JP6876638B2 - Elliptical polarizing plate - Google Patents

Description

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

Circular polarizing plates are widely used in flat panel display devices (FPDs) such as organic EL display devices for the purpose of preventing reflection from external light. The circular polarizing plate has a configuration in which a linear polarizing plate and a retardation plate (λ / 4 plate) are laminated, but when a general positive wavelength dispersible material is applied as the retardation plate, λ over the entire visible light range. Since the phase difference of / 4 cannot be expressed, there is a problem that the reflection color is colored. In order to solve this problem, Patent Document 1 uses a reverse wavelength dispersible liquid crystal material designed to reduce birefringence at short wavelengths, and Patent Document 2 uses a reverse wavelength dispersive polymer film material. A circularly polarizing plate used as a retardation plate is disclosed.

Japanese Patent No. 3325560 Japanese Unexamined Patent Publication No. 2014-123134

Theoretically, by designing the retardation plate so that the retardation is 1/4 at the wavelength of the entire visible light range (with inverse wavelength dispersibility), it is possible to obtain a circularly polarizing plate having no reflected color.
That is, as theoretical values, the polarizing Re (450) at approximately blue light 450 nm is 450/4 = 112.5 nm, the retardation Re (550) at approximately green light 550 nm is 550/4 = 137.5 nm, and the retardation Re at approximately 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, although the retardation plate as disclosed in Patent Documents 1 and 2 can approach the theoretical value for short wavelength light, it cannot be the theoretical value for long wavelength light. is there. This is because the inverse wavelength dispersive birefringence as a substantial retardation plate is obtained by subtracting the birefringence at each wavelength of the positively oriented birefringence structure and the negatively oriented birefringence structure, which is unique to the material. This is because the wavelength dispersibility of is not a linear change. In short, it is due to the fundamental principle that the shorter the wavelength, the larger the dispersion, and the longer the wavelength, the smaller the dispersion. As a result, when the retardation plate is designed so that the green light that maximizes the human visual sensitivity becomes the theoretical value, the reflection prevention of the red light becomes insufficient, and the reflected color may become red. ..

Therefore, an object of the present invention is to provide an elliptical polarizing plate capable of suppressing coloring of reflected colors at wavelengths in the entire visible light range and imparting good display characteristics when used in a display device.

The present invention provides the following preferred embodiments [1] to [10].
[1] An elliptical polarizing plate that includes a polarizing plate and a retardation plate and satisfies 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)) is / 2, I2 (λ) = (10 -A1 (λ) +10 -A2 (λ)) is / 2, [pi (Λ) = Re (λ) / λ × 2π, A1 (λ) represents the transmissive axial absorbance of the polarizing plate at the wavelength λ, and A2 (λ) represents the absorption axial absorbance 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 elliptical polarizing plate according to the above [1], wherein the frontal retardation of the retardation plate at a wavelength of 550 nm satisfies the following formula (5).
130nm ≤ Re (550) ≤ 150nm (5)
[In the formula, Re (550) represents front retardation at a wavelength of 550 nm. ]
[3] The elliptical polarizing plate according to the above [1] or [2], wherein the absorption axial absorbance (A2) 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 elliptical polarizing plate according to any one of the above [1] to [3], wherein the absorbance (A1) in the transmission axis direction 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 elliptical polarizing plate according to any one of [1] to [4] above, wherein the absorbance (A2) in the absorption axis direction 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 elliptical polarizing plate according to any one of [1] to [5] above, wherein the angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate is substantially 45 °.
[7] The elliptical polarizing plate according to any one of [1] to [6] above, wherein the retardation plate is a layer made of a polymer in an oriented state of a polymerizable liquid crystal compound.
[8] The elliptically polarized light according to any one of [1] to [7] above, wherein the polarizing plate contains a polymer of the polymerizable liquid crystal compound in an orientation state of a mixture containing the polymerizable liquid crystal compound and a dichroic dye. Board.
[9] A liquid crystal display device including the elliptical polarizing plate according to any one of the above [1] to [8].
[10] An organic EL display device including the elliptical polarizing plate according to any one of the above [1] to [8].

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

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described here, and various modifications can be made without impairing the gist 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 elliptical polarizing plate of the present invention includes a polarizing plate and a retardation plate. The elliptical 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 above equations (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 transmissive axial absorbance of the polarizing plate at the wavelength λ, A2 (λ) represents the absorption axial absorbance of the polarizing plate at the wavelength λ, and Re (λ) represents the front retardation at the wavelength λ. Represented, θ represents the 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), such an elliptical polarizing plate can suppress red light loss, which has been a problem of the conventional inverse wavelength dispersive phase difference, and when used in a display device. It is an elliptical polarizing plate that can impart good display characteristics to the light.

In the above equations (1) and (2), P (λ) represents an elliptically polarized state at a wavelength of λ nm, P (450) is an elliptically polarized state for light having a wavelength of 450 nm, and P (550) is an ellipse for light having a wavelength of 550 nm. The polarized state, P (650), represents an elliptically polarized state for light having a wavelength of 650 nm. Here, A1 (λ) is the transmission axial absorbance of the polarizing plate at the wavelength λ, A2 (λ) is the absorption axial absorbance of the polarizing plate at the wavelength λ, and Π (λ) is the absorption axial absorbance at the wavelength λ. It is the phase difference (non-dimensional value) of the retardation 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 circle the state of circularly polarized light.

The values of P (450) / P (650) represented by the formula (1) represent the circularly polarized light states at wavelengths of 450 nm and 650 nm, respectively, and the closer to 1 the elliptical polarizing plate with less reflected color is used. It is possible to achieve a display with good color when used in a display device. When the value of the formula (1) is less than 0.8, the reflected color tends to be bluish green. When the value of the formula (1) exceeds 1.2, the reflected color tends to be red. In the elliptical polarizing plate of the present invention, the value of P (450) / P (650) depends on the display device, but is, for example, preferably 0.85 or more, more preferably 0.9 or more, and preferably 1. It is 15 or less, more preferably 1.1 or less.

If the value of P (λ) is small, the circularly polarized light conversion becomes insufficient, and the antireflection characteristics on the display device deteriorate. In particular, when the value of P (550) at the wavelength of 550 nm, which has the highest luminosity factor, is small, it becomes difficult to sufficiently suppress light loss due to reflection. Therefore, the elliptical polarizing plate of the present invention is represented by the above formula (2). It is necessary to satisfy the optical characteristics to be satisfied. When the value of P (550) is less than 0.7, the viewer can easily recognize the light omission. Therefore, in the present invention, the value of P (550) is preferably 0.75 or more, 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.
Further, the value of P (λ) of the elliptical polarizing plate of the present invention is preferably 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 wavelength on the short wavelength side of visible light and P (650) at the wavelength on the long wavelength side of visible light are both 0.7 or more.

The elliptical polarizing plate of the present invention satisfies the above formula (3) showing anti-wavelength dispersibility. The inverse wavelength dispersibility is an optical characteristic in which the in-plane retardation value at a short wavelength becomes larger than the in-plane retardation value at a long wavelength. In the elliptical polarizing plate of the present invention, it is preferable that Re (450) / Re (550) ≦ 1 is satisfied, and 0.82 ≦ Re (450) / Re (550) ≦ 0.93 is more preferable.

