KR102129135B1 - Polarizing film, circular polarizing plate and method of producing the same - Google Patents

Abstract

An object of the present invention is to provide a polarizing film that is easy to thin and has excellent neutral color properties, a polarizer including the polarizing film, and a method of manufacturing the same.
A polymer formed of a polymerizable liquid crystal compound, and when the light absorption is measured by dispersing in the polymer, at least one dichroic dye (1) having a maximum absorption in a wavelength range of 380 to 550 nm and a wavelength of 550 to Provided is a polarizing film comprising at least two dichroic dyes 2 having a maximum absorption in the range of 700 nm, a polarizer comprising the polarizing film, and a method for manufacturing the same. It is preferable that the dichroic dye (2) includes a dichroic dye having absorption in the range of wavelengths of 550 to 600 nm and a dichroic dye having absorption in the range of wavelengths of 600 to 700 nm.

Description

Polarizing film, circular polarizing plate, and manufacturing method thereof {POLARIZING FILM, CIRCULAR POLARIZING PLATE AND METHOD OF PRODUCING THE SAME}

The present invention relates to a polarizing film, a circular polarizing plate, and a method for manufacturing them.

Since the polarizer used in the liquid crystal display device has both high transmittance and polarization degree, a film (polarizing film) made of polyvinyl alcohol (iodine dyed PVA) dyed and stretched with a dichroic dye such as iodine is widely used. have. For example, Patent Document 1 describes a polarizing film made of iodine-dyed PVA.

Patent Document 1: Japanese Patent Publication No. Hei 7-142170

However, the polarizing film made of iodine-dyed PVA tends to have a yellow energy, and there is a problem that the so-called neutral color property is inferior. In addition, since the polarizing film made of iodine-dyed PVA is difficult to thin, it has a limit to be applied to recent display devices requiring thinner thickness. Therefore, an object of the present invention is to provide a polarizing film that is easy to thin and has excellent neutral color properties, a polarizer comprising the polarizing film, and a method of manufacturing the same.

The present invention includes the following inventions.

[1] a polymer formed of a polymerizable liquid crystal compound and at least one dichroic dye (1) having a maximum absorption in the range of wavelength 380 to 550 nm when dispersed in the polymer to measure light absorption, A polarizing film comprising at least two dichroic dyes (2) having a maximum absorption in the range of wavelength 550 to 700 nm.

[2] Polarization according to [1], wherein the dichroic dye (1) has a maximum absorption in the range of 400 to 550 nm in wavelength when light absorption is measured by dispersing it in a polymer formed of a polymerizable liquid crystal compound. membrane.

[3] At the time of measuring the light absorption by dispersing in the polymer, at least two dichroic dyes (2) having a maximum absorption in the range of wavelength 550 to 700 nm,

When the light absorption is measured by dispersing in the polymer,

A dichroic dye (2-1) having a maximum absorption in a wavelength range of 550 to 600 nm,

The polarizing film according to [1] or [2], comprising a dichroic dye (2-2) having a maximum absorption in a range of 600 to 700 nm in wavelength.

[4] The polarizing film according to any one of [1] to [3], wherein the polymerizable liquid crystal compound is a compound exhibiting a smectic liquid crystal phase.

[5] The polarizing film according to any of [1] to [4], in which a Bragg peak is obtained in X-ray diffraction measurement.

[6] Any of [1] to [5], in which the color coordinate a* and b* values in the L*a*b* colorimeter satisfy the relationship of the following expressions (1F) and (2F): One polarizing film.

-3≤ Chromaticity a*≤3 (1F)

-3≤ Chromaticity b*≤3 (2F)

[7] The polarizing film according to any of [1] to [6], wherein the dichroic dye (1) and the dichroic dye (2) are azo compounds.

[8] The polarizing film according to any one of [1] to [7], wherein the dichroic dye (2) is composed of a compound represented by formula (2).

[In formula (2), n is 1 or 2.

Ar ¹ and Ar ³ are groups independently represented by any of formulas (AR-1) to (AR-4).

Ar ² is a group represented by formula (AR2-1), formula (AR2-2) or formula (AR2-3).

A ₁ and A ₂ are each independently a group represented by any of formulas (A-1) to (A-9), and * represents a bond number.

(mc is an integer from 0 to 10, and when there are two mcs in the same group, the two mcs are the same or different from each other.)]

[9] The polarizing film according to any one of [1] to [8], wherein the dichroic dye (1) is composed of a compound represented by formula (1).

[In Formula (1), Y is a group represented by Formula (Y1) or Formula (Y2).

(In the formula, L is an oxygen atom or -NR-, and R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

R ¹ is a group represented by any of formulas (R ¹ -1) to (R ¹ -3).

(In the formula, ma is an integer from 0 to 10, and when there are two ma in the same group, the two ma are the same or different from each other. * represents the number of bonds.)

R ² is a group represented by any of formulas (R ² -1) to (R ² -6).

(In the formula, mb is an integer from 0 to 10.)]

[10] A polarizer formed by forming the polarizing film according to any one of [1] to [9] on a transparent substrate.

[11] As a method of manufacturing the polarizer according to [10],

The process of preparing a laminated body provided with an alignment film on a transparent substrate,

A dichroic dye having an absorption maximum in the range of wavelength 380 to 550 nm when dispersed in a polymer formed of a polymerizable liquid crystal compound and a polymer formed of the polymerizable liquid crystal compound on the alignment layer of the laminate to measure light absorption. (1) a process of applying a composition comprising one type, two types of dichroic dyes (2) having absorption maxima in the range of wavelengths 550 to 700 nm, and a solvent,

A manufacturing method having a step of polymerizing the polymerizable liquid crystal compound contained in the composition.

[12] The production method according to [11], wherein the transparent substrate is a plastic substrate, and the alignment film is a photo-alignment film.

[13] A liquid crystal display device comprising the polarizing film according to any one of [1] to [9].

[14] A circular polarizing plate having the polarizing film and λ/4 layer according to any one of [1] to [9], and satisfying the requirements of (A1) and (A2) below.

(A1) the angle between the absorption axis of the polarizing film and the slow axis of the λ/4 layer should be approximately 45°;

(A2) The value of the front retardation of the λ/4 layer measured with light having a wavelength of 550 nm should be in the range of 100 to 150 nm

[15] An organic EL display device comprising the circular polarizing plate according to [14] and an organic EL element.

According to the present invention, it is possible to provide a polarizing film that is easy to thin and has excellent neutral color property, and a polarizer including the polarizing film.

1 is a schematic view of a method for continuously manufacturing a polarizer (this polarizer) comprising the polarizing film of the present invention.
It is a schematic diagram which shows the relationship between the orientation direction D2 of a photo-alignment film, and the conveyance direction D1 of a film.
3 is a schematic view showing a cross-sectional configuration of a liquid crystal display device using the polarizing film of the present invention.
FIG. 4 is a schematic diagram showing the layer order of the polarizer used in the liquid crystal display of FIG. 3.
5 is a schematic view showing the layer order of the present polarizer used in the liquid crystal display of FIG. 3.
6 is a schematic view showing a cross-sectional configuration of an EL display device using the polarizing film of the present invention.
It is a schematic diagram which shows the sectional structure of the embodiment of this polarizer containing the polarizing film of this invention.
8 is a schematic view showing an example of a method for continuously manufacturing a circular polarizing plate (this circular polarizing plate) containing the polarizing film of the present invention.
Fig. 9 is a schematic diagram showing the layer order of the original polarizing plate used in the EL display device of Fig. 6;
10 is a schematic view showing a cross-sectional configuration of an EL display device using the polarizing film of the present invention.
11 is a schematic view showing the configuration of a projection type liquid crystal display device using the polarizing film of the present invention.

The polarizing film of the present invention (hereinafter referred to as "this polarizing film" in some cases) is characterized by comprising a polymer formed of a polymerizable liquid crystal compound and three or more specific dichroic dyes. It is preferable that this polarizing film is formed from a composition containing a polymerizable liquid crystal compound and the above-mentioned three or more dichroic dyes (hereinafter referred to as "a composition for forming a polarizing film" in some cases). First, the composition for forming a polarizing film will be described.

1. Composition for forming polarizing film

The composition for forming a polarizing film of the present invention preferably contains a polymerizable liquid crystal compound and three or more specific dichroic dyes as described above, and further contains a solvent. The present polarizing film formed of the composition for forming such a polarizing film is easy to thin. First, each of the components included in the composition for forming a polarizing film will be described.

1-1. A dichroic pigment

The dichroic dye contained in the composition for forming a polarizing film is dispersed in a polymer formed of a polymerizable liquid crystal compound, and when light absorption is measured, at least one dichroic dye having a maximum absorption in the wavelength range of 380 to 550 nm In the same measurement as (1), at least two dichroic dyes 2 having absorption maxima in the range of wavelength 550 to 700 nm are included.

1-1-1. Dichroic pigment (1)

The dichroic dye 1 has a maximum absorption in the range of wavelength 380-550 nm when light absorption is measured by dispersing it in a polymer formed of a polymerizable liquid crystal compound. On the other hand, this measurement prepares a composition for measuring maximum absorption in which the dichroic dye of the composition for forming a polarizing film in the present invention is replaced with a dichroic dye for measuring maximum absorption, and for forming a polarizing film described later. The film for measuring the absorption maximum can be formed by the same method as the method for forming the present polarizing film with the composition, and the light absorption of the film for measuring the absorption maximum can be measured. The specific method of measuring the absorption maximum is the same as the method described in the Examples herein.

An azo compound is mentioned as a dichroic dye (1), for example. Preferably, the compound represented by Formula (1) (hereinafter referred to as “compound (1)” in some cases) is mentioned.

The geometric isomer of the azobenzene moiety of compound (1) is preferably trans.

Y in Formula (1) is a group represented by Formula (Y1) or Formula (Y2) described above, and is preferably a group represented by Formula (Y1). In formulas (Y1) and (Y2), the straight lines at both ends represent the number of bonds, the number of bonds on the left side is bonded to a phenylene group having an azo group, and the number of bonds on the right side is bonded to a phenylene group having R ² . have. L is an oxygen atom or -NR-, and R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group. Among them, L is preferably an oxygen atom or -NH-, and more preferably an oxygen atom.

R ¹ is a group represented by the above formula (R ¹ -1), formula (R ¹ -2) or formula (R ¹ -3), preferably formula (R ¹ -2) and formula (R ^1- It is a group represented by 3). Two ma in the group represented by the formula (R ¹ -2) may be the same or different, but preferably the same. More preferably, ma is an integer from 0 to 5.

R ² is the formula (R ² -1), the formula (R ² -2), the formula (R ² -3), the formula (R ² -4), the formula (R ² -5) or the formula (R ² -6) It is a group represented by, and is more preferably a group represented by formula (R ² -2), formula (R ² -5) or formula (R ² -6), and a group represented by formula (R ² -6) It is more preferable. When R ² is a group represented by formula (R ² -1), formula (R ² -2), formula (R ² -3), formula (R ² -5) or formula (R ² -6), The included mb is preferably an integer from 0 to 10, and more preferably an integer from 0 to 5.

Preferred compounds (1) include compounds represented by the following formulas (1-1) to (1-8).

Especially, the compound represented by Formula (1-1), Formula (1-2), Formula (1-3), Formula (1-5), Formula (1-7), and Formula (1-8) is preferable. , Compounds represented by formula (1-1), formula (1-2), formula (1-3) and formula (1-7) are particularly preferred.

The dichroic dye 1 has an absorption maximum in the wavelength range of 380 to 550 nm when light absorption is determined by the above measurement, and preferably has an absorption maximum in the range of wavelength 400 to 550 nm, and the wavelength 400 to 520 It is more preferable to have an absorption maximum in the range of nm, more preferably to have an absorption maximum in the range of wavelengths 430 to 520 nm, and particularly preferably to have an absorption maximum in the range of wavelengths 440 to 510 nm. As long as it has an absorption maximum in the above range, multiple types of compounds (1) can also be used as the dichroic dye (1).

Here, a method for producing compound (1) will be described. Compound (1) can be produced by, for example, a reaction represented by the following scheme with a compound represented by formula (1X) [compound (1X)] and a compound represented by formula (1Y) [compound (1Y)].

In the above scheme, R ¹ , R ² and Y have the same meaning as above, and Re ¹ and Re ² are groups that react with each other to be a group represented by Y. As the combination of Re ¹ and Re ² , for example, a combination of a carboxy group and a hydroxyl group, a combination of a carboxy group and an amino group (these amino groups may be substituted with R), a combination of a carbonyl halide group and a hydroxyl group, a carbonyl halide group and an amino group (these amino groups) Is a combination of R may be substituted), a combination of a carbonyloxyalkyl group and a hydroxyl group, a combination of a carbonyloxyalkyl group and an amino group (these amino groups may be substituted with R), and the like. In addition, although the compound (1X) having R ¹ and the compound (1Y) having R ² are described herein, a compound protected by R ¹ with a suitable protecting group or a compound protected with R ² by a suitable protecting group reacts with each other, and Thereafter, compound (1) can also be produced by performing an appropriate deprotection reaction.

Reaction conditions when reacting compound (1X) and compound (1Y) can be appropriately selected according to the type of compound (1X) and compound (1Y) to be used, and optimally known conditions can be selected.

