2 or more, more preferably 2 to 3 dichroic dyes, and more preferably 2 to 3 azo dyes (1). It is more preferable to contain. A combination of these two to three azo dyes (1) [represented by the names “first dye”, “second dye” and “third dye”. ], When a suitable combination is represented by a combination of the azo dyes (1) represented by the above formulas (1-1) to (1-27), dichroic dyes shown in Tables 1 and 2 The combination of (1) is mentioned.

この表１に示したアゾ色素（１）の組み合わせを含有する偏光膜形成用組成物によれば、後述する本偏光膜の製造方法により、前記式（Ｉ）〜式（Ｖ）で示される関係をすべて満たす吸収スペクトルを有する本偏光膜が得られやすくなる。
なお、表１における表記は、上述のアゾ色素（１）の具体例の符号に対応しており、例えば、「１−５」とは、式（１−５）で表されるアゾ色素（１）を意味する。

According to the composition for forming a polarizing film containing the combination of the azo dyes (1) shown in Table 1, the relationships represented by the above formulas (I) to (V) are obtained by the method for manufacturing the polarizing film described later. This polarizing film having an absorption spectrum satisfying all of the above can be easily obtained.
The notation in Table 1 corresponds to the reference numerals of the specific examples of the azo dye (1) described above. For example, “1-5” is an azo dye represented by the formula (1-5) (1 ).

  The content of the dichroic dye in the polarizing film forming composition can be appropriately adjusted according to the type of the dichroic dye, etc., for example, for a total of 100 parts by mass of the polymerizable liquid crystal compound described later, 0.1 parts by mass or more and 50 parts by mass or less are preferable, 0.1 parts by mass or more and 20 parts by mass or less are more preferable, and 0.1 parts by mass or more and 10 parts by mass or less are more preferable. When the content of the dichroic dye is within this range, the polymerizable liquid crystal compound can be polymerized without disturbing the alignment of the polymerizable liquid crystal compound. When there is too much content of a dichroic dye, there exists a possibility of inhibiting the orientation of a polymerizable liquid crystal compound. Therefore, the content of the dichroic dye can be determined within a range in which the polymerizable liquid crystal compound can maintain the liquid crystal state. In addition, content of dichroic dye here is calculated | required from the sum total of 2 or more types of dichroic dyes.

<Polymerizable liquid crystal compound>
The composition for forming a polarizing film preferably contains a polymerizable liquid crystal compound in that a polarizing film having practical strength can be obtained. The polymerizable liquid crystal compound is a compound having a polymerizable group and exhibiting a liquid crystal state. The polymerizable group means a group involved in the polymerization reaction of the polymerizable liquid crystal compound. Among the polymerizable liquid crystal compounds, a polymerizable smectic liquid crystal compound is more preferable than a polymerizable nematic liquid crystal compound from the viewpoint of polarization performance.

  The liquid crystal state exhibited by the polymerizable smectic liquid crystal compound is more preferably a higher order smectic phase. The high-order smectic phase here means a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, and a smectic L phase. Among them, a smectic B phase, a smectic F phase, and a smectic I phase are more preferable. The polarizing film having a high degree of orientational order can be obtained depending on the liquid crystal state exhibited by the polymerizable smectic liquid crystal compound. In addition, the polarizing film having such a high degree of orientational order can obtain a Bragg peak in the X-ray reflection measurement.

As a preferable polymerizable smectic liquid crystal compound, for example, a compound represented by the formula (2) (hereinafter sometimes referred to as “compound (2)”) may be mentioned.
^{U 1 -V 1 -W 1 -X 1} -Y 1 -X 2 -Y 2 -X 3 -W 2 -V 2 -U 2 (2)
[In Formula (2),
X ¹ , X ² and X ³ each independently represent a p-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. However, at least one of X ¹ , X ² and X ³ is a p-phenylene group which may have a substituent.
Y ¹ and ^{Y 2,} independently of one _{another, -CH 2 CH 2 -, -} CH 2 O -, - COO -, - OCOO-, a single ^{bond, -N = N -, - CR} a = CR b -, - C≡C— or —CR ^a ═N— is represented. R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
U ¹ represents a hydrogen atom or a polymerizable group.
U ² represents a polymerizable group.
W ¹ and W ² each independently represent a single bond, —O—, —S—, —COO— or —OCOO—.
V ¹ and V ² each independently represent an optionally substituted alkanediyl group having 1 to 20 carbon atoms, and —CH ₂ — constituting the alkanediyl group is —O—, — S- or -NH- may be substituted. ]

In the compound (2), as described above, at least one of X ¹ , X ² and X ³ is a 1,4-phenylene group which may have a substituent. Are preferably a p-phenylene group which may have a substituent.
The p-phenylene group is preferably unsubstituted. The cyclohexane-1,4-diyl group is preferably a trans-cyclohexane-1,4-diyl group, and the trans-cyclohexane-1,4-diyl group is also unsubstituted. Is more preferable.

Examples of the substituent that the p-phenylene group or the cyclohexane-1,4-diyl group optionally has include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, and a butyl group; a cyano group; a halogen atom Etc. In addition, —CH ₂ — constituting the cyclohexane-1,4-diyl group may be replaced by —O—, —S— or —NR—. R is a C1-C6 alkyl group or a phenyl group.

Y ¹ of the compound (2) is preferably —CH ₂ CH ₂ —, —COO— or a single bond, and Y ² is preferably —CH ₂ CH ₂ — or —CH ₂ O—.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, and preferably a polymerizable group. That is, both U ¹ and U ² are preferably a polymerizable group, and both are preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described later. The use of a polymerizable smectic liquid crystal compound having a photopolymerizable group is also advantageous in that the polymerizable smectic liquid crystal compound can be polymerized under a lower temperature condition.

In the compound (2), the photopolymerizable groups of U ¹ and U ² may be different from each other, but are preferably the same type. Examples of the photopolymerizable group include a vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. U ¹ and U ² are the same type of photopolymerizable group, for example, when U ¹ and U ² are both acryloyloxy groups.

Examples of the alkanediyl group of V ¹ and V ² include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, and a pentane-1,5. -Diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, decane-1,10-diyl group, tetradecane-1,14-diyl group and icosane And a -1,20-diyl group. V ¹ and V ² are preferably alkanediyl groups having 2 to 12 carbon atoms, and more preferably alkanediyl groups having 6 to 12 carbon atoms.
Examples of the substituent that the alkanediyl group optionally has include a cyano group and a halogen atom. The alkanediyl group is preferably unsubstituted, and is an unsubstituted and linear alkanediyl group. It is more preferable that

W ¹ and W ² are independently of each other, preferably a single bond or —O—.

  Examples of compound (2) include compounds represented by formulas (2-1) to (2-23). When a specific example of the compound (2) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans isomer.

The exemplified compound (2) can be used alone or in admixture of two or more for the composition for forming a polarizing film. Further, two or more kinds of polymerizable smectic liquid crystal compounds may be used, and at least one of the two or more kinds of polymerizable smectic liquid crystal compounds may be compound (2). In the following description, the case where a single type of polymerizable smectic liquid crystal compound is used and the case where two or more types of polymerizable smectic liquid crystal compounds are used may be collectively referred to as “polymerizable smectic liquid crystal compound”.
When the compound (2) is used in the composition for forming a polarizing film, the phase transition temperature of the compound (2) is obtained in advance, and the polarization is performed so that the compound (2) is polymerized under a temperature condition lower than the phase transition temperature. Components other than the compound (2) [polymerizable smectic liquid crystal compound] of the film-forming composition are adjusted. Examples of the component capable of controlling the polymerization temperature include a photopolymerization initiator, a photosensitizer, and a polymerization inhibitor described later. The polymerization temperature of the compound (2) can be controlled by adjusting these types and amounts as appropriate. In addition, also when using the mixture of 2 or more types of compounds (2) [polymerizable smectic liquid crystal composition] for the composition for polarizing film formation, the phase transition temperature of the mixture of the 2 or more types of compounds (2) is used. After the determination, the polymerization temperature is controlled in the same manner as in the case of the polymerizable smectic liquid crystal compound.

  Among the exemplified compounds (2), formula (2-2), formula (2-3), formula (2-4), formula (2-6), formula (2-7), formula (2-8) And at least one selected from the group consisting of those represented by formula (2-13), formula (2-14) and formula (2-15). These compounds (2) are easily mixed under a temperature condition lower than the phase transition temperature by mixing two or more kinds or by interaction with the photopolymerization initiator used together, that is, a higher-order smectic phase. The compound (2) can be polymerized while sufficiently maintaining the liquid crystal state. More specifically, due to the interaction with the photopolymerization initiator, these compounds (2) sufficiently exhibit a liquid crystal state of a high-order smectic phase under a temperature condition of 70 ° C. or less, preferably 60 ° C. or less. Polymerization can be carried out while being held.

  As described above, the compound (2) contained in the composition for forming a polarizing layer may be a single type or a plurality of types (two or more types), but is preferably a plurality of types.

