JP2017167517A - Elliptically polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elliptically polarizing plate capable of minimizing coloring by reflection color over an entire visible ray wavelength range, and of imparting good display characteristics when used for a display device.SOLUTION: An elliptically polarizing plate is provided, which comprises a polarizing plate and a retardation plate and satisfies all of the expressions (1)-(4) below: 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), where I1(λ), I2(λ), and Π(λ) are defined as I1(λ)=(10-10)/2, I2(λ)=(10+10)/2, and Π(λ)=Re(λ)/λ×2π, and A1(λ) represents an absorbance of the polarizing plate in a transmission axis direction at a wavelength λ, A2(λ) represents an absorbance of the polarizing plate in an absorption axis direction at a wavelength λ, Re(λ) represents a frontal retardation at a wavelength λ, and θ represents an angle between the absorption axis of the polarizing plate and a slow axis of the retardation plate.SELECTED DRAWING: None

Description

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

  In flat panel display devices (FPD) such as organic EL display devices, circularly polarizing plates are widely used for the purpose of preventing reflection from outside light. A circularly polarizing plate has a configuration in which a linearly polarizing plate and a retardation plate (λ / 4 plate) are laminated. However, when a general positive wavelength dispersive material is applied as a retardation plate, Since the phase difference of / 4 cannot be expressed, there is a problem that coloring of the reflected color occurs. In order to solve this problem, in Patent Document 1, a reverse wavelength dispersive liquid crystal material designed to reduce birefringence at a short wavelength is used. In Patent Document 2, a reverse wavelength dispersive polymer film material is used. Circular polarizing plates each used as a phase difference plate are disclosed.

Japanese Patent No. 3325560 JP 2014-123134 A

Theoretically, a circularly polarizing plate having no reflection color can be obtained by designing a retardation plate so as to have a retardation of ¼ at wavelengths in the entire visible light range (with reverse wavelength dispersion).
That is, as theoretical values, the retardation Re (450) for substantially blue light 450 nm is 450 ÷ 4 = 112.5 nm, the retardation Re (550) for substantially green light 550 nm is 550 ÷ 4 = 137.5 nm, and the retardation Re for substantially red light 650 nm. By setting (650) to 650 ÷ 4 = 162.5 nm, a circularly polarizing plate having no reflection color can be obtained.

  However, the retardation plates as disclosed in Patent Document 1 and Patent Document 2 can approach the theoretical value for short-wavelength light, but cannot be the theoretical value for long-wavelength light. is there. This is because the reverse wavelength dispersive birefringence as a substantial retardation plate is obtained by subtracting the birefringence at each wavelength of the positive orientation birefringence structure and the negative orientation birefringence structure. This is because the wavelength dispersion cannot be a linear change. In short, this is due to the fundamental principle that the shorter the wavelength, the greater the dispersion / the longer the wavelength, the smaller the dispersion. As a result, when the phase difference plate is designed so that the green light that maximizes the human visibility becomes a theoretical value, there is a problem that the reflection of red light becomes insufficient due to insufficient reflection of red light. .

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

The present invention provides the following preferred embodiments [1] to [10].
[1] An elliptically polarizing plate including a polarizing plate and a retardation plate and satisfying all of 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)
[In the above formulas (1) to (4),
P (λ) = tan {sin ⁻¹ ((I1 (λ) × sinΠ (λ) × sin2θ−I2 (λ) × sinΠ (λ) × cos2θ) / I2 (λ)) / 2},
I1 (λ) = (10− ^{A1 (λ)} −10− ^{A2 (λ)} ) / 2, I2 (λ) = (10− ^{A1 (λ)} + 10− ^{A2 (λ)} ) / 2, and Π (Λ) = Re (λ) / λ × 2π, A1 (λ) represents the absorbance in the transmission axis direction of the polarizing plate at the wavelength λ, and A2 (λ) represents the absorbance in the absorption axis direction of the polarizing plate at the wavelength λ. Re (λ) represents the front 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. ]
[2] The elliptically polarizing plate according to [1], wherein the retardation of the retardation plate at a wavelength of 550 nm satisfies the following formula (5).
130 nm ≦ Re (550) ≦ 150 nm (5)
[In the formula, Re (550) represents frontal retardation at a wavelength of 550 nm. ]
[3] The elliptically polarizing plate according to [1] or [2], wherein the absorbance (A2) in the absorption axis direction at the wavelength λ of the polarizing plate satisfies all of the following formulas (6) to (8).
1 ≦ A2 (450) ≦ 6 (6)
1 ≦ A2 (550) ≦ 6 (7)
2 ≦ A2 (650) ≦ 6 (8)
[4] The elliptically polarizing plate according to any one of the above [1] to [3], wherein the transmission axis direction absorbance (A1) at the wavelength λ of the polarizing plate satisfies all of 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)
[5] The elliptically polarizing plate according to any one of [1] to [4], wherein the absorbance in the absorption axis direction (A2) at the wavelength λ of the polarizing plate satisfies the following formulas (12) and (13).
A2 (650)> A2 (450) (12)
A2 (650)> A2 (550) (13)
[6] The elliptically polarizing plate according to any one of [1] to [5], wherein an angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate is substantially 45 °.
[7] The elliptically polarizing plate according to any one of [1] to [6], wherein the retardation plate is a layer made of a polymer in an alignment state of the polymerizable liquid crystal compound.
[8] The elliptically polarized light according to any one of [1] to [7], wherein the polarizing plate contains a polymer of the polymerizable liquid crystal compound in an alignment state of a mixture containing the polymerizable liquid crystal compound and the dichroic dye. Board.
[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 including the elliptically polarizing plate according to any one of [1] to [8].

  According to the present invention, it is possible to provide an elliptically polarizing plate that can suppress the coloring of reflected colors at wavelengths in the entire visible light range and can impart good display characteristics when used in a display device.

  Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention.

であり、
Ｉ１（λ）＝（１０^{−Ａ１（λ）}−１０^{−Ａ２（λ）}）／２であり、
Ｉ２（λ）＝（１０^{−Ａ１（λ）}＋１０^{−Ａ２（λ）}）／２であり、
Π（λ）＝Ｒｅ（λ）／λ×２π（単位：ラジアン）であり、
Ａ１（λ）は波長λでの偏光板の透過軸方向吸光度を表し、Ａ２（λ）は波長λでの偏光板の吸収軸方向吸光度を表し、Ｒｅ（λ）は波長λでの正面リタデーションを表し、θは偏光板の吸収軸と位相差板の遅相軸の為す角度を表す。
前記式（１）〜（４）を満たすことにより、かかる楕円偏光板は、従来の逆波長分散性位相差の課題であった赤色の光抜けを抑制することができ、表示装置に用いた場合に良好な表示特性を付与し得る楕円偏光板となる。 The elliptically polarizing plate of the present invention includes a polarizing plate and a retardation plate. The elliptically polarizing plate of the present invention has 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)
Meet.
Here, in the formulas (1) to (4),
P (λ) = tan {sin ⁻¹ ((I1 (λ) × sinΠ (λ) × sin2θ−I2 (λ) × sinΠ (λ) × cos2θ) / I2 (λ)) / 2}

And
^{I1 (λ) = (10 -A1} (λ) -10 -A2 (λ)) is a / 2,
^{I2 (λ) = (10 -A1} (λ) +10 -A2 (λ)) is / 2,
Π (λ) = Re (λ) / λ × 2π (unit: radians),
A1 (λ) represents the absorbance in the transmission axis direction of the polarizing plate at the wavelength λ, A2 (λ) represents the absorbance in the absorption axis direction of the polarizing plate at the wavelength λ, and Re (λ) represents the front retardation at the wavelength λ. And θ represents an angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate.
By satisfying the above formulas (1) to (4), the elliptically polarizing plate can suppress red light leakage, which has been a problem of the conventional reverse wavelength dispersive phase difference, and is used for a display device. It becomes an elliptically polarizing plate that can give good display characteristics.

  In the above formulas (1) and (2), P (λ) represents an elliptical polarization state at a wavelength λnm, P (450) is an elliptical polarization state for light having a wavelength of 450 nm, and P (550) is an ellipse for light having a wavelength of 550 nm. A polarization state, P (650), represents an elliptical polarization state with respect to light having a wavelength of 650 nm. Here, A1 (λ) is the absorbance in the transmission axis direction of the polarizing plate at the wavelength λ, A2 (λ) is the absorbance in the absorption axis direction of the polarizing plate at the wavelength λ, and Π (λ) is the wavelength at the wavelength λ. It is the phase difference (dimensional value) of the phase difference plate, and is calculated from the front retardation at the wavelength λ represented by Re (λ). The closer the value of P (λ) is to 1, the closer to a perfect circular polarization state.

  The values of P (450) / P (650) shown in the formula (1) represent circularly polarized states at wavelengths of 450 nm and 650 nm, respectively, and the closer to 1, the more elliptical polarizing plate with the reflected color suppressed. Therefore, when used in a display device, display with good color is achieved. When the value of the formula (1) is less than 0.8, the reflected color tends to be blue-green. When the value of formula (1) exceeds 1.2, the reflected color tends to be red. In the elliptically polarizing plate of the present invention, the value of P (450) / P (650) depends on the display device, but is preferably 0.85 or more, more preferably 0.9 or more, and preferably 1. 15 or less, more preferably 1.1 or less.

When the value of P (λ) is small, the circularly polarized light conversion becomes insufficient, and the antireflection characteristic on the display device is deteriorated. In particular, when the value of P (550) at the wavelength 550 nm having the highest visibility is small, it is difficult to sufficiently suppress light leakage due to reflection. Therefore, the elliptically polarizing plate of the present invention is represented by the above formula (2). It is necessary to satisfy optical characteristics. When the value of P (550) is less than 0.7, the viewer can 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 from the definition formula.
Furthermore, it is preferable that the value of P (λ) of the elliptically polarizing plate of the present invention is 0.7 or more in the entire visible light range so as to exhibit high antireflection characteristics when used in a display device. That is, it is preferable that the values of P (450) at the short wavelength side of visible light and P (650) at the long wavelength side of visible light are 0.7 or more.

