TWI622814B - Polarizing film, circular polarizing plate and manufacturing method thereof - Google Patents

Abstract

The present invention provides a polarizing film that is easy to be thinned and has excellent neutral hue, a polarizing element including the polarizing film, and a method of manufacturing the polarizing film.

The present invention provides a polarizing film, a polarizing element including the polarizing film, and a method of manufacturing the polarizing film. The polarizing film includes: a polymer formed of a polymerizable liquid crystal compound; and a situation in which light absorption is measured by being dispersed in the polymer. At least one dichroic pigment (1) having an absorption maximum in a wavelength range of 380 to 550 nm, and at least two dichroic pigments having an absorption maximum in a wavelength range of 550 to 700 nm ( 2). The dichroic pigment (2) is preferably a dichroic pigment having absorption in a wavelength range of 550 to 600 nm and a dichroic pigment having absorption in a wavelength range of 600 to 700 nm.

Description

Polarizing film, circular polarizing plate and manufacturing method thereof

The present invention relates to a method for manufacturing a polarizing film, a circularly polarizing plate, and the like.

The polarizing element used in liquid crystal display devices has both high transmittance and polarization, so it is widely used. Polyvinyl alcohol (iodine dyed PVA (Polyvinyl Alcohol) , Polyvinyl alcohol)) film (polarizing film). For example, Patent Document 1 describes a polarizing film containing iodine-stained PVA.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 7-142170

However, the polarizing film containing iodine-stained PVA has the problem of being easily yellowed, that is, the so-called neutral hue is poor. In addition, it is difficult to make a thin film of a polarizing film containing iodine-stained PVA, and there is a limit in application to a recent display device that requires a thinner thickness. Therefore, an object of the present invention is to provide a polarizing film that is easy to be thinned and has excellent neutral hue, a polarizing element including the polarizing film, and a method for manufacturing the same.

The present invention includes the following inventions.

[1] A polarizing film comprising: a polymer formed of a polymerizable liquid crystal compound; and when the light absorption is measured by being dispersed in the polymer, the wavelength is 380 to 550 nm At least one dichroic pigment (1) having an absorption maximum within the range, and at least two dichroic pigments (2) having an absorption maximum within a wavelength range of 550 to 700 nm.

[2] The polarizing film according to [1], in which the dichroic pigment (1) is dispersed in a polymer formed from a polymerizable liquid crystal compound to measure light absorption, in a wavelength range of 400 to 550 nm Has an absorption maximum.

[3] The polarizing film according to [1] or [2], wherein at least two kinds of dichroism having an absorption maximum in a wavelength range of 550 to 700 nm when measuring light absorption when dispersed in the polymer described above The pigment (2) includes a dichroic pigment (2-1) having an absorption maximum in a wavelength range of 550 to 600 nm when measuring light absorption when dispersed in the above polymer, and a wavelength of 600 to A dichroic pigment (2-2) with an absorption maximum in the 700 nm range.

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

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

[6] The polarizing film according to any one of [1] to [5], wherein the color coordinate a ^* value and b ^* value in the color system L ^* a ^* b ^* satisfy the following formulae (1F) and (2F) ) Relationship: -3 ≦ chroma a ^* ≦ 3 (1F)

-3 ≦ chroma b ^* ≦ 3 (2F).

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

[8] The polarizing film according to any one of [1] to [7], wherein the dichroic pigment (2) contains a compound represented by the formula (2):

[In formula (2), n is 1 or 2; Ar ¹ and Ar ³ are each independently a base represented by any one of formulas (AR-1) to (AR-4):

Ar ² is a base represented by formula (AR2-1), formula (AR2-2), or formula (AR2-3):

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

(mc is an integer from 0 to 10, and when there are two mcs in the same base, 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 pigment (1) includes a compound represented by the formula (1):

[In formula (1), Y is a base 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 base represented by any one of the formulae (R ¹ -1) to (R ¹ -3):

(In the formula, ma is an integer from 0 to 10. When there are two ma in the same base, the two ma are the same or different from each other; * represents a bond bond)

R ² is a base represented by any one of formulas (R ² -1) to (R ² -6):

(Where mb is an integer from 0 to 10)].

[10] A polarizing element, which is formed by disposing a polarizing film according to any one of [1] to [9] on a transparent substrate.

[11] A manufacturing method, which is the manufacturing method of a polarizing element as in [10], and includes: a step of preparing a laminated body including an alignment film on a transparent substrate; and applying a combination on the above-mentioned alignment film of the laminated body The composition comprises: a polymerizable liquid crystal compound; and when the light absorption is measured by dispersing in a polymer formed from the polymerizable liquid crystal compound, it has an absorption maximum in a range of 380 to 550 nm. 1 dichroic pigment (1), 2 dichroic pigments (2) having absorption maximum in a wavelength range of 550 to 700 nm; and a solvent; and the aforementioned polymerizable property contained in the composition Step of polymerizing a liquid crystal compound.

[12] The manufacturing 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 including the polarizing film according to any one of [1] to [9].

[14] A circular polarizing plate comprising the polarizing film and the λ / 4 layer as in any one of [1] to [9], and satisfying the following requirements of (A1) and (A2): (A1) the above-mentioned polarizing film The angle formed by the absorption axis and the late phase axis of the λ / 4 layer is approximately 45 °; (A2) The value of the front retardation of the λ / 4 layer measured by light with a wavelength of 550 nm is in the range of 100 to 150 nm.

[15] An organic EL (Electroluminescence, electroluminescence) display device including a circular polarizing plate as in [14] and an organic EL element.

According to the present invention, it is possible to provide a polarizing film that is easy to be thinned and has excellent neutral hue and a polarizing element including the polarizing film.

1‧‧‧ transparent substrate

2‧‧‧light alignment film

3‧‧‧ this polarizing film

4‧‧‧ phase difference layer

10‧‧‧ Liquid crystal display device

11‧‧‧ surface protection layer

12a, 12b‧‧‧polarizing element

13a, 13b ‧‧‧ retardation layer

14a, 14b‧‧‧ substrate

15‧‧‧ color filter

16‧‧‧ transparent electrode

17‧‧‧LCD layer

18‧‧‧ interlayer insulation film

19‧‧‧ backlight unit

20‧‧‧ Black Matrix

21‧‧‧ thin film transistor

22‧‧‧pixel electrode

23‧‧‧ spacer

30‧‧‧EL display device

31‧‧‧circular polarizer

32‧‧‧ retardation film

33‧‧‧ substrate

34‧‧‧Interlayer insulation film

35‧‧‧pixel electrode

36‧‧‧Organic Functional Layer

37‧‧‧ cathode electrode

38‧‧‧ Desiccant

39‧‧‧Sealing cover

40‧‧‧ thin film transistor

41‧‧‧ rib

42‧‧‧film sealing film

44‧‧‧EL display device

100‧‧‧ this polarizing element

110‧‧‧ circular polarizer

111‧‧‧light source

112‧‧‧1st lens array

112a‧‧‧lens

113‧‧‧ 2nd lens array

114‧‧‧Polarization conversion element

115‧‧‧ overlapping lens

121, 123, 132‧‧‧ dichroic mirrors

122‧‧‧Mirror

140R, 140G, 140B‧‧‧ LCD panel

142, 143‧‧‧polarizing elements

150‧‧‧ Cross dichroism

170‧‧‧ projection lens

180‧‧‧Screen

210‧‧‧Reel 1

210A‧‧‧ core

211A, 211B‧‧‧ coating device

212A, 212B‧‧‧drying furnace

213A‧‧‧polarized UV irradiation device

213B‧‧‧light irradiation device

220‧‧‧Reel 2

220A‧‧‧roll core

230‧‧‧3rd reel

230A‧‧‧ core

240‧‧‧4th reel

240A‧‧‧ core

300‧‧‧ auxiliary roller

A‧‧‧Enlarged section

B‧‧‧ enlarged part

C‧‧‧Enlarged part

D1‧‧‧ direction

D2‧‧‧ direction

FIG. 1 is a schematic diagram of a continuous manufacturing method of a polarizing element (this polarizing element) including a polarizing film of the present invention.

FIG. 2 is a schematic diagram showing the relationship between the alignment direction D2 of the optical alignment film and the film transport direction D1.

FIG. 3 is a schematic view showing a cross-sectional structure of a liquid crystal display device using the polarizing film of the present invention.

4 (A1) and (A2) are schematic diagrams showing a layer sequence of the present polarizing element used in the liquid crystal display device of FIG. 3.

5 (B1) and (B2) are schematic diagrams showing a layer sequence of the present polarizing element used in the liquid crystal display device of FIG. 3.

FIG. 6 is a schematic view showing a cross-sectional structure of an EL display device using the polarizing film of the present invention.

7 (A) and 7 (B) are schematic diagrams showing a cross-sectional structure of an embodiment of the present polarizing element including the polarizing film of the present invention.

FIG. 8 is a schematic view showing an example of a continuous manufacturing method of a circularly polarizing plate (this circularly polarizing plate) including the polarizing film of the present invention.

9 (C1) and (C2) are schematic diagrams showing a layer sequence of the present circular polarizing plate used in the EL display device of FIG. 6.

FIG. 10 is a schematic view showing a cross-sectional structure of an EL display device using the polarizing film of the present invention.

FIG. 11 is a schematic diagram showing a 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, sometimes referred to as "the present polarizing film") is characterized by including a polymer made of a polymerizable liquid crystal compound and three or more specific dichroic dyes. This polarizing film is preferably formed of a composition (hereinafter, sometimes referred to as a “polarizing film-forming composition”) containing a polymerizable liquid crystal compound and the three or more dichroic dyes. First, the composition for polarizing film formation is demonstrated.

1. Composition for forming polarizing film

As described above, 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, and further contains a solvent. The present polarizing film formed from such a polarizing film-forming composition is easily thinned. First, each component contained in the composition for polarizing film formation is demonstrated.

1-1. Dichroic pigment

The dichroic pigment contained in the polarizing film-forming composition includes a maximum absorption value in a range of 380 to 550 nm when measuring light absorption when dispersed in a polymer formed from a polymerizable liquid crystal compound. At least one dichroic pigment (1); and at least two dichroic pigments (2) having an absorption maximum in a wavelength range of 550 to 700 nm in the same measurement.

1-1-1. Dichroic pigment (1)

When the dichroic dye (1) is dispersed in a polymer formed from a polymerizable liquid crystal compound to measure light absorption, it has an absorption maximum in a range of 380 to 550 nm. In addition, this measurement may be performed as follows: The dichroic pigment in which the composition for polarizing film formation in the present invention is replaced with the dichroic pigment whose maximum absorption is to be measured is prepared. The composition for measuring a large absorption value is formed into a film for measuring absorption maximum by the same method as the method for forming the polarizing film from the composition for forming a polarizing film described below, and the light absorption of the film for measuring absorption maximum is measured. . The specific method for measuring the absorption maximum is the same as the method described in the examples of this case.

Examples of the dichroic dye (1) include an azo compound. Preferably, the compound represented by the said Formula (1) (henceforth a "compound (1)") is mentioned.

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

Y in the formula (1) is a base represented by the formula (Y1) or (Y2), and is preferably a base represented by the formula (Y1). In formula (Y1) and formula (Y2), the straight lines at both ends represent the bonding bond, the bond bond on the left side is bonded with phenyl group with azo group, the bond bond on the right side with benzene group with R ² Base bond. 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, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. Among them, L is preferably an oxygen atom or -NH-, and more preferably an oxygen atom.

R ¹ is a base 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 -3) The indicated base. The two ma in the base represented by the formula (R ¹ -2) may be the same or different, and are preferably the same. ma is further preferably an integer of 0 to 5.

R ² is formula (R ² -1), formula (R ² -2), formula (R ² -3), formula (R ² -4), formula (R ² -5) or formula (R ² -6) The base represented by the formula (R ² -2), the formula (R ² -5) or the formula (R ² -6) is more preferred, and the base represented by the formula (R ² -6) is more preferred base. When R ² is a base represented by formula (R ² -1), formula (R ² -2), formula (R ² -3), formula (R ² -5), or formula (R ² -6) The mb contained in the base is preferably an integer of 0 to 10, and further preferably an integer of 0 to 5.

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

Among them, compounds represented by formula (1-1), formula (1-2), formula (1-3), formula (1-5), formula (1-7) and formula (1-8) are preferred. Especially preferred are compounds represented by formula (1-1), formula (1-2), formula (1-3) and formula (1-7).

The dichroic pigment (1) has an absorption maximum at a wavelength of 380 to 550 nm, and preferably an absorption maximum at a wavelength of 400 to 550 nm, when the light absorption is determined by the above measurement. More preferably, it has an absorption maximum in a wavelength range of 400 to 520 nm, further preferably has an absorption maximum in a wavelength range of 430 to 520 nm, and even more preferably has an absorption maximum in a wavelength range of 440 to 510 nm. value. If it is within the above range If there is an absorption maximum in the compound, a plurality of compounds (1) may be used as the dichroic pigment (1).

