TWI641877B - Elliptical polarizer - Google Patents

Abstract

The object is to provide an elliptical polarizing plate that can suppress the color of reflected colors in the full range of visible light and can provide good display characteristics when used in a display device.

An elliptically polarizing plate comprising a polarizing plate and a retardation plate and satisfying all of the following formulae (1) to (4), 0.8 ≦ P (450) / P (650) ≦ 1.2 (1)

P (550) ≧ 0.7 (2)

Re (450) <Re (550) <Re (650) (3)

0.05 <1-P (450) <0.3 (4) [In the above formulas (1) to (4), P (λ) = tan {sin ^-1 ((I1 (λ) × sin Π (λ) × sin2 θ -I2 (λ) × sin Π (λ) × cos2 θ) / I2 (λ)) / 2}, I1 (λ) = (10 ^{-A1 ( λ )} -10 ^{-A2 ( λ )} ) / 2, I2 ( λ) = (10 ^{-A1 ( λ )} +10 ^{-A2 ( λ )} ) / 2, Π (λ) = Re (λ) / λ × 2 π, A1 (λ) refers to the polarizer at the wavelength λ Absorptance in the transmission axis direction, A2 (λ) is the absorption axis direction of the polarizing plate at the wavelength λ, Re (λ) is the frontal retardation at the wavelength λ, and θ is the absorption axis and the phase difference plate of the polarizing plate. Angle formed by the slow axis].

Description

Elliptical polarizer

The present invention relates to an elliptically polarizing plate and a display device including the aforementioned elliptically polarizing plate.

In flat display devices (FPDs) such as organic EL display devices, circular polarizers are widely used for the purpose of preventing reflection from external light. A circularly polarizing plate has a structure in which a linearly polarizing plate and a retardation plate (λ / 4 plate) are laminated. However, if a general positive-wavelength dispersive material is applied as a retardation plate, it cannot be displayed in the entire visible range. The phase difference of λ / 4 causes the problem of coloring of reflection color. In order to solve this problem, Patent Document 1 discloses a circularly polarizing plate using a reverse-wavelength dispersive liquid crystal material designed to have a short wavelength and low birefringence as a retardation plate; Patent Document 2 It is disclosed that a circularly polarizing plate using a polymer film material with inverse wavelength dispersibility as a retardation plate is disclosed.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3325560

[Patent Document 2] Japanese Patent Laid-Open No. 2014-123134

Theoretically, the retardation plate is designed to have a retardation of 1/4 in the full range of visible light wavelengths (so that it is "inverse wavelength dispersion"), thereby making it a circularly polarizing plate with no reflection color.

In other words, as a theoretical value, the retardation Re (450) of 450 nm for slightly blue light is 450 ÷ 4 = 112.5 nm, the retardation Re (550) of 550 nm for slightly green light is 550 ÷ 4 = 137.5 nm, and 650 nm for slightly red light The retardation Re (650) becomes 650 ÷ 4 = 162.5 nm, whereby a circularly polarizing plate having no reflection color can be obtained.

However, as for the retardation plates disclosed in the above-mentioned Patent Documents 1 and 2, although short-wavelength light can approach a theoretical value, long-wavelength light cannot be made into a theoretical value. This is because the inverse wavelength dispersive birefringence, which is a retardation plate, is obtained by subtracting the birefringence at each wavelength from the positive alignment birefringence structure and the negative alignment birefringence structure. However, the material The inherent wavelength dispersion cannot be a linear change. In the extreme, this is due to the basic principle of the so-called dispersion with larger short wavelengths and dispersion with smaller long wavelengths. Therefore, if the phase difference plate is designed as a green light with a theoretical value that is extremely high in human vision, preventing the reflection of red light will be insufficient, which may cause a problem that the so-called reflected color becomes red.

Here, an object of the present invention is to provide an elliptical polarizing plate that can suppress the coloring of reflected colors in the entire range of visible light and can provide good display characteristics when used in a display device.

The system of the present invention has the following suitable aspects [1] to [10].

[1]. An elliptically polarizing plate comprising a polarizing plate and a retardation plate, and satisfying all the following formulae (1) to (4), 0.8 ≦ P (450) / P (650) ≦ 1.2 (1)

P (550) ≧ 0.7 (2)

Re (450) <Re (550) <Re (650) (3)

0.05 <1-P (450) <0.3 (4) [In the aforementioned formulas (1) to (4), P (λ) = tan {sin ^-1 ((I1 (λ) × sin Π (λ) × sin2 θ -I2 (λ) × sin Π (λ) × cos2 θ) / I2 (λ)) / 2}, I1 (λ) = (10 ^{-A1 ( λ )} -10 ^{-A2 ( λ )} ) / 2, I2 ( λ) = (10 ^{-A1 ( λ )} +10 ^{-A2 ( λ )} ) / 2, Π (λ) = Re (λ) / λ × 2 π, A1 (λ) refers to the polarizer at the wavelength λ Absorptance in the transmission axis direction, A2 (λ) is the absorption axis direction of the polarizing plate at the wavelength λ, Re (λ) is the frontal retardation at the wavelength λ, and θ is the absorption axis of the polarizing plate and the retardation Angle of the slow axis].

[2]. The elliptically polarizing plate according to the above [1], wherein the front retardation of the retardation plate at a wavelength of 550 nm satisfies the following formula (5), 130 nm ≦ Re (550) ≦ 150 nm (5) [wherein Re (550) represents a frontal retardation at a wavelength of 550 nm].

[3]. The elliptical polarizing plate according to [1] or [2] above, wherein the absorption axis direction absorbance (A2) of the polarizing plate at the wavelength λ is all that satisfies the following formulas (6) to (8), 1 ≦ A2 (450) ≦ 6 (6)

1 ≦ A2 (550) ≦ 6 (7)

2 ≦ A2 (650) ≦ 6 (8).

[4]. The elliptical polarizing plate according to any one of [1] to [3], wherein the transmission axis direction absorbance (A1) of the polarizing plate at a wavelength λ satisfies the following formulas (9) to (11) All numbers, 0.001 ≦ A1 (450) ≦ 0.1 (9)

0.001 ≦ A1 (550) ≦ 0.1 (10)

0.002 ≦ A1 (650) ≦ 0.2 (11).

[5]. The elliptically polarizing plate according to any one of [1] to [4], wherein the absorption axis direction absorbance (A2) of the polarizing plate at a wavelength λ is to satisfy the following formulae (12) and (13) , A2 (650)> A2 (450) (12)

A2 (650)> A2 (550) (13).

[6]. The elliptical polarizing plate according to any one of [1] to [5], wherein the angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate is substantially 45 °.

[7]. The elliptical polarizing plate according to any one of [1] to [6], wherein the retardation plate is made of a polymer in an aligned state of a polymerizable liquid crystal compound Of layers.

[8]. The elliptical polarizing plate according to any one of the above [1] to [7], wherein the polymer contained in the polarizing plate is the polymer in a state containing an alignment of a mixture of a polymerizable liquid crystal compound and a dichroic pigment. Polymer of polymerizable liquid crystal compound.

[9]. A liquid crystal display device comprising the elliptically polarizing plate according to any one of [1] to [8].

[10]. An organic EL display device comprising the elliptical polarizing plate according to any one of [1] to [8].

According to the present invention, it is possible to provide an elliptical polarizing plate capable of suppressing the coloring of reflected colors in the entire range of visible light and providing good display characteristics when used in a display device.

[Best Mode for Implementing Invention]

Hereinafter, embodiments of the present invention will be described in detail. However, the scope of the present invention is not limited to the embodiments described herein, and various changes can be made without departing from the scope of the present invention.

The elliptical polarizing plate of the present invention includes a polarizing plate and a retardation plate. The elliptical polarizer of the present invention satisfies the following formulas (1) to (4): 0.8 ≦ P (450) / P (650) ≦ 1.2 (1)

P (550) ≧ 0.7 (2)

Re (450) <Re (550) <Re (650) (3)

0.05 <1-P (450) <0.3 (4).

Here, in the aforementioned formulas (1) to (4), P (λ) = tan {sin ^-1 ((I1 (λ) × sin Π (λ) × sin2 θ-I2 (λ) × sin Π (λ) × cos2 θ) / I2 (λ)) / 2}

I1 (λ) = (10 ^{-A1 (λ)} -10 ^{-A2 (λ)} ) / 2, I2 (λ) = (10 ^{-A1 (λ)} +10 ^{-A2 (λ)} ) / 2, Π (λ) = Re (λ) / λ × 2 π (unit: 弪 (radain)), A1 (λ) indicates the absorption axis direction of the polarizing plate at the wavelength λ, and A2 (λ) indicates the polarized light at the wavelength λ The absorbance in the direction of the absorption axis of the plate, Re (λ) represents the frontal retardation at the wavelength λ, and θ represents the angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate.

By satisfying the aforementioned formulas (1) to (4), the elliptically polarizing plate system can suppress the "red light leakage" of the conventional problem of inverse wavelength dispersion and phase difference, and can provide good display characteristics when used in display devices. Elliptical polarizer.

In the above formulae (1) and (2), P (λ) represents an elliptical polarization state at a wavelength of λ nm, P (450) represents an elliptically polarized state of light at a wavelength of 450 nm, and P (550) represents an The elliptically polarized state of light having a wavelength of 550 nm, and P (650) represents an elliptically polarized state of light having a wavelength of 650 nm. Here, A1 (λ) is the absorption axis direction of the polarizing plate at the wavelength λ, A2 (λ) is the absorption axis direction of the polarizing plate at the wavelength λ, and Π (λ) is the wavelength at the wavelength λ. The phase difference (no dimensional value) of the retardation plate is calculated by the positive retardation at the wavelength λ represented by Re (λ). The closer the value of P (λ) is to 1, it will be in a circularly polarized state close to a true circle.

The values of P (450) / P (650) represented by the formula (1) represent the circularly polarized light states at the wavelengths of 450nm and 650nm, respectively. The closer the value is to 1, the elliptic polarizing plate can be used to suppress the reflection color. When used in a display device, a good color tone display can be achieved. When the value of formula (1) is less than 0.8, the reflected color tends to appear blue-green. When the value of formula (1) exceeds 1.2, the reflected color tends to appear red. In the elliptically polarizing plate of the present invention, the value of P (450) / P (650) varies depending on the display device, but it is preferably 0.85 or more, more preferably 0.9 or more, more preferably 1.15 or less, and more It is preferably below 1.1.

When the value of P (λ) is small, the circularly polarized light conversion becomes insufficient, and the anti-reflection characteristic on the display device is reduced. In particular, if the value of P (550) at a wavelength of 550nm, which is the highest in visibility, is small, it will be difficult to sufficiently suppress light leakage due to reflection. Therefore, the elliptical polarizer of the present invention must satisfy the expression (2). Optical characteristics. When the value of P (550) is less than 0.7, the viewer will easily recognize light leakage. Therefore, in the present invention, the value of P (550) is preferably 0.75 or more, and more preferably 0.8 or more. The upper limit of the value of P (550) is not particularly limited, but is usually 1 by definition.

In addition, when used in a display device, in order to exhibit high anti-reflection characteristics, the value of P (λ) of the elliptically polarizing plate of the present invention is preferably 0.7 or more in the entire visible light range. That is, the wavelength on the short wavelength side of visible light The value of P (450) and the value of P (650) on the long wavelength side of visible light are both preferably 0.7 or more.

The elliptically polarizing plate of the present invention satisfies the aforementioned formula (3) that exhibits inverse wavelength dispersion. The so-called inverse wavelength dispersion refers to an optical characteristic in which the in-plane retardation value at a short wavelength is larger than the in-plane retardation value at a long wavelength. The elliptically polarizing plate of the present invention preferably satisfies Re (450) / Re (550) ≦ 1, and more preferably 0.82 ≦ Re (450) / Re (550) ≦ 0.93.

