KR20240064551A - Method for manufacturing optical laminate - Google Patents

Abstract

[Problem] To provide a method for manufacturing an optical laminate with small variations in optical properties.
[Solution] (a1) A long disk optical film having an upper surface and a lower surface, wherein the angle α ₁ [°] of the optical axis with respect to the width direction when viewed from the top surface is -1° to 1° in the central portion of the width direction. , a process of obtaining a first optical film and a second optical film by cutting an optical film that changes from the center portion in the width direction to both ends in the width direction to be divided into plural pieces in the width direction, (c12) dividing the original first polarizing film into two pieces in the width direction. A process of obtaining two sheets of the first polarizing film by cutting to divide, (d1) A process of obtaining an optical laminate by bonding the first optical film and the first polarizing film with their upper surfaces facing each other so that the width direction and the forward direction of the length match each other. Method for manufacturing an optical laminate having.

Description

Method for manufacturing optical laminates {METHOD FOR MANUFACTURING OPTICAL LAMINATE}

The present invention relates to a method of manufacturing an optical laminate.

In a liquid crystal display device (LCD), it is known that the efficiency of light use can be improved by using a reflective polarizer between the panel and the backlight. Regarding the reflective polarizer, the efficiency of light use can be further improved by using a polarizing film or a retardation film bonded thereto. Conventionally, an optical laminate is known in which a polarizing film or a retardation film containing a polymer of a polymerizable liquid crystal compound is laminated on a reflective polarizing plate (for example, Patent Document 1).

Patent Document 1: Japanese Patent Publication No. 2018-124467

The purpose of the present invention is to provide a method for manufacturing an optical laminate with small variations in optical properties.

The present invention provides the following.

[1] (a1) A long disk optical film having an upper surface and a lower surface, wherein the angle α ₁ [°] of the optical axis with respect to the width direction when viewed from the top surface is -1° to 1° in the central portion of the width direction, The optical film, which changes from the central part in the width direction to both ends in the width direction, is cut to be divided into plural parts in the width direction, and the average value α _{1 m} of the angle α ₁ [°] formed with respect to the width direction of the optical axis when viewed from the top is positive. A process of obtaining an optical film and a second optical film in which the average value α _{2 m} of the angle α ₂ [°] formed with respect to the width direction of the optical axis when viewed from the top is negative,

(c11) a process of preparing a long disk first polarizing film and a disk second polarizing film having an upper surface and a lower surface,

(c12) A process of cutting the original first polarizing film into two pieces in the width direction to obtain two sheets of the first polarizing film,

(c13) A process of cutting the original second polarizing film into two pieces in the width direction to obtain two sheets of the second polarizing film,

(d1) A process of obtaining an optical laminate by bonding the first optical film and the first polarizing film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction coincide with each other,

(e1) A process of obtaining an optical laminate by bonding the second optical film and the second polarizing film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction coincide with each other.

With

In the above step (c11), the angle β ₁ [°] formed by the first circular polarizing film with respect to the width direction of the absorption axis when viewed from the top satisfies the following equation (i), and the second circular polarizing film satisfies the equation (i) when viewed from the upper plane. A method of manufacturing an optical laminate in which the angle β ₂ [°] formed with respect to the width direction of the absorption axis satisfies the following formula (ii).

β ₁ =-(A ₁ /2)(1.0±0.3) (i)

β ₂ =-(A ₂ /2)(1.0±0.3) (ii)

[In the above formula (i), A ₁ represents the absolute value of the angle α _1a , and in the above formula (ii), A ₂ represents the absolute value of the angle α _2a .]

here,

The angle α _1a is the angle when the absolute value becomes the maximum among the angles α ₁ of the first optical film,

The angle α _2a is the angle when the absolute value becomes the maximum among the angles α ₂ of the second optical film.

Regarding process (a1),

The disk optical film is, for example, a long reflective polarizer. The optical axis is the reflection axis. A reflective polarizing plate is a film that has an optical function of reflecting polarized light components parallel to the reflection axis and transmitting polarized light components orthogonal to the reflection axis.

The disk optical film is, for example, a long retardation plate. This optical axis is the slow axis or fast axis. Examples of the original optical film include polycarbonate-based resin films, cycloolefin-based resin films, and polyester-based resin films. For example, they are biaxially stretched films obtained by biaxial stretching.

The raw optical film may be cut so as to be divided into two along the central portion in the width direction. The raw optical film may be cut so as to be divided into three lengthwise sections: a central portion in the width direction, an end portion in the width direction, and an end portion in the other width direction. In this case, both ends in the width direction become the first optical film and the second optical film, respectively.

Regarding process (c1),

The elongated first polarizing film usually contains a polymer of a polymerizable liquid crystal compound. The angle of the absorption axis is usually constant over the entire width, and its deviation is within the range of ±1°.

The elongated second polarizing film usually contains a polymer of a polymerizable liquid crystal compound. The angle of the absorption axis is usually constant over the entire width, and its deviation is within the range of ±1°.

The elongated first polarizing film and the elongated second polarizing film are each formed by forming an alignment film on a elongated base film, and forming a film composed of a dichroic dye and a polymer of a polymerizable liquid crystal compound on the alignment film. It can be prepared by

Regarding process (d1),

Among the upper and lower surfaces of the first optical film, the upper surface is a bonding surface bonded to the first polarizing film, and the lower surface is the opposite surface. Among the upper and lower surfaces of the first polarizing film, the upper surface is a bonding surface bonded to the first optical film, and the lower surface is the opposite surface.