Here, the manufacturing method of a compound (1) is demonstrated. The compound (1) can be produced, for example, from a compound represented by formula (1X) [compound (1X)] and a compound represented by formula (1Y) [compound (1Y)] by a reaction shown in the following scheme.

In the above drawings, R ¹ , R ² and Y have the same meanings as above, and Re ¹ and Re ² react with each other to form a base represented by Y. Examples of the combination of Re ¹ and Re ² include a combination of a carboxyl group and a hydroxyl group, a combination of a carboxyl group and an amine group (the amine group may be substituted by R), a combination of a halogen group and a hydroxyl group, a halogen group and an amine group (the A combination of an amine group may be substituted by R), a combination of a carbonyloxyalkyl group and a hydroxyl group, a combination of a carbonyloxy alkyl group and an amine group (the amine group may be substituted by R), and the like. Further, here, although the compound of R ¹ (1X) and the compound having a (1Y) R ² having the described, but it may also be protected by the compound to be suitable for the protective group R ^1, or a suitable protection of Compounds in which R ^{2 is} protected by a group react with each other, and then a suitable deprotection reaction is performed to produce a compound (1).

The reaction conditions at the time of reacting the compound (1X) and the compound (1Y) can be appropriately selected based on the types of the compound (1X) and the compound (1Y).

For example, the reaction conditions when Re ¹ is a carboxyl group, Re ² is a hydroxy group, and Y is -C (= O) -O- can be exemplified as conditions for performing condensation in a solvent in the presence of an esterification condensation agent. . Examples of the solvent include solvents that dissolve both the compound (1X) and the compound (1Y), such as chloroform. Examples of the esterification condensing agent include diisopropyl carbodiimide (IPC). Here, it is preferred to use a base such as dimethylaminopyridine (DMAP) in combination. The reaction temperature can be selected according to the type of the compound (1X) and the compound (1Y), and for example, a range of -15 to 70 ° C is preferable, and a range of 0 to 40 ° C is preferable. The reaction time is, for example, in the range of 15 minutes to 48 hours.

For the reaction time, the reaction mixture in the middle of the reaction may be appropriately sampled, and the degree of disappearance of the compound (1X) and the compound (1Y), or the compound ( 1) The degree of generation is confirmed and determined.

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

1-1-2. Dichroic pigment (2)

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

The dichroic pigment (2) contains two or more kinds in the composition for forming a polarizing film, and among them, the dichroic pigment (2-1) having a maximum absorption in a wavelength range of 550 to 600 nm and A dichroic pigment (2-2) with an absorption maximum in a wavelength range of 600 to 700 nm. Here, the dichroic pigment (2-1) preferably has an absorption maximum in a wavelength range of 570 to 600 nm, and the dichroic pigment (2-2) is further preferably in a wavelength of 600 to 680 nm. Within the range there is an absorption maximum.

Examples of the dichroic dye (2) include an azo compound. The dichroic dye (2) is preferably a compound represented by the above formula (2) (hereinafter, sometimes referred to as "compound (2)").

The geometric isomer of the azobenzene moiety of the compound (2) is preferably trans.

The compound (2) group of each of the combination, with the range of the compound (2) in the above assay at a wavelength of 550 ~ 60 ⁰ nm of the absorption maximum of the embodiment having a combination of Ar ^1, Ar ² and Ar ^3, The compound (2) which can be used as a dichroic pigment (2-1) can be determined. As a specific dichroic dye (2-1), the compound (2) shown by the combination of each group in Table 1 is mentioned. The compound (2-1) showing the combination of each group in Table 1 shows a case where n in the formula (2) is 1. In addition, in Table 1, the base etc. represented by Formula (AR-1) are described as "(AR-1)" etc., for example.

Then, in the combination of the groups of the compound (2), by combining Ar ¹ , Ar ^2, and Ar ³ in such a manner that the compound (2) has absorption in a range of a wavelength of 600 to 700 nm in the above measurement, it is possible to It was decided that the compound (2) could be used as a dichroic pigment (2-2). As a specific dichroic dye (2-2), the compound (2) shown by the combination of each group in Table 2 is mentioned. The compound (2-2) showing the combination of each group in Table 2 shows a case where n in the formula (2) is 1. The description of the bases in Table 2 is the same as that in Table 1.

Here, if the compound (2) is specifically represented, it can be enumerated by formula (2-11) to formula (2- 39).

In the specific examples of the compound (2) listed here, as the dichroic pigment (2-1), it is more appropriate to use formula (2-12), formula (2-13), formula (2-18), Formula (2-20), Formula (2-21), Formula (2-22), (2-23), (2-24), (2-26), (2-27), (2-28), (2-29), and ( 2-30), as the dichroic pigment (2-2), it is more suitable to use formula (2-31), formula (2-32), formula (2-33), and formula (2-34) ), Formula (2-35) and formula (2-36). In addition, although those represented by the formulas (2-11), (2-15), and (2-16) are not pigments that show absorption within a wavelength of 550 to 700 nm, they can be supplemented with the formula ( 1) The pigment is used in combination.

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

The content of the dichroic pigment (1) in the polarizing film-forming composition is expressed as a content relative to 100 parts by mass of the polymerizable liquid crystal compound described below, preferably 50 parts by mass or less, and more preferably 0.1 parts by mass or more. It is more preferably 0.1 parts by mass or more and 5 parts by mass or less.

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

The total content of the dichroic pigment (1) and the dichroic pigment (2) in the polarizing film-forming composition is expressed as a content relative to 100 parts by mass of the polymerizable liquid crystal compound described below, and is preferably 30 masses. It is more preferably 0.1 parts by mass or more and 20 parts by mass or less, and still more preferably 1 part by mass or more and 15 parts by mass or less.

When the content of each dichroic pigment is within the above range, the dichroic pigment in the polarizing film-forming composition exhibits sufficient solubility in a solvent. Therefore, when the present polarizing film is produced using the polarizing film-forming composition. The polarizing film can be obtained without defects. In addition, as described above, the composition for forming a polarizing film may include one or more dichroic pigments (1) and two or more dichroic pigments (2). However, the composition for forming a polarizing film also has It may contain 2 or more types of dichroic pigments (1), and may contain 3 or more types of dichroic pigments (2). When two or more dichroic pigments (1) are included, the content of the dichroic pigment (1) is the total amount of two or more dichroic pigments (1). In the case of a dichroic pigment (2), the content of the dichroic pigment (2) is a total amount of three or more dichroic pigments (2).

The dichroic pigment (2) can be obtained, for example, from Japanese Patent Laid-Open No. 58-38756, It is manufactured by a known method described in Japanese Patent No. Sho 63-301850, Japanese Patent No. Sho 58-104984, and the like.

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

1-2. Polymerizable liquid crystal compound

The polymerizable liquid crystal compound is a liquid crystal compound that can be polymerized in an aligned state, and has a polymerizable group in a molecule. The composition for forming a polarizing film containing a polymerizable liquid crystal compound is formed by polymerizing a polymerizable liquid crystal compound in an aligned state to form the present polarizing film. The polymerizable group is particularly preferably a radical polymerizable group. The so-called radical polymerizable group means a group involved in a radical polymerization reaction.

The polymerizable liquid crystal compound contained in the composition for forming a polarizing film of the present invention may be a liquid crystal phase showing a nematic phase (hereinafter, sometimes referred to as a "nematic liquid crystal phase") or a display smectic phase. The liquid crystal phase (hereinafter, sometimes referred to as a "smectic liquid crystal phase") may also be one that displays two types of liquid crystal phases, a nematic liquid crystal phase and a smectic liquid crystal phase, and preferably displays at least a smectic liquid crystal phase. Phase polymerizable smectic liquid crystal compound. The polarizing film-forming composition containing a polymerizable smectic liquid crystal compound interacts with a dichroic pigment (1) and a dichroic pigment (2) to obtain extremely good neutral hue and polarizing performance. Excellent polarizing film.

The smectic liquid crystal phase exhibited by the polymerizable smectic liquid crystal compound is preferably a high-order smectic liquid crystal phase. The so-called high-order smectic liquid crystal phases here are smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, and smectic phase. The J phase, the smectic K phase, and the smectic L phase, among which the smectic B phase, the smectic F phase, and the smectic I phase are more preferred.

If the smectic liquid crystal phase displayed by the polymerizable liquid crystal compound is such a high-order smectic liquid crystal phase, an intrinsic polarizing film with a higher degree of alignment order can be manufactured. In addition, the polarizing film made from the higher-order smectic liquid crystal phase with a higher degree of alignment in this way can obtain a Blegg peak from a hexagonal phase or a liquid crystal equivalent higher-order structure in X-ray diffraction measurement. All It is said that the Blegg peak is a peak from the periodic structure of the molecular alignment surface. With the composition for forming a polarizing film of the present invention, a polarizing film having a periodic interval of 3.0 to 5.0 Å can be obtained.

For example, it can be confirmed as follows whether the polymerizable liquid crystal compound contained in the composition for polarizing film formation shows a nematic liquid crystal phase or a smectic liquid crystal phase. An appropriate substrate is prepared, and a polarizing film-forming composition is coated on the substrate to form a coating film, and then the coating is removed by performing a heat treatment or a reduced pressure treatment under conditions where the polymerizable liquid crystal compound is not polymerized. Solvents contained in the film. Next, by using a polarizing microscope for texture observation, X-ray diffraction measurement, or differential scanning calorimetry, it is demonstrated that the coating film formed on the substrate is heated to the isotropic phase temperature and slowly cooled. Check the liquid crystal phase. In this inspection, for example, a polymerizable liquid crystal compound that displays a nematic liquid crystal phase by cooling and a smectic liquid crystal phase by further cooling is particularly preferred. In the nematic liquid crystal phase and the smectic liquid crystal phase, for example, it can be confirmed that the polymerizable liquid crystal compound and the dichroic dye are not phase-separated by observing the surface with various microscopes or measuring the scattering with a haze meter.

Specific examples of those which are preferably used as the polymerizable liquid crystal compound in the composition for forming a polarizing film are listed below.

As a preferable polymerizable liquid crystal composition, the compound represented by Formula (4) (henceforth a "compound (4)" may be mentioned) is mentioned, for example.

U ¹ -V ¹ -W ¹ -X ¹ -Y ¹ -X ² -Y ² -X ³ -W ² -V ² -U ² (4)

[In the formula (4), X ¹ , X ² and X ³ independently of each other represent a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. Among them, at least one of X ¹ , X ² and X ³ is a 1,4-phenylene group which may have a substituent. -CH _2- , which constitutes cyclohexane-1,4-diyl which may have a substituent, may be substituted with -O-, -S-, or -NR-. R is an alkyl or phenyl group having 1 to 6 carbon atoms.

Y ¹ and Y ² independently represent -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 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

U ¹ represents a hydrogen atom or a polymerizable group.

U ² represents a polymerizable group.

W ¹ and W ² independently represent a single bond, -O-, -S-, -COO-, or -OCOO-.

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

In the compound (4), at least two of X ¹ , X ² and X ³ are preferably a 1,4-phenylene group which may have a substituent.

The 1,4-phenylene group which may have a substituent is preferably unsubstituted. Cyclohexane-1,4-diyl which may have a substituent is preferably transcyclohexane-1,4-diyl which may have a substituent, and transcyclohexane-1,4 which may have a substituent. -Diyl is more preferably unsubstituted.

Examples of the optionally substituted 1,4-phenylene group or cyclohexane-1,4-diyl group which may have a substituent include carbon numbers such as methyl, ethyl, and butyl. 1 to 4 alkyl groups; cyano groups; halogen atoms and the like.

Y ^{1 of the} 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 is preferably a polymerizable group. U ¹ and U ^{2 are} preferably both polymerizable groups, and more preferably both are photopolymerizable groups. The photopolymerizable group refers to a group that can participate in a polymerization reaction by a living radical or an acid generated from a photopolymerization initiator described below. The polymerizable liquid crystal compound having a photopolymerizable group is advantageous in that it can be polymerized at a lower temperature.

In the compound (4), the polymerizable groups of U ¹ and U ² may be different from each other, and preferably the same kinds of groups. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, a propenyloxy group, a methacryloxy group, an ethylene oxide group, Oxetanyl and the like. Among them, acryloxy, methacryloxy, ethyleneoxy, ethylene oxide, and oxetanyl are preferred, and acryloxy is more preferred.

Examples of the alkanediyl group having 1 to 20 carbon atoms and the alkanediyl group having 1 to 20 carbon atoms which may have a substituent represented by V ¹ and V ² include methylene, ethylidene, and propane-1, 3-diyl, butane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1, 7-diyl, octane-1,8-diyl, decane-1,10-diyl, tetradecane-1,14-diyl and eicosane-1,20-diyl, etc. 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 optionally substituted alkyldiyl group having 1 to 20 carbon atoms which may have a substituent include a cyano group and a halogen atom. The alkyldiyl group is preferably unsubstituted, more preferably unsubstituted and straight Chained alkanediyl.