  When the polarizing film-forming composition containing the compound (2) is used, the content ratio of the compound (2) is preferably 70 to 99.9% by mass with respect to the solid content of the polarizing film-forming composition. 90-99.9 mass% is more preferable. If the content rate of a compound (2) is in the said range, there exists a tendency for the orientation of a compound (2) to become high. Here, solid content means the total amount of the component remove | excluding volatile components, such as a solvent, from this polarizing film formation composition. In addition, when multiple types of compound (2) is contained in this polarizing film formation composition, the total content rate should just be the said range. As already described, the polarizing film-forming composition used in the present invention may contain a polymerizable liquid crystal compound other than the compound (2), but the polymerizable property contained in the polarizing film-forming composition. It is preferable that the liquid crystal compound is substantially only the compound (2).

<Solvent>
The composition for forming a polarizing film may contain a solvent. In general, since the polymerizable smectic liquid crystal compound has a high viscosity, application to the polarizing film forming composition dissolved in a solvent becomes easy, and as a result, the polarizing film is often easily formed. As the solvent, a solvent capable of dissolving the polymerizable smectic liquid crystal compound and the dichroic dye is preferable. Moreover, it is preferable that it is an inert solvent with respect to the polymerization reaction of the composition for polarizing film formation.
Solvents include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone Or ester solvents such as propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; toluene And xylene (the xylene may be any of o-, m- and p-bodies, Al may be a mixture of two or more kinds selected) aromatic hydrocarbon solvents, nitrile solvents such as acetonitrile and the like;. Chlorine-containing solvents such as chloroform and chlorobenzene; ethers solvents such as tetrahydrofuran and dimethoxyethane, and the like. These solvents may be used alone or in combination of two or more.

  As for content of a solvent, 50-98 mass% is preferable with respect to the total amount of the said composition for polarizing film formation. In other words, the solid content in the composition for forming a polarizing film is preferably 2 to 50% by mass. When the solid content is 2% by mass or more, a thin main polarizing film tends to be obtained. On the other hand, when the solid content is 50% by mass or less, since the viscosity of the composition for forming a polarizing film is lowered, the thickness of the polarizing film tends to be substantially uniform, so that unevenness of the polarizing film is less likely to occur. There is. Moreover, this solid content can be determined so that the desired thickness of the polarizing film mentioned later can be formed.

<Polymerization reaction aid>
The composition for forming a polarizing layer preferably contains a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction of a polymerizable smectic liquid crystal compound, and a photopolymerization initiator is preferable in that the polymerization reaction can be initiated under a lower temperature condition. Specifically, a compound capable of generating an active radical or an acid by the action of light is used as a photopolymerization initiator. Among the photopolymerization initiators, those that generate radicals by the action of light are more preferable.

  Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts, and sulfonium salts.

Hereinafter, specific examples of this photopolymerization initiator will be given.
Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

  Examples of the benzophenone compound include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, 3,3 ′, 4,4′-tetra (tert-butylperoxycarbonyl). ) Benzophenone and 2,4,6-trimethylbenzophenone.

  Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1- (4-methylthiophenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl). ) Butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1 -[4- (2-hydroxyethoxy) phenyl] propan-1-one, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propane-1- ON oligomers.

  Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide.

  Examples of the triazine compound include 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- (4-methoxy Naphthyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- (4-methoxystyryl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6 [2- (5-Methylfuran-2-yl) ethenyl] -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (furan-2-yl) ethenyl] -1 , 3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (4-diethylamino-2-methylphenyl) ethenyl] -1,3,5-triazine and 2,4-bis (trichloro Methyl)- - such as [2- (3,4-dimethoxyphenyl) ethenyl] -1,3,5-triazine.

  A photopolymerization initiator that can be easily obtained from the market can also be used. Commercially available photopolymerization initiators include “Irgacure 907”, “Irgacure 184”, “Irgacure 651”, “Irgacure 819”, “Irgacure 250”, “Irgacure 369” (Ciba Japan Co., Ltd.); “Sake All BZ”, “Sake All Z”, “Sake All BEE” (Seiko Chemical Co., Ltd.); “Kayacure BP100” (Nippon Kayaku Co., Ltd.); “Kayacure UVI-6992” (manufactured by Dow); “Adekaoptomer SP-152”, “Adekaoptomer SP-170” (ADEKA); “TAZ-A”, “TAZ-PP” (Nihon Shibel Hegner); and “TAZ-104” (Sanwa) Chemical Corporation).

  When the polarizing film-forming composition contains a polymerization initiator, the content depends on the type and amount of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) contained in the polarizing film-forming composition. The content of the polymerization initiator is preferably from 0.1 to 30 parts by weight, for example from 0.5 to 20 parts by weight, based on a total of 100 parts by weight of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound). Is more preferable, and 0.5 to 10 parts by mass is even more preferable. If the content of the polymerizable initiator is within this range, the polymerizable smectic liquid crystal compound can be polymerized without disturbing the orientation of the polymerizable smectic liquid crystal compound, so that the polymerizable smectic liquid crystal compound exhibits a liquid crystal state of a higher order smectic phase. Polymerization can be carried out while being held.

  When the polarizing film-forming composition contains a photopolymerization initiator, the polarizing film-forming composition may contain a photosensitizer. Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone (for example, 2,4-diethylthioxanthone and 2-isopropylthioxanthone); anthracene and alkoxy group-containing anthracene (for example, dibutoxyanthracene) and the like. Anthracene compounds; phenothiazine, rubrene, and the like.

  When the composition for forming a polarizing film contains a photopolymerization initiator and a photosensitizer, a polymerization reaction of a polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) contained in the composition for forming a polarizing film Can be promoted more. The amount of the photosensitizer used can be appropriately adjusted according to the type and amount of the photopolymerization initiator and polymerizable smectic liquid crystal compound used together. For example, the total amount of the polymerizable smectic liquid crystal compound is 100 parts by mass. 0.1-30 mass parts is preferable, 0.5-10 mass parts is more preferable, 0.5-8 mass parts is further more preferable.

  It has been explained that the polymerization reaction of a polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) can be promoted by including a photosensitizer in the composition for forming a polarizing film, but in order to promote the polymerization reaction stably. In addition, a polymerization inhibitor can be appropriately contained in the composition for forming a polarizing film. By containing the polymerization inhibitor, the degree of progress of the polymerization reaction of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) can be controlled.

  Examples of the polymerization inhibitor include radicals such as hydroquinone, alkoxy group-containing hydroquinone, alkoxy group-containing catechol (eg, butyl catechol), pyrogallol, 2,2,6,6-tetramethyl-1-piperidinyloxy radical, and the like. Supplementary agents; thiophenols; β-naphthylamines and β-naphthols.

  In the case where a polymerization inhibitor is contained in the polarizing film forming composition, the content can be appropriately adjusted according to the type and amount of the polymerizable smectic liquid crystal compound to be used, the amount of photosensitizer used, and the like. For example, the content of the polymerization inhibitor with respect to 100 parts by mass of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and 0.5 to 8 parts by mass is more preferable. If the content of the polymerization inhibitor is within this range, it can be polymerized without disturbing the orientation of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) contained in the polarizing film forming composition, The polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) can be further polymerized while maintaining the liquid crystal state of a higher order smectic phase.

<Leveling agent>
The composition for forming a polarizing film preferably contains a leveling agent. The leveling agent has a function of adjusting the fluidity of the composition for forming a polarizing film, and making the coating film obtained by applying the composition for forming a polarizing film more flat, such as a surfactant. Can be mentioned. The leveling agent is more preferably at least one selected from the group consisting of a leveling agent having a polyacrylate compound as a main component and a leveling agent having a fluorine atom-containing compound as a main component.

  Leveling agents mainly composed of polyacrylate compounds include “BYK-350”, “BYK-352”, “BYK-353”, “BYK-354”, “BYK-355”, “BYK-358N”, “ BYK-361N ”,“ BYK-380 ”,“ BYK-381 ”,“ BYK-392 ”[BYK Chemie], and the like.

  Leveling agents mainly composed of fluorine atom-containing compounds include "Megafac R-08", "R-30", "R-90", "F-410", "F-411", "F-443", "F-445", "F-470", "F-471", "F-477", "F-479", "F-482" and the same "F-483" [DIC Corporation]; "Surflon S-381", "S-382", "S-383", "S-393", "SC-101", "SC" -105 "," KH-40 "and" SA-100 "[AGC Seimi Chemical Co., Ltd.];" E1830 "," E5844 "[Daikin Fine Chemical Laboratory Co., Ltd.];" F-top EF301 "," EF303 " ", EF351" and "EF352" [Mitsubishi Materials Child Kasei Co., Ltd.] and the like.

  When the leveling agent is contained in the polarizing film forming composition, the content is preferably 0.3 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound). 0.5 parts by mass or more and 3 parts by mass or less are more preferable. When the content of the leveling agent is within the above range, it is easy to horizontally align the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound), and the obtained polarizing film tends to be smoother. When the content of the leveling agent with respect to the polymerizable smectic liquid crystal compound exceeds the above range, unevenness tends to occur in the obtained polarizing film. In addition, this polarizing film formation composition may contain 2 or more types of leveling agents.

