TW201344255A - Polarizing film, circular polarizing plate, and the like - Google Patents

Abstract

The present invention provides a polarizing film which is easy to be thinned and which is excellent in hue of neutral, a polarizing element including the polarizing film, a method for producing the same, and the like. The present invention provides a polarizing film comprising: a polymer formed of a polymerizable liquid crystal compound; and a method of producing a polarizing film comprising the polarizing film; and measuring the light absorption by dispersing in the polymer At least one dichroic dye (1) having an absorption maximum in a wavelength range of 380 to 550 nm, and at least two dichroic dyes having an absorption maximum in a wavelength range of 550 to 700 nm ( 2). The dichroic dye (2) is preferably a dichroic dye having absorption in a wavelength range of 550 to 600 nm and a dichroic dye having absorption in a wavelength range of 600 to 700 nm.

Description

Polarizing film, circular polarizing plate, and the like

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

The polarizing element used in the liquid crystal display device has a high transmittance and a degree of polarization, and is widely used as a polyvinyl alcohol dyed by a dichroic dye such as iodine and subjected to elongation treatment (Polyvinyl Alcohol) , polyvinyl alcohol)) film (polarizing film). For example, Patent Document 1 discloses a polarizing film containing iodine-stained PVA.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 7- 14170

However, the polarizing film containing iodine-stained PVA has a problem that it is easy to yellow, that is, a so-called neutral hue. Further, the polarizing film containing iodine-stained PVA is difficult to be thinned, and there is a limit in application to a recent display device which is required to be thinner. Therefore, an object of the present invention is to provide a polarizing film which is easy to be thinned and which is excellent in hue of neutral, a polarizing element including the polarizing film, a method for producing the same, and the like.

The invention includes the following invention.

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

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

[3] The polarizing film according to [1] or [2], wherein at least two kinds of dichroism having an absorption maximum value in a wavelength range of 550 to 700 nm when dispersed in the above polymer to measure light absorption The dye (2) includes a dichroic dye (2-1) having an absorption maximum in a wavelength range of 550 to 600 nm when the light absorption is measured by being dispersed in the polymer, and a wavelength of 600~. A dichroic dye (2-2) having an absorption maximum in the range of 700 nm.

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

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

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

-3 ≦ b b ^* ≦ 3 (2F).

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

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

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

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

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

(mc is an integer from 0 to 10, and when there are 2 mcs in the same base, the two mcs are identical or different from each other)].

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

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

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

R ¹ is a group represented by any one of the formulae (R ¹ -1) to (R ¹ -3):

(wherein, ma is an integer from 0 to 10, and when there are two ma in the same base, the two ma are the same or different from each other; * indicates a bond key)

R ² is a group represented by any one of the formulae (R ² -1) to (R ² -6):

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

[10] A polarizing element obtained by providing the polarizing film according to any one of [1] to [9] on a transparent substrate.

[11] A method for producing a polarizing element according to [10], comprising: a step of preparing a laminate including an alignment film on a transparent substrate; and coating a combination on the alignment film of the laminate a step of containing a polymerizable liquid crystal compound; and having a maximum absorption value in a wavelength range of 380 to 550 nm when dispersed in a polymer formed of the polymerizable liquid crystal compound to measure light absorption a dichroic dye (1) and two kinds of dichroic dyes (2) having an absorption maximum in a wavelength range of 550 to 700 nm; and a solvent; and the above-mentioned polymerizability contained in the above composition The step of polymerizing the liquid crystal compound.

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

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

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

[15] An organic EL (Electroluminescence) display device comprising the circular polarizing plate of [14] and an organic EL element.

According to the present invention, it is possible to provide a polarizing film which is easy to be thinned and which is excellent in hue of neutral, 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 elements

13a, 13b‧‧‧ phase difference layer

14a, 14b‧‧‧substrate

15‧‧‧Color filters

16‧‧‧Transparent electrode

17‧‧‧Liquid layer

18‧‧‧Interlayer insulating film

19‧‧‧Backlight unit

20‧‧‧Black matrix

21‧‧‧film transistor

22‧‧‧pixel electrode

23‧‧‧ spacers

30‧‧‧EL display device

31‧‧‧Polar polarizer

32‧‧‧ phase difference film

33‧‧‧Substrate

34‧‧‧Interlayer insulating film

35‧‧‧pixel electrode

36‧‧‧ organic functional layer

37‧‧‧Cathode electrode

38‧‧‧Drying agent

39‧‧‧ Sealing cover

40‧‧‧film transistor

41‧‧‧ rib

42‧‧‧film sealing film

44‧‧‧EL display device

100‧‧‧This polarizing element

110‧‧‧round polarizing plate

111‧‧‧Light source

112‧‧‧1st lens array

112a‧‧ lens

113‧‧‧2nd lens array

114‧‧‧Polarized light conversion element

115‧‧‧Overlapping lens

121, 123, 132‧ ‧ dichroic mirror

122‧‧‧Mirror

140R, 140G, 140B‧‧‧ LCD panel

142, 143‧‧‧ polarizing elements

150‧‧‧Intersection dichroism

170‧‧‧Projection lens

180‧‧‧ screen

210‧‧‧1st reel

210A‧‧‧core

211A, 211B‧‧‧ coating device

212A, 212B‧‧‧ drying oven

213A‧‧‧Polarized UV irradiation device

213B‧‧‧Lighting device

220‧‧‧2nd reel

220A‧‧‧core

230‧‧‧3rd reel

230A‧‧‧core

240‧‧‧4th reel

240A‧‧‧core

300‧‧‧Auxiliary roller

A‧‧‧Magnification

B‧‧‧Magnification

C‧‧‧Magnification

D1‧‧ Direction

D2‧‧ Direction

Fig. 1 is a schematic view showing a continuous manufacturing method of a polarizing element (this polarizing element) including a polarizing film of the present invention.

Fig. 2 is a schematic view showing the relationship between the alignment direction D2 of the photo-alignment film and the film transport direction D1.

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

4(A1) and (A2) are schematic diagrams showing the order of layers of the present polarizing element used in the liquid crystal display device of Fig. 3.

5(B1) and (B2) are schematic diagrams showing the order of layers 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 configuration of an EL display device using the polarizing film of the present invention.

7(A) and 7(B) are schematic views showing a cross-sectional configuration 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 production method of a circularly polarizing plate (this circular polarizing plate) including the polarizing film of the present invention.

9(C1) and (C2) are schematic views showing the order of layers 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 configuration of an EL display device using the polarizing film of the present invention.

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

The polarizing film of the present invention (hereinafter sometimes referred to as "the present polarizing film") is characterized by comprising a polymer formed of a polymerizable liquid crystal compound and a specific three or more kinds of dichroic dyes. The polarizing film is preferably formed of a composition containing a polymerizable liquid crystal compound and the above three or more kinds of dichroic dyes (hereinafter sometimes referred to as "a composition for forming a polarizing film"). First, the composition for forming a polarizing film will be described.

1. Composition for forming a polarizing film

As described above, the polarizing film-forming composition of the present invention preferably contains a polymerizable liquid crystal compound and three or more kinds of dichroic dyes, and further contains a solvent. The present polarizing film formed of such a composition for forming a polarizing film is easily thinned. First, each constituent component contained in the composition for forming a polarizing film will be described.

1-1. Dichromatic pigment

The dichroic dye contained in the composition for forming a polarizing film contains an absorption maximum in a wavelength range of 380 to 550 nm when it is dispersed in a polymer formed of a polymerizable liquid crystal compound to measure light absorption. At least one dichroic dye (1); and at least two dichroic dyes (2) having an absorption maximum in the range of 550 to 700 nm in the same measurement.

1-1-1. Dichromatic pigment (1)

When the dichroic dye (1) is used to measure light absorption by being dispersed in a polymer formed of a polymerizable liquid crystal compound, it has an absorption maximum in a wavelength range of 380 to 550 nm. In addition, the measurement may be carried out by replacing the dichroic dye of the composition for forming a polarizing film of the present invention with the dichroic dye for measuring the maximum absorption value. The composition for measuring a large absorption value is formed into a film for measuring an absorption maximum value by the same method as the method of forming the polarizing film by the composition for forming a polarizing film described below, and measuring the light absorption of the film for measuring the maximum absorption value. . The specific method for determining the maximum absorption value is the same as the method described in the examples of the present invention.

Examples of the dichroic dye (1) include an azo compound. The compound represented by the above formula (1) (hereinafter sometimes referred to as "compound (1)") is exemplified.

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

Y in the formula (1) is a group represented by the above formula (Y1) or (Y2), and is preferably a group represented by the formula (Y1). In the formulas (Y1) and (Y2), the straight line at both ends represents a bond bond, the bond bond on the left side has a phenyl bond with an azo group, the bond bond on the right side and a benzene group having 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 a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group. Among them, L is preferably an oxygen atom or -NH-, and further preferably an oxygen atom.

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

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

The compound represented by the following formula (1-1) to formula (1-8), etc. are mentioned as a preferable compound (1).

Among them, preferred are compounds represented by the formula (1-1), the formula (1-2), the formula (1-3), the formula (1-5), the formula (1-7), and the formula (1-8). More preferably, it is a compound represented by the formula (1-1), the formula (1-2), the formula (1-3), and the formula (1-7).

When the dichroic dye (1) has a light absorption by the above measurement, it has an absorption maximum in a wavelength range of 380 to 550 nm, and preferably has an absorption maximum in a wavelength range of 400 to 550 nm. More preferably, it has an absorption maximum in a wavelength range of 400 to 520 nm, and preferably has an absorption maximum in a wavelength range of 430 to 520 nm, and particularly preferably has a maximum absorption in a wavelength range of 440 to 510 nm. value. If it is in the above range If the absorption maximum value is present, a plurality of compounds (1) may be used as the dichroic dye (1).

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

In the above formula, R ¹ , R ² and Y have the same meanings as described above, and Re ¹ and Re ² react with each other to form a group 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 phosphonium group and a hydroxyl group, a fluorenyl group and an amine group. A combination of an amine group may be substituted by R, a combination of a carbonyloxyalkyl group and a hydroxyl group, a carbonyloxyalkyl 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 The compound which protects R ^{2 is} mutually reacted, and then the appropriate deprotection reaction is carried out to produce the compound (1).

The reaction conditions in the case of reacting the compound (1X) and the compound (1Y) can be appropriately selected according to the type of the compound (1X) and the compound (1Y) to be used.

For example, as a reaction condition in the case where Re ¹ is a carboxyl group, Re ² is a hydroxyl group, and Y is -C(=O)-O-, for example, a condition in which a condensation is carried out in the presence of an esterification condensing agent in a solvent is exemplified. . The solvent is a solvent which can 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 further use a base such as dimethylaminopyridine (DMAP). The reaction temperature can be selected depending on the kind of the compound (1X) and the compound (1Y), and examples thereof include a range of -15 to 70 ° C, preferably 0 to 40 ° C. The reaction time is, for example, in the range of 15 minutes to 48 hours.