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

Examples of the compound (4) include compounds represented by the formulae (4-1) to (4-43). In the case where a specific example of such a compound (4) has cyclohexane-1,4-diyl, such cyclohexane-1,4-diyl is preferably a trans isomer.

The polymerizable liquid crystal compound can be used alone or as a mixture of two or more kinds in a composition for forming a polarizing film. When two or more kinds are mixed, at least one kind is preferably the compound (4). When mixing two polymerizable liquid crystal compounds, the mixing ratio is usually 1:99 to 50:50, which is It is preferably 5: 95 ~ 50: 50, and more preferably 10: 90 ~ 50: 50.

Among the exemplified compounds (4), the formula (4-5), the formula (4-6), the formula (4-7), the formula (4-8), the formula (4-9), and the formula (4) are preferred. -10), formula (4-11), formula (4-12), formula (4-13), formula (4-14), formula (4-15), formula (4-22), formula (4- 24) Compounds represented by formula (4-25), formula (4-26), formula (4-27), formula (4-28) and formula (4-29). By interacting with other polymerizable liquid crystal compounds, these compounds can be easily polymerized under a temperature condition lower than the crystal phase transition temperature, that is, a state in which the liquid crystal state of the high-order smectic phase is sufficiently maintained. Specifically, these compounds can be polymerized under a temperature condition of 70 ° C. or lower, preferably 60 ° C. or lower, while maintaining a liquid crystal state of a high-order smectic phase sufficiently.

The content ratio of the polymerizable liquid crystal compound in the composition for polarizing film formation is preferably 50 to 99.9% by mass, and more preferably 80 to 99.9% by mass relative to the solid content of the composition for polarizing film formation. When the content ratio of the polymerizable liquid crystal compound is within the above-mentioned range, the orientation of the polymerizable liquid crystal compound tends to be improved, so it is preferable. Here, the solid content means a total amount of components obtained by removing volatile components such as a solvent from the composition for forming a polarizing film.

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

1-3. Solvent

The composition for forming a polarizing film preferably contains a solvent. The solvent is preferably a solvent capable of completely dissolving the polymerizable liquid crystal compound and the dichroic dye. Furthermore, a solvent which is inert to the polymerization reaction of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film is preferred.

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; ethyl acetate, butyl acetate, and ethylene glycol Ester solvents such as alcohol methyl ether acetate, γ-butyrolactone or propylene glycol methyl ether acetate and ethyl lactate; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl Isotin Ketone solvents such as ketones; 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; chloroform and chlorine Chlorine-containing solvents such as benzene; etc. These solvents may be used alone or in combination.

The content of the solvent is preferably 50 to 98% by mass based on the total amount of the composition for forming a polarizing film. In other words, the solid content in the polarizing film-forming composition is preferably 2 to 50% by mass. If the solid content is 2% by mass or more, the thin polarizing film, which is an object of the present invention, tends to be easily obtained, and therefore, it is preferable. In addition, if the solid content is 50% by mass or less, the viscosity of the composition for forming a polarizing film is reduced, so that the thickness of the polarizing film becomes substantially uniform. As a result, there is a tendency that unevenness of the polarizing film is less likely to occur, so good. In addition, such a solid component 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 assistant

The composition for forming a polarizing film preferably contains a polymerization initiator. The polymerization initiator is a compound capable of starting a polymerization reaction of a polymerizable liquid crystal compound. In terms of the fact that the polymerization reaction can be started at a low temperature, the polymerization initiator is preferably a photopolymerization initiator. Specifically, a compound that generates a living radical or an acid by the action of light can be used as a photopolymerization initiator. Among the photopolymerization initiators, those that generate living radicals by the action of light are more preferred.

Examples of the polymerization initiator include a benzoin compound, a diphenyl ketone compound, a phenalkyl ketone compound, a fluorenyl phosphine oxide compound, and tris Compounds, phosphonium salts and phosphonium salts.

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

Examples of the diphenyl ketone compound include diphenyl ketone and orthobenzophenone Methyl ester, 4-phenyldiphenyl ketone, 4-benzylidene-4'-methyldiphenyl sulfide, 3,3 ', 4,4'-tetrakis (third butylperoxycarbonyl) Diphenyl ketone and 2,4,6-trimethyldiphenyl ketone.

Examples of the acetophenone compound include diethoxyacetophenone, 2-methyl-2- Phenyl-1- (4-methylthienyl) propane-1-one, 2-benzyl-2-dimethylamino-1- (4- (Phenylphenyl) butane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1,2-diphenyl-2,2-dimethoxyethane- 1-ketone, 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl] propane-1-one, 1-hydroxycyclohexylphenyl ketone, and 2-hydroxy-2- An oligomer of methyl-1- [4- (1-methylvinyl) phenyl] propane-1-one and the like.

Examples of the fluorenylphosphine oxide compound include 2,4,6-trimethylbenzylfluorenyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzylfluorenyl) phenylphosphine oxide.

As three Examples of the compound include 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3,5-tris , 2,4-bis (trichloromethyl) -6- (4-methoxynaphthyl) -1,3,5-tri , 2,4-bis (trichloromethyl) -6- (4-methoxystyryl) -1,3,5-tris , 2,4-bis (trichloromethyl) -6- [2- (5-methylfuran-2-yl) vinyl] -1,3,5-tris , 2,4-bis (trichloromethyl) -6- [2- (furan-2-yl) vinyl] -1,3,5-tris , 2,4-bis (trichloromethyl) -6- [2- (4-diethylamino-2-methylphenyl) vinyl] -1,3,5-tris And 2,4-bis (trichloromethyl) -6- [2- (3,4-dimethoxyphenyl) vinyl] -1,3,5-tris Wait.

Commercially available polymerization initiators can also be used. Examples of commercially available polymerization initiators include "Irgacure907", "Irgacure184", "Irgacure651", "Irgacure819", "Irgacure250", "Irgacure369" (Ciba-Japan Co., Ltd.); "Seikuol BZ", " "Seikuol Z", "Seikuol BEE" (Seiko Chemical Co., Ltd.); "kayacure BP100" (Nippon Kayaku Co., Ltd.); "kayacure UVI-6992" (manufactured by Dow); "Adeka Optomer SP-152", " "Adeka Optomer SP-170" (ADEKA Co., Ltd.); "TAZ-A", "TAZ-PP" (Nihon SiberHegner); and "TAZ-104" (Sanwa Chemical).

When the composition for forming a polarizing film contains a polymerization initiator, its content may be It is appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film. Generally, the content of the polymerization initiator relative to 100 parts by mass of the polymerizable liquid crystal compound is 0.1 to 30 parts by mass. Preferably it is 0.5-10 mass parts, More preferably, it is 0.5-8 mass parts. If the content of the polymerizable initiator is within this range, polymerization can be performed without disturbing the orientation of the polymerizable liquid crystal compound, so it is preferable.

1-4-2. Photosensitizer

When the composition for polarizing film formation contains a photopolymerization initiator, the composition for polarizing film formation may contain a photosensitizer. Examples of the photosensitizer include: Ketones and 9-oxysulfur Wait Ketone compounds (e.g. 2,4-diethyl 9-oxosulfur , 2-isopropyl 9-oxysulfur Etc.); anthracene and anthracene compounds containing alkoxy-containing anthracene (such as dibutoxyanthracene, etc.); And rubrene.

When the composition for polarizing film formation contains a photopolymerization initiator and a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the composition for polarizing film formation is further promoted. The content of such a photosensitizer can be appropriately adjusted according to the type and amount of the photopolymerization initiator and the polymerizable liquid crystal compound used in general, and it is generally 0.1 to 30 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound, It is preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass.

1-4-3. Polymerization inhibitor

In order to stabilize the polymerization reaction of a polymerizable liquid crystal compound, the composition for polarizing film formation may contain a polymerization inhibitor. The polymerization inhibitor can control the progress of the polymerization reaction of the polymerizable liquid crystal compound.

Examples of the polymerization inhibitor include hydroquinone, alkoxy-containing hydroquinone, alkoxy-containing catechol (for example, butylcatechol, etc.), catechol, 2 , 2,6,6-tetramethyl-1-piperidinyloxy radicals and other free radical supplements; thiophenols; β-naphthylamines and β-naphthols.

When a polymerization inhibitor is contained in the composition for polarizing film formation, the content It can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound used, the content of the photosensitizer, etc., and it is usually 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. , More preferably 0.5 to 8 parts by mass.

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

1-4-4. Leveling agent

The composition for forming a polarizing film preferably contains a leveling agent. The leveling agent has a function of adjusting the fluidity of the composition for forming a polarizing film to make the coating film obtained by applying the composition for forming a polarizing film flatter, and examples thereof include a surfactant. Examples of a preferable leveling agent include a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component.

Examples of the leveling agent containing a polyacrylate compound as a main component include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", and "BYK- 358N "," BYK-361N "," BYK-380 "," BYK-381 ", and" BYK-392 "[BYK Chemie].

As a leveling agent containing a compound containing a fluorine atom as a main component, there may be listed: "MEGAFAC R-08", same as "R-30", same as "R-90", same as "F-410", and "F- 411 ", same as" F-443 ", same as" F-445 ", same as" F-470 ", same as" F-471 ", same as" F-477 ", same as" F-479 ", same as" F-482 " "And" F-483 "[DIC Corporation];" Surflon S-381 "," S-382 "," S-383 "," S-393 "," SC-101 ", Same as "SC-105", "KH-40" and "SA-100" [AGC Seimi Chemical Co., Ltd.]; "E1830", "E5844" [Daikin Fine Chemical Research Institute Co., Ltd.]; "Eftop EF301", Same as "EF303", "EF351" and "EF352" [Mitsubishi Materials Electronic Chemicals Co., Ltd.], etc.

When a leveling agent is contained in the composition for forming a polarizing film, its 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 based on 100 parts by mass of the polymerizable liquid crystal compound. The following. If the content of the leveling agent is within the above range, it is preferable because the polymerizable liquid crystal compound can be easily horizontally aligned and the obtained polarizing film becomes smoother. When the content of the leveling agent with respect to the polymerizable liquid crystal compound exceeds the above range, the obtained polarizing film tends to be uneven. The composition for forming a polarizing film may contain two or more leveling agents.

2. Formation method of the polarizing film

Next, a method for forming the present polarizing film from the composition for forming a polarizing film will be described. This method forms the polarizing film by applying a composition for forming a polarizing film on a substrate, preferably a transparent substrate.

2-1. Transparent substrate

The transparent substrate is a substrate having transparency to the extent that it can transmit light, especially visible light. The so-called transparency refers to the characteristic that the transmittance of light in a wavelength range of 380 to 780 nm is more than 80%. Specifically, examples of the transparent substrate include a glass substrate and a plastic substrate, and a plastic substrate is preferred. As the plastic constituting the plastic substrate, for example, polyethylene, polypropylene, polyester Polyolefins such as olefin polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylates; polyacrylates; cellulose triacetate, cellulose diacetate, and propionic acid Polyester such as cellulose; Polyethylene naphthalate; Polycarbonate; Polyfluorene; Polyether fluorene; Polyether ketone; Polyphenylene sulfide and polyphenylene ether. Among them, cellulose ester, cyclic olefin-based resin, polyethylene terephthalate, or polymethacrylate is particularly preferable in terms of being easily available from the market or having excellent transparency. When the polarizing film is manufactured using such a transparent substrate, it can be easily handled without damage such as cracking when the transparent substrate is transported or stored. Support substrate, etc. In the following description, when a circularly polarizing plate is manufactured from the polarizing film, a retardation may be imparted to a plastic substrate. In this case, the retardation may be imparted to the plastic substrate by an extension process or the like.

When providing retardation to a plastic substrate, a plastic substrate containing a cellulose ester or a cyclic olefin resin is preferred in terms of easy control of the retardation value.

Cellulose ester is obtained by esterifying at least a part of the hydroxyl groups contained in cellulose. Cellulose ester films containing such cellulose esters are readily available on the market. Examples of commercially available cellulose triacetate films include: "Fujitac Film" (Fuji Photo Film Co., Ltd.); "KC8UX2M", "KC8UY", and "KC4UY" (Konica Minolta Opto Co., Ltd.). Such a commercially available cellulose triacetate film can be used as a transparent substrate directly or optionally after imparting retardation. The surface of the prepared transparent substrate can be used as a transparent substrate after being subjected to a surface treatment such as anti-glare treatment, hard coating treatment, antistatic treatment, or anti-reflection treatment.

As described above, retardation is provided to the plastic substrate by a method such as stretching the plastic substrate. Plastic substrates containing thermoplastic resins can be stretched. In terms of easy control of retardation, plastic substrates containing cyclic olefin resins are more preferred. The cyclic olefin resin includes, for example, Polyene In the case of a polymer or copolymer of a cyclic olefin such as an olefinic monomer, the cyclic olefin-based resin may partially contain a ring-opening portion. It is also possible to hydrogenate a cyclic olefin-based resin including a ring-opening portion. The cyclic olefin resin may be, for example, a cyclic olefin and a chain olefin, or a vinylated aromatic compound (styrene, etc.) in terms of not significantly impairing transparency or not significantly increasing hygroscopicity. ) And the like. The cyclic olefin-based resin may have a polar group introduced into the molecule.