<Formation method of this polarizing film>
Next, a method for forming the polarizing film from the polarizing film forming composition will be described. In such a method, it is preferable to form the polarizing film by applying the composition for forming a polarizing film on a substrate, preferably on a transparent substrate.

<Transparent substrate>
The said transparent base material is a base material which has the transparency which can permeate | transmit light, especially visible light. The transparency refers to a characteristic that the transmittance with respect to a light beam having a wavelength of 380 to 780 nm is 80% or more. Specific examples of such transparent substrates include glass substrates, plastic translucent sheets, and translucent films. Examples of the plastic constituting the translucent sheet or translucent film include polyolefins such as polyethylene, polypropylene and norbornene polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylates; Acid esters; cellulose esters such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate; polyethylene naphthalates; polycarbonates; polysulfones; polyether sulfones; polyether ketones; and plastics such as polyphenylene sulfide and polyphenylene oxide. Among the specific examples of the transparent substrate described above, a plastic light-transmitting film, that is, a polymer film is preferable in view of a preferable plastic light-transmitting sheet and light-transmitting film. Among the polymer films, a polymer film made of cellulose ester, cyclic olefin resin, polyethylene terephthalate or polymethacrylic acid ester is particularly preferable because it can be easily obtained from the market or has excellent transparency. Is preferred. In producing the polarizing film using such a transparent substrate, the transparent substrate can be easily handled without causing damage such as tearing when the transparent substrate is transported or stored. A support base material or the like may be pasted. Moreover, although mentioned later, when manufacturing a circularly-polarizing plate from this polarizing film, retardation may be provided to this transparent base material. In this case, a polymer film is prepared as a transparent substrate, and the polymer film is subjected to stretching treatment to impart retardation to the polymer film to obtain a retardation film. A conductive film may be used as a transparent substrate. The method for imparting retardation to the transparent substrate (polymer film) will be described later.

Among the polymer films, a film made of a cellulose ester, a polycarbonate or a cyclic olefin resin (a cellulose ester film, a polycarbonate film, a cyclic olefin is used in that the retardation value is easily controlled when the retardation is imparted. Based resin film) is preferred. Hereinafter, these three types of polymer films will be described in detail.
The cellulose ester constituting the cellulose ester film is one in which at least a part of hydroxyl groups contained in cellulose is converted to acetate ester. A cellulose ester film comprising such a cellulose ester can be easily obtained from the market. Examples of commercially available triacetyl cellulose films include “Fujitac Film” (Fuji Photo Film Co., Ltd.); “KC8UX2M”, “KC8UY” and “KC4UY” (Konica Minolta Opto Co., Ltd.). Such a commercially available triacetyl cellulose film can be used as a transparent substrate as it is or after imparting retardation as necessary. The surface of the prepared transparent substrate can be used as a transparent substrate after being subjected to surface treatment such as antiglare treatment, hard coat treatment, antistatic treatment or antireflection treatment.

  In order to impart retardation to the polymer film, as described above, the polymer film is stretched. Any polymer film made of plastic, that is, a thermoplastic resin can be stretched, but a cyclic olefin-based resin film is preferable in that the retardation can be easily controlled. The cyclic olefin resin constituting the cyclic olefin resin film is composed of, for example, a polymer or copolymer (cyclic olefin resin) of a cyclic olefin such as norbornene or a polycyclic norbornene monomer. The olefin resin may partially contain a ring opening. Moreover, what hydrogenated the cyclic olefin resin containing a ring opening part may be used. Further, the cyclic olefin resin is, for example, a copolymer of a cyclic olefin and a chain olefin or a vinylated aromatic compound (such as styrene) in that the transparency is not significantly impaired or the hygroscopicity is not significantly increased. It may be. The cyclic olefin resin may have a polar group introduced in its molecule.

  When the cyclic olefin resin is a copolymer of a cyclic olefin and an aromatic compound having a chain olefin or a vinyl group, the chain olefin is ethylene, propylene, or the like, and a vinylated aromatic Examples of the compound include styrene, α-methylstyrene, and alkyl-substituted styrene. In such a copolymer, the content ratio of the structural unit derived from the cyclic olefin is in the range of 50 mol% or less, for example, about 15 to 50 mol% with respect to all the structural units of the cyclic olefin resin. When the cyclic olefin-based resin is a terpolymer obtained from a cyclic olefin, a chain olefin, and a vinylated aromatic compound, for example, the content ratio of the structural unit derived from the chain olefin is the cyclic olefin. It is about 5-80 mol% with respect to all the structural units of a resin, and the content rate of the structural unit derived from a vinylated aromatic compound is about 5-80 mol%. Such a terpolymer cyclic olefin resin has the advantage that the amount of expensive cyclic olefin used can be relatively reduced when the cyclic olefin resin is produced.

  Cyclic olefin resins that can produce a cyclic olefin resin film are readily available from the market. Commercially available cyclic olefin-based resins include “Topas” [Ticona (Germany)]; “Arton” [JSR Corporation]; “ZEONOR” and “ZEONEX” [Nippon Zeon Corporation] “Apel” [Mitsui Chemicals, Inc.] and the like. Such a cyclic olefin-based resin can be formed into a film (cyclic olefin-based resin film) by, for example, known film forming means such as a solvent casting method or a melt extrusion method. Moreover, the cyclic olefin resin film already marketed with the form of a film can also be used. Examples of such commercially available cyclic olefin resin films include “Essina” and “SCA40” [Sekisui Chemical Co., Ltd.]; “Zeonor Film” [Optes Co., Ltd.]; “Arton Film” [JSR Co., Ltd.] ] Etc. are mentioned.

  Moreover, also in a polycarbonate film, the film provided with phase difference property can be obtained easily from a market. Examples of such a polycarbonate film include a uniaxially stretched film WRF-S [(modified polycarbonate resin) manufactured by Teijin Chemicals Ltd.].

  Next, a method for imparting retardation to the polymer film will be briefly described. The polymer film can be provided with retardation by a known stretching method. For example, a roll (winding body) in which a polymer film is wound on a roll is prepared, the film is continuously unwound from the winding body, and the unwound film is conveyed to a heating furnace. The set temperature of the heating furnace is in the range of near the glass transition temperature (° C.) to [glass transition temperature +100] (° C.) of the polymer film, preferably near the glass transition temperature (° C.) to [glass transition temperature +50] (° C. ). In the heating furnace, when the film is stretched in the direction of travel or in the direction perpendicular to the direction of travel, the transport direction and tension are adjusted, and the film is uniaxially or biaxially stretched at an arbitrary angle. . The draw ratio is usually in the range of about 1.1 to 6 times, preferably in the range of about 1.1 to 3.5 times. In addition, the method of stretching in an oblique direction is not particularly limited as long as the orientation axis can be continuously inclined to a desired angle, and a known stretching method can be employed. Examples of such a stretching method include the methods described in JP-A-50-83482 and JP-A-2-113920.

  When used as a transparent substrate, the thickness of the polymer film is preferably such that the weight is such that it can be handled practically and sufficient transparency can be ensured. Tends to be lowered and the processability tends to be inferior. Therefore, an appropriate thickness of these films is, for example, about 5 to 300 μm, preferably 20 to 200 μm. When this polarizing film is used as a circularly polarizing plate, which will be described later, since the display device using the circularly polarizing plate is assumed to be used for mobile purposes, the thickness of the film is particularly preferably about 20 to 100 μm. In addition, when giving retardation to a film by extending | stretching, the thickness after extending | stretching is determined by the thickness of the film before extending | stretching, and a draw ratio.

<Alignment film>
An alignment film is preferably formed on the base material used for the production of the polarizing film. In that case, the composition for forming a polarizing film is applied onto the alignment film. For this reason, it is preferable that the alignment film has a solvent resistance that does not dissolve when the polarizing film-forming composition is applied. Moreover, it is preferable to have heat resistance in the heat treatment for removing the solvent and aligning the liquid crystal. As the alignment film, an alignment polymer can be used.

  Examples of the orientation polymer include polyamides and gelatins having an amide bond in the molecule, polyimides having an imide bond in the molecule, and polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyacrylamide which are hydrolysates thereof. Mention may be made of polymers such as oxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid or polyacrylic acid esters. Among these, polyvinyl alcohol is preferable. These alignment polymers forming the alignment film may be used alone or in combination of two or more.

  The alignment polymer can be formed on the substrate by applying the alignment polymer on the substrate as an alignment polymer composition (solution containing the alignment polymer) dissolved in a solvent. The solvent used in the alignment polymer composition is not particularly limited, and specifically, water; alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone and methyl isobutyl ketone Solvents; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; aromatic hydrocarbon solvents such as toluene and xylene, acetonitrile, etc. Tolyl solvent; tetrahydrofuran and ether solvents such as dimethoxyethane; and the like are; chlorinated hydrocarbon solvent of chloroform and chlorobenzene. These organic solvents may be used alone or in combination of two or more.

  A commercially available alignment film material may be used as it is as the alignment polymer composition for forming the alignment film. Examples of commercially available alignment film materials include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optmer (registered trademark, manufactured by JSR).

  As a method for forming an alignment film on the substrate, for example, the alignment polymer composition or a commercially available alignment film material is applied on the substrate, and then annealed to align on the substrate. A film can be formed. The thickness of the alignment film thus obtained is, for example, in the range of 10 nm to 10000 nm, and preferably in the range of 10 nm to 1000 nm.