In addition, from the viewpoint of optical design of reverse wavelength dispersion characteristics, the elliptical polarizing plate of the present invention must satisfy the optical characteristics represented by the aforementioned formula (4). The aforementioned formula (4) means that for the elliptical polarization state of light having a wavelength of 450 nm, the value of P (450) is set to deviate from a specified range by 1 from a theoretical value that exhibits a circularly polarized state, and the prevention of blue light can be reduced. Performance of reflection. In particular, by satisfying the optical characteristics of the formula (4) and setting the value of P (450) / P (650) of the formula (1) to 0.8 to 1.2, a display with good color tone can be achieved. Although different depending on the display device, the value of 1-P (450) in the elliptically polarizing plate of the present invention is, for example, preferably 0.08 or more, more preferably 0.1 or more, more preferably 0.26 or less, and still more preferably 0.24 the following.

P (λ) can be arbitrarily adjusted by controlling the absorption selection characteristics of the polarizing plate or the wavelength dispersion and film thickness of the retardation plate. Specifically, the absorption selection characteristics of polarizing plates, such as the case of iodine PVA polarizing plates, can be controlled by the temperature or I ₂ concentration / KI concentration, drying conditions, etc. when dyeing. When the KI concentration is increased, compared with In the case of blue light, the absorption characteristics of red light can be improved. In addition, when the drying temperature is increased, the absorption characteristics of blue light can be improved compared to red light. In the case of a liquid crystal host-guest polarizing plate, the absorption selection characteristics can be controlled by controlling the amount or ratio of dichroic pigment added to the guest molecule. For example, when a plurality of pigments are mixed, more blue pigments are blended than other pigments, thereby selectively improving only the absorption characteristics of red light. For example, a liquid crystal compound exhibiting reverse wavelength dispersibility and a liquid crystal compound exhibiting positive dispersibility can be mixed at an arbitrary ratio, whereby the wavelength dispersibility of the retardation plate can be controlled. As the film thickness of the retardation plate becomes thinner, the retardation value decreases. As long as the film thickness is within a controllable range, by controlling the film thickness, the retardation value can be controlled more easily, for example, a liquid crystal compound exhibiting a positive dispersion and a reverse wavelength dispersion exhibiting a desired wavelength dispersion. The liquid crystal compound is mixed, and the value of P (λ) can be easily controlled to a desired value by adjusting the film thickness of the retardation plate.

In the present invention, the anti-reflection characteristics of the elliptically polarizing plate satisfying the foregoing formulae (1) to (4) are satisfied, for example, (i) the front retardation value of the retardation plate is set to be larger than the theoretical value; The wavelength dispersion of the differential plate deviates from the theoretical value; (iii) Set the absorptivity of the polarizing plate near the wavelength of 650 nm (red light) to other wavelengths than the wavelength of around 450 nm (blue light) or around 550 nm (green light). The absorptivity of the domain is large, so that control can be performed. Regarding (i), for example, the front retardation value is a value determined by Δn (λ) × d (Δn: difference in inflection rate, d: thickness of the retardation plate). When the composition is the same, the front retardation value can be increased by increasing the film thickness.

The retardation plate that can constitute the elliptically polarizing plate of the present invention has the advantages of thinness and easy and arbitrary control of wavelength dispersion, and exhibits optical anisotropy by coating and alignment of a polymerizable liquid crystal compound. A layer made of a polymer in an aligned state of the polymerizable liquid crystal compound (hereinafter also referred to as an "optical anisotropic layer") is preferred. Here, the polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable functional group (particularly, a photopolymerizable functional group). The photopolymerizable functional group refers to a group that can participate in a polymerization reaction by a living radical or an acid derived from a photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, a propenyloxy group, a methacryloxy group, and ethylene oxide. Alkyl (oxiranyl), oxetanyl and the like. Among them, acryloxy, methacryloxy, vinyloxy, ethylene oxide, and oxetanyl are preferred, and acryloxy is preferred. The liquid crystallinity may be a heat-oriented liquid crystal or a liquid-oriented liquid crystal, but in terms of controlling a dense film thickness, a heat-oriented liquid crystal is preferred. The phase order structure of the thermally-oriented liquid crystal may be a nematic liquid crystal or a smectic liquid crystal.

In the present invention, the polymerizable liquid crystal compound is particularly preferably a structure of the following formula (I) from the viewpoint of exhibiting the aforementioned reverse wavelength dispersibility.

In formula (I), Ar represents a divalent aromatic group, and this 2 The valence aromatic group includes at least one of a nitrogen atom, an oxygen atom, and a sulfur atom.

G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a carbon number. 1 to 4 alkoxy, cyano or nitro groups are substituted, and carbon atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom.

L ¹ , L ² , B ¹ and B ² each independently represent a single bond or a divalent linking group.

k and l respectively represent integers from 0 to 3, and satisfy the relationship of 1 ≦ k + l. Here, when 2 ≦ k + 1, B ¹ and B ² , G ¹ and G ² may be the same or different from each other, respectively.

E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms. Here, the hydrogen atom contained in the alkanediyl group may be replaced by a halogen atom. The -CH ₂ -contained in the alkanediyl group is Can be replaced by -O-, -Si-.

P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

G ¹ and G ² are each independently preferably a 1,4-phenyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, and may be selected from the group consisting of 1,4-cyclohexyl substituted with at least one substituent of a group consisting of a halogen atom and an alkyl group having 1 to 4 carbons; more preferably 1,4-phenyl substituted with methyl, unsubstituted 1,4-phenyl, or unsubstituted 1,4-trans-cyclohexyl; particularly preferred is unsubstituted 1,4-phenyl, or unsubstituted 1,4-trans-cyclohexyl.

Preferably, at least one of the plural G ¹ and G ² present is a divalent alicyclic hydrocarbon group; and still more preferably, G ¹ and G ² bonded to L ¹ or L ² At least one of them is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, -O-, -CH ₂ CH _2- , -CH ₂ O-, -COO-, -OCO-, -N = N-, -CR ^a = CR ^b- , or -C≡C-. Here, R ^a and R ^b represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently and preferably a single bond, -O-, -CH ₂ CH _2- , -COO-, or -OCO-.

B ¹ and B ² are each independently preferably a single bond, -O-, -S-, -CH ₂ O-, -COO-, or -OCO-, and preferably a single bond, -O-, -COO -, Or -OCO-.

From the viewpoint of exhibiting inverse wavelength dispersion, k and l are preferably in a range of 2 ≦ k + l ≦ 6, more preferably k + l = 4, and more preferably k = 2 and l = 2. If k = 2 and l = 2, it is suitable because it has a symmetrical structure.

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

Examples of the polymerizable group represented by P ¹ or P ² include epoxy groups, vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, allyloxy groups, Methacryloxy, oxiranyl, and oxetanyl.

Among them, acryloxy, methacryloxy, vinyloxy, ethylene oxide, and oxetanyl are preferred, and acryloxy is preferred.

Ar preferably has an aromatic heterocyclic ring. Examples of the aromatic heterocyclic ring include a furan ring, a benzofuran ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, And morpholine ring. Among these, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is more preferable to have a benzothiazolyl group. When Ar contains a nitrogen atom, the nitrogen atom preferably has a π electron.

In formula (I), the total number of π electrons N _π contained in the divalent aromatic group represented by Ar is preferably 10 or more, more preferably 14 or more, and even more preferably 18 or more. It is preferably 30 or less, more preferably 26 or less, and even more preferably 24 or less.

Examples of the aromatic group represented by Ar include the following groups.

In the formulae (Ar-1) to (Ar-20), the symbol * indicates a connecting portion, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyanide. Alkyl, nitro, alkylsulfinyl 1 to 12 carbons, alkylsulfinyl 1 to 12 carbons, carboxyl, fluoroalkyl 1 to 12 carbons, alkoxy 1 to 6 carbons Group, alkylthio group having 1 to 12 carbon atoms, N-alkylamino group having 1 to 12 carbon atoms, N, N-dialkylamino group having 2 to 12 carbon atoms, and N-alkane having 1 to 12 carbon atoms Aminosulfonyl or N, N-dialkylaminesulfonyl having 2 to 12 carbon atoms.

Q ^1, Q ² and Q ³ each independently represent lines ^{-CR 2 'R 3' -,} - S -, - NH -, - NR 2 '-, - CO- or -O-, R ^2' and R ^{3 '} Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Y ¹ , Y ² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group, or a halogen atom, and m is an integer of 0 to 6.

Examples of the aromatic hydrocarbon group in Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, anthracenyl, phenanthryl, and biphenyl, and phenyl is preferred. , Naphthyl, and preferably phenyl. Examples of the aromatic heterocyclic group include a carbon number of at least one hetero atom including a nitrogen atom, an oxygen atom, and a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group, and a benzothiazolyl group. The aromatic heterocyclic group of 4 to 20 is preferably a furyl group, a thienyl group, a pyridyl group, a thiazolyl group, or a benzothiazolyl group.

Y ¹ , Y ² and Y ³ may be each independently a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted. The polycyclic aromatic hydrocarbon group refers to a group derived from a condensed polycyclic aromatic hydrocarbon group or a collection of aromatic rings. A polycyclic aromatic heterocyclic group refers to a group derived from a condensed polycyclic aromatic heterocyclic group or a collection of aromatic rings.

Z ⁰ , Z ¹ and Z ² are each independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, or an alkoxy group having 1 to 12 carbon atoms. Z ^{0 is more} preferably A hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group, and Z ¹ and Z ^{2 are more} preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, and a cyano group.

Q ¹ , Q ² and Q ^{3 are} preferably -NH-, -S-, -NR ^{2 '} -, -O-, and R ^{2' is} preferably a hydrogen atom. Among them, particularly preferred are -S-, -O-, and -NH-.

Among the formulae (Ar-1) to (Ar-20), from the viewpoint of molecular stability, the formulae (Ar-6) and (Ar-7) are preferred.

In the formulae (Ar-14) to (Ar-20), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom and Z ⁰ to which it is bonded. Examples thereof include a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pyrrolidine ring. The aromatic heterocyclic group may have a substituent. In addition, Y ¹ together with the nitrogen atom and Z ⁰ to which it is bonded may be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted as described above.

By aligning such a polymerizable liquid crystal compound and forming a polymer in an aligned state of the polymerizable liquid crystal compound, a retardation plate having reverse wavelength dispersibility can be produced. In this case, the polymerizable liquid crystal compounds may be used alone or as a mixture of two or more polymerizable liquid crystal compounds having different molecular structures. In the present invention, in order to mix a polarizing plate constituting an elliptically polarizing plate or a display device incorporating the elliptically polarizing plate, and to easily control the wavelength dispersion, it is preferable to mix two or more types of polymerizable liquid crystal compounds having different wavelength dispersions. . In this case, as the polymerizable liquid crystal compound to be mixed, it is preferable to include the polymerizable liquid crystal compound represented by the formula (I).

In one aspect of the present invention, the retardation plate constituting the elliptical polarizing plate of the present invention preferably contains a polymer liquid crystal compound that is different from the polymerizable liquid crystal compound in addition to the polymerizable liquid crystal compound represented by the aforementioned formula (I). Wavelength-dispersible other polymerizable liquid crystal compounds. As another polymerizable liquid crystal compound different from the polymerizable liquid crystal compound represented by the formula (I), the polymerizable liquid crystal compound represented by the formula (I) may have a reverse wavelength with a molecular structure different from the polymerizable liquid crystal compound. Dispersive polymerization The liquid crystal compound may be a polymerizable liquid crystal compound that exhibits positive wavelength dispersibility. In a suitable embodiment of the present invention, the retardation plate constituting the elliptically polarizing plate of the present invention may include, in addition to the polymerizable liquid crystal compound represented by the above formula (I), a polymerizability exhibiting positive wavelength dispersion. Liquid crystal compound. This makes it easier to control the wavelength dispersion of the retardation plate.