For example, the reaction conditions when Re ¹ is a carboxy group, Re ² is a hydroxyl group, and Y is -C(=O)-O- include, for example, conditions for condensation in the presence of an esterified condensing agent in a solvent. Examples of the solvent include a solvent soluble in both compound (1X) such as chloroform and compound (1Y). Diisopropyl carbodiimide (IPC) etc. are mentioned as an esterified condensing agent. Here, it is preferable to use a base such as dimethylaminopyridine (DMAP) in combination. The reaction temperature is selected depending on the type of the compound (1X) and the compound (1Y). For example, a range of -15 to 70°C is mentioned, and preferably 0 to 40°C. The reaction time is, for example, in the range of 15 minutes to 48 hours.

The reaction time is appropriately sampled during the reaction, and the degree of loss of compound (1X) and compound (1Y) or the degree of production of compound (1) can be determined by known analytical means such as liquid chromatography and gas chromatography. It can also be determined by confirmation.

Compound (1) can be extracted from the reaction mixture after the reaction by known methods such as recrystallization, reprecipitation, extraction and various chromatography, or by combining these operations.

1-1-2. Dichroic pigment (2)

The dichroic dye 2 has an absorption maximum in the wavelength range of 550 to 700 nm when the above measurement is performed. The measurement method of absorption maximum is the same as that of the dichroic dye (1).

The dichroic dye (2) includes two or more types in the composition for forming a polarizing film. Among them, the dichroic dye (2-1) having a maximum absorption in the range of a wavelength of 550 to 600 nm and a wavelength of 600 to 700 nm It is more preferable to include the dichroic dye (2-2) having the maximum absorption in the range of. Here, the dichroic dye (2-1) is more preferable if it has an absorption maximum in the wavelength range of 570 to 600 nm, and the dichroic dye (2-2) is more preferable if it has an absorption maximum in the range of wavelength 600 to 680 nm. Do.

An azo compound is mentioned as a dichroic dye (2), for example. The dichroic dye (2) is preferably a compound represented by the formula (2) (hereinafter referred to as "compound (2)" in some cases).

Trans is preferred for the geometrical azobenzene moiety of compound (2).

In the combination of each group of the compound (2), the dichroic dye (2-) is obtained by combining Ar ¹ , Ar ² and Ar ^{3 such} that the compound (2) has an absorption maximum in the wavelength range of 550 to 600 nm in the measurement. Compound (2) which can be used as 1) is determined. As a specific dichroic dye (2-1), the compound (2) shown by combination of each group in Table 1 is mentioned. The compound (2-1) showing the combination of each group in Table 1 shows the case where n in Formula (2) is 1. On the other hand, in Table 1, for example, groups represented by formula (AR-1) are denoted by "(AR-1)" or the like.

Subsequently, in the combination of each group of the compound (2), the dichroic dye (2) is obtained by combining Ar ¹ , Ar ² and Ar ³ so that the compound (2) has absorption in the range of 600 to 700 nm in the measurement. Compound (2) which can be used as -2) is determined. As a specific dichroic dye (2-2), the compound (2) shown by combination of each group in Table 2 is mentioned. The compound (2-2) showing the combination of each group in Table 2 shows the case where n in Formula (2) is 1. Meanwhile, the notation of a group in Table 2 is the same as that of Table 1.

Here, when compound (2) is specifically shown, the compound etc. which are respectively represented by Formula (2-11)-Formula (2-39) are mentioned.

Among the specific examples of the compound (2) exemplified herein, as the dichroic dye (2-1), formulas (2-12), (2-13), (2-18), (2-20), Expression (2-21), Expression (2-22), Expression (2-23), Expression (2-24), Expression (2-26), Expression (2-27), Expression (2-28), Expression Corresponding to those represented by (2-29) and formula (2-30) respectively, and as the dichroic dye (2-2), formula (2-31), formula (2-32), formula (2-33), It corresponds to what is represented by Formula (2-34), Formula (2-35), and Formula (2-36), respectively. On the other hand, those represented by formulas (2-11), (2-15) and (2-16), respectively, are not pigments showing absorption at wavelengths of 550 to 700 nm, but are used in combination with the pigments of formula (1). can do.

Among the specific examples of the compound (2), as the dichroic dye (2) contained in the composition for forming a polarizing film, formula (2-15), formula (2-16), formula (2-18), formula (2-20) ), Expression (2-21), Expression (2-22), Expression (2-23), Expression (2-27), Expression (2-29), Expression (2-31), Expression (2-32) , It is more preferable that it is represented by Formula (2-33), Formula (2-34), and Formula (2-35), respectively. Among these, when the dichroic dye (2) is represented by a combination of two or more selected from the specific examples of the compound (2), it differs depending on the mixing ratio, but is shown in Table 3, for example. In Table 3, for example, the compound (2) represented by formula (2-11) is assumed to be represented by "(2-11)".

The content of the dichroic dye (1) in the composition for forming a polarizing film is expressed as a content with respect to 100 parts by mass of the polymerizable liquid crystal compound to be described later, preferably 50 parts by mass or less, more preferably 0.1 parts by mass or more and 10 parts by mass or less Preference is given to 0.1 parts by mass or more and 5 parts by mass or less.

The content of the dichroic dye (2) in the composition for forming a polarizing film is expressed as content relative to 100 parts by mass of the polymerizable liquid crystal compound to be described later, preferably 10 parts by mass or less, and more preferably 0.1 parts by mass or more and 5 parts by mass or less It is preferable, and 0.1 mass part or more and 3 mass parts or less are more preferable.

In addition, the total content of the dichroic dye (1) and the dichroic dye (2) in the composition for forming a polarizing film is expressed as a content with respect to 100 parts by mass of the polymerizable liquid crystal compound described later, preferably 30 parts by mass or less, 0.1 mass part or more and 20 mass parts or less are more preferable, and 1 mass part or more and 15 mass parts or less are more preferable.

When the content of each of the dichroic dyes is within the above range, the dichroic dyes in the composition for forming a polarizing film exhibit sufficient solubility in a solvent. It is possible to obtain the present polarizing film without occurrence of. On the other hand, as described above, the polarizing film-forming composition only needs to contain at least one dichroic dye (1) and two or more dichroic dyes (2), the polarizing film forming composition is a dichroic dye (1 ) Even if it contains 2 or more types, it may contain 3 or more types of dichroic dyes (2). When two or more types of dichroic dyes (1) are included, the content of the dichroic dyes (1) is the total amount of the two or more dichroic dyes (1), and when three or more of the dichroic dyes (2) are included , The content of the dichroic dye 2 is the total amount of three or more dichroic dyes 2.

The dichroic dye 2 is produced, for example, by a known method described in Japanese Patent Laid-Open No. 58-38756, No. 63-301850, No. 58-104984.

Next, constituent components other than the dichroic dye in the composition for forming a polarizing film will be described.

1-2. Polymerizable liquid crystal compounds

The polymerizable liquid crystal compound is a liquid crystal compound that can be polymerized while being oriented, and has a polymerizable group in the molecule. The composition for forming a polarizing film containing a polymerizable liquid crystal compound forms the present polarizing film by polymerizing the polymerizable liquid crystal compound in an aligned state. The polymerizable group is particularly preferable as long as it is a radical polymerizable group. The radical polymerizable group means a group involved in the radical polymerization reaction.

The polymerizable liquid crystal compound contained in the composition for forming a polarizing film of the present invention is a liquid crystal phase of a smectic phase (hereinafter, referred to as "nematic liquid crystal phase" in some cases). In some cases, it may be either a "smectic liquid crystal phase" or a nematic liquid crystal phase or a smectic liquid crystal phase, but is preferably a polymerizable smectic liquid crystal compound showing at least a smectic liquid crystal phase. The composition for forming a polarizing film containing a polymerizable smectic liquid crystal compound is a polarizing film having a very good neutral color property and more excellent polarization performance by the interaction of the dichroic dye (1) and the dichroic dye (2). Can be obtained.

As the smectic liquid crystal phase represented by the polymerizable smectic liquid crystal compound, a higher order smectic liquid crystal phase is more preferable. The higher order smectic liquid crystal phases referred to herein are smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, sm Smectic K phase and Smectic L phase, among them, Smectic B phase, Smectic F phase and Smectic I phase are more preferable.

If the smectic liquid crystal phase represented by the polymerizable liquid crystal compound is these higher order smectic liquid crystal phases, the present polarizing film with higher alignment order can be produced. In addition, in this X-ray diffraction measurement, this polarizing film produced from a high order smectic liquid crystal phase having a high degree of alignment is obtained with a Bragg peak derived from a high order structure such as a hexatic phase or a crystal phase. The Bragg peak is a peak derived from a molecularly oriented surface periodic structure, and according to the composition for forming a polarizing film of the present invention, a main polarizing film having a periodic interval of 3.0 to 5.0 kPa can be obtained.

Whether the polymerizable liquid crystal compound contained in the composition for forming a polarizing film exhibits a nematic liquid crystal phase or a smectic liquid crystal phase can be confirmed, for example, as follows. After preparing a suitable substrate and applying a composition for forming a polarizing film to the substrate to form a coating film, the solvent contained in the coating film is removed by subjecting the polymerizable liquid crystal compound to heat treatment or reduced pressure treatment under conditions that do not polymerize. Subsequently, the coating film formed on the substrate is heated to an isotropic temperature, and the liquid crystal phase expressed by cooling slowly is inspected by texture observation with a polarizing microscope, X-ray diffraction measurement, or differential scanning calorimetry. In this inspection, for example, a polymerizable liquid crystal compound that exhibits a nematic liquid crystal phase by cooling and a smectic liquid crystal phase by further cooling is particularly preferable. In the nematic liquid crystal phase and the smectic liquid crystal phase, the fact that the polymerizable liquid crystal compound and the dichroic dye are not phase separated can be confirmed by, for example, surface observation using various microscopes or scattering degree measurement using a haze meter.

Hereinafter, the specific example of what is preferable as a polymerizable liquid crystal compound used for the composition for polarizing film formation is given.

As a preferable polymerizable liquid crystal composition, a compound represented by Formula (4) (hereinafter, sometimes referred to as “compound (4)”) is exemplified.

U^One-V^One-W^One-X^One-Y^One-X²-Y²-X³-W²-V²-U² (4)

[In the formula (4), X ¹ , X ² and X ³ each independently represent a 1,4-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 1,4-phenylene group which may have a substituent. -CH ₂ -constituting a cyclohexane-1,4-diyl group which may have a substituent may be substituted with -O-, -S- or -NR-. R is a C1-C6 alkyl group or a phenyl group.

Y ¹ and Y ² are independently of each other -CH ₂ CH ₂ -, -CH ₂ O-, -COO-, -OCOO-, single bond, -N=N-, -CR ^a =CR ^b -, -C≡ C- or -CR ^a =N-. R ^a and R ^b independently of each other 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 independently of each other represent a single bond, -O-, -S-, -COO- or -OCOO-.

V ¹ and V ² represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent independently of each other, and -CH ₂ -constituting the alkanediyl group is substituted with -O-, -S- or -NH- It may be done.]

In compound (4), it is preferable that at least two of X ¹ , X ² and X ³ are 1,4-phenylene groups which may have a substituent.

It is preferable that the 1,4-phenylene group which may have a substituent is unsubstituted. The cyclohexane-1,4-diyl group which may have a substituent is preferably a trans-cyclohexane-1,4-diyl group which may have a substituent, and a trans-cyclohexane-1,4- which may have a substituent. The diyl group is more preferably unsubstituted.

As the substituent optionally having a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent, alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group and butyl group; Cyano group; And halogen atoms.

Y ¹ of compound (4) 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. U ¹ and U ² are preferably a polymerizable group together, and more preferably a photopolymerizable group together. The photopolymerizable group refers to a group capable of participating in the polymerization reaction by an active radical or acid generated from a photopolymerization initiator described later. The polymerizable liquid crystal compound having a photopolymerizable group is advantageous in that it can polymerize under lower temperature conditions.

In the compound (4), the polymerizable groups of U ¹ and U ² may be different from each other, but are preferably the same kind of group. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Especially, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

Examples of the alkanediyl group having 1 to 20 carbon atoms which may have the substituents represented by V ¹ and V ² include a methylene group, ethylene group, propane-1,3-diyl group, butane-1 ,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group , A decane-1,10-diyl group, a tetradecane-1,14-diyl group, and an aicosan-1,20-diyl group. V ¹ and V ² are preferably an alkanediyl group having ² to 12 carbon atoms, and more preferably an alkanediyl group having 6 to 12 carbon atoms.

Examples of the substituent optionally having an alkanediyl group having 1 to 20 carbon atoms which may have a substituent include a cyano group and a halogen atom. The alkanediyl group is preferably unsubstituted, and unsubstituted and straight-chain alkanediyl group. It is more preferable.

W ¹ and W ² are each independently a single bond or -O-.

Examples of the compound (4) include compounds represented by formulas (4-1) to (4-43). When the specific example of such compound (4) has a cyclohexane-1,4-diyl group, it is preferable that such cyclohexane-1,4-diyl group is a transchain.