  The elliptically polarizing plate of the present invention satisfies the above formula (3) showing reverse wavelength dispersion. Reverse wavelength dispersion is 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. In the elliptically polarizing plate of the present invention, Re (450) / Re (550) ≦ 1 is preferably satisfied, and 0.82 ≦ Re (450) / Re (550) ≦ 0.93 is more preferable.

  In addition, the elliptically polarizing plate of the present invention needs to satisfy the optical characteristics represented by the formula (4) from the viewpoint of optical design of the reverse wavelength dispersion characteristics. The above equation (4) means that the light is in an elliptically polarized state with respect to light having a wavelength of 450 nm, and the value of P (450) is separated from a theoretical value representing a circularly polarized state of 1 within a predetermined range. By doing so, the antireflection performance of blue light can be reduced. In particular, after satisfying the optical characteristics of the formula (4), the value of P (450) / P (650) in the formula (1) is set to 0.8 to 1.2, so that the color tone is good. Display is achieved. In the elliptically polarizing plate of the present invention, the value of 1-P (450) depends on the display device, but is preferably 0.08 or more, more preferably 0.1 or more, preferably 0.26 or less, More preferably, it is 0.24 or less.

P (λ) can be arbitrarily adjusted by controlling the absorption selection characteristics of the polarizing plate, the wavelength dispersion of the retardation plate, and the film thickness. Specifically, for example, in the case of an iodine PVA polarizing plate, the absorption selection characteristic of the polarizing plate can be controlled by the temperature at the time of dyeing, the I ₂ concentration / KI concentration, the drying conditions, and the like. Then, the absorption characteristic of red light is improved as compared with blue light. Further, when the drying temperature is increased, the blue light absorption characteristic is improved as compared with the red light. In the case of a liquid crystal host-guest polarizing plate, the absorption selection characteristic can be controlled by controlling the addition amount and ratio of the dichroic dye that is a guest molecule. For example, when mixing a plurality of dyes, only the red light absorption property can be selectively improved by blending more blue dyes than other dyes. The wavelength dispersion of the retardation plate can be controlled, for example, by mixing a liquid crystal compound exhibiting reverse wavelength dispersion and a liquid crystal compound exhibiting positive dispersion at an arbitrary ratio. Further, the retardation value decreases as the thickness of the retardation plate decreases. If the film thickness is in a controllable range, it is possible to control the retardation value more easily by controlling the film thickness. For example, a liquid crystal compound exhibiting positive wavelength dispersion so as to achieve a desired wavelength dispersion. By mixing the liquid crystal compound exhibiting the reverse wavelength dispersion and adjusting the film thickness of the retardation plate, the value of P (λ) can be easily controlled to a desired value.

  In the present invention, the antireflection property of the elliptically polarizing plate satisfying the above formulas (1) to (4) is, for example, (i) making the front retardation value of the retardation plate larger than the theoretical value, (ii) retardation Separate the wavelength dispersion of the plate from the theoretical value. (Iii) Absorbance of the polarizing plate near the wavelength of 650 nm (red light), other wavelengths such as near the wavelength of 450 nm (blue light) and near the wavelength of 550 nm (green light) It can control by making it larger than the absorptivity in a region. With regard to (i), for example, the front retardation value is a value determined by Δn (λ) × d (Δn: refractive index difference, d: thickness of retardation plate), and thus the liquid crystal constituting the retardation plate. When the composition of the compound or the like is the same, it can be increased by increasing the film thickness.

  The retardation plate that can constitute the elliptically polarizing plate of the present invention is a polymerizable film that exhibits optical anisotropy by coating and orientation of a polymerizable liquid crystal compound, from the viewpoint of easily controlling the thickness reduction and wavelength dispersion. A layer made of a polymer in the alignment state of the liquid crystal compound (hereinafter also referred to as “optically anisotropic layer”) is preferable. 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 an active radical or an acid generated from a photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The thermic liquid crystal may be either a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferred in terms of enabling precise film thickness control. The phase order structure in the thermotropic 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 above-described reverse wavelength dispersion.

In formula (I), Ar represents a divalent aromatic group, and the divalent aromatic group contains at least one of a nitrogen atom, an oxygen atom and a sulfur atom.
G ¹ and G ² each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or carbon. The carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with an alkoxy group, a cyano group or a nitro group of 1 to 4, and an oxygen atom or a sulfur atom Alternatively, it may be substituted with a nitrogen atom.
L ¹ , L ² _, B ¹ and B ² are each independently a single bond or a divalent linking group.
k and l each independently represent an integer of 0 to 3 and satisfy the relationship of 1 ≦ k + 1. Here, when 2 ≦ k + 1, B ¹ and B ² , G ¹ and G ² may be the same or different from each other.
E ¹ and E ² each independently represents an alkanediyl group having 1 to 17 carbon atoms, wherein a hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, The —CH ₂ — contained may be substituted with —O— or —Si—.
P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least one is a polymerizable group.

G ¹ and G ² are each independently preferably a 1,4-phenyl group optionally 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, 1,4-cyclohexyl group optionally 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, more preferably 1,4 substituted with a methyl group A phenyl group, an unsubstituted 1,4-phenyl group, or an unsubstituted 1,4-trans-cyclohexyl group, particularly preferably an unsubstituted 1,4-phenyl group or an unsubstituted 1,4- It is a trans-cyclohexyl group.
In addition, at least one of a plurality of G ¹ and G ² is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² More preferably, it 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 more 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 more preferably a single bond, —O— -, -COO-, or -OCO-.

  k and l are preferably in the range of 2 ≦ k + l ≦ 6 from the viewpoint of expression of inverse wavelength dispersion, preferably k + l = 4, and more preferably k = 2 and l = 2. It is preferable that k = 2 and l = 2 because a symmetrical structure is obtained.

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 an epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, and oxiranyl group. And an oxetanyl group.
Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable.

  Ar preferably has an aromatic heterocycle. Examples of the aromatic heterocycle 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 a phenanthroline ring. . Of these, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazole group is more preferable. In addition, when Ar includes a nitrogen atom, the nitrogen atom preferably has π electrons.

Wherein (I), 2-valent of [pi Total N _[pi electrons contained in the aromatic group preferably 10 or more represented by Ar, more preferably 14 or more, further preferably 18 or more. Moreover, Preferably it is 30 or less, More preferably, it is 26 or less, More preferably, it is 24 or less.

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

In formula (Ar-1) to formula (Ar-20), * represents a linking part, and Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, or an alkyl having 1 to 12 carbon atoms. Group, cyano group, nitro group, alkylsulfinyl group having 1 to 12 carbon atoms, alkylsulfonyl group having 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 6 carbon atoms, C1-C12 alkylthio group, C1-C12 N-alkylamino group, C2-C12 N, N-dialkylamino group, C1-C12 N-alkylsulfamoyl group or carbon The N, N-dialkylsulfamoyl group represented by Formula 2 to 12 is represented.

Q ¹ , Q ² and Q ³ each independently represent —CR ^{2 ′} R ^{3 ′} —, —S—, —NH—, —NR ^{2 ′} —, —CO— or —O—, and 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 represents an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

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

Examples of the aromatic hydrocarbon group for Y ¹ , Y ² and Y ³ include an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group. A naphthyl group is preferred, and a phenyl group is more preferred. The aromatic heterocyclic group has 4 to 20 carbon atoms and contains at least one hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, or a benzothiazolyl group. An aromatic heterocyclic group is mentioned, and a furyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group are preferable.

Y ¹ , Y ² and Y ³ may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aggregate of aromatic rings. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

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. ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

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

Among formulas (Ar-1) to (Ar-20), formula (Ar-6) and formula (Ar-7) are preferred from the viewpoint of molecular stability.
In formulas (Ar-14) to (Ar-20), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . 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. This aromatic heterocyclic group may have a substituent. Y ¹ may be the above-described optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ .

  By aligning such a polymerizable liquid crystal compound to form a polymer in the aligned state of the polymerizable liquid crystal compound, a retardation plate having reverse wavelength dispersion can be produced. In this case, the polymerizable liquid crystal compound may be used alone, or two or more kinds having different molecular structures may be mixed and used. In the present invention, the wavelength dispersibility can be easily controlled in accordance with the polarizing plate constituting the elliptically polarizing plate and the display device incorporating the elliptically polarizing plate, so that two or more kinds of polymerizable liquid crystals having different wavelength dispersibility can be used. It is preferable to mix the compounds. In this case, it is preferable that the polymerizable liquid crystal compound represented by the formula (I) is included as the polymerizable liquid crystal compound to be mixed.

  In one embodiment of the present invention, the retardation plate constituting the elliptically polarizing plate of the present invention has a wavelength dispersion different from that of the polymerizable liquid crystal compound in addition to the polymerizable liquid crystal compound represented by the formula (I). It is preferable to contain other polymerizable liquid crystal compounds having The other polymerizable liquid crystal compound different from the polymerizable liquid crystal compound represented by the formula (I) has a reverse wavelength dispersion having a molecular structure different from that of the polymerizable liquid crystal compound represented by the formula (I). It may be a polymerizable liquid crystal compound or a polymerizable liquid crystal compound exhibiting positive wavelength dispersion. In a preferred embodiment of the present invention, the retardation plate constituting the elliptically polarizing plate of the present invention has a polymerizable property exhibiting positive wavelength dispersion in addition to the polymerizable liquid crystal compound represented by the formula (I). Includes liquid crystal compounds. Thereby, it becomes possible to control the wavelength dispersion of the retardation plate more easily.

  In the present invention, when a polymerizable liquid crystal compound exhibiting positive wavelength dispersion is included as the liquid crystal compound constituting the retardation plate, the structure thereof is not particularly limited, and the positive wavelength generally used in this field A polymerizable liquid crystal compound exhibiting dispersibility can be used. As such a polymerizable liquid crystal compound, for example, a structure represented by the following formula (II) is preferable.

In formula (II), G ¹ , G ² , L ¹ , L ² _, B ¹ , B ² , k, l, E ¹ , E ² , P ¹ , and P ² are the same as in the structural formula (I) G ³ is independently defined in the same manner as G ¹ and G ² .

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

  Specific examples of polymerizable liquid crystal compounds exhibiting positive wavelength dispersion include “3.8.6 Network (completely cross-linked) of Liquid Crystal Handbook (Edited by Liquid Crystal Handbook Editorial Board, published on Mar. 30, 2000)”. Among the compounds described in “Type)” and “6.5. 1 Liquid crystal material b. Polymerizable nematic liquid crystal material”, compounds having a polymerizable group may be mentioned. Moreover, you may use a commercial product as these polymeric liquid crystal compounds.