In the present invention, if the liquid crystal compound constituting the retardation plate includes a polymerizable liquid crystal compound that exhibits positive wavelength dispersibility, the structure is not particularly limited, and a positive wavelength dispersibility that is generally used in this field can be used. Polymerizable liquid crystal compound. Such a polymerizable liquid crystal compound is preferably a structure represented by the following formula (II), for example.

In formula (II), G ¹ , G ² , L ¹ , L ² _, B ¹ , B ² , k, 1, E ¹ , E ² , P ¹ , and P ² are the same as the aforementioned structural formula (I) By definition, G ³ is independent of G ¹ and G ² .

In formula (II), k and l are preferably in a range of 1 ≦ k + l ≦ 6, more preferably in a range of 1 ≦ k + l ≦ 4, and more preferably a structure of k + l = 2.

Specific examples of the polymerizable liquid crystal compound exhibiting positive wavelength dispersion include the "3.8.6 Network" of liquid crystal brochures (edited by the Liquid Crystal Brochure Compilation Committee and issued by Maruzen Co., Ltd. on October 30, 2012). (Completely crosslinked type) "," 6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material "Compounds having a polymerizable group among the compounds described. As such a polymerizable liquid crystal compound, a commercially available product can also be used.

As described above, in the present invention, by setting the retardation value of the retardation plate to be larger than the theoretical value and deviating the wavelength dispersion of the retardation plate from the theoretical value, the elliptic polarizing plate can be provided to satisfy the aforementioned formula (1) ~ (4) Optical characteristics. Here, in the present invention, the so-called "deviation of the wavelength dispersion of the retardation plate from the theoretical value" means R (λ 1) / R (λ 2) ≒ λ 1 / λ 2 (λ 1 <λ 2 ). The wavelength dispersibility of the retardation plate can be adjusted by the mixing ratio of the polymerizable liquid crystal compound having reverse wavelength dispersibility and the polymerizable liquid crystal compound having positive wavelength dispersibility. The higher the ratio is, R (λ 1) / R (λ 2)> λ 1 / λ 2 (λ 1 <λ 2). Here, R (λ 1) represents a positive phase difference value at a wavelength λ 1, and R (λ 2) represents a positive phase difference value at a wavelength λ 2. Further, as the ratio of the polymerizable liquid crystal compound having positive wavelength dispersibility is higher, the retardation value of the retardation plate becomes larger. Therefore, in the present invention, for example, when two or more polymerizable liquid crystal compounds including the polymerizable liquid crystal compound represented by the formula (I) are mixed to form a retardation plate, the mixing ratio may be based on the formula (I). The molecular structure of the polymerizable liquid crystal compound or the type of the combined polymerizable liquid crystal compound may be appropriately determined, but the polymerizable liquid crystal represented by formula (I) is relative to the total amount of the fully polymerizable liquid crystal compound constituting the retardation plate. The proportion of the compound is preferably 50% by mass or more, and more preferably 60% by mass or more.

In a particularly suitable embodiment of the elliptically polarizing plate of the present invention, the retardation plate constituting the elliptically polarizing plate preferably contains a polymerization represented by the aforementioned formula (I) at a mixing ratio of 100: 0 to 50:50 The liquid crystal compound and the polymerizable liquid crystal compound represented by the formula (II) are preferably 100: 0 to 75:25.

Furthermore, in one aspect of the present invention, the front retardation of the retardation plate at a wavelength of 550 nm preferably satisfies the following formula (5): 130 nm ≦ Re (550) ≦ 150 nm (5).

When the front retardation of the retardation plate at a wavelength of 550 nm satisfies the aforementioned formula (5), it can function as a so-called 1/4 wavelength plate. In particular, it is preferable to combine a polarizing plate having a good absorption selection characteristic with a retardation plate that satisfies the aforementioned formula (5). By using this combination, a circularly polarizing plate having good anti-reflection characteristics can be obtained. When the polarizing plate and the retardation plate are combined, it is preferable that the respective optical axes are substantially 45 °.

When producing a polymer in the aligned state of a polymerizable liquid crystal compound, the polymerizable liquid crystal compound is optionally diluted with a solvent, and a composition (hereinafter, also referred to as a "composition for forming an optically anisotropic layer") is applied. The polymer is placed on a substrate or an alignment film formed on the substrate, and the solvent is optionally dried and polymerized to obtain a polymer in an aligned state of the polymerizable liquid crystal compound.

By polymerizing a polymerizable liquid crystal compound while maintaining an aligned state, a liquid crystal cured film can be obtained that maintains an aligned state. The liquid crystal cured film constitutes a retardation plate.

Polymerizable liquid crystal in composition for forming optically anisotropic layer The content of the compound (the total amount if plural types are included) is, from the viewpoint of improving the orientation of the polymerizable liquid crystal compound, 100 parts by mass of the solid content of the composition for forming an optically anisotropic layer, It is usually 70 to 99.9 parts by mass, preferably 80 to 99 parts by mass, still more preferably 85 to 97 parts by mass, and even more preferably 85 to 95 parts by mass. Here, the solid content means the total amount of components after the solvent is removed from the composition for forming an optically anisotropic layer.

In addition to the polymerizable liquid crystal compound, the composition for forming an optically anisotropic layer may include a known component such as a solvent, a polymerization initiator, a polymerization inhibitor, a photosensitizer, and a leveling agent.

As the solvent, an organic solvent that can dissolve the constituents of the composition for forming an optically anisotropic layer such as a polymerizable liquid crystal compound is preferable, and an optically anisotropic layer that can dissolve the polymerizable liquid crystal compound or the like is more preferable. A solvent that uses the constituents of the composition and is inert to the polymerization reaction of the polymerizable liquid crystal compound. Specific examples include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, and phenol; ethyl acetate, butyl acetate Ester solvents such as esters, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, ethyl lactate; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, Ketone solvents such as methylpentyl ketone and methyl isobutyl ketone; non-chlorinated aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; non-chlorinated aromatic hydrocarbon solvents such as toluene and xylene; acetonitrile And other nitrile solvents; ether solvents such as tetrahydrofuran and dimethoxyethane; and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. A combination of two or more organic solvents may be used. Of these, alcohol-soluble Agents, ester solvents, ketone solvents, non-chlorinated aliphatic hydrocarbon solvents and non-chlorinated aromatic hydrocarbon solvents.

The content of the solvent is preferably 100 to 10,000 parts by mass, more preferably 100 to 5,000 parts by mass, and more preferably 100 to 2,000 parts by mass relative to the solid content of the composition for forming an optically anisotropic layer. The solid content concentration in the composition for forming an anisotropic layer is preferably 2 to 50% by mass, more preferably 5 to 50% by mass, and even more preferably 5 to 30%.

The polymerization initiator is a compound capable of starting a polymerization reaction such as a polymerizable liquid crystal. As the polymerization initiator, a photopolymerization initiator that generates radicals upon irradiation with light is preferred. Examples of the photopolymerization initiator include a benzoin compound, a benzophenone compound, a benzyl ketal compound, an α-hydroxy ketone compound, an α-amino ketone compound, an α-acetophenone compound, and a triazine compound. , Iodonium salts and phosphonium salts. Specific examples include Irgacure (Irgacure) (registered trademark) 907, Irgacure184, Irgacure651, Irgacure819, Irgacure250, Irgacure369 (all of which are made by Ciba Japan (stock)), SEIKUOL (registered trademark) BZ, SEIKUOL Z, SEIKUOL BEE (registered trademark) All of the above are made by Seiko Chemical (stock), kayacure (kayacure) (registered trademark) BP100 (made by Nippon Kayakusho (stock)), kayacure UVI-6992 (made by Dow), Adeka optomer (registered trademark) SP-152, Adeka optomer SP-170 (all of the above are made by ADEKA), TAZ-A, TAZ-PP (the above are made by Japanese siberhegner) and TAZ-104 (made by Sanwa Chemical). Among these, an α-acetophenone compound is preferred, and as the α-acetophenone compound, 2-methyl-2-morpholinyl-1- (4-methylsulfonylphenyl) ) Propane-1-one, 2-dimethylamino-1- (4-morpholinylphenyl) -2-benzylbutane-1-one, and 2-dimethylamino-1- (4 -Morpholinylphenyl) -2- (4-methylphenylmethyl) butane-1-one and the like, and more preferably, for example, 2-methyl-2-morpholinyl-1- (4- Methanesulfonylphenyl) propane-1-one and 2-dimethylamino-1- (4-morpholinylphenyl) -2-benzylbutane-1-one. Examples of commercially available products of the α-acetophenone compound include Irgacure 369, 379EG, and 907 (above manufactured by BASF Japan) and SEIKUOL BEE (manufactured by Seiko Chemical Co., Ltd.).

Since the photopolymerization initiator can fully utilize the energy generated from the light source and is excellent in productivity, the maximum absorption wavelength is preferably 300 nm to 380 nm, and more preferably 300 nm to 360 nm.

The content of the polymerization initiator is generally 0.1 to 30 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound. It is 0.5 to 10 parts by mass.

The polymerization reaction of a polymerizable liquid crystal compound can be controlled by blending a polymerization inhibitor. Examples of the polymerization inhibitor include hydroquinones having a substituent such as hydroquinone and an alkyl ether; catechols having a substituent such as an alkyl ether such as butyl catechol; and catechols , 2,2,6,6-tetramethyl-1-piperidinyloxy radicals and other free radical trapping agents; thiophenols; β-naphthylamines and β-naphthols.

The content of the polymerization inhibitor is usually 0.1 to 30 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound. The amount is preferably 0.5 to 10 parts by mass.

Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracenes having a substituent such as anthracene and alkyl ether; phenothiazine; and rubrene.

By using a photosensitizer, the sensitivity of a photopolymerization initiator can be made high. The content of the photosensitizer is usually 0.1 to 30 parts by mass, and preferably 0.5 to 10 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound.

Examples of the leveling agent include organic-modified silicone oil-based, polyacrylate-based, and perfluoroalkyl-based leveling agents. Specific examples include DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all of which are made by Toray‧Dowcorning (stock)), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001 (the above are all made by Shin-Etsu Chemical Industry Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all above are made by Momentive Performance Materials Japan contract company ), Fluorinert (fluorinert) (registered trademark) FC-72, the same FC-40, the same FC-43, the same FC-3283 (the above are all Sumitomo 3M (stock) system), MEGAFACE (registered trademark) R-08, the same R-30, same as R-90, same as F-410, same as F-411, same as F-443, same as F-445, same as F-470, same as F-477, same as F-479, same as F-482, same as F-483 (both are DIC (stock) system), F-Top (brand name) EF301, same EF303, same EF351, and EF352 (all of the above are Mitsubishi Material Electronic Chemicals (stock) system), Surflon (registered trademark) S- 381, same as S-382, same as S-383, same as S-393, same as SC-101, same as SC-105, KH-40, SA-100 (all above are made by AGC seimi chemical (stock) system), trade name E1830 Same as E5844 (made by Daikin Fine Chemical Research Institute), BM-1000, BM-1100, BYK-352, BYK-353, and BYK-361N (all are trade names: BM Chemie). It is also possible to combine two or more leveling agents.