The polymerizable liquid crystal compound may be used alone or in combination of two or more in a composition for forming a polarizing film. Moreover, when mixing 2 or more types, it is preferable if at least 1 type is a compound (4). The mixing ratio when two types of polymerizable liquid crystal compounds are mixed is usually 1:99 to 50:50, preferably 5:95 to 50:50, and more preferably 10:90 to 50:50.

Among the illustrated compound (4), formula (4-5), formula (4-6), formula (4-7), formula (4-8), formula (4-9), formula (4-10), formula (4-11), Expression (4-12), Expression (4-13), Expression (4-14), Expression (4-15), Expression (4-22), Expression (4-24), Expression ( Compounds represented by 4-25), formulas (4-26), formulas (4-27), formulas (4-28), and formulas (4-29) are preferred. These compounds can be easily polymerized under interaction with other polymerizable liquid crystal compounds under temperature conditions below the crystalline phase transition temperature, i.e., while maintaining the liquid state of the higher order smectic phase sufficiently. Specifically, these compounds can be polymerized under a temperature condition of 70°C or lower, preferably 60°C or lower, while sufficiently maintaining a high-order smectic liquid crystal state.

The content ratio of the polymerizable liquid crystal compound in the composition for forming a polarizing film is preferably 50 to 99.9% by mass, more preferably 80 to 99.9% by mass with respect to the solid content of the composition for forming a polarizing film. When the content ratio of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to increase, which is preferable. Here, solid content means the total amount of the components except for volatile components, such as a solvent, in the composition for polarizing film formation.

The polymerizable liquid crystal compound is, for example, Lub et al. Recl. Trav. Chim. It is prepared by a known method described in Pays-Bas, 115, 321-328 (1996) or Japanese Patent No. 4719156.

1-3. solvent

It is preferable that the composition for polarizing film formation contains a solvent. As the solvent, a solvent capable of completely dissolving the polymerizable liquid crystal compound and the dichroic dye is preferable. Moreover, it is preferable that it is a solvent inert to the polymerization reaction of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film.

Examples of the solvent 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; Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone or 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; Aromatic hydrocarbon solvents such as toluene and xylene; Nitrile solvents such as acetonitrile; Ether solvents such as tetrahydrofuran and dimethoxyethane; And chlorine-containing solvents such as chloroform and chlorobenzene. These solvents may be used alone or in combination of a plurality.

The content of the solvent is preferably 50 to 98% by mass relative to the total amount of the composition for forming the polarizing film. In other words, 2-50 mass% of solid content in the composition for polarizing film formation is preferable. When the solid content is 2% by mass or more, it is preferable because there is a tendency to easily obtain a thin polarized polarizing film which is one of the objects of the present invention. Moreover, since the viscosity of the composition for polarizing film formation becomes low when the said solid content is 50 mass% or less, since the thickness of a polarizing film becomes substantially uniform, the polarizing film tends to become difficult to generate|occur|produce, and it is preferable. In addition, such a solid content can be determined in consideration of the thickness of the polarizing film.

1-4. Other additives

The composition for forming a polarizing film in the present invention optionally contains additives other than a dichroic dye, a polymerizable liquid crystal compound, and a solvent.

1-4-1. Polymerization reaction aid

It is preferable that the composition for forming a polarizing film contains a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction of the polymerizable liquid crystal compound. As the polymerization initiator, a photopolymerization initiator is preferable in that a polymerization reaction can be started under low temperature conditions. Specifically, a compound that generates active radicals or acids by the action of light is used as a photopolymerization initiator. Among the photopolymerization initiators, it is more preferable to generate active radicals by the action of light.

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

Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

Examples of benzophenone compounds include benzophenone, o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3',4,4'-tetra(tert-butylperoxycar Carbonyl) benzophenone and 2,4,6-trimethylbenzophenone.

Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morph Polynophenyl)butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethan-1-one, 2-hydroxy Hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexylphenylketone and 2-hydroxy-2-methyl-1-[4- (1-methylvinyl)phenyl] propan-1-one oligomer and the like.

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

As the triazine compound, for example, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4 -Methoxynaphthyl)-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) Tenyl]-1,3,5-triazine and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine, etc. Can be mentioned.

A commercially available initiator can also be used. As commercially available polymerization initiators, "Irgacure 907", "Irgacure 184", "Irgacure 651", "Irgacure 819", "Irgacure 250", "Irgacure 369" ( Chiba Japan Co., Ltd.); "Seikool BZ", "Seikool Z", "Seikool BEE" (Seiko Chemical Co., Ltd.); "Kayacure BP100" (Nippon Kayaku Co., Ltd.); "Kayacure UVI-6992" (manufactured by Dow Corporation); "Adeka Optoma SP-152", "Adeka Optoma SP-170" (ADEKA); "TAZ-A", "TAZ-PP" (Nihon Siberheg Screw); And "TAZ-104" (Sanwa Chemical Co., Ltd.).

When the composition for forming a polarizing film contains a polymerization initiator, the content thereof can be appropriately adjusted depending on the type and amount of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film, usually 100 mass in total of the polymerizable liquid crystal compound The content of the polymerization initiator with respect to parts is 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass. When the content of the polymerization initiator is within the above range, it is preferable because it is possible to polymerize the orientation of the polymerizable liquid crystal compound without disturbing it.

1-4-2. Photosensitizer

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

When the composition for forming a polarizing film contains a photopolymerization initiator and a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film is further promoted. The content of the photosensitizer can be appropriately adjusted depending on the type and amount of the photopolymerization initiator and the polymerizable liquid crystal compound used in combination, and is usually 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound, preferably Is 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass.

1-4-3. Polymerization inhibitor

The composition for forming a polarizing film may contain a polymerization inhibitor to stably advance the polymerization reaction of the polymerizable liquid crystal compound. The degree of progress of the polymerization reaction of the polymerizable liquid crystal compound can be controlled by the polymerization inhibitor.

Examples of the polymerization inhibitor include radicals such as hydroquinone, alkoxy group-containing hydroquinone, alkoxy group-containing catechol (for example, butyl catechol, etc.), pyrogallol, 2,2,6,6-tetramethyl-1-piperidinyloxy radical. Supplements; Thiophenols; and β-naphthylamines and β-naphthols.

When a polymerization inhibitor is included in the composition for forming a polarizing film, the content is appropriately adjusted depending on the type and amount of the polymerizable liquid crystal compound used, and the content of the photosensitizer, and is usually based on 100 parts by mass of the polymerizable liquid crystal compound. It is 0.1-30 mass parts, Preferably it is 0.5-10 mass parts, More preferably, it is 0.5-8 mass parts.

When the content of the polymerization inhibitor is within the above range, it is preferable because the orientation of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film can be polymerized without disturbing the orientation.

1-4-4. Leveling agent

It is preferable that the composition for forming a polarizing film contains a leveling agent. The leveling agent has a function of adjusting the fluidity of the composition for forming a polarizing film to make the coating film obtained by applying the composition for forming a polarizing film more flat, and a surfactant and the like. Preferred leveling agents include leveling agents based on a polyacrylate compound, leveling agents based on a fluorine atom-containing compound, and the like.

Leveling agents based on polyacrylate compounds include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK-358N", and "BYK- 361N", "BYK-380", "BYK-381" and "BYK-392" (BYK Chemie).

Examples of leveling agents based on fluorine atom-containing compounds are "megapark R-08", copper "R-30", copper "R-90", copper "F-410", copper "F-411", and copper "F" -443", East "F-445", East "F-470", East "F-471", East "F-477", East "F-479", East "F-482" and East "F- 483" [DIC Corporation]; "Suplon S-381", copper "S-382", copper "S-383", copper "S-393", copper "SC-101", copper "SC-105", "KH-40" and " SA-100" [AGC Chemical Co., Ltd.]; "E1830", "E5844" (Daikin Fine Chemical Genkyusho); "F-top EF301", copper "EF303", copper "EF351", copper "EF352" (Mitsubishima terri alden Shigasei Co., Ltd.) etc. are mentioned.

When a leveling agent is contained in the composition for forming a polarizing film, the content is usually 0.3 parts by mass or more and 5 parts by mass or less, preferably 0.5 parts by mass or more and 3 parts by mass or less, based on 100 parts by mass of the content of the polymerizable liquid crystal compound. . When the content of the leveling agent is within the above-mentioned range, it is easy to align the polymerizable liquid crystal compound horizontally, and it is preferable because the polarizing film obtained tends to be smoother. When the content of the leveling agent in the polymerizable liquid crystal compound exceeds the above-mentioned range, the resulting polarizing film tends to be easily stained. Meanwhile, the polarizing film forming composition may contain two or more kinds of leveling agents.

2. Formation method of the present polarizing film

Next, a method of forming the present polarizing film with the composition for forming a polarizing film will be described. In such a method, the present polarizing film is formed by applying the composition for forming a polarizing film to a substrate, preferably a transparent substrate.

2-1. Transparent substrate

A transparent substrate is a substrate having transparency sufficient to transmit light, particularly visible light. The transparency refers to a property in which transmittance to light rays over a wavelength of 380 to 780 nm is 80% or more. Specifically, examples of the transparent substrate include a glass substrate and a plastic substrate, and are preferably plastic substrates. Examples of the plastic constituting the plastic substrate include polyolefins such as polyethylene, polypropylene, and norbornene polymers; Cyclic olefin resins; Polyvinyl alcohol; Polyethylene terephthalate; Polymethacrylic acid esters; Polyacrylic acid esters; Cellulose esters such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate; Polyethylene naphthalate; Polycarbonate; Polysulfone; Polyethersulfone; Polyether ketone; And plastics such as polyphenylene sulfide and polyphenylene oxide. Among them, cellulose esters, cyclic olefin resins, polyethylene terephthalate or polymethacrylic acid esters are particularly preferred because they are readily available on the market or have excellent transparency. In manufacturing the present polarizing film using such a transparent substrate, a support substrate or the like is adhered to the transparent substrate in that it can be easily handled without causing damage such as tearing when transporting or storing the transparent substrate. You may put it. Moreover, although it mentions later, when manufacturing a circular polarizing plate with this polarizing film, there may be a case where a phase difference property is provided to a plastic base material. In this case, the retardation property may be given to the plastic substrate by stretching treatment or the like.

When giving a retardation property to a plastic base material, a plastic base material which consists of a cellulose ester or a cyclic olefin resin is preferable at the point that it is easy to control the retardation value.

In the cellulose ester, at least a part of hydroxyl groups contained in cellulose is acetic acid esterified. The cellulose ester film made of such a cellulose ester can be easily obtained in the market. As a commercially available triacetyl cellulose film, for example, "Fuji Tak Film" (Fuji Shashin Film Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (Konica Minolta Opt.). Such a commercially available triacetylcellulose film can be used as a transparent base material as it is or after providing retardation properties as necessary. In addition, it can be used as a transparent substrate after surface treatment such as anti-glare treatment, hard coat treatment, antistatic treatment or antireflection treatment is performed on the surface of the prepared transparent substrate.

In order to provide retardation property to a plastic substrate, it is by a method such as stretching the plastic substrate as described above. Any plastic base material made of a thermoplastic resin can be stretched, but a plastic base material made of a cyclic olefin resin is more preferable because it is easy to control the retardation property. The cyclic olefin-based resin is composed of, for example, a polymer or copolymer of a cyclic olefin such as norbornene or polycyclic norbornene-based monomer, and the cyclic olefin-based resin may partially include a ring-opening part. Moreover, you may hydrogenated the cyclic olefin resin containing a ring-opening part. Further, the cyclic olefin-based resin may be a copolymer of, for example, a cyclic olefin with a chain olefin or a vinylated aromatic compound (styrene, etc.), in that it does not significantly impair transparency or significantly increase hygroscopicity. In addition, a polar group may be introduced into the cyclic olefin-based resin.

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 or propylene, and examples of the vinylated aromatic compound are 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%, based on the total structural unit of the cyclic olefin resin. When the cyclic olefin resin is a ternary copolymer 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 about 5 to 80 mol% based on the total structural unit of the cyclic olefin resin. And the content ratio of the structural unit derived from the vinylated aromatic compound is about 5 to 80 mol%. The cyclic olefin-based resin of such a terpolymer has an advantage in that the amount of the expensive cyclic olefin can be relatively reduced when producing the cyclic olefin-based resin.

Cyclic olefin resins are readily available on the market. As a commercially available cyclic olefin resin, "Topas" [Ticona (Germany)]; "Aton" [JSR Corporation]; "ZEONOR" and "ZEONEX" (Nippon Xeon Corporation); And "Apel" (manufactured by Mitsui Chemical Co., Ltd.). Such a cyclic olefin-based resin can be formed into a film (cyclic olefin-based resin film) by forming a film by a known film forming means such as a solvent casting method or a melt extrusion method. Moreover, the cyclic olefin resin film already marketed in the form of a film can also be used. As such a commercially available cyclic olefin resin film, "Essina" and "SCA40" (Sekisui Chemical Co., Ltd.); "Zeono Film" [Optes Co., Ltd.]; "Aton Film" [JSR Co., Ltd.] etc. are mentioned.