When the cyclic olefin resin is a copolymer of a cyclic olefin and a chain olefin or an aromatic compound having a vinyl group, the chain olefin is ethylene, propylene, or the like, and the vinylated aromatic compound is styrene, α-methylstyrene and alkyl-substituted styrene. In such a copolymer, the content ratio of the structural unit derived from a cyclic olefin is 50 mol% or less with respect to the total structural unit of the cyclic olefin resin, for example, about 15 to 50 mol%. When the cyclic olefin resin is a terpolymer obtained from a cyclic olefin, a chain olefin, and an ethylenized aromatic compound, for example, the content ratio of the structural unit derived from the chain olefin relative to the cyclic olefin system The total structural unit of the resin is about 5 to 80 mol%, 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 the advantage that the amount of expensive cyclic olefins can be relatively reduced when the cyclic olefin-based resin is produced.

Cyclic olefin-based resins are easily available from the market. Examples of commercially available cyclic olefin resins include: "Topas" [Ticona Co., Ltd.]; "Arton" [JSR Corporation]; "ZEONOR" and "ZEONEX" [Japan Zeon Corporation]; "APEL [Mitsui Chemical Co., Ltd.] and so on. For example, this cyclic olefin resin can be formed into a film (cyclic olefin resin film) by a known film forming method such as a solvent casting method or a melt extrusion method. In addition, a cyclic olefin resin film that is commercially available in the form of a film may be used. Examples of such commercially available cyclic olefin-based resin films include "S-SINA" and "SCA40" [Sekisui Chemical Industry Co., Ltd.]; "Zeonor Film" [Optes Corporation]; "Arton Film" [JSR Corporation] and others.

Next, a method for imparting retardation to a plastic substrate will be described. The plastic substrate can be provided with retardation by a known extension method. For example, a roll (rolled body) having a plastic base material wound on a roll is prepared, the plastic base material is continuously rolled out from such a rolled body, and the rolled plastic base material is transferred to a heating furnace. The setting temperature of the heating furnace is set to the vicinity of the glass transition temperature of the plastic substrate (° C) ~ [glass transition temperature +100] (° C), and preferably the vicinity of the glass transition temperature (° C) to [glass transition temperature] +50] (° C). In this heating furnace, when extending in the direction of travel of the plastic substrate or a direction orthogonal to the direction of travel, the conveying direction or tension is adjusted and an inclination is given at an arbitrary angle to perform a uniaxial or biaxial heat stretching treatment. The stretching magnification 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. The method of extending in the oblique direction is not particularly limited as long as it can continuously incline the desired angle in the alignment axial direction, and a known extension method can be adopted. this Examples of such extension methods include the methods described in Japanese Patent Laid-Open No. Sho 50-83482 or Japanese Patent Laid-Open No. 2-113920.

The thickness of the transparent substrate is preferably thin in terms of weight to the extent that practical operations can be performed and sufficient transparency can be ensured, but if it is too thin, the strength tends to decrease and the workability tends to be poor. A suitable thickness of the glass substrate is, for example, about 100 to 3000 μm, and preferably about 100 to 1,000 μm. A suitable thickness of the plastic substrate is, for example, about 5 to 300 μm, and preferably about 20 to 200 μm. When the present polarizing film is used as a circular polarizing plate described below, particularly when it is used as a circular polarizing plate for mobile device applications, the thickness of the transparent substrate is preferably about 20 to 100 μm. In addition, in the case where retardation is given to the film by stretching, the thickness after stretching depends on the thickness before stretching or the stretching magnification.

2-2. Alignment film

It is preferable that an alignment film is formed on a substrate used in the production of the polarizing film. In this case, the composition for forming a polarizing film is applied on the alignment film. Therefore, the alignment film preferably has a solvent resistance to such an extent that it does not dissolve due to application of the composition for forming a polarizing film. Moreover, it is preferable to have heat resistance in the heat processing for removal of a solvent or alignment of a liquid crystal. Such an alignment film may be formed of an alignment polymer.

Examples of the alignment polymer include polyamines or gelatins having a fluorene bond in the molecule, polyfluorene acids having a fluorene imine bond in the molecule, and polyhydrolyzates thereof, Polyvinyl alcohol, alkyl modified polyvinyl alcohol, polypropylene amidamine, poly Polymers such as azole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid or polyacrylates. Among these, polyvinyl alcohol is preferred. The alignment polymers forming the alignment film may be used alone or as a mixture of two or more.

An alignment film can be formed on the substrate by forming the above-mentioned alignment polymer into an alignment polymer composition (a solution containing the alignment polymer) dissolved in a solvent and coating the substrate on the substrate. Examples of the solvent include: water; alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, methyl cyrus, butyl cyrus, and propylene glycol monomethyl ether; ethyl acetate Ester solvents such as esters, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; acetone, methyl ethyl ketone, cyclopentanone, and cyclohexanone , Ketone solvents such as methylpentyl 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; tetrahydrofuran and dimethyl Ether solvents such as oxyethane; chlorine-substituted hydrocarbon solvents such as chloroform and chlorobenzene; etc. These organic solvents may be used alone or in combination.

Moreover, as an alignment polymer composition for forming an alignment film, a commercially available alignment film material can also be used as it is. Examples of commercially available alignment film materials include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optomer (registered trademark, manufactured by JSR Corporation).

Examples of a method for forming an alignment film on a substrate include a method of applying the above-mentioned alignment polymer composition or a commercially available alignment film material to a substrate, and then performing annealing. The thickness of the alignment film obtained in this way is usually in the range of 10 nm to 10000 nm, and preferably in the range of 10 nm to 1000 nm.

It is preferable to perform rubbing (friction method) as necessary to give an alignment restricting force to the alignment film. By providing an alignment restricting force, the polymerizable liquid crystal compound can be aligned in a desired direction.

As a method for imparting an alignment restricting force by a rubbing method, for example, a method is provided in which a rubbing roller having a rubbing cloth wound thereon and rotating is prepared, and a laminated body on which a coating film for forming an alignment film is formed on a substrate is loaded. The coating film for forming an alignment film is brought into contact with the rotating friction roller by being transported on the mounting table to the rotating friction roller.

It is also possible to use a so-called photo-alignment film. The photo-alignment film refers to coating a substrate with a composition (hereinafter, sometimes referred to as a "photo-alignment layer-forming composition") containing a polymer or a monomer having a photoreactive group and a solvent. An alignment film having an alignment restriction force is irradiated with polarized light (preferably polarized UV (Ultraviolet)). The photoreactive group refers to a group that generates liquid crystal alignment energy by irradiating light (light irradiation). in particular, It is a photoreaction that is the origin of the alignment energy of liquid crystals such as the alignment induction or isomerization reaction of molecules generated by irradiation with light, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction. Among the photoreactive groups, those having excellent alignment properties and maintaining a smectic liquid crystal state at the time of formation of the polarizing film are preferably those that cause a dimerization reaction or a photocrosslinking reaction. The photoreactive group capable of generating the above reaction is preferably one having an unsaturated bond, especially a double bond, and particularly preferably one selected from a carbon-carbon double bond (C = C bond) and a carbon-nitrogen double bond (C = N Bond), a nitrogen-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 polyalkenyl group, a fluorenyl group, an oxazolyl group, an oxazolyl group, a chalcone group, and a cinnamyl group. Examples of the photoreactive group having a C = N bond include groups having a structure such as an aromatic Schiff base and an aromatic fluorene. Examples of the photoreactive group having an N = N bond include an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a bisazo group, a methylamino group, and the like, or an oxazobenzene group Basic structure. Examples of the photoreactive group having a C = O bond include a diphenyl ketone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have substituents such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a haloalkyl group.

Among them, a photoreactive group capable of generating a photodimerization reaction is preferred, and the cinnamyl and chalcone groups have a relatively small amount of polarized light irradiation due to light alignment, and are easily obtained with excellent thermal stability or stability over time. A photo-alignment film is preferred. In this regard, the polymer having a photoreactive group is particularly preferably one in which a terminal portion of a side chain of the polymer has a cinnamyl group such as a cinnamic acid structure.

The solvent of the composition for forming a photo-alignment layer is preferably one which dissolves a polymer and a monomer having a photoreactive group. Examples of the solvent include the above-mentioned solvents for use in an alignment polymer composition.

The concentration of the polymer or monomer having a photoreactive group with respect to the composition for forming a photoalignment layer can be appropriately adjusted according to the type of the polymer or monomer having a photoreactive group or the thickness of the photoalignment film to be manufactured. , Expressed as the concentration of solid components, preferably set to It is preferably 0.2 mass% less, and more preferably 0.3 to 10 mass%. In addition, the composition for forming an alignment layer may contain a polymer material such as polyvinyl alcohol or polyimide and a photosensitizer within a range that does not significantly impair the characteristics of the photo-alignment film.

As a method for applying the alignment polymer composition or the composition for forming a photo-alignment layer on a substrate, a spin coating method, an extrusion method, a gravure coating method, a die coating method, or a rod coating method can be adopted. A well-known method such as a coating method such as an applicator method or a printing method such as a flexographic method. In addition, when the present polarizing film is manufactured by a continuous manufacturing method in the form of a roll to roll method described below, the coating method generally uses printing such as a gravure coating method, a die coating method, or a flexographic method. law.

Furthermore, if masking is performed during rubbing or polarized light irradiation, a plurality of regions (patterns) with different alignment directions may be formed.

2-3. Manufacturing method of the present polarizing film

A polarizing film-forming composition is coated on the substrate or the alignment film formed on the substrate to obtain a coating film. Examples of the method for applying the composition for forming a polarizing film include the same methods as those exemplified as the method for applying an alignment polymer or a composition for forming a photoreactive layer on a substrate.

Then, the solvent is removed by drying under the condition that the polymerizable liquid crystal compound contained in the coating film is not polymerized, thereby forming a dry film. Examples of the drying method include a natural drying method, a ventilation drying method, a heating drying method, and a reduced-pressure drying method.

Next, as a preferred form, the liquid crystal state of the polymerizable liquid crystal composition contained in the dry film is temporarily set to a nematic liquid crystal, and then the nematic liquid crystal phase is transferred to a smectic liquid crystal phase.

In order to form a smectic liquid crystal phase through the nematic liquid crystal phase in this manner, for example, a method may be adopted in which the polymerizable liquid crystal compound contained in the dry film is heated to a temperature above the temperature of the nematic liquid crystal phase, and then cooled to the polymerization. The liquid crystal compound displays the temperature of the smectic liquid crystal phase.

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

Next, the polymerization process of a polymerizable liquid crystal compound is demonstrated. Here, the method will be described in detail. After the composition for forming a polarizing film contains a photopolymerization initiator, and the liquid crystal state of the polymerizable liquid crystal compound in the dried film is set to a smectic liquid crystal phase, this is maintained. The polymerizable liquid crystal compound is photopolymerized in a liquid crystal state of the smectic liquid crystal phase.

In photopolymerization, the light to be irradiated on the dry film may be based on the type of the photopolymerization initiator contained in the dry film or the type of the polymerizable liquid crystal compound (especially the polymerizable liquid crystal compound has The type of the polymerizable group) and its amount are suitably performed by light or an active electron beam selected from the group consisting of visible light, ultraviolet light, and laser light. Among these, ultraviolet light is preferable in terms of the ease of controlling the progress of the polymerization reaction, or the point that a wide range of users in the field can be used as a device for photopolymerization. Therefore, it is preferable to select the type of the polymerizable liquid crystal compound or the photopolymerization initiator contained in the polarizing film-forming composition so that photopolymerization can be performed by ultraviolet light. In addition, during the polymerization, in addition to the ultraviolet light irradiation, the polymerization temperature may be controlled by cooling the dried film by an appropriate cooling method. Adopting such a cooling method also has the advantage that if the polymerizable liquid crystal compound can be polymerized at a lower temperature, the polarizing film can be appropriately formed even if the substrate is relatively low in heat resistance. Furthermore, the patterned polarizing film can also be obtained by masking or developing during photopolymerization.

By performing photopolymerization as described above, the polymerizable liquid crystal compound is polymerized while maintaining the nematic liquid crystal phase, the smectic liquid crystal phase, and preferably the higher-order smectic liquid crystal phase as exemplified, thereby forming the present polarizing film. . Polymerizable liquid crystal compound in a smectic liquid crystal phase This polarizing film obtained by polymerizing in a state has polarizing properties compared with the previous host-guest polarizing film, that is, a polarizing film obtained by polymerizing a polymerizable liquid crystal compound and the like while maintaining a liquid crystal state of a nematic liquid crystal phase. Higher advantages. Furthermore, it has the advantage that it is excellent in intensity compared with the case where only the liquid dichroic dye is applied.

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

As described above, the polarizing film thus formed is particularly preferably one capable of obtaining a Bragg peak in an X-ray diffraction measurement. Examples of such a polarizing film capable of obtaining a Bragg wave include a polarizing film showing diffraction peaks derived from a hexagonal phase or a liquid crystal phase.