Further, the elliptical polarizing plate of the present invention needs to satisfy the optical characteristics represented by the above formula (4) from the viewpoint of optical design of the inverse wavelength dispersion characteristic. The formula (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 the theoretical value 1 representing the circularly polarized state within a predetermined range. By doing so, the antireflection performance of blue light can be lowered. In particular, by satisfying the optical characteristics of the formula (4) and setting the value of P (450) / P (650) in the formula (1) to 0.8 to 1.2, the color tone is good. The display is achieved. In the elliptical polarizing plate of the present invention, the value of 1-P (450) depends on the display device, but is, for example, preferably 0.08 or more, more preferably 0.1 or more, and preferably 0.26 or less. More preferably, it is 0.24 or less.

P (λ) can be arbitrarily adjusted by controlling the absorption selectivity of the polarizing plate, the wavelength dispersibility of the retardation plate, and the film thickness. Specifically, for example, in the case of an iodine PVA polarizing plate, the absorption selectivity of the polarizing plate _{can be controlled by the temperature at the time of staining, the I 2} concentration / KI concentration, the drying conditions, etc., and the KI concentration is increased. Then, the absorption characteristics of red light are improved as compared with blue light. Further, when the drying temperature is raised, the absorption characteristics of blue light are improved as compared with red light. Further, in the case of the liquid crystal host guest type polarizing plate, it is possible to control the absorption selection characteristics by controlling the addition amount and ratio of the dichroic dye which is a guest molecule. For example, when a plurality of dyes are mixed, by blending more blue dyes than other dyes, only the absorption characteristics of red light can be selectively improved. The wavelength dispersibility of the retardation plate can be controlled, for example, by mixing a liquid crystal compound exhibiting reverse wavelength dispersibility and a liquid crystal compound exhibiting positive dispersibility in an arbitrary ratio. Further, the retardation value decreases as the film thickness of the retardation plate becomes thinner. As long as the film thickness is within a controllable range, the phase difference value can be easily controlled by controlling the film thickness. For example, with a liquid crystal compound exhibiting positive wavelength dispersibility so as to obtain a desired wavelength dispersibility. The value of P (λ) can be easily controlled to a desired value by adjusting the film thickness of the retardation plate after mixing the liquid crystal compound exhibiting the inverse wavelength dispersibility.

In the present invention, the antireflection characteristics of the elliptical polarizing plate satisfying the above equations (1) to (4) are, for example, (i) a phase difference that makes the front retardation value of the retardation plate larger than the theoretical value. The absorbency of the (iii) polarizing plate at a wavelength of around 650 nm (red light), which separates the wavelength dispersibility of the plate from the theoretical value, is set at other wavelengths such as a wavelength of around 450 nm (blue light) and a wavelength of around 550 nm (green light). It can be controlled by making it larger than the absorbency in the region. Regarding (i), for example, since the front retardation value is a value determined by Δn (λ) × d (Δn: refractive index difference, d: thickness of the retardation plate), 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 form the elliptical polarizing plate of the present invention is polymerizable because it exhibits optical anisotropy by coating and orienting a polymerizable liquid crystal compound from the viewpoint of thinning and easy control of wavelength dispersibility. It is preferably a layer made of a polymer in the oriented state of the liquid crystal compound (hereinafter, also referred to as an “optically anisotropic layer”). 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 the polymerization reaction by active radicals, acids, etc. generated from the photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group, an oxetanyl group and the like. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The liquid crystal property may be a thermotropic liquid crystal or a riotropic liquid crystal, but the thermotropic liquid crystal is preferable in that precise film thickness control is possible. Further, the phase-ordered structure of the thermotropic liquid crystal may be either a nematic liquid crystal or a smectic liquid crystal.

In the present invention, as the polymerizable liquid crystal compound, the structure of the following formula (I) is particularly preferable from the viewpoint of exhibiting the above-mentioned inverse wavelength dispersibility.

In the formula (I), Ar represents a divalent aromatic group, and the divalent aromatic group contains at least one or more of a nitrogen atom, an oxygen atom, and a sulfur atom.
G ¹ and G ² independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, respectively. Here, the hydrogen atom contained in the divalent aromatic group or the 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, and carbon. The carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an alkoxy group, a cyano group or a nitro group of the number 1 to 4, which is 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 independently single-bonded or divalent linking groups, respectively.
k and l each independently represent an integer of 0 to 3, and satisfy the relationship of 1 ≦ k + l. Here, when 2 ≦ k + l, 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 represent an alkanediyl group having 1 to 17 carbon atoms, wherein the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and the alkanediyl group may be substituted with the halogen atom. The included −CH ₂₋ may be substituted with −O−, −Si−.
P ¹ and P ² 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 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, preferably a 1,4-phenyl group. It is a 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, and more preferably 1,4 substituted with a methyl group. -Phenyl group, unsubstituted 1,4-phenyl group, or unsubstituted 1,4-trans-cyclohexyl group, particularly preferably unsubstituted 1,4-phenyl group, or unsubstituted 1,4- It is a trans-cyclohexyl group.
Further, at least one of a plurality of G ¹ and G ² present is preferably a divalent alicyclic hydrocarbon group, and at least one of ^{G 1} and G ^{2 bonded to L 1} or L ² is present. More preferably, it is a divalent alicyclic hydrocarbon group.

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

B ¹ and B ² are independent, preferably single bond, -O-, -S-, -CH ₂ O-, -COO-, or -OCO-, and more preferably single bond, -O. -, -COO-, or -OCO-.

From the viewpoint of expressing reverse wavelength dispersibility, k and l are preferably in the range of 2 ≦ k + l ≦ 6, preferably k + l = 4, and more preferably k = 2 and l = 2. When k = 2 and l = 2, a symmetrical structure is obtained, which is preferable.

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.

The ^{polymerizable group represented by P 1} or P ² includes an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, and an oxylanyl group. , And an oxetanyl group and the like.
Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an 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. .. Among them, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is more preferable to have a benzothiazole group. When Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

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

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

In formulas (Ar-1) to (Ar-20), * marks represent connecting parts, and Z ⁰ , Z ¹ and Z ² are independently hydrogen atoms, halogen atoms, and 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, Alkylthio group with 1 to 12 carbon atoms, N-alkylamino group with 1 to 12 carbon atoms, N, N-dialkylamino group with 2 to 12 carbon atoms, N-alkylsulfamoyl group with 1 to 12 carbon atoms or carbon Represents an N, N-dialkylsulfamoyl group of number 2-12.

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

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

W ¹ and W ² 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 in 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, and a phenyl group. , A naphthyl group is preferable, and a phenyl group is more preferable. The aromatic heterocyclic group has 4 to 20 carbon atoms containing at least one heteroatom such as a nitrogen atom such as a frill group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group or a benzothiazolyl group, an oxygen atom and a sulfur atom. Aromatic heterocyclic groups are mentioned, and a frill group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group are preferable.

Y ¹ , Y ² and Y ³ may be independently substituted polycyclic aromatic hydrocarbon groups or polycyclic aromatic heterocyclic groups, respectively. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

Z ⁰ , Z ¹ and Z ² are preferably hydrogen atoms, halogen atoms, alkyl groups having 1 to 6 carbon atoms, cyano groups, nitro groups, and alkoxy groups having 1 to 12 carbon atoms, respectively. ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group, and Z ¹ and Z ² are further preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, and a cyano group.