  As described above, in the present invention, the retardation value of the retardation plate is made larger than the theoretical value, and the wavelength dispersibility of the retardation plate is separated from the theoretical value, whereby the elliptically polarizing plate has the above formula (1). Optical characteristics satisfying (4) can be imparted. Here, in the present invention, “the wavelength dispersion of the retardation plate is separated from the theoretical value” means that R (λ1) / R (λ2) ≈λ1 / λ2 (λ1 <λ2). The wavelength dispersion of the retardation plate can be adjusted by the mixing ratio of the polymerizable liquid crystal compound having reverse wavelength dispersion and the polymerizable liquid crystal compound having positive wavelength dispersion, and the polymerizable liquid crystal compound having positive wavelength dispersion. As the ratio increases, R (λ1) / R (λ2)> λ1 / λ2 (λ1 <λ2). Here, R (λ1) represents the front phase difference value at the wavelength λ1, and R (λ2) represents the front phase difference value at the wavelength λ2. Moreover, the retardation value of a phase difference plate becomes large, so that the ratio of the polymerizable liquid crystal compound which has positive wavelength dispersion property becomes high. Therefore, in the present invention, for example, when a retardation plate is formed by mixing two or more polymerizable liquid crystal compounds including the polymerizable liquid crystal compound represented by the formula (I), the mixing ratio is expressed by the formula: Although it may be appropriately determined depending on the molecular structure of the polymerizable liquid crystal compound represented by (I) and the type of the polymerizable liquid crystal compound to be combined, it is represented by the formula (I) with respect to the total amount of all polymerizable liquid crystal compounds constituting the retardation plate. The ratio of the polymerizable liquid crystal compound to be formed is preferably 50% by mass or more, and more preferably 60% by mass or more.

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

Furthermore, in one embodiment of the present invention, the retardation of the retardation plate at a wavelength of 550 nm is expressed by the following formula (5):
130 nm ≦ Re (550) ≦ 150 nm (5)
It is preferable to satisfy. When the retardation of the retardation plate at the wavelength of 550 nm satisfies the above formula (5), it functions as a so-called quarter wavelength plate. In particular, it is preferable to combine a polarizing plate having good absorption selection characteristics and a retardation plate satisfying the formula (5). By setting it as such a combination, it can be set as the circularly-polarizing plate which has a favorable antireflection characteristic. When combining a polarizing plate and a phase difference plate, it is preferable that each optical axis is substantially 45 °.

In the case of producing a polymer in an alignment state of a polymerizable liquid crystal compound, a composition containing a polymerizable liquid crystal compound diluted with a solvent in some cases on a substrate or an alignment film formed on the substrate ( Hereinafter, the polymer in the alignment state of the polymerizable liquid crystal compound can be obtained by applying “polymerization for forming an optically anisotropic layer”) and optionally polymerizing the solvent after drying.
By polymerizing the polymerizable liquid crystal compound while maintaining the alignment state, a liquid crystal cured film maintaining the alignment state is obtained, and the liquid crystal cured film constitutes a retardation plate.

  In view of increasing the orientation of the polymerizable liquid crystal compound, the content of the polymerizable liquid crystal compound in the composition for forming an optically anisotropic layer (the total amount in the case where a plurality of types are included) is used to form the optically anisotropic layer. Is usually 70 to 99.9 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 97 parts by mass, and still more preferably 85 to 97 parts by mass with respect to 100 parts by mass of the solid content of the composition. 95 parts by mass. In addition, solid content here means the total amount of the component remove | excluding the solvent from the composition for optically anisotropic layer formation.

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

  As the solvent, an organic solvent capable of dissolving the constituent components of the optically anisotropic layer forming composition such as a polymerizable liquid crystal compound is preferable, and the constituent components of the optically anisotropic layer forming composition such as the polymerizable liquid crystal compound are preferably used. A solvent that is soluble and is inert to the polymerization reaction of the polymerizable liquid crystal compound is more preferable. Specifically, alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, phenol; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ- Ester solvents such as butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, and methyl isobutyl ketone; non-chlorinated aliphatic carbonization such as pentane, hexane, and heptane Hydrogen solvents; Non-chlorinated aromatic hydrocarbon solvents such as toluene and xylene; Nitrile solvents such as acetonitrile; Tetrahydrofuran and dimeth Ether solvents such as Shietan; include; and chloroform, chlorinated hydrocarbon solvents such as chlorobenzene. Two or more organic solvents may be used in combination. Among these, alcohol solvents, ester solvents, ketone solvents, non-chlorinated aliphatic hydrocarbon solvents and non-chlorinated aromatic hydrocarbon solvents are preferable.

  The content of the solvent is preferably 10 to 10000 parts by weight, more preferably 100 to 5000 parts by weight, and still more preferably 100 to 2000 parts with respect to 100 parts by weight of the solid content of the composition for forming an optically anisotropic layer. It is. The solid concentration in the composition for forming an optically anisotropic layer is preferably 2 to 50% by mass, more preferably 5 to 50% by mass, and further preferably 5 to 30%.

  The polymerization initiator is a compound capable of initiating a polymerization reaction such as polymerizable liquid crystal. As a polymerization initiator, the photoinitiator which generate | occur | produces a radical by light irradiation is preferable. Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, α-hydroxyketone compounds, α-aminoketone compounds, α-acetophenone compounds, triazine compounds, iodonium salts, and sulfonium salts. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369 (all are manufactured by Ciba Japan Co., Ltd.), Sequol (registered trademark) BZ, Sequol Z , Sequol BEE (all of which are manufactured by Seiko Chemical Co., Ltd.), kayacure (registered trademark) BP100 (manufactured by Nippon Kayaku Co., Ltd.), kayakure UVI-6992 (manufactured by Dow), Adekaoptomer (registered trademark) SP -152, Adekaoptomer SP-170 (all manufactured by ADEKA Corporation), TAZ-A, TAZ-PP (all manufactured by Nippon Siebel Hegner) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.). Of these, α-acetophenone compounds are preferable, and examples of α-acetophenone compounds include 2-methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one, 2-dimethylamino-1- (4-morpholino Phenyl) -2-benzylbutan-1-one, 2-dimethylamino-1- (4-morpholinophenyl) -2- (4-methylphenylmethyl) butan-1-one, and the like, more preferably 2- And methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutan-1-one. Examples of commercially available products of α-acetophenone compounds include Irgacure 369, 379EG, 907 (above, manufactured by BASF Japan Ltd.), Sequol BEE (manufactured by Seiko Chemical Co., Ltd.), and the like.

  Since a photoinitiator can fully utilize energy emitted from a 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 usually 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound in order to polymerize the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound. The amount is preferably 0.5 to 10 parts by mass.

  By blending a polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Polymerization inhibitors include hydroquinones having substituents such as hydroquinone and alkyl ethers; catechols having substituents such as alkyl ethers such as butylcatechol; pyrogallols, 2,2,6,6-tetramethyl-1- And radical scavengers such as piperidinyloxy radicals; thiophenols; β-naphthylamines and β-naphthols.

  The content of the polymerization inhibitor is usually 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound in order to polymerize the polymerizable liquid crystal compound without disturbing the alignment of the polymerizable liquid crystal compound. Yes, preferably 0.5 to 10 parts by mass.

Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracene having a substituent such as anthracene and alkyl ether; phenothiazine; and rubrene.
By using a photosensitizer, the sensitivity of the photopolymerization initiator can be increased. Content of a photosensitizer is 0.1-30 mass parts normally with respect to 100 mass parts of polymeric liquid crystal compounds, Preferably it is 0.5-10 mass parts.

  Examples of the leveling agent include organic modified silicone oil-based, polyacrylate-based and perfluoroalkyl-based leveling agents. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all are manufactured by Toray Dow Corning Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all, Momentive Performance Materials Japan GK) Manufactured), Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (above) All manufactured by Sumitomo 3M Co., Ltd.), MegaFace (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482, F-482 (all of which are manufactured by DIC Corporation), Ftop (trade name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.), Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH -40, SA-100 (all are manufactured by AGC Seimi Chemical Co., Ltd.), trade names E1830, E5844 (manufactured by Daikin Fine Chemical Laboratory), BM-1000, BM-1100, BYK-352, B K-353 and BYK-361N (both trade name: BM Chemie Co., Ltd.), and the like. Two or more leveling agents may be combined.

By using a leveling agent, a smoother optically anisotropic layer can be formed.
In addition, in the production process of the retardation plate, the fluidity of the composition for forming an optically anisotropic layer can be controlled, and the crosslinking density of the retardation plate can be adjusted. Content of a leveling agent is 0.1-30 mass parts normally with respect to 100 mass parts of polymeric liquid crystal compounds, Preferably it is 0.1-10 mass parts.

<Application of optical anisotropic layer forming composition>
When producing a polymer in the alignment state of the polymerizable liquid crystal compound, a composition for forming an optically anisotropic layer is applied on a substrate or an alignment film formed on the substrate. A resin base material is preferred. The resin substrate is usually a transparent resin substrate. The transparent resin base material means a base material having translucency capable of transmitting light, particularly visible light, and the translucency is a transmittance of 80% or more with respect to a light beam having a wavelength of 380 nm to 780 nm. The characteristic which becomes. As the resin substrate, a film is usually used, and a long film roll is preferably used.

  Examples of the resin constituting the substrate include polyolefins such as polyethylene, polypropylene, and norbornene polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid ester; polyacrylic acid ester; cellulose ester; polyethylene naphthalate; Polyether sulfone; polyether ketone; polyphenylene sulfide; and polyphenylene oxide. Among them, a substrate made of polyolefin such as polyethylene, polypropylene, norbornene-based polymer is preferable.

  The thickness of a base material is 5-300 micrometers normally, Preferably it is 20-200 micrometers. Moreover, the further film-thinning effect is acquired by peeling a base material and transferring only the polymer in the orientation state of a polymerizable liquid crystal compound.