By using a leveling agent, a smoother optically anisotropic layer can be formed. In addition, in the manufacturing process of the retardation plate, the fluidity of the composition for forming an anisotropic layer can be controlled, or the cross-linking density of the retardation plate can be adjusted. The content of the leveling agent is usually 0.1 to 30 parts by mass, and preferably 0.1 to 10 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound.

<Coating of the composition for forming an anisotropic layer>

When manufacturing a polymer in an aligned state of a polymerizable liquid crystal compound, the composition for forming an optically anisotropic layer is applied to a substrate or an alignment film formed on the substrate, but the substrate is preferably Resin substrate. The resin substrate is usually a transparent resin substrate. The so-called transparent resin substrate refers to a substrate having a light-transmitting property through which light (especially visible light) can be transmitted. The so-called light-transmitting property refers to a transmittance of 80% for a light beam with a wavelength of 380 to 780 nm. The above characteristics. The resin substrate is usually used in a film form, and preferably used in a long film roll.

Examples of the resin constituting the substrate include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; Cellulose ester Polyethylene naphthalate; polycarbonate; polyfluorene; polyetherfluorene; polyetherketone; polyphenylene sulfide; and polyphenylene oxide. Among them, a substrate made of a polyolefin such as polyethylene, polypropylene, norbornene-based polymer is preferred.

The thickness of the substrate is usually 5 to 300 μm, and preferably 20 to 200 μm. Further, by peeling off the substrate and transferring only the polymer in the aligned state of the polymerizable liquid crystal compound, a further thin film effect can be obtained.

An alignment film may be formed on the surface coated with the composition for forming an optically anisotropic layer on a substrate. The so-called alignment film has an alignment control force that aligns the polymerizable liquid crystal compound in a desired direction.

The alignment film is preferably one having a solvent resistance which does not dissolve due to application of a composition for forming an optically anisotropic layer, and a heat treatment system for removing a solvent or an alignment of a polymerizable liquid crystal compound described later. With heat resistance. Examples of the alignment film include an alignment film including an alignment polymer, a photo-alignment film, and a groove alignment film having an uneven pattern or a plurality of grooves on the surface.

Such an alignment film can facilitate the alignment of the polymerizable liquid crystal compound. In addition, depending on the type of the alignment film or the friction conditions, various alignments such as horizontal alignment, vertical alignment, hybrid alignment, and oblique alignment can be controlled. The horizontal retardation of the rod-like liquid crystal compound or the vertical alignment of the disc-shaped liquid crystal compound can control the value of the front retardation.

The thickness of the alignment film is usually in the range of 10 to 10,000 nm, preferably in the range of 10 to 1000 nm, and more preferably in the range of 50 to 200 nm.

When the alignment polymer is contained, examples of the alignment polymer include polyamines or gelatins having a fluorene bond, polyfluorine and polyethylene of a polyimide having a fluorimine bond and a hydrolyzate thereof, and polyethylene. Alcohol, alkyl modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylates. Among these, polyvinyl alcohol is preferred. Two or more types of alignment polymers may be combined.

An alignment film containing an alignment polymer is generally obtained by dissolving an alignment polymer in a solvent, applying the obtained alignment polymer composition to a substrate, and removing the solvent to form a coating film. Or it can be obtained by apply | coating an alignment polymer composition to a base material, removing a solvent, and forming a coating film, and rubbing this coating film.

The concentration of the alignment polymer in the alignment polymer composition may be in a range in which the alignment polymer can be completely dissolved in a solvent. The content of the alignment polymer relative to the alignment polymer composition is preferably 0.1 to 20% by mass, and more preferably 0.1 to 10% by mass.

Aligned polymer compositions are commercially available. Examples of commercially available alignment polymer compositions include SUNEVER (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), OPTMER (registered trademark, manufactured by JSR (stock)), and the like.

Examples of the method for applying the alignment polymer composition to the substrate include the same method as the method for applying the composition for forming an optically anisotropic layer to the substrate described later. Examples of a method for removing the solvent contained in the alignment polymer composition include a natural drying method, a ventilating drying method, a heating drying method, and a reduced-pressure drying method.

A rubbing treatment may be applied to the coating film formed of the alignment polymer composition. By applying the rubbing treatment, an alignment control force can be imparted to the coating film.

As a method of the rubbing treatment, for example, a method of winding the rubbing cloth and rotating the rubbing roller, and contacting the coating film with the rubbing roller is mentioned. When performing the rubbing treatment, as long as the masking is performed, a plurality of regions (patterns) with different alignment directions may be formed on the alignment film.

The photo-alignment film is generally obtained by applying a composition for forming a photo-alignment film to a substrate, and removing polarized light (preferably polarized UV) after removing the solvent. A polymer or monomer having a photoreactive group, and a solvent. The light alignment film can arbitrarily control the direction of the alignment control force by selecting the polarization direction of the polarized light.

The so-called photoreactive group refers to a group that generates alignment energy by light irradiation. Specifically, examples of the photoreaction bases that become the origin of the alignment energy include participation in alignment induced reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, or photodecomposition reactions of molecules generated by light irradiation. . The photoreactive group is preferably an unsaturated bond, particularly a group having a double bond, and has a group selected from a carbon-carbon double bond (C = C bond), a carbon-nitrogen double bond (C = N bond), A group of at least one of the group formed by the nitrogen-nitrogen double bond (N = N bond) and the carbon-oxygen double bond (C = O bond) is particularly preferred.

Examples of the photoreactive group having a C = C bond include a vinyl group, a polyalkenyl group, a fluorenyl group, an oxazolyl group, an oxazolyl group, a chalcone group, and a cinnamyl group. Examples of the photoreactive group having a C = N bond include Structural bases such as aromatic Schiff base and aromatic fluorene. Examples of the photoreactive group having an N = N bond include azophenyl, azonaphthyl, aromatic heterocyclic azo, diazo, formazan, and azo oxide. Base of phenyl structure. Examples of the photoreactive group having a C = O bond include a diphenyl ketone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have substituents such as alkyl, alkoxy, aryl, allyloxy, cyano, alkoxycarbonyl, hydroxyl, sulfonic acid, and halogenated alkyl.

The groups participating in the photodimerization reaction or the photocrosslinking reaction are preferred because they have excellent alignment. Among them, a photoreactive group participating in a photodimerization reaction is also preferable, and from the viewpoints that the amount of polarized light required for alignment is small, and a thermal alignment film or an excellent photoalignment film with excellent stability over time can be easily obtained , Preferably cinnamyl and chalcone. As the polymer having a photoreactive group, it is particularly preferable that the end portion of the side chain of the polymer has a cinnamyl group having a cinnamic acid structure.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be adjusted to at least 0.2 according to the type of polymer or monomer or the thickness of the photo-alignment film used for the purpose. A mass% or more is preferable, and a range of 0.3 to 10 mass% is more preferable. The composition for forming a photo-alignment film may include a polymer material such as polyvinyl alcohol or polyimide or a photosensitizer within a range that does not significantly impair the characteristics of the photo-alignment film.

As a method for applying the composition for forming a photo-alignment film to a substrate, the same method as the method for applying the composition for forming an optically anisotropic layer to a substrate described later can be exemplified. Formed as a self-coated photo-alignment film The method for removing the solvent from the composition is, for example, the same method as the method for removing the solvent from the alignment polymer composition.

When the polarized light is irradiated, the product obtained by removing the solvent from the composition for forming a photo-alignment film coated on a substrate may be directly irradiated with polarized light, or may be irradiated with polarized light from the substrate side and transmitted through the substrate. Form of exposure. The polarized light is preferably substantially parallel light. The wavelength of the polarized light to be irradiated may be a wavelength region where the photoreactive group of the polymer or monomer having the photoreactive group can absorb light energy. Specifically, UV (ultraviolet) having a wavelength in a range of 250 nm to 400 nm is particularly preferred. Examples of the light source for irradiating polarized light include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, KrF, and ArF ultraviolet lasers. Among them, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferred because of their high luminous intensity of ultraviolet light with a wavelength of 313 nm. The light from the aforementioned light source is irradiated with an appropriate polarizing layer to irradiate with polarized UV light. Examples of the polarizing layer include polarizing filters, polarizing chirps such as Glan-Thompson, Glan-Taylor, and wire-grid-type polarizing light. Floor.

<Coating of the composition for forming an anisotropic layer>

The composition for forming an optically anisotropic layer is applied onto the substrate or the alignment film. Examples of a method for applying the composition for forming an anisotropic layer on a substrate include an extrusion coating method, a direct gravure coating method, and a reverse gravure coating method. gravure coating), CAP coating method, slit coating method, die coating method, and the like. In addition, a method of performing coating using a coating machine such as a dip coater, a bar coater, or a spin coater can also be mentioned. Among these, from the viewpoint of continuous coating in the form of Roll to Roll, CAP coating method, spray coating method, dip coating method, gap coating method, die coating method, and bar coating are preferred. Machine coating method. When applying in a Roll to Roll format, a composition for forming a photo-alignment film may be applied to a substrate to form an alignment film, and then a composition for forming an optically anisotropic layer may be continuously applied to the substrate. On the resulting alignment film.

<Drying of Composition for Forming Optical Anisotropic Layer>

Examples of the drying method for removing the solvent included in the composition for forming an optically anisotropic layer include methods such as natural drying, ventilation drying, heating drying, drying under reduced pressure, and combinations thereof. Among them, natural drying or heat drying is preferred. The drying temperature is preferably in the range of 0 to 250 ° C, more preferably in the range of 50 to 220 ° C, and more preferably in the range of 60 to 170 ° C. The drying time is preferably 10 seconds to 20 minutes, and more preferably 30 seconds to 10 minutes. The composition for forming a photo-alignment film and the alignment polymer composition can be similarly dried.

<Polymerization of Polymerizable Liquid Crystal Compound>

In the present invention, as a method for polymerizing the polymerizable liquid crystal compound, photopolymerization is preferable. The optically anisotropic layer-forming composition containing a polymerizable liquid crystal compound is coated on a substrate or an alignment film to form a laminate, and the laminate is irradiated with active energy rays to perform photopolymerization. As irradiated The performance line depends on the type of the polymerizable liquid crystal compound (especially the type of the photopolymerizable functional group of the polymerizable liquid crystal compound) contained in the dry film. If a photopolymerization initiator is included, it depends on the light. The type of the polymerization initiator and the amount thereof are appropriately selected. Specifically, one or more kinds of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α rays, β rays, and γ rays can be mentioned. Among them, from the viewpoint of easily controlling the progress of the polymerization reaction and the viewpoint that the photopolymerization device can use a wide range of users in the field, ultraviolet light is preferred, and the polymerization is selected in such a manner that photopolymerization can be performed by ultraviolet light. The kind of the liquid crystal compound is preferable.

When the composition for forming an optically anisotropic layer contains a photopolymerization initiator, it is preferable to select a type of the photopolymerization initiator in such a manner that photopolymerization can be performed by ultraviolet rays.

As the light source of the aforementioned active energy ray, for example, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, xenon lamp, halogen lamp, carbon arc lamp, tungsten lamp, gallium lamp, excimer laser, emission wavelength range 380 ~ 440nm LED light source, chemical lamp, black light, microwave excited mercury lamp, metal halide lamp, etc.

The time of irradiating light is usually 0.1 second to 10 minutes, preferably 0.1 second to 1 minute, still more preferably 0.1 second to 30 seconds, and more preferably 0.1 second to 10 seconds.

If it is the said range, an optically anisotropic layer which is more excellent in transparency can be obtained.