  In order to impart an alignment regulating force to the alignment film, it is preferable to perform rubbing (rubbing method) as necessary. By imparting the alignment regulating force, the polymerizable smectic liquid crystal compound can be aligned in a desired direction (alignment direction).

  As a method of applying an alignment regulating force by a rubbing method, for example, a rubbing cloth is wound, a rotating rubbing roll is prepared, and a laminate in which a coating film for forming an alignment film is formed on a substrate is staged. And a method of bringing the alignment film-forming coating film into contact with the rotating rubbing roll by transporting it toward the rotating rubbing roll.

  A so-called photo-alignment film can also be used. The photo-alignment film forms a photo-alignment inducing layer, and may impart an alignment regulating force by irradiating polarized light (preferably, polarized UV). In forming the photo-alignment inducing layer, first, a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter sometimes referred to as “photo-alignment layer forming composition”) is prepared. The photoreactive group refers to a group that generates liquid crystal alignment ability when irradiated with light (light irradiation). Specifically, it causes photoreactions that are the origin of liquid crystal alignment ability, such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photolysis reaction caused by light irradiation. is there. Among the photoreactive groups, those utilizing a dimerization reaction or a photocrosslinking reaction are preferable because they are excellent in orientation and maintain a smectic liquid crystal state when a polarizing layer is formed. As the photoreactive group capable of causing the above reaction, those having an unsaturated bond, particularly a double bond are preferable, and a carbon-carbon double bond (C═C bond), a carbon-nitrogen double bond (C = N bond), a group having at least one selected from the group consisting of a nitrogen-nitrogen double bond (N = N bond) and a carbon-oxygen double bond (C = O bond) is particularly preferable.

Examples of the photoreactive group having a C═C bond include a vinyl group, a polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C═N bond include groups having a structure such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N = N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group and a formazan group, and those having a basic structure of azoxybenzene. Examples of the photoreactive group having a C═O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a halogenated alkyl group.
Among them, a photoreactive group capable of causing a photodimerization reaction is preferable, and a cinnamoyl group and a chalcone group have a relatively small amount of polarized light irradiation necessary for photoalignment, and a photoalignment layer having excellent thermal stability and temporal stability. Since it is easy to obtain, it is preferable. Further, as the polymer having a photoreactive group, a polymer having a cinnamoyl group in which the terminal portion of the polymer side chain has a cinnamic acid structure is particularly preferable.

  By applying a polymer or monomer having a photoreactive group as a composition for forming a photo-alignment layer dissolved in a solvent on a transparent substrate, a photo-alignment inducing layer can be formed on the transparent substrate. The solvent used in the composition is not particularly limited, and solvents such as those used in the alignment polymer composition described above can be applied depending on the solubility of the polymer or monomer having a photoreactive group.

  The concentration of the polymer or monomer having a photoreactive group with respect to the composition for forming a photoalignment layer can be appropriately adjusted depending on the type of the polymer or monomer having the photoreactive group and the thickness of the photoalignment layer to be produced. Expressed in terms of solid content concentration, it is preferably at least 0.2 mass%, particularly preferably in the range of 0.3-10 mass%. In addition, the composition for forming an alignment layer may contain a polymer material such as polyvinyl alcohol or polyimide, or a photosensitizer as long as the characteristics of the photo-alignment layer are not significantly impaired.

  Examples of the method for applying the orientation polymer or the polymer or monomer having a photoreactive group on a transparent substrate include spin coating, extrusion, gravure coating, die coating, bar coating, and applicator method. A known method such as a coating method such as a flexographic method or the like is employed. In addition, when implementing this polarizing film manufacture by the continuous manufacturing method of the Roll to Roll format mentioned later, the printing methods, such as the gravure coating method, the die coating method, or a flexo method, are employ | adopted normally.

<Method for producing the polarizing film>
On the alignment film formed on the (transparent) substrate, the polarizing film forming composition is applied to obtain a coating film. Examples of the method for applying the composition for forming a polarizing film on the alignment film (application method) include, for example, a method for applying an alignment polymer or a polymer (monomer) having a photoreactive group on a transparent substrate. The same method is mentioned. In this method, the polarizing film forming composition will be described mainly with respect to a case where a polymerizable smectic liquid crystal compound is contained as the polymerizable liquid crystal compound.

  Next, a dry film is formed by drying and removing the solvent under the condition that the polymerizable smectic liquid crystal compound contained in the coating film is not polymerized. Examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method, and a vacuum drying method. At this time, it is preferable that once the liquid crystalline state of the polymerizable smectic liquid crystal composition contained in the dry film is changed to a nematic phase (nematic liquid crystal state), the nematic phase is transferred to the smectic phase. In order to form a smectic phase via the nematic phase in this way, for example, the polymerizable smectic liquid crystal compound contained in the dry film is heated to a temperature higher than the phase transition to the liquid crystal state of the nematic phase, and then the polymerizable A method is adopted in which the smectic liquid crystal compound is cooled to a temperature at which the smectic liquid crystal state is exhibited.

  When the polymerizable smectic liquid crystal compound in the dry film is in a smectic liquid crystal state, or when the polymerizable smectic liquid crystal compound is in a smectic liquid crystal state via a nematic liquid crystal state, the phase transition temperature of the polymerizable smectic liquid crystal compound to be used By measuring the above, the conditions (heating conditions) for controlling the liquid crystal state can be easily obtained. The measurement conditions for measuring the phase transition temperature will be described in the examples of the present application.

  When polymerizing the polymerizable smectic liquid crystal compound, a composition for forming a polarizing film comprising two or more polymerizable smectic liquid crystal compounds as the polymerizable smectic liquid crystal compound in order to maintain a liquid crystal state in a smectic phase satisfactorily. Is preferably used. When a polarizing film forming composition in which the content ratio of the two or more polymerizable smectic liquid crystal compounds is adjusted is used, a liquid crystal state of a smectic phase is formed via a nematic phase, and then a supercooled state is temporarily set. The liquid crystal state of a higher order smectic phase can be easily formed.

  Next, the polymerization process of the polymerizable smectic liquid crystal compound will be described. Here, a photopolymerization initiator is contained in the composition for forming a polarizing layer, and after the liquid crystal state of the polymerizable smectic liquid crystal compound in the dry film is changed to a smectic phase, the liquid crystal state of the smectic phase is maintained while the liquid crystal state is maintained. A method for photopolymerizing the polymerizable smectic liquid crystal compound will be described in detail. In the photopolymerization, the light applied to the dry film includes the type of photopolymerization initiator contained in the dry film, or the type of polymerizable smectic liquid crystal compound (in particular, the type of photopolymerizable group possessed by the polymerizable smectic liquid crystal compound). ) And an amount of the active electron beam selected from the group consisting of visible light, ultraviolet light, and laser light. Among these, ultraviolet light is preferable in that it is easy to control the progress of the polymerization reaction and that apparatuses widely used in the field as photopolymerization apparatuses can be used. Therefore, it is preferable to select the type of the polymerizable smectic liquid crystal compound or photopolymerization initiator contained in the polarizing layer forming composition so that it can be photopolymerized by ultraviolet light. Moreover, when superposing | polymerizing, superposition | polymerization temperature can also be controlled by cooling a dry film with a suitable cooling means with ultraviolet light irradiation. By adopting such a cooling means, if the polymerizable smectic liquid crystal compound can be polymerized at a lower temperature, the polarizing film can be appropriately formed even if the above-mentioned transparent substrate has a relatively low heat resistance. There is also an advantage.

  By performing photopolymerization as described above, the polymerizable smectic liquid crystal compound is polymerized while maintaining the liquid crystal state of a smectic phase, preferably a higher-order smectic phase as exemplified above, and this polarizing film is formed. Is done. This polarizing film obtained by polymerizing a polymerizable smectic liquid crystal compound while maintaining the liquid crystal state of the smectic phase is a conventional host-guest type polarizing film, that is, a nematic phase, due to the action of the azo dye (1). As compared with a polarizing film obtained by polymerizing a polymerizable liquid crystal compound while maintaining the liquid crystal state, there is an advantage that the polarizing performance is much higher.

  The thickness of the polarizing film is preferably in the range of 0.5 μm to 10 μm, and more preferably 1 μm to 5 μm. Therefore, the thickness of the coating film for forming the present polarizing film is determined in consideration of the thickness of the obtained present polarizing film. In addition, the thickness of this polarizing film is calculated | required by the measurement of an interference film thickness meter, a laser microscope, or a stylus-type film thickness meter.

  The polarizing film thus formed comprises at least two dichroic dyes having different maximum absorption wavelengths, preferably at least two azo dyes (1), particularly preferably azo dyes (1 The composition for forming a polarizing film containing a combination of () has an absorption spectrum that satisfies the relationships of the above formulas (I) to (V). In particular, if a composition containing a combination of the azo dyes (1) shown in Table 1 is used as the composition for forming a polarizing film, the absorption that satisfies the relationships of the above formulas (I) to (V) can be more easily achieved. The present polarizing film having a spectrum can be obtained.