An alignment film may be formed on the surface of the substrate on which the composition for forming an optically anisotropic layer is applied. The alignment film has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction.
The alignment film has solvent resistance that does not dissolve when the composition for forming an optically anisotropic layer is applied, and has heat resistance in heat treatment for removal of the solvent and alignment of the polymerizable liquid crystal compound described below. Those are preferred. Examples of the alignment film include an alignment film containing an alignment polymer, a photo-alignment film, and a groove alignment film having a concavo-convex pattern and a plurality of grooves on the surface.

  Such an alignment film facilitates the alignment of the polymerizable liquid crystal compound. Further, various orientations such as horizontal orientation, vertical orientation, hybrid orientation, and tilt orientation can be controlled depending on the type of the orientation film and rubbing conditions. The value of the front retardation can be controlled by horizontally aligning the rod-like liquid crystal compound or by vertically aligning the disc-like liquid crystal compound.

  The thickness of the alignment film is usually in the range of 10 to 10000 nm, preferably in the range of 10 to 1000 nm, and more preferably in the range of 50 to 200 nm.

  When the orientation polymer is included, examples of the orientation polymer include polyamides and gelatins having an amide bond, polyimides having an imide bond and polyamic acid that is a hydrolyzate thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, Examples include polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylic acid esters. Among these, polyvinyl alcohol is preferable. Two or more kinds of orientation polymers may be combined.

  An alignment film containing an alignment polymer is usually formed by applying an alignment polymer composition in which an alignment polymer is dissolved in a solvent to a substrate and removing the solvent to form a coating film, or based on the alignment polymer composition. It is obtained by applying to a material, removing the solvent to form a coating film, and rubbing the coating film.

  The concentration of the orienting polymer in the orienting polymer composition may be in a range where the orienting polymer is completely dissolved in the solvent. The content of the orientation polymer with respect to the orientation polymer composition is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass.

  Oriented polymer compositions are commercially available. Examples of the commercially available oriented polymer composition include Sanever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optmer (registered trademark, manufactured by JSR).

  Examples of the method for applying the orientation polymer composition to the substrate include the same methods as those for applying the optically anisotropic layer forming composition described later to the substrate. Examples of the method for removing the solvent contained in the oriented polymer composition include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method.

  The coating film formed from the orientation polymer composition may be rubbed. By performing the rubbing treatment, an alignment regulating force can be imparted to the coating film.

  Examples of the rubbing treatment include a method in which a rubbing cloth is wound and the coating film is brought into contact with a rotating rubbing roll. If masking is performed when the rubbing treatment is performed, a plurality of regions (patterns) having different orientation directions can be formed in the alignment film.

  For the photo-alignment film, usually, a composition for forming a photo-alignment film containing a polymer or monomer having a photoreactive group and a solvent is applied to a substrate, and after removing the solvent, polarized light (preferably, polarized UV) is irradiated. Can be obtained. The photo-alignment film can arbitrarily control the direction of the alignment regulating force by selecting the polarization direction of the polarized light to be irradiated.

  The photoreactive group refers to a group that generates alignment ability when irradiated with light. Specific examples include groups that are involved in photoreactions that are the origin of alignment ability, such as alignment-induced reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, or photodecomposition reactions of molecules generated by light irradiation. As the photoreactive group, an unsaturated bond, particularly a group having a double bond is preferable, and a carbon-carbon double bond (C = C bond), a carbon-nitrogen double bond (C = N bond), and nitrogen-nitrogen. A group having at least one selected from the group consisting of a double bond (N═N bond) and a 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 polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C═N bond include groups having a structure such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N═N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C═O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a halogenated alkyl group.

  A group involved in the photodimerization reaction or the photocrosslinking reaction is preferable in that it has excellent orientation. Among them, a photoreactive group involved in the photodimerization reaction is preferable, and a cinnamoyl group is preferable in that a photoalignment film having a relatively small amount of polarized light irradiation necessary for alignment and having excellent thermal stability and stability over time can be easily obtained. And chalcone groups are preferred. As the polymer having a photoreactive group, a polymer having a cinnamoyl group in which the terminal portion of the polymer side chain has a cinnamic acid structure is particularly preferable.

  The content of the polymer or monomer having a photoreactive group in the composition for forming a photoalignment film can be adjusted by the kind of the polymer or monomer and the thickness of the target photoalignment film, and is at least 0.2% by mass or more. Preferably, the range of 0.3 to 10% by mass is more preferable. As long as the characteristics of the photo-alignment film are not significantly impaired, the composition for forming a photo-alignment film may contain a polymer material such as polyvinyl alcohol or polyimide, or a photosensitizer.

  Examples of the method for applying the composition for forming a photo-alignment film to the substrate include the same methods as those for applying the composition for forming an optically anisotropic layer described later to the substrate. Examples of the method for removing the solvent from the applied composition for forming a photo-alignment film include the same method as the method for removing the solvent from the oriented polymer composition.

  In order to irradiate polarized light, even in the form of irradiating polarized light directly from the composition for forming a photo-alignment film applied on the substrate to which the solvent is removed, the polarized light is irradiated from the substrate side. It is also possible to irradiate through the material. The polarized light is preferably substantially parallel light. The wavelength of the polarized light to be irradiated should be in a wavelength range where the photoreactive group of the polymer or monomer having the photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) in the wavelength range of 250 nm to 400 nm is particularly preferable. Examples of the light source for irradiating the polarized light include xenon lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and the like. Among these, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, and a metal halide lamp are preferable because of high emission intensity of ultraviolet rays having a wavelength of 313 nm. By irradiating light from the light source through an appropriate polarizing layer, polarized UV can be irradiated. Examples of the polarizing layer include polarizing prisms such as polarizing filters, Glan Thompson, and Grand Taylor, and wire grid type polarizing layers.

<Application of optical anisotropic layer forming composition>
A composition for forming an optically anisotropic layer is applied onto the substrate or the alignment film. Examples of the method for applying the composition for forming an optically anisotropic layer on a substrate include extrusion coating, direct gravure coating, reverse gravure coating, CAP coating, slit coating, and die coating. Moreover, the method of apply | coating using coaters, such as a dip coater, a bar coater, a spin coater, etc. are mentioned. Among these, a CAP coating method, an inkjet method, a dip coating method, a slit coating method, a die coating method, and a coating method using a bar coater are preferable because they can be continuously applied in the Roll to Roll format. In the case of coating in the Roll to Roll format, a composition for forming a photo-alignment film or the like is applied to a substrate to form an alignment film, and the composition for forming an optical anisotropic layer is continuously formed on the obtained alignment film. It can also be applied.

<Drying of optical anisotropic layer forming composition>
Examples of the drying method for removing the solvent contained in the composition for forming an optically anisotropic layer include natural drying, ventilation drying, heat drying, reduced pressure drying, and a combination thereof. Of these, 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 still more preferably in the range of 60 to 170 ° C. The drying time is preferably 10 seconds to 20 minutes, 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, photopolymerization is preferred as a method for polymerizing the polymerizable liquid crystal compound. Photopolymerization is carried out by irradiating an active energy ray to a laminate in which a composition for forming an optically anisotropic layer containing a polymerizable liquid crystal compound is applied on a substrate or an alignment film. The active energy rays to be irradiated include the type of polymerizable liquid crystal compound contained in the dry film (particularly, the type of photopolymerizable functional group of the polymerizable liquid crystal compound), and a photopolymerization initiator when it contains a photopolymerization initiator. Depending on the type and amount thereof, it is appropriately selected. Specific examples include 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. Among them, ultraviolet light is preferable in that it is easy to control the progress of the polymerization reaction and that a photopolymerization apparatus widely used in this field can be used. It is preferable to select the kind of the liquid crystalline compound.

  When the composition for forming an optically anisotropic layer contains a photopolymerization initiator, it is preferable to select the type of photopolymerization initiator so that it can be photopolymerized by ultraviolet light.

  Examples of the light source of the active energy ray include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, and a wavelength range. Examples include LED light sources that emit light of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, and the like.

The time for irradiating light is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 1 minute, more preferably 0.1 seconds to 30 seconds, and further preferably 0.1 seconds. 10 seconds.
If it is the said range, the optically anisotropic layer excellent in transparency can be obtained.

  In the present invention, the retardation value of the retardation film can be controlled by adjusting the film thickness of the retardation film. If the composition constituting the retardation plate is the same, the retardation value increases by increasing the film thickness. In addition, when the elliptically polarizing plate is composed of a combination of a retardation plate having the same composition as a polarizing plate having the same composition, by increasing the film thickness of the retardation plate, the elliptical polarizing plate represented by P in the above formula (1) can be obtained. The value of (450) / P (650) can be reduced. The thickness of the retardation plate (optically anisotropic layer) of the present invention can be appropriately determined so as to obtain a desired retardation value depending on the type of polymerizable liquid crystal compound constituting the retardation plate, etc. 0.1 to 5 μm is preferable, 0.5 to 4 μm is more preferable, and 1 to 3 μm is even more preferable. The film thickness can be controlled, for example, by adjusting the amount of the solvent contained in the optically anisotropic layer forming composition or the thickness of the coating film made of the optically anisotropic layer forming composition. The coating thickness can be changed, for example, by changing the wire thickness of the wire bar during application, adjusting the discharge rate with a die coater, or changing the groove depth or peripheral speed with a micro gravure coater. Can be adjusted.

  The elliptically polarizing plate of the present invention includes at least one polarizing plate. The polarizing plate has a function of extracting linearly polarized light from incident natural light. As a specific example of a polarizing plate, a PVA polarizer in which a dichroic dye such as iodine or a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol resin film (PVA) is provided on one side with a polymer film (protective film). Or the polarizing plate which protected both surfaces is mentioned. At this time, for example, a transparent resin film is used as the protective film, and as the transparent resin, an acetyl cellulose resin typified by triacetyl cellulose or diacetyl cellulose, a methacrylic resin typified by polymethyl methacrylate, or a polyester. Examples thereof include resins, polyolefin resins, polycarbonate resins, polyether ether ketone resins, and polysulfone resins. A liquid crystal host guest polarizing plate can also be used. As a liquid crystal host guest type polarizing plate, what is illustrated by Unexamined-Japanese-Patent No. 2012-58381, Unexamined-Japanese-Patent No. 2013-37115, international publication 2012/147633, international publication 2014/091921, for example can be used. Although the thickness of a polarizer is not specifically limited, What is 0.5-35 micrometers normally is used.