In the present invention, it can be controlled by adjusting the film thickness of the retardation plate. Control the retardation value of the phase difference plate. As long as the composition constituting the retardation plate is the same, the retardation value can be increased by increasing the film thickness. In addition, if the elliptically polarizing plate is composed of a combination of a polarizing plate of the same composition and a retardation plate of the same composition, by increasing the film thickness of the retardation plate, the above formula (1) of the elliptically polarizing plate can be made. The value of P (450) / P (650) becomes smaller. The thickness of the retardation plate (optical anisotropic layer) of the present invention can be appropriately determined in accordance with the type of the polymerizable liquid crystal compound constituting the retardation plate and the like so as to obtain a desired retardation value. It is preferably 0.1 to 5 μm, more preferably 0.5 to 4 μm, and even more preferably 1 to 3 μm. For example, the film thickness can be controlled by adjusting the amount of the solvent contained in the composition for forming an optically anisotropic layer or the thickness of a coating film made of the composition for forming an optically anisotropic layer. For example, the thickness of the coating film can be adjusted by changing the thickness of the wire of the wire rod during coating, adjusting the discharge amount of the die coater, or changing the groove depth or peripheral speed of the micro gravure coater.

The elliptical polarizing plate of the present invention includes at least one polarizing plate. The so-called polarizing plate refers to a material having a function of extracting linearly polarized light from natural light that strikes a person. Specific examples of the polarizing plate include a PVA polarizer formed by adsorbing and aligning a dichroic dye with iodine or a dichroic dye in a polyvinyl alcohol-based resin film (PVA) after uniaxial stretching, and a polymer film ( (Protective film) a polarizing plate formed by protecting one or both sides of the PVA polarizer. In this case, as the protective film, for example, a transparent resin film can be used. Examples of the transparent resin include cellulose acetate resins represented by cellulose triacetate or cellulose diacetate, and polymethyl methacrylate as Typical methacrylic resins, polyester resins, polyolefins Resin, polycarbonate resin, polyetheretherketone resin, polyfluorene resin, and the like. Alternatively, a liquid crystal host-guest polarizer may be used. As the liquid crystal host-guest polarizing plate, for example, JP 2012-58381, JP 2013-37115, International Publication No. 2012/147633, and International Publication No. 2014/091921 can be used. The thickness of the polarizer is not particularly limited, but a thickness of usually 0.5 to 35 μm can be used.

The polarizing plate is a thin film which is provided with polarization selectivity by orienting iodine or a dichroic dye in an extended PVA or an aligned liquid crystal. The major axis direction of the iodine-PVA complex or dichroic pigment is called the absorption axis, and the minor axis direction of the iodine-PVA complex or dichroic pigment is called the transmission axis. Completely linearly polarized light parallel to the absorption axis / transmission axis is produced by osmium or the like and passed through, and the respective absorbances can be measured from the light intensity before and after the pass. As described above, in the present invention, by controlling the absorption characteristics of the polarizing plate, the optical characteristics of the elliptical polarizing plate can also be controlled. For example, in the case of an elliptical polarizing plate composed of a retardation plate having the same composition, the polarizing plate used has an absorptivity compared to a wavelength near 450 nm (blue light) or a wavelength near 550 nm (green light). In other words, a polarizing plate (polarizing plate with a bluish hue) having a greater absorption to a wavelength of around 650 nm (red light), thereby making P (450 in the aforementioned formula (1) of the elliptical polarizing plate) ) / P (650) becomes smaller. In particular, in order to satisfy the optical characteristics of the foregoing formulae (1), (2), and (4), the elliptical polarizing plate of the present invention can control the absorbance of the polarizing plate.

Specifically, it is preferable that the absorbance (A2) in the absorption axis direction of the polarizing plate satisfies all of the following formulae (6) to (8).

1 ≦ A2 (450) ≦ 6 (6)

1 ≦ A2 (550) ≦ 6 (7)

2 ≦ A2 (650) ≦ 6 (8).

The polarizing plate has good optical absorption characteristics in the entire range of visible light by having optical characteristics satisfying the aforementioned formulae (6) to (8).

The absorbance (A1) in the transmission axis direction of the polarizing plate preferably satisfies all of the following formulas (8) to (10).

0.001 ≦ A1 (450) ≦ 0.1 (9)

0.001 ≦ A1 (550) ≦ 0.1 (10)

0.002 ≦ A1 (650) ≦ 0.2 (11).

The polarizing plate has optical characteristics satisfying the aforementioned formulae (9) to (10), and can obtain good light transmission characteristics in the entire range of visible light.

Furthermore, in order to increase the absorption of red light near a wavelength of 650 nm, the absorbance (A2) in the direction of the absorption axis of the polarizing plate preferably satisfies the following formulas (12) and (13).

A2 (650)> A2 (450) (12)

A2 (650)> A2 (550) (13).

The polarizing plate can effectively suppress the reflection of red light by having the optical characteristics satisfying the foregoing formulae (12) and (13), and can suppress the coloration of the reflected color in the full range of wavelengths of visible light including red light, and is used for display The device is an elliptically polarizing plate that can provide good display characteristics.

Such light absorption characteristics, for example, in the case of an iodine PVA polarizer, are controlled by the formation of an I3-PVA complex that exhibits absorption at short wavelengths and an I5-PVA complex that exhibits absorption at long wavelengths. Can be reached. The I3-PVA complex and I5-PVA complex are in thermal equilibrium, so they can be controlled by the temperature or I ₂ concentration / KI concentration and drying conditions during dyeing. For example, when the KI concentration is increased, compared with In the case of blue light, the absorption characteristics of red light can be improved. In addition, when the drying temperature is increased, the absorption characteristics of blue light can be improved compared to red light. In the case of a liquid crystal host-guest polarizing plate, the light absorption characteristics can be easily controlled by controlling the amount or ratio of the dichroic pigment added to the guest molecule. For example, when a plurality of pigments are mixed, more blue pigments are blended than other pigments, thereby selectively improving only the absorption characteristics of red light. The elliptical polarizing plate of the present invention is preferably a liquid crystal host-guest polarizing plate from the viewpoint of so-called reproducibility, process stability, and thinness. From the viewpoint of controlling the blending of pigments, the polymer contained in the polarizing plate which is more preferable is obtained by polymerizing the polymerizable liquid crystal compound in a state where the polymerizable liquid crystal compound and the dichroic dye are aligned in a horizontal direction. Polymer.

The iodine PVA polarizing plate can be produced by, for example, a method of successively extending a PVA film in a heated state and then performing iodine dyeing and cross-linking treatment with boric acid; or Simultaneous stretching method in which PVA in the form of a thin film is stretched with iodine dyeing in water and cross-linking treatment with boric acid. The stretching ratio at this time is preferably 4 to 8 times, and can be produced by continuously immersing in an iodine aqueous solution and a boric acid aqueous solution, and impregnating respective molecules in a PVA film. After dyeing, the PVA film is dried, thereby removing water, and performing boric acid crosslinking to obtain a PVA polarizer. As the drying method at this time, it is preferable to carry out the ventilation drying method or the infrared drying method, and the temperature is preferably in the range of 40 ° C to 150 ° C. The temperature is preferably 60 ° C to 130 ° C. The PVA polarizer obtained in this way can be used to protect one or both sides of the PVA polarizer by using the transparent substrate described above, to produce an iodine PVA polarizer.

When a liquid crystal host-guest polarizing plate is used, a dichroic dye is mixed in advance into a layer made of a polymer in an aligned state of a polymerizable liquid crystal compound, so that it can be manufactured in the same way as a retardation plate, but In order to satisfy the aforementioned formulas (6) to (11) at the same time, a high-order liquid crystal structure is required. That is, as the polymerizable liquid crystal compound, a smectic liquid crystal compound is preferable to a nematic liquid crystal compound, and a high-order nematic liquid crystal compound is more preferable. Among them, smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, and smectic J are formed. Phase, smectic K-phase or smectic L-phase high-layer smectic liquid crystal compounds are also preferred to form smectic B-phase, smectic F-phase or smectic I-phase high-tier smectic liquid crystals. Compounds are more preferred. When the liquid crystal phase formed by the polymerizable liquid crystal compound is such a high-order nematic phase, a liquid crystal cured film having a higher degree of alignment order can be manufactured, and high polarization performance can be obtained. In addition, in such a liquid crystal hardened film having a high degree of alignment order, a Bragg peak derived from a high-order structure having a hexagonal phase or an equivalent crystal can be obtained in X-ray diffraction measurement. The Bragg peak is derived from the peaks of the periodic structure of the molecular alignment, and a film with a periodic interval of 3.0 to 6.0 Å can be obtained.

Specific examples of such a compound include a compound represented by the following formula (III) (hereinafter, sometimes referred to as "compound (III)"), and the like, and a polarizing plate constituting the elliptical polarizing plate of the present invention is preferred. by It consists of a polymerizable liquid crystal compound containing a compound (III). These polymerizable liquid crystal compounds may be used alone or in combination of two or more kinds.

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

In formula (III), X ¹ , X ² and X ³ each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the divalent aromatic group or the divalent alicyclic group The hydrogen atom contained in the hydrocarbon group may be substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group. The carbon atom of the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom. However, at least one of X ¹ , X ² and X ³ is 1,4-phenylene which may have a substituent or cyclohexane-1,4-diyl which may have a substituent.

Y ¹ , Y ² , W ¹ and W ² are each independently a single bond or a divalent linking group.

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

U ¹ and U ² each independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

In the compound (III), at least one of X ¹ , X ² and X ³ is 1,4-phenylene which may have a substituent, or cyclohexane-1,4-diyl which may have a substituent. In particular, X ¹ and X ³ are preferably cyclohexane-1,4-diyl which may have a substituent. The cyclohexane-1,4-diyl is trans-cyclohexane-1 , 4-Diyl is more preferred. When a structure including trans-cyclohexane-1,4-diyl group is used, it tends to exhibit smectic liquid crystal properties easily. Examples of the substituent optionally included in the 1,4-phenylene group which may have a substituent or the cyclohexane-1,4-diyl group which may have a substituent include a methyl group, an ethyl group, and a butyl group. And other halogen atoms such as an alkyl group having 1 to 4 carbon atoms, a cyano group, a chlorine atom, and a fluorine atom. It is preferably unsubstituted.

Y ¹ and Y ² are independent of each other, preferably a single bond, -CH ₂ CH _2- , -CH ₂ O-, -COO-, -OCO-, -N = N-, -CR ^a = CR ^b -,- C≡C- or CR ^a = N-, and R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y ¹ and Y ^{2 are} preferably -CH ₂ CH _2- , -COO-, -OCO-, or a single bond, and Y ¹ and Y ² are more preferably different from each other in a bonding manner. When Y ¹ and Y ² are mutually different bonding methods, there is a tendency that smectic liquid crystal properties are easily exhibited.

W ¹ and W ² are preferably independent of each other, preferably a single bond, -O-, -S-, -COO-, or OCO-, and preferably independent of each other as a single bond or -O-.

Examples of the alkanediyl group having 1 to 20 carbon atoms represented by V ¹ and V ² include methylene, ethylene, propane-1,3-diyl, butane-1,3-diyl, and butane. Alkane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, decane Alkane-1,10-diyl, tetradecane-1,14-diyl and eicosane-1,20-diyl, etc. V ¹ and V ^{2 are} preferably an alkyldiyl group having 2 to 12 carbon atoms, and more preferably a linear alkyldiyl group having 6 to 12 carbon atoms. Making a linear alkylene group having 6 to 12 carbon atoms improves crystallinity and tends to exhibit smectic liquid crystal properties easily.