The reaction time may also be a suitable sampling of the reaction mixture in the middle of the reaction, and the degree of disappearance of the compound (1X) and the compound (1Y), or the compound (by a known analytical method such as liquid chromatography or gas chromatography). 1) The degree of generation is confirmed by confirmation.

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

1-1-2. Dichromatic pigment (2)

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

The dichroic dye (2) is contained in the polarizing film-forming composition, and more preferably contains a dichroic dye (2-1) having an absorption maximum in a wavelength range of 550 to 600 nm. A dichroic dye (2-2) having an absorption maximum in the range of 600 to 700 nm. Here, the dichroic dye (2-1) further preferably has an absorption maximum in a wavelength range of 570 to 600 nm, and the dichroic dye (2-2) is preferably at a wavelength of 600 to 680 nm. There is an absorption maximum in the range.

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 the dichroic dye (2-1) can be determined. Specific examples of the dichroic dye (2-1) include the compound (2) represented by a combination of the respective groups in Table 1. The compound (2-1) showing a combination of the respective groups in Table 1 represents a case where n in the formula (2) is 1. In addition, in Table 1, for example, the base represented by the formula (AR-1) is described as "(AR-1)" or the like.

Then, in the combination of the respective groups of the compound (2), Ar ¹ , Ar ² and Ar ³ are combined by the absorption of the compound (2) in the range of 600 to 700 nm in the above measurement. The compound (2) which can be used as the dichroic dye (2-2) is determined. Specific examples of the dichroic dye (2-2) include the compound (2) represented by a combination of the respective groups in Table 2. The compound (2-2) showing a combination of the respective groups in Table 2 represents a case where n in the formula (2) is 1. Further, the description of the basis in Table 2 is the same as in the case of Table 1.

Here, when the compound (2) is specifically represented, the formula (2-11) to the formula (2) 39) Compounds and the like indicated.

In the specific example of the compound (2) exemplified herein, the dichroic dye (2-1) is preferably one of the formula (2-12), the formula (2-13), and the formula (2-18). Formula (2-20), formula (2-21), formula (2-22), Formula (2-23), Formula (2-24), Formula (2-26), Formula (2-27), Formula (2-28), Formula (2-29), and Formula (2) 2-30) As the dichroic dye (2-2), it is preferable to use the formula (2-31), the formula (2-32), the formula (2-33), and the formula (2-34). ), the formula (2-35) and the formula (2-36) are indicated. Furthermore, the formulas represented by the formulas (2-11), (2-15), and (2-16), respectively, do not exhibit an absorbed pigment at a wavelength of 550 to 700 nm, but may be supplemented by a formula ( 1) The pigment is used in combination.

In the specific example of the compound (2), the dichroic dye (2) contained in the composition for forming a polarizing film is more preferably represented by the formula (2-15), the formula (2-16), or the formula (2). -18), formula (2-20), formula (2-21), formula (2-22), formula (2-23), formula (2-27), formula (2-29), formula (2- 31), expressed by formula (2-32), formula (2-33), formula (2-34), and formula (2-35). In the above, when the dichroic dye (2) is represented by a combination of two or more selected from the specific examples of the compound (2), the mixing ratio is shown in Table 3, for example. In the table 3, for example, the compound (2) represented by the formula (2-11) is represented by "(2-11)".

The content of the dichroic dye (1) in the composition for forming a polarizing film is preferably 100 parts by mass or less, more preferably 0.1 parts by mass or more, based on 100 parts by mass of the polymerizable liquid crystal compound described below. The amount is preferably 0.1 parts by mass or more and 5 parts by mass or less.

The content of the dichroic dye (2) in the composition for forming a polarizing film is preferably 10 parts by mass or less, more preferably 0.1 part by mass or more, based on 100 parts by mass of the polymerizable liquid crystal compound described below. It is more preferably 0.1 part by mass or more and 3 parts by mass or less, in parts by mass or less.

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

When the content of each of the dichroic dyes is in the above range, the dichroic dye in the composition for forming a polarizing film exhibits sufficient solubility in the solvent. Therefore, when the polarizing film is produced using the composition for forming a polarizing film. The present polarizing film can be obtained without causing defects. In addition, as described above, the composition for forming a polarizing film may contain one or more kinds of dichroic dyes (1) and two or more kinds of dichroic dyes (2), but the composition for forming a polarizing film is also Two or more kinds of dichroic dyes (1) may be contained, and three or more types of dichroic dyes (2) may be contained. When two or more kinds of dichroic dyes (1) are contained, the content of the dichroic dye (1) is a total of two or more kinds of dichroic dyes (1), and three or more kinds thereof are contained. In the case of the dichroic dye (2), the content of the dichroic dye (2) is a total of three or more kinds of dichroic dyes (2).

The dichroic dye (2) can be, for example, Japanese Patent Laid-Open No. 58-38756 It is produced by a known method described in Japanese Laid-Open Patent Publication No. SHO-63-101850, and the like.

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

1-2. Polymeric liquid crystal compound

The polymerizable liquid crystal compound is a liquid crystal compound which can be polymerized in a state of being aligned, and has a polymerizable group in the molecule. The polarizing film-forming composition 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 preferably a radical polymerizable group. The radical polymerizable group means a group which participates 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 exhibiting a nematic phase (hereinafter sometimes referred to as a "nematic liquid crystal phase"), or may be a display layer phase The liquid crystal phase (hereinafter sometimes referred to as "layered liquid crystal phase") may be a liquid crystal phase of a nematic liquid crystal phase or a smectic liquid crystal phase, and preferably at least a liquid crystal phase. A polymeric smectic liquid crystal compound. The composition for forming a polarizing film comprising a polymerizable smectic liquid crystal compound can obtain a neutral hue property and a high polarizing property by interaction with the dichroic dye (1) and the dichroic dye (2). 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. Here, the high-order smectic liquid crystal phase is a layer B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic phase I phase, and a smectic column. The J phase, the smectic K phase, and the smectic L phase, more preferably a smectic B phase, a smectic F phase, and a smectic phase I phase.

When the smectic liquid crystal phase exhibited by the polymerizable liquid crystal compound is such a high-order smectic liquid crystal phase, the present polarizing film having a higher degree of alignment can be produced. Further, in the X-ray diffraction measurement of the present polarizing film produced by the high-order smectic liquid crystal phase having a high degree of alignment, a Böhler wave peak derived from a hexatic phase or a liquid crystal equivalent high-order structure can be obtained. Place The Bühler wave peak is a peak of a periodic structure from the molecular alignment, and the polarizing film forming composition of the present invention can obtain a polarizing film having a periodic interval of 3.0 to 5.0 Å.

For example, it can be confirmed whether or not the polymerizable liquid crystal compound contained in the composition for forming a polarizing film exhibits a nematic liquid crystal phase or a smectic liquid crystal phase. After preparing a suitable substrate and applying a composition for forming a polarizing film on the substrate to form a coating film, heat treatment or reduced pressure treatment is carried out without polymerizing the polymerizable liquid crystal compound, thereby removing the coating. The solvent contained in the film. Then, by using a texture observation by a polarizing microscope, an X-ray diffraction measurement, or a differential scanning calorimetry, the coating film formed on the substrate is heated to an isotropic phase temperature and gradually cooled. The liquid crystal phase is inspected. In the inspection, for example, a polymerizable liquid crystal compound which exhibits a nematic liquid crystal phase by cooling and which exhibits a smectic liquid crystal phase by further cooling is preferably used. In the nematic liquid crystal phase and the smectic liquid crystal phase, for example, it is confirmed that the polymerizable liquid crystal compound and the dichroic dye are not phase-separated by surface observation using various microscopes or by measurement of scattering by a haze meter.

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

The polymerizable liquid crystal composition is preferably a compound represented by the formula (4) (hereinafter sometimes referred to as "compound (4)").

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 each independently represent a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. Wherein at least one of X ¹ , X ² and X ³ is a 1,4-phenylene group which may have a substituent. The -CH ₂ - constituting the cyclohexane-1,4-diyl group which may have a substituent may be substituted with -O-, -S- or -NR-. R is an alkyl group having 1 to 6 carbon atoms or a phenyl group.

Y ¹ and Y ² independently of each other represent -CH ₂ CH ₂ -, -CH ₂ O-, -COO-, -OCOO-, a single bond, -N=N-, -CR ^a =CR ^b -, -C≡C -or-CR ^a =N-. R ^a and R ^b independently of each other represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

U ¹ represents a hydrogen atom or a polymerizable group.

U ² represents a polymerizable group.

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

V ¹ and V ² independently of each other 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. The cyclohexane-1,4-diyl group which may have a substituent is preferably a trans-cyclohexane-1,4-diyl group which may have a substituent, and a trans-cyclohexane-1,4 which may have a substituent. - The second base is preferably unsubstituted.

The 1,4-phenylene group which may have a substituent or the cyclohexane-1,4-diyl which may have a substituent may have a substituent, and examples thereof include a carbon number such as a methyl group, an ethyl group and a butyl group. An alkyl group of 1 to 4; a cyano group; a halogen atom;

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 all polymerizable groups, and more preferably all of them are photopolymerizable groups. The photopolymerizable group refers to a group which can participate in a polymerization reaction by an active 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 under lower temperature conditions.

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

Examples of the alkanediyl group having 1 to 20 carbon atoms in the alkanediyl group having 1 to 20 carbon atoms which may have a substituent represented by V ¹ and V ² include a methylene group, an exoethyl group, and a 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 and the like. V ¹ and V ^{2 are} preferably an alkanediyl group having 2 to 12 carbon atoms, more preferably an alkanediyl group having 6 to 12 carbon atoms.

Examples of the substituent which the alkanediyl group having 1 to 20 carbon atoms which may have a substituent may have a cyano group and a halogen atom, and the alkanediyl group is preferably unsubstituted, more preferably unsubstituted and straight. Chain-like alkanediyl.

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

The compound (4) may, for example, be a compound represented by the formula (4-1) to the formula (4-43). In the case where the specific example of the compound (4) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans form.

The polymerizable liquid crystal compound can be used alone or in combination of two or more kinds for the composition for forming a polarizing film. Moreover, when mixing two or more types, it is preferable that at least 1 type is compound (4). When mixing two kinds of polymerizable liquid crystal compounds, the mixing ratio is usually 1:99 to 50:50. Good for 5:95~50:50, better 10:90~50:50.