  The polarizing plate is a film provided with polarization absorption selectivity by orienting iodine or a dichroic dye in stretched PVA or oriented liquid crystal. The major axis direction of iodine-PVA complex or dichroic dye is called the absorption axis, and the minor axis direction of iodine-PVA complex or dichroic dye is called the transmission axis. By passing completely linearly polarized light produced by a prism or the like in parallel with the absorption axis / transmission axis, each absorbance can be measured from the light intensity before and after the passage. As described above, in the present invention, the optical characteristics of the elliptically polarizing plate can be controlled by controlling the absorption characteristics of the polarizing plate. For example, in an elliptically polarizing plate configured using a retardation plate having the same composition, absorption at a wavelength of about 650 nm (red light) rather than absorption at a wavelength of about 450 nm (blue light) or a wavelength of about 550 nm (green light). By using a highly polarizing plate (a polarizing plate with a more bluish hue), the value of P (450) / P (650) in the above-mentioned formula (1) of this elliptically polarizing plate can be reduced. In particular, since the elliptically polarizing plate of the present invention satisfies the optical properties of the above formulas (1), (2), and (4), the absorbance of the polarizing plate can be controlled.

Specifically, it is preferable that the absorbance (A2) in the absorption axis direction of the polarizing plate satisfies all of the following formulas (6) to (8).
1 ≦ A2 (450) ≦ 6 (6)
1 ≦ A2 (550) ≦ 6 (7)
2 ≦ A2 (650) ≦ 6 (8)
When the polarizing plate has optical characteristics satisfying the above formulas (6) to (8), good light absorption characteristics in the entire visible light region can be obtained.

Moreover, it is preferable that the light absorbency (A1) of the polarizing plate in the transmission axis direction 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)
When the polarizing plate has optical characteristics satisfying the above formulas (9) to (10), good light transmission characteristics in the entire visible light range can be obtained.

Furthermore, in order to increase the absorption of red light near the wavelength of 650 nm, it is more preferable that the absorbance (A2) in the absorption axis direction of the polarizing plate satisfies the following formulas (12) and (13).
A2 (650)> A2 (450) (12)
A2 (650)> A2 (550) (13)
Since the polarizing plate has optical characteristics satisfying the above formulas (12) and (13), it is possible to effectively suppress the reflection of red light, and the reflected color at wavelengths in the entire visible light region including red light. When this is used in a display device, it becomes an elliptically polarizing plate that can give good display characteristics.

For example, in the case of an iodine PVA polarizing plate, such light absorption characteristics are achieved by controlling the formation of an I3-PVA complex exhibiting absorption at a short wavelength and an I5-PVA complex exhibiting absorption at a long wavelength. The Since the I3-PVA complex and the I5-PVA complex are in a thermal equilibrium state, they can be controlled by the dyeing temperature, I ₂ concentration / KI concentration, and drying conditions. For example, when the KI concentration is increased, the blue color The absorption characteristic of red light is improved as compared with light. Further, when the drying temperature is increased, the blue light absorption characteristic is improved as compared with the red light. In the case of a liquid crystal host-guest polarizing plate, the light absorption characteristics can be easily controlled by controlling the addition amount and ratio of the dichroic dye that is a guest molecule. For example, when mixing a plurality of dyes, only the red light absorption property can be selectively improved by blending more blue dyes than other dyes. In the elliptically polarizing plate of the present invention, it is more preferable to use a liquid crystal host guest type polarizing plate from the viewpoint of reproducibility, process stability, and thickness reduction. In addition, a polarizing plate including a polymer obtained by polymerizing the polymerizable liquid crystal compound in a state where the polymerizable liquid crystal compound and the dichroic dye are aligned in the horizontal direction is more advantageous in that the blending of the dye can be controlled. preferable.

  The iodine PVA polarizing plate is, for example, a sequential stretching method in which a PVA in a film form is stretched in a heated state and then subjected to a crosslinking treatment with iodine staining and boric acid, or a crosslinking treatment with iodine staining and boric acid in water. It can be produced by a simultaneous stretching method in which a film-form PVA is stretched. In this case, the draw ratio is preferably 4 to 8 times, and it is produced by continuously immersing in an aqueous iodine solution and an aqueous boric acid solution and impregnating each molecule in a PVA film. By drying the PVA film after dyeing, a PVA polarizer can be obtained by removing moisture and proceeding with boric acid crosslinking. In this case, the drying method is preferably carried out by a ventilation drying method or an infrared drying method, and the temperature is preferably in the range of 40 ° C to 150 ° C, more preferably 60 ° C to 130 ° C. An iodine PVA polarizing plate can be produced by adhering and protecting one side or both sides of the PVA polarizer thus obtained using the transparent substrate described above.

  When using a liquid crystal host-guest type polarizing plate, it can be produced in the same manner as a phase difference plate by mixing a dichroic dye in advance in a layer made of a polymer in the alignment state of the polymerizable liquid crystal compound. However, in order to satisfy the expressions (6) to (11) at the same time, it is necessary to have a highly ordered liquid crystal structure. That is, as the polymerizable liquid crystal compound, a smectic liquid crystal compound is preferable to a nematic liquid crystal compound, and a higher-order smectic liquid crystal compound is more preferable. Among them, higher-order smectic liquid crystal compounds that form a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, or a smectic L phase. More preferred are higher-order smectic liquid crystal compounds that form a smectic B phase, a smectic F phase, or a smectic I phase. When the liquid crystal phase formed by the polymerizable liquid crystal compound is such a high-order smectic phase, a cured liquid crystal film having a higher degree of alignment order can be produced, and high polarization performance can be obtained. In addition, such a liquid crystal cured film having a high degree of orientational order can obtain a Bragg peak derived from a higher order structure such as a hexatic phase or a crystal phase in X-ray diffraction measurement. The Bragg peak is a peak derived from a periodic structure of molecular orientation, and a film having a periodic interval of 3.0 to 6.0 mm 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 constitutes the elliptically polarizing plate of the present invention. The polarizing plate is preferably composed of a polymerizable liquid crystal compound containing compound (III). These polymerizable liquid crystal compounds may be used alone or in combination of two or more.

^{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, wherein the divalent aromatic group or divalent alicyclic group The hydrogen atom contained in the hydrocarbon group is substituted with 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 constituting the divalent aromatic group or 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 a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. It is.
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 optionally substituted alkanediyl group having 1 to 20 carbon atoms, and —CH ₂ — constituting the alkanediyl group is —O—, — S- or NH- may be substituted.
U ¹ and U ² each independently represent a polymerizable group or a hydrogen atom, and at least one is a polymerizable group.

In compound (III), at least one of X ¹ , X ² and X ³ may be a 1,4-phenylene group which may have a substituent, or cyclohexane which may have a substituent. 1,4-diyl group. In particular, X ¹ and X ³ are preferably an optionally substituted cyclohexane-1,4-diyl group, and the cyclohexane-1,4-diyl group is trans-cyclohexane- More preferably, it is a 1,4-diyl group. When the structure of trans-cyclohexane-1,4-diyl group is included, smectic liquid crystallinity tends to be easily developed. In addition, the substituent that the 1,4-phenylene group that may have a substituent or the cyclohexane-1,4-diyl group that may have a substituent optionally has a methyl group , An alkyl group having 1 to 4 carbon atoms such as an ethyl group and a butyl group, a cyano group, and a halogen atom such as a chlorine atom and a fluorine atom. Preferably it is unsubstituted.

Y 1 and Y 2 each independently represent a single bond, —CH 2 CH 2 —, —CH 2 O—, —COO—, —OCO—, —N═N—, —CR a ═CR b —, — C≡C— or CR a ═N— is preferable, 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, -CH 2 CH 2 -, - COO -, - OCO- or more preferable to be a single bond, and more preferably Y 1 and Y 2 are different coupling method together. When Y 1 and Y 2 are different from each other, smectic liquid crystal properties tend to be easily exhibited.

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

Examples of the alkanediyl group having 1 to 20 carbon atoms represented by V ¹ and V ² include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, and a butane-1,4. -Diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, decane-1,10-diyl group, tetradecane -1,14-diyl group and icosane-1,20-diyl group. V ¹ and V ² are preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably a linear alkanediyl group having 6 to 12 carbon atoms. By using a straight-chain alkanediyl group having 6 to 12 carbon atoms, crystallinity is improved and smectic liquid crystallinity tends to be easily exhibited.
Examples of the substituent that the alkanediyl group having 1 to 20 carbon atoms which may have a substituent optionally include a cyano group and a halogen atom such as a chlorine atom and a fluorine atom. The alkanediyl group includes It is preferably unsubstituted, and more preferably an unsubstituted and linear alkanediyl group.

U ¹ and U ² are both preferably a polymerizable group, more preferably a photopolymerizable group. The polymerizable liquid crystal compound having a photopolymerizable group is advantageous in that it can be polymerized under a lower temperature condition.

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, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable.

Examples of such polymerizable liquid crystal compounds include the following.

  Among the exemplified compounds, Formula (1-2), Formula (1-3), Formula (1-4), Formula (1-6), Formula (1-7), Formula (1-8), Formula At least one selected from the group consisting of compounds represented by (1-13), formula (1-14) and formula (1-15) is preferred.

A dichroic dye refers to a dye having the property that the absorbance in the major axis direction of a molecule is different from the absorbance in the minor axis direction.
As the dichroic dye, those having an absorption maximum wavelength (λMAX) in the range of 300 to 700 nm are preferable. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes and anthraquinone dyes, and among them, azo dyes are preferable. Examples of the azo dye include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, and bisazo dyes and trisazo dyes are preferable. The dichroic dyes may be used alone or in combination, but it is preferable to combine three or more kinds of dichroic dyes, and it is more preferable to combine three or more kinds of azo dyes. By combining three or more kinds of dichroic dyes, particularly three or more kinds of azo dyes, the polarization characteristics can be easily controlled over the entire visible light range. Moreover, when combining three or more types of dichroic dyes, it is possible to use more dichroic dyes that absorb at the longest wavelength than the other two types of dichroic dyes. It is preferable as one means.