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

Among the formulas (Ar-1) to (Ar-20), the formulas (Ar-6) and (Ar-7) are preferable 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 attached and Z ^0. For example, 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, a pyrrolidine ring and the like can be mentioned. This aromatic heterocyclic group may have a substituent. Further, Y ¹ may be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted as described above, together with the nitrogen atom to which ^{the Y 1 is bonded and Z 0.}

By orienting such a polymerizable liquid crystal compound to form a polymer in the oriented state of the polymerizable liquid crystal compound, a retardation plate having anti-wavelength dispersibility can be produced. At this time, 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, since the wavelength dispersibility can be easily controlled according to the polarizing plate constituting the elliptical polarizing plate and the display device incorporating the elliptical polarizing plate, two or more types of polymerizable liquid crystals having different wavelength dispersibility can be easily controlled. It is preferable to mix the compounds. In this case, it is preferable to include the polymerizable liquid crystal compound represented by the formula (I) as the polymerizable liquid crystal compound to be mixed.

In one embodiment of the present invention, the retardation plate constituting the elliptical polarizing plate of the present invention has a wavelength dispersibility 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. As another polymerizable liquid crystal compound different from the polymerizable liquid crystal compound represented by the formula (I), it has an inverse wavelength dispersibility having a molecular structure different from that of the polymerizable liquid crystal compound represented by the formula (I). It may be the polymerizable liquid crystal compound shown, or it may be the polymerizable liquid crystal compound showing positive wavelength dispersibility. In a preferred embodiment of the present invention, the retardation plate constituting the elliptical polarizing plate of the present invention is polymerizable, which exhibits positive wavelength dispersibility, in addition to the polymerizable liquid crystal compound represented by the formula (I). Contains liquid crystal compounds. This makes it possible to more easily control the wavelength dispersibility of the retardation plate.

In the present invention, when the liquid crystal compound constituting the retardation plate contains a polymerizable liquid crystal compound exhibiting positive wavelength dispersibility, its structure is not particularly limited, and the positive wavelength generally used in the art. 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 those in the structural formula (I). It is defined, and G ³ is independently ^{defined in the same way 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 dispersibility include "3.8.6 network (complete cross-linking)" in the Liquid Crystal Handbook (edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. on October 30, 2000). Type) ”,“ 6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material ”, among the compounds described, compounds having a polymerizable group can be mentioned. Moreover, you may use a commercially available product as these polymerizable 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, so that the elliptical polarizing plate is subjected to the above equation (1). It is possible to impart optical characteristics that satisfy ~ (4). Here, in the present invention, "separating the wavelength dispersibility of the retardation plate from the theoretical value" means that R (λ1) / R (λ2) ≈λ1 / λ2 (λ1 <λ2). The wavelength dispersibility of the retardation plate can be adjusted by the mixing ratio of the polymerizable liquid crystal compound having reverse wavelength dispersibility and the polymerizable liquid crystal compound having positive wavelength dispersibility, and the polymerizable liquid crystal compound having positive wavelength dispersibility. The higher the ratio of, the more R (λ1) / R (λ2)> λ1 / λ2 (λ1 <λ2). Here, R (λ1) represents the front retardation value at the wavelength λ1 and R (λ2) represents the front retardation value at the wavelength λ2. Further, the higher the ratio of the polymerizable liquid crystal compound having positive wavelength dispersibility, the larger the retardation value of the retardation plate. Therefore, in the present invention, for example, when two or more kinds of polymerizable liquid crystal compounds including the polymerizable liquid crystal compound represented by the formula (I) are mixed to form a retardation plate, the mixing ratio is the formula. 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, but it is represented by the formula (I) with respect to the total amount of the total polymerizable liquid crystal compounds constituting the retardation plate. The proportion of the polymerizable liquid crystal compound to be produced is preferably 50% by mass or more, more preferably 60% by mass or more.

In a particularly preferred embodiment of the elliptical polarizing plate of the present invention, the retardation plate constituting the elliptical 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 in a mixing ratio of 100: 0 to 50:50, more preferably 100: 0 to 75:25.

Further, in one embodiment of the present invention, the front retardation of the retardation plate at a wavelength of 550 nm is based on the following formula (5):
130nm ≤ Re (550) ≤ 150nm (5)
It is preferable to satisfy. When the front retardation of the retardation plate at a wavelength of 550 nm satisfies the above formula (5), it functions as a so-called 1/4 wave plate. In particular, it is preferable to combine a polarizing plate having good absorption selectivity and a retardation plate satisfying the above formula (5). With such a combination, a circularly polarizing plate having good antireflection characteristics can be obtained. When combining the polarizing plate and the retardation plate, it is preferable that the respective optical axes are substantially 45 °.

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

The content of the polymerizable liquid crystal compound in the composition for forming the optically anisotropic layer (the total amount when a plurality of types are contained) is the formation of the optically anisotropic layer from the viewpoint of increasing the orientation of the polymerizable liquid crystal compound. It 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 further preferably 85 to 5 to 9 parts by mass with respect to 100 parts by mass of the solid content of the composition for use. It is 95 parts by mass. The solid content referred to here refers to the total amount of the components excluding the solvent from the composition for forming an optically anisotropic layer.

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 composition for forming an optically anisotropic layer such as a polymerizable liquid crystal compound is preferable, and the constituent components of the composition for forming an optically anisotropic layer such as a polymerizable liquid crystal compound are 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, and 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 carbides such as pentane, hexane and heptane. Hydrogen solvents; non-chlorinated aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene; Two or more kinds of organic solvents may be used in combination. Of 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 mass, more preferably 100 to 5000 parts by mass, and further preferably 100 to 2000 parts by mass with respect to 100 parts by mass of the solid content of the composition for forming an optically anisotropic layer. Is. The solid content 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 that can initiate a polymerization reaction of a polymerizable liquid crystal or the like. As the polymerization initiator, a photopolymerization initiator that generates radicals 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 manufactured by Ciba Japan Co., Ltd.), Sequol (registered trademark) BZ, Sequol Z. , Sakeall BEE (all manufactured by Seiko Kagaku Co., Ltd.), Kayacure (registered trademark) BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), ADEKA PUTMER (registered trademark) SP -152, ADEKA PUTMER SP-170 (all manufactured by ADEKA Corporation), TAZ-A, TAZ-PP (all manufactured by Siebel Hegner Japan), TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.) and the like. Of these, the α-acetophenone compound is preferable, and the α-acetophenone compound includes 2-methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-1- (4-morpholino). Phenyl) -2-benzylbutane-1-one, 2-dimethylamino-1- (4-morpholinophenyl) -2- (4-methylphenylmethyl) butane-1-one and the like can be mentioned, more preferably 2-one. Examples thereof include methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutane-1-one. Examples of commercially available α-acetophenone compounds include Irgacure 369, 379EG, 907 (all manufactured by BASF Japan Ltd.) and Sequol BEE (manufactured by Seiko Kagaku Co., Ltd.).

The photopolymerization initiator can fully utilize the energy emitted from the light source and is excellent in productivity. Therefore, 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. , 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 butyl catechol; pyrogallols, 2,2,6,6-tetramethyl-1- Radical trapping agents 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 orientation of the polymerizable liquid crystal compound. Yes, preferably 0.5 to 10 parts by mass.

Examples of the photosensitizer include xanthones such as xanthones and thioxanthones; anthracenes having substituents such as anthracene and alkyl ethers; phenothiazines; rubrenes.
By using a photosensitizer, the photopolymerization initiator can be made highly sensitive. The content of the photosensitizer is usually 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.