Next, a method of imparting retardation property to the plastic substrate will be described. The plastic substrate can impart retardation properties by a known stretching method. For example, a roll (winding body) in which a plastic base material is wound on a roll is prepared, and the plastic base material is continuously released from the winding body, and the released plastic base material is conveyed to a heating furnace. The set temperature of the heating furnace is in the range of the glass transition temperature of the plastic substrate (°C) to [glass transition temperature +100] (°C), preferably near the glass transition temperature (°C) to [glass transition temperature +50] (°C) ). In the above-described heating furnace, when stretching in the traveling direction of the plastic substrate or in a direction orthogonal to the traveling direction, the transport direction or tension is adjusted to give an inclination at an arbitrary angle to perform uniaxial or biaxial thermal stretching treatment. The draw ratio is usually in the range of about 1.1 to 6 times, and preferably in the range of about 1.1 to 3.5 times. Moreover, as a method of extending in an oblique direction, if the orientation axis can be continuously inclined at a desired angle, it is not particularly limited and a known stretching method can be adopted. As such a stretching method, the method described in Unexamined-Japanese-Patent No. 50-83482 or Unexamined-Japanese-Patent No. 2-113920 is mentioned, for example.

The thickness of the transparent base material is preferably thin in terms of being able to secure sufficient transparency and sufficient weight for practical handling, but if it is too thin, the strength tends to decrease and workability tends to be poor. The suitable thickness of the glass substrate is, for example, about 100 to 3000 μm, and preferably about 100 to 1000 μm. A suitable thickness of the plastic substrate is, for example, about 5 to 300 µm, and preferably about 20 to 200 µm. When this polarizing film is used as a circular polarizing plate to be described later, the thickness of the transparent substrate is particularly preferably about 20 to 100 µm when used as a circular polarizing plate for mobile devices. On the other hand, in the case of providing retardation to the film by stretching, the thickness after stretching is determined by the thickness before stretching or the stretching ratio.

2-2. Alignment film

It is preferable that an alignment film is formed in the base material used for manufacture of this polarizing film. In that case, the composition for forming a polarizing film is applied on the alignment film. For this reason, it is preferable that the said alignment film has solvent tolerance to the extent that it does not melt|dissolve by application|coating of the composition for polarizing film formation, etc. Moreover, it is preferable to have heat resistance in the heat treatment for removal of a solvent and orientation of a liquid crystal. Such an alignment film can be formed of an alignment polymer.

Examples of the oriented polymer include polyamide or gelatin having an amide bond in a molecule, polyimide having an imide bond in a molecule, and polyamic acid, a hydrolyzate thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxa And polymers such as sol, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid or polyacrylic acid esters. Among these, polyvinyl alcohol is preferable. These oriented 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 coating on the substrate as an alignment polymer composition (solution containing an alignment polymer) dissolved in a solvent. Examples of the solvent include 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; Ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone and methyl isobutyl ketone; Aliphatic hydrocarbon solvents such as pentane, hexane and heptane; Aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile; Ether solvents such as tetrahydrofuran and dimethoxyethane; And chlorine-substituted hydrocarbon solvents such as chloroform and chlorobenzene. These organic solvents may be used alone or in combination of a plurality of species.

Further, a commercially available alignment film material may be used as it is as an alignment polymer composition for forming an alignment film. Examples of commercially available alignment film materials include San-Eva (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) or Optoma (registered trademark, manufactured by JSR Corporation), and the like.

As a method of forming an alignment film on a substrate, for example, a method of annealing by applying the above-mentioned oriented polymer composition or a commercially available alignment film material onto the substrate may be mentioned. The thickness of the alignment film thus obtained is usually in the range of 10 nm to 10000 nm, preferably in the range of 10 nm to 1000 nm.

It is preferable to perform rubbing (rubbing method) as necessary in order to impart an orientation regulating force to the alignment film. The polymerizable liquid crystal compound can be oriented in a desired direction by applying an alignment regulating force.

As a method of imparting an orientation regulating force by the rubbing method, for example, a rubbing cloth is rolled up, a rotating rubbing roll is prepared, and a laminate having a coating film for forming an alignment film formed on a substrate is placed on a stage, and toward a rotating rubbing roll. By conveying, the method of contacting the said coating film for orientation film formation and a rotating rubbing roll is mentioned.

Further, a so-called photo-alignment film can also be used. With the photo-alignment film, a composition comprising a polymer or monomer having a photoreactive group and a solvent (hereinafter referred to as “a composition for forming a photo-alignment layer” in some cases) is applied to a substrate to irradiate polarized light (preferably polarized UV). By doing so, it refers to an alignment film to which an orientation regulating force is applied. The photoreactive group refers to a group that generates liquid crystal alignment ability by irradiating light (light irradiation). Specifically, it causes the photoreaction which is the origin of the liquid crystal alignment ability, such as an alignment organic or isomerization reaction, a dimerization reaction, a photocrosslinking reaction, or a photolysis reaction of molecules generated by irradiation of light. It is preferable to produce a dimerization reaction or a photocrosslinking reaction among the photoreactive groups in that it has excellent orientation and maintains a smectic liquid crystal state when a polarizing film is formed. As the photoreactive group capable of causing the above reaction, it is preferable to have an unsaturated bond, particularly a double bond, and a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), nitrogen Particularly preferred is a group having at least one selected from the group consisting of a nitrogen double bond (N=N bond) and a carbon-oxygen double bond (C=O bond).

Examples of the photoreactive group having a C=C bond include a vinyl group, a polyene group, a steelbene group, a steelbazole group, a steelbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C=N bond include a group having a structure such as an aromatic sheep 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 bis azo group, and a formazan group, and those having azoxybenzene as a basic structure. 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 substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups and halogenated alkyl groups.

Among them, a photoreactive group capable of inducing a photodimerization reaction is preferable, and since cinnamoyl group and chalcone group require relatively little polarization irradiation amount for photo-alignment, and it is easy to obtain a photo-alignment film excellent in thermal stability or stability over time. Do. More specifically, it is particularly preferable that the polymer having a photoreactive group has a cinnamoyl group in which the terminal end of the polymer side chain has a cinnamic acid structure.

As a solvent of the composition for forming a photo-alignment layer, it is preferable to dissolve a polymer and a monomer having a photoreactive group, and examples of the solvent include a solvent used in the above-mentioned oriented polymer composition.

The concentration of the polymer or monomer having a photoreactive group with respect to the composition for forming a photo-alignment layer can be appropriately adjusted according to the type of the polymer or monomer having the photoreactive group or the thickness of the photo-alignment film to be produced. It is preferable to use 0.2 mass%, and the range of 0.3 to 10 mass% is particularly preferable. In addition, in a range in which the properties of the photo-alignment film are not significantly impaired, the composition for forming the alignment layer may contain a polymer material such as polyvinyl alcohol or polyimide, and a photosensitizer.

As a method of applying the oriented polymer composition or the composition for forming a photo-alignment layer onto a substrate, spin coating, extrusion, gravure coating, die coating, bar coating, and applicator coating methods, flexo methods, etc. A known method such as a printing method is employed. On the other hand, when the production of the polarizing film is performed by a continuous manufacturing method of a RolltoRoll type described later, a printing method such as a gravure coating method, a die coating method, or a flexo method is usually employed.

On the other hand, if masking is performed during rubbing or polarization irradiation, a plurality of regions (patterns) with different orientation directions may be formed.

2-3. Manufacturing method of the present polarizing film

A composition for forming a polarizing film is coated on the substrate or the alignment film formed on the substrate to obtain a coating film. As a method of coating the composition for forming a polarizing film, for example, the same method as exemplified as a method of applying a composition for forming an oriented polymer or a photoreactive layer to a substrate can be mentioned.

Subsequently, a dry film is formed by drying and removing the solvent under the condition that the polymerizable 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 heating drying method and a vacuum drying method.

Subsequently, as a preferred form, once the liquid crystal state of the polymerizable liquid crystal composition contained in the dry film is a nematic liquid crystal phase, the nematic liquid crystal phase is transferred to a smectic liquid crystal phase.

In order to form a smectic liquid crystal phase via the nematic liquid crystal phase in this way, for example, the polymerizable liquid crystal compound contained in the dry film is heated to a temperature or higher representing the nematic liquid crystal phase, and then the polymerizable liquid crystal compound is smectic. A method of cooling to a temperature representing a liquid crystal phase is adopted.

When the polymerizable liquid crystal compound in the dry film is a smectic liquid crystal phase or the polymerizable liquid crystal compound is a smectic liquid crystal phase via a nematic liquid crystal phase, by measuring the phase transition temperature of the polymerizable liquid crystal compound used , It is possible to obtain a condition (heating condition) for controlling the liquid crystal state. The conditions for measuring the phase transition temperature are described in the Examples herein.

Next, the polymerization step of the polymerizable liquid crystal compound will be described. Here, the photopolymerization initiator is contained in the composition for forming a polarizing film, the liquid crystal state of the polymerizable liquid crystal compound in the dry film is a smectic liquid crystal phase, and then the liquid crystal state of the smectic liquid crystal phase is maintained while the polymerizable liquid crystal compound is The method for photopolymerizing is described in detail.

In the photopolymerization, the light to be irradiated on the dry film is appropriate depending on the type of photopolymerization initiator or the type of the polymerizable liquid crystal compound (especially, the type of the polymerizable group of the polymerizable liquid crystal compound) and the amount thereof. It can be performed by light or active electron beam selected from the group consisting of visible light, ultraviolet light and laser light. Of these, ultraviolet light is preferred in that it is easy to control the progress of the polymerization reaction and that a device widely used in the art can be used as a device for photopolymerization. Therefore, it is preferable to select the type of the polymerizable liquid crystal compound or photopolymerization initiator contained in the composition for forming a polarizing film so that photopolymerization can be performed by ultraviolet light. Moreover, when superposing|polymerizing, the polymerization temperature can also be controlled by cooling a dry film by suitable cooling means together with ultraviolet light irradiation. By employing such a cooling means, if polymerization of the polymerizable liquid crystal compound can be performed at a lower temperature, even if a relatively low heat resistance is used for the above-described substrate, there is also an advantage that the present polarizing film can be suitably formed. On the other hand, it is also possible to obtain the present polarizing film patterned by masking or developing during photopolymerization.

By performing the photopolymerization as described above, the polymerizable liquid crystal compound is polymerized while maintaining a nematic liquid crystal phase, a smectic liquid crystal phase, and preferably a higher order smectic liquid crystal phase as already exemplified to form the polarizing film. This polarizing film obtained by polymerizing a polymerizable liquid crystal compound while maintaining a smectic liquid crystal phase is a conventional host guest type polarizing film, that is, a polarizing film obtained by polymerizing a polymerizable liquid crystal compound or the like while maintaining the liquid crystal state of a nematic liquid crystal phase Compared with the above, there is an advantage that the polarization performance is high. In addition, there is an advantage that the strength is excellent compared to the application of only the lyotropic dichroic dye.

The thickness of the polarizing film thus formed is preferably 0.5 µm or more and 10 µm or less, more preferably 1 µm or more and 5 µm or less. Therefore, the thickness of the coating film for forming the polarizing film is determined in consideration of the thickness of the obtained polarizing film. On the other hand, the thickness of the polarizing film is determined by measurement of an interference film thickness meter, a laser microscope, or a tactile film thickness meter.

The polarizing film thus formed is particularly preferable as long as the Bragg peak is obtained in the X-ray diffraction measurement as described above. As this main polarizing film in which such a Bragg peak is obtained, the main polarizing film which shows a diffraction peak originating in a hexatic phase or a crystal phase is mentioned, for example.

In addition, the polarizing film produced in this way is excellent in neutral color properties. Here, with the polarizing film excellent in neutral color property, the color coordinates a* and b* values in the L*a*b*(Lab) colorimeter satisfy the relationship of the following equations (1F) and (2F). Is to do. On the other hand, these color coordinates a* value and b* value are obtained, for example, by the measurement method described in the examples herein.

-3≤ Chromaticity a*≤3 (1F)

-3≤ Chromaticity b*≤3 (2F)

The color coordinates a* and b* values referred to herein are also referred to as "chromaticity a*" and "chromaticity b*". The a* and b* together are judged to be polarizing films having a neutral color as they are closer to 0 (zero). In a display device equipped with such a polarizing film, a good white display without coloring can be obtained.

In addition, in the color of the polarizing film, when the two polarizing films were superimposed so that the absorption axes were orthogonal to each other, the color at that time was obtained in the same manner as described above, and when "orthogonal a*" and "orthogonal b*" were calculated, such orthogonality It is more preferable if each of a* and orthogonal b* satisfies the relationship of the following formulas (1F') and (2F'). These orthogonal a* and orthogonal b* are indicative of whether the color of the black display is neutral in a display device equipped with a polarizing film. When the orthogonal a* and the orthogonal b* are closer to 0 (zero) together, a better black display without coloring can be obtained.

-3≤Orthogonal a*≤3 (1F')

-3≤Orthogonal b*≤3 (2F')

3. Continuous manufacturing method of this polarizing film

In the above, although the outline 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 a RolltoRoll type, and is sometimes referred to as a "main manufacturing method" in some cases. In addition, in this manufacturing method, it demonstrates centering around the case where a base material is a transparent base material. When the base material is a transparent base material, what is finally obtained is a polarizer having a transparent base material and a main polarizing film (hereinafter, referred to as "main polarizer" in some cases).