Examples of the azo dye include a compound represented by formula (IV) (hereinafter sometimes referred to as “compound (IV)”).
_{^{A 1 (-N = N-A}} 2) p -N = N-A 3 (IV)
[In the formula (IV),
A ¹ and A ³ are, independently of one another, which may have a substituent phenyl group, 1 may have a naphthyl group or a substituted group which may have a substituent monovalent heterocyclic group Represents. A ² is a 1,4-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent which may have a substituent. Represents a heterocyclic group. p represents an integer of 1 to 4. When p is an integer greater than or equal to ² , several A2 may mutually be same or different. ]

  Examples of the monovalent heterocyclic group include groups in which one hydrogen atom has been removed from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole and benzoxazole. Examples of the divalent heterocyclic group include groups in which two hydrogen atoms have been removed from the heterocyclic compound.

Phenyl group in A ¹ and ^{A 3,} a naphthyl group and a monovalent heterocyclic group, and substituted 1,4-phenylene group in ^{A 2,} naphthalene-1,4-diyl group and divalent heterocyclic group has optionally The group includes an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group; an alkoxy group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group and a butoxy group; and a carbon number such as a trifluoromethyl group. 1 to 4 fluorinated alkyl groups; a cyano group; a nitro group; a halogen atom such as a chlorine atom or a fluorine atom; a substituted or unsubstituted amino group such as an amino group, a diethylamino group, or a pyrrolidino group. An amino group having one or two alkyl groups having 1 to 6 alkyl groups, or two substituted alkyl groups bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms. Refers to an amino group forms. Unsubstituted amino group is -NH _2.) It can be mentioned. In addition, as a C1-C6 alkyl group, a methyl group, an ethyl group, a hexyl group, etc. are mentioned. Examples of the alkanediyl group having 2 to 8 carbon atoms include ethylene group, propane-1,3-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group. Hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group and the like.

  Examples of such azo dyes include the following.

In formulas (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, a nitro group, a substituted or unsubstituted amino group (a substituted amino group and The definition of an unsubstituted amino group is as described above, and represents a chlorine atom or a trifluoromethyl group.
n1 to n4 each independently represents an integer of 0 to 3.
When n1 is 2 or more, the plurality of B ² may be the same or different,
When n2 is 2 or more, the plurality of B ⁶ may be the same or different,
When n3 is 2 or more, the plurality of B ⁹ may be the same or different,
When n4 is 2 or more, the plurality of B ¹⁴ may be the same or different.

  A liquid crystal host guest type polarizing plate can be produced, for example, by the following method. For example, a composition containing a polymerizable liquid crystal compound and a dichroic dye, optionally diluted with a solvent, on a substrate or an alignment film formed on the substrate (hereinafter referred to as “polarizing film forming composition”). The polymer of the polymerizable liquid crystal compound in the alignment state of the mixture containing the polymerizable liquid crystal compound and the dichroic dye can be obtained by applying a polymer after drying the solvent if necessary. . By polymerizing the polymerizable liquid crystal compound while maintaining the state in which the polymerizable liquid crystal compound and the dichroic dye are aligned in the horizontal direction, a cured liquid crystal film maintaining the aligned state can be obtained. Forming a polarizing plate; In this case, in order to obtain high polarization performance, it is preferable to polymerize the polymerizable liquid crystal compound while maintaining the alignment state in the smectic liquid crystal phase, and to polymerize the polymerizable liquid crystal compound while maintaining the alignment state in the higher order smectic liquid crystal phase. It is more preferable. In addition, the composition for forming a polarizing film may contain known components such as a solvent, a polymerization initiator, a polymerization inhibitor, a photosensitizer, and a leveling agent. The thing similar to what is used in the composition for optically anisotropic layer formation demonstrated to (1) is mentioned. In addition, for the preparation of the polarizing film-forming composition and the coating method thereof, in principle, the same method as that used in the optically anisotropic layer-forming composition described above with respect to the retardation plate can be applied. The same can be exemplified for the alignment film (composition for forming a photo alignment film) and the like used here.

  The content of the polymerizable liquid crystal compound in the composition for forming a polarizing film (the total amount in the case where a plurality of types are included) is 100 parts by mass of the solid content of the composition for forming a polarizing film from the viewpoint of liquid crystal expression. Usually, it is 60-99 mass parts, Preferably it is 70-95 mass parts, More preferably, it is 75-90 mass parts. In addition, the content of the dichroic dye (the total amount when there are a plurality of types) is usually 1 with respect to 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. It is -30 mass parts, Preferably it is 2-20 mass parts, More preferably, it is 3-15 mass parts. In addition, solid content here means the total amount of the component remove | excluding the solvent from the composition for polarizing film formation.

The elliptically polarizing plate of the present invention includes a polarizing plate and a retardation plate. For example, the elliptically polarizing plate of the present invention is formed by laminating a polarizing plate and a retardation plate via an adhesive layer or the like. A board can be obtained.
In one embodiment of the present invention, when the polarizing plate and the retardation plate are laminated, the lamination is performed so that the slow axis (optical axis) of the retardation plate and the absorption axis of the polarizing plate are substantially 45 °. It is preferable to do.
By laminating so that the slow axis (optical axis) of the retardation plate of the present invention and the absorption axis of the polarizing plate are substantially 45 °, the function as an elliptically polarizing plate can be obtained. Note that substantially 45 ° is usually in the range of 45 ± 5 °.

  The elliptically polarizing plate of the present invention may have a configuration provided in a conventional general elliptically polarizing plate or a polarizing plate and a retardation plate. As such a configuration, for example, an adhesive layer (sheet) for bonding an elliptically polarizing plate to a display element such as an organic EL, or the like is used for the purpose of protecting the surface of a polarizing plate or a retardation plate from scratches and dirt. A protective film. Further, the elliptically polarizing plate of the present invention can be cut as necessary and used for display devices such as organic EL display devices and liquid crystal display devices.

  In another embodiment of the present invention, a liquid crystal display device and an organic EL display device including the elliptically polarizing plate can be provided. These display devices can exhibit good color expression by including the elliptically polarizing plate of the present invention that can suppress the coloring of the reflected color at wavelengths in the entire visible light range.

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

Production of Elliptically Polarizing Plate The following “photoalignment film-forming composition” and “composition containing a polymerizable liquid crystal compound” were used for the production of the retardation plate.

(1) Comparative Example 1
[Preparation 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 resulting mixture was stirred at 80 ° C. for 1 hour to obtain a composition for forming a photo-alignment film.

重合開始剤：２−ジメチルアミノ−２−ベンジル−１−（４−モルホリノフェニル）ブタン−１−オン（イルガキュア３６９；チバ スペシャルティケミカルズ社製）
レベリング剤：ポリアクリレート化合物（ＢＹＫ−３６１Ｎ；ＢＹＫ−Ｃｈｅｍｉｅ社製） [Preparation of Composition A Containing Polymerizable Liquid Crystal Compound]
The following polymerizable liquid crystal compound A (12.0 parts), a leveling agent (0.12 parts, BYK-361N; manufactured by BYK-Chemie), the following polymerization initiator (0.72 parts), and cyclopentanone ( 100 parts of a solvent) was mixed to obtain a composition A containing a polymerizable liquid crystal compound A. The polymerizable liquid crystal compound A was synthesized by the method described in JP 2010-31223 A. When measured using an ultraviolet-visible spectrophotometer (UV3150, manufactured by Shimadzu Corporation), the maximum absorption wavelength λmax (LC) of the polymerizable liquid crystal compound A was 350 nm.
Polymerizable liquid crystal compound A:

Polymerization initiator: 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals)
Leveling agent: polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)

[Method for producing retardation plate]
A cycloolefin polymer film (COP; ZF-14; manufactured by Nippon Zeon Co., Ltd.) was used with a corona treatment device (AGF-B10; manufactured by Kasuga Denki Co., Ltd.) under the conditions of an output of 0.3 kW and a processing speed of 3 m / min. Processed once. The composition for forming a photo-alignment film is applied to the corona-treated surface with a bar coater, dried at 80 ° C. for 1 minute, and a polarized UV irradiation device (SPOT CURE SP-7 with a polarizer unit; manufactured by USHIO INC.) ) Was used to carry out polarized UV exposure with an integrated light amount of 100 mJ / cm ² to form an alignment film. It was 100 nm when the thickness of the obtained alignment film was measured with the ellipsometer M-220 (made by JASCO Corporation).

Subsequently, the composition A containing the polymerizable liquid crystal compound prepared above is applied onto the alignment film at a speed of 50 mm / sec with the wire of the bar coater set to # 30, and dried at 120 ° C. for 1 minute. did. Then, using a high-pressure mercury lamp (Unicure VB-15201BY-A; manufactured by Ushio Electric Co., Ltd.), ultraviolet light is irradiated from the side coated with the composition A (integrated light quantity at a wavelength of 313 nm in a nitrogen atmosphere: 500 mJ / cm ^2). The retardation plate A including the optically anisotropic layer 1 (retardation film) was formed. It was 2.28 micrometers when the thickness of the optically anisotropic layer 1 contained in the obtained phase difference plate A was measured with the laser microscope (LEXT; Olympus Corporation make).

[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 (optically anisotropic layer 1), a sheet-like sensation is formed on the optically anisotropic layer 1 side of the retardation plate A separately produced in the same manner. A pressure-sensitive adhesive (acrylic pressure-sensitive adhesive, colorless and transparent, non-oriented) manufactured by Lintec Co., Ltd. is bonded, and a glass plate is used on the pressure-sensitive adhesive side (in-plane retardation is 0 (zero) at 450 nm, 550 nm, and 650 nm). Then, the sample for measurement was prepared by transferring the optically anisotropic layer 1 to the glass plate by peeling off the cycloolefin polymer film. Using this sample, the in-plane retardation value Re (λ) at a wavelength of 450 nm, a wavelength of 550 nm, and a wavelength of 650 nm was measured with a birefringence measurement apparatus (KOBRA-WR; manufactured by Oji Scientific Instruments). The results are shown in Table 2.