Regarding process (e1),

Among the upper and lower surfaces of the second optical film, the upper surface is a bonding surface bonded to the second polarizing film, and the lower surface is the opposite surface. Among the upper and lower surfaces of the second polarizing film, the upper surface is a bonding surface bonded to the second optical film, and the lower surface is the opposite surface.

In addition, as the raw optical film used in [1] (a1) above, the angle α ₁ [°] is -1° to 1°, preferably 0°, in the center portion in the width direction, and is formed from the center portion in the width direction to one end. An example is an optical film that monotonically increases and monotonically decreases from the central portion in the width direction to the other end of the width direction.

[2] When the width of the first optical film is B ₁ [mm], the respective widths of the second optical film, the first polarizing film, and the second polarizing film are within the range of 0.7B ₁ to 1.3B ₁ [1] ] The manufacturing method of the optical laminated body described in.

[3] The method for manufacturing an optical laminate according to [1] or [2], wherein the bonding in the step (d1) and the step (e1) includes an adhesive layer interposed between opposing upper surfaces.

[4] With respect to the first optical film and the second optical film, the angle α ₁ and the angle α ₂ with the maximum absolute value are determined, and the step (b1) is made to be the angle α _1a and the angle α _2a , respectively,

In the step (b1), the angle α _1a is determined to be 5° or less, and the angle α _2a is determined to be -5° or more.

[5] (a2) A long disk optical film having an upper surface and a lower surface, wherein the angle α ₁ [°] of the optical axis with respect to the width direction when viewed from the top surface is preferably -1° to 1° in the central portion of the width direction. The average value of the angle α ₁ [°] formed with respect to the width direction of the optical axis when viewed from the top by cutting the optical film, which is 0° and changes from the center of the width direction to both ends of the width direction, to be divided into multiple parts in the width direction. A process of obtaining a first optical film in which α _1m is positive, and a second optical film in which the average value α _2m of the angle α ₂ [°] formed with respect to the width direction of the optical axis when viewed from the top is negative,

(c21) a process of preparing a long disk first retardation film and a disk second retardation film having an upper surface and a lower surface,

(c22) A process of cutting the original first retardation film into two pieces in the width direction to obtain two sheets of the first retardation film,

(c23) A process of cutting the original second retardation film into two pieces in the width direction to obtain two sheets of the second retardation film,

(d2) A process of obtaining an optical laminate by bonding the first optical film and the first retardation film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction coincide with each other,

(e2) A process of obtaining an optical laminate by bonding the second optical film and the second retardation film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction coincide with each other.

With

In the above step (c21), the angle γ ₁ [°] formed by the disk first retardation film with respect to the width direction of the slow axis when viewed from the top satisfies the following equation (iii) or (iv), and the disk second retardation film satisfies the following formula: A method of manufacturing an optical laminate wherein the angle γ ₂ [°] formed with respect to the width direction of the slow axis when viewed from the top satisfies the following equation (v) or (vi).

γ ₁ =-(A ₁ /2)(1.0±0.3)+45 (iii)

γ ₁ =-(A ₁ /2)(1.0±0.3)-45 (iv)

γ ₂ =-(A ₂ /2)(1.0±0.3)+45 (v)

γ ₂ =-(A ₂ /2)(1.0±0.3)-45 (vi)

[In the above formulas (iii) and (iv), A ₁ represents the absolute value of the angle α _1a , and in the above formulas (v) and (vi), A ₂ represents the absolute value of the angle α _2a .]

here,

Regarding process (c2),

The elongated first retardation film usually contains a polymer of a polymerizable liquid crystal compound. The angle of the slow axis of the first retardation film is generally approximately constant over the entire width, and its change, that is, the difference between the maximum and minimum values, is usually within the range of ±2°, preferably ±1°.

The elongated second retardation film usually contains a polymer of a polymerizable liquid crystal compound. The angle of the slow axis of the second retardation film is generally roughly constant over the entire width, and its change, that is, the difference between the maximum and minimum values, is usually within the range of ±2°, preferably ±1°.

The elongated first retardation film and the elongated second retardation film can be prepared by the process of forming an alignment film on a elongated base film, and forming a film made of a polymer of a polymerizable liquid crystal compound on this alignment film. there is.

Regarding process (d2),

Among the upper and lower surfaces of the first optical film, the upper surface is a bonding surface bonded to the first retardation film, and the lower surface is the opposite surface. Among the upper and lower surfaces of the first retardation film, the upper surface is a bonding surface bonded to the first optical film, and the lower surface is the opposite surface.

Regarding process (e1),

Among the upper and lower surfaces of the second optical film, the upper surface is a bonding surface bonded to the second retardation film, and the lower surface is the opposite surface. Among the upper and lower surfaces of the second retardation film, the upper surface is a bonding surface bonded to the second optical film, and the lower surface is the opposite surface.

In addition, in the above [5] (a2), in the original optical film, the angle α ₁ [°] is -1° to 1°, preferably 0°, in the center portion of the width direction, and is 0° in the center portion of the width direction. An example is an optical film that monotonically increases toward one end and monotonically decreases from the central portion in the width direction to the other end in the width direction.

[6] When the width of the first optical film is B ₁ [mm], the respective widths of the second optical film, the first phase contrast film, and the second phase contrast film are within the range of 0.7B ₁ to 1.3B ₁ [5] ] The manufacturing method of the optical laminated body described in.