Examples of the leveling agent include organically modified silicone oil-based, polyacrylate-based and perfluoroalkyl-based leveling agents. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all 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 of which are Momentive Performance Materials Japan LLC) , Florinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (all manufactured by Sumitomo 3M Co., Ltd.), Megafuck (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-483 (all manufactured by DIC Co., Ltd.), Ftop (trade name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.), Surflon (registered) Trademarks) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (all manufactured by AGC Seimi Chemical Co., Ltd.) , Product name E1830, E5844 (manufactured by Daikin Fine Chemical Laboratory Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all trade names: manufactured by BM Chemie), etc. Can be mentioned. Two or more leveling agents may be combined.

By using a leveling agent, a smoother optically anisotropic layer can be formed.
Further, in the process of manufacturing the retardation plate, the fluidity of the composition for forming an optically anisotropic layer can be controlled, and the crosslink density of the retardation plate can be adjusted. The content of the leveling agent is usually 0.1 to 30 parts by mass, preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.

<Application of composition for forming an optically anisotropic layer>
When producing a polymer in an oriented state of a polymerizable liquid crystal compound, a composition for forming an optically anisotropic layer is applied onto a base material or an alignment film formed on the base material. It is preferably a resin base material. The resin base material is usually a transparent resin base material. The transparent resin base material means a base material having translucency capable of transmitting light, particularly visible light, and the translucency means a transmittance of 80% or more for light having a wavelength of 380 nm to 780 nm. Refers to the characteristic of As the resin base material, a film-like one is usually used, and a long film roll is preferably used.

Examples of the resin constituting the base material include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid ester; polyacrylic acid ester; cellulose ester; polyethylene naphthalate; polycarbonate; polysulfone; Polyethersulfone; polyetherketone; polyphenylene sulfide; and polyphenylene oxide and the like can be mentioned. Of these, a substrate made of polyolefin such as polyethylene, polypropylene, or norbornene-based polymer is preferable.

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

An alignment film may be formed on the surface of the base material on which the composition for forming an optically anisotropic layer is applied. The alignment film has an orientation regulating force for orienting 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 also has heat resistance in heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound described later. The one is preferable. Examples of the alignment film include an alignment film containing an alignment polymer, a photo-alignment film, and a grub alignment film having an uneven pattern or a plurality of grooves on the surface.

Such an alignment film facilitates the orientation of the polymerizable liquid crystal compound. Further, various orientations such as horizontal orientation, vertical orientation, hybrid orientation, and inclined orientation can be controlled depending on the type of alignment film and rubbing conditions. The value of the front retardation can be controlled by horizontally aligning the rod-shaped liquid crystal compound or vertically orienting the disk-shaped 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 oriented polymer is contained, the oriented polymer includes, for example, polyamides and gelatins having an amide bond, polyimide having an imide bond and polyamic acid which is a hydrolyzate thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, and the like. Examples thereof include polyoxazol, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylic acid esters. Of these, polyvinyl alcohol is preferable. Two or more oriented polymers may be combined.

The alignment film containing the orientation polymer is usually obtained by applying an orientation polymer composition in which the orientation polymer is dissolved in a solvent to a substrate and removing the solvent to form a coating film, or based on the orientation 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 oriented polymer in the oriented polymer composition may be within the range in which the oriented polymer is completely dissolved in the solvent. The content of the oriented polymer with respect to the oriented polymer composition is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass.

Oriented polymer compositions are available on the market. Examples of commercially available oriented polymer compositions include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optomer (registered trademark, manufactured by JSR Corporation) and the like.

Examples of the method of applying the oriented polymer composition to the base material include the same method as the method of applying the composition for forming an optically anisotropic layer described later to the base material. 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 oriented polymer composition may be subjected to a rubbing treatment. By applying the rubbing treatment, it is possible to impart an orientation regulating force to the coating film.

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

The photoalignment film is usually formed by applying a composition for forming a photoalignment film containing a polymer or monomer having a photoreactive group and a solvent to a substrate, removing the solvent, and then irradiating with polarized light (preferably polarized UV). You can get it. The photoalignment film can arbitrarily control the direction of the orientation regulating force by selecting the polarization direction of the polarized light to be irradiated.

A photoreactive group is a group that produces an orientation ability when irradiated with light. Specific examples thereof include groups involved in photoreactions that are the origin of orientation ability such as molecular orientation-inducing reactions, isomerization reactions, photodimerization reactions, photocrosslinking reactions, and photodecomposition reactions 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 a nitrogen-nitrogen bond are used. 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 preferable.

Examples of the photoreactive group having a C = C bond include a vinyl group, a polyene group, a stilbene group, a stillbazole group, a stillvazolium group, a chalcone group and a cinnamoyl group. Examples of the photoreactive group having a C = N bond include a group having a structure such as an aromatic 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 substituents such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group and an alkyl halide group.

A group involved in a photodimerization reaction or a photocrosslinking reaction is preferable because it has excellent orientation. Among them, a photoreactive group involved in a photodimerization reaction is preferable, a photoalignment film having a relatively small amount of polarized light required for orientation and excellent thermal stability and temporal stability can be easily obtained. And chalcone groups are preferred. As the polymer having a photoreactive group, a polymer having a cinnamoyl group such that the terminal portion of the side chain of the polymer 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 photo-alignment film can be adjusted by the type of the polymer or monomer and the thickness of the target photo-alignment film, and is at least 0.2% by mass or more. It is preferable that the amount is in the range of 0.3 to 10% by mass. The composition for forming a photoalignment film may contain a polymer material such as polyvinyl alcohol or polyimide or a photosensitizer as long as the characteristics of the photoalignment film are not significantly impaired.

Examples of the method of applying the composition for forming a photoalignment film to the base material include the same method as the method of applying the composition for forming an optically anisotropic layer described later to the base material. Examples of the method for removing the solvent from the applied composition for forming a photoalignment 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 directly irradiating the composition for forming a photoalignment film coated on the substrate with the solvent removed, the polarized light is irradiated from the substrate side and the polarized light is used as the basis. It may be in the form of penetrating the material and irradiating it. Further, it is preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in the wavelength range in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) having a wavelength in the range of 250 nm to 400 nm is particularly preferable. Examples of the light source for irradiating the polarized light include a xenon lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, an ultraviolet light laser such as KrF and ArF, and the like. Of these, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp are preferable because they have a high emission intensity of ultraviolet rays having a wavelength of 313 nm. Polarized UV can be irradiated by irradiating the light from the light source through an appropriate polarizing layer. Examples of the polarizing layer include a polarizing filter, a polarizing prism such as Gran Thomson and Gran Taylor, and a wire grid type polarizing layer.

<Application of composition for forming an optically anisotropic layer>
The composition for forming an optically anisotropic layer is applied onto the base material or the alignment film. Examples of the method for applying the composition for forming an optically anisotropic layer onto a substrate include an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a CAP coating method, a slit coating method, and a die coating method. Further, a method of applying using a coater such as a dip coater, a bar coater, or a spin coater can also be mentioned. Among them, the CAP coating method, the inkjet method, the dip coating method, the slit coating method, the die coating method and the coating method using a bar coater are preferable because they can be continuously applied in the Roll to Roll format. When applied in the Roll to Roll format, a composition for forming a photoalignment film or the like is applied to a substrate to form an alignment film, and the composition for forming an optically anisotropic layer is continuously applied on the obtained alignment film. It can also be applied to.