  Moreover, it is particularly preferable that the polarizing film thus formed has a Bragg peak in X-ray reflection measurement. As this polarizing film from which such a Bragg peak is obtained, for example, the present polarizing film showing a diffraction peak derived from a hexatic phase or a crystal phase can be mentioned.

Further, the polarizing film preferably has a visibility correction single transmittance Ty of 43% or more and a visibility correction single polarization Py of 90% or more. Here, the visibility correction single transmittance Ty and the visibility correction single polarization Py are the transmittance (T ¹ ) in the transmission axis direction and the transmittance in the absorption axis direction of the polarizing film in the wavelength range of 300 to 800 nm. (T ² ) is measured, the single transmittance and the degree of polarization are calculated using the following formula (VI) and formula (VII), and the visibility correction is performed with the two-degree field of view (C light source) of JIS Z8701. is there.
Ty (%) = (T ¹ + T ² ) / 2 Formula (VI)
Py (%) = {(T ¹ −T ² ) / (T ¹ + T ² )} × 100 Formula (VII)

<Continuous manufacturing method of this polarizing film (this circular polarizing plate)>
As mentioned above, although the outline | summary of the manufacturing method of this polarizing film was demonstrated, when manufacturing this polarizing film commercially, the method which can manufacture this polarizing film continuously is calculated | required. Such a continuous manufacturing method is based on the Roll to Roll format, and is sometimes referred to as “the present manufacturing method”. In the present manufacturing method, the case where a transparent base material imparted with retardation is used as the base material will be mainly described.

This manufacturing method is, for example,
Preparing a first roll in which a transparent substrate is wound around a first core;
Continuously feeding the transparent substrate from the first roll;
Applying a composition containing a polymer having a photoreactive group and a solvent, and continuously forming a first coating film on the transparent substrate;
A step of drying and removing the solvent from the first coating film to form a first dry film on the transparent substrate to obtain a first laminate continuously;
Irradiating the first dry film with polarized UV to form a photo-alignment layer and continuously obtaining a second laminate;
Applying a composition containing a polymerizable smectic liquid crystal compound, a dichroic dye and a solvent on the photo-alignment layer, and continuously forming a second coating film on the photo-alignment layer; The coating film is dried under the condition that the polymerizable smectic liquid crystal compound contained in the second coating film is not polymerized to form a second dry film on the photo-alignment layer, thereby continuously forming the third laminate. A process of obtaining
After making the polymerizable smectic liquid crystal compound contained in the second dry film into a smectic liquid crystal state, the polarizing film is continuously formed by polymerizing the polymerizable smectic liquid crystal compound while maintaining the smectic liquid crystal state. Obtaining a step;
A step of winding the continuously obtained polarizing film around a second core to obtain a second roll. Here, with reference to FIG. 1, the principal part of this manufacturing method is demonstrated.

  The first roll 210 in which the transparent base material is wound around the first core 210A can be easily obtained from the market, for example. Examples of the transparent substrate that can be obtained from the market in the form of such a roll include a film made of cellulose ester, cyclic olefin resin, polyethylene terephthalate, polycarbonate, or polymethacrylic acid ester, among the already exemplified transparent substrates. . In addition, a transparent base material imparted with retardation, which can be used when the polarizing film is obtained in the form of a circularly polarizing plate, can be easily obtained from the market, for example, cellulose ester, polycarbonate, or cyclic olefin resin. The retardation film which consists of is mentioned.

  Subsequently, the transparent substrate is unwound from the first roll 210. The method for unwinding the transparent substrate is performed by installing an appropriate rotating means on the core 210A of the first roll 210 and rotating the first roll 210 by the rotating means. Alternatively, a suitable auxiliary roll 300 may be installed in the direction of transporting the transparent base material from the first roll 210 and the transparent base material may be unwound by the rotating means of the auxiliary roll 300. Further, the first winding core 210A and the auxiliary roll 300 may be provided with a rotating means so that the transparent substrate is unwound while applying an appropriate tension to the transparent substrate.

  When the transparent base material unwound from the first roll 210 passes through the coating device 211A, the alignment film forming composition is applied onto the surface of the transparent base material by the coating device 211A. As described above, in order to continuously apply the alignment film forming composition as described above, the coating apparatus 211A is a printing method such as a gravure coating method, a die coating method, or a flexo method.

  The film that has passed through the coating device 211A corresponds to a laminate of the transparent substrate and the first coating film. Thus, the transparent base material on which the first coating film is formed (laminated) is conveyed to the drying furnace 212A and heated by the drying furnace 212A to the first laminated body including the transparent base material and the first dry film. And convert. For example, a hot air drying furnace or the like is used as the drying furnace 212A. The set temperature of the drying furnace 212A is determined according to the type of the solvent contained in the alignment film forming composition applied by the coating apparatus 211A. The drying furnace 212A may be divided into appropriate zones, and the set temperature may be different for each of the divided zones. A plurality of drying furnaces are arranged in series, and each drying is performed at different set temperatures. The film may be sequentially conveyed through the plurality of drying furnaces while the furnace is operated.

  The first laminate continuously formed by passing through the heating furnace 212A is subsequently polarized on the surface of the laminate on the first dry film side or the transparent substrate side by the polarized UV irradiation device 213A. When UV is irradiated, the first dry film is converted into a light polarizing layer. At that time, the angle formed by the film transport direction D1 and the alignment direction D2 of the formed photo-alignment layer is set to approximately 45 °. FIG. 2 is a diagram schematically showing the relationship between the orientation direction D2 of the photo-alignment layer formed after irradiation with polarized UV light and the film transport direction D1. That is, FIG. 1 shows that when the surface of the first laminate after passing through the polarized UV irradiation device 213A is viewed in the film transport direction D1 and the alignment direction D2 of the photo-alignment layer, the angle between them is approximately 45 °. Indicates that

  Thus, after the 1st laminated body formed continuously passes the coating device 211B and the composition for polarizing film formation is apply | coated on the photo-alignment layer of this 1st laminated body, drying furnace 212B The polymerizable smectic liquid crystal compound contained in the second laminate or the second dry film of the second laminate becomes a laminate in which a smectic liquid crystal state is formed. The drying furnace 212B serves to dry and remove the solvent from the polarizing film forming composition applied on the photo-alignment layer, and the polymerizable smectic liquid crystal compound contained in the second dry film is in a smectic phase liquid crystal state. As such, it plays a role of giving thermal energy to the second dry film. In addition, as described above, in order to make the polymerizable smectic liquid crystal compound into a smectic phase liquid crystal state, in order to make the polymerizable smectic liquid crystal compound into a nematic phase liquid crystal state, It is necessary to perform multi-stage heat treatment on the first laminated body under different heating conditions. Therefore, as described in the drying furnace 212A, the drying furnace 212B is composed of a plurality of zones having different set temperatures or a plurality of drying furnaces having different set temperatures, and the plurality of drying furnaces are connected in series. It is preferable to be in the form of installation.

  The film that has passed through the drying oven 212B is sufficiently irradiated with light while the solvent contained in the polarizing layer forming composition is sufficiently removed and the polymerizable smectic liquid crystal compound in the second dry film maintains the liquid crystal state of the smectic phase. It is conveyed to the device 213B. By the light irradiation by the light irradiation device 213B, the polymerizable smectic liquid crystal compound is photopolymerized while maintaining the liquid crystal state, and the polarizing film is continuously formed on the alignment film.

  The polarizing film thus continuously formed is wound around the second core 220A in the form of a laminate including the transparent base material and the alignment film, and the form of the second roll 220 is obtained. When the formed polarizing film is wound up to obtain the second roll, winding using an appropriate spacer may be performed.

  In this way, the transparent base material passes through the first roll / coating apparatus 211A / drying furnace 212A / polarized UV irradiation apparatus 213A / coating apparatus 211B / drying furnace 212A / light irradiation apparatus 213A in this order. The polarizing film is continuously produced on the upper photo-alignment layer.

  In addition, in the present manufacturing method shown in FIG. 1, a method of continuously manufacturing from the transparent base material to the present polarizing film is shown. For example, the transparent base material is a first roll / coating device 211A / drying furnace 212A / By passing the polarized UV irradiation device 213A in this order, the first laminated body formed continuously is wound around the core, and the first laminated body is manufactured in the form of a roll, and the first laminated body is produced from the roll. The polarizing film may be manufactured by passing the unwound first laminated body through the coating device 211B / drying furnace 212A / light irradiation device 213A in this order.

  As mentioned above, the configuration and the manufacturing method of the polarizing film have been described mainly with respect to the case of the laminate of the transparent substrate / the photo-alignment layer / the polarizing film. The photo-alignment layer and the transparent substrate may be peeled from the body, or a layer or film other than the transparent substrate / photo-alignment layer / main polarizing film may be laminated on the laminate. As these layers and films, as described above, the polarizing film may further include a retardation film, or may further include an antireflection layer or a brightness enhancement film.