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

The content ratio of the polymerizable liquid crystal compound in the composition for forming a polarizing film is preferably from 50 to 99.9% by mass, more preferably from 80 to 99.9% by mass, based on the solid content of the composition for forming a polarizing film. When the content ratio of the polymerizable liquid crystal compound is in the above range, the alignment property of the polymerizable liquid crystal compound tends to be improved, which is preferable. Here, the solid content component refers to a total amount of components obtained by removing a volatile component 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 which completely dissolves the polymerizable liquid crystal compound and the dichroic dye. Moreover, it is preferably a solvent which is inert to the polymerization reaction of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film.

Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, and ethylene Ester solvent 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 Iddin Ketone solvents such as ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chloroform and chlorine a chlorine-containing solvent such as benzene; These solvents may be used singly or in combination of plural kinds.

The content of the solvent is preferably from 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 composition for forming a polarizing film is preferably from 2 to 50% by mass. When the solid content component is 2% by mass or more, it is preferred to obtain a thin-type polarizing film which is one of the objects of the present invention. In addition, when the content of the solid content is 50% by mass or less, the viscosity of the composition for forming a polarizing film is lowered, so that the thickness of the polarizing film is substantially uniform, whereby the polarizing film tends to be less likely to be uneven. good. Moreover, such a solid content can be determined in consideration of the thickness of the polarizing film.

1-4. Other additives

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

1-4-1. Polymerization aid

The composition for forming a polarizing film preferably contains a polymerization initiator. The polymerization initiator is a compound which can initiate polymerization of a polymerizable liquid crystal compound. The polymerization initiator is preferably a photopolymerization initiator in terms of starting the polymerization under low temperature conditions. Specifically, a compound which generates an active radical or an acid by the action of light can be used as a photopolymerization initiator. Among the photopolymerization initiators, those which generate active radicals by the action of light are more preferred.

Examples of the polymerization initiator include a benzoin compound, a diphenyl ketone compound, a phenylalkyl ketone compound, a decyl phosphine oxide compound, and the like. Compounds, strontium salts and strontium 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 o-benzamide. Methyl ester, 4-phenyldiphenyl ketone, 4-benzylidene-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl) Diphenyl ketone and 2,4,6-trimethyldiphenyl ketone and the like.

Examples of the phenylalkyl ketone compound include diethoxyacetophenone and 2-methyl-2- Lolinyl-1-(4-methylthienyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4- Polinylphenyl)butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane- 1-ketone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2- An oligomer of methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one or the like.

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

As three The compound may, for example, be 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-tri , 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-three 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-three , 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)vinyl]-1,3,5-three , 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl]-1,3,5-three , 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)vinyl]-1,3,5-three And 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)vinyl]-1,3,5-tri Wait.

A polymerization initiator can also be used by a commercial one. As a commercially available polymerization initiator, "Irgacure 907", "Irgacure 184", "Irgacure 651", "Irgacure 819", "Irgacure 250", "Irgacure 369" (Ciba-Japan Co., Ltd.); "Seikuol BZ", " Seikuol Z", "Seikuol BEE" (Seiko Chemical Co., Ltd.); "kayacure BP100" (Nippon Chemical Co., Ltd.); "kayacure UVI-6992" (manufactured by Dow); "Adeka Optomer SP-152", Adeka Optomer SP-170" (ADEKA Co., Ltd.); "TAZ-A", "TAZ-PP" (Nihon Siber Hegner); and "TAZ-104" (Sanwa Chemical).

When the composition for forming a polarizing film contains a polymerization initiator, the content thereof may be The content of the polymerizable liquid crystal compound to be contained in the composition for forming a polarizing film and the amount thereof are appropriately adjusted, and the content of the polymerization initiator is preferably 0.1 to 30 parts by mass based on 100 parts by mass of the total of the polymerizable liquid crystal compound. It is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass. When the content of the polymerizable initiator is within this range, the polymerization can be carried out without disturbing the alignment of the polymerizable liquid crystal compound, which is preferable.

1-4-2. Photosensitizer

When the composition for forming a polarizing film contains a photopolymerization initiator, the composition for forming a polarizing film may further contain a photosensitizer. As the photosensitizer, for example, Ketone and 9-oxosulfur Wait Ketone compounds (for example, 2,4-diethyl 9-oxosulfur 2-isopropyl 9-oxosulfur And other compounds such as anthracene and alkoxy-containing anthracene (e.g., dibutoxyanthracene); And red fluorene and the like.

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

1-4-3. Polymerization inhibitor

In order to stably carry out the polymerization reaction of the polymerizable liquid crystal compound, the composition for forming a polarizing film may further contain a polymerization inhibitor. The degree of progress of the polymerization reaction of the polymerizable liquid crystal compound can be controlled by the polymerization inhibitor.

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

When the polymerization inhibitor is contained in the composition for forming a polarizing film, the content thereof is The amount of the polymerizable liquid crystal compound to be used, the amount of the photosensitizer, and the like can be appropriately adjusted, and it is usually 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. More preferably, it is 0.5 to 8 parts by mass.

When the content of the polymerization inhibitor is in the above range, polymerization can be carried out without disturbing the alignment of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film, which is preferable.

1-4-4. Leveling agent

The composition for forming a polarizing film preferably contains a leveling agent. The leveling agent is a function of adjusting the fluidity of the composition for forming a polarizing film, and the coating film obtained by applying the composition for forming a polarizing film is more flat, and a surfactant or the like is exemplified. Preferred leveling agents 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.

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

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

When the leveling agent is contained in the composition for forming a polarizing film, the content thereof is usually 0.3 parts by mass or more and 5 parts by mass or less, preferably 0.5 parts by mass or more, based on 100 parts by mass of the content of the polymerizable liquid crystal compound. The following. When the content of the leveling agent is within the above range, the polymerizable liquid crystal compound tends to be horizontally aligned, and the obtained polarizing film tends to be smoother, which is preferable. When the content of the leveling agent relative to the polymerizable liquid crystal compound exceeds the above range, the obtained polarizing film tends to be uneven. Further, the polarizing film-forming composition may contain two or more kinds of leveling agents.

2. The method for forming the polarizing film

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

2-1. Transparent substrate

The transparent substrate is a substrate having transparency to a degree that transmits light, particularly visible light. The term "transparency" refers to a characteristic that the transmittance of light in the wavelength range of 380 to 780 nm is 80% or more. Specifically, examples of the transparent substrate include a glass substrate and a plastic substrate, and a plastic substrate is preferable. Examples of the plastic constituting the plastic substrate include polyethylene, polypropylene, and Polyolefin such as olefin polymer; cyclic olefin resin; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; cellulose triacetate, cellulose diacetate and propionic acid acetate Cellulose esters such as cellulose; polyethylene naphthalate; polycarbonate; polyfluorene; polyether oxime; polyether ketone; polyphenylene sulfide and polyphenylene ether. Among them, cellulose ester, cyclic olefin resin, polyethylene terephthalate or polymethacrylate is particularly preferable in terms of being easily obtained from the market or excellent in transparency. When the polarizing film is produced by using such a transparent substrate, it can be easily handled when transporting or storing the transparent substrate without causing breakage such as cracking, or the transparent substrate can be attached thereto. Support the substrate and the like. Further, a case will be described later in which a phase difference is imparted to the plastic substrate when the circular polarizing plate is produced from the polarizing film. In this case, it is sufficient to impart phase difference to the plastic substrate by stretching treatment or the like.

In the case where phase difference is imparted to the plastic substrate, it is preferable to control the phase difference value, and it is preferably a plastic substrate containing a cellulose ester or a cyclic olefin resin.

At least a part of the hydroxyl group contained in the cellulose ester cellulose is obtained by acetate. A cellulose ester film containing such a cellulose ester can be easily obtained from the market. Examples of the commercially available cellulose triacetate film 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 as needed to impart phase difference. Further, the surface of the prepared transparent substrate may be subjected to a surface treatment such as an antiglare treatment, a hard coating treatment, an antistatic treatment or an antireflection treatment, and then used as a transparent substrate.

As described above, the plastic substrate is imparted with phase difference by a method such as stretching the plastic substrate. The plastic substrate containing the thermoplastic resin can be subjected to elongation treatment, and is more preferably a plastic substrate containing a cyclic olefin resin in terms of easy control of phase difference. The term "cyclic olefin resin" includes, for example, a drop Alkene or polycyclic drop In the case of a polymer or a copolymer of a cyclic olefin such as an olefinic monomer, the cyclic olefin resin may partially contain a ring-opening portion. Further, it may be a hydrogenated cyclic olefin resin containing an open ring portion. Further, the cyclic olefin resin may be, for example, a cyclic olefin, a chain olefin or an alkylated aromatic compound (styrene, etc.) in terms of not significantly impairing transparency or not significantly increasing hygroscopicity. And other copolymers. Further, the cyclic olefin 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 or propylene, and the vinylated aromatic compound is styrene. Α-methyl styrene and alkyl-substituted styrene and the like. In such a copolymer, the content ratio of the structural unit derived from the cyclic olefin is 50 mol% or less, for example, about 15 to 50 mol%, based on the total structural unit of the cyclic olefin resin. In the case where the cyclic olefin resin is a terpolymer obtained from a cyclic olefin, a chain olefin, or an ethylene compound, the content ratio of the structural unit derived from a chain olefin is, for example, 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 an advantage of being able to relatively reduce the amount of use of a high-priced cyclic olefin when the cyclic olefin-based resin is produced.

The cyclic olefin resin can be easily obtained from the market. As a commercially available cyclic olefin resin, "Topas" [Ticona Co., Ltd.]; "Arton" [JSR Co., Ltd.]; "ZEONOR" and "ZEONEX" [Japan Zeon Co., Ltd.]; "APEL [Manufactured by Mitsui Chemicals Co., Ltd.]. For example, a cyclic olefin-based resin can be formed into a film (cyclic olefin-based resin film) by a known film forming method such as a solvent casting method or a melt extrusion method. Further, a cyclic olefin-based resin film commercially available in the form of a film may also be used. Examples of the commercially available cyclic olefin-based resin film include "S-SINA" and "SCA40" [Ji Shui Chemical Industry Co., Ltd.]; "Zeonor Film" [Optes Co., Ltd.]; "Arton Film" [JSR Co., Ltd.] and so on.

Next, a method of imparting phase difference to a plastic substrate will be described. The plastic substrate can impart phase difference by a known stretching method. For example, a reel (rolling body) in which a plastic substrate is wound around a roll is prepared, and a plastic substrate is continuously taken out from the winding body, and the rolled plastic substrate is transferred to a heating furnace. The set temperature of the heating furnace is set to the range of the glass transition temperature of the plastic substrate (°C) to [glass transition temperature +100] (°C), preferably set to the vicinity of the glass transition temperature (°C)~[glass transition temperature +50] (°C) range. In the heating furnace, when extending in the direction perpendicular to the traveling direction of the plastic substrate or in the direction orthogonal to the traveling direction, the conveying direction or the tension is adjusted and the inclination is applied to an arbitrary angle to perform the uniaxial or biaxial heat stretching treatment. The magnification of the stretching is usually in the range of about 1.1 to 6 times, preferably in the range of about 1.1 to 3.5 times. Further, the method of extending in the oblique direction is not particularly limited as long as it can continuously tilt the desired angle in the alignment axial direction, and a known extension method can be employed. this For example, the method described in Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei.