<Drying of composition for forming an optically anisotropic layer>
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, vacuum drying, and a method combining these. Of these, natural drying or heat drying is preferable. The drying temperature is preferably in the range of 0 to 250 ° C, more preferably in the range of 50 to 220 ° C, and even 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 photoalignment film and the orientation polymer composition can be dried in the same manner.

<Polymerization of polymerizable liquid crystal compounds>
In the present invention, photopolymerization is preferable as a method for polymerizing a polymerizable liquid crystal compound. Photopolymerization is carried out by irradiating 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 with active energy rays. The active energy rays to be irradiated include the type of the polymerizable liquid crystal compound contained in the dry film (particularly, the type of the photopolymerizable functional group contained in the polymerizable liquid crystal compound), and the photopolymerization initiator when the photopolymerization initiator is contained. It is appropriately selected according to the type of the mixture and the amount thereof. Specific examples thereof include one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-ray, α-ray, β-ray, and γ-ray. Among them, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use a photopolymerization apparatus widely used in the art. It is preferable to select the type of the sex liquid crystal compound.

When the composition for forming an optically anisotropic layer contains a photopolymerization initiator, it is preferable to select the type of the photopolymerization initiator so that the composition 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 excima laser, and a wavelength range. Examples thereof include an LED light source that emits 380 to 440 nm, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

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, still more preferably 0.1 seconds. It is 10 seconds.
Within the above range, an optically anisotropic layer having more excellent transparency can be obtained.

In the present invention, the retardation value of the retardation plate can be controlled by adjusting the film thickness of the retardation plate. If the composition constituting the retardation plate is the same, the retardation value increases by increasing the film thickness. When the elliptical polarizing plate is composed of a combination of a polarizing plate having the same composition and a retardation plate having the same composition, the P in the above formula (1) of the elliptical polarizing plate is increased by increasing the thickness of the retardation plate. 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 according to the type of the polymerizable liquid crystal compound constituting the retardation plate and the like, but it is usually used. , 0.1 to 5 μm, more preferably 0.5 to 4 μm, and even more preferably 1 to 3 μm. The film thickness can be controlled, for example, by adjusting the amount of the solvent contained in the composition for forming an optically anisotropic layer and the thickness of the coating film composed of the composition for forming an optically anisotropic layer. The thickness of the coating film is, for example, changing the thickness of the wire of the wire bar at the time of application, adjusting the discharge amount with the die coater, or changing the depth or peripheral speed of the groove with the microgravure coater. Can be adjusted by.

The elliptical 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 the 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-based resin film (PVA) is coated on one side with a polymer film (protective film). Alternatively, a polarizing plate having both sides protected may be mentioned. At this time, for example, a transparent resin film is used as the protective film, and the transparent resin is an acetyl cellulose resin typified by triacetyl cellulose or diacetyl cellulose, a methacrylic resin typified by polymethyl methacrylate, or polyester. Examples thereof include resins, polyolefin resins, polycarbonate resins, polyether ether ketone resins, and polysulfone resins. Further, a liquid crystal host guest type polarizing plate can also be used. As the liquid crystal host-guest type polarizing plate, for example, those exemplified in JP2012-58381, JP2013-37115, International Publication No. 2012/147633, and International Publication No. 2014/09921 can be used. The thickness of the polarizer is not particularly limited, but one usually having a thickness of 0.5 to 35 μm is used.

The polarizing plate is a film to which polarization absorption selectivity is imparted by orienting iodine or a dichroic dye in a stretched PVA or an oriented liquid crystal. The major axis direction of the orientation of the iodine-PVA complex or dichroic dye is called the absorption axis, and the minor axis direction of the iodine-PVA complex or dichroic dye is called the transmission axis. Completely linearly polarized light created by a prism or the like is passed in parallel with the absorption axis / transmission axis, and the absorbance of each can be measured from the light intensity before and after the passage. As described above, in the present invention, the optical characteristics of the elliptical polarizing plate can also be controlled by controlling the absorption characteristics of the polarizing plate. For example, in an elliptical polarizing plate constructed by using retardation plates having the same composition, absorption at a wavelength of around 650 nm (red light) is more than absorption at a wavelength of around 450 nm (blue light) or around 550 nm (green light). By using a polarizing plate having a large property (a polarizing plate having a more bluish hue), the value of P (450) / P (650) in the above formula (1) of this elliptical polarizing plate can be reduced. In particular, the elliptical polarizing plate of the present invention can control the absorbance of the polarizing plate in order to satisfy the optical properties of the above formulas (1), (2) and (4).

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)
Since the polarizing plate has optical characteristics satisfying the above formulas (6) to (8), good light absorption characteristics in the entire visible light range can be obtained.

Further, it is preferable that the absorbance (A1) in the transmission axis direction of the polarizing plate 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)
Since 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.

Further, in order to further increase the absorption of red light in the vicinity of 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), the reflection of red light can be effectively suppressed, and the reflected color at the wavelength of the entire visible light including red light. It is an elliptical polarizing plate that can suppress the coloring of light and impart good display characteristics when used in a display device.

Such light absorption characteristics are achieved, for example, in the case of an iodine PVA polarizing plate by controlling the formation of an I3-PVA complex that exhibits absorption at short wavelengths and an I5-PVA complex that exhibits absorption at long wavelengths. To. Since I3-PVA complex and I5-PVA complexes have a thermal equilibrium state, it is possible to control the temperature and I ₂ concentration / KI concentrations and drying conditions during dyeing, for example, the higher the KI concentration, blue The absorption characteristics of red light are improved compared to light. Further, when the drying temperature is raised, the absorption characteristics of blue light are improved as compared with red light. Further, in the case of the liquid crystal host guest type polarizing plate, the light absorption characteristics can be easily controlled by controlling the addition amount and ratio of the dichroic dye which is a guest molecule. For example, when a plurality of dyes are mixed, by blending more blue dyes than other dyes, only the absorption characteristics of red light can be selectively improved. In the elliptical 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 thinning. Further, a polarizing plate containing a polymer obtained by polymerizing the polymerizable liquid crystal compound and the dichroic dye in a state where the polymerizable liquid crystal compound and the dichroic dye are oriented in the horizontal direction is more suitable in that the compounding of the dye can be controlled. preferable.

The iodine PVA polarizing plate can be used, for example, by a sequential stretching method in which a film-shaped PVA is stretched in a heated state and then subjected to iodine dyeing and cross-linking treatment with boric acid, or while performing iodine dyeing and cross-linking treatment with boric acid in water. It can be produced by a simultaneous stretching method in which PVA in the form of a film is stretched. The draw ratio at this time is preferably 4 to 8 times, and is produced by continuously immersing the PVA film in an aqueous iodine solution and an aqueous boric acid solution to impregnate each molecule. A PVA polarizer can be obtained by removing water by drying the PVA film after dyeing and proceeding with boric acid cross-linking. At this time, 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 adhesively protecting the PVA polarizing element thus obtained on one side or both sides using the transparent base material described above.

When a liquid crystal host-guest type polarizing plate is used, it can be produced by the same method as a retardation plate by mixing a dichroic dye in advance in a layer made of a polymer in an oriented state of a polymerizable liquid crystal compound. However, in order to satisfy the above formulas (6) to (11) at the same time, a highly ordered liquid crystal structure is required. That is, as the polymerizable liquid crystal compound, a smectic liquid crystal compound is preferable to a nematic liquid crystal compound, and a higher-order smectic liquid crystal compound is more preferable. Among them, higher-order smectic liquid crystal compounds forming smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase or smectic L phase More preferably, a higher-order smectic liquid crystal compound forming a smectic B phase, smectic F phase or smectic I phase is further preferable. When the liquid crystal phase formed by the polymerizable liquid crystal compound is these higher-order smectic phases, a liquid crystal cured film having a higher degree of orientation order can be produced, and high polarization performance can be obtained. Further, such a liquid crystal cured film having a high degree of orientation 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 the periodic structure of molecular orientation, and a film having a periodic interval of 3.0 to 6.0 Å can be obtained.