[7] The method for producing an optical laminate according to [5] or [6], wherein the bonding in the step (d2) and the step (e2) includes an adhesive layer interposed between opposing upper surfaces.

[8] For the first optical film and the second optical film, determine the angle α ₁ and angle α ₂ whose absolute value is the maximum, and have a step (b2) of making them angle α _1a and angle α _2a , respectively,

In the step (b2), the angle α _1a is determined to be 5° or less, and the angle α _2a is determined to be -5° or more.

According to the manufacturing method of the present invention, an optical laminate with small variations in optical properties can be provided.

1 is a diagram schematically showing an example of the axis relationship of a reflective polarizing plate.
FIG. 2 is a diagram schematically showing an example of a manufacturing process for a reflective polarizing plate.
FIG. 3 is a diagram showing (a) the axial relationship and (b) the transmittance difference in an optical laminate obtained by laminating a reflective polarizing plate and a polarizing film.
FIG. 4 is a diagram showing (a) axial relationship and (b) ellipticity in an optical laminate obtained by laminating a reflective polarizing plate and a retardation film.
Fig. 5 is a top view schematically showing the manufacturing method of the optical laminated body of the first embodiment.
Fig. 6 is a top view schematically showing an example of the axial relationship of the optical laminated body obtained by the second embodiment.
Fig. 7 is a top view schematically showing another example of the axial relationship of the optical laminated body obtained according to the second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all drawings below, the scale of each component is appropriately adjusted to make it easier to understand, and the scale of each component shown in the drawings does not necessarily match the scale of the actual component.

[Method for manufacturing optical laminate]

The method for manufacturing an optical laminate of the present invention produces an optical laminate by bonding a polarizing film or a retardation film to a reflective polarizing plate. Specifically, an optical laminate is manufactured by bonding a long polarizing film or retardation film to a long reflective polarizing plate with the longitudinal direction aligned with this.

A reflective polarizer is a polarization conversion element that has the characteristic of transmitting linearly polarized light in one vibration direction and reflecting linearly polarized light in the other vibration direction, and has the function of separating natural light into transmitted polarized light and reflected polarized light or reflected scattered light. . The reflective polarizing plate used in the present invention is not limited as long as it has the above characteristics. In the present invention, for example, a biaxially stretched film can be used as a reflective polarizer.

The present inventors have discovered a problem that, in a reflective polarizing plate made of a biaxially stretched film, there is variation in the direction of the reflection axis. This variation causes variation in the optical properties in the optical laminate.

FIG. 1 is a diagram schematically showing an example of the relationship between the direction of the reflection axis The present inventors have found that the reflection axis Although the directions are the same, the deviation from the width direction of the reflection axis

FIG. 2 is a schematic diagram estimating the cause of variation in the direction of the reflection axis (X) in the reflective polarizer 10. The elongated reflective polarizing plate 10 is typically manufactured as a biaxially stretched film by stretching the raw material film 20 in the longitudinal and transverse directions while conveying it, as shown in FIG. 2 . When stretching the raw material film 20 in the width direction, the force in the width direction is usually not equal, so the display line that was aligned with the width direction before stretching is changed into a curved shape centered around the center area by stretching in the width direction. Therefore, it is assumed that the width direction and the direction of the reflection axis

When obtaining an optical laminate by laminating a reflective polarizer and a polarizing film, the smaller the absolute value of the angle between the reflection axis of the reflective polarizer and the absorption axis of the polarizing film, the lower the light utilization efficiency, that is, the ability to extract the circularly polarized component of the incident light. The ratio of light available can be improved. FIG. 3(a) is a diagram showing the axial relationship in an optical laminate obtained by laminating a reflective polarizing plate 10 and a polarizing film 30. In the obtained optical laminate, the angle formed by the absorption axis E of the polarizing film 30 with respect to the reflection axis X of the reflective polarizing plate 10 when viewed from the side of the reflective polarizing plate 10 is the angle ( θ) (clockwise is positive). Figure 3(b) is a graph showing the angle θ on the horizontal axis and the calculated value of the transmittance difference of the optical laminate on the vertical axis. From the graph shown in FIG. 3(b), it can be seen that as the angle θ increases, the transmittance increases, that is, the light leak from the optical laminate increases.

When an optical laminate is obtained by laminating a reflective polarizer and a retardation film, light use efficiency can be improved as the absolute value of the angle between the polarization axis of the reflective polarizer and the slow axis of the retardation film approaches 45°. FIG. 4(a) is a diagram showing the axial relationship in an optical laminate obtained by stacking a reflective polarizing plate 10 and a retardation film 80. In the obtained optical laminate, when viewed from the side of the reflective polarizer 10, the angle formed by the retardation film 80 with respect to the reflection axis (X) of the reflective polarizer 10 is 45°. , the deviation of the reflection axis Figure 4(b) is a graph showing the angle θ on the horizontal axis and the calculated value of the ellipticity of the optical laminate on the vertical axis. From the graph shown in FIG. 4(b), it can be seen that as the angle θ increases, the ellipticity decreases, that is, the light conversion efficiency in the optical laminate decreases.

The present invention provides a method for manufacturing an optical laminate that can align and bond the absorption axis of the polarizing film or the slow axis of the retardation film to be bonded with high precision even if there is the above-mentioned variation in the direction of the reflection axis in the reflective polarizer. to provide. Hereinafter, a first embodiment according to a method of manufacturing an optical laminate by bonding a polarizing film to a reflective polarizing plate and a second embodiment according to a method of manufacturing an optical laminate by bonding a retardation film to a reflective polarizing plate will be described. .