The thickness of the transparent substrate is preferably thin in terms of the weight of the practical operation and the sufficient transparency, but if it is too thin, the strength tends to be lowered and the workability tends to be poor. The appropriate thickness of the glass substrate is, for example, about 100 to 3000 μm, preferably about 100 to 1000 μm. The appropriate thickness of the plastic substrate is, for example, about 5 to 300 μm, preferably about 20 to 200 μm. The thickness of the transparent substrate in the case where the polarizing film is used as the circular polarizing plate described below, particularly in the case of a circularly polarizing plate used for mobile equipment, is preferably about 20 to 100 μm. Further, in the case where phase difference is imparted to the film by stretching, the thickness after stretching depends on the thickness or the stretching ratio before stretching.

2-2. Orientation film

Preferably, an alignment film is formed on the substrate used in the production of the polarizing film. In this case, the composition for forming a polarizing film is applied onto the alignment film. Therefore, the alignment film preferably has solvent resistance to such an extent that it is not dissolved by coating or the like of the composition for forming a polarizing film. Further, it is preferable to have heat resistance for heat treatment for removing the solvent or aligning the liquid crystal. Such an alignment film can be formed of an alignment polymer.

The above-mentioned alignment polymer may, for example, be a polyamine or a gelatin having a guanamine bond in a molecule, a polyamidomine having a ruthenium bond in a molecule, and a hydrolysate thereof. Polyvinyl alcohol, alkyl modified polyvinyl alcohol, polypropylene decylamine, poly A polymer such as azole, polyethylenimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid or polyacrylate. Among these, polyvinyl alcohol is preferred. These alignment polymers which form an alignment film may be used singly or in combination 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 (solution containing an alignment polymer) dissolved in a solvent and coating the substrate. The solvent may, for example, be water; an alcohol solvent such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, methyl stilbene, butyl sarbuta or propylene glycol monomethyl ether; Ester ester, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate and ethyl lactate; ester solvent; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone Ketone solvents such as methyl amyl ketone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; tetrahydrofuran and dimethyl An ether solvent such as oxyethane; a chlorine-substituted hydrocarbon solvent such as chloroform or chlorobenzene; These organic solvents may be used singly or in combination of plural kinds.

Further, as the alignment polymer composition for forming the alignment film, a commercially available alignment film material can be used as it is. As a commercially available alignment film material, Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) or Optomer (registered trademark, manufactured by JSR Co., Ltd.) or the like can be cited.

The method of forming the alignment film on the substrate may, for example, be a method in which the above-mentioned alignment polymer composition or a commercially available alignment film material is applied to a substrate and annealed. The thickness of the alignment film obtained in this manner is usually in the range of 10 nm to 10000 nm, preferably in the range of 10 nm to 1000 nm.

It is preferable to perform rubbing (friction method) as needed to impart an alignment restricting force to the above alignment film. By imparting an alignment limiting force, the polymerizable liquid crystal compound can be aligned in a desired direction.

As a method of imparting the alignment regulating force by the rubbing method, for example, a method of preparing a laminated body in which a coating film for forming an alignment film is formed on a substrate is prepared by preparing a rubbing roll that is wound with a rubbing cloth and rotating The coating film for forming an alignment film is brought into contact with the rubbing roller that is rotating on the mounting table and transported to the rubbing roller that is rotating.

Further, a so-called photoalignment film can also be used. The photo-alignment film is a composition obtained by coating a polymer containing a photoreactive group or a monomer and a solvent (hereinafter sometimes referred to as "photo-alignment layer-forming composition") on a substrate. The polarizing film (preferably polarized UV (ultraviolet)) is irradiated to give an alignment film having an alignment regulating force. The photoreactive group refers to a group which generates liquid crystal alignment energy by irradiation light (light irradiation). in particular, The reaction is a photoreaction which is the origin of liquid crystal alignment energy, such as alignment induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction of a molecule generated by irradiation of light. Among the photoreactive groups, in terms of the aligning liquid crystal state at the time of forming the polarizing film, it is preferred to generate a dimerization reaction or a photocrosslinking reaction. The photoreactive group which can produce the above reaction is preferably an unsaturated bond, especially a double bond, and more preferably has a carbon-carbon double bond (C=C bond) and a carbon-nitrogen double bond (C=N). A group of at least one of a group consisting of a 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 decyl group, a carbazolyl group, an oxazolyl group, a chalcone group, and a cinnamyl group. Examples of the photoreactive group having a C=N bond include a group having a structure such as an aromatic Schiff base and an aromatic fluorene. Examples of the photoreactive group having a N=N bond include an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a bisazo group, and a fluorenyl group, or an oxyazobenzene group. Basic structure. Examples of the photoreactive group having a C=O bond include a diphenylketone group, a coumarin group, an anthracenyl group, and a maleimide group. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group or a halogenated alkyl group.

Among them, a photoreactive group capable of generating a photodimerization reaction is preferred, and the amount of polarized light required for cinnamyl sulfhydryl and chalcone groups due to photo-alignment is relatively small, and it is easy to obtain thermal stability or excellent stability over time. The light alignment film is preferred. In this regard, the polymer having a photoreactive group is particularly preferably one having a cinnabar base which is a cinnamic acid structure at the end portion of the side chain of the polymer.

The solvent of the composition for forming a photo-alignment layer is preferably a polymer or a monomer in which a photoreactive group is dissolved. Examples of the solvent include the above-mentioned solvent for the alignment polymer composition.

The concentration of the photoreactive group-containing polymer or monomer relative to the photo-alignment layer-forming composition can be appropriately adjusted depending on the kind of the photoreactive group-containing polymer or monomer or the thickness of the photo-alignment film to be produced. , expressed as a solid content concentration, preferably set to It is 0.2% by mass or less, and particularly preferably in the range of 0.3 to 10% by mass. Further, the composition for forming an alignment layer may contain a polymer material such as polyvinyl alcohol or polyimine or a photosensitizer in a range that does not significantly impair the characteristics of the photo-alignment film.

As a method of applying the composition for forming an alignment polymer or a composition for photoalignment layer to a substrate, a spin coating method, an extrusion method, a gravure coating method, a die coating method, or a bar coating method can be employed. A known method such as a coating method such as an applicator method or a printing method such as a soft plate method. Further, in the case where the polarizing film is produced by the following continuous production method in the form of a roll to roll, the coating method is usually printed by gravure coating, die coating or soft printing. law.

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

2-3. Method for manufacturing the polarizing film

A coating film forming composition is applied onto the alignment film formed on the substrate or the substrate to obtain a coating film. The method of applying the composition for forming a polarizing film is, for example, the same method as the method of applying the composition for forming an alignment polymer or a photoreactive layer to a substrate.

Then, the solvent is dried and removed under the condition that the polymerizable liquid crystal compound contained in the coating film is not polymerized, thereby forming a dried film. Examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method, and a vacuum drying method.

Then, in a preferred embodiment, the liquid crystal state of the polymerizable liquid crystal composition contained in the dried film is temporarily set to a nematic liquid crystal, and then the nematic liquid crystal phase is transferred into a smectic liquid crystal phase.

In order to form the smectic liquid crystal phase via the nematic liquid crystal phase, for example, a method may be employed in which the polymerizable liquid crystal compound contained in the dried film is displayed at a temperature higher than the temperature of the nematic liquid crystal phase, and then cooled to the polymerization. The liquid crystal compound shows the temperature of the smectic liquid crystal phase.

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

Next, the polymerization step of the polymerizable liquid crystal compound will be described. Here, the method of forming a polarizing film forming composition contains a photopolymerization initiator, and the liquid crystal state of the polymerizable liquid crystal compound in the dried film is a smectic liquid crystal phase, and then the film is maintained. The polymerizable liquid crystal compound is photopolymerized in a liquid crystal state of the smectic liquid crystal phase.

In the photopolymerization, the light to be irradiated to the dried film may be based on the type of the photopolymerization initiator contained in the dried film or the type of the polymerizable liquid crystal compound (especially the polymerizable liquid crystal compound). The type of the polymerizable group and the amount thereof are suitably carried out by light or an active electron beam selected from the group consisting of visible light, ultraviolet light, and laser light. Among these, it is preferred to control the progress of the polymerization reaction, or to use a device widely used as a photopolymerization in the field, preferably ultraviolet light. Therefore, it is preferred to select the type of the polymerizable liquid crystal compound or the photopolymerization initiator contained in the composition for forming a polarizing film by photopolymerization by ultraviolet light. Further, in the polymerization, in addition to ultraviolet light irradiation, the polymerization temperature may be controlled by cooling the dried film by an appropriate cooling method. By using such a cooling method, it is also advantageous in that if the polymerization of the polymerizable liquid crystal compound can be carried out at a lower temperature, even if the substrate is used in a relatively low heat resistance, the polarizing film can be appropriately formed. Further, the patterned local polarizing film can also be obtained by masking or developing during photopolymerization.

By carrying out the above photopolymerization, the polymerizable liquid crystal compound is polymerized while maintaining a nematic liquid crystal phase, a smectic liquid crystal phase, preferably a higher order smectic liquid crystal phase as exemplified, thereby forming the present polarizing film. . The polymerizable liquid crystal compound maintains the smectic liquid crystal phase The present polarizing film obtained by polymerization in a state has a polarizing property as compared with a polarizing film obtained by polymerizing a polymerizable liquid crystal compound or the like in a state in which a liquid crystal state of a nematic liquid crystal phase is maintained. Higher advantage. Further, it has an advantage of being superior in strength as compared with a case where only a liquid-colored dichroic dye is applied.

The thickness of the present polarizing film thus formed is preferably in the range of 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less. Therefore, the thickness of the coating film for forming a polarizing film can be determined in consideration of the thickness of the obtained polarizing film. Further, the thickness of the polarizing film is determined by measurement by an interference film thickness meter, a laser microscope or a stylus film thickness meter.

Further, as described above, the thus-formed polarizing film is preferably one which can obtain a Bühler wave in the X-ray diffraction measurement. As the present polarizing film in which the Böhler wave peak is obtained, for example, the present polarizing film which exhibits a diffraction peak from a hexagonal phase or a liquid crystal phase can be cited.

Further, the present polarizing film thus produced is excellent in the neutral color phase property. Here, the polarizing film excellent in neutral hue is a color coordinate a ^* value and a b ^* value in the L ^* a ^* b ^* (Lab) color system satisfying the following formulas (1F) and (2F). Relationship. Furthermore, the color coordinates a ^* value and b ^* value can be obtained, for example, by the measurement method described in the examples of the present application.