Specific examples of such a compound include a compound represented by the following formula (III) (hereinafter, may be referred to as “compound (III)”) and the like, which constitutes the elliptical 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 independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein the divalent aromatic group or a divalent alicyclic hydrocarbon group is used. 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. Alternatively, the carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be replaced with an oxygen atom or 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. Is.
Y ¹ , Y ² , W ¹ and W ² are independent, single-bonded or divalent linking groups.
V ¹ and V ² represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent independently of each other, and −CH ₂ − constituting the alkanediyl group is −O−, −. It may be replaced with S- or NH-.
U ¹ and U ² represent a polymerizable group or a hydrogen atom independently of each other, and at least one is a polymerizable group.

In compound (III), ^{at least one of X 1} , X ² and X ³ may have a substituent, a 1,4-phenylene group, or a cyclohexane, which may have a substituent. It is a 1,4-diyl group. In particular, X ¹ and X ³ are preferably cyclohexane-1,4-diyl groups which may have a substituent, and the cyclohexane-1,4-diyl group is a trans-cyclohexane-. It is more preferably a 1,4-diyl group. When a trans-cyclohexane-1,4-diyl group structure is contained, smectic liquid crystallinity tends to be easily developed. Further, the substituent arbitrarily contained in the 1,4-phenylene group which may have a substituent or the cyclohexane-1,4-diyl group which may have a substituent is 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. It is preferably unsubstituted.

Y 1 and Y 2, independently of one another, 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 preferred, where Ra and Rb 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 have different bonding methods, smectic liquid crystallinity tends to be easily exhibited.

W ¹ and W ² are preferably single-bonded, -O-, -S-, -COO- or OCO- independently of each other, and more preferably single-bonded 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, decan-1,10-diyl group, tetradecane Examples thereof include a -1,14-diyl group and an icosan-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 linear alkanediyl group having 6 to 12 carbon atoms, the crystallinity is improved and the smectic liquid crystallinity tends to be easily exhibited.
Examples of the substituent arbitrarily contained in the alkanediyl group having 1 to 20 carbon atoms which may have a substituent include a cyano group and a halogen atom such as a chlorine atom and a fluorine atom. , It is preferable that it is unsubstituted, and it is more preferable that it is an unsubstituted and linear alkanediyl group.

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

The ^{polymerizable groups represented by U 1} and U ² may be different from each other, but are preferably the same. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group, an oxetanyl group and the like. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

Examples of such polymerizable liquid crystal compounds include the following.

Among the above-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 the compounds represented by (1-13), formula (1-14) and formula (1-15) is preferable.

The dichroic dye refers to a dye having a property in which the absorbance in the major axis direction and the absorbance in the minor axis direction of the molecule are different.
The dichroic dye preferably has an absorption maximum wavelength (λMAX) in the range of 300 to 700 nm. Examples of such a dichroic dye include an acrydin dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye and an anthraquinone dye, and among them, the azo dye is preferable. Examples of the azo dye include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes and stillbenazo dyes, and bisazo dyes and trisazo dyes are preferable. The dichroic dye may be used alone or in combination, but it is preferable to combine three or more kinds of dichroic dyes, and more preferably to combine three or more kinds of azo dyes. By combining three or more types of dichroic dyes, particularly three or more types of azo dyes, it becomes easy to control the polarization characteristics over the entire visible light range. Further, when combining three or more kinds of dichroic dyes, it is solved the problem of the present invention to use more dichroic dyes that absorb at the longest wavelength than other two kinds of dichroic dyes. Preferred as a means.

Examples of the azo dye include a compound represented by the formula (IV) (hereinafter, may be referred to as “compound (IV)”).
A ¹ (-N = ^{NA 2} ) _p -N = NA ³ (IV)
[In formula (IV),
A ¹ and A ³ are independent of each other, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent. Represents. A ² is a divalent 1,4-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent group which may have a substituent. Represents a heterocyclic group. p represents an integer of 1 to 4. When p is an integer of 2 or more, the plurality of A ^2s may be the same or different from each other. ]

Examples of the monovalent heterocyclic group include a group obtained by removing one hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole and benzoxazole. Examples of the divalent heterocyclic group include a group obtained by removing two hydrogen atoms 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 Examples of the group include 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 trifluoromethyl group and the like. Alkyl fluoride group 1-4; cyano group; nitro group; halogen atom such as chlorine atom, fluorine atom; substituted or unsubstituted amino group such as amino group, diethylamino group and pyrrolidino group (substituted amino group is carbon number) It means an amino group having one or two alkyl groups 1 to 6, or an amino group in which two substituted alkyl groups are bonded to each other to form an alcandiyl group having 2 to 8 carbon atoms. The group is -NH ₂ ). Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group and a hexyl group. The alkanediyl group having 2 to 8 carbon atoms includes an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, and a 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 an azo dye include the following.

In equations (2-1) to (2-6),
B ^{1 to} B ²⁰ are independent of each other, 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, and a substituted or unsubstituted amino group (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 represent an integer of 0 to 3.
If n1 is 2 or more, to each of a plurality of B ² may be the same or different,
If n2 is 2 or more, to each of the plurality of B ⁶ may be the same or different,
If n3 is 2 or more, to each of the plurality of B ⁹ may be the same or different,
When n4 is 2 or more, the plurality of B ^14s may be the same or different.

The 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 diluted with a solvent on a base material or an alignment film formed on the base material (hereinafter, "composition for forming a polarizing film"). A polymer of the polymerizable liquid crystal compound in the orientation state of the mixture containing the polymerizable liquid crystal compound and the dichroic dye can be obtained by applying (also referred to as “material”) and, if necessary, polymerizing the solvent after drying. .. By polymerizing the polymerizable liquid crystal compound while maintaining the horizontally oriented state of the polymerizable liquid crystal compound and the dichroic dye, a liquid crystal cured film maintaining the oriented state is obtained, and the liquid crystal cured film is the host guest. It constitutes a type polarizing plate. At this time, in order to obtain high polarization performance, it is preferable to polymerize the polymerizable liquid crystal compound while maintaining the oriented state in the smectic liquid crystal phase, and polymerize the polymerizable liquid crystal compound while maintaining the oriented state in the higher-order smectic liquid crystal phase. Is more preferable. 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. Examples thereof include those used in the composition for forming an optically anisotropic layer described in the above. Further, as 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 for the retardation plate can be applied. The same applies to the alignment film (composition for forming a photoalignment film) and the like used here.

The content of the polymerizable liquid crystal compound in the polarizing film forming composition (the total amount when a plurality of types are contained) is based on 100 parts by mass of the solid content of the polarizing film forming composition from the viewpoint of developing liquid crystallinity. It is usually 60 to 99 parts by mass, preferably 70 to 95 parts by mass, and more preferably 75 to 90 parts by mass. The content of the dichroic dye (the total amount when a plurality of types are contained) is usually 1 with respect to 100 parts by mass of the solid content of the polarizing film forming composition from the viewpoint of obtaining good light absorption characteristics. It is ~ 30 parts by mass, preferably 2 to 20 parts by mass, and more preferably 3 to 15 parts by mass. The solid content referred to here refers to the total amount of the components excluding the solvent from the composition for forming a polarizing film.