Furthermore, the polarizing film produced in this way is excellent in neutral hue. Here, the so-called polarizing film with excellent neutral hue is a color coordinate a ^* value and b ^* value in the L ^* a ^* b ^* (Lab) color system which satisfies the following formulas (1F) and (2F) Related person. In addition, these color coordinates a ^* value and b ^* value can be calculated | required by the measuring method demonstrated in the Example of this application, for example.

-3 ≦ chromaticity a ^* ≦ 3 (1F)

-3 ≦ chroma b ^* ≦ 3 (2F)

Each of the color coordinates a ^* value and b ^* value referred to herein is also referred to as "chroma a ^* " and "chroma b ^* ". The closer these a ^* and b ^* are to 0 (zero), the more it can be judged that the polarizing film exhibits a neutral hue. In a display device having such a polarizing film, a good white display without coloring can be obtained.

In addition, in the hue of the polarizing film, two polarizing films are overlapped so that the absorption axes are orthogonal to each other, and the hue at this time is obtained in the same manner as described above to calculate "orthogonal a ^* " and "orthogonal b" ^* ", It is further preferred that each of such orthogonal a ^* and orthogonal b ^* satisfies the relationship of the following formula (1F ') and (2F'). In a display device with a polarizing film, the orthogonal a ^* and orthogonal b ^* are indicators indicating whether the hue of the black display is neutral. The closer the orthogonal a ^* and the orthogonal b ^* are to 0 (zero), the better the black display without coloring can be obtained.

-3 ≦ orthogonal a ^* ≦ 3 (1F ')

-3 ≦ orthogonal b ^* ≦ 3 (2F ')

3. Continuous manufacturing method of the polarizing film

In the foregoing, the outline of the manufacturing method of the polarizing film has been described, but when commercializing the polarizing film, a method capable of continuously manufacturing the polarizing film is required. This continuous manufacturing method is achieved in a roll-to-roll format, and is sometimes referred to as "this manufacturing method". In addition, in this manufacturing method, it demonstrates centering on the case where a base material is a transparent base material. In the case where the substrate is a transparent substrate, the finally obtained person is a polarizing element (hereinafter, sometimes referred to as “the present polarizing element”) having a transparent substrate and the polarizing film.

The manufacturing method includes, for example, a step of preparing a first roll with a transparent substrate wound on a first roll core, a step of continuously sending the transparent substrate from the first roll, and a continuous formation on the transparent substrate. A step of aligning a film; a step of continuously applying a composition for forming a polarizing film on the alignment layer; and drying the applied composition for forming a polarizing film because the polymerizable liquid crystal compound is not polymerized under the condition that the polymerizable liquid crystal compound is not polymerized The step of continuously forming a dry film; after setting the polymerizable liquid crystal compound contained in the dry film to a nematic liquid crystal phase, preferably a smectic liquid crystal phase, maintaining the state of the smectic liquid crystal phase A step of polymerizing the polymerizable liquid crystal compound to continuously obtain a polarizing film to form a polarizing element; and a step of winding the continuously obtained polarizing element onto a second roll core to obtain a second roll. Here, referring to FIG. 1, the present manufacturing method will be described with respect to a case where a photo-alignment film is particularly used as the alignment film.

The first roll 210 having a transparent base material wound around the first roll core 210A is easily available from the market, for example. As such a transparent substrate that can be obtained from the market in the form of a roll, examples of the transparent substrate include cellulose ester, cyclic olefin resin, and polyterephthalic acid. Films of ethylene formate, polycarbonate or polymethacrylate. Moreover, when this polarizing film is used as a circular polarizing plate, a transparent substrate previously provided with retardation can be easily obtained from the market, and examples thereof include a retardation film containing cellulose ester or a cyclic olefin resin. .

Then, the transparent base material is unwound from the first roll 210. The method of rolling out the transparent substrate is performed by providing an appropriate rotation mechanism to the core 210A of the first roll 210 and rotating the first roll 210 by the rotation mechanism. In addition, an appropriate auxiliary roller 300 may be provided in a direction in which the transparent substrate is conveyed from the first roll 210, and the transparent substrate may be taken up by a rotation mechanism of the auxiliary roller 300. Furthermore, the first roll core 210A and the auxiliary roll 300 are both provided with a rotating mechanism, and a moderate tension is applied to the transparent substrate while the transparent substrate is rolled out.

When the transparent substrate rolled out from the first roll 210 passes through the coating device 211A, the coating device 211A is used to apply a composition for forming a photo-alignment layer on the surface. As described above, in order to continuously apply the composition for forming a photo-alignment layer, a printing method such as a gravure coating method, a die coating method, or a flexographic method is performed by the coating device 211A.

The transparent substrate that has passed through the coating device 211A is transported to a drying furnace 212A and heated by the drying furnace 212A, so that a first dry film is continuously formed on the transparent substrate. As the drying furnace 212A, for example, a hot-air drying furnace can be used. The set temperature of the drying furnace 212A can be determined according to the type of the solvent contained in the photo-alignment layer-forming composition applied by the coating device 211A, and the like. In addition, the drying furnace 212A may be a drying furnace that is divided into a plurality of regions and has a different set temperature for each of the distinguished plurality of regions, or a plurality of drying furnaces that are arranged in series and each of the drying furnaces Drying ovens with different set temperatures.

The first dry film formed continuously by passing through the heating furnace 212A, and then the polarized UV irradiation device 213A irradiates the surface of the first dry film side or the surface of the transparent substrate side with polarized UV, so that the first dry film The film forms a (light) alignment film. At this time, the angle formed by the transport direction D1 of the transparent substrate and the alignment direction D2 of the formed optical alignment film may also be crossed. cross. FIG. 2 is a schematic diagram showing a relationship between an alignment direction D2 of a light alignment film formed after polarized UV irradiation and a transport direction D1 of a transparent substrate. That is, FIG. 2 shows that when the transport direction D1 of the transparent substrate and the alignment direction D2 of the photo-alignment film are observed on the surface of the first laminated body after passing through the polarized UV irradiation device 213A, the angle formed by them is approximately 45 °.

The transparent substrate (first multilayer body) in which the photo-alignment film is continuously formed in this manner is then applied to the photo-alignment film by the coating device 211B, and then passed 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, thereby forming a second dry film.

With regard to the transparent substrate that has passed through the above-mentioned drying furnace 212B, the solvent contained in the polarizing film-forming composition is sufficiently removed, and the polymerizable liquid crystal compound in the second drying film maintains the nematic liquid crystal phase, and is preferably The smectic liquid crystal phase is transported to the light irradiation device 213B in a liquid crystal state. The polymerizable liquid crystal compound is photo-polymerized while maintaining the liquid crystal state by the light irradiation device 213B, and the polarizing film is continuously formed on the alignment film to obtain the polarizing element.

The polarizing film thus continuously formed is wound around the second roll core 220A in the form of a laminated body including a transparent substrate and an alignment film to obtain the form of the second roll 220. When the formed polarizing film is wound to obtain a second roll, co-rolling using an appropriate spacer may be performed.

In this way, the transparent substrate is sequentially passed through the first roll / coating device 211A / drying furnace 212A / polarized UV irradiation device 213A / coating device 211B / drying furnace 212B / light irradiation device 213B on the transparent substrate The present polarizing film is continuously formed on the light alignment film, thereby producing the present polarizing element.

In addition, although the present manufacturing method shown in FIG. 1 shows a continuous manufacturing method from the transparent substrate to the polarizing film, the present polarizing element can also be manufactured, for example, by passing the transparent substrate in order 1st roll / coating device 211A / drying furnace 212A / polarization The first laminated body continuously formed by the UV irradiating device 213A is wound on a roll core to manufacture the first laminated body in the form of a roll, and the first laminated body is rolled out from the roll, and the rolled first The laminated body passes through the coating device 211B / drying furnace 212B / light irradiation device 213B in this order.

The polarizing element obtained by this manufacturing method is a film-like and elongated one. When this polarizing film is used in the following liquid crystal display devices and the like, the polarizing film is cut and used in such a manner that it becomes a desired size according to the size of the liquid crystal display device and the like.

In the above, although the configuration of the polarizing element and the method for manufacturing the polarizing element have been described with the focus on the form of the laminated body of the transparent substrate / light-aligning film / the polarizing film, the light-aligning film can also be peeled off Or a transparent substrate to obtain the polarizing film in the form of a single layer. In addition, it is also possible to adopt a form in which a layer or a film other than the transparent substrate, the light alignment film, and the polarizing film is laminated on the polarizing element. As such layers and films, as described above, this polarizing film may further have a retardation film, and may further have an anti-reflection layer or a brightness enhancement film.

In addition, 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 prepared by using the transparent substrate itself as a retardation film. For example, in the case of using a 1 / 4-wavelength plate with a uniaxial extension as the retardation film, by setting the irradiation direction of polarized UV to be approximately 45 ° with respect to the transport direction of the transparent substrate, it is possible to roll-to-roll Form making circular polarizer. It is preferable that the quarter-wave plate used for manufacturing the circularly polarizing plate has a characteristic that the phase difference value in the plane with respect to visible light becomes smaller as the wavelength becomes shorter.

In addition, by using a 1/2 wavelength plate as a retardation film, a linear polarizing plate roll that sets the angle between its late phase axis and the absorption axis of the polarizing film, such as by offset, can be made on the surface where the polarizing film is formed. A 1/4 wavelength plate is formed on the opposite side, and a circularly polarizing plate with a wide frequency band is formed.

4. Uses of this polarizing film

This polarizing film can be used in various display devices. The 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. Examples of the display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, and an electron emission display device (for example, a field emission display device (FED, Field Emission Display), Surface-conduction Electron-emitter Display (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection display device (e.g. grid GLV (Grating Light Valve) display device, display device with Digital Micromirror Device (DMD), and piezoelectric ceramic display. As for liquid crystal display devices, transmissive liquid crystal display devices, semi-transmissive liquid crystal display devices, reflective liquid crystal display devices, intuitive liquid crystal display devices, and projection liquid crystal display devices are included. These display devices may be display devices that display two-dimensional images, or stereo display devices that display three-dimensional images.

The polarizing film is particularly effective for a display device of an organic electroluminescence (EL) display device or an inorganic electroluminescence (EL) display device.

FIG. 3 is a schematic view showing a cross-sectional structure of a liquid crystal display device (hereinafter, sometimes referred to as “the present liquid crystal display device”) 10 using the present polarizing film. The liquid crystal layer 17 is sandwiched between two substrates 14a and 14b.

6 and 10 are schematic diagrams showing a cross-sectional structure of an EL display device (hereinafter, sometimes referred to as “the EL display device”) using the polarizing film.

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

First, the present 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 opposed to the pixel electrode 22 so as to sandwich the liquid crystal layer 17, and the black matrix 20 is disposed at a position opposed to a 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. Furthermore, a protective layer (not shown) may be provided between the color filter 15 and the transparent electrode 16.

A thin film transistor 21 and a pixel electrode 22 are arranged in an orderly manner on the liquid crystal layer 17 side of the substrate 14b. The pixel electrode 22 is disposed in a phase opposite to the color filter 15 so as to sandwich the liquid crystal layer 17. Opposite position. An interlayer insulating film 18 having a connection hole (not shown) is disposed between the thin film transistor 21 and the pixel electrode 22.

As the substrate 14a and the substrate 14b, a glass substrate and a plastic substrate can be used. Such a glass substrate or a plastic substrate may be made of the same material as that exemplified as the transparent substrate used in the production of the polarizing film. The transparent substrate 1 of the polarizing film may also serve as the substrate 14a and the substrate 14b. When a step of heating to a high temperature is necessary when manufacturing the color filter 15 or the thin film transistor 21 formed on the substrate, a glass substrate or a quartz substrate is preferred.

The thin film transistor may be the most suitable depending on the material of the substrate 14b. Examples of the thin film transistor 21 include a high-temperature polycrystalline silicon transistor formed on a quartz substrate, a low-temperature polycrystalline silicon transistor formed on a glass substrate, and an amorphous silicon transistor formed on a glass substrate or a plastic substrate. In order to make the liquid crystal display device more compact, a driver IC (Integrated Circuit) may be formed on the substrate 14b.

A liquid crystal layer 17 is disposed between the transparent electrode 16 and the pixel electrode 22. In order to keep the distance between the substrate 14 a and the substrate 14 b constant, a spacer 23 is arranged in the liquid crystal layer 17. In addition, although FIG. 3 is illustrated with a columnar spacer, the spacer is not limited to a columnar shape, and the shape may be any shape as long as the distance between the substrate 14a and the substrate 14b can be kept fixed.

Each member is laminated in the order of the substrate 14a, the color filter 15 and the black matrix 20, the transparent electrode 16, the liquid crystal layer 17, the pixel electrode 22, the interlayer insulating film 18 and the thin film transistor 21, and the substrate 14b.