  Moreover, it can also be set as the circularly-polarizing plate or elliptical polarizing plate of the form of retardation film / photo-alignment layer / this polarizing film by making transparent substrate itself into retardation film. For example, when a uniaxially stretched quarter-wave plate is used as the retardation film, by setting the irradiation direction of polarized UV to be approximately 45 ° with respect to the transport direction of the transparent substrate, Roll-to It is possible to produce a circularly polarizing plate with -Roll. Thus, it is preferable that the quarter wavelength plate used when manufacturing the circularly polarizing plate has a characteristic that the in-plane retardation value with respect to visible light becomes smaller as the wavelength becomes shorter.

  Further, using a half-wave plate as a retardation film, a linear polarizing plate roll was prepared in which the angle between the slow axis and the absorption axis of the polarizing film was shifted, and the surface on which the polarizing film was formed; It is possible to form a broadband circularly polarizing plate by further forming a quarter wavelength plate on the opposite side.

  In the present manufacturing method described above, the transparent base material may be replaced with a base material having no phase difference. In this case, in order to produce the present circularly polarizing plate, first, from the laminate of the base material (having no phase difference) / the photo-alignment layer / the present polarizing film obtained after the implementation of the present production method, the present polarizing film Is peeled to form a wound body 225. On the other hand, a winding body 230 on which the retardation film is wound is prepared. The present circularly polarizing plate can be produced by continuously unwinding the polarizing film from the wound body 225 and the retardation film from the wound body 230 and bonding them together by an appropriate method. The main part of this method is shown in FIG. Also in this case, it may be pasted so as to be approximately 45 ° with respect to the orientation direction of the retardation film and the present polarizing film. When the polarizing film and the retardation film are bonded, an appropriate adhesive is used, and the polarizing film and the retardation film are bonded via an adhesive layer formed from the adhesive. May be combined.

  In addition, when the polarizing film manufactured by the manufacturing method is required to have an absorption spectrum satisfying the relations of the above formulas (I) to (V), the polarizing film is formed as a single film by peeling off the transparent substrate. The absorption spectrum of the single polarizing film can be measured by a conventional method. For example, an absorption spectrum of a transparent substrate is measured in advance, and the absorption spectrum of the transparent substrate is used as a base. As a line, a method of measuring the absorption spectrum of the present polarizing film as formed on a transparent substrate or the like, or measuring an absorption spectrum of a transparent substrate in advance, followed by a transparent substrate Measure the absorption spectrum of the present polarizing film as formed on the transparent substrate, etc., and calculate the difference between the absorption spectrum of the present polarizing film as formed on the transparent substrate and the absorption spectrum of the transparent substrate. You can ask for it . By using these means for measuring the absorption spectrum of a transparent substrate or the like in advance, the absorption spectrum of the polarizing film can be easily obtained without removing the transparent substrate or the like.

<Application of this polarizing film>
This polarizing film makes it possible to produce this circularly polarizing plate that is extremely useful for organic EL (electroluminescence) display devices. The display device may be an inorganic electroluminescence (EL) display device.

  4 and 6 are schematic views schematically showing a cross-sectional configuration of an EL display device using the present polarizing film (hereinafter sometimes referred to as “the present organic EL display device”).

  The organic EL display device 30 using the polarizing film will be described with reference to FIG. When using this polarizing film for this organic EL display device, it is preferable to use this polarizing film after making it into a circularly polarizing plate (hereinafter, referred to as “this circularly polarizing plate” in some cases). There are two embodiments of this circularly polarizing plate. Therefore, before describing the configuration of the organic EL display device 30 and the like, two embodiments of the present circularly polarizing plate will be described with reference to FIG.

  FIG. 5A is a cross-sectional view schematically showing the first embodiment of the circularly polarizing plate 110. The first embodiment is a circular polarizing plate 110 in which a retardation layer (retardation film) 4 is further provided on the polarizing film 3. FIG. 6B is a cross-sectional view schematically showing a second embodiment of the circularly polarizing plate 110. In the second embodiment, a transparent base material (retardation film) to which a phase difference is imparted in advance is used as the transparent base material 1 used when the polarizer is manufactured. This is a circularly polarizing plate 110 having a function as the retardation layer 4.

  In the organic EL display device 30, an organic functional layer 36 that is a light source and a cathode electrode 37 are laminated on a substrate 33 on which a pixel electrode 35 is formed. A circularly polarizing plate 31 is disposed on the opposite side of the organic functional layer 36 across the substrate 33, and the circularly polarizing plate 110 is used as the circularly polarizing plate 31. By applying a positive voltage to the pixel electrode 35 and a negative voltage to the cathode electrode 37 and applying a direct current between the pixel electrode 35 and the cathode electrode 37, the organic functional layer 36 emits light. The organic functional layer 36 that is a light emitting source includes an electron transport layer, a light emitting layer, a hole transport layer, and the like. The light emitted from the organic functional layer 36 passes through the pixel electrode 35, the interlayer insulating film 34, the substrate 33, and the circularly polarizing plate 31 (this circularly polarizing plate 110). Although the organic EL display device having the organic functional layer 36 will be described, the present invention may be applied to an inorganic EL display device having an inorganic functional layer.

  In order to manufacture the organic EL display device 30, first, the thin film transistor 40 is formed in a desired shape on the substrate 33. Then, an interlayer insulating film 34 is formed, and then a pixel electrode 35 is formed by sputtering and patterned. Thereafter, the organic functional layer 36 is laminated.

  Next, the circularly polarizing plate 31 (the present circularly polarizing plate 110) is provided on the surface of the substrate 33 opposite to the surface on which the thin film transistor 40 is provided.

  When this circularly polarizing plate 110 is used as the circularly polarizing plate 31, the stacking order will be described with reference to an enlarged view of a portion C surrounded by a dotted line in FIG. When the circular polarizing plate 110 is used as the circular polarizing plate 31, the retardation layer 4 in the circular polarizing plate 110 is disposed on the substrate 33 side. (C1) in FIG. 9 is an enlarged view in which the first embodiment of the circularly polarizing plate 110 is used as the circularly polarizing plate 31, and (C2) in FIG. 9 shows the second embodiment of the circularly polarizing plate 110. 3 is an enlarged view used as a circularly polarizing plate 31. FIG.

  Next, members other than the main polarizing film 31 (circular polarizing plate 110) of the organic EL display device 30 will be briefly described.

  Examples of the substrate 33 include a sapphire glass substrate, a quartz glass substrate, a soda glass substrate and a ceramic substrate such as alumina; a metal substrate such as copper; a plastic substrate. Although not shown, a heat conductive film may be formed on the substrate 33. Examples of the thermally conductive film include a diamond thin film (DLC or the like). When the pixel electrode 35 is a reflection type, light is emitted in the opposite direction to the substrate 33. Therefore, not only a transparent material but also a non-permeable material such as stainless steel can be used. A single substrate may be formed, or a plurality of substrates may be bonded together with an adhesive to form a laminated substrate. Further, these substrates are not limited to plate-like ones, and may be films.

  For example, a polycrystalline silicon transistor may be used as the thin film transistor 40. The thin film transistor 40 is provided at the end of the pixel electrode 35 and has a size of about 10 to 30 μm. The size of the pixel electrode 35 is about 20 μm × 20 μm to 300 μm × 300 μm.

  On the substrate 33, wiring electrodes of the thin film transistor 40 are provided. The wiring electrode has a low resistance and has a function of suppressing resistance by being electrically connected to the pixel electrode 35. In general, the wiring electrode includes Al, Al and transition metals (except for Ti), Ti or Those containing any one or more of titanium nitride (TiN) are used.

An interlayer insulating film 34 is provided between the thin film transistor 40 and the pixel electrode 35. The interlayer insulating film 34 is formed by sputtering or vacuum deposition of an inorganic material such as silicon oxide such as SiO ₂ or silicon nitride, a silicon oxide layer formed by SOG (spin-on-glass), a photoresist, a polyimide. In addition, any film may be used as long as it has insulating properties, such as a coating film of a resin material such as an acrylic resin.

  A rib 41 is formed on the interlayer insulating film 34. The rib 41 is disposed in the peripheral portion (between adjacent pixels) of the pixel electrode 35. Examples of the material of the rib 41 include acrylic resin and polyimide resin. The thickness of the rib 41 is preferably 1.0 μm or more and 3.5 μm, more preferably 1.5 μm or more and 2.5 μm or less.

  Next, an EL element including a pixel electrode 35 that is a transparent electrode, an organic functional layer 36 that is a light emission source, and a cathode electrode 37 will be described. Each of the organic functional layers 36 includes at least one hole transport layer and a light emitting layer, and for example, sequentially includes an electron injection transport layer, a light emitting layer, a hole transport layer, and a hole injection layer.

Examples of the pixel electrode 35 include ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), IGZO, ZnO, SnO _2, and In ₂ O _3. ITO and IZO are particularly preferable. The pixel electrode 35 only needs to have a certain thickness or more that can sufficiently inject holes, and is preferably about 10 to 500 nm.
The pixel electrode 35 can be formed by an evaporation method (preferably a sputtering method). The sputtering gas is not particularly limited, and an inert gas such as Ar, He, Ne, Kr and Xe, or a mixed gas thereof may be used.