[First Embodiment]

The manufacturing method of the optical laminate of the first embodiment includes:

(a1) A long disk-reflective polarizer having an upper surface and a lower surface is cut into two parts in the width direction, and the average value α _{1 m} of the angle α ₁ [°] formed with respect to the width direction of the reflection axis when viewed from the top surface is positive. 1 A process of obtaining a reflective polarizer and a second reflective polarizer in which the average value α _2m of the angle α ₂ [°] formed with respect to the width direction of the reflection axis when viewed from the top is negative,

(b1) For the first reflective polarizer and the second reflective polarizer, determining angle α ₁ and angle α ₂ with the maximum absolute value, and making them angle α _1a and angle α _2a , respectively,

(c11) a process of preparing a long disk first polarizing film and a disk second polarizing film having an upper surface and a lower surface,

(c12) A process of cutting the original first polarizing film into two pieces in the width direction to obtain two sheets of the first polarizing film,

(c13) A process of cutting the original second polarizing film into two pieces in the width direction to obtain two sheets of the second polarizing film,

(d1) A process of obtaining an optical laminate by bonding the first reflective polarizer and the first polarizer film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction coincide with each other,

(e1) Process of obtaining an optical laminate by bonding the second reflective polarizer and the second polarizer film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction match each other.

With

The disk first polarizing film and the disk second polarizing film include a polymer of a polymerizable liquid crystal compound,

In the above step (c11), the angle β ₁ [°] formed by the first polarizing film with respect to the width direction of the absorption axis when viewed from the top satisfies the above formula (i), and the second polarizing film is formed with an angle β 1 [°] when viewed from the top. The angle β ₂ [°] formed with respect to the width direction of the absorption axis satisfies equation (ii) above. That is, the angle β ₁ [°] satisfies the following equation (i'), and the angle β ₂ [°] satisfies the following equation (ii').

-1.3(A _1/2 )≤β ₁ ≤-0.7(A _1/2 ) (i')

-1.3(A ₂ /2)≤β ₂ ≤-0.7(A ₂ /2) (ii')

[In the above formula (i'), A ₁ represents the absolute value of the angle α _1a , and in the above formula (ii'), A ₂ represents the absolute value of the angle α _2a .]

Fig. 5 is a top view schematically showing the manufacturing method of the optical laminated body of the first embodiment.

<Process (a1)>

As shown in FIG. 5, in step (a1), a disk reflective polarizer 10 is prepared, and it is cut into two parts in the width direction to form a first reflective polarizer 11 and a second reflective polarizer ( 12) is obtained. The disc-reflective polarizer 10, the first reflective polarizer 11, and the second reflective polarizer 12 (hereinafter, collectively referred to as “reflective polarizer”) are omitted in Figure 5, but are shown in a long form. It's my brother. Regarding the reflective polarizing plate, the surface shown in Fig. 5 is referred to as the upper surface, and the surface opposite to the upper surface is referred to as the lower surface. Additionally, the direction toward the top in Fig. 5 is referred to as the longitudinal direction, and the direction toward the bottom in Fig. 5 is referred to as the longitudinal direction. In Fig. 5, the reflection axis It is assumed that the reflective polarizing plate is conveyed in the forward longitudinal direction during the manufacturing process. The reflective polarizing plate may be transported in the reverse direction in the manufacturing process. The width of the disc reflective polarizer 10 is set to W [mm].

In step (a1), the cut piece on the right side when viewed from the top of the drawing, which is obtained by cutting into two parts, is used as the first reflective polarizing plate 11, and the cut piece on the left side when viewed from the top side of the drawing is used as the second. It is used as a reflective polarizer (12). The position at which the disc-reflective polarizer 10 is divided into two is not limited, but is preferably the center position in the width direction (hereinafter also referred to as the “W/2” position), and is (W/2) from the center position in the width direction. It is okay to have a position that is shifted left and right within the range of ×0.3. If the width of the first reflective polarizer 11 is B ₁ [mm] and the width of the second reflective polarizer 12 is B ₂ [mm], B ₂ is preferably 0.7B ₁ or more and 1.3B. It is within the range of ₁ or less.

In the disc-reflective polarizer 10, the reflection axis The average value α _1m of the angle α ₁ [°] formed with respect to is positive. In the second reflective polarizing plate 12, the average value α _{2 m} of the angle α ₂ [°] formed with respect to the width direction of the reflection axis X when viewed from the top is negative. In this specification, regarding angles, positive values represent clockwise angles, negative values represent counterclockwise angles, and are expressed in the range of -90° and 90° or less.

Regarding the first reflective polarizer 11, the definition of the angle α ₁ [°] formed with respect to _the width direction of the reflection axis

The reflection axis (X) of the first reflective polarizer 11 is curved because the angle of the reflection axis (X) is different at each position. Regarding the first reflective polarizer 11 shown in FIG. 5, the angle α ₁ [°] formed with respect to the width direction of the reflection axis X is approximately 0° at the left end 11l and at the right end 11r. It becomes a large value in quantity. The average value α _{1 m} is the average value of the angle α ₁ of 10 points determined by dividing it equally to include 2 points at both ends in the width direction. When viewed from the top, when the reflection axis (X) goes down to the right, the average value becomes positive. Therefore, there are cases where it is possible to determine whether the average value is positive or negative even if the average value is not calculated.