Examples of the optionally substituted substituent having 1 to 20 carbon dialkyl groups which may have a substituent include a cyano group, a halogen atom such as a chlorine atom, a fluorine atom, and the like. Good, unsubstituted and linear Alkyl diyl is more preferred.

It is preferable that U ¹ and U ² are both polymerizable groups, and it is more preferable that they are both photopolymerizable groups. The polymerizable liquid crystal compound having a photopolymerizable group is advantageous from the viewpoint that polymerization can be performed under lower temperature conditions.

The polymerizable groups represented by U ¹ and U ² may be different from each other, but are preferably the same. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, a propenyloxy group, a methacryloxy group, and an ethylene oxide group. , Oxetanyl and the like. Among them, acryloxy, methacryloxy, vinyloxy, ethylene oxide, and oxetanyl are preferred, and acryloxy is preferred.

Examples of such a polymerizable liquid crystal compound include the following.

Among the aforementioned compounds shown in the examples, they are selected from the group consisting of formula (1-2), formula (1-3), formula (1-4), formula (1-6), formula (1-7), formula (1- 8) At least one of the groups formed by the compounds represented by formula (1-13), formula (1-14) and formula (1-15) is preferable.

The so-called dichroic pigment refers to a pigment having a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction.

As a dichroic pigment, those having a maximum absorption wavelength (λ MAX) in the range of 300 to 700 nm are preferred. Examples of such a dichromatic pigment include acridine pigment, oxazine pigment, cyanine pigment, naphthalene pigment, azo pigment, and anthraquinone pigment. Among these, azo pigment is preferred. Examples of the azo pigment include a monoazo pigment, a disazo pigment, a triazo pigment, a tetraazo pigment, and a triazo pigment, and the diazo pigment and the triazo pigment are preferred. The dichroic pigments can be used alone or in combination. It is preferable to combine three or more types of dichroic pigments, and it is also preferable to combine three or more types of azo pigments. By combining three or more types of dichroic pigments (especially in combination 3 or more kinds of azo pigments), and the polarization characteristics can be easily controlled across the entire range of visible light. In addition, when three or more types of dichroic pigments are combined, as compared with other two types of dichroic pigments, a larger amount of dichroic pigments that exhibit absorption at the longest wavelength is used. One means is better.

Examples of the azo pigment include a compound represented by formula (IV) (hereinafter, sometimes referred to as "compound (IV)").

A ¹ (-N = NA ² ) _p -N = NA ³ (IV) [In the formula (IV), A ¹ and A ³ each independently represent a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or A monovalent heterocyclic group which may have a substituent. A ² represents a 1,4-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent heterocyclic group which may have a substituent. p is an integer of 1 to 4. When p is an integer of 2 or more, the complex numbers A ² may be the same or different from each other].

Examples of the monovalent heterocyclic group include quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole after removing one hydrogen atom. base. Examples of the divalent heterocyclic group include a group obtained by removing two hydrogen atoms from the heterocyclic compound.

As phenyl, naphthyl and monovalent heterocyclic groups in A ¹ and A ³ , and 1,4-phenylene, naphthalene-1,4-diyl and divalent heterocyclic groups in A ² Examples of optional substituents include alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, and butyl; alkoxy groups having 1 to 4 carbon atoms such as methoxy, ethoxy, and butoxy. ; Trifluoromethyl and other fluorinated alkyl groups having 1 to 4 carbons; cyano; nitro; halogen atoms such as chlorine and fluorine atoms; substituted amino, diethylamino, and pyrrolidinyl groups Or an unsubstituted amine group (a so-called substituted amine group) means an amine group having one or two alkyl groups having 1 to 6 carbon atoms, or two substituted alkyl groups bonded to each other to form a carbon An amine group of 2 to 8 alkyl groups; the so-called unsubstituted amine group is -NH ₂ ). Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, and a hexyl group. Examples of the alkanediyl group having 2 to 8 carbon atoms include ethylene, propane-1,3-diyl, butane-1,3-diyl, butane-1,4-diyl, and pentane- 1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, etc.

Examples of such an azo pigment include the following.

In the formulae (2-1) to (2-6), B ¹ to B ²⁰ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group. , A substituted or unsubstituted amine group (the definition of a substituted amine group and an unsubstituted amine group is the same as above), a chlorine atom or a trifluoromethyl group.

n1 ~ n4 are integers independently representing 0 ~ 3.

When n1 is 2 or more, the complex B ² can be the same or different, respectively. When n 2 is 2 or more, the complex B ⁶ can be the same or different. When n 3 is 2 or more, the complex B ⁹ can be They are the same or different, respectively. When n4 is 2 or more, the complex B ¹⁴ may be the same or different, respectively.

The liquid crystal host-guest polarizing plate can be produced by the following method, for example. For example, a polymerizable liquid crystal compound and a dichroic dye are optionally diluted with a solvent, and a composition (hereinafter, also referred to as a "composition for forming a polarizing film") is applied to a substrate or a substrate On the alignment film, the solvent can be polymerized after drying the solvent as needed, thereby obtaining A polymer containing the polymerizable liquid crystal compound in an aligned state of a mixture of the polymerizable liquid crystal compound and a dichroic dye. By polymerizing the polymerizable liquid crystal compound while maintaining the orientation of the polymerizable liquid crystal compound and the dichroic dye in the horizontal direction, a liquid crystal cured film can be obtained that maintains the alignment state. The liquid crystal cured film constitutes a host-guest polarizing plate. At this time, in order to obtain higher polarization performance, it is preferred that the polymerizable liquid crystal compound is polymerized with a smectic liquid crystal phase and maintained in an aligned state; and it is also preferred that the smectic liquid crystal phase is maintained and maintained at a high level. Alignment state to polymerize the polymerizable liquid crystal compound. The composition for forming a polarizing film may contain a well-known component such as a solvent, a polymerization initiator, a polymerization inhibitor, a light sensitizer, and a leveling agent. As such a component, a retardation plate related to the foregoing description may be used. The users in the composition for forming an optically anisotropic layer are the same. Regarding the preparation of the composition for forming a polarizing film or the coating method, in principle, the same method as that used in the composition for forming an optically anisotropic layer of a retardation plate described above can be applied. The same can be exemplified for the alignment film (the composition for forming an optical alignment film) used here.

The content of the polymerizable liquid crystal compound in the composition for forming a polarizing film (the total amount if plural types are included) is 100 mass% of the solid content of the composition for forming a polarizing film from the viewpoint of exhibiting liquid crystallinity. The amount is usually 60 to 99 parts by mass, preferably 70 to 95 parts by mass, and still more preferably 75 to 90 parts by mass. In addition, the content of the dichroic pigment (the total amount when plural types are included) is usually 1 from 100 parts by mass of the solid content of the composition for forming a polarizing film from the viewpoint of obtaining good light absorption characteristics. ~ 30 parts by mass, preferably 2 to 20 parts by mass, and more preferably 3 to 15 parts by mass. Here, the solid content means the total amount of components after the solvent is removed from the composition for forming a polarizing film.

The elliptically polarizing plate of the present invention includes a polarizing plate and a retardation plate. For example, the elliptically polarizing plate and the retardation plate can be laminated by interposing an adhesive layer or the like to obtain the elliptically polarizing plate of the present invention.

In one embodiment of the present invention, when the polarizing plate and the retardation plate are laminated, the lamination is performed such that the slow axis (optical axis) of the retardation plate and the absorption axis of the polarizing plate become substantially 45 °. Better.

By laminating the slow axis (optical axis) of the retardation plate and the absorption axis of the polarizing plate at 45 °, the function as an elliptical polarizing plate can be obtained. However, the so-called 45 ° is substantially 45 °, and the range is usually 45 ± 5 °.

The elliptical polarizing plate of the present invention may have a configuration including a conventional general elliptical polarizing plate, or a polarizing plate and a retardation plate. As such a structure, for example, an elliptically polarizing plate may be attached to an adhesive layer (sheet) of a display element such as an organic EL, a polarizing plate, or a surface of a retardation plate to prevent injury or pollution. The protective film used. The elliptically polarizing plate of the present invention can be cut and used in display devices such as an organic EL display device and a liquid crystal display device as needed.

In another embodiment of the present invention, a liquid crystal display device and an organic EL display device including the above-mentioned elliptically polarizing plate can be provided. Such a display device is an elliptically polarizing plate of the present invention that has a color capable of suppressing reflection colors in a full range of visible light wavelengths, and can exhibit good color performance.

[Example]

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

Production of elliptical polarizer

For the production of the retardation plate, "the composition for forming a photo-alignment film" and "the composition containing a polymerizable liquid crystal compound" shown below were used.

(1) Comparative Example 1 [Modulation of composition for forming photo-alignment film]

5 parts of the following photo-alignment material and 95 parts of cyclopentanone (solvent) were mixed, and the obtained mixture was stirred at 80 degreeC for 1 hour, and the composition for photo-alignment film formation was obtained. The following photo-alignment materials were synthesized according to the method described in Japanese Patent Application Laid-Open No. 2013-33248.

[Preparation of composition A containing polymerizable liquid crystal compound]

Mix the following polymerizable liquid crystal compound A (12.0 parts) and leveling agent (0.12 parts, BYK-361N; manufactured by BYK-Chemie), the following polymerization initiator (0.72 parts), and cyclopentanone (100 parts, solvent), a composition A containing a polymerizable liquid crystal compound A can be obtained. The polymerizable liquid crystal compound A is synthesized according to the method described in Japanese Patent Application Laid-Open No. 2010-31223. When the measurement was performed using an ultraviolet-visible spectrophotometer (UV3150; manufactured by Shimadzu Corporation), the maximum absorption wavelength λ max (LC) of the polymerizable liquid crystal compound A was 350 nm.

Polymerizable liquid crystal compound A:

Polymerization initiator: 2-dimethylamino-2-benzyl-1- (4-morpholinylphenyl) butane-1-one (Irgacure369; manufactured by Ciba Specialty Chemicals)

Leveling agent: polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)

[Manufacturing method of retardation plate]

Cycloolefin polymer film (COP; ZF-14; made by Japan Zeon Co., Ltd.) using a corona treatment device (AGF-B10; Kasuga Electric Co., Ltd.) to output 0.3 kW and a processing speed of 3 m / min Treatment was performed once under conditions. The aforementioned composition for forming a photo-alignment film was applied to the surface subjected to corona treatment by a rod coating method, dried at 80 ° C. for 1 minute, and a polarized UV irradiation device (with a polarizer member SPOT attached) was used. CURE SP-7; manufactured by Ushio Electric Co., Ltd.), and subjected to polarized UV exposure at a cumulative light amount of 100 mJ / cm ² to form an alignment film. The thickness of the obtained alignment film was measured using an ellipsometer M-220 (manufactured by JASCO Corporation) to be 100 nm.

Next, the composition A containing the previously prepared polymerizable liquid crystal compound was applied to the alignment film at a speed of 50 mm / sec using a wire of a bar coater set to # 30, and the temperature was 120 ° C. Dry for 1 minute. Thereafter, a high-pressure mercury lamp (Uni CureVB-15201BY-A; manufactured by Ushio Electric Co., Ltd.) was used to irradiate ultraviolet rays from the front side of the coating composition A (in a nitrogen environment, the cumulative light amount at a wavelength of 313 nm: 500 mJ / cm ² ) A retardation plate A including an optically anisotropic layer 1 (a retardation film) is formed. The thickness of the optically anisotropic layer 1 included in the obtained retardation plate A was measured using a laser microscope (LEXT; manufactured by Olympus Co., Ltd.) to be 2.28 μm.