As a constituent material of the cathode electrode 37, for example, metal elements such as K, Li, Na, Mg, La, Ce, Ca, Sr, Ba, Al, Ag, In, Sn, Zn, and Zr may be used. In order to improve the operational stability of the electrode, it is preferable to use a two-component or three-component alloy system selected from the exemplified metal elements. Examples of the alloy system include Ag · Mg (Ag: 1 to 20 at%), Al·Li (Li: 0.3 to 14 at%), In · Mg (Mg: 50 to 80 at%), and Al · Ca (Ca: 5 to 20 at%) is preferable.
The cathode electrode 37 is formed by vapor deposition or sputtering. The thickness of the cathode electrode 37 is 0.1 nm or more, preferably 1 to 500 nm or more.

The hole injection layer has a function of facilitating the injection of holes from the pixel electrode 35, and the hole transport layer has a function of transporting holes and a function of blocking electrons. Also called transport layer.
The thickness of the light-emitting layer, the combined thickness of the hole injection layer and the hole transport layer, and the thickness of the electron injection / transport layer are not particularly limited and may vary depending on the formation method, but should be about 5 to 100 nm. Is preferred. Various organic compounds can be used for the hole injection layer and the hole transport layer. For the formation of the hole injecting and transporting layer, the light emitting layer and the electron injecting and transporting layer, a vacuum deposition method can be used in that a homogeneous thin film can be formed.

  Examples of the organic functional layer 36 that is a light emission source include those that use light emission (fluorescence) from singlet excitons, those that use light emission (phosphorescence) from triplet excitons, and those from singlet excitons. Including those using luminescence (fluorescence) and those using triplet excitons (phosphorescence), those formed with organic matter, those formed with organic matter and those formed with inorganic matter , A high molecular material, a low molecular material, a high molecular material and a low molecular material, and the like can be used. However, the organic functional layer 36 using various known materials for EL elements can be used for the organic EL display device 30 without being limited thereto.

  A desiccant 38 is disposed in the space between the cathode electrode 37 and the sealing lid 39. This is because the organic functional layer 36 is vulnerable to humidity. Moisture is absorbed by the desiccant 38 to prevent the organic functional layer 36 from deteriorating.

FIG. 6 is a schematic diagram illustrating a cross-sectional configuration of another aspect of the organic EL display device 30. This organic EL display device 30 has a sealing structure using a thin film sealing film 41, and can obtain emitted light from the opposite surface of the array substrate.
As the thin film sealing film 41, it is preferable to use a DLC film obtained by evaporating DLC (diamond-like carbon) on an electrolytic capacitor film. The DLC film has a characteristic that moisture permeability is extremely poor, and has high moisture-proof performance. Further, a DLC film or the like may be directly deposited on the surface of the cathode electrode 37. Further, the thin film sealing film 41 may be formed by laminating a resin thin film and a metal thin film in multiple layers.

  As described above, a novel organic EL display device including the novel polarizing film (the present polarizing film) according to the present invention and the present circularly polarizing plate including the present polarizing film is provided.

When the present organic EL display device includes the present circular polarizing plate including the present polarizing film, the intensity of light having a wavelength of 450 nm is I450, the intensity of light having a wavelength of 550 nm is I550, and the intensity of light having a wavelength of 650 nm is I650. ,
1 ≦ I450 / I550 <2 (X)
1 ≦ A450 / A650 <2 (XI)
It has an emission spectrum that satisfies all of the relationships indicated by. In the present organic EL display device, the polarizing film hardly absorbs light from the organic EL light emitting element, particularly blue light having a short lifetime (light emitting element having a wavelength of about 450 nm), so that the light emission intensity of the organic EL light emitting element is reduced. The lifetime of the organic EL image display device can be increased without the need to increase it. Therefore, the present polarizing film and the present circular polarizing plate have extremely high industrial value.

  Hereinafter, the present invention will be described in more detail with reference to examples. Unless otherwise specified, “%” and “parts” in the examples are% by mass and parts by mass.

In this example, the following polymerizable liquid crystal compound was used.
Compound (2-6) (compound represented by the following formula (2-6))
Compound (2-6) was prepared according to Lub et al. Recl. Trav. Chim. It was synthesized by the method described in Pays-Bas, 115, 321-328 (1996).

(Measurement of phase transition temperature)
The phase transition temperature of the compound (2-6) was confirmed by determining the phase transition temperature of the film made of the compound (2-6). The operation is as follows.
A film made of the compound (2-6) was formed on the glass substrate on which the alignment film was formed, and the phase transition temperature was confirmed by texture observation with a polarizing microscope (BX-51, manufactured by Olympus Corporation) while heating. The film composed of the compound (2-6) is heated to 120 ° C., and when the temperature is lowered, the film transitions to the nematic phase at 112 ° C., the phase transition to the smectic A phase at 110 ° C., and the smectic B phase at 94 ° C. It was confirmed that the phase transition occurred.

Compound (2-8) (compound represented by the following formula (2-8))
Compound (2-8) was synthesized with reference to the synthesis of compound (2-6) described above.

(Measurement of phase transition temperature)
The phase transition temperature of compound (2-8) was confirmed in the same manner as in the measurement of the phase transition temperature of compound (2-6). Compound (2-8) had a temperature transition to 140 ° C., a temperature transition to a nematic phase at 131 ° C., a phase transition to a smectic A phase at 80 ° C., and a phase transition to a smectic B phase at 68 ° C. It was confirmed.

化合物（１−２１） ２．５部

重合開始剤；
２−ジメチルアミノ−２−ベンジル−１−（４−モルホリノフェニル）ブタン−１−オン（イルガキュア３６９；チバ スペシャルティケミカルズ社製） ６部
レベリング剤；
ポリアクリレート化合物（ＢＹＫ−３６１Ｎ；ＢＹＫ−Ｃｈｅｍｉｅ社製）
１．２部
溶剤；キシレン ２５０部 Example 1
(Preparation of composition for forming polarizing layer)
The components shown in Table 3 were mixed and stirred at 80 ° C. for 1 hour to obtain a composition for forming a polarizing layer. The structure and composition of each component (see Table 3 for the composition of the dichroic dye) are as follows.
Polymerizable liquid crystal compound; compound (2-6) 90 parts
Compound (2-8) 10 parts Dichroic dye;
Compound (1-5) 2.5 parts

Compound (1-21) 2.5 parts

A polymerization initiator;
2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals) 6 parts Leveling agent;
Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)
1.2 parts solvent; xylene 250 parts

(Measurement of phase transition temperature)
Similarly to the case of compound (2-6) and compound (2-8), the phase transition temperature of the polymerizable liquid crystal composition contained in the polarizing layer forming composition prepared as described above was determined. This polymerizable liquid crystal composition had a temperature transition to 140 ° C., a phase transition to a nematic phase at 116 ° C., a phase transition to a smectic A phase at 107 ° C., and a phase transition to a smectic B phase at 76 ° C. It was confirmed.

[Production and evaluation of this polarizing film]
1. Formation of alignment layer A glass substrate was used as a transparent substrate.
On the glass substrate, a 2% by weight aqueous solution (composition for forming an alignment layer) of polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified type, manufactured by Wako Pure Chemical Industries, Ltd.) was applied by spin coating, dried, and then thickened. A 100 nm thick film was formed. Subsequently, an alignment layer was formed by subjecting the surface of the obtained film to a rubbing treatment. The rubbing process uses a semi-automatic rubbing apparatus (trade name: LQ-008, manufactured by Joyo Engineering Co., Ltd.) and a push-in amount of 0.15 mm using a cloth (trade name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.). , Under the conditions of 500 rpm and 16.7 mm / s. By this rubbing treatment, a laminate 1 having an alignment layer formed on a glass substrate was obtained.

2. Formation of Polarizing Film The polarizing layer forming composition is applied onto the alignment layer of the laminate 1 by spin coating, heated and dried on a 120 ° C. hot plate for 1 minute, and then quickly cooled to room temperature. A dry film was formed on the alignment layer. In such a dry film, the liquid crystal state of the polymerizable liquid crystal composition (polymerizable liquid crystal compound) contained was a smectic B phase. Next, using a UV irradiation device (SPOT CURE SP-7; manufactured by USHIO INC.) Under a nitrogen atmosphere, the dried coating film is irradiated with ultraviolet rays at an exposure amount of 2000 mJ / cm ² (365 nm standard) to thereby dry the film. The polymerizable liquid crystal compound contained in the film was polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal composition, and a polarizing film was formed from the dried film. When the thickness of the polarizing film at this time was measured with a laser microscope (OLS3000 manufactured by Olympus Corporation), it was 1.8 μm.