The reflection axis (X) of the second reflective polarizer 12 is also curved because the angle of the reflection axis . Regarding the second reflective polarizer 12 shown in FIG. 5, the angle α ₂ [°] formed with respect to the width direction of the reflection axis X is approximately 0° at the right end 12r and at the left end 12l. It becomes a large negative value. The average value α _{2 m} is the average value of the angle α ₂ [°] of 10 points determined by dividing it equally to include 2 points at both ends in the width direction. When viewed from the top, if the reflection axis goes down to the left, the average value becomes negative. Therefore, there are cases where it is possible to determine whether the average value is positive or negative even if the average value is not calculated.

The disk reflective polarizer 10 can be prepared, for example, as a roll, and may be rolled out, cut, and divided into a first reflective polarizer 11 and a second reflective polarizer 12. The first reflective polarizing plate 11 and the second reflective polarizing plate 12 may be once wound into a roll and configured as a roll body before being provided to the next process.

<Process (b1)>

In step (b1), with respect to the first reflective polarizer 11 and the second reflective polarizer 12, the angle α ₁ and angle α ₂ with the maximum absolute value are determined, and are designated as angle α _1a and angle α _2a, respectively. Do this. The angle α _1a and the angle α _2a are required when determining A ₁ and A ₂ used in the above formula (i) and the above equation (ii). The angle _α1 and angle _α2 , which have the maximum absolute value, are taken as the maximum value at 10 points determined by the same method as when calculating the average value. In Fig. 5, for the first reflective polarizer 11, the absolute value of the angle α ₁ of the reflection axis 12l), the absolute value of the angle α ₂ of the reflection axis (X) becomes the maximum.

The angle α _1a and the angle α _2a may be determined by measurement, or if the angle α _1a and the angle α _2a can be considered to depend on the type of the disc-reflective polarizer 10, they may be determined in advance depending on the type. You can leave it at that. For example, when using the disc-reflective polarizing plate 10 with a width W of 1000 mm or more and 15000 mm or less, the angle α _1a may be set in advance to 5° and the angle α _2a may be set to -5°.

<Process (c11)>

As shown in FIG. 5, in step (c11), the original first polarizing film 50 and the original second polarizing film 60 are prepared. The first circular polarizing film 50 and the second circular polarizing film 60 are elongated. A roll body in which a long polarizing film is wound on a roll may also be used. In FIG. 5, the fact that the original first polarizing film 50 and the original second polarizing film 60 are elongated is omitted and schematically shown. The angle β ₁ [°] of the disk first polarizing film 50 with respect to the width direction of the absorption axis E when viewed from the top satisfies the above equation (i), and the disk second polarizing film 60 has The angle β ₂ [°] formed with respect to the width direction of the absorption axis E when viewed from the top satisfies the above equation (ii). That is, the angle β ₁ [°] satisfies the following equation (i'), and the angle β ₂ satisfies the following equation (ii').

-1.3×α _1m ≤β ₁ ≤-0.7×α _1m (i')

-0.7×α _2m ≤β ₂ ≤-1.3×α _2m (ii')

In the above formula (i), A ₁ represents the absolute value of the angle α _1a , and in the above formula (ii), A ₂ represents the absolute value of the angle α _2a . In the example shown in FIG. 5, A ₁ is _the absolute value of the angle α _1a of the reflection axis It is the absolute value of the angle α _2a of the reflection axis (X).

<Process (c12)>

As shown in FIG. 5, in step (c12), the original first polarizing film 50 is cut into two pieces in the width direction to obtain two sheets of first polarizing film 51 and 52. In the two first polarizing films 51 and 52, the angle formed with respect to the width direction of the absorption axis E of the original second polarizing film 50 is maintained. The position at which the original first polarizing film 50 is divided into two is not limited, but if the width of the original first polarizing film 50 is D ₁ [mm], the center position in the width direction (hereinafter referred to as [D _1/2 ] position), and may be a position that is shifted left and right within a range of (D _1/2 ) x 0.3 from the center position in the width direction. If the width of the first reflective polarizer 11 is B ₁ and the widths of the first polarizer 51 and the second polarizer 52 are D ₁₁ [mm] and D ₁₂ [mm], respectively, then D ₁₁ [mm] and D ₁₂ [mm] are each preferably within the range of 0.7B ₁ or more and 1.3B ₁ or less.

<Process (c13)>

As shown in FIG. 5, in step (c13), the original second polarizing film 60 is cut into two pieces in the width direction to obtain two sheets of second polarizing film 61 and 62. In the two second polarizing films 61 and 62, the angle formed with the width direction of the absorption axis E of the original second polarizing film 60 is maintained. The position at which the original second polarizing film 60 is divided into two is not limited, but if the width of the original second polarizing film 50 is D ₂ [mm], the center position in the width direction (hereinafter referred to as [D _2/2 ] position), and may be a position that is shifted left and right within a range of (D ₂ /2) x 0.3 from the center position in the width direction. If the width of the first reflective polarizer 11 is B ₁ and the widths of the second polarizer 51 and 52 are D ₂₁ [mm] and D ₂₂ [mm], respectively, then D ₂₁ [mm] and D ₂₂ [mm] are each preferably within the range of 0.7B ₁ or more and 1.3B ₁ or less.