-3 ≦ chromaticity a ^* ≦ 3 (1F)

-3 ≦ 度 b ^* ≦ 3 (2F)

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

Further, in the hue of the polarizing film, the two polarizing films are superposed 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". ^In the case of ^* ", it is preferable that each of the orthogonal a ^* and the orthogonal b ^* satisfy the relationship between the following formula (1F') and the formula (2F'). In a display device having a polarizing film, the orthogonal a ^* and the orthogonal b ^* indicate whether or not 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 coloration can be obtained.

-3≦orthogonal a ^* ≦3 (1F')

-3≦orthogonal b ^* ≦3 (2F')

3. The continuous manufacturing method of the polarizing film

As described above, the outline of the method for producing the polarizing film has been described. However, when the polarizing film is commercially produced, a method of continuously producing the polarizing film is required. Such a continuous manufacturing method is achieved by a roll-to-roll form, and is sometimes referred to as "this manufacturing method." In the present manufacturing method, the case where the substrate is a transparent substrate will be mainly described. When the substrate is a transparent substrate, the final obtained is a polarizing element having a transparent substrate and a polarizing film (hereinafter sometimes referred to as "the present polarizing element").

The manufacturing method includes, for example, a step of preparing a first reel in which a transparent substrate is wound on a first core, a step of continuously feeding the transparent substrate from the first reel, and continuously forming on the transparent substrate. a step of aligning the film; a step of continuously applying the composition for forming a polarizing film on the alignment layer; and drying the applied composition for forming a polarizing film by polymerizing the liquid crystalline compound without polymerization, and the alignment film a step of continuously forming a dry film; the polymerizable liquid crystal compound contained in the dried film is a nematic liquid crystal phase, preferably a smectic liquid crystal phase, and is maintained in a state of the smectic liquid crystal phase The step of polymerizing the polymerizable liquid crystal compound to obtain a polarizing film continuously to form a polarizing element, and winding the continuously obtained polarizing element on the second core to obtain a second roll. Here, referring to Fig. 1, the present manufacturing method will be described with respect to the case where a photo-alignment film is used as an alignment film in particular.

The first reel 210 in which the transparent substrate is wound around the first core 210A can be easily obtained from the market, for example. As a transparent substrate which can be obtained from the market in the form of such a roll, the transparent base material exemplified includes cellulose ester, cyclic olefin resin, and polyparaphenylene. A film of ethylene formate, polycarbonate or polymethacrylate, and the like. In addition, when the polarizing film is used as a circularly polarizing plate, a transparent substrate having phase difference in advance can be easily obtained from the market, and examples thereof include a retardation film containing a cellulose ester or a cyclic olefin resin. .

Then, the transparent substrate is taken up from the first reel 210. The method of winding out the transparent substrate is performed by providing an appropriate rotation mechanism to the winding core 210A of the first reel 210, and rotating the first reel 210 by the rotation mechanism. Further, a suitable auxiliary roller 300 may be provided in the direction in which the transparent substrate is conveyed from the first reel 210, and the transparent substrate may be wound up by the rotation mechanism of the auxiliary roller 300. Further, a configuration may be adopted in which the first winding core 210A and the auxiliary roller 300 are provided with a rotating mechanism, and a transparent substrate is wound while applying a moderate tension to the transparent substrate.

When the transparent substrate wound out from the first reel 210 is passed through the coating device 211A, the composition for forming a photo-alignment layer is applied onto the surface of the coating device 211A. As described above, in order to continuously apply the composition for forming a photoalignment layer as described above, a printing method such as a gravure coating method, a die coating method, or a soft plate method is carried out by the coating device 211A.

The transparent substrate that has passed through the coating device 211A is transferred to the drying furnace 212A, and is heated by the drying furnace 212A to continuously form the first dried coating on the transparent substrate. As the drying furnace 212A, for example, a hot air drying oven or the like can be used. The set temperature of the drying furnace 212A can be determined according to the type of the solvent contained in the composition for forming an optical alignment layer applied by the coating device 211A. Further, the drying furnace 212A may be a drying furnace in which the plurality of regions are divided into a plurality of regions and the set temperatures of the plurality of regions are different, and a plurality of drying furnaces may be arranged in series, and each of the drying furnaces may be arranged Set the drying furnace in the form of different temperatures.

The first dry film which is continuously formed by the heating furnace 212A is then irradiated with polarized UV on the surface of the first dry film side or the surface of the transparent substrate side by the polarized UV irradiation device 213A, whereby the first dry cover is applied. The film forms a (light) alignment film. At this time, the direction of the transfer direction D1 of the transparent substrate and the alignment direction D2 of the formed photo-alignment film may be made cross. Fig. 2 is a schematic view showing the relationship between the alignment direction D2 of the photo-alignment film formed after the polarized UV irradiation and the transport direction D1 of the transparent substrate. In other words, 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 layered body after passing through the polarized UV irradiation device 213A, the angle formed by the film is substantially 45°.

The transparent substrate (first laminate) in which the photo-alignment film is continuously formed is coated with the composition for forming a polarizing film on the photo-alignment film by the coating device 211B, and then passed through the drying furnace 212B. The polymerizable liquid crystal compound contained in the composition for forming a polarizing film is formed in the drying furnace 212B to form a nematic liquid crystal phase, preferably a smectic liquid crystal phase, thereby forming a second dry film.

In the transparent substrate of the drying oven 212B, the solvent contained in the composition for forming a polarizing film is sufficiently removed, and the polymerizable liquid crystal compound in the second dried film retains the nematic liquid crystal phase, preferably The liquid crystal state of the smectic liquid crystal phase is transferred to the light irradiation device 213B. By the light irradiation of the light irradiation device 213B, the polymerizable liquid crystal compound is photopolymerized while maintaining the liquid crystal state, and the present polarizing film is continuously formed on the alignment film to obtain the present polarizing element.

The present polarizing film thus formed is wound around the second core 220A in a form of a laminate including a transparent substrate and an alignment film, and the second roll 220 is obtained. When the second reel is obtained by winding the formed polarizing film, it is also possible to use a co-roll using a suitable spacer.

Thus, the transparent substrate is sequentially passed through the first reel/coating device 211A/drying furnace 212A/polarized UV irradiation device 213A/coating device 211B/drying furnace 212B/light irradiation device 213B on a transparent substrate. The present polarizing film is continuously formed on the light alignment film to manufacture the polarizing element.

Further, although the present manufacturing method shown in Fig. 1 shows a method of continuous production from a transparent substrate to the present polarizing film, for example, the present polarizing element can be manufactured by: passing the transparent substrate sequentially 1st reel / coating device 211A / drying oven 212A / polarization The first layered product continuously formed by the UV irradiation device 213A is wound around the core, and the first layered body is produced in the form of a roll, and the first layered body is taken up from the roll, and the first layered body is wound up. The laminated body sequentially passes through the coating device 211B/drying furnace 212B/light irradiation device 213B.

The present polarizing element obtained by the present production method has a shape of a film and a strip shape. When the present polarizing film is used in a liquid crystal display device or the like described below, it is used for cutting to a desired size depending on the size of the liquid crystal display device or the like.

In the above, the configuration and manufacturing method of the present polarizing element are mainly centered on the form of the laminated body of the transparent substrate/light alignment film/the present polarizing film, but the light alignment film may be peeled off from the present polarizing element. Or the transparent substrate to obtain the polarizing film in the form of a single layer. Further, a layer or a film other than the transparent substrate/photoalignment film/the present polarizing film may be laminated on the polarizing element. As the layers and films, as described above, the polarizing film may further have a retardation film, and may further have an antireflection layer or a brightness enhancement film.

Further, a transparent polarizing substrate itself may be used as a retardation film to form a circularly polarizing plate or an elliptically polarizing plate in the form of a retardation film/optical alignment film/the present polarizing film. For example, when a uniaxially extending quarter-wave plate is used as the retardation film, the roller-to-roller can be set by setting the irradiation direction of the polarized UV in a manner of substantially 45° with respect to the conveying direction of the transparent substrate. Form a circular polarizer. The quarter-wavelength plate used in the production of the circularly polarizing plate in this manner preferably has a characteristic that the in-plane retardation value with respect to visible light becomes smaller as the wavelength becomes shorter.

Further, a linear polarizing plate roll whose offset is set at an angle between the slow axis and the absorption axis of the polarizing film may be formed by using a 1⁄2 wavelength plate as a retardation film, and may be formed on the surface on which the polarizing film is formed. The opposite side further forms a quarter-wavelength plate to form a wide-band circular polarizing plate.

4. Use of the polarizing film

The polarizing film can be used in various display devices. A display device is a device having a display element and includes a light-emitting element or a light-emitting device as a light-emitting source. 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 elements), plasma display device, projection display device (eg gate A light-emitting valve (GLV) display device, a display device having a digital micro-mirror device (DMD), a piezoelectric ceramic display, or the like. In the liquid crystal display device, a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, an intuitive liquid crystal display device, and a projection type liquid crystal display device are included. The display device may be a display device for displaying a two-dimensional image or a stereoscopic display device for displaying a three-dimensional image.

The present polarizing film is particularly useful 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 configuration 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 the two substrates 14a and 14b.

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

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

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

A color filter 15 is disposed on the liquid crystal layer 17 side of the substrate 14a. The color filter 15 is disposed at a position facing the pixel electrode 22 so as to sandwich the liquid crystal layer 17, and the black matrix 20 is disposed at a position facing the boundary between the pixel electrodes. The transparent electrode 16 is disposed on the liquid crystal layer 17 side so as to cover the color filter 15 and the black matrix 20. Further, a protective layer (not shown) may be provided between the color filter 15 and the transparent electrode 16.

The thin film transistor 21 and the pixel electrode 22 are arranged in order on the liquid crystal layer 17 side of the substrate 14b. The pixel electrode 22 is disposed on the color filter 15 so as to sandwich the liquid crystal layer 17 The position of the opposite. 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 can be made of the same material as that of the transparent substrate used in the production of the polarizing film. Moreover, the transparent substrate 1 of the present polarizing film can also serve as the substrate 14a and the substrate 14b. In the case where it is necessary to heat to a high temperature when manufacturing the color filter 15 or the thin film transistor 21 formed on the substrate, a glass substrate or a quartz substrate is preferable.

The thin film transistor can be most suitably used depending on the material of the substrate 14b. Examples of the thin film transistor 21 include a high-temperature polycrystalline germanium transistor formed on a quartz substrate, a low-temperature polycrystalline germanium transistor formed on a glass substrate, and an amorphous germanium transistor formed on a glass substrate or a plastic substrate. In order to further reduce the size of the liquid crystal display device, 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 14a and the substrate 14b constant, the spacer 23 is disposed in the liquid crystal layer 17. Further, although FIG. 3 is illustrated as a columnar spacer, the spacer is not limited to the 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 constant.