The elliptically polarized light of the present invention is configured to include a polarizing plate and a retardation plate. For example, the elliptically polarized light of the present invention is formed by laminating a polarizing plate and a retardation plate via an adhesive layer or the like. You can get a board.
In one embodiment of the present invention, when the polarizing plate and the retardation plate are laminated, the slow axis (optical axis) of the retardation plate and the absorption axis of the polarizing plate are laminated so as to be substantially 45 °. It is preferable to do so.
The function as an elliptical polarizing plate can be obtained by laminating the slow axis (optical axis) of the retardation plate of the present invention and the absorption axis of the polarizing plate so as to be substantially 45 °. It should be noted that substantially 45 ° is usually in the range of 45 ± 5 °.

The elliptical polarizing plate of the present invention may have a structure provided by a conventional general elliptical polarizing plate, or a polarizing plate and a retardation plate. Such a configuration is used, for example, for the purpose of protecting the surface of an adhesive layer (sheet) for bonding an elliptical polarizing plate to a display element such as an organic EL, a polarizing plate or a retardation plate from scratches and stains. Protective film and the like. Further, the elliptical polarizing plate of the present invention can be cut as necessary and used for a display device such as an organic EL display device or a liquid crystal display device.

In another embodiment of the present invention, a liquid crystal display device and an organic EL display device including the elliptical polarizing plate can be provided. By providing these display devices with the elliptical polarizing plate of the present invention capable of suppressing the coloring of the reflected color at wavelengths in the entire visible light range, good color expression can be exhibited.

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

Preparation of Elliptical Polarizing Plate The following "composition for forming a photoalignment film" and "composition containing a polymerizable liquid crystal compound" were used for producing a retardation plate.

(1) Comparative Example 1
[Preparation of composition for forming a photoalignment film]
5 parts of the following photo-aligning material and 95 parts of cyclopentanone (solvent) were mixed, and the obtained 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 (12.0 parts). 100 parts, 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-A-2010-31223. 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) butane-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals)
Leveling agent: Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)

[Manufacturing method of retardation plate]
Cycloolefin polymer film (COP; ZF-14; manufactured by Nippon Zeon Co., Ltd.) was used with a corona treatment device (AGF-B10; manufactured by Kasuga Electric Works Ltd.) at an output of 0.3 kW and a processing speed of 3 m / min. Processed once. The composition for forming a photoalignment film is coated on a 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 Denki Co., Ltd.). ) Was used to perform polarized UV exposure with an integrated light intensity of 100 mJ / cm ^{2, and an alignment film was formed.} The thickness of the obtained alignment film was measured with an ellipsometer M-220 (manufactured by JASCO Corporation) and found to be 100 nm.

Subsequently, the composition A containing the polymerizable liquid crystal compound prepared above was applied onto the alignment film at a rate of 50 mm / sec with the bar coater wire 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 Denki Co., Ltd.), ultraviolet rays were irradiated from the surface side on which the composition A was applied (integrated light intensity at a wavelength of 313 nm under a nitrogen atmosphere: 500 mJ / cm ^2). ), The retardation plate A including the optically anisotropic layer 1 (phase difference film) was formed. The thickness of the optically anisotropic layer 1 contained in the obtained retardation plate A was measured with a laser microscope (LEXT; manufactured by Olympus Corporation) and found to be 2.28 μm.

[Measurement of optical characteristics of in-plane phase difference value Re (λ)]
In order to measure the in-plane retardation value Re (λ) of the retardation plate A (opticallyotropic layer 1), a sheet-like feeling is formed on the optically anisotropic layer 1 side of the retardation plate A separately produced in the same manner. A pressure adhesive (manufactured by Lintec Co., Ltd., acrylic pressure-sensitive adhesive, colorless and transparent, non-oriented) is bonded, and a glass plate (in-plane phase difference is 0 (zero) at 450 nm, 550 nm and 650 nm) on the adhesive side. ), Then the cycloolefin polymer film was peeled off, and the optically anisotropic layer 1 was transferred to the glass plate to prepare a measurement sample. Using this sample, the in-plane retardation value Re (λ) having a wavelength of 450 nm, a wavelength of 550 nm and a wavelength of 650 nm was measured by a birefringence measuring device (KOBRA-WR; manufactured by Oji Measuring Instruments Co., Ltd.). The results are shown in Table 2.

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

[Polarizing plate I: Manufacture of iodine PVA type 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 pure water at 40 ° C. was further maintained in a tense state. Was immersed in the water for 40 seconds. Then, the dyeing treatment was carried out by immersing the dyeing aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.044 / 5.7 / 100 at 28 ° C. for 30 seconds.
Next, it was immersed in a boric acid aqueous solution having a mass ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100 at 70 ° C. for 120 seconds. Subsequently, after washing with pure water at 8 ° C. for 15 seconds, while holding at a tension of 300 N, the iodine was adsorbed and oriented on the polyvinyl alcohol film by drying at 60 ° C. for 50 seconds and then at 75 ° C. for 20 seconds. 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 laminate 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 above-mentioned water-based adhesive contains 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318; manufactured by Kuraray Co., Ltd.) and a water-soluble polyamide epoxy resin (Smiley's resin 650; manufactured by Sumika Chemtex Co., Ltd.). It was prepared by adding 1.5 parts (an aqueous solution having a solid content concentration of 30%).

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

A pressure-sensitive adhesive (Lintec) so that the angle (θ) between the polarizing plate I and the retardation plate A produced as described above is 45 ° between the absorption axis of the polarizing plate I and the slow axis of the retardation plate A. An elliptical polarizing plate 1 was produced by laminating using an acrylic pressure-sensitive adhesive, colorless and transparent, non-oriented) manufactured by Co., Ltd. The elliptical polarizing plate was further bonded to an aluminum reflective base material (manufacturer: light, product number: HA0323) via a pressure-sensitive adhesive. The bonded object was irradiated with light from a C light source from the polarizing plate side from the 6 ° direction, and the reflection spectrum was measured. From the obtained reflection spectrum and the color matching function of the C light source, the reflection chromaticity a * in the L * a * b * (CIE) color system was calculated. The results are shown in Table 2. The larger the value of the reflected chromaticity a *, the stronger the redness. Table 2 shows the calculated values of P (λ), the values of P (450) / P (650) and 1-P (450).