<Process (d1)>

As shown in FIG. 5, in step (d1), the first reflective polarizing plate 11 and the first polarizing films 51 and 52 are bonded with their upper surfaces facing each other so that their width directions and longitudinal forward directions match each other. Thus, the optical laminate 71 is obtained. Specifically, the first reflective polarizing plate 11 and the first polarizing films 51 and 52 can be bonded by passing them through a bonding roll while conveying them in the longitudinal direction. In step (d1), the first polarizing film bonded to the first reflective polarizing plate 11 may be any one of the two first polarizing films 51 and 52. In FIG. 5 , the optical laminate 71 is shown in a top view viewed from the first reflective polarizing plate 11 side. The first reflective polarizing plate 11 and the first polarizing films 51 and 52 may be bonded through an adhesive layer.

<Process (e1)>

As shown in FIG. 5, in step (e1), the second reflective polarizing plate 12 and the second polarizing films 61 and 62 are bonded with their upper surfaces facing each other so that their width directions and longitudinal forward directions match each other. Thus, the optical laminate 72 is obtained. Specifically, the second reflective polarizing plate 12 and the second polarizing films 61 and 62 can be bonded by passing them through a bonding roll while conveying them in the longitudinal direction. In FIG. 5 , the optical laminate 72 is shown in a top view viewed from the second reflective polarizing plate 12 side. The second reflective polarizer 12 and the second polarizer films 61 and 62 may be bonded through an adhesive layer.

<Optical laminate>

As can be seen from FIG. 5, according to the first embodiment, a reflective polarizing plate and a polarizing film are laminated, and the optical lamination has a small deviation between the reflection axis (X) of the reflective polarizing plate and the absorption axis (E) of the polarizing film. Sieves 71 and 72 can be obtained. In step (c11), the original first polarizing film 50 is prepared so that the direction of its absorption axis E is adjusted to satisfy equation (i), thereby preparing the optical laminate 71 after bonding. This is because the occurrence of misalignment with the reflection axis (X) of the first reflective polarizer 11 can be reduced. In addition, with respect to the original second polarizing film 60, the direction of the absorption axis E is prepared so that the direction of the absorption axis E is adjusted to satisfy equation (ii), thereby forming a second reflective film in the optical laminate 72 after bonding. This is because the occurrence of misalignment with the reflection axis (X) of the polarizing plate 12 can be reduced.

In addition, in this embodiment, the original first polarizing film 50 and the original second polarizing film 60 are configured to contain a polymer of a polymerizable liquid crystal compound, so that the direction of the absorption axis E with respect to the width direction Since can be arbitrarily adjusted, it becomes easy to adjust to satisfy the above equation (i) or equation (ii).

[Second Embodiment]

The manufacturing method of the optical laminate of the second embodiment includes:

(a2) A long disk-reflective polarizer having an upper surface and a lower surface is cut into two parts in the width direction, and the average value α _{1 m} of the angle α ₁ [°] formed with respect to the width direction of the reflection axis when viewed from the top surface is positive. 1 A process of obtaining a reflective polarizer and a second reflective polarizer in which the average value α _2m of the angle α ₂ [°] formed with respect to the width direction of the reflection axis when viewed from the top is negative,

(b2) For the first reflective polarizer and the second reflective polarizer, determining angle α ₁ and angle α ₂ with the maximum absolute value, and making them angle α _1a and angle α _2a , respectively,

(c21) a process of preparing a long disk first retardation film and a disk second retardation film having an upper surface and a lower surface,

(c22) A process of cutting the original first retardation film into two pieces in the width direction to obtain two sheets of the first retardation film,

(c23) A process of cutting the original second retardation film into two pieces in the width direction to obtain two sheets of the second retardation film,

(d2) a process of obtaining an optical laminate by bonding the first reflective polarizer and the first retardation film with their upper surfaces facing each other so that the width direction and the forward length direction match each other,

(e2) A process of obtaining an optical laminate by bonding the second reflective polarizer and the second retardation film with their upper surfaces facing each other so that their width directions and longitudinal forward directions match each other.

With

The original first retardation film and the original second retardation film include a polymer of a polymerizable liquid crystal compound,

In the step (c21), the angle γ ₁ [°] formed by the first disc retardation film with respect to the width direction of the slow axis when viewed from the top satisfies the above equation (iii) or the above equation (iv), and the second disc retardation film The angle γ ₂ [°] formed by the retardation film with respect to the width direction of the slow axis when viewed from the top satisfies the above equation (v) or the above equation (vi). That is, the angle γ ₁ [°] satisfies the following formula (iii') or the following formula (iv'), and the angle γ ₂ [°] satisfies the following formula (v') or the following formula (vi').

-1.3×α _1m +45≤γ ₁ ≤-0.7×α _1m +45 (iii')

-1.3×α _1m -45≤γ ₁ ≤-0.7×α _1m -45 (iv')

-0.7×α _2m +45≤γ ₂ ≤-1.3×α _2m +45 (v’)

_{-0.7 ​ ​ ​ ​} In v') and (vi'), A ₂ represents the absolute value of angle α _2a .]

<Process (a2)>

Step (a2) is the same as step (a1) of the first embodiment.

<Process (b2)>

Step (b2) is the same as step (b1) in the first embodiment.

<Process (c21)>

The step (c21) is different from the step (c11) of the first embodiment only in that the master first retardation film and the master second retardation film are prepared instead of the master first polarizing film and the master second polarizing film.