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

[Polarizing plate I: Production of iodine PVA polarizing plate]
A 30 μm-thick polyvinyl alcohol film (average polymerization degree of about 2400, saponification degree of 99.9 mol% or more) was uniaxially stretched about 5 times by dry stretching, and further kept at 40 ° C. pure water while maintaining the tension state. For 40 seconds. Then, the dyeing | staining process was performed by being immersed for 30 second at 28 degreeC in the dyeing | staining aqueous solution whose mass ratio of iodine / potassium iodide / water is 0.044 / 5.7 / 100.
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. Subsequently, after washing with pure water at 8 ° C. for 15 seconds, the film is dried at 60 ° C. for 50 seconds and then at 75 ° C. for 20 seconds while being held at a tension of 300 N, and iodine is adsorbed and oriented on the polyvinyl alcohol film. A polarizer having a thickness of 12 μm was obtained.

  A water-based adhesive was injected between the obtained polarizer and a triacetyl cellulose film (TAC, KC4UY, manufactured by Konica Minolta Co., Ltd.), and bonded with a nip roll. While maintaining the tension of the obtained bonded product at 430 N / m, it was dried at 60 ° C. for 2 minutes to obtain a polarizing plate I having a cycloolefin film as a protective film on one side. The water-based adhesive is composed of 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318; manufactured by Kuraray Co., Ltd.), water-soluble polyamide epoxy resin (Smiles Resin 650; manufactured by Sumika Chemtex Co., Ltd.) 1.5 parts of an aqueous solution having a solid concentration of 30%) was added.

The light absorption characteristics of the obtained polarizing plate I were measured as follows.
Using a spectrophotometer (V-7100; manufactured by JASCO Corporation) with a folder with a polarizer, the absorbance in the transmission direction and the absorption direction of the obtained polarizing plate I was determined by a double beam method at a step of 380 to 2 nm. Measurement was performed in the wavelength range of 680 nm. Table 1 shows the respective absorbances at 450 nm, 550 nm, and 650 nm. The absorbance at each wavelength that affects the reflected hue is A2 (450) = 4.7, A2 (550) = 4.9, and A2 (650) = 5.0, respectively, in a very neutral hue. there were.

  The pressure sensitive adhesive (Lintec) was prepared 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 °. An elliptical polarizing plate 1 was prepared by bonding using an acrylic pressure-sensitive pressure-sensitive adhesive, colorless and transparent, non-oriented). The elliptical polarizing plate was further bonded to an aluminum reflective base material (manufacturer: light, product number: HA0323) via a pressure sensitive adhesive. From this polarizing plate side, the light from the C light source was irradiated from the direction of 6 °, and the reflection spectrum was measured. The reflection chromaticity a * in the L * a * b * (CIE) color system was calculated from the obtained reflection spectrum and the color matching function of the C light source. The results are shown in Table 2. It represents that redness is so strong that the value of reflective chromaticity a * is large. Further, Table 2 shows calculated values of P (λ), P (450) / P (650), and 1-P (450).

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

(3) Example 2
A retardation plate comprising an optically anisotropic layer having a thickness of 2.50 μm by the same method as in Comparative Example 1 except that the amount of the solvent at the time of preparing the composition A containing the polymerizable liquid crystal compound was 91 parts by mass. (Type A) was prepared. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 3. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(4) Comparative Example 2
A retardation plate comprising an optically anisotropic layer having a thickness of 2.17 μm by the same method as in Comparative Example 1 except that the amount of the solvent during preparation of the composition A containing a polymerizable liquid crystal compound was 107 parts by mass. (Type A) was prepared. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 4. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(5) Example 3
In the composition A containing the polymerizable liquid crystal compound of Comparative Example 1, 10.5 parts by mass of the polymerizable liquid crystal compound A, 1.5 parts by mass of the following polymerizable liquid crystal compound B, and 120 parts by mass of the solvent were polymerizable. An optically anisotropic layer having a thickness of 1.93 μm was prepared in the same manner as in Comparative Example 1 except that composition B containing a liquid crystal compound was prepared and the wire thickness of the wire bar at the time of application was changed to # 30. A retardation plate B containing The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 5. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

なお、重合性液晶化合物ＢはパリオカラーＬＣ２４２（ＢＡＳＦ社製）を用いた。 Polymerizable liquid crystal compound B

As the polymerizable liquid crystal compound B, Paliocolor LC242 (manufactured by BASF) was used.

(6) Example 4
The thickness of the composition B containing the polymerizable liquid crystal compound was 115 parts by mass, and the thickness of the wire bar was set to # 30 by the same method as in Example 3 except that the wire thickness of the wire bar was set to # 30. Produced a retardation plate (type B) containing an optically anisotropic layer having a thickness of 2.01 μm. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 6. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(7) Example 5
According to the same method as in Example 3, except that the amount of the solvent at the time of preparation of the composition B containing the polymerizable liquid crystal compound was 108 parts by mass, and the wire thickness of the wire bar at the time of application was set to # 30. Produced a retardation plate (type B) comprising an optically anisotropic layer having a thickness of 2.14 μm. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 7. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(8) Comparative Example 3
According to the same method as in Example 3, except that the amount of the solvent at the time of preparation of the composition B containing the polymerizable liquid crystal compound was 127 parts by mass, and the wire thickness of the wire bar at the time of application was set to # 30. A retardation plate (type B) including an optically anisotropic layer having a thickness of 1.86 μm was prepared. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 8. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(9) Example 6
In composition A containing the polymerizable liquid crystal compound of Comparative Example 1, 9.5 parts by mass of polymerizable liquid crystal compound A, 2.5 parts by mass of polymerizable liquid crystal compound B, and 105 parts by mass of solvent were used. An optically anisotropic layer having a thickness of 1.72 μm was prepared in the same manner as in Comparative Example 1 except that the composition C containing the compound was prepared and the wire thickness of the wire bar at the time of application was # 20. Including retardation plate C was prepared. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 9. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(10) Example 7
According to the same method as in Example 6, except that the amount of the solvent at the time of preparing the composition C containing the polymerizable liquid crystal compound was 100 parts by mass, and the wire thickness of the wire bar at the time of application was set to # 20. Produced a retardation plate (type C) comprising an optically anisotropic layer having a thickness of 1.76 μm. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 10. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(11) Comparative Example 4
The thickness of the composition C containing the polymerizable liquid crystal compound was 110 parts by mass, and the thickness of the wire bar was set to # 20 by the same method as in Example 6 except that the thickness of the wire bar was set to # 20. A retardation plate (type C) containing an optically anisotropic layer having a thickness of 1.61 μm was prepared. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 11. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(12) Example 8
As the polarizing plate, a polarizing plate II prepared by the following method: a host guest polarizing plate was used.
[Preparation of Composition A for Forming Polarizing Film]
Polymeric liquid crystal compounds C and D shown below, dichroic dyes A to C, a polymerization initiator, a leveling agent, and a solvent are mixed and stirred at 80 ° C. for 1 hour to obtain a polarizing film forming composition A. Obtained. A film obtained by spin-coating the polarizing film-forming composition A and then drying the solvent was subjected to texture observation with a polarizing microscope while heating on a hot plate. It was confirmed to be a smectic liquid crystal exhibiting three liquid crystal phase states: (62 ° C.), smectic B phase (76 ° C.), smectic A phase (105 ° C.), nematic phase (114 ° C.), and liquid phase.

重合性液晶化合物Ｄ（１０部）：

二色性色素Ａ（３．０部）λＭＡＸ＝４００ｎｍ：

二色性色素Ｂ（３．０部）λＭＡＸ＝５２０ｎｍ：

二色性色素Ｃ（４．３部）λＭＡＸ＝６４０ｎｍ：

重合開始剤：２−ジメチルアミノ−２−ベンジル−１−（４−モルホリノフェニル）ブタン−１−オン（イルガキュア３６９；チバ スペシャルティケミカルズ社製）（２．４部）
レベリング剤：ポリアクリレート化合物（ＢＹＫ−３６１Ｎ；ＢＹＫ−Ｃｈｅｍｉｅ社製）（０．６部）
溶剤：トルエン（１００部） Polymerizable liquid crystal compound C (30 parts):

Polymerizable liquid crystal compound D (10 parts):

Dichroic dye A (3.0 parts) λMAX = 400 nm:

Dichroic dye B (3.0 parts) λMAX = 520 nm:

Dichroic dye C (4.3 parts) λMAX = 640 nm:

Polymerization initiator: 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals) (2.4 parts)
Leveling agent: polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) (0.6 parts)
Solvent: Toluene (100 parts)

[Method for producing host guest polarizing plate]
Triacetyl cellulose film (TAC; KC4UY; manufactured by Konica Minolta Co., Ltd.) is processed once using a corona treatment device (AGF-B10; manufactured by Kasuga Denki Co., Ltd.) under conditions of an output of 0.3 kW and a processing speed of 3 m / min. did. On the surface subjected to corona treatment, a composition for forming an alignment film photo-alignment film prepared by the same method as in Comparative Example 1 was applied with a bar coater, dried at 80 ° C. for 1 minute, and polarized UV irradiation device (polarizer unit) Using an attached SPOT CURE SP-7 (manufactured by Ushio Inc.), polarized UV exposure was performed with an integrated light amount of 100 mJ / cm ² to form an alignment film. It was 100 nm when the thickness of the obtained alignment film was measured with the ellipsometer M-220 (made by JASCO Corporation).

Subsequently, on the obtained alignment film, the polarizing film forming composition A prepared above was applied at a speed of 25 mm / sec with the bar coater wire set to # 10 and dried at 120 ° C. for 1 minute. did. Then, using a high-pressure mercury lamp (Unicure VB-15201BY-A; manufactured by Ushio Electric Co., Ltd.), ultraviolet light is irradiated from the side coated with the composition A (integrated light quantity at a wavelength of 313 nm in a nitrogen atmosphere: 500 mJ / cm ^2). ), A polarizing plate II containing a polymer obtained by polymerizing the polymerizable liquid crystal compound in a state where the polymerizable liquid crystal compound and the dichroic dye were aligned in the horizontal direction was formed. It was 2.10 micrometers when the thickness of the obtained polymer was measured with the laser microscope (LEXT; Olympus Corporation make).

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.
Absorbance at each wavelength affecting the reflected hue was A2 (450) = 1.8, A2 (550) = 2.0, A2 (650) = 3.2, and it was a bluish hue. .