In such a substrate 14a and a substrate 14b that sandwich the liquid crystal layer 17, polarizing elements 12a and 12b are provided on the outer side of the substrate 14b. At least one of these uses the polarizing element.

Further, it is preferable that the retardation layers (such as a quarter-wave plate or an optical compensation film) 13a and 13b are laminated. In the polarizing elements 12a and 12b, by disposing the polarizing film on the polarizing element 12b, the liquid crystal display device 10 can be provided with a function of converting incident light into linearly polarized light. In addition, depending on the structure of the liquid crystal display device or the type of the liquid crystal compound contained in the liquid crystal layer 17, the retardation films 13a and 13b may not be provided, and the transparent substrate is used as the retardation film and includes In the case of a circularly polarizing plate of a polarizing film, since the retardation film can be used as a retardation layer, the retardation layers 13a and / or 13b of FIG. 3 can also be omitted. A polarizing film may be further provided on the light emitting side (outside) of the polarizing element.

Further, an anti-reflection film for preventing reflection of external light may be disposed on the outer side of the polarizing element (in the case where a polarizing film is further provided on the polarizing film, the outer side thereof).

As described above, the polarizing element 12a or 12b of the present liquid crystal display device 10 of FIG. 3 can use the present polarizing element. By providing the polarizing element as the polarizing element 12a and / or 12b, the thinning effect of the liquid crystal display device 10 can be achieved.

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

FIG. 4 is an enlarged schematic cross-sectional view of part A of FIG. 3. (A1) of FIG. 4 shows that when the present polarizing element 100 is used as the polarizing element 12a, the present polarizing film 3, the light alignment film 2 and the transparent substrate are arranged in order from the retardation layer 13a side. 1 case. Moreover, (A2) of FIG. 4 shows the case where the transparent base material 1, the photo-alignment film 2, and the polarizing film 3 are arrange | positioned in order from the retardation layer 13a side.

FIG. 5 is an enlarged schematic view of part B of FIG. 3. (B1) of FIG. 5 is a case where the present polarizing element 100 is used as the polarizing element 12b, and the transparent substrate 1, the optical alignment film 2, and the present polarizing film 3 are arranged in order from the retardation film 13b side. (B2) of FIG. 5 is a case where the present polarizing element 100 is used as the polarizing element 12b, and the present polarizing film 3, the light alignment film 2 and the transparent substrate 1 are arranged in order from the retardation film 13b side.

A backlight unit 19 as a light source is arranged outside the polarizing element 12b. The backlight unit 19 includes a light source, a light guide, a reflection plate, a diffusion sheet, and a viewing angle adjustment sheet. Examples of the light source include an electroluminescence element, a cold cathode tube, a hot cathode tube, a light emitting diode (LED), a laser light source, and a mercury lamp. The type of the polarizing film can be selected according to the characteristics of such a light source.

In the case where the liquid crystal display device 10 is a transmissive liquid crystal display device, white light emitted from a light source in the backlight unit 19 is incident on a light guide body, a forward route is changed by a reflection plate, and diffusion is performed by a diffusion sheet. . The diffused light is adjusted by the viewing angle adjustment sheet in such a manner as to have a desired directivity, and then enters the polarizing element 12 b from the backlight unit 19.

Among non-polarized incident light, only a certain linearly polarized light passes through the polarizing element 12b of the liquid crystal panel. This linearly polarized light is converted into circularly polarized light or elliptically 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, by the presence or absence of a potential difference between the pixel electrode 22 and the opposite transparent electrode 16, the alignment state of the liquid crystal molecules contained in the liquid crystal layer 17 changes, so that the brightness of light emitted from the liquid crystal display device 10 is measured. control. In the case where the liquid crystal layer 17 is in an aligned state in which polarized light is converted and transmitted, the polarized light passes through the liquid crystal layer 17 and the transparent electrode 16, and light of a specific wavelength range passes through the color filter 15 and reaches the polarizing element 12a. The liquid crystal display The device displays the color determined by the color filter in the brightest way.

In contrast, when the liquid crystal layer 17 is in an alignment state that directly transmits polarized light, the light transmitted through the liquid crystal layer 17, the transparent electrode 16, and the color filter 15 is absorbed by the polarizing element 12 a. As a result, the pixel appears black. In the intermediate alignment state between these two states, the brightness of the light emitted from the liquid crystal display device 10 is also in the middle of the above two, so the pixel displays an intermediate color.

In the case where the liquid crystal display device 10 is a transflective liquid crystal display device, it is preferably used on the side of the present polarizing film of the polarizing element and further having a 1/4 wavelength plate (circular polarizing plate) laminated. At this time, the pixel electrode 22 has a transmissive portion formed of a transparent material and a reflective portion formed of a material that reflects light, and the transmissive portion displays an image similarly to the above-mentioned transmissive liquid crystal display device. On the other hand, in the reflection part, external light is incident on the liquid crystal display device, and the polarizing film has the function of a quarter-wave plate. The circularly polarized light transmitted through the polarizing film passes through the liquid crystal layer 17 and is applied by the pixel electrode 22. Used for display.

Next, the present EL display device 30 using the present polarizing film will be described with reference to FIG. 6. When the present polarizing film is used in the EL display device, it is preferable to use the present polarizing film as a circular polarizing plate (hereinafter, sometimes referred to as “the circular polarizing plate”). This circular polarizing plate has two embodiments. Therefore, before explaining the structure and the like of the EL display device 30, two embodiments of the circular polarizing plate will be described with reference to FIG.

FIG. 7A is a schematic view showing a first embodiment of the circular polarizing plate 110. FIG. The first embodiment is a circularly polarizing plate 110 having a retardation layer (a retardation film) 4 provided on the present polarizing film 3 in the present polarizing element 100. (B) of FIG. 7 is a schematic diagram showing a second embodiment of the circular polarizing plate 110. In the second embodiment, the transparent base material 1 (the retardation film 4) provided with the retardation in advance is used as the transparent base material 1 used in the production of the present polarizing element, so that the transparent base material 1 itself serves as a phase. This circular polarizing plate 110 functions as the difference layer 4.

As the present circular polarizing plate including the present polarizing film, if it is the second embodiment of the present circular polarizing plate, the configuration is simple, so it is preferable. In this case, it is preferable to use a 1/4 wavelength plate as a transparent substrate. It is further preferable to use a 1/4 wavelength plate as a transparent substrate and satisfy the following requirements (A1) and (A2).

(A1) The angle formed by the absorption axis of the polarizing film and the retardation axis of the 1/4 wavelength plate is approximately 45 °; (A2) The retardation of the front side of the 1/4 wavelength plate measured by light with a wavelength of 550 nm The value ranges from 100 to 150 nm.

Here, a method of manufacturing the circular polarizing plate 110 will be described. As described above, the second embodiment of the circular polarizing plate 110 can be used as the transparent substrate 1 by using the transparent substrate 1 which is previously provided with retardation in the manufacturing method of the present polarizing film 100. While manufacturing. In the first embodiment of the circular polarizing plate 110, a retardation layer 4 may be formed by bonding a retardation film to the present polarizing film 3 manufactured by the manufacturing method B. When the polarizing film 100 is manufactured in the form of the second roll 220 by the manufacturing method B, the polarizing film 100 may be rolled out from the second roll 220 and cut to a specific size. The form of laminating the retardation film on the cut polarizing film 100 can also be prepared by winding on a core. The third roll of the retardation film is used to continuously manufacture the circular polarizer 110 having a film shape and a long shape.

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 includes the steps of continuously rolling out the polarizing element 100 from the second roll 220 and continuously rolling out the phase difference film from a third roll 230 having a phase difference film wound thereon; A step of continuously bonding the polarizing film provided on the polarizing element 100 rolled up by the roll 220 and the retardation film rolled up from the third roll to form the round polarizing plate 110; and forming the formed round circle A step of obtaining the fourth roll 240 by winding the polarizing plate 110 on the fourth roll core 240A.

The manufacturing method of the first embodiment of the circular polarizing plate 110 has been described above. When bonding the polarizing film 3 and the retardation film in the polarizing element 100, an appropriate adhesive can also be used. The formed adhesive layer adheres the polarizing film 3 and the retardation film.

Next, the EL display device having the circular polarizing plate 110 will be described with reference to FIG. 6 again.

The EL display device 30 is formed by laminating an organic functional layer 36 as a light emitting source and a cathode electrode 37 on a substrate 33 on which a pixel electrode 35 is formed. The circularly polarizing plate 31 is disposed on the opposite side of the organic functional layer 36 so as to sandwich the substrate 33, and the circularly polarizing plate 110 is used as such a circularly polarizing plate 31. A positive voltage is applied to the pixel electrode 35, a negative voltage is applied to the cathode electrode 37, and a direct current is applied between the pixel electrode 35 and the cathode electrode 37, whereby the organic functional layer 36 emits light. The organic functional layer 36 as a light emitting source includes an electron transport layer, a light emitting layer, a hole transport layer, and the like. The light emitted from the organic functional layer 36 passes through the pixel electrode 35, the interlayer insulating film 34, the substrate 33, and the circular polarizing plate 31 (the circular polarizing plate 110). Although the organic EL display device having the organic functional layer 36 is described, it can also 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 into a desired shape on a substrate 33. Then, an interlayer insulating film 34 is formed, and then the pixel electrode 35 is formed into a film and patterned by a sputtering method. Thereafter, the organic functional layer 36 is laminated.

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

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

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

Examples of the substrate 33 include a sapphire glass substrate, a quartz glass substrate, a soda glass substrate, and a ceramic substrate such as alumina; a metal substrate such as copper; and a plastic substrate. Although not shown, a thermally conductive film may be formed on the substrate 33. Examples of the thermally conductive film include a diamond thin film (DLC (Diamond-like carbon)). When the pixel electrode 35 is a reflective type, light is emitted in the opposite direction to the substrate 33. Therefore, not only transparent materials but also opaque materials such as stainless steel can be used. The substrate may be formed in a single form, or may be formed in the form of a laminated substrate by bonding a plurality of substrates with an adhesive. These substrates are not limited to those having a plate shape, and may be films.

As the thin film transistor 40, for example, a polycrystalline silicon transistor or the like may be used. The thin film transistor 40 is disposed at an end portion of the pixel electrode 35 and has a size of about 10 to 30 μm. In addition, the size of the pixel electrode 35 is about 20 μm × 20 μm to 300 μm × 300 μm.

Wiring electrodes of the thin film transistor 40 are provided on the substrate 33. The resistance of the wiring electrode is low, and it has the function of electrically connecting the pixel electrode 35 and suppressing the resistance to a low value. This wiring electrode often contains any one or two or more of Al, Al and a transition metal (excluding Ti), Ti, or titanium nitride (TiN).

An interlayer insulating film 34 is provided between the thin film transistor 40 and the pixel electrode 35. The interlayer insulating film 34 may be any one of the following: those formed of inorganic materials such as silicon oxide such as SiO ₂ and silicon nitride by sputtering or vacuum evaporation; and those using SOG (Spin-on-Glass, Spin-on glass) have insulating properties such as silicon oxide layer, photoresist, coating film of resin materials such as polyimide and acrylic resin.

A rib 41 is formed on the interlayer insulating film 34. The ribs 41 are arranged around the pixel electrode 35 (between adjacent pixels). Examples of the material of the rib 41 include an acrylic resin and a polyimide resin. The thickness of the rib 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 including a pixel electrode 35 as a transparent electrode, an organic functional layer 36 as a light emitting source, and a cathode electrode 37 will be described. The organic functional layer 36 includes at least one hole transporting layer and a light emitting layer, for example, an organic injection transporting layer, a light emitting layer, a hole transporting layer, and a hole injection layer in this order.

Examples of the pixel electrode 35 include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), ZnO, and SnO ₂ And In ₂ O ₃ and the like; particularly preferred is ITO or IZO. In terms of the thickness of the pixel electrode 35, it is sufficient to have a thickness of more than a certain value for sufficient hole injection, and it is preferably set to 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 operation of the electrode Stability, preferably using two components selected from the exemplified metal elements Or three-component alloy system. As the alloy system, for example, 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 are preferable. (Ca: 5 ~ 20 at%) and so on.

The cathode electrode 37 can be 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, and more preferably 1 to 500 nm.

The hole injection layer has a function of facilitating the injection of holes from the pixel electrode 35, and the hole transport layer has a function of transmitting holes and a function of blocking electrons, and is also called a charge injection layer or a charge transport layer.

The thickness of the light emitting layer, the thickness of the hole injection layer plus the hole transport layer, and the thickness of the electron injection transport layer are not particularly limited, and they are different depending on the formation method, and it is preferably set to about 5 to 100 nm. Various organic compounds can be used for the hole injection layer or the hole transport layer. In terms of forming a homogeneous thin film, the formation of the hole injection transport layer, the light emitting layer, and the electron injection transport layer can be performed by a vacuum evaporation method.