[Measurement of optical characteristics of in-plane retardation value Re (λ)]

In order to measure the in-plane retardation value Re (λ) of the retardation plate A (optical anisotropic layer 1), a sheet-shaped pressure-sensitive adhesive (manufactured by Lintec, acrylic pressure-sensitive adhesive, colorless) Transparent, non-aligned) attached to the optically anisotropic layer 1 side of the optical anisotropy of the retardation plate A produced in the same way, and attached to the glass plate with the above adhesive side (in-plane retardation system) After 450 nm, 550 nm, and 650 nm are 0 (zero)), the cycloolefin polymer film is peeled off and the optically anisotropic layer 1 is transferred to the glass plate to prepare a measurement sample. Using this sample, an in-plane retardation value Re (λ) of a wavelength of 450 nm, a wavelength of 550 nm, and a wavelength of 650 nm was measured by a birefringence measuring device (KOBRA-WR; manufactured by Oji Measurement Co., Ltd.). The results are shown in Table 2.

The value of Re (450) / Re (550) of the pointer of the inverse wavelength dispersion of the retardation plate A in Comparative Example 1 was about 0.82, which was 450/550 = 0.818, which was very close to the theoretical value. The value of Re (550) = 137 nm is very close to the theoretical value of 550/4 = 137.5 nm.

[Polarizer I: Manufacture of Iodine PVA Polarizer]

A 30 μm-thick polyvinyl alcohol film (average degree of polymerization of about 2400, saponification degree of 99.9 mol% or more) was uniaxially stretched to about 5 times by dry stretching, and then kept under tension at a pure temperature of 40 ° C Immerse in water for 40 seconds. After that, the dyeing treatment was performed by immersing in a dyeing aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.044 / 5.7 / 100 at 28 ° C for 30 seconds.

Next, it was immersed in a boric acid aqueous solution having a mass ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100 at 70 ° C. for 120 seconds. Next, after washing with pure water at 8 ° C for 15 seconds, and maintaining a tension of 300N, drying was performed at 60 ° C for 50 seconds, and then at 75 ° C for 20 seconds to obtain polyvinyl alcohol. A 12 μm-thick polarizer with iodine was adsorbed and aligned in the film.

A water-based adhesive was injected between the obtained polarizer and a cellulose triacetate film (TAC, KC4UY, manufactured by Konicaminolta Co., Ltd.), and a nip roll was used for bonding. While maintaining the tension of the obtained sticker at 430 N / m, drying was performed at 60 ° C for 2 minutes to obtain a polarizing plate I having a cycloolefin film as a protective film on one side. The above-mentioned water-based adhesive is added to 100 parts of water, 3 parts of carboxyl modified polyvinyl alcohol (KURARAY POVAL KL318; made by Kuraray), and water-soluble polyamine epoxy resin (Sumirez Resin650; Sumika chemtex). (Strand), 1.5% of an aqueous solution having a solid content concentration of 30%) was prepared.

The light absorption characteristics of the obtained polarizing plate I were measured in the following manner.

Using a device in which a folder with a polarizer is mounted on a spectrophotometer (V-7100; (Japan) Spectroscopy Co., Ltd.), the two-beam method is used to measure the obtained wavelength in the range of 380 to 680 nm in 2 nm steps at 2 nm Absorbance in the transmission direction and absorption direction of the polarizing plate I. Table 1 shows each absorbance at 450 nm, 550 nm, and 650 nm. The absorbance at each wavelength that will affect the reflection hue is A2 (450) = 4.7, A2 (550) = 4.9, A2 (650) = 5.0, which are very neutral hue.

The polarizing plate I and the retardation plate A produced as described above were formed so that the angle (θ) formed by the absorption axis of the polarizing plate I and the slow axis of the retardation plate A was 45 °, and a pressure-sensitive adhesive was used. (Manufactured by Lintec, acrylic pressure-sensitive adhesive, colorless and transparent, no orientation) The elliptically polarizing plate 1 was produced by attaching it. The retardation plate side of the elliptically polarizing plate was further attached to a reflective aluminum substrate (manufacturer: light, product number: HA0323) via a pressure-sensitive adhesive. With respect to this sticker, the light from the C light source was irradiated from the 6 ° direction from the polarizer side, and the reflection spectrum was measured. From the obtained reflection spectrum and the isochromatic function of the C light source, the reflection chromaticity a * in the L * a * b * (CIE) color system is calculated. The results are shown in Table 2. The larger the value of the reflection chromaticity a *, the stronger the redness. Table 2 shows the calculated values of P (λ), and the values of P (450) / P (650) and 1-P (450).

(2) Example 1

A phase including an optically anisotropic layer having a thickness of 2.42 μm was prepared in the same manner as in Comparative Example 1 except that the amount of the solvent when the composition A containing the polymerizable liquid crystal compound was prepared was 95 parts by mass. Gap (Type A). The elliptically polarizing plate 2 was produced by laminating the phase difference plate and the polarizing plate I (which were produced by the same method as Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(3) Example 2

Except that the amount of the solvent when the composition A containing the polymerizable liquid crystal compound was prepared was 91 parts by mass, it was the same as that of Comparative Example 1 described above. Method to produce a retardation plate (type A) including an optically anisotropic layer having a thickness of 2.50 μm. The elliptically polarizing plate 3 was produced by laminating the phase difference plate and the polarizing plate I (which were produced by the same method as in Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(4) Comparative example 2

A phase including an optically anisotropic layer having a thickness of 2.17 μm was prepared in the same manner as in the above-mentioned Comparative Example 1 except that the solvent amount when preparing the composition A containing the polymerizable liquid crystal compound was set to 107 parts by mass. Gap (Type A). The elliptically polarizing plate 4 was produced by laminating the phase difference plate and the polarizing plate I (which were produced by the same method as in Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(5) Embodiment 3

In the composition A containing a polymerizable liquid crystal compound of Comparative Example 1, except that the polymerizable liquid crystal compound A was set to 10.5 parts by mass and the following polymerizable liquid crystal compound B was set to 1.5 parts by mass, and the amount of the solvent was set to 120 parts by mass. To prepare composition B containing a polymerizable liquid crystal compound, The thickness of the wire of the wire rod was set to other than # 30, and a retardation plate B including an optically anisotropic layer having a thickness of 1.93 μm was produced in the same manner as in Comparative Example 1 described above. The elliptically polarizing plate 5 was produced by laminating the phase difference plate and the polarizing plate I (which were produced by the same method as Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

Polymerizable liquid crystal compound B

The polymerizable liquid crystal compound B is Paliocolor LC242 (manufactured by BASF).

(6) Example 4

Except that the amount of the solvent when the composition B containing the polymerizable liquid crystal compound was prepared was 115 parts by mass, and the thickness of the wire rod at the time of coating was # 30, it was produced in the same manner as in Example 3 described above. A retardation plate (type B) including an optically anisotropic layer having a thickness of 2.01 μm. The elliptically polarizing plate 6 was produced by laminating the phase difference plate and the polarizing plate I (which were produced by the same method as Comparative Example 1) in the same procedure as in Comparative Example 1. Calculated in the same manner as in Comparative Example 1 The in-plane retardation value Re (λ) of the obtained retardation plate of the elliptically polarizing plate and the reflection chromaticity a * were obtained. The results are shown in Table 2.

(7) Example 5

Except that the solvent amount when preparing the composition B containing the polymerizable liquid crystal compound was set to 108 parts by mass, and the wire thickness at the time of coating was set to # 30, it was produced in the same manner as in Example 3 described above. A retardation plate (type B) including an optically anisotropic layer having a thickness of 2.14 μm. The elliptically polarizing plate 7 was produced by laminating the phase difference plate and the polarizing plate I (which were produced by the same method as in Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(8) Comparative example 3

It was produced in the same manner as in Example 3 except that the amount of the solvent when preparing the composition B containing the polymerizable liquid crystal compound was 127 parts by mass and the thickness of the wire rod at the time of coating was # 30. A retardation plate (type B) including an optically anisotropic layer having a thickness of 1.86 μm. The elliptically polarizing plate 8 was produced by laminating a retardation plate and a polarizing plate I (which were produced by the same method as in Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(9) Example 6

In the composition A containing a polymerizable liquid crystal compound of Comparative Example 1, except that the polymerizable liquid crystal compound A was 9.5 parts by mass and the polymerizable liquid crystal compound B was 2.5 parts by mass, and the amount of the solvent was adjusted to 105 parts by mass. Composition C containing a polymerizable liquid crystal compound, and the thickness of the wire rod at the time of coating was set to other than # 20, and an optical anisotropy having a thickness of 1.72 μm was produced by the same method as in Comparative Example 1 described above. Layer of phase difference plate C. The same procedure as in Comparative Example 1 was used to laminate the retardation plate and the polarizing plate I (which were produced by the same method as in Comparative Example 1) to produce an elliptically polarizing plate 9. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(10) Example 7

Except that the amount of the solvent when the composition C containing the polymerizable liquid crystal compound was prepared was 100 parts by mass, and the thickness of the wire rod at the time of coating was # 20, it was produced in the same manner as in Example 6 described above. A retardation plate (type C) including an optically anisotropic layer having a thickness of 1.76 μm. The elliptically polarizing plate 10 was produced by laminating a retardation plate and a polarizing plate I (which were produced by the same method as in Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(11) Comparative example 4

It was produced in the same manner as in Example 6 except that the amount of solvent when preparing composition C containing a polymerizable liquid crystal compound was 110 parts by mass, and the thickness of the wire rod during coating was # 20. A retardation plate (type C) including an optically anisotropic layer having a thickness of 1.61 μm. The elliptically polarizing plate 11 was produced by laminating the phase difference plate and the polarizing plate I (which were produced by the same method as in Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(12) Example 8

As the polarizing plate, a polarizing plate II produced by the following method: a host-guest polarizing plate was used.

[Modulation of Composition A for Polarizing Film Formation]

The polymerizable liquid crystal compounds C and D, dichroic dyes A to C, a polymerizable initiator, a leveling agent, and a solvent are mixed as shown below, and the mixture is stirred at 80 ° C for 1 hour to obtain a polarizing film. Composition A. After the composition A for polarizing film formation was applied by spin coating, the solvent-dried film was heated on a hot plate, and the texture was observed with a polarizing microscope. The phase between the liquid phase and the liquid phase shows a crystalline phase (62 ° C) Smectic B phase (76 ℃) Smectic A phase (105 ℃) Nematic phase (114 ℃) Smectic liquid crystal in three liquid crystal phase states.

Polymerizable liquid crystal compound C (30 parts):

Polymerizable liquid crystal compound D (10 parts):

Dichroic pigment A (3.0 parts) λ MAX = 400nm:

Dichroic pigment B (3.0 parts) λ MAX = 520nm:

Dichroic pigment C (4.3 parts) λ MAX = 640nm:

Polymerization initiator: 2-dimethylamino-2-benzyl-1- (4-morpholinylphenyl) butane-1-one (Irgacure369; Ciba Specialty Chemicals) Secretary) (2.4 copies)

Leveling agent: polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) (0.6 parts)

Solvent: toluene (100 parts)

[Manufacturing method of host-guest polarizer]

A cellulose triacetate film (TAC; KC4UY; manufactured by Konicaminolta Co., Ltd.) was subjected to a corona treatment device (AGF-B10; Kasuga Electric Co., Ltd.) at an output of 0.3 kW and a processing speed of 3 m / min. Process 1 time. The composition for photo-alignment film formation using the alignment film prepared in the same manner as in Comparative Example 1 was applied to the surface subjected to corona treatment by a rod coating method, and dried at 80 ° C. for 1 minute. A polarizing UV irradiation device (with a polarizer member SPOT CURE SP-7; manufactured by Ushio Electric Co., Ltd.) was used to perform polarized UV exposure at a cumulative light amount of 100 mJ / cm ² to form an alignment film. The thickness of the obtained alignment film was measured using an ellipsometer M-220 (manufactured by JASCO Corporation) to be 100 nm.