The manufacturing method is, for example,

A step of preparing a first roll in which a transparent substrate is wound around a first winding,

The step of continuously transmitting the transparent substrate from the first roll,

A process of continuously forming an alignment film on the transparent substrate,

A step of continuously applying a composition for forming a polarizing film on the alignment layer,

A step of continuously forming a dry film on the alignment film by drying the applied polarizing film forming composition under conditions in which the polymerizable liquid crystal compound is not polymerized,

After making the polymerizable liquid crystal compound contained in the dry film into a nematic liquid crystal phase, preferably a smectic liquid crystal phase, and then maintaining the smectic liquid crystal phase, polymerizing the polymerizable liquid crystal compound, the polarizing film is continuously The process to obtain a polarizer,

It has the process of winding a polarizer obtained continuously in a 2nd winding core, and obtaining a 2nd roll. Here, with reference to FIG. 1, the manufacturing method of this manufacturing method is demonstrated especially regarding the case where an optical alignment film is used as an alignment film.

The first roll 210 on which the transparent substrate is wound around the first winding core 210A is readily available, for example, from the market. Examples of the transparent substrate that can be obtained in the market in the form of such a roll include films made of cellulose ester, cyclic olefin resin, polyethylene terephthalate, polycarbonate or polymethacrylic acid ester among the transparent substrates already exemplified. Moreover, when using this polarizing film as a circular polarizing plate, the transparent base material previously provided with the phase difference property can also be obtained easily from a market, For example, a phase difference film etc. which consist of a cellulose ester or a cyclic olefin resin.

Subsequently, the transparent substrate is released from the first roll 210. The method of releasing the transparent substrate is performed by providing suitable rotating means on the winding core 210A of the first roll 210 and rotating the first roll 210 by the rotating means. Further, an auxiliary roll 300 suitable for a direction in which the transparent substrate is conveyed from the first roll 210 is provided, and the transparent substrate can be released by means of rotating the auxiliary roll 300. In addition, both of the first winding core 210A and the auxiliary roll 300 may be provided with a rotating means to release the transparent substrate while providing appropriate tension to the transparent substrate.

When the transparent substrate released from the first roll 210 passes through the coating device 211A, a composition for forming a photo-alignment layer is coated on the surface by the coating device 211A. In order to continuously apply the composition for forming the photo-alignment layer as described above, printing methods such as a gravure coating method, a die coating method, and a flexo method are performed by the coating device 211A.

The transparent base material which has passed through the coating device 211A is conveyed to the drying furnace 212A, and heated by the drying furnace 212A to continuously form a first dry film on the transparent substrate. As the drying furnace 212A, for example, a hot air type drying furnace or the like is used. The set temperature of the drying furnace 212A is determined according to the kind of solvent contained in the composition for forming the photo-alignment layer applied by the coating device 211A. Further, the drying furnace 212A may be divided into a plurality of zones, and may have a format in which a set temperature is different for each of the divided zones, or a plurality of drying furnaces may be arranged in series to form a drying furnace having a different set temperature for each drying furnace.

The first dry film continuously formed by passing through the heating furnace 212A is then irradiated with polarized UV to the surface of the first dry film side or the surface of the transparent substrate by the polarized UV irradiation device 213A, and the first dry film The film forms an (optical) alignment film. At this time, the angle formed by the transport direction D1 of the transparent substrate and the alignment direction D2 of the photo-alignment film formed may intersect. Fig. 2 is a schematic view showing the relationship between the alignment direction D2 of the photo-alignment film formed after polarized UV irradiation and the transport direction D1 of the transparent substrate. That is, FIG. 2 shows that when the surface of the first stacked body after passing through the polarized UV irradiation device 213A is seen when the transport direction D1 of the transparent substrate and the alignment direction D2 of the photo-alignment film are formed, the angles formed by them represent approximately 45°. have.

In this way, the transparent substrate (first layered product) on which the photo-alignment film is continuously formed is then passed through the coating device 211B, and then the composition for forming the polarizing film is coated on the photo-alignment film, and then passes through the drying furnace 212B. By passing through the drying furnace 212B, the polymerizable liquid crystal compound contained in the polarizing film forming composition forms a nematic liquid crystal phase, preferably a smectic liquid crystal phase, and a second dry film is formed.

The transparent substrate that has passed through the drying furnace 212B has sufficiently removed the solvent contained in the composition for forming a polarizing film, so that the polymerizable liquid crystal compound in the second dry film is a nematic liquid crystal phase, preferably a liquid crystal state of the smectic liquid crystal phase. It is conveyed to the light irradiation device 213B while holding. By light irradiation by the light irradiation device 213B, the polymerizable liquid crystal compound is photopolymerized while maintaining the liquid crystal state, and the polarizing film is continuously formed on the alignment film to obtain the polarizer.

The polarizing film continuously formed in this way is wound on the second winding core 220A in the form of a laminate including a transparent substrate and an alignment film, so that the form of the second roll 220 is obtained. When the formed second polarizing film is wound to obtain a second roll, co-winding using a suitable spacer may be performed.

Thus, the transparent base material is in the order of the first roll/applying device 211A/drying furnace 212A/polarizing UV irradiating device 213A/applying device 211B/drying furnace 212B/lighting irradiating device 213B By passing through, the polarizing film seen on the photo-alignment film on the transparent substrate is continuously formed to produce the polarizer.

In addition, in the present manufacturing method shown in FIG. 1, a method of continuously manufacturing the transparent substrate to the polarizing film as seen has been shown, but, for example, the transparent substrate is first roll/application device 211A/drying furnace 212A/polarization The first stacked body continuously formed by winding in the order of the UV irradiation device 213A is wound around the core, the first stacked body is manufactured in the form of a roll, and the first stacked body is unwound and released from the roll. The polarizer may be manufactured by passing the first laminate in the order of the coating device 211B/drying furnace 212B/light irradiation device 213B.

The polarizer obtained by the present production method has a film shape and an elongated shape. When this polarizing film is used for a liquid crystal display device or the like described later, it is cut and used to have a desired dimension in accordance with the scale of the liquid crystal display device.

As described above, the configuration and manufacturing method of the polarizer seen mainly in the case of a laminate of the transparent substrate/light-alignment film/this polarizing film has been described, but the polarizing film can be obtained as a single layer by peeling the photo-alignment film or the transparent substrate from the polarizer. have. Moreover, you may make it the form which laminated|stacked the layer or film other than a transparent base material/light-alignment film/this polarizing film to this polarizer. As described above, as these layers and films, the polarizing film may further include a retardation film, or may further include an antireflection layer or a brightness enhancing film.

Further, by using the transparent substrate itself as a retardation film, a circular polarizing plate or an elliptical polarizing plate in the form of a retardation film/light alignment film/this polarizing film can also be used. For example, in the case of using a 1/4 wavelength plate uniaxially stretched as a retardation film, it is possible to produce a circular polarizing plate with RolltoRoll by setting the irradiation direction of polarized UV to be approximately 45° with respect to the conveying direction of the transparent substrate. It is preferable that the quarter wave plate used in manufacturing the circular polarizing plate has a characteristic that the in-plane retardation value for visible light becomes smaller as the wavelength becomes shorter.

In addition, using a 1/2 wave plate as a retardation film, a linear polarizing plate roll was set by shifting the angle between the slow axis and the absorption axis of the polarizing film, and a quarter wave plate was formed on the opposite side to the surface on which the polarizing film was formed. By further forming, it is also possible to form a circular circular polarizing plate.

4. Use of this polarizing film

This polarizing film can be used for various display devices. A display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. As the display device, for example, a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, an electron emission display device (for example, a field emission display device (FED), a surface field emission display device ( SED)), electronic paper (display device using electronic ink or electrophoretic elements, plasma display device, projection display device (such as a grating light valve (GLV) display device, a display device having a digital micromirror device (DMD))) and piezoelectric And ceramic displays, etc. The liquid crystal display device includes any of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, and a projection type liquid crystal display device. A display device displaying a two-dimensional image may be used, or a three-dimensional display device displaying a three-dimensional image may be used.

This polarizing film can be effectively used for a display device of an organic electroluminescence (EL) display device or an inorganic electroluminescence (EL) display device.

Fig. 3 is a schematic diagram showing a cross-sectional configuration of a liquid crystal display device (hereinafter referred to as "this liquid crystal display device" in some cases) using the present polarizing film. The liquid crystal layer 17 is sandwiched by two substrates 14a and 14b.

6 and 10 are schematic diagrams showing the cross-sectional configuration of an EL display device (hereinafter referred to as "the present EL display device" in some cases) using the present polarizing film.

11 is a schematic view showing the configuration of a projection type liquid crystal display device using the present polarizing film.

First, the liquid crystal display device 10 shown in Fig. 3 will be described.

A color filter 15 is disposed on the liquid crystal layer 17 side of the substrate 14a. The color filter 15 is disposed at a position facing the pixel electrode 22 with the liquid crystal layer 17 interposed therebetween, and the black matrix 20 is arranged at a position facing the boundary between the pixel electrodes. The transparent electrode 16 is disposed on the liquid crystal layer 17 side so as to cover the color filter 15 and the black matrix 20. On the other hand, an overcoat layer (not shown) may be provided between the color filter 15 and the transparent electrode 16.

The thin film transistor 21 and the pixel electrode 22 are regularly arranged on the liquid crystal layer 17 side of the substrate 14b. The pixel electrode 22 is disposed at a position facing the color filter 15 with the liquid crystal layer 17 interposed therebetween. An interlayer insulating film 18 having a connection hole (not shown) is disposed between the thin film transistor 21 and the pixel electrode 22.

Glass substrates and plastic substrates are used as the substrates 14a and 14b. As such a transparent substrate used for manufacturing the polarizing film, a glass substrate or a plastic substrate can be employed that is the same material as exemplified. Further, the transparent substrate 1 of the polarizing film may also serve as the substrate 14a and the substrate 14b. When a process of heating at a high temperature is required when manufacturing the color filter 15 or the thin film transistor 21 formed on the substrate, a glass substrate or a quartz substrate is preferable.

As the thin film transistor, an optimum one may be employed depending on the material of the substrate 14b. Examples of the thin film transistor 21 include a high temperature polysilicon transistor formed on a quartz substrate, a low temperature polysilicon transistor formed on a glass substrate, and an amorphous silicon transistor formed on a glass substrate or plastic substrate. In order to further downsize the liquid crystal display device, a driver IC may be formed on the substrate 14b.

A liquid crystal layer 17 is disposed between the transparent electrode 16 and the pixel electrode 22. Spacers 23 are disposed on the liquid crystal layer 17 in order to maintain a constant distance between the substrate 14a and the substrate 14b. On the other hand, although shown in FIG. 3 as a columnar spacer, the spacer is not limited to the columnar shape, and the shape is arbitrary as long as the distance between the substrate 14a and the substrate 14b can be kept constant.

Each member includes a substrate 14a, a color filter 15 and a black matrix 20, a transparent electrode 16, a liquid crystal layer 17, a pixel electrode 22, an interlayer insulating film 18 and a thin film transistor 21, And the substrates 14b.

Among the substrates 14a and 14b with the liquid crystal layer 17 interposed therebetween, polarizers 12a and 12b are provided on the outside of the substrate 14b, and a polarizer viewed from at least one of them is used. .

Moreover, it is preferable if retardation layers (for example, 1/4 wavelength plate or optical compensation film) 13a and 13b are laminated. Among the polarizers 12a and 12b, by disposing the polarizing film on the polarizer 12b, the function of converting incident light into linearly polarized light can be provided to the liquid crystal display device 10. On the other hand, the retardation films 13a and 13b may not be disposed depending on the structure of the liquid crystal display device or the type of liquid crystal compound contained in the liquid crystal layer 17, and the transparent substrate is a retardation film, and the original including the present polarizing film. In the case of using a polarizing plate, since the retardation film can be used as a retardation layer, the retardation layers 13a and/or 13b in FIG. 3 can be omitted. A polarizing film may be further provided on the light output side (outside) of the polarizer.

Further, an antireflection film for preventing reflection of external light may be disposed outside the main polarizer (when a polarizing film is further provided on the polarizing film).

As described above, the polarizer seen in the polarizer 12a or 12b of the liquid crystal display device 10 of FIG. 3 can be used. There is an effect that the thickness reduction of the present liquid crystal display device 10 can be achieved by providing the polarizers 12a and/or 12b.

When this polarizer is used for the polarizer 12a or 12b, the lamination order is not specifically limited. This will be described with reference to enlarged views of parts A and B surrounded by the dotted line in FIG. 3.

4 is an enlarged schematic cross-sectional view of part A of FIG. 3. 4(A1), when the present polarizer 100 is used as the polarizer 12a, the polarizing film 3, the photo-alignment film 2, and the transparent substrate 1 seen from the retardation layer 13a side are in the order described above. It shows that it is installed to be arranged. Moreover, FIG. 4(A2) shows that the transparent base material 1, the photo-alignment film 2, and the polarizing film 3 are provided in the above order from the phase difference layer 13a side.