The organic functional layer 36 as a light emitting source can be used: those using light emission (fluorescence) from singlet excitons; those using light emission (phosphorescence) from triplet excitons; including light emission (fluorescence) from singlet excitons ) And organic functional layers using luminescence (phosphorescence) from triplet excitons; those formed from organic matter; organic functional layers including those formed from organic matter and those formed from inorganic matter; materials of high molecular weight; materials of low molecular weight; Materials containing high-molecular materials and low-molecular materials. However, the present invention is not limited to this, and various known organic functional layers 36 may be used for the EL display device 30.

A desiccant 38 is disposed in a space between the cathode electrode 37 and the sealing cover 39. The reason is that the organic functional layer 36 is not resistant to moisture. The desiccant 38 absorbs moisture to prevent deterioration of the organic functional layer 36.

FIG. 10 is a schematic view showing a cross-sectional structure 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 so that light can be emitted from the opposite side of the array substrate.

As the thin film sealing film 42, a DLC film having a DLC (Diamond-Like Carbon) vapor-deposited on a film of an electrolytic capacitor is preferably used. DLC film has the characteristics of extremely poor water permeability and high moisture resistance. Alternatively, a DLC film or the like may be directly deposited on the surface of the cathode electrode 37 and formed. Further, the thin film sealing film 42 may be formed by laminating a resin film and a metal film in multiple layers.

According to the above method, the novel polarizing film (the polarizing film) of the present invention and the novel display device (the liquid crystal display device and the EL display device) having the polarizing film can be provided.

Finally, a projection type liquid crystal display device using the polarizing film will be described.

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

This polarizing film is used as the polarizing element 142 and / or the polarizing element 143 of the projection type liquid crystal display device.

The light beam emitted from a light source (for example, a high-pressure mercury lamp) 111 that is a light source is first passed through the first lens array 112, the second lens array 113, the polarization conversion element 114, and the overlapping lens 115 to uniformize the brightness at the cross-section of the beam And polarized.

Specifically, the light beam emitted from the light source 111 is divided into a plurality of minute light beams by the first lens array 112 formed by the minute lenses 112a in a matrix shape. The second lens array 113 and the superimposed lens 115 are provided so that the divided three light beams irradiate the entire three liquid crystal panels 140R, 140G, and 140B as illumination targets. Therefore, the entire surface of the incident side of each liquid crystal panel is substantially uniform. Illumination.

The polarization conversion element 114 includes a polarization beam splitter array, and is disposed between the second lens array 113 and the superimposing lens 115. Thereby, the random polarized light 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 polarizing element described below, and exerting the effect of improving the brightness of the screen.

The light uniformized and polarized as described above is sequentially separated into red channels, green channels, and blue channels by the dichroic mirrors 121, 123, and 132 for separating the three primary colors of RGB through the reflector 122, and They are incident on the liquid crystal panels 140R, 140G, and 140B, respectively.

In the liquid crystal panels 140R, 140G, and 140B, a polarizing element is disposed on an incident side thereof. 142. Polarizing elements 143 are disposed on the emission sides. The polarizing element 142 and the polarizing element 143 can use the present polarizing film.

The polarizing element 142 and the polarizing element 143 arranged on the respective RGB optical paths are arranged so that their respective absorption axes are orthogonal to each other. Each of the liquid crystal panels 140R, 140G, and 140B disposed on each optical path has a function of converting a polarization state controlled for each pixel into a light amount according to an image signal.

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

According to the image data of the liquid crystal panels 140R, 140G, and 140B, the incident light is transmitted at a different transmittance corresponding to each pixel, and the optical image thus formed is synthesized by the cross dichroic color 150 and projected The lens 170 magnifies and projects to the screen 180.

Examples of electronic paper include: those exhibited by molecules such as optical anisotropy and dye molecule alignment; those exhibited by particles such as electrophoresis, particle movement, particle rotation, and phase change; and movement by one end of a film The displayer; the displayer by the coloration / phase transition of the molecule; the displayer by the light absorption of the molecule; the displayer by self-luminescence by the coupling of electrons and holes. More specifically, microcapsule type electrophoresis, horizontal movement type electrophoresis, vertical movement type electrophoresis, spherical torsion ball, magnetic torsion ball, cylindrical torsion ball method, charged toner, electron powder fluid, magnetic swimming type, magnetic Thermal, electrowetting, light scattering (transparent / white turbidity change), cholesteric liquid crystal / photoconductive layer, cholesteric liquid crystal, bistable nematic liquid crystal, ferroelectric liquid crystal, two-color pigment-liquid crystal dispersion type, movable film 5. Use of leuco dyes for color development, photochromism, electrochromism, electrodeposition, flexible organic EL, etc. E-paper can be used not only for personal use of text or images, but also for advertisement display (signage). With this polarizing film, the thickness of the electronic paper can be made thin.

As a stereoscopic display device, for example, a method of alternately arranging different retardation films like a micro magnetic pole method has been proposed (Japanese Patent Laid-Open No. 2002-185983). The light film can be easily patterned by printing, inkjet, photolithography, etc., so the manufacturing steps of the display device can be shortened, and no retardation film is required.

[Example]

Hereinafter, the present invention will be described in more detail through examples. "%" And "part" in the examples are mass% and mass part unless otherwise noted.

In this example, the following dichroic pigment (1) was used.

Production of compound (1-1) (compound shown in (1-1) below)

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

5.00 g of a compound [compound (1B)] represented by formula (1B), 4.63 g of ethyl 4-hydroxybenzoate, 0.23 g of dimethylaminopyridine (DMAP), and 25 g of chloroform were mixed, and in a light-shielded nitrogen environment Stir at 5 ° C for 10 minutes. 2.58 g of diisopropylcarbodiimide (IPC) was added dropwise to the obtained mixed solution over 5 minutes, and the mixture was stirred for 4 hours. 75 g of methanol was added to the obtained reaction solution to perform crystallization, and the crystals were collected by filtration. The crystals were further washed with an equal amount of methanol, and then vacuum-dried to obtain 6.78 g of a compound (1-1). The yield was 87% based on the 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).

Production of compound (1-7) (compound shown in (1-7) below)

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

5.00 g of compound (1B), 4.63 g of 4-butoxyphenol, 0.23 g of DMAP, and 25 g of chloroform were mixed and stirred at 5 ° C. for 10 minutes under a light-shielding-nitrogen environment. 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 to perform crystallization, and the crystals were collected by filtration. The crystals were dissolved in 50 g of dimethylacetamide, and the insoluble matter was filtered through wollastonite. The filtrate was recovered and crystallized using water. The obtained crystal was further dissolved in 50 g of tetrahydrofuran, and insoluble matters were removed by filtration. Then, heptane was added for crystallization, and vacuum drying was performed to obtain 4.66 g of compound (1-7). The yield was 60% based on the 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).

In this example, the following polymerizable liquid crystal compounds were used.

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

Compound (4-6) was synthesized by the method described in Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996).

[Measurement of phase transition temperature]

The phase transition temperature of the compound (4-6) was confirmed by determining the phase transition temperature of the film containing the compound (4-6). Its operation is as follows.

A film containing the compound (4-6) was formed on a glass substrate on which an alignment film was formed, and the phase transition temperature was confirmed by observation of the texture with a polarizing microscope (BX-51, manufactured by Olympus) while heating. After the film containing the compound (4-6) was heated to 120 ° C, the phase transition was changed to a nematic phase at 112 ° C, the phase transition to a smectic phase A at 110 ° C, and the phase transition to a layer at 94 ° C when the temperature was lowered. Phase B.

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

The compound (4-8) is synthesized by referring to the synthesis method of the compound (4-6).

[Measurement of phase transition temperature]

The phase transition temperature of the compound (4-8) was confirmed in the same manner as the phase transition temperature measurement of the compound (4-6). After the compound (4-8) is heated to 140 ° C, when the temperature is lowered, the phase is transferred to a nematic phase at 131 ° C, the phase is transferred to a smectic phase A at 80 ° C, and the phase is transferred to a smectic phase B at 68 ° C .

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

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

[Measurement of phase transition temperature]

The phase transition temperature of the compound (4-22) was confirmed in the same manner as the phase transition temperature measurement of the compound (4-6). After the compound (4-22) is heated to 140 ° C, the phase transition is a nematic phase at 106 ° C, a phase transition to a smectic A phase at 103 ° C, and a phase transition to a smectic B phase at 86 ° C when the temperature is reduced. .

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

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

[Measurement of phase transition temperature]

The phase transition temperature of the compound (4-25) was confirmed in the same manner as the phase transition temperature measurement of the compound (4-6). After the compound (4-25) is heated to 140 ° C, when the temperature is lowered, the phase is transferred to a nematic phase at 119 ° C, the phase is transferred to a smectic A phase at 100 ° C, and the phase is transferred to a smectic B phase at 77 ° C. .

Example 1 [Preparation of Composition (A) for Polarizing Film Formation]

The following components were mixed and stirred at 80 ° C. for 1 hour, thereby obtaining a polarizing film-forming composition (A). Furthermore, the "compound (1-7)" of the so-called dichroic pigment used here, This means a compound represented by the above formula (1-7), and other compounds used as dichroic pigments are also numbered according to the formula. The same applies to the following.

1. X-ray diffraction measurement

A 2 mass% aqueous solution (composition for forming an alignment layer) of polyvinyl alcohol (polyvinyl alcohol 1000 fully saponified type, manufactured by Wako Pure Chemical Industries, Ltd.) was applied to a glass substrate by a spin coating method, and dried. A film with a thickness of 100 nm was formed. Then, an alignment layer is formed by performing a rubbing treatment on the surface of the obtained film. The friction treatment system uses a semi-automatic friction device (trade name: LQ-008 type, manufactured by Changyang Engineering Co., Ltd.), using a cloth (trade name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.) at a press-in amount of 0.15 mm, speed 500 rpm, 16.7 mm / s. The polarizing film-forming composition (A) was coated on the thus-produced alignment film by a spin coating method, and heated and dried on a hot plate at 120 ° C for 1 minute, and then quickly cooled to room temperature, and then applied to the above-mentioned alignment layer. A dry film was formed thereon. Then, a UV irradiation device (SPOT CURE SP-7: manufactured by Ushio Denki Co., Ltd.) was used to irradiate the dried film with ultraviolet rays at an exposure amount of 2000 mJ / cm ² (based on a 365 nm), thereby exposing the dried film to ultraviolet rays. The polymerizable liquid crystal compound contained is polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal composition, and a polarizing film is formed from the dried film. The thickness of the polarizing film at this time was measured with a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 1.7 μm.

Using an X-ray diffraction device X 'Pert PRO MPD (manufactured by Spectris Co., Ltd.), the same X-ray diffraction measurement was performed on this polarizing film. As a result, a full-width at half maximum (FWHM, Full Width at Half Maximum) = Steep diffractive crests (Blegg crests) of about 0.17 °. In addition, the same results were obtained with the incidence from the rubbing vertical direction. The order period (d) obtained from the peak position was about 4.4 Å, and it was confirmed that a structure reflecting a higher-order stratified phase was formed.

2. Fabrication of light alignment film on transparent film

A cellulose triacetate film (KC8UX2M, manufactured by Konica Minolta Co., Ltd.) was used as a transparent substrate, and the photo-alignment polymer represented by the following formula (3) was dissolved in toluene to 5 by coating by a bar coating method. % Of the liquid, and dried at 120 ° C to obtain a dry film. This dried coating was irradiated with polarized UV to obtain a photo-alignment film. Polarized UV treatment was performed using a UV irradiation device (SPOT CURE SP-7: manufactured by Ushio Denki Co., Ltd.) under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ.

3. Production of polarizing film

The polarizing film-forming composition (A) was coated on the film with a light alignment film obtained in the above manner by a rod coating method (# 5 17 mm / s) and heated in a drying oven at 120 ° C. After drying for 1 minute, it was cooled to room temperature. Next, a UV irradiation device (SPOT CURE SP-7: manufactured by Ushio Denki Co., Ltd.) was used to irradiate the layer formed of the composition for forming a polarizing film with ultraviolet rays having an exposure amount of 2000 mJ / cm ² (based on 365 nm), thereby The polarizable film is formed from the dried coating film by polymerizing the polymerizable liquid crystal compound contained in the dried coating film while maintaining the liquid crystal state of the polymerizable liquid crystal composition. The thickness of the polarizing film at this time was measured with a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 1.6 μm. The obtained person is a polarizing element including a polarizing film and a transparent substrate.

4. Measurement of Polarization, Transmittance and Hue

In order to confirm the usefulness of the polarizing element, visibility-corrected polarization, visibility-corrected transmittance, chromaticity a ^* value, chromaticity b ^* value, orthogonal _a ^*, and orthogonal b ^* were measured as follows.