<Process (c22)>

The step (c22) differs from the step (c12) of the first embodiment in that, instead of the original first polarizing film, the original first retardation film is cut into two pieces in the width direction to obtain two sheets of the first retardation film.

<Process (c23)>

The step (c23) differs from the step (c13) of the first embodiment in that, instead of the original second polarizing film, the original second retardation film is cut into two pieces in the width direction to obtain two sheets of the second retardation film.

<Process (d2)>

The step (d2) differs from the step (d1) of the first embodiment only in that a first retardation film is used instead of the first polarizing film.

<Process (e2)>

The step (e2) differs from the step (e1) of the first embodiment only in that a second retardation film is used instead of the second polarizing film.

<Optical laminate>

Fig. 6 shows the axis relationship as seen from the first reflective polarizing plate side regarding the optical laminate obtained in step (d2). Figure 6(a) shows an example of the axis relationship in the optical laminate 81 obtained when the slow axis F of the disk first retardation film satisfies the relationship of equation (iii), and Figure 6(b) ) shows an example of the axis relationship in the optical laminate 82 obtained when the slow axis F of the original first retardation film satisfies the relationship of equation (iv). Additionally, Fig. 7 shows the axis relationship as seen from the second reflective polarizing plate side with respect to the optical laminate obtained in step (e2). Figure 7(a) shows an example of the axis relationship of the optical laminate 91 obtained when the slow axis F of the disk second retardation film satisfies the relationship of equation (v), and Figure 7(b) shows An example of the axis relationship of the optical laminate 92 obtained when the slow axis F of the disk second retardation film satisfies the relationship of equation (vi) is shown.

As can be seen from FIGS. 6 and 7, according to the second embodiment, the reflective polarizer and the retardation film are stacked, and the angle formed by the reflection axis (X) of the reflective polarizer and the slow axis (F) of the retardation film It is possible to obtain optical laminates 81, 82, 91, and 92 in which the absolute value of has a small deviation from 45°. This is achieved by preparing, in step (c2), the original first retardation film whose direction of slow axis F is adjusted to satisfy equation (iii) or (iv), thereby forming an optical laminate after bonding. This is because in (81, 82), the deviation of the absolute value of the angle formed with the reflection axis (X) of the first reflective polarizer from 45° can be reduced. In addition, with respect to the original second retardation film, by preparing one in which the direction of the slow axis F is adjusted to satisfy equation (v) or equation (vi), in the optical laminate 91, 92 after bonding This is because the deviation of the absolute value of the angle formed with the reflection axis (X) of the second reflective polarizing plate from 45° can be reduced.

In addition, in this embodiment, by forming the first retardation film and the second retardation film to include a polymer of a polymerizable liquid crystal compound, the direction of the slow axis F with respect to the width direction can be adjusted arbitrarily, Adjustment to satisfy the above formulas (iii) to (vi) becomes easy.

[Reflective polarizer]

A reflective polarizer is also called a brightness enhancing film, and a polarization conversion element is used that has the function of separating light emitted from a light source (backlight) into transmission polarization and reflection polarization or scattering polarization. As described above, by arranging the reflective polarizer and the polarizer in a predetermined relationship, the emission efficiency of linearly polarized light emitted from the polarizer can be improved by using retroactive light, which is reflected polarization or scattered polarization. For example, a reflective polarizer is laminated in contact with the first adhesive layer.

The reflective polarizer may be, for example, an anisotropic reflective polarizer. An example of an anisotropic reflective polarizer is an anisotropic multiple thin film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction, and a specific example is DBEF manufactured by 3M (Japanese Patent Publication No. 4 -268505 Gazette, etc.). This reflective polarizing plate is a reflective polarizing plate formed by stretching a multilayer laminate composed of at least two thin films with different refractive index anisotropy. Therefore, this reflective polarizing plate has at least two layers of thin films, and the stretched thin films of at least two layers have different refractive index anisotropies.

Another example of an anisotropic reflective polarizer is a composite of a cholesteric liquid crystal layer and a λ/4 plate, a specific example of which is PCF manufactured by Nitto Denko Co., Ltd. (Japanese Patent Application Laid-Open No. 11-231130, etc.). Another example of an anisotropic reflective polarizer is a reflective grid polarizer, a specific example of which is a metal grid reflective polarizer that emits reflected polarized light even in the visible light region by subjecting metal to fine processing (US Patent No. 6288840, etc.), and metal fine particles are mixed into polymers. It is a film added in a matrix and stretched (Japanese Patent Application Laid-Open No. 8-184701).

The thickness of the reflective polarizing plate is not particularly limited, but is, for example, 10 μm or more and 200 μm or less. From the viewpoint of thinning the optical laminate and liquid crystal display device, it is preferably 10 μm or more and 100 μm or less, and more preferably 10 μm. It is less than or equal to 70 ㎛.

The length of the disk reflective polarizing plate 10 in the longitudinal direction is, for example, 10 m or more and 10,000 m or less, and is preferably 100 m or more and 10,000 m or less from the viewpoint of productivity. The disc reflection type polarizing plate 10 may be wound to form a roll, or may be unwound from the roll and used.

The disc reflection type polarizing plate 10 may be subjected to surface activation treatment on its upper surface before being subjected to steps (a1) and (a2). This surface activation treatment makes it difficult for the polarizing film and the retardation film to peel off after they are bonded together.