5 is an enlarged schematic view of part B of FIG. 3. In (B1) of FIG. 5, when the present polarizer 100 is used as the polarizer 12b, the transparent substrate 1, the photo-alignment film 2, and the present polarizing film 3 are in this order from the retardation film 13b side. It is installed to be placed. In (B2) of FIG. 5, when the present polarizer 100 is used as the polarizer 12b, the polarizing film 3, the photo-alignment film 2, and the transparent substrate 1 viewed from the retardation film 13b side are in this order. It is installed to be placed.

A backlight unit 19, which is a light emitting source, is disposed outside the polarizer 12b. The backlight unit 19 includes a light source, a light guide, a reflector, a diffusion sheet, and a viewing angle adjustment sheet. Examples of light sources include electroluminescence, cold cathode tubes, hot cathode tubes, light emitting diodes (LEDs), laser light sources, and mercury lamps. In addition, the type of the polarizing film seen according to the characteristics of the light source can be selected.

When the liquid crystal display device 10 is a transmissive liquid crystal display device, the white light generated from the light source in the backlight unit 19 enters the light guide body, and the course is changed by the reflector to diffuse in the diffusion sheet. The diffused light enters the polarizer 12b from the backlight unit 19 after being adjusted to have a desired directivity by the viewing angle adjustment sheet.

Of the incident light which is unpolarized light, only one linearly polarized light passes through the polarizer 12b of the liquid crystal panel. The linearly polarized light is converted into circularly polarized light or elliptical polarized light by the retardation layer 13b, and sequentially passes through the substrate 14b, the pixel electrode 22, and the like to reach the liquid crystal layer 17.

Here, the presence or absence of a potential difference between the pixel electrode 22 and the opposing transparent electrode 16 changes the alignment state of the liquid crystal molecules included in the liquid crystal layer 17, and the light emitted from the liquid crystal display device 10 The luminance of is controlled. When the liquid crystal layer 17 is in an alignment state that converts and transmits polarized light, the polarized light passes through the liquid crystal layer 17 and the transparent electrode 16, and light in a specific wavelength range passes through the color filter 15. The polarizer 12a is reached, and the liquid crystal display device brightly displays the color determined by the color filter.

Conversely, when the liquid crystal layer 17 is in an alignment state that transmits polarized light as it is, the light transmitted through the liquid crystal layer 17, the transparent electrode 16, and the color filter 15 is absorbed by the polarizer 12a. Thereby, the pixel displays black. In the intermediate alignment state between these two states, since the luminance of light emitted from the liquid crystal display device 10 is also in the middle of both, the pixel displays an intermediate color.

When the present liquid crystal display device 10 is a semi-transmissive liquid crystal display device, it is preferable to use one in which a quarter wave plate is further laminated (circular polarizing plate) on the main polarizing film side of the polarizer. At this time, the pixel electrode 22 has a transmission portion formed of a transparent material and a reflection portion formed of a material that reflects light, and in the transmission portion, an image is displayed in the same manner as the transmission liquid crystal display described above. On the other hand, in the reflection unit, external light enters the liquid crystal display device, and the circularly polarized light transmitted through the polarizing film through the action of the 1/4 wavelength plate further provided in the polarizing film passes through the liquid crystal layer 17, and the pixel electrode ( It is reflected by 22) and used for display.

Next, this EL display device 30 using the present polarizing film will be described with reference to FIG. When using this polarizing film for this 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 circular polarizing plate. So, before explaining the configuration and the like of the EL display device 30, two embodiments of this circular polarizing plate will be described with reference to FIG.

7A is a schematic diagram showing a first embodiment of the circular polarizing plate 110. The first embodiment is the original polarizing plate 110 in which a retardation layer (phase difference film) 4 is further formed on the polarizing film 3 in the polarizer 100. 7B is a schematic diagram showing a second embodiment of the circular polarizing plate 110. In the second embodiment, the transparent base material 1 itself is used by using the transparent base material 1 (phase difference film 4) in which a retardation property is previously provided to the transparent base material 1 used when manufacturing the polarizer. It is the original polarizing plate 110 which has a function as the phase difference layer 4.

As the present circularly polarizing plate including the present polarizing film, the second embodiment of the above-mentioned circularly polarizing plate is preferable because the configuration is simple, and in this case, it is preferable to use a quarter wave plate as a transparent substrate, and furthermore, a transparent substrate. It is preferable if a quarter wave plate is used as and the requirements of (A1) and (A2) below are satisfied.

(A1) the angle between the absorption axis of the polarizing film and the slow axis of the quarter wave plate should be approximately 45°;

(A2) The value of the front retardation of the quarter wave plate measured at light having a wavelength of 550 nm should be in the range of 100 to 150 nm.

Here, the manufacturing method of this circular polarizing plate 110 is demonstrated. As already described in the second embodiment of the circular polarizing plate 110, in the present manufacturing method for manufacturing the present polarizing film 100, the transparent substrate 1, which is previously provided with retardation property as the transparent substrate 1, that is, the phase difference It can be manufactured by using a film. In the first embodiment of the circular polarizing plate 110, the retardation layer 4 may be formed by bonding a retardation film to the polarizing film 3 produced by the production method B. On the other hand, in the case of manufacturing the polarizing film 100 in the form of the second roll 220 by the present manufacturing method B, the polarizing film 100 seen from the second roll 220 is unwound, and predetermined dimensions are obtained. After being cut into, the circular polarizing plate having a film-like shape and an elongated shape may be prepared by preparing a third roll in which the retardation film is wound around the core, although it may be in the form of bonding the retardation film to the cut polarizing film 100. 110) may be continuously produced.

A method of continuously manufacturing the first embodiment of the circular polarizing plate 110 will be described with reference to FIG. 8. This manufacturing method,

A process of releasing the polarizer 100 viewed continuously from the second roll 220 and releasing the retardation film continuously from the third roll 230 on which the retardation film is wound,

A process of forming the original polarizing plate 110 by continuously bonding the polarizing film formed on the polarizer 100 released from the second roll 220 and the retardation film released from the third roll,

The formed circular polarizing plate 110 is wound on a fourth winding core 240A, and is made of a process of obtaining a fourth roll 240.

The manufacturing method of the first embodiment of the circular polarizing plate 110 has been described above. However, when bonding the retardation film with the polarizing film 3 in the polarizer 100, an appropriate pressure-sensitive adhesive is used to form the pressure-sensitive adhesive. The polarizing film 3 viewed through the adhesive layer and the retardation film may be bonded.

Next, this EL display device provided with the original polarizing plate 110 will be described again with reference to FIG. 6.

In the EL display device 30, an organic functional layer 36 and a cathode electrode 37, which are light emission sources, are stacked on a substrate 33 on which a pixel electrode 35 is formed. The circular polarizing plate 31 is disposed on the opposite side to the organic functional layer 36 with the substrate 33 interposed therebetween, and the circular polarizing plate 110 is used as the circular polarizing plate 31. The organic functional layer 36 emits light 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, which is a light emission source, is composed of an electron transport layer, a light emitting layer, and a hole transport layer. 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 circular polarizing plate 31 (this original polarizing plate 110). The organic EL display device having the organic functional layer 36 will be described, but it may be applied to an inorganic EL display device having an inorganic functional layer.

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

Subsequently, a circular polarizing plate 31 (this circular polarizing plate 110) is provided on a surface opposite to the surface on which the thin film transistor 40 of the substrate 33 is provided.

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

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

As the substrate 33, ceramic substrates such as a sapphire glass substrate, a quartz glass substrate, a soda glass substrate, and alumina; Metal substrates such as copper; And plastic substrates. Although not shown, a thermally conductive film may be formed on the substrate 33. A diamond thin film (DLC, etc.) etc. are mentioned as a heat conductive film. When the pixel electrode 35 is of a reflective type, light is emitted in a direction opposite to the substrate 33. Therefore, not only transparent materials, but also non-transparent materials such as stainless steel can be used. The substrate may be formed singly or may be formed as a laminated substrate by bonding a plurality of substrates with an adhesive. Moreover, these board|substrates are not limited to a plate-shaped thing, A film may be sufficient.

As the thin film transistor 40, a polycrystalline silicon transistor or the like may be used, for example. The thin film transistor 40 is provided at the end of the pixel electrode 35, and its size is about 10 to 30 µm. On the other hand, the size of the pixel electrode 35 is about 20 μm×20 μm to 300 μm×300 μm.

The wiring electrode of the thin film transistor 40 is provided on the substrate 33. The wiring electrode has a low resistance, and has a function of electrically connecting to the pixel electrode 35 to suppress the resistance value, and in general, the wiring electrode is Al, Al and transition metal (except Ti), Ti or nitride Any one or two or more of titanium (TiN) is used.

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

The ribs 41 are formed on the interlayer insulating film 34. The ribs 41 are arranged 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 ribs 41 is preferably 1.0 µm or more and 3.5 µm or less, and more preferably 1.5 µm or more and 2.5 µm or less.

Next, an EL element comprising a pixel electrode 35 as a transparent electrode, an organic functional layer 36 as a light emission source, and a cathode electrode 37 will be described. The organic functional layer 36 has at least one hole transport layer and a light emitting layer, respectively, for example, an electron injection transport layer, a light emitting layer, a hole transport layer, and a hole injection layer sequentially.

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 , and the like, particularly ITO or IZO. The thickness of the pixel electrode 35 may have a thickness equal to or greater than a predetermined level capable of sufficiently injecting holes, and is preferably about 10 to 500 nm.

The pixel electrode 35 can be formed by a vapor deposition 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 the 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, it is preferable to use a two-component or three-component alloy system selected from the illustrated 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) ∼20 at%) and the like are preferred.

The cathode electrode 37 is formed by a vapor deposition method, a sputtering method, or the like. The thickness of the cathode electrode 37 is preferably 0.1 nm or more, preferably 1 to 500 nm.

The hole injection layer has a function of facilitating injection of holes from the pixel electrode 35, and the hole transport layer has a function of transporting holes and a function of interfering electrons, and is also called a charge injection layer or a charge 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 vary depending on the formation method, but are preferably about 5 to 100 nm. Various organic compounds can be used for the hole injection layer and the hole transport layer. A vacuum deposition method can be used in that a homogeneous thin film can be formed to form the hole injection transport layer, the light emitting layer, and the electron injection transport layer.

As the organic functional layer 36, which is a light emission source, using light emission (fluorescence) from singlet excitons, using light emission (phosphorescence) from triplet excitons, using light emission (fluorescence) from singlet excitons and triplet excitons Using light emission (phosphorescence) from, including those formed by organic substances, those formed by organic substances and those formed by inorganic substances, including polymer materials, low-molecular materials, high-molecular materials and low-molecular materials. Can be used. However, the present invention is not limited to this, and the organic functional layer 36 using various known ones for EL elements can be used in the present EL display device 30.

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 weak to humidity. The desiccant 38 absorbs moisture to prevent deterioration of the organic functional layer 36.

10 is a schematic diagram showing a cross-sectional configuration of another aspect of the EL display device 30. As shown in FIG. This EL display device 30 has a sealing structure using a thin film sealing film 42, and it is also possible to obtain emitted light from the opposite side of the array substrate.

As the thin film sealing film 42, it is preferable to use a DLC film obtained by depositing DLC (diamond-like carbon) on a film of an electrolytic capacitor. The DLC film has a property that water permeability is very poor and has high moisture-proof performance. Further, a DLC film or the like may be formed by directly depositing the surface of the cathode electrode 37. Further, the thin resin film and the metal thin film may be stacked in multiple layers to form a thin film sealing film 42.

As described above, a novel polarizing film (this polarizing film) and a novel display device (this liquid crystal display device and this EL display device) provided with the polarizing film according to the present invention are provided.

Finally, the projection type liquid crystal display device using this polarizing film is demonstrated.

11 is a schematic diagram showing a projection type liquid crystal display device using the present polarizing film.

The polarizing film seen as the polarizer 142 and/or the polarizer 143 of this projection type liquid crystal display device is used.

The bundle of light rays emitted from the light source (for example, a high-pressure mercury lamp) 111, which is a light emission source, firstly includes a first lens array 112, a second lens array 113, a polarization conversion element 114, and a superposition lens 115. By passing, uniformity of luminance and polarization of anti-ray bundles are achieved.

Specifically, the bundle of light beams emitted from the light source 111 is divided into a plurality of small bundles of light beams by the first lens array 112 in which the minute lenses 112a are formed in a matrix form. The second lens array 113 and the superimposed lens 115 are provided so as to illuminate all three liquid crystal panels 140R, 140G, and 140B, each of which is an object to be illuminated, for this reason, each liquid crystal panel incident side The surface becomes roughly uniform throughout.

The polarization conversion element 114 is constituted by a polarization beam splitter array, and is disposed between the second lens array 113 and the overlapping lens 115. Accordingly, the random polarization from the light source is converted into polarized light having a specific polarization direction in advance, thereby reducing the amount of light loss at the incident side polarizer, which will be described later, and serves to improve the brightness of the screen.

As described above, the luminance uniformized and polarized light is sequentially red channel, green channel, and blue channel by dichroic mirrors 121, 123, and 132 for separating into three primary colors of RGB via the reflection mirror 122. Separated by, and enters the liquid crystal panel (140R, 140G, 140B), respectively.

In the liquid crystal panels 140R, 140G, and 140B, polarizers 142 are disposed on the incident side, and polarizers 143 are disposed on the exit side, respectively. The polarizing film seen in the polarizer 142 and the polarizer 143 can be used.