4). Absorbance and transmittance measurement In order to confirm the usefulness of the present polarizer, the absorbance was measured as follows. The absorbance in the direction of the transmission axis (A ¹ ) and the absorbance in the direction of the absorption axis (A ² ) were measured by the double beam method using an apparatus in which a folder with a polarizer was set in a spectrophotometer (Shimadzu Corporation UV-3150). The spectrum was measured in the wavelength range of 300 to 800 nm. The folder was provided with a mesh that cuts the light amount by 50% on the reference side. The values of absorbance A450, A550, A650 and absorbance ratios A450 / A550 and A450 / A650 in the absorption axis direction at wavelengths of 450 nm, 550 nm, and 650 nm were determined. In this spectrum measurement, the absorption spectrum of the laminate 1 for forming the polarizing film was measured in advance, and corrected by using the absorption spectrum as a baseline.
Moreover, the visibility correction | amendment polarization degree (Py) and the visibility correction | amendment transmittance | permeability (Ty) which were calculated from the same spectrum result were calculated | required. These measurement results are shown in Table 2. Note that the visibility correction polarization degree (Py) and the visibility correction transmittance (Ty) are the transmittance (T ¹ ) in the transmission axis direction and the transmittance (T ² ) in the absorption axis direction in the wavelength range of 300 to 800 nm. It is a value obtained by measuring, calculating the single transmittance and the degree of polarization using the following formula (VI) and formula (VII), and correcting the visibility with a 2 degree visual field (C light source) of JIS Z8701.
Ty (%) = (T ¹ + T ² ) / 2 Formula (VI)
Py (%) = {(T ¹ −T ² ) / (T ¹ + T ² )} × 100 Formula (VII)

  In Examples 2 to 8, polarizing films were prepared in the same manner as in Example 1 except that the type of dichroic dye was changed. Table 1 shows the results of the addition amount of the dichroic dye and the thickness of the produced polarizing film. Similarly, an absorption spectrum was measured. The values of absorbance A450, A550, A650 and absorbance ratios A450 / A550, A450 / A650 in the absorption axis direction at wavelengths of 450 nm, 550 nm, and 650 nm were measured. Similarly, Table 4 shows the measurement results of the visibility correction polarization degree (Py) and the visibility correction transmittance (Ty).

Reference example 1
[Production of iodine PVA polarizing plate]
A polyvinyl alcohol film having an average degree of polymerization of about 2400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm is uniaxially stretched about 5.5 times in a dry manner and further maintained at 60 ° C. with pure water at 60 ° C. And then immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 20 seconds. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Subsequently, the film was washed with pure water at 26 ° C. for 20 seconds and then dried at 65 ° C. to obtain a polarizing film in which iodine was adsorbed and oriented on a polyvinyl alcohol resin.
On both sides of the polarizer thus obtained, 3 parts of carboxyl group-modified polyvinyl alcohol [Kuraray Co., Ltd., Kuraray Poval KL318] and a water-soluble polyamide epoxy resin [Sumika Chemtex Co., Ltd., Sumire's Resin 650 (solid content) 30% strength aqueous solution)] Polarized film with both sides protected by a saponified triacetyl cellulose film [KC8UX2MW manufactured by Konica Minolta Opto, Inc.] via a polyvinyl alcohol adhesive prepared from 1.5 parts Was made.

Reference example 2
A polarizing film was produced in the same manner as in Comparative Example 1 except that it was immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 35 seconds.
In the same manner as in Example 1, spectrum measurement was performed on the polarizing film thus prepared. Measurement of absorbances A450, A550, A650, absorbance ratios A450 / A550, A450 / A650 in the absorption axis direction at wavelengths of 450 nm, 550 nm, and 650 nm, as well as values of visibility corrected polarization (Py) and visibility corrected transmittance (Ty) The results are shown in Table 4.

Example 9
[Preparation of photo-alignment layer on retardation film]
Using a retardation film (uniaxially stretched film WRF-S (modified polycarbonate resin), retardation value 137.5 nm, thickness 50 μm, manufactured by Teijin Chemicals Ltd.) as a transparent substrate, a photo-alignment polymer of the following formula (3) A solution obtained by dissolving 5% in xylene was applied by a bar coating method and dried at 120 ° C. to obtain a dry film. On this dried film, polarized UV was irradiated in the direction of 45 ° with respect to the slow axis of the retardation film to obtain a photo-alignment film. The polarized UV treatment was performed using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO INC.) Under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ.

[Production of circularly polarizing plate]
On the photo-alignment film, the polarizing layer forming composition prepared in Example 1 was applied by a bar coating method, dried by heating in a 120 ° C. drying oven for 1 minute, and then cooled to room temperature. In such a dried film, the liquid crystal state of the polymerizable liquid crystal compound contained was a smectic B phase. Next, using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO INC.), The layer formed from the polarizing layer forming composition is irradiated with ultraviolet rays having an exposure amount of 2000 mJ / cm ² (365 nm standard). Thus, the polymerizable liquid crystal compound contained in the dry film was polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal compound, and a polarizing film was formed from the dry film. When the film thickness of the polarizing film at this time was measured with a laser microscope (OLS3000 manufactured by Olympus Corporation), it was 1.8 μm.

Example 10
A circularly polarizing plate was produced by conducting the same experiment as in Example 9, except that the polarizing layer forming composition prepared in Example 2 was used instead of the polarizing layer forming composition prepared in Example 1. .

Example 11
A circularly polarizing plate was produced by conducting the same experiment as in Example 9, except that the polarizing layer forming composition prepared in Example 8 was used instead of the polarizing layer forming composition prepared in Example 1. .

Reference example 3
Absorption axis of the polarizing film prepared in Reference Example 1 and retardation phase (uniaxially stretched film WRF-S (modified polycarbonate resin), retardation value 137.5 nm, thickness 50 μm, manufactured by Teijin Chemicals Limited) A circularly polarizing plate was produced by bonding with an adhesive so that the angle with the shaft was 45 °.

Reference example 4
Instead of the polarizing film prepared in Reference Example 1, the same experiment as in Reference Example 3 was performed except that the polarizing film prepared in Reference Example 2 was used, and a circularly polarizing plate was prepared.

<Measurement of optical properties>
The retardation films of the circularly polarizing plates obtained in Examples 9 to 10 and Reference Examples 3 to 4, respectively, and an aluminum metal plate are bonded via an adhesive, and the wavelength is the same as in the previous transmittance measurement. The reflectance at 450 nm, 550 nm, and 650 nm was measured. In addition, the visibility correction was performed by correcting the visibility using the two-degree field of view (C light source) of JIS Z8701. The results are shown in Table 4.
It turns out that the circularly-polarizing plate produced from this polarizing film has a favorable antireflection characteristic with respect to human visibility.

  The polarizing film is extremely useful for producing a liquid crystal display device, an (organic) EL display device, and a projection type liquid crystal display device.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Photo-alignment layer 3 This polarizing film 100 Polarizer 101 1st laminated body 102 2nd laminated body 103 3rd laminated body 210 1st roll 210A Core 220 Second roll 220A Core 211A, 211B Coating device 212A 212B Drying furnace 213A Polarized UV irradiation device 213B Light irradiation device 300 Auxiliary roll 30 EL display device 31 Polarizing film 32 Retardation film 33 Substrate 34 Interlayer insulating film 35 Pixel electrode 36 Light emitting layer 37 Cathode electrode 38 Desiccant 39 Sealing lid 40 Thin film transistor 41 Rib 42 Thin film sealing film 44 EL display device

Claims (6)

It is formed from a composition containing two or more dichroic dyes having different maximum absorption wavelengths and a polymerizable liquid crystal compound, and the content ratio of the polymerizable liquid crystal compound is from 70 to the solid content of the composition. 99.9 wt%, visibility correction single transmittance Ty is not less 43% or more, visibility correction alone polarization degree Py is polarizing film Ru der 90%
Having one orientation direction;
The following formulas (I) to (V)
0.3 ≦ A450 / A550 <0.8 (I)
0.3 ≦ A450 / A650 <1.0 (II)
0.5 ≦ A450 ≦ 2 (III)
1 ≦ A550 ≦ 3 (IV)
1 ≦ A650 ≦ 3 (V)
(Where
A450 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 450 nm,
A550 is the absorbance of polarized light parallel to the alignment direction at a wavelength of 550 nm,
A650 represents the absorbance of polarized light parallel to the alignment direction at a wavelength of 650 nm. )
A polarizing film having an absorption spectrum that satisfies all of the relationships indicated by. The polymerizable liquid crystal compound is the polarizing film according to claim 1 comprising a polymerizable smectic liquid crystal compound. The polarizing film according to claim 1 or 2, wherein both of the two or more dichroic dyes are polyazo dye materials represented by the following formula (1).

[In Formula (1),
n is 1 or 2.
Ar ₁ and Ar ₃ are each independently selected from the groups shown below.

Ar ₂ is selected from the following groups.

A ₁ and A ₂ are each independently selected from the groups shown below.

m is an integer of 0 to 10, and when there are two m's in the same group, these two m's are the same or different from each other. ]
It has the polarizing film in any one of Claims 1-3 , and (lambda) / 4 layer,
A circularly polarizing plate that satisfies the following requirements (A1) and (A2).
(A1) The angle formed by the absorption axis of the polarizing film and the slow axis of the λ / 4 layer is approximately 45 °;
(A2) The value of the front retardation of the λ / 4 layer measured with light having a wavelength of 550 nm is in the range of 100 to 150 nm. The value of front retardation of visible light of the lambda / 4 layers, circularly polarizing plate according to claim 4, further comprising a smaller characteristic as the wavelength becomes shorter. The organic EL display device having a circular polarizing plate according to claim 4 or 5, an organic EL element.

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