Used in a spectrophotometer (made by Shimadzu Corporation, UV-3150) equipped with a clip attached to a polarizing element, and measured through the transmission axis in the range of 380 nm to 780 nm by the dual beam method Transmission (T ¹ ) and transmission (T ² ) in the direction of the absorption axis. The clip is provided with a mesh on the reference side to reduce the amount of light by 50%. Use the following equations (Equation 1) and (Equation 2) to calculate the transmittance and polarization of a single object at each wavelength, and then perform visibility correction using the 2-degree field of view (C light source) of JIS Z 8701 to calculate the visibility-corrected single object. Transmittance (Ty) and visibility correction polarization (Py). In addition, using the color matching function of the C light source, the chromaticities a ^* and b ^* in the L ^* a ^* b ^* (CIE) colorimetric system were calculated from the single object transmittance measured in the same manner. Furthermore, using the color matching function of the C light source, the orthogonal a ^* and orthogonal b ^* in the L ^* a ^* b ^* (CIE) colorimetric system were calculated from the orthogonal transmittance measured in the same manner. The closer the values of chromaticity a ^* , chromaticity b ^* , orthogonal a ^*, and orthogonal b ^* to 0, the more neutral the hue can be determined. The results are shown in Table 4.

Single object penetration rate (%) = (T1 + T2) / 2 (Equation 1)

Polarization (%) = (T1-T2) / (T1 + T2) × 100 (Eq. 2)

Example 2

1. Production of polarizing film

Change the line width and coating speed of the rod coater (# 7 15 mm / s), In addition, a polarizing film was produced in the same manner as in Example 1. The thickness of the polarizing film at this time was measured with a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 1.8 μm.

2.Measurement of polarization, transmittance and hue

The visibility-corrected single-object transmittance (Ty), visibility-corrected polarization (Py), chromaticity a ^* , chromaticity b ^* , orthogonality a ^*, and the polarization-corrected single object transmittance (Ty) were measured by the same method as in Example 1. Orthogonal b ^* , and the result is shown in Table 4.

Example 3 [Preparation of Composition (B) for Polarizing Film Formation]

The following components were mixed and stirred at 80 ° C. for 1 hour, thereby obtaining a polarizing film-forming composition (B).

1. Production of polarizing film

In addition to changing the polarizing film-forming composition (A) to the polarizing film-forming composition (B), and further changing the line width and coating speed (# 5 25 mm / s) of the rod coater A polarizing film was produced in the same manner as in Example 1. Using a laser microscope (Olympus shares Co., Ltd., OLS3000) The film thickness of the polarizing film at this time was measured, and it was 1.7 μm.

2.Measurement of polarization, transmittance and hue

The visibility-corrected single-object transmittance (Ty), visibility-corrected polarization (Py), chromaticity a ^* , chromaticity b ^* , orthogonality a ^*, and the polarization-corrected single object transmittance (Ty) were measured by the same method as in Example 1. Orthogonal b ^* , and the result is shown in Table 4.

Example 4

1. Production of polarizing film

A polarizing film was produced in the same manner as in Example 3 except that the line width of the rod and the coating speed (# 7 20 mm / s) were changed. The thickness of the polarizing film at this time was measured with a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 2.0 μm.

2.Measurement of polarization, transmittance and hue

The visibility-corrected single-object transmittance (Ty), visibility-corrected polarization (Py), chromaticity a ^* , chromaticity b ^* , orthogonality a ^*, and the polarization-corrected single object transmittance (Ty) were measured by the same method as in Example 1. Orthogonal b ^* , and the result is shown in Table 4.

Example 5

1. Production of black polarizing film

A polarizing film was produced in the same manner as in Example 3 except that the line width of the rod and the coating speed (# 5 50 mm / s) were changed. The thickness of the polarizing film at this time was measured with a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 2.2 μm.

2.Measurement of polarization, transmittance and hue

The visibility-corrected single-object transmittance (Ty), visibility-corrected polarization (Py), chromaticity a ^* , chromaticity b ^* , orthogonality a ^*, and the polarization-corrected single object transmittance (Ty) were measured by the same method as in Example 1. Orthogonal b ^* , and the result is shown in Table 4.

Example 6 [Preparation of Composition (C) for Forming Polarizing Film]

The following components were mixed and stirred at 80 ° C. for 1 hour, thereby obtaining a polarizing film-forming composition (C).

1. Production of polarizing film

In addition to changing the polarizing film-forming composition (A) to the polarizing film-forming composition (C), and further changing the line width and coating speed (# 7 20 mm / s) of the rod coater A polarizing film was produced in the same manner as in Example 1. The thickness of the polarizing film at this time was measured with a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 2.0 μm.

2.Measurement of polarization, transmittance and hue

The visibility-corrected single-object transmittance (Ty), visibility-corrected polarization (Py), chromaticity a ^* , chromaticity b ^* , orthogonality a ^*, and the polarization-corrected single object transmittance (Ty) were measured by the same method as in Example 1. Orthogonal b ^* , and the result is shown in Table 4.

Example 7

1. Production of black polarizing film

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

2.Measurement of polarization, transmittance and hue

The visibility-corrected single object transmittance (Ty), visibility-corrected polarization (Py), chromaticity a ^* , chromaticity b ^* , orthogonality a ^* and Orthogonal b ^* , and the result is shown in Table 4.

Comparative Example 1

1. Production of iodine-PVA polarizer

A polyvinyl alcohol film having an average degree of polymerization of about 2,400, a degree of saponification of more than 99.9 mol%, and a thickness of 75 μm was stretched to about 5 times in a dry uniaxial manner, and then immersed in pure water at 60 ° C while maintaining the stretched state After 1 minute, it was immersed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.1 / 5/100 at 28 ° C. for 60 seconds. Thereafter, it was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 810.5 / 7.5 / 100 at 72 ° C. for 300 seconds. Then, it was washed with pure water at 10 ° C. for 5 seconds, and then dried at 80 ° C. for 3 minutes to obtain a polarizing element having iodine adsorbed and aligned on the polyvinyl alcohol resin film.

2.Measurement of polarization, transmittance and hue

The visibility-corrected single-object transmittance (Ty), visibility-corrected polarization (Py), chromaticity a ^* , chromaticity b ^* , orthogonality a ^*, and the polarization-corrected single object transmittance (Ty) were measured by the same method as in Example 1. Orthogonal b ^* , and the result is shown in Table 4.

It can be known from Table 4 that the polarizing films of Examples 1 to 7 are thinner than the previous iodine-PVA polarizing element. The polarizing films of Examples 1 to 7 all exhibited neutral hue.

Example 8

1. Fabrication of light alignment film on retardation film

Use retardation film (uniaxially stretched film WRF-S (modified polycarbonate resin), retardation value 137.5 nm, thickness 50 μm, manufactured by Teijin Chemical Co., Ltd.) instead of cellulose triacetate film (KC8UX2M, Konica Minolta Co., Ltd.) As a transparent substrate, a liquid obtained by dissolving the photo-alignment polymer represented by the above formula (3) in cyclopentanone to 5% is applied by a bar coating method, and the temperature is 120 ° C. Drying to obtain a dry film. This dried coating was irradiated with polarized UV to obtain a photo-alignment film. Polarized UV treatment was performed using a UV irradiation device (SPOT CURE SP-7: manufactured by Ushio Denki Co., Ltd.) under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ. In this case, the irradiation direction of the polarized UV is carried out so that it is 45 ° with respect to the retardation axis of the retardation film.

2. Production of circular polarizer

The polarizing film-forming composition (C) was coated on the prepared light alignment film with a retardation film with a light alignment film by a rod coating method (# 7 20 mm / s), and the temperature was 120 ° C. After heating and drying in a drying oven for 1 minute, it was cooled to room temperature. Then, a UV irradiation device (SPOT CURE SP-7: manufactured by Ushio Denki Co., Ltd.) was used to irradiate the layer formed of the composition for forming a polarizing film with ultraviolet rays with an exposure amount of 2000 mJ / cm ² (based on 365 nm), thereby The polymerizable liquid crystal compound contained in the dry coating film is polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal composition, thereby forming a polarizing film from the dry coating film, thereby producing a circularly polarizing plate. The thickness of the polarizing film at this time was measured with a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 2.0 μm.

3. Confirmation of anti-reflection performance

The retardation film side of the circularly polarizing plate and the aluminum metal plate obtained through the bonding of the adhesive, as a result, the metallic luster observed on the aluminum metal plate element disappeared, and a uniform black display was obtained. It can be seen that the circularly polarizing plate made from the polarizing film in this way has good anti-reflection characteristics.

[Industrial availability]

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

Claims (15)

A polarizing film comprising: a polymer formed of a polymerizable liquid crystal compound; and when dispersed in the polymer and measuring light absorption, at least one type 2 having a maximum absorption in a wavelength range of 380 to 550 nm Chromatic pigment (1); and at least two dichroic pigments (2) having absorption maximum in the wavelength range of 550 to 700 nm; the above dichroic pigment (2) includes the compound represented by formula (2):

[In formula (2), n is 1 or 2; Ar ¹ and Ar ³ are each independently a group represented by any of formula (AR-1) to formula (AR-4):

Ar ² is the base represented by formula (AR2-1), formula (AR2-2) or formula (AR2-3):

A ₁ and A ₂ are independently the bases represented by any one of formula (A-1) to formula (A-9), and * represents a bonding bond:

(mc is an integer from 0 to 10, when there are two mcs in the same base, the two mcs are the same or different from each other)]. The polarizing film according to claim 1, wherein the above 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 the wavelength range of 400 to 550 nm . The polarizing film as claimed in claim 1 or 2, wherein at least two dichroic pigments (2) containing the absorption maximum in the wavelength range of 550 to 700 nm when dispersed in the above polymer and measuring light absorption : Dichroic pigment (2-1) with absorption maximum in the wavelength range of 550-600nm, and dichroic pigment (2-2) with absorption maximum in the wavelength range of 600-700nm. The polarizing film according to claim 1 or 2, wherein the polymerizable liquid crystal compound is a compound showing a smectic liquid crystal phase. If the polarizing film of claim 1 or 2 is obtained, the Bragg wave peak can be obtained in the X-ray diffraction measurement. If the polarizing film of claim 1 or 2, wherein the color coordinates a ^* value and b ^* value in the L ^* a ^* b ^* color representation system satisfy the relationship of the following formula (1F) and formula (2F): -3 ≦ chromaticity a ^* ≦ 3 (1F) -3 ≦ chromaticity b ^* ≦ 3 (2F). The polarizing film according to claim 1 or 2, wherein the dichroic dye (1) and the dichroic dye (2) are azo compounds. The polarizing film according to claim 1, wherein the dichroic pigment (1) includes the compound represented by formula (1):

[In formula (1), Y is the base represented by formula (Y1) or formula (Y2):

(In the formula, L is an oxygen atom or -NR-, R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) R ¹ is any ^one of formula (R ¹ -1) to formula (R ¹ -3) The basis expressed:

(In the formula, ma is an integer from 0 to 10, when there are two ma in the same base, the two ma are the same or different from each other; * represents a bonding bond) R ² is the formula (R ² -1) ~ The base expressed by any one of formula (R ² -6):

(In the formula, mb is an integer from 0 to 10)]. A polarizing element formed by disposing a polarizing film according to any one of claims 1 to 8 on a transparent substrate. A manufacturing method, which is a method of manufacturing a polarizing element according to claim 9, and includes: a step of preparing a laminate including an alignment film on the transparent substrate; and applying a composition on the alignment film of the laminate Step, the composition includes: a polymerizable liquid crystal compound; when dispersed in a polymer formed of the polymerizable liquid crystal compound and measuring light absorption, one or two with a maximum absorption in the wavelength range of 380 to 550 nm Chromatic pigment (1), and two dichroic pigments (2) having absorption maximum in the wavelength range of 550 to 700 nm; and a solvent; and polymerizing the polymerizable liquid crystal compound contained in the composition step. The manufacturing method according to claim 10, wherein the transparent substrate is a plastic substrate, and the alignment film is a light alignment film. A liquid crystal display device comprising the polarizing film according to any one of claims 1 to 8. A circular polarizing plate comprising the polarizing film and the λ / 4 layer according to any one of claims 1 to 8 and satisfying the following requirements (A1) and (A2): (A1) The absorption axis of the polarizing film and the above The angle formed by the late phase axis of the λ / 4 layer is approximately 45 °; (A2) The front retardation value of the λ / 4 layer measured by light with a wavelength of 550 nm is in the range of 100 to 150 nm. An organic EL display device including the circular polarizing plate as claimed in claim 13 and an organic EL element. A polarizing film comprising: a polymer formed of a polymerizable liquid crystal compound; and when dispersed in the polymer and measuring light absorption, at least one type 2 having a maximum absorption in a wavelength range of 380 to 550 nm Chromatic pigment (1); and at least two dichroic pigments (2) with absorption maximum in the wavelength range of 550 to 700 nm; the above dichroic pigment (1) includes the compound represented by formula (1):

[In formula (1), Y is the base represented by formula (Y1) or formula (Y2):

(In the formula, L is an oxygen atom or -NR-, R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms); R ¹ is any ^one of formula (R ¹ -1) to formula (R ¹ -3) The basis of the expression:

(In the formula, ma is an integer from 0 to 10, when there are two ma in the same base, the two ma are the same or different from each other; * represents a bonding bond); R ² is the formula (R ² -1 ) ~ The base expressed by any one of formulas (R ² -6):

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