The polarizer 142 and the polarizer 143 disposed in each of the RGB optical paths are arranged such that their respective absorption axes are orthogonal. Each of the liquid crystal panels 140R, 140G, and 140B disposed in each optical path has a function of converting a polarized state controlled for each pixel by an image signal into an amount of light.

The polarizing film 100 is useful as a polarizing film having excellent durability in an optical path such as a blue channel, a green channel, and a red channel by selecting a type of a dichroic dye suitable for a corresponding channel.

The optical image created by transmitting incident light at a different transmittance for each pixel according to the image data of the liquid crystal panels 140R, 140G, 140B is synthesized by the cross dichroic prism 150, and the screen 180 is projected by the projection lens 170. Projected on enlarged.

Electronic papers are those represented by molecules such as optical anisotropy and dye molecular orientation, those represented by particles such as electrophoresis, particle movement, particle rotation, phase change, those displayed by one end of the film moving, What is indicated by a color change/phase change, what is shown by light absorption of a molecule, what is shown by self-lighting when electrons and holes are combined, etc. are mentioned. More specifically, microcapsule type electrophoresis, horizontally movable electrophoresis, vertically movable electrophoresis, spherical twisted ball, magnetically twisted ball, circumferentially twisted ball method, charged toner, electron powder fluid, magnetophoretic type, magnetic direct heating, electro Wetting, light scattering (transparent/cloudy change), cholesteric liquid crystal/photoconductive layer, cholesteric liquid crystal, bistable nematic liquid crystal, ferroelectric liquid crystal, dichroic dye/liquid crystal dispersion type, movable film, color repelling by leuco dye, Photochromic, electrochromic, electrodeposition, flexible organic EL, and the like. The electronic paper may be used not only for personal use of text or images, but also used for advertisement signs and the like. According to this polarizing film, the thickness of the electronic paper can be made thin.

As a stereoscopic display device, a method of arranging different phase difference films alternately such as a micropole method has been proposed (Japanese Patent Laid-Open No. 2002-185983), but patterning by printing, inkjet, photolithography, etc. is possible using this polarizing film. Since it is easy, the manufacturing process of a display device can be shortened, and a retardation film is unnecessary.

Example

Hereinafter, the present invention will be described in more detail by examples. "%" and "part" in the examples are mass% and mass parts, unless otherwise specified.

The following dichroic dye (1) was used in this example.

Preparation of compound (1-1) (compound represented by (1-1) below)

Compound (1-1) was synthesized by the following scheme.

A compound represented by formula (1B) [Compound (1B)] 5.00 g, 4-hydroxyethyl benzoate 4.63 g, dimethylaminopyridine (DMAP) 0.23 g and 25 g of chloroform were mixed, and in a light-shielding nitrogen atmosphere, 5°C The mixture was stirred for 10 minutes. To the obtained mixed solution, 2.58 g of diisopropylcarbodiimide (IPC) was added dropwise over 5 minutes and stirred for 4 hours. To the obtained reaction solution, 75 g of methanol was added, crystallized, and the crystal was filtered. After further washing the crystals with the same amount of methanol, 6.78 g of compound (1-1) was obtained by vacuum drying. The yield was 87% based on compound (1B).

¹ H-NMR (CDCl ₃ ) of compound (1-1): δ (ppm) 1.41 (t, 3H), 3.12 (s, 6H), 4.40 (m, 2H), 6.76 (m, 2H), 7.33 ( m, 2H), 7.93 (dd, 4H), 8.15 (m, 2H), 8.30 (m, 2H).

Preparation of compound (1-7) (compound represented by the following (1-7))

Compound (1-7) was synthesized by the following scheme.

5.00 g of compound (1B), 4.63 g of 4-butyloxyphenol, 0.23 g of DMAP and 25 g of chloroform were mixed and stirred at 5°C for 10 minutes in a light-shielding/nitrogen atmosphere. 2.58 g of IPC was added dropwise to the obtained mixed solution over 5 minutes, and further stirred for 4 hours. 75 g of methanol was added to the obtained reaction solution, crystallized, and the crystal was filtered. The crystal was dissolved in 50 g of dimethylacetamide, and the insoluble matter was filtered through celite. The filtrate was recovered and crystallized with water. The obtained crystals were also dissolved in 50 g of tetrahydrofuran to remove insoluble matters by filtration, and then heptane was added to crystallize and vacuum dried to obtain 4.66 g of compound (1-7). The yield was 60% based on compound (1B).

¹ H-NMR (CDCl ₃ ) of compound (1-7): δ (ppm) 0.99 (t, 3H), 1.45 (m, 2H), 1.78 (m, 2H), 3.12 (s, 6H), 3.98 ( t, 2H), 6.77 (m, 2H), 6.93 (m, 2H), 7.15 (m, 2H), 7.92 (dd, 4H), 8.29 (dd, 2H).

The following polymerizable liquid crystal compound was used in this example.

Compound (4-6) (compound represented by the following formula (4-6))

Compound (4-6) was prepared by 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 (4-6) was confirmed by obtaining the phase transition temperature of the membrane composed of the compound (4-6). The operation is as follows.

A film composed of compound (4-6) was formed on a glass substrate on which an alignment film was formed, and the phase transition temperature was confirmed by heating and observing the texture with a polarizing microscope (BX-51, manufactured by Olympus). The film composed of the compound (4-6), after raising the temperature to 120° C., when lowering the temperature, phase-transfers to the nematic phase at 112° C., phase-transfers to the smectic A phase at 110° C., and smectic at 94° C. Phase transition to phase B.

Compound (4-8) (compound represented by the following formula (4-8))

Compound (4-8) was synthesized with reference to the synthesis method of compound (4-6) described above.

(Measurement of phase transition temperature)

In the same manner as in the measurement of the phase transition temperature of compound (4-6), the phase transition temperature of compound (4-8) was confirmed. Compound (4-8), after raising the temperature to 140 ℃, when the temperature is lowered, phase transition from 131 ℃ to the nematic phase, phase transition from 80 ℃ to the smectic A phase, from 68 ℃ to the smectic B phase Phase transition.

Compound (4-22) (compound represented by the following formula (4-22))

Compound (4-22) was synthesized with reference to the synthesis method described in Japanese Patent No. 4719156.

(Measurement of phase transition temperature)

In the same manner as in the measurement of the phase transition temperature of compound (4-6), the phase transition temperature of compound (4-22) was confirmed. Compound (4-22), after raising the temperature to 140 ℃, when the temperature is lowered, the phase transition from 106 ℃ to the nematic phase, phase transition from 103 ℃ to the smectic A phase, from 86 ℃ to the smectic B phase Phase transition.

Compound (4-25) (compound represented by the following formula (4-25))

Compound (4-25) was synthesized with reference to the synthesis method described in Japanese Patent No. 4719156.

(Measurement of phase transition temperature)

In the same manner as in the measurement of the phase transition temperature of compound (4-6), the phase transition temperature of compound (4-25) was confirmed. Compound (4-25), after raising the temperature to 140°C, when lowering the temperature, phase-transfers from 119°C to the nematic phase, phase-transfers from 100°C to the smectic A phase, and 77°C to the smectic B phase. Phase transition.

Example 1 [Preparation of composition (A) for polarizing film formation]

The composition (A) for polarizing film formation was obtained by mixing the following components and stirring at 80 degreeC for 1 hour. Meanwhile, the term "compound (1-7)" of the dichroic dye used herein means a compound represented by the above formula (1-7), and the compound used as another dichroic dye also conforms to the formula number. The same applies to the following.

Polymerizable liquid crystal compounds; Compound (4-6) 75 parts

Compound (4-8) 25 parts

Dichroic pigments; Compound (1-7) 3.0 parts

Compound (2-17) 2.5 parts

Compound (2-29) 1.5 parts

Compound (2-32) 2.0 parts

Polymerization initiators; 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Chiba Specialty Chemicals) 6 parts

Leveling agents; Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) 1.2 parts

solvent; 250 parts of toluene

1. X-ray diffraction measurement

A 2 mass% aqueous solution (a composition for forming an alignment layer) of polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified, manufactured by Wako Pure Chemical Industries, Ltd.) was coated on a glass substrate by spin coating, dried, and then thick. A 100 nm film was formed. Next, an alignment layer was formed by performing a rubbing treatment on the surface of the obtained film. The rubbing treatment was performed using a semi-automatic rubbing device (trade name: LQ-008 type, manufactured by Joyo Kogaku Co., Ltd.), and the indentation amount was 0.15 mm by cloth (trade name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.). , 500 rpm, 16.7 mm/s. The composition (A) for forming a polarizing film was coated on the alignment film thus produced by spin coating, heated and dried on a hot plate at 120°C for 1 minute, rapidly cooled to room temperature, and dried on the alignment layer. A film was formed. Subsequently, using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.), ultraviolet rays are irradiated to the dry film at an exposure dose of 2000 mJ/cm 2 (based on 365 nm), whereby the polymerizability contained in the dry film The liquid crystal compound was polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal composition, and a polarizing film was formed from the dried film. The thickness of the polarizing film at this time was measured by a laser microscope (OLS3000 manufactured by Olympus Co., Ltd.), and was 1.7 µm. As for the polarizing film, X-ray diffraction measurement was similarly performed using an X-ray diffraction apparatus X'Pert PRO MPD (manufactured by Spectris Co., Ltd.), and as a result, peak half-width (FWHM) = about 0.17° near 2θ=20.2°. A sharp diffraction peak (Bragg peak) was obtained. Moreover, the same result was obtained also from the incidence from the rubbing vertical direction. The order period (d) obtained from the peak position was about 4.4 Hz, and it was confirmed that a structure reflecting the higher order smectic phase was formed.

2. Preparation of light alignment film on transparent film

Using a triacetyl cellulose film (KC8UX2M, manufactured by Konica Minolta Co., Ltd.) as a transparent substrate, a solution obtained by dissolving 5% of the photo-alignment polymer represented by the following formula (3) in toluene was applied by a bar coat method, 120 It was dried at ℃ to obtain a dry film. Polarized UV was irradiated on this dry film to obtain a photo-alignment film. The polarized UV treatment was performed under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.).

3. Preparation of polarizing film

On the film having the photo-alignment film obtained as described above, the composition for polarizing film formation (A) was applied by a bar coat method (#5 17 mm/s), and heated and dried in a drying oven at 120° C. for 1 minute. , Cooled to room temperature. Subsequently, by using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.), ultraviolet rays having an exposure amount of 2000 mJ/cm 2 (based on 365 nm) are irradiated onto a layer formed of a composition for forming a polarizing film, and dried. 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. It was 1.6 micrometers when the film thickness of the polarizing film at this time was measured with the laser microscope (OLS3000 by Olympus Co., Ltd.). What was obtained in this way is a polarizer containing a polarizing film and a transparent substrate.

4. Measurement of polarization degree, transmittance and color

In order to confirm the usefulness of the polarizer, the luminous corrected polarization degree, luminous corrected transmittance, chromaticity a* value, chromaticity b* value, orthogonal a* and orthogonal b* were measured as follows.

Set the transmittance (T ¹ ) in the transmission axis direction and the transmittance (T ² ) in the absorption axis direction in the wavelength range of 380 nm to 780 nm, and set a folder with a polarizer in a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation) It was measured by the double beam method using one apparatus. In the folder, the reference side installed a mesh that cuts the amount of light by 50%. The following formulas (Formula 1) and (Formula 2) were used to calculate the monolithic transmittance and polarization degree at each wavelength, and further corrected the visibility by performing a two-degree field of view (C light source) of JIS Z 8701 to correct the visibility. The transmittance (Ty) and the visibility correction polarization (Py) were calculated. The chromaticity a* and b* in the L*a*b*(CIE) colorimetric system were calculated from the monochromatic transmittance of the C light source from the monolithic transmittance measured in the same manner. Moreover, orthogonal a* and orthogonal b* in the L*a*b*(CIE) colorimetric system were calculated from the orthogonal transmittance measured similarly using the isochromatic function of the C light source. The chromaticity a*, chromaticity b*, orthogonal a*, and orthogonal b* may be judged to be neutral colors as the value approaches 0. Table 4 shows these results.

Monolithic transmittance (%)=(T1+T2)/2 (Equation 1)

Polarization degree (%)=(T1-T2)/(T1+T2)×100 (Equation 2)

Example 2

1. Preparation of polarizing film

A polarizing film was produced in the same manner as in Example 1 except that the bar width of the bar coater and the coating speed were changed (#7 15 mm/s). It was 1.8 micrometers when the film thickness of the polarizing film at this time was measured with the laser microscope (OLS3000 by Olympus Co., Ltd.).

2. Measurement of polarization degree, transmittance and color

Table 4 shows the results obtained by measuring the luminous transmittance (Ty) and the luminous corrected polarization (Py) and chromaticity a*, chromaticity b*, orthogonal a*, and orthogonal b* of the prepared polarizing film in the same manner as in Example 1. Shows.

Example 3 [Preparation of composition (B) for polarizing film formation]

The composition (B) for polarizing film formation was obtained by mixing the following components and stirring at 80 degreeC for 1 hour.