(2) Example 1
A retardation plate containing an optically anisotropic layer having a thickness of 2.42 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 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 prepare an elliptical polarizing plate 2. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical 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 containing 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 prepare an elliptical polarizing plate 3. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical 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 containing 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 at the time of preparing the composition A containing the 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 prepare an elliptical polarizing plate 4. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical 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, the polymerizable liquid crystal compound A is 10.5 parts by mass, the following polymerizable liquid crystal compound B is 1.5 parts by mass, and the amount of the solvent is 120 parts by mass. An optically anisotropic layer having a thickness of 1.93 μm was prepared by the same method as in Comparative Example 1 except that the wire thickness of the wire bar at the time of coating was set to # 30 by preparing the composition B containing the liquid crystal compound. A retardation plate B containing the above was produced. 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 prepare an elliptical polarizing plate 5. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical 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 set to 115 parts by mass by the same method as in Example 3 except that the thickness of the wire of the wire bar at the time of coating was set to # 30. A retardation plate (type B) containing an optically anisotropic layer having a thickness of 2.01 μm was produced. 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 prepare an elliptical polarizing plate 6. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

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

(8) Comparative Example 3
The thickness of the composition B containing the polymerizable liquid crystal compound was set to 127 parts by mass and the thickness of the wire of the wire bar at the time of coating was set to # 30 by the same method as in Example 3 above. A retardation plate (type B) containing an optically anisotropic layer having a thickness of 1.86 μm was produced. 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 prepare an elliptical polarizing plate 8. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(9) Example 6
In the composition A containing the polymerizable liquid crystal compound of Comparative Example 1, the polymerizable liquid crystal compound A is 9.5 parts by mass, the polymerizable liquid crystal compound B is 2.5 parts by mass, and the amount of the solvent is 105 parts by mass. An optically anisotropic layer having a thickness of 1.72 μm was formed by the same method 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 coating was set to # 20. A retardation plate C containing the mixture was produced. 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 prepare an elliptical polarizing plate 9. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

(10) Example 7
The thickness of the composition C containing the polymerizable liquid crystal compound was set to 100 parts by mass by the same method as in Example 6 except that the thickness of the wire of the wire bar at the time of coating was set to # 20. A retardation plate (type C) containing an optically anisotropic layer having a thickness of 1.76 μm was produced. 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 prepare an elliptical polarizing plate 10. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical 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 set to 110 parts by mass by the same method as in Example 6 except that the thickness of the wire of the wire bar at the time of coating was set to # 20. A retardation plate (type C) containing an optically anisotropic layer having a thickness of 1.61 μm was produced. 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 prepare an elliptical polarizing plate 11. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical 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: a host guest type polarizing plate prepared by the following method was used.
[Preparation of composition A for forming a polarizing film]
The composition A for forming a polarizing film is obtained by mixing the polymerizable liquid crystal compounds C and D shown below, the dichroic dyes A to C, the polymerizable initiator, the leveling agent and the solvent, and stirring the mixture at 80 ° C. for 1 hour. Obtained. When the texture of the composition A for forming a polarizing film was observed with a polarizing microscope while heating the film obtained by drying the solvent after applying the spin coat, the crystal phase was observed between the crystalline phase and the liquid phase due to the temperature change. It was confirmed that the smectic liquid crystal showed three liquid crystal phase states of (62 ° C.) ⇔ smectic B phase (76 ° C.) ⇔ smectic A phase (105 ° C.) ⇔ nematic phase (114 ° C.) ⇔ 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) butane-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)

[Manufacturing method of host guest type polarizing plate]
Triacetyl cellulose film (TAC; KC4UY; manufactured by Konica Minolta Co., Ltd.) is treated once using a corona processing device (AGF-B10; manufactured by Kasuga Electric Works Ltd.) at an output of 0.3 kW and a processing speed of 3 m / min. did. A composition for forming an alignment film photoalignment film prepared in the same manner as in Comparative Example 1 was applied to a corona-treated surface with a bar coater, dried at 80 ° C. for 1 minute, and a polarized UV irradiation device (polarizer unit). Polarized UV exposure was carried out with an integrated light amount of ^{100 mJ / cm 2} using SPOT CURE SP-7 (manufactured by Ushio Denki Co., Ltd.) to form an alignment film. The thickness of the obtained alignment film was measured with an ellipsometer M-220 (manufactured by JASCO Corporation) and found to be 100 nm.

Subsequently, the previously prepared polarizing film forming composition A was applied onto the obtained alignment film at a rate 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 Denki Co., Ltd.), ultraviolet rays were irradiated from the surface side on which the composition A was applied (integrated light amount at a wavelength of 313 nm under a nitrogen atmosphere: 500 mJ / cm ^2). ), To form 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 are oriented in the horizontal direction. The thickness of the obtained polymer was measured with a laser microscope (LEXT; manufactured by Olympus Corporation) and found to be 2.10 μm.

The absorption characteristics of the obtained polarizing plate II were measured in the same manner as in Comparative Example 1. The results are shown in Table 1.
The absorbance at each wavelength that affects the reflected hue was A2 (450) = 1.8, A2 (550) = 2.0, and A2 (650) = 3.2, which were bluish hues. ..

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

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

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

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

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

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

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

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

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

(21) Comparative Example 5
In the composition A containing the polymerizable liquid crystal compound of Comparative Example 1, the polymerizable liquid crystal compound was prepared with 12.0 parts by mass of the polymerizable liquid crystal compound B and 100 parts by mass of the solvent without blending the polymerizable liquid crystal compound A. The composition D containing the composition D was prepared, and the thickness of the wire of the wire bar at the time of coating was set to # 7, but the thickness of the optically anisotropic layer having a thickness of 0.93 μm was included by the same method as in Comparative Example 1. A phase difference plate D was produced. This retardation plate did not satisfy the above formula (3) and did not have anti-wavelength dispersibility. 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 prepare an elliptical polarizing plate 21. The in-plane retardation value Re (λ) and the reflection chromaticity a * of the retardation plate of the obtained elliptical polarizing plate were calculated by the same method as in Comparative Example 1. The results are shown in Table 2.

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

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

In the elliptical 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 high. It was confirmed that it was a very neutral, elliptical polarizing plate with improved redness. On the other hand, in the elliptical polarizing plates of Comparative Examples 1 to 4 having no optical characteristics represented by the following formula (1), the value of the reflection chromaticity a * was large and the reflection color was a reddish elliptical polarizing plate. .. Further, in the elliptical polarizing plates of Comparative Examples 5 and 6 which do not satisfy the optical characteristics represented by the formula (3) and do not have the inverse wavelength dispersibility, the value of the reflection chromaticity a * is very large, and the reflection color is reddish. Was a very strong elliptical 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)

Claims (8)

Includes polarizing plate and retardation plate
The retardation plate is a layer made of a polymer in the oriented state of the polymerizable liquid crystal compound.
An elliptical polarizing plate that satisfies 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)) is / 2, I2 (λ) = (10 -A1 (λ) +10 -A2 (λ)) is / 2, [pi (Λ) = Re (λ) / λ × 2π, A1 (λ) represents the transmissive axial absorbance of the polarizing plate at the wavelength λ, and A2 (λ) represents the absorption axial absorbance of the polarizing plate at the wavelength λ. Re (λ) represents the front retardation of the retardation plate at the wavelength λ, and θ represents the angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate. ] The elliptical polarizing plate according to claim 1, wherein the frontal retardation of the retardation plate at a wavelength of 550 nm satisfies the following formula (5).
130nm ≤ Re (550) ≤ 150nm (5)
[In the formula, Re (550) represents front retardation at a wavelength of 550 nm. ] The elliptical polarizing plate according to claim 1 or 2, wherein the absorption axial absorbance (A2) 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) The elliptical polarizing plate according to any one of claims 1 to 3, wherein the absorbance (A1) in the transmission axis direction 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) The elliptical polarizing plate according to any one of claims 1 to 4, wherein the absorbance (A2) in the absorption axis direction 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) The elliptical polarizing plate according to any one of claims 1 to 5, wherein the angle formed by the absorption axis of the polarizing plate and the slow axis of the retardation plate is substantially 45 °. A liquid crystal display device including the elliptical polarizing plate according to any one of claims 1 to 6. An organic EL display device including the elliptical polarizing plate according to any one of claims 1 to 6.