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

In the substrate 14a and the substrate 14b sandwiching the liquid crystal layer 17, the polarizing elements 12a and 12b are provided on the outer side of the substrate 14b, and at least one of the polarizing elements is used.

Further, it is preferable to laminate a retardation layer (for example, a quarter-wave plate or an optical compensation film) 13a and 13b. In the polarizing elements 12a and 12b, by arranging the present 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 disposed, and the transparent substrate may be a retardation film and include the present invention. 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 be omitted. A polarizing film may be further provided on the light exit side (outer side) 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 (on the outer side of the polarizing film in which the polarizing film is further provided).

As described above, the polarizing element 12a or 12b of the 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 effect of reducing the thickness of the liquid crystal display device 10 can be achieved.

In the case where the present polarizing element is used for the polarizing element 12a or 12b, the order of lamination is not particularly limited. This will be described with reference to an enlarged view of portions A and B surrounded by a broken line in FIG.

Figure 4 is an enlarged schematic cross-sectional view of a portion A of Figure 3. (A1) of FIG. 4 shows a case where the polarizing element 100 is used as the polarizing element 12a, and the polarizing film 3, the optical alignment film 2, and the transparent substrate are disposed in order from the phase difference layer 13a side. The situation of 1. Moreover, (A2) of FIG. 4 shows a case where the transparent base material 1, the optical alignment film 2, and the present polarizing film 3 are provided in order from the phase difference layer 13a side.

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

A backlight unit 19 as a light source is disposed 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 device, a cold cathode tube, a hot cathode tube, a light emitting diode (LED), a laser light source, and a mercury lamp. Further, the type of the polarizing film can be selected in accordance with the characteristics of such a light source.

When 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 the light guide body, and the forward path is changed by the reflection plate, and is diffused by the diffusion sheet. . The diffused light is incident from the backlight unit 19 to the polarizing element 12b by adjusting the viewing angle adjusting sheet so as to have a desired directivity.

Among the incident light that is not polarized, only a certain linearly polarized light is transmitted through the polarizing element 12b of the liquid crystal panel. The 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 is changed, thereby performing the luminance of the light emitted from the liquid crystal display device 10. control. When the liquid crystal layer 17 is in an alignment state in which the 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 to reach the polarizing element 12a, and the liquid crystal display The device displays the color determined by the color filter in the brightest manner.

On the other hand, when the liquid crystal layer 17 is in an alignment state in which the polarized light is directly transmitted, the light transmitted through the liquid crystal layer 17, the transparent electrode 16, and the color filter 15 is absorbed by the polarizing element 12a. Thereby, the pixel displays black. In the alignment state between the 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 that the pixel displays the 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 polarizing film of the polarizing element and further laminated with a quarter-wave plate (circular polarizing plate). At this time, the pixel electrode 22 has a transmissive portion formed of a transparent material and a reflecting portion formed of a material that reflects light, and the transmissive portion displays an image in the same manner as the transmissive liquid crystal display device. On the other hand, in the reflection portion, the external light is incident on the liquid crystal display device, and the circularly polarized light that has passed through the polarizing film passes through the liquid crystal layer 17 by the polarizing film and the quarter-wave plate, and is applied by the pixel electrode 22 Reflected for display.

Next, the present EL display device 30 using the present polarizing film will be described with reference to FIG. In the case where the present polarizing film is used in the present EL display device, it is preferable to use the polarizing film as a circular polarizing plate (hereinafter sometimes referred to as "the present polarizing plate"). There are two embodiments of the circular polarizing plate. Therefore, two embodiments of the present circular polarizing plate will be described with reference to FIG. 7 before explaining the configuration of the EL display device 30 and the like.

Fig. 7(A) is a schematic view showing the first embodiment of the circular polarizing plate 110. In the first embodiment, the present polarizing film 3 of the present polarizing element 100 is further provided with a circular polarizing plate 110 of a retardation layer (retardation film) 4. Fig. 7(B) is a schematic view showing a second embodiment of the circular polarizing plate 110. In the second embodiment, the transparent substrate 1 (phase difference film 4) to which phase difference is applied in advance is used for the transparent substrate 1 used in the production of the polarizing element, and the transparent substrate 1 itself has a phase. The circular polarizing plate 110 having the function of the difference layer 4.

In the second embodiment including the present polarizing film, the second polarizing plate comprising the present polarizing film is preferably a simple structure. In this case, it is preferable to use a quarter-wave plate as a transparent substrate. Further, it is preferable to use a quarter-wave plate as a transparent substrate and to satisfy the following requirements (A1) and (A2).

(A1) an angle formed by an absorption axis of the polarizing film and a retardation axis of the 1/4 wavelength plate is substantially 45°; (A2) a front retardation of the 1/4 wavelength plate measured by light having a wavelength of 550 nm The value is in the range of 100 to 150 nm.

Here, a method of manufacturing the circular polarizing plate 110 will be described. In the second embodiment of the circularly polarizing plate 110, as described above, a transparent substrate 1 having a phase difference imparted in advance, that is, a retardation film as a transparent substrate 1 can be used in the production method for producing the polarizing film 100. And manufacturing. In the first embodiment of the present invention, the retardation film 4 can be formed by laminating a retardation film on the polarizing film 3 manufactured by the present manufacturing method B. In the case where the polarizing film 100 is produced in the form of the second reel 220 by the manufacturing method B, the polarizing film 100 may be taken up from the second reel 220 and cut into a specific size. The shape of the retardation film is applied to the cut polarizing film 100, and can also be wound on the core. The third reel of the retardation film is used to continuously produce a circular polarizing plate 110 having a film shape and a long strip shape.

A method of continuously manufacturing the first embodiment of the circular polarizing plate 110 will be described with reference to Fig. 8 . The manufacturing method includes the steps of continuously winding up the polarizing element 100 from the second reel 220 and continuously winding the retardation film from the third reel 230 wound with the retardation film; a step of forming a polarizing film provided on the polarizing element 100 wound by the reel 220 and the retardation film rolled out from the third reel to form the circular polarizing plate 110; and forming the circle The step of obtaining the fourth reel 240 by winding the polarizing plate 110 on the fourth core 240A.

As described above, the manufacturing method of the first embodiment of the circular polarizing plate 110 has been described. When the polarizing film 3 and the retardation film in the polarizing element 100 are bonded, an appropriate adhesive can be used, and the adhesive can be used. The adhesive layer is formed to bond the polarizing film 3 and the retardation film.

Next, the present EL display device having the present 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 and a cathode electrode 37 as light-emitting sources on a substrate 33 on which the pixel electrodes 35 are formed. The circular polarizing plate 31 is disposed on the opposite side of the organic functional layer 36 so as to sandwich the substrate 33, and the circular polarizing plate 110 is used as the circular 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 source includes an electron transport layer, a light emitting layer, a hole transport layer, and the like. The light emitted from the organic functional layer 36 passes through the pixel electrode 35, the interlayer insulating film 34, the substrate 33, and the circularly polarizing plate 31 (the present circular polarizing plate 110). Although the organic EL display device having the organic functional layer 36 will be 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, the thin film transistor 40 is formed on the substrate 33 in a desired shape. Then, an interlayer insulating film 34 is formed, and then the pixel electrode 35 is formed into a film by sputtering and patterned. Thereafter, the organic functional layer 36 is laminated.

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

In the case where the circular polarizing plate 110 is used as the circular polarizing plate 31, the order of lamination will be described with reference to an enlarged view of a portion C surrounded by a broken line in FIG. When the circular polarizing plate 110 is used as the circular polarizing plate 31, the phase difference layer 4 located on the circular polarizing plate 110 is disposed on the substrate 33 side. (C1) is an enlarged view in which the first embodiment of the circular polarizing plate 110 is used as the circular polarizing plate 31, and (C2) is used in the second embodiment of the circular polarizing plate 110 as circularly polarized light. An enlarged view of the board 31.

Next, members other than the present polarizing film 31 (circular polarizing plate 110) of the EL display device 30 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 (such as DLC (Diamond-like carbon)). When the pixel electrode 35 is of a reflective type, light is emitted in the opposite direction of the substrate 33. Therefore, not only a transparent material but also an opaque material 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. Moreover, these substrates are not limited to a plate shape, and may be a film.

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

A wiring electrode of the thin film transistor 40 is provided on the substrate 33. The wiring electrode has a low resistance, and has a function of electrically connecting to the pixel electrode 35 to suppress the resistance value to a low level. Usually, the wiring electrode 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 formed by sputtering or vacuum deposition to form an inorganic material such as cerium oxide or tantalum nitride such as SiO ₂ or the like; and SOG (Spin-on-Glass, A coating film of a resinous material such as a ruthenium oxide layer, a photoresist, a polyimide, or an acrylic resin which is formed by spin-coating glass is insulating.

Ribs 41 are formed on the interlayer insulating film 34. The ribs 41 are disposed on the peripheral portion of 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, 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 source, and a cathode electrode 37 will be described. The organic functional layer 36 has at least one layer of a hole transport layer and a light-emitting layer, for example, an electron injection transport layer, a light-emitting layer, a hole transport layer, and a hole injection layer.

Examples of the pixel electrode 35 include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), ZnO, and SnO _{2 .} And In ₂ O ₃ and the like; more preferably ITO or IZO. The thickness of the pixel electrode 35 may be a certain thickness or more sufficient for hole injection, and is preferably about 10 to 500 nm.

The pixel electrode 35 can be formed by a vapor deposition method (preferably, a sputtering method). The sputtering gas is not particularly limited, and an inert gas such as Ar, He, Ne, Kr or Xe or a mixed gas thereof may be used.

As a constituent material of the cathode electrode 37, for example, a metal element such as K, Li, Na, Mg, La, Ce, Ca, Sr, Ba, Al, Ag, In, Sn, Zn, or Zr may be used, in order to improve the action of the electrode. Stability, preferably using two components selected from the exemplified metal elements Or an alloy system of three components. 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%), etc.

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, preferably 1 to 500 nm.

The hole injection layer has a function of facilitating injection of holes from the pixel electrode 35, and the hole transport layer has a function of 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-charged hole transport layer, and the thickness of the electron injecting and transporting layer are not particularly limited, and depending on the formation method, it is preferably 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 film, the vacuum injection method can be used for the formation of the hole injection transport layer, the light-emitting layer, and the electron injection transport layer.

As the light-emitting source, the organic functional layer 36 can be used: those who emit light from a singlet exciton (fluorescence); those who use light from a triplet exciton (phosphorescence); and those that use light from a singlet exciton (fluorescence) Those who use the organic functional layer of the light-emitting (phosphorescent) from the triplet exciton; those formed by the organic matter; the organic functional layer including the organic-former and the inorganic-formed; the polymer material; the low-molecular material; Contains materials for polymers and materials with low molecular weight. However, the present invention is not limited thereto, and an organic functional layer 36 for use as an EL element using various known persons can be used for the present EL display device 30.