Polymerizable liquid crystal compounds; Compound (4-22) 75 parts

Compound (4-25) 25 parts

Dichroic pigments; Compound (1-1) 3.0 parts

Compound (2-15) 2.5 parts

Compound (2-20) 1.2 parts

Compound (2-33) 2.5 parts

Polymerization initiators; 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Chiba Specialty Chemicals) 6 parts

Leveling agents; Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) 1.2 parts

solvent; 250 parts of toluene

1. Preparation of polarizing film

In the same manner as in Example 1, except that the composition for forming a polarizing film (A) was changed to the composition for forming a polarizing film (B), and the wire width and coating speed of the bar of the bar coater were changed (#5 25 mm/s). To prepare a polarizing film. It was 1.7 micrometers when the film thickness of the polarizing film at this time was measured with the laser microscope (OLS3000 by Olympus Co., Ltd.).

2. Measurement of polarization degree, transmittance and color

Table 4 shows the results obtained by measuring the luminous transmittance (Ty) and the luminous corrected polarization (Py) and chromaticity a*, chromaticity b*, orthogonal a*, and orthogonal b* of the prepared polarizing film in the same manner as in Example 1. Shows.

Example 4

1. Preparation of polarizing film

A polarizing film was produced in the same manner as in Example 3 except that the bar width of the bar coater and the coating speed were changed (#7 20 mm/s). It was 2.0 micrometers when the film thickness of the polarizing film at this time was measured with the laser microscope (OLS3000 by Olympus Co., Ltd.).

2. Measurement of polarization degree, transmittance and color

Table 4 shows the results obtained by measuring the luminous transmittance (Ty) and the luminous corrected polarization (Py) and chromaticity a*, chromaticity b*, orthogonal a*, and orthogonal b* of the prepared polarizing film in the same manner as in Example 1. Shows.

Example 5

1. Preparation of black polarizing film

A polarizing film was produced in the same manner as in Example 3 except that the bar width of the bar coater and the coating speed were changed (#5 50 mm/s). It was 2.2 micrometers when the film thickness of the polarizing film at this time was measured with the laser microscope (OLS3000 by Olympus Co., Ltd.).

2. Measurement of polarization degree, transmittance and color

Table 4 shows the results obtained by measuring the luminous transmittance (Ty) and the luminous corrected polarization (Py) and chromaticity a*, chromaticity b*, orthogonal a*, and orthogonal b* of the prepared polarizing film in the same manner as in Example 1. Shows.

Example 6 [Preparation of composition (C) for polarizing film formation]

The composition (C) for polarizing film formation was obtained by mixing the following components and stirring at 80 degreeC for 1 hour.

Polymerizable liquid crystal compounds; Compound (4-6) 75 parts

Compound (4-8) 25 parts

Dichroic pigments; Compound (1-1) 3.6 parts

Compound (2-15) 3.0 parts

Compound (2-18) 1.5 parts

Compound (2-27) 2.0 parts

Compound (2-32) 1.5 parts

Polymerization initiators; 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Chiba Specialty Chemicals) 6 parts

Leveling agents; Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) 1.2 parts

solvent; 250 parts of toluene

1. Preparation of polarizing film

In the same manner as in Example 1, except that the composition (A) for forming the polarizing film was changed to the composition (C) for forming the polarizing film, and the wire width and coating speed of the bar of the bar coater were changed (#7 20 mm/s). To prepare a polarizing film. It was 2.0 micrometers when the film thickness of the polarizing film at this time was measured with the laser microscope (OLS3000 by Olympus Co., Ltd.).

2. Measurement of polarization degree, transmittance and color

Table 4 shows the results obtained by measuring the luminous transmittance (Ty) and the luminous corrected polarization (Py) and chromaticity a*, chromaticity b*, orthogonal a*, and orthogonal b* of the prepared polarizing film in the same manner as in Example 1. Shows.

Example 7

1. Preparation of black polarizing film

A polarizing film was produced in the same manner as in Example 6 except that the bar width of the bar coater and the coating speed were changed (#5 50 mm/s). It was 2.2 micrometers when the film thickness of the polarizing film at this time was measured with the laser microscope (OLS3000 by Olympus Co., Ltd.).

2. Measurement of polarization degree, transmittance and color

Table 4 shows the results obtained by measuring the luminous transmittance (Ty) and the luminous corrected polarization (Py) and chromaticity a*, chromaticity b*, orthogonal a*, and orthogonal b* of the prepared polarizing film in the same manner as in Example 1. Shows.

Comparative Example 1

1. Preparation of iodine-PVA polarizer

The polyvinyl alcohol film having an average polymerization degree of about 2,400 and a saponification degree of at least 99.9 mol% and a thickness of 75 µm is uniaxially stretched about 5 times by dry type, and immersed in 60°C pure water for 1 minute while maintaining tension. / Potassium iodide/water was immersed in an aqueous solution having a mass ratio of 0.1/5/100 at 28°C for 60 seconds. Thereafter, the aqueous solution having a potassium iodide/boric acid/water mass ratio of 810.5/7.5/100 was immersed at 72°C for 300 seconds. Then, after washing for 5 seconds with pure water at 10°C, drying was performed at 80°C for 3 minutes to obtain a polarizer in which iodine was adsorbed and oriented on a polyvinyl alcohol resin film.

2. Measurement of polarization degree, transmittance and color

Table 4 shows the results of measuring the monochromatic transmittance (Ty) and the luminous correction (Py) and chromaticity a*, chromaticity b*, orthogonal a*, and orthogonal b* of the prepared polarizer in the same manner as in Example 1. Shows.

As can be seen from Table 4, any of the polarizing films of Examples 1 to 7 was thinner than the conventional iodine-PVA polarizer. In addition, the polarizing films of Examples 1 to 7 showed neutral color properties.

Example 8

1. Preparation of optical alignment film on retardation film

As a transparent substrate, instead of a triacetyl cellulose film (KC8UX2M, manufactured by Konica Minolta Co., Ltd.), a retardation film (uniaxially stretched film WRF-S (modified polycarbonate-based resin), a retardation value of 137.5 nm, a thickness of 50 μm, Teijin Kasei Co., Ltd. ) Production), a solution obtained by dissolving 5% of the photo-alignment polymer represented by the formula (3) in cyclopentanone was applied by a bar coat method, and dried at 120°C to obtain a dry film. Polarized UV was irradiated on this dry film to obtain a photo-alignment film. The polarized UV treatment was performed under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.). In addition, at this time, the irradiation direction of the polarized UV was performed to be 45° with respect to the slow axis of the retardation film.

2. Production of circular polarizing plate

After applying the composition (C) for forming a polarizing film on the photo-alignment film of the retardation film having the prepared photo-alignment film by a bar coat method (#7 20 mm/s), and heated and dried in a drying oven at 120° C. for 1 minute, Cooled to room temperature. Subsequently, by using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.), ultraviolet rays having an exposure amount of 2000 mJ/cm 2 (based on 365 nm) are irradiated to a layer formed of a composition for forming a polarizing film, and dried. A circularly polarizing plate was produced by polymerizing the polymerizable liquid crystal compound contained in the film while maintaining the liquid crystal state of the polymerizable liquid crystal composition and forming a polarizing film with the dry film. It was 2.0 micrometers when the film thickness of the polarizing film at this time was measured with the laser microscope (OLS3000 by Olympus Co., Ltd.).

3. Confirmation of anti-reflection performance

When the phase difference film side of the obtained circularly polarizing plate and the aluminum metal plate were bonded together through an adhesive, the metallic luster observed in the aluminum metal plate single body was lost, and a uniform black display was obtained. Thus, it can be seen that the circular polarizing plate made of the present polarizing film has good antireflection properties.

This polarizing film is very useful in manufacturing a liquid crystal display device, (organic) EL display device, and projection type liquid crystal display device.

1: transparent substrate 2: light alignment film
3: present polarizing film 4: retardation layer
100: present polarizer 210: first roll
210A: winding core 220: second roll
220A: winding core 230: third roll
230A: winding core 240: fourth roll
240A: winding core 211A, 211B: coating device
212A, 212B: Drying furnace 213A: Polarized UV irradiation device
213B: light irradiation device 300: auxiliary roll
10: liquid crystal display device 11: surface protective layer
12a, 12b: polarizer 13a, 13b: retardation layer
14a, 14b: Substrate 15: Color filter
16: transparent electrode 17: liquid crystal layer
18: interlayer insulating film 19: backlight unit
20: black matrix 21: thin film transistor
22: pixel electrode 23: spacer
30: EL display device 31: circular polarizing plate
32: retardation film 33: substrate
34: interlayer insulating film 35: pixel electrode
36: organic functional layer 37: cathode electrode
38: desiccant 39: sealing lid
40: thin film transistor 41: rib
42: thin film sealing film 44: EL display device
111: light source 112: first lens array
112a: lens 113: second lens array
114: polarization conversion element 115: superposition lens
121, 123, 132: dichroic mirror 122: reflective mirror
140R, 140G, 140B: liquid crystal panel 142, 143: polarizer
150: cross dichroic prism 170: projection lens
180: screen

Claims (15)

A polymer formed of a polymerizable liquid crystal compound, and when the light absorption is measured by dispersing in the polymer, at least one dichroic dye (1) having a maximum absorption in the wavelength range of 380 to 550 nm and a wavelength of 550 to A polarizing film comprising at least two dichroic dyes (2) having a maximum absorption in the range of 700 nm,
The polarizing film has a Bragg peak in the X-ray diffraction measurement,
A polarizing film in which the polymerizable liquid crystal compound is a compound exhibiting a smectic liquid crystal phase. The polarizing film according to claim 1, wherein the dichroic dye (1) is dispersed in a polymer formed of a polymerizable liquid crystal compound to measure light absorption and has a maximum absorption in a range of 400 to 550 nm in wavelength. The dichroic dye (2) according to claim 1, wherein at least two dichroic dyes (2) having absorption maxima in the range of wavelengths 550 to 700 nm are measured when light absorption is measured by dispersing in the polymer.
When the light absorption is measured by dispersing in the polymer,
A dichroic dye (2-1) having a maximum absorption in a wavelength range of 550 to 600 nm,
A polarizing film comprising a dichroic dye (2-2) having a maximum absorption in a range of 600 to 700 nm in wavelength. delete delete The color coordinate a* value and b* value in the L*a*b* colorimetric system according to any one of claims 1 to 3 satisfy the relationship of the following expressions (1F) and (2F). Polarizing film.
-3≤ Chromaticity a*≤3 (1F)
-3≤ Chromaticity b*≤3 (2F) The polarizing film according to any one of claims 1 to 3, wherein the dichroic dye (1) and the dichroic dye (2) are azo compounds. The polarizing film according to any one of claims 1 to 3, wherein the dichroic dye (2) is composed of a compound represented by formula (2).

[In formula (2), n is 1 or 2.
Ar ¹ and Ar ³ are groups independently represented by any of formulas (AR-1) to (AR-4).

Ar ² is a group represented by formula (AR2-1), formula (AR2-2) or formula (AR2-3).

A ₁ and A ₂ are each independently a group represented by any of formulas (A-1) to (A-9), and * represents a bond number.

(mc is an integer from 0 to 10, and when there are two mcs in the same group, the two mcs are the same or different from each other.)] The polarizing film according to any one of claims 1 to 3, wherein the dichroic dye (1) is composed of a compound represented by formula (1).

[In Formula (1), Y is a group represented by Formula (Y1) or Formula (Y2).

(In the formula, L is an oxygen atom or -NR-, and R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
R ¹ is a group represented by any of formulas (R ¹ -1) to (R ¹ -3).

(In the formula, ma is an integer from 0 to 10, and when there are two ma in the same group, the two ma are the same or different from each other. * represents the number of bonds.)
R ² is a group represented by any of formulas (R ² -1) to (R ² -6).

(In the formula, mb is an integer from 0 to 10.)] A polarizer formed by forming the polarizing film according to any one of claims 1 to 3 on a transparent substrate. As a manufacturing method of the polarizer according to claim 10,
The process of preparing a laminated body provided with an alignment film on a transparent substrate,
A dichroic dye having an absorption maximum in the range of wavelength 380 to 550 nm when dispersed in a polymer formed of a polymerizable liquid crystal compound and a polymer formed of the polymerizable liquid crystal compound on the alignment layer of the laminate to measure light absorption. (1) a process of applying a composition comprising one type, two types of dichroic dyes (2) having absorption maxima in the range of wavelengths 550 to 700 nm, and a solvent,
Process for polymerizing the polymerizable liquid crystal compound contained in the composition
Manufacturing method having a. The manufacturing method according to claim 11, wherein the transparent substrate is a plastic substrate, and the alignment film is a photo-alignment film. A liquid crystal display device comprising the polarizing film according to any one of claims 1 to 3. A circular polarizing plate having the polarizing film and λ/4 layer according to any one of claims 1 to 3, and satisfying the following requirements of (A1) and (A2).
(A1) the angle between the absorption axis of the polarizing film and the slow axis of the λ/4 layer should be 45°;
(A2) The value of the front retardation of the λ/4 layer measured with light having a wavelength of 550 nm should be in the range of 100 to 150 nm. An organic EL display device comprising the circular polarizing plate according to claim 14 and an organic EL element.

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