  The polarizing plate II produced as described above and a retardation plate (type A, thickness of optically anisotropic layer 2.17 μm) prepared in the same manner as in Comparative Example 2, the absorption axis of the polarizing plate II, and this Bonding using a pressure sensitive adhesive (Acrylic pressure sensitive adhesive made by Lintec Co., Ltd.) so that the angle (θ) formed by the slow axis of the retardation plate is 45 °, and producing an elliptically polarizing plate 12 did. The elliptical polarizing plate was further bonded to an aluminum reflective base material (manufacturer: light, product number: HA0323) via a pressure sensitive adhesive. From this polarizing plate side, the light from the C light source was irradiated from the direction of 6 °, and the reflection spectrum was measured. The reflection chromaticity a * in the L * a * b * (CIE) color system was calculated from the obtained reflection spectrum and the color matching function of the C light source. The results are shown in Table 2. Further, the in-plane retardation values Re (λ) and P (λ) calculated by the same method as in Comparative Example 1, P (450) / P (650) and 1-P (450) The values are shown in Table 2.

(13) Example 9
A polarizing plate II produced by the same method as in Example 8 and a retardation plate produced by the same method as in Comparative Example 1 (type A, thickness of optically anisotropic layer 2.28 μm) are the same as in Example 8. The elliptically polarizing plate 13 was prepared by stacking according to the above procedure. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were measured by the same method as in Example 8. Table 2 shows the results of calculating the calculated value of P (λ), and the values of P (450) / P (650) and 1-P (450).

(14) Example 10
A polarizing plate II produced by the same method as in Example 8 and a retardation plate (type A, thickness of optically anisotropic layer 2.42 μm) produced by the same method as in Example 1 were the same as in Example 8. Thus, an elliptically polarizing plate 14 was produced. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were measured by the same method as in Example 8. Table 2 shows the results of calculating the calculated value of P (λ), and the values of P (450) / P (650) and 1-P (450).

(15) Example 11
A polarizing plate II produced by the same method as in Example 8 and a retardation plate (type B, thickness of optically anisotropic layer 1.86 μm) produced by the same method as in Comparative Example 3 are the same as in Example 8. Thus, the elliptically polarizing plate 15 was produced. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were measured by the same method as in Example 8. Table 2 shows the results of calculating the calculated value of P (λ), and the values of P (450) / P (650) and 1-P (450).

(16) Example 12
A polarizing plate II produced by the same method as in Example 8 and a retardation plate produced by the same method as in Example 3 (type B, thickness of optically anisotropic layer 1.93 μm) are the same as in Example 8. Thus, the elliptically polarizing plate 16 was produced. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were measured by the same method as in Example 8. Table 2 shows the results of calculating the calculated value of P (λ), and the values of P (450) / P (650) and 1-P (450).

(17) Example 13
A polarizing plate II produced by the same method as in Example 8 and a retardation plate produced by the same method as in Example 4 (type B, thickness of optically anisotropic layer 2.01 μm) are the same as in Example 8. Thus, the elliptically polarizing plate 17 was produced. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were measured by the same method as in Example 8. Table 2 shows the results of calculating the calculated value of P (λ), and the values of P (450) / P (650) and 1-P (450).

(18) Example 14
A polarizing plate II produced by the same method as in Example 8 and a retardation plate (type C, thickness of optically anisotropic layer 1.61 μm) produced by the same method as in Comparative Example 4 were the same as in Example 8. Thus, an elliptically polarizing plate 18 was produced. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were measured by the same method as in Example 8. Table 2 shows the results of calculating the calculated value of P (λ), and the values of P (450) / P (650) and 1-P (450).

(19) Example 15
A polarizing plate II produced by the same method as in Example 8 and a retardation plate (type C, thickness of optically anisotropic layer 1.72 μm) produced by the same method as in Example 6 were the same as in Example 8. Thus, an elliptically polarizing plate 19 was produced. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were measured by the same method as in Example 8. Table 2 shows the results of calculating the calculated value of P (λ), and the values of P (450) / P (650) and 1-P (450).

(20) Example 16
A polarizing plate II produced by the same method as in Example 8 and a retardation plate (type C, thickness of optically anisotropic layer 1.76 μm) produced by the same method as in Example 7 were the same as in Example 8. Thus, the elliptically polarizing plate 20 was produced. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were measured by the same method as in Example 8. Table 2 shows the results of calculating the calculated value of P (λ), and the values of P (450) / P (650) and 1-P (450).

(21) Comparative Example 5
In composition A containing the polymerizable liquid crystal compound of Comparative Example 1, the polymerizable liquid crystal compound A was not blended, the polymerizable liquid crystal compound B was 12.0 parts by mass, and the amount of the solvent was 100 parts by mass. In the same manner as in Comparative Example 1 except that the composition D was prepared and the wire thickness of the wire bar at the time of application was set to # 7, the optical anisotropic layer having a thickness of 0.93 μm was included. A phase difference plate D was produced. This retardation plate did not satisfy the above formula (3) and did not have reverse wavelength dispersion. The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 21. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(22) Comparative Example 6
According to the same method as in Comparative Example 5, except that the amount of the solvent at the time of preparing the composition D containing the polymerizable liquid crystal compound was 100 parts by mass, and the wire thickness of the wire bar at the time of application was set to # 9. Produced a retardation plate (type D, thickness of optically anisotropic layer 0.99 μm). The obtained retardation plate and the polarizing plate I produced by the same method as in Comparative Example 1 were laminated by the same procedure as in Comparative Example 1 to produce an elliptical polarizing plate 22. The in-plane retardation value Re (λ) and reflection chromaticity a * of the obtained retardation plate of the elliptically polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

  The polarizing plate I was a polarizing plate having a very neutral hue, and the polarizing plate II was a polarizing plate having a bluish hue.

  In the elliptically polarizing plates of Examples 1 to 16 that satisfy all the optical characteristics represented by the following formulas (1) to (4), the value of the reflection chromaticity a * is small (a value close to 0), and the reflection color is It was confirmed that the elliptically polarizing plate was very neutral and improved in redness. On the other hand, in the elliptically polarizing plates of Comparative Examples 1 to 4 having no optical characteristics represented by the following formula (1), the reflection chromaticity a * was large and the reflection color was reddish. . Further, in the elliptical polarizing plates of Comparative Examples 5 and 6 that do not satisfy the optical characteristics represented by the formula (3) and do not have reverse wavelength dispersion, the value of the reflection chromaticity a * is very large, and the redness of the reflection color Was a very strong elliptically polarizing plate.

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)

P (λ) can be arbitrarily adjusted by controlling the absorption selection characteristics of the polarizing plate, the wavelength dispersion of the retardation plate, and the film thickness. Specifically, for example, in the case of an iodine PVA polarizing plate, the absorption selection characteristic of the polarizing plate can be controlled by the temperature at the time of dyeing, the I ₂ concentration / KI concentration, the drying conditions, and the like. Then, the absorption characteristic of red light is improved as compared with blue light. Further, when the drying temperature is increased, the blue light absorption characteristic is improved as compared with the red light. In the case of a liquid crystal host-guest polarizing plate, the absorption selection characteristic can be controlled by controlling the addition amount and ratio of the dichroic dye that is a guest molecule. For example, when mixing a plurality of dyes, only the red light absorption property can be selectively improved by blending more blue dyes than other dyes. The wavelength dispersion of the retardation plate can be controlled, for example, by mixing a liquid crystal compound exhibiting reverse wavelength dispersion and a liquid crystal compound exhibiting positive dispersion at an arbitrary ratio. Further, the retardation value decreases as the thickness of the retardation plate decreases. So long as capable of controlling film thickness, it is possible to control the retardation value more convenient to control the film thickness, for example, a liquid crystal compound having a positive wavelength dispersion to be a desired wavelength dispersion By mixing the liquid crystal compound exhibiting the reverse wavelength dispersion and adjusting the film thickness of the retardation plate, the value of P (λ) can be easily controlled to a desired value.

Claims (10)

An elliptically polarizing plate including a polarizing plate and a retardation plate and satisfying all 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)
[In the above formulas (1) to (4),
P (λ) = tan {sin ⁻¹ ((I1 (λ) × sinΠ (λ) × sin2θ−I2 (λ) × sinΠ (λ) × cos2θ) / I2 (λ)) / 2},
I1 (λ) = (10− ^{A1 (λ)} −10− ^{A2 (λ)} ) / 2, I2 (λ) = (10− ^{A1 (λ)} + 10− ^{A2 (λ)} ) / 2, and Π (Λ) = Re (λ) / λ × 2π, A1 (λ) represents the absorbance in the transmission axis direction of the polarizing plate at the wavelength λ, and A2 (λ) represents the absorbance in the absorption axis direction of the polarizing plate at the wavelength λ. Re (λ) represents the front 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. ] The elliptically polarizing plate according to claim 1, wherein the front retardation at a wavelength of 550 nm of the retardation plate satisfies the following formula (5).
130 nm ≦ Re (550) ≦ 150 nm (5)
[In the formula, Re (550) represents frontal retardation at a wavelength of 550 nm. ] The elliptically polarizing plate according to claim 1 or 2, wherein the absorbance (A2) in the absorption axis direction at a wavelength λ of the polarizing plate satisfies all of the following formulas (6) to (8).
1 ≦ A2 (450) ≦ 6 (6)
1 ≦ A2 (550) ≦ 6 (7)
2 ≦ A2 (650) ≦ 6 (8) The elliptically polarizing plate according to any one of claims 1 to 3, wherein the transmission axis direction absorbance (A1) at a wavelength λ of the polarizing plate satisfies all of 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) The elliptically polarizing plate according to any one of claims 1 to 4, wherein the absorbance (A2) in the absorption axis direction at a wavelength λ of the polarizing plate satisfies the following formulas (12) and (13).
A2 (650)> A2 (450) (12)
A2 (650)> A2 (550) (13)   The elliptically polarizing plate according to any one of claims 1 to 5, wherein an angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate is substantially 45 °.   The elliptically polarizing plate according to any one of claims 1 to 6, wherein the retardation plate is a layer made of a polymer in an alignment state of the polymerizable liquid crystal compound.   The elliptically polarizing plate in any one of Claims 1-7 in which the polarizing plate contains the polymer of this polymeric liquid crystal compound in the orientation state of the mixture containing a polymeric liquid crystal compound and a dichroic dye.   A liquid crystal display device comprising the elliptically polarizing plate according to claim 1.   The organic electroluminescence display containing the elliptically polarizing plate in any one of Claims 1-8.