A desiccant 38 is disposed in the space between the cathode electrode 37 and the sealing cover 39. The reason for this 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 configuration of another aspect of the EL display device 30. The EL display device 30 has a sealing structure using a film sealing film 42, so that light can be obtained from the opposite surface of the array substrate.

As the film sealing film 42, a DLC film in which DLC (Diamond-Like Carbon) is vapor-deposited on a film of an electrolytic capacitor is preferable. The DLC film has a characteristic of poor moisture permeability and high moisture resistance. Further, it may be formed by directly depositing a DLC film or the like on the surface of the cathode electrode 37. Further, the resin film and the metal film may be laminated in a plurality of layers to form the film sealing film 42.

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

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

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

The 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 the light source (for example, the high pressure mercury lamp) 111 as the light source is first homogenized by the first lens array 112, the second lens array 113, the polarization conversion element 114, and the superimposing lens 115 at the beam cross section. And polarized.

Specifically, the first lens array 112 in which the light beams emitted from the light source 111 are formed in a matrix by the minute lenses 112a is divided into a plurality of minute light beams. The second lens array 113 and the superimposing lens 115 are provided so that the respective divided light beams are irradiated to the entire three liquid crystal panels 140R, 140G, and 140B to be illuminated. Therefore, the entire incident side surface 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 overlap lens 115. Thereby, the random polarized light from the light source is converted into a polarized light having a specific polarization direction in advance, thereby reducing the amount of light loss at the incident side polarizing element and exhibiting an effect of improving the brightness of the screen.

The light which is uniformized and polarized by the brightness as described above is sequentially separated into a red channel, a green channel, and a blue channel by the dichroic mirrors 121, 123, 132 for separating the three primary colors of RGB via the mirror 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 the incident side thereof. 142, polarizing elements 143 are respectively disposed on the exit side. The polarizing element 142 and the polarizing element 143 can use the present polarizing film.

The polarizing element 142 and the polarizing element 143 disposed on each of the RGB optical paths are arranged such that their 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 based on a video signal.

The polarizing film 100 is preferably used as a polarizing film excellent in durability in optical paths such as a blue channel, a green channel, and a red channel by selecting a type of dichroic dye suitable for the corresponding channel.

According to the image data of the liquid crystal panels 140R, 140G, and 140B, the incident light is transmitted at different transmittances corresponding to each pixel, and the optical image formed thereby is synthesized by intersecting the dichroic color 150, and is projected by The lens 170 is enlarged and projected onto the screen 180.

Examples of the electronic paper include: those which are displayed by molecules such as optical anisotropy and dye molecule alignment; and those which are displayed by particles such as electrophoresis, particle movement, particle rotation, and phase change; a displayer; a displayer by color development/phase change of a molecule; a displayer by absorption of light by a molecule; a self-luminous display by coupling of electrons and a hole, and the like. More specifically, examples thereof include microcapsule electrophoresis, horizontal movement electrophoresis, vertical mobile electrophoresis, spherical torsion sphere, magnetic torsion sphere, cylindrical torsion sphere method, charged toner, electronic powder fluid, magnetophoresis type, magnetic Thermal sensing, electrowetting, light scattering (transparent/white turbidity change), cholesteric liquid crystal/photoconductive layer, cholesteric liquid crystal, bistable nematic liquid crystal, ferroelectric liquid crystal, 2-color pigment-liquid crystal dispersion type, movable film The use of leuco dyes for color development, photochromism, electrochromism, electrodeposition, flexible organic EL, and the like. E-paper can be used not only for personal use of text or images, but also for advertising display (signage). The thickness of the electronic paper can be made thin by the polarizing film.

As a stereoscopic display device, for example, a method of alternately arranging different retardation films as in the case of a micro magnetic pole method has been proposed (Japanese Patent Laid-Open Publication No. 2002-185983), but if the bias is used, Since the light film is easily patterned by printing, inkjet, photolithography, or the like, the manufacturing process of the display device can be shortened, and a retardation film is not required.

[Examples]

Hereinafter, the present invention will be described in further detail by way of examples. In the examples, "%" and "parts" are % by mass and parts by mass unless otherwise specified.

In the present embodiment, the following dichroic dye (1) was used.

Production of Compound (1-1) (Compound represented by the following (1-1))

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

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

¹ H-NMR (CDCl ₃ ) of the 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 represented by the following (1-7))

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

5.00 g of the compound (1B), 4.63 g of 4-butoxyphenol, 0.23 g of DMAP and 25 g of chloroform were mixed, and the mixture was stirred at 5 ° C for 10 minutes under a light-shiel-nitrogen atmosphere. IPC 2.58 g was added dropwise to the obtained mixture over 5 minutes, and further stirred for 4 hours. 75 g of methanol was added to the obtained reaction liquid to carry out crystallization, and the crystals were collected by filtration. The crystals were dissolved in 50 g of dimethylacetamide, and the insolubles were subjected to halomite filtration. The filtrate was recovered and crystallization was carried out using water. The obtained crystal was further dissolved in 50 g of tetrahydrofuran and the insoluble matter was removed by filtration, and then heptane was added to carry out crystallization, followed by vacuum drying, whereby 4.66 g of the compound (1-7) was obtained. The yield was 60% based on the compound (1B).

¹ H-NMR (CDCl ₃ ) of the 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 the present embodiment, the following polymerizable liquid crystal compound was used.

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

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

The compound (4-8) is synthesized by referring to the synthesis method of the above 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) was heated to 140 ° C, the phase was transferred to a nematic phase at 131 ° C when the temperature was lowered, and the phase was transferred to a smectic phase A at 80 ° C, and the phase was converted to a smectic phase B at 68 ° C. .

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

The 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) was heated to 140 ° C, the phase was transferred to a nematic phase at 106 ° C when the temperature was lowered, and the phase was transferred to the smectic phase A at 103 ° C, and the phase was transferred to the smectic phase B at 86 ° C. .

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

The 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) was heated to 140 ° C, the phase was transferred to a nematic phase at 119 ° C when the temperature was lowered, and the phase was transferred to a smectic phase A at 100 ° C, and the phase was converted to a smectic phase B 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 to obtain a polarizing film-forming composition (A). In addition, the "compound (1-7)" of the so-called dichroic dye used herein, The compound represented by the above formula (1-7), and other compounds used as the dichroic dye are also numbered according to the formula. The same is true below.

1. X-ray diffraction measurement

After coating a 2% by mass aqueous solution (composition for forming an alignment layer) of polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified, manufactured by Wako Pure Chemical Industries, Ltd.) on a glass substrate by a spin coating method, and drying, A film having a thickness of 100 nm was formed. Then, an alignment layer is formed by subjecting the surface of the obtained film to a rubbing treatment. The friction treatment system uses a semi-automatic friction device (trade name: LQ-008 type, manufactured by Changyang Engineering Co., Ltd.), and uses 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 applied onto the alignment film thus prepared by a spin coating method, and dried by heating on a hot plate at 120 ° C for 1 minute, and then rapidly cooled to room temperature in the above alignment layer. A dry film is formed on the film. Then, using a UV irradiation device (SPOT CURE SP-7: manufactured by Ushio Electric Co., Ltd.), the dried film was irradiated with ultraviolet rays at an exposure amount of 2000 mJ/cm ² (365 nm basis), whereby the dried film was used. The polymerizable liquid crystal compound contained therein is polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal composition, whereby a polarizing film is formed from the dried film. The thickness of the polarizing film at this time was measured by a laser microscope (manufactured by Olympus Co., Ltd., OLS3000) and found to be 1.7 μm.

X-ray diffraction measurement was performed on the polarizing film in the same manner using an X-ray diffraction apparatus X' Pert PRO MPD (manufactured by Spectris Co., Ltd.), and the peak half-height width (FWHM, Full Width at) was obtained in the vicinity of 2θ=20.2°. Half Maximum) = a steep diffraction peak of about 0.17° (Bulegg crest). Moreover, the incident from the vertical direction of the rubbing also obtained the same result. The order period (d) obtained from the peak position is about 4.4 Å, and it is confirmed that a structure reflecting the high-order layer phase is formed.

2. Fabrication of a light alignment film on a transparent film

Using a cellulose triacetate film (KC8UX2M, manufactured by Konica Minolta Co., Ltd.) as a transparent substrate, the photo-alignment polymer represented by the following formula (3) was dissolved in toluene to 5 by a bar coating method. % of the liquid was formed and dried at 120 ° C to obtain a dry film. The dried coating film was irradiated with polarized UV to obtain a photo-alignment film. The polarized UV treatment was carried out under the conditions of an intensity of 100 mJ measured at a wavelength of 365 nm using a UV irradiation apparatus (SPOT CURE SP-7: manufactured by Ushio Electric Co., Ltd.).

3. Production of polarizing film

The polarizing film-forming composition (A) was applied onto the film having the photo-alignment film obtained in the above manner by a bar 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. Then, a layer formed of the composition for forming a polarizing film was irradiated with ultraviolet rays having an exposure amount of 2000 mJ/cm ² (365 nm basis) using a UV irradiation device (SPOT CURE SP-7: manufactured by Ushio Electric Co., Ltd.). The polymerizable liquid crystal compound contained in the dried film is polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal composition, whereby a polarizing film is formed from the dried film. The film thickness of the polarizing film at this time was measured by a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 1.6 μm. Such a winner is a polarizing element comprising a polarizing film and a transparent substrate.

4. Determination of polarizedness, transmittance, and hue

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

A device equipped with a clip with a polarizing element is provided on a spectrophotometer (manufactured by Shimadzu Corporation, UV-3150), and the transmission axis direction is measured by a two-beam method at a wavelength of 380 nm to 780 nm. Transmittance (T ¹ ) and transmittance in the direction of the absorption axis (T ² ). The clip is provided with a mesh that cuts the amount of light by 50% on the reference side. The single object penetration rate and the degree of polarization at each wavelength are calculated by the following formulas (Formula 1) and (Formula 2), and the visibility correction is performed by the 2D field of view (C light source) of JIS Z 8701 to calculate the visibility-corrected single object. Transmittance (Ty) and visibility corrected polarization (Py). Further, using the color matching function of the C light source, the chromaticities a ^* and b ^* in the L ^* a ^* b ^* (CIE) color system are calculated from the single object transmittance measured in the same manner. Further, using the color matching function of the C light source, the orthogonal a ^* and the orthogonal b ^* in the L ^* a ^* b ^* (CIE) color system are calculated from the orthogonal transmittance measured in the same manner. The closer the values of chromaticity a ^* , chromaticity b ^* , orthogonal a ^*, and orthogonal b ^* are to zero, the more it is judged to be a neutral hue. These results are shown in Table 4.