Next, the previously prepared polarizing film-forming composition A was applied to the obtained alignment film with a wire of a bar coater set to # 10 at a speed of 25 mm / sec, and at 120 ° C. Dry for 1 minute. Thereafter, by using a high-pressure mercury lamp (Uni CureVB-15201BY-A; manufactured by Ushio Electric Co., Ltd.), ultraviolet rays were irradiated from the surface side of the coating composition A (in a nitrogen environment, the cumulative light amount at a wavelength of 313 nm: 500 mJ / cm ² ) to form a polarizing plate II. The polymer included in the polarizing plate II is a polymer obtained by polymerizing a polymerizable liquid crystal compound in a state where the polymerizable liquid crystal compound and a dichroic dye are aligned in a horizontal direction. When the thickness of the obtained polymer was measured using a laser microscope (LEXT; manufactured by Olympus), it was 2.10 μm.

The light absorption characteristics of the obtained polarizing plate II were measured in the same manner as in Comparative Example 1. The results are shown in Table 1. The absorbance at each wavelength that will affect the reflection hue is A2 (450) = 1.8, A2 (550) = 2.0, A2 (650) = 3.2, and it is a blue hue.

The polarizing plate II prepared as described above and the retardation plate (type A, thickness of the optically anisotropic layer 2.17 μm) prepared in the same manner as in Comparative Example 2 were aligned with the absorption axis of the polarizing plate II The angle (θ) formed by the slow axis of the retardation plate is 45 °, and an elliptically polarizing plate is produced by attaching it with a pressure-sensitive adhesive (made by Lintec, acrylic pressure-sensitive adhesive). 12. The retardation plate side of the elliptically polarizing plate was further attached to a reflective aluminum substrate (manufacturer: light, product number: HA0323) via a pressure-sensitive adhesive. With respect to this sticker, the light from the C light source was irradiated from the 6 ° direction from the polarizer side, and the reflection spectrum was measured. From the obtained reflection spectrum and the isochromatic function of the C light source, the reflection chromaticity a * in the L * a * b * (CIE) color system is calculated. The results are shown in Table 2. The calculated values of the in-plane retardation values Re (λ) and P (λ), P (450) / P (650), and 1- The values of P (450) are shown in Table 2.

(13) Example 9

By the same procedure as in Example 8, a laminated polarizing plate II (which was produced by the same method as in Example 8) and a retardation plate (type A) produced in the same manner as in Comparative Example 1 were laminated. , The thickness of the optically anisotropic layer is 2.28 μm) to produce an elliptically polarizing plate 13. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were measured in the same manner as in Example 8. Table 2 shows the calculated values of P (λ) and the calculated values of P (450) / P (650) and 1-P (450).

(14) Example 10

By the same procedure as in Example 8, a laminated polarizing plate II (which was produced by the same method as in Example 8) and a retardation plate (type A) produced by the same method as in Example 1 were laminated. , Thickness of the optically anisotropic layer) to produce an elliptically polarizing plate 14. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were measured in the same manner as in Example 8. Table 2 shows the calculated values of P (λ) and the calculated values of P (450) / P (650) and 1-P (450).

(15) Example 11

By the same procedure as in Example 8, a laminated polarizing plate II (which was produced by the same method as in Example 8) and a retardation plate (type B) produced by the same method as in Comparative Example 3 were laminated. , The thickness of the optically anisotropic layer is 1.86 μm) to produce an elliptically polarizing plate 15. With Example 8 In the same manner, the in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were measured. Table 2 shows the calculated values of P (λ) and the calculated values of P (450) / P (650) and 1-P (450).

(16) Example 12

By the same procedure as in Example 8, a laminated polarizing plate II (which was produced by the same method as in Example 8) and a retardation plate (type B made by the same method as in Example 3) were laminated. , The thickness of the optically anisotropic layer is 1.93 μm) to produce an elliptically polarizing plate 16. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were measured in the same manner as in Example 8. Table 2 shows the calculated values of P (λ) and the calculated values of P (450) / P (650) and 1-P (450).

(17) Example 13

By the same procedure as in Example 8, a laminated polarizing plate II (which was produced by the same method as in Example 8) and a retardation plate (type B made by the same method as in Example 4) were laminated. , Thickness of the optically anisotropic layer (2.01 μm), to produce an elliptically polarizing plate 17. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were measured in the same manner as in Example 8. Table 2 shows the calculated values of P (λ) and the calculated values of P (450) / P (650) and 1-P (450).

(18) Example 14

By the same procedure as in Example 8, a laminated polarizing plate II (which was produced by the same method as in Example 8) and a retardation plate (type C) produced by the same method as in Comparative Example 4 were laminated. , Thickness of the optically anisotropic layer (1.61 μm), to produce an elliptically polarizing plate 18. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were measured in the same manner as in Example 8. Table 2 shows the calculated values of P (λ) and the calculated values of P (450) / P (650) and 1-P (450).

(19) Example 15

By the same procedure as in Example 8, a laminated polarizing plate II (which was produced by the same method as in Example 8) and a retardation plate (type C) produced by the same method as in Example 6 were laminated. , Thickness of the optically anisotropic layer) to produce an elliptically polarizing plate 19. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were measured in the same manner as in Example 8. Table 2 shows the calculated values of P (λ) and the calculated values of P (450) / P (650) and 1-P (450).

(20) Example 16

By the same procedure as in Example 8, the laminated polarizing plate II (which was produced by the same method as in Example 8), and the same method as in Example 7 were used. A retardation plate (type C, thickness of the optically anisotropic layer, 1.76 μm) produced by the same method was used to produce an elliptically polarizing plate 20. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were measured in the same manner as in Example 8. Table 2 shows the calculated values of P (λ) and the calculated values of P (450) / P (650) and 1-P (450).

(21) Comparative example 5

In the composition A containing a polymerizable liquid crystal compound of Comparative Example 1, except that the polymerizable liquid crystal compound A was not blended, the polymerizable liquid crystal compound B was set to 12.0 parts by mass, and the amount of the solvent was set to 100 parts by mass. Composition D of the liquid crystal compound, and the thickness of the wire rod at the time of coating was set to other than # 7, and an optically anisotropic layer having a thickness of 0.93 μm was produced in the same manner as in Comparative Example 1 described above. Phase difference plate D. This retardation plate does not satisfy the aforementioned formula (3), and does not have reverse wavelength dispersibility. The elliptically polarizing plate 21 was produced by laminating a phase difference plate and a polarizing plate I (which were produced by the same method as Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptically polarizing plate were calculated in the same manner as in Comparative Example 1. The results are shown in Table 2.

(22) Comparative example 6

Except that the amount of the solvent when preparing the composition D containing the polymerizable liquid crystal compound was set to 100 parts by mass, and the thickness of the wire rod at the time of coating was set to # 9 to A retardation plate (type D, optically anisotropic layer having a thickness of 0.99 μm) having a thickness of 0.99 μm was produced in the same manner as in Comparative Example 5 described above. The elliptically polarizing plate 22 was produced by laminating a retardation plate and a polarizing plate I (which were produced by the same method as in Comparative Example 1) in the same procedure as in Comparative Example 1. The in-plane retardation value Re (λ) of the obtained retardation plate of the elliptically polarizing plate and the reflection chromaticity a * were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

The polarizing plate I is a polarizing plate that is extremely neutral in hue, and the polarizing plate II is a polarizing plate with a blue hue.

The elliptically polarizing plates of Examples 1 to 16 satisfying all of the optical characteristics represented by the following formulae (1) to (4) show that the value of the reflection chromaticity a * is small (a value close to 0) and the reflection The color is very neutral and red is an improved elliptical polarizer.

On the other hand, the elliptically polarizing plates of Comparative Examples 1 to 4 which do not have the optical characteristics represented by the following formula (1) have a large value of reflection chromaticity a *, and are elliptically polarizing plates with red reflection color. In addition, the elliptic polarizing plates of Comparative Examples 5 and 6 that did not satisfy the optical characteristics represented by the formula (3) and did not have inverse wavelength dispersion had a very large value of reflection chromaticity a *, and red, which is a reflection color, was very Strong elliptical polarizer.

0.8 ≦ P (450) / P (650) ≦ 1.2 (1)

P (550) ≧ 0.7 (2)

Re (450) <Re (550) <Re (650) (3)

0.05 <1-P (450) <0.3 (4)

Claims (9)

An elliptically polarizing plate comprising a polarizing plate and a retardation plate, and satisfying all of the following formulae (1) to (4), the retardation plate includes a polymerization obtained by polymerizing a polymerizable liquid crystal compound in an aligned state. Objects, 0.8 ≦ P (450) / P (650) ≦ 1.2 (1) P (550) ≧ 0.7 (2) Re (450) <Re (550) <Re (650) (3) 0.05 <1-P ( 450) <0.3 (4) [In the above formulas (1) to (4), P (λ) = tan {sin ^-1 ((I1 (λ) × sin Π (λ) × sin2 θ-I2 (λ) × sin Π (λ) × cos2 θ ) / I2 (λ)) / 2}, I1 (λ) = (10 -A1 (λ) -10 -A2 (λ)) / 2, I2 (λ) = (10 - ^{A1 (λ)} +10 ^{-A2 (λ)} ) / 2, Π (λ) = Re (λ) / λ × 2 π, P (λ) indicates the elliptical polarization state at the wavelength λ nm, A1 (λ) Is the absorption axis direction of the polarizing plate at the wavelength λ, A2 (λ) is the absorption axis direction of the polarizing plate at the wavelength λ, and Π (λ) is the phase difference of the retardation plate at the wavelength λ , Re (λ) represents the frontal retardation of the retardation plate at the wavelength λ, and θ represents the angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate]. For example, the elliptical polarizing plate of claim 1, wherein the front retardation of the retardation plate at a wavelength of 550 nm satisfies the following formula (5), 130 nm ≦ Re (550) ≦ 150 nm (5) [where, the Re (550) system Indicates the frontal retardation at a wavelength of 550 nm]. For example, the elliptical polarizing plate of claim 1, wherein the absorption axis direction absorbance (A2) of the polarizing plate at the wavelength λ is a total number satisfying the following formulas (6) to (8), 1 ≦ A2 (450) ≦ 6 (6 ) 1 ≦ A2 (550) ≦ 6 (7) 2 ≦ A2 (650) ≦ 6 (8). For example, the elliptical polarizer of claim 1, wherein the transmission axis direction absorbance (A1) of the polarizer at the wavelength λ is all that satisfies the following formulas (9) to (11), 0.001 ≦ A1 (450) ≦ 0.1 (9 ) 0.001 ≦ A1 (550) ≦ 0.1 (10) 0.002 ≦ A1 (650) ≦ 0.2 (11). For example, the elliptical polarizer of claim 1, wherein the absorption axis direction absorbance (A2) of the polarizer at the wavelength λ satisfies the following formulas (12) and (13), and A2 (650)> A2 (450) (12) A2 (650)> A2 (550) (13). For example, the elliptical polarizing plate of claim 1, wherein the angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate is substantially within a range of 45 ° ± 5 °. For example, the elliptical polarizing plate of claim 1, wherein the polymer included in the polarizing plate is a polymer obtained by polymerizing a polymerizable liquid crystal compound in a state where a mixture of a polymerizable liquid crystal compound and a dichroic dye is aligned. A liquid crystal display device includes an elliptical polarizing plate according to any one of claims 1 to 7. An organic EL display device includes an elliptical polarizing plate according to any one of claims 1 to 7.