The surface activation treatment may be a surface hydrophilization treatment, and may be a dry treatment or a wet treatment. Dry treatments include, for example, discharge treatments such as corona treatment, plasma treatment, and glow discharge treatment; flame treatment; ozone treatment; UV ozone treatment; Treatment with ultraviolet rays, ionizing active lines such as electron beam treatment, etc. can be mentioned. Examples of wet treatment include, for example, ultrasonic treatment using a solvent such as water or acetone, alkaline treatment, anchor coat treatment, etc. These treatments may be performed individually or in combination of two or more.

[Polarizing film]

The polarizing film (the original first polarizing film and the original second polarizing film) can be produced from an optically anisotropic layer containing a polymer of a polymerizable liquid crystal compound containing a dichroic dye. With this configuration, the color can be arbitrarily controlled, the thickness can be significantly reduced, and there is no stretching relaxation due to heat, so it has non-contraction properties, making it suitable for use in an image display device.

A polarizing film is formed by applying a composition for forming a polarizing film, if necessary, on an alignment film formed on a substrate, and aligning the dichroic dye contained in the composition for forming a polarizing film. The polarizing film is preferably a film whose thickness is 0.1 μm or more and 5 μm or less, more preferably 0.3 μm or more and 4 μm or less, and even more preferably 0.5 μm or more and 3 μm or less. If the film thickness is thinner than this range, the necessary light absorption may not be obtained. Additionally, if the film thickness is thicker than this range, the alignment control force of the alignment film decreases, and alignment defects tend to occur. Additionally, the composition for forming a polarizing film may further include a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, and an adhesion improver.

The optically anisotropic layer in which the dichroic dye and the polymerizable liquid crystal compound are aligned horizontally with respect to the substrate surface has a ratio of the absorbance A1(λ) in the alignment direction to light with a wavelength λ nm and the absorbance A2(λ) in the vertical direction within the alignment plane ( It is preferable that the two-color ratio is 7 or more, more preferably 20 or more, and even more preferably 40 or more. The higher this value, the better the absorption selectivity of the polarizer. It may vary depending on the type of dichroic dye, but in the case of a liquid crystal cured film cured in a nematic liquid crystalline state, it is about 5 to 10.

By mixing two or more types of dichroic dyes with different absorption wavelengths, a polarizing film of various colors can be produced, and a polarizing film can be created with absorption in the entire visible light range. By using a polarizing film having such absorption characteristics, it can be deployed for various purposes.

<Polarizing film; Polymerizable liquid crystal compounds>

A polymerizable liquid crystal compound is a compound that has a polymerizable group and has liquid crystallinity (hereinafter also referred to as polymerizable liquid crystal). A polymerizable group means a group involved in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in the polymerization reaction by active radicals or acids generated from a photopolymerization initiator described later. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, etc. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and methacryloyloxy group or acryloyloxy group is more preferable. Liquid crystallinity may be either thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferable when mixing with the dichroic dye described later. The polymerizable liquid crystal compound may be a monomer or a polymer obtained by polymerizing a dimer or more.

When the polymerizable liquid crystal compound is a thermotropic liquid crystal, it may be a thermotropic liquid crystal compound showing a nematic liquid crystalline phase, or a thermotropic liquid crystal compound showing a smectic liquid crystalline phase may be used. From the viewpoint of being able to exhibit high dichroism, it is preferable that the liquid crystal state exhibited by the polymerizable liquid crystal compound is a smectic phase, and a high-order smectic phase is more preferable from the viewpoint of improving performance. Among them, Smectic B award, Smectic D award, Smectic E award, Smectic F award, Smectic G award, Smectic H award, Smectic I award, Smectic J award, Smectic K award or Smectic L award. A higher-order Smectic liquid crystal compound that forms a Smectic phase is more preferable, and a higher-order Smectic liquid crystal compound that forms a Smectic B phase, Smectic F phase, or Smectic I phase is more preferable. If the liquid crystal phase formed by the polymerizable liquid crystal is one of these high-order smectic phases, a polarizing film with higher polarization performance can be manufactured. In addition, such a polarizing film with high polarization performance produces a Bragg peak derived from a higher-order structure such as a hexatic phase or a crystal phase in an X-ray diffraction measurement. This Bragg peak is a peak derived from the periodic structure of molecular orientation, and a film with a periodic interval of 3 to 6 Å can be obtained. In the polarizing film of the present invention, it is preferable that the polymerizable liquid crystal contains a polymer of the polymerizable liquid crystal oriented in a smectic phase state from the viewpoint of achieving higher polarization characteristics.

As a polymerizable liquid crystal compound, one type may be used individually, and two or more types may be used in combination. The polymerizable liquid crystal composition containing other compounds described later may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound as long as the effect of the present invention is not impaired, but from the viewpoint of obtaining a polarizing film with a high degree of orientation order. , the ratio of the polymerizable liquid crystal compound to the total mass of all polymerizable liquid crystal compounds contained in the polymerizable liquid crystal composition is preferably 51% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass. It is more than mass%.

The content of the polymerizable liquid crystal compound in the composition for forming a polarizing film of the present invention is preferably 40 to 99.9 mass%, more preferably 60 to 99 mass%, and even more preferably, based on the solid content of the polymerizable liquid crystal composition. Typically, it is 70 to 99% by mass. When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to increase. In addition, in this specification, solid content refers to the total amount of components excluding the solvent in the polymerizable liquid crystal composition.

<Polarizing film; Dichromatic pigment>

A dichroic dye refers to a dye whose absorbance