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

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

Example 2

1. Production of polarizing film

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

2. Determination of polarizedness, transmittance, and hue

By measuring the visibility of the prepared polarizing film by the same method as in Example 1, the single object transmittance (Ty), the visibility correction polarization (Py), the chromaticity a ^* , the chromaticity b ^* , the orthogonal a ^*, and Orthogonal b ^* , the results are 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 to obtain a polarizing film-forming composition (B).

1. Production of polarizing film

The polarizing film-forming composition (A) was changed to the polarizing film-forming composition (B), and the bar width and coating speed (#5 25 mm/s) of the bar coater were changed. A polarizing film was produced in the same manner as in Example 1. Using a laser microscope (Olympus shares) Manufactured by Co., Ltd., OLS3000) The film thickness of the polarizing film at this time was measured and found to be 1.7 μm.

2. Determination of polarizedness, transmittance, and hue

By measuring the visibility of the prepared polarizing film by the same method as in Example 1, the single object transmittance (Ty), the visibility correction polarization (Py), the chromaticity a ^* , the chromaticity b ^* , the orthogonal a ^*, and Orthogonal b ^* , the results are 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 bar of the bar coater and the coating speed (#7 20 mm/s) were changed. The film thickness of the polarizing film at this time was measured by a laser microscope (manufactured by Olympus Co., Ltd., OLS3000), and it was 2.0 μm.

2. Determination of polarizedness, transmittance, and hue

By measuring the visibility of the prepared polarizing film by the same method as in Example 1, the single object transmittance (Ty), the visibility correction polarization (Py), the chromaticity a ^* , the chromaticity b ^* , the orthogonal a ^*, and Orthogonal b ^* , the results are 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 bar of the bar coater and the coating speed (#5 50 mm/s) were changed. The film thickness of the polarizing film at this time was measured by a laser microscope (manufactured by Olympus Co., Ltd., OLS3000) and found to be 2.2 μm.

2. Determination of polarizedness, transmittance, and hue

By measuring the visibility of the prepared polarizing film by the same method as in Example 1, the single object transmittance (Ty), the visibility correction polarization (Py), the chromaticity a ^* , the chromaticity b ^* , the orthogonal a ^*, and Orthogonal b ^* , the results are shown in Table 4.

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

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

1. Production of polarizing film

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

2. Determination of polarizedness, transmittance, and hue

By measuring the visibility of the prepared polarizing film by the same method as in Example 1, the single object transmittance (Ty), the visibility correction polarization (Py), the chromaticity a ^* , the chromaticity b ^* , the orthogonal a ^*, and Orthogonal b ^* , the results are 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 of the bar of the bar coater and the coating speed (#5 50 mm/s) were changed. The film thickness of the polarizing film at this time was measured by a laser microscope (manufactured by Olympus Co., Ltd., OLS3000) and found to be 2.2 μm.

2. Determination of polarizedness, transmittance, and hue

By measuring the visibility of the prepared polarizing film by the same method as in Example 1, the single object transmittance (Ty), the visibility correction polarization (Py), the chromaticity a ^* , the chromaticity b ^* , the orthogonal a ^*, and Orthogonal b ^* , the results are shown in Table 4.

Comparative example 1

1. Production of iodine-PVA polarizing plate

A polyvinyl alcohol film having an average polymerization degree of about 2,400, a degree of saponification of 99.9 mol% or more and a thickness of 75 μm is uniaxially stretched to about 5 times in a dry state, and further impregnated in pure water at 60 ° C while being maintained in a stretched state. After 1 minute, it was immersed in an aqueous solution of iodine/potassium iodide/water in a mass ratio of 0.1/5/100 at 28 ° C for 60 seconds. Thereafter, it was immersed at 72 ° C for 300 seconds in an aqueous solution of potassium iodide / boric acid / water mass ratio of 810.5 / 7.5 / 100. 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 which adsorbed iodine on the polyvinyl alcohol resin film.

2. Determination of polarizedness, transmittance, and hue

By measuring the visibility of the produced polarizing element by the same method as in the first embodiment, the single object transmittance (Ty), the visibility corrected polarization (Py), the chromaticity a ^* , the chromaticity b ^* , the orthogonal a ^*, and Orthogonal b ^* , the results are shown in Table 4.

According to Table 4, the polarizing films of Examples 1 to 7 were thinner than the conventional iodine-PVA polarizing element. Further, the polarizing films of Examples 1 to 7 all exhibited neutral hue.

Example 8

1. Fabrication of a light alignment film on a retardation film

Using a retardation film (uniaxially stretched film WRF-S (modified polycarbonate resin), phase difference 137.5 nm, thickness 50 μm, manufactured by Teijin Chemical Co., Ltd.) instead of cellulose triacetate film (KC8UX2M, Konica Minolta) As a transparent substrate, a solution obtained by dissolving the light represented by the above formula (3) into a polymer in cyclopentanone to 5% as a transparent substrate was applied at 120 ° C by a bar coating method. Drying is carried out to obtain a dry film. The dried coating film was irradiated with polarized UV to obtain a photo-alignment film. The polarized UV treatment was carried out under the conditions of an intensity of 100 mJ measured at a wavelength of 365 nm using a UV irradiation apparatus (SPOT CURE SP-7: manufactured by Ushio Electric Co., Ltd.). Further, at this time, the irradiation direction of the polarized UV was performed at 45° with respect to the retardation axis of the retardation film.

2. Production of circular polarizer

The polarizing film-forming composition (C) was applied onto the photo-alignment film of the prepared retardation film with the photo-alignment film by a bar coating method (#7 20 mm/s) at 120 ° C. After heating and drying in a drying oven for 1 minute, it was cooled to room temperature. Then, using a UV irradiation apparatus (SPOT CURE SP-7: manufactured by Ushio Electric Co., Ltd.), the layer formed of the composition for forming a polarizing film was irradiated with ultraviolet rays having an exposure amount of 2000 mJ/cm ² (365 nm basis). The polymerizable liquid crystal compound contained in the dried film is polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal composition, whereby a polarizing film is formed from the dried film to prepare a circularly polarizing plate. The film thickness of the polarizing film at this time was measured by 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 obtained by bonding with an adhesive was bonded to the aluminum metal plate, and as a result, the metallic luster observed on the elemental material of the aluminum metal plate disappeared, and a uniform black display was obtained. It can be seen that the circularly polarizing plate made of the present polarizing film has good anti-reflection characteristics.

[Industrial availability]

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

Claims (15)

A polarizing film comprising: a polymer formed of a polymerizable liquid crystal compound; and at least one of absorption maximum values in a wavelength range of 380 to 550 nm when dispersed in the polymer to measure light absorption. The dichroic dye (1) and at least two kinds of dichroic dyes (2) having an absorption maximum in a wavelength range of 550 to 700 nm. The polarizing film of claim 1, wherein the dichroic dye (1) has a maximum absorption in a wavelength range of 400 to 550 nm when it is dispersed in a polymer formed of a polymerizable liquid crystal compound to measure light absorption. value. The polarizing film of claim 1 or 2, wherein at least two kinds of dichroic dyes having an absorption maximum in a range of 550 to 700 nm when dispersed in the polymer and measuring light absorption (2) comprise : In the case where the light absorption is measured by dispersing in the above polymer, the dichroic dye (2-1) having an absorption maximum in a wavelength range of 550 to 600 nm, and a wavelength in the range of 600 to 700 nm A dichroic dye (2-2) having an absorption maximum. The polarizing film according to any one of claims 1 to 3, wherein the polymerizable liquid crystal compound is a compound which exhibits a smectic liquid crystal phase. The polarizing film according to any one of claims 1 to 4, which can obtain a Böhler wave peak in an X-ray diffraction measurement. The polarizing film according to any one of claims 1 to 5, wherein the color coordinates a ^* value and b ^* value in the L ^* a ^* b ^* color system satisfy the relationship of the following formulas (1F) and (2F): 3 ≦ chromaticity a ^* ≦ 3 (1F) - 3 ≦ chromaticity b ^* ≦ 3 (2F). The polarizing film according to any one of claims 1 to 6, wherein the dichroic dye (1) and the dichroic dye (2) are azo compounds. The polarizing film according to any one of claims 1 to 7, wherein the dichroic dye (2) comprises a compound represented by the formula (2): [In the formula (2), n is 1 or 2; and Ar ¹ and Ar ³ are each independently a group represented by any one of the formulas (AR-1) to (AR-4): Ar ² is a base represented by the formula (AR2-1), the formula (AR2-2) or the formula (AR2-3): A ₁ and A ₂ are each independently a base represented by any one of formulas (A-1) to (A-9), and * represents a bond key: (mc is an integer from 0 to 10, and when there are 2 mcs in the same base, the two mcs are identical or different from each other)]. The polarizing film according to any one of claims 1 to 8, wherein the dichroic dye (1) comprises a compound represented by the formula (1): [In the formula (1), Y is a group represented by the formula (Y1) or the formula (Y2): (wherein L is an oxygen atom or -NR-, R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) and R ¹ is any ^one of the formula (R ¹ -1) to the formula (R ¹ -3). The base expressed: (wherein, ma is an integer of 0 to 10, and when there are two ma in the same base, the two ma are the same or different from each other; * represents a bonding bond) and R ² is a formula (R ² -1) The base represented by any of the formulas (R ² -6): (where mb is an integer from 0 to 10)]. A polarizing element obtained by disposing a polarizing film according to any one of claims 1 to 9 on a transparent substrate. A manufacturing method of the polarizing element of claim 10, comprising: a step of preparing a laminate comprising an alignment film on a transparent substrate; and a step of coating the composition on the alignment film of the laminate The composition contains: a polymerizable liquid crystal compound; and when it is dispersed in a polymer formed of the polymerizable liquid crystal compound to measure light absorption, it has a maximum absorption value in a wavelength range of 380 to 550 nm. Chromatic pigment (1), and wavelength 550~700 Two kinds of dichroic dyes (2) having an absorption maximum in the range of nm; and a solvent; and a step of polymerizing the above-mentioned polymerizable liquid crystal compound contained in the above composition. The manufacturing method of claim 11, wherein the transparent substrate is a plastic substrate, and the alignment film is a photo alignment film. A liquid crystal display device comprising the polarizing film according to any one of claims 1 to 9. A circularly polarizing plate comprising the polarizing film according to any one of claims 1 to 9 and a λ/4 layer, and satisfying the following requirements (A1) and (A2): (A1) an absorption axis of the above polarizing film and the above The angle formed by the slow phase axis of the λ/4 layer is approximately 45°; (A2) The positive retardation value of the above λ/4 layer measured by light having a wavelength of 550 nm is in the range of 100 to 150 nm. An organic EL display device comprising the circular polarizing plate of claim 14 and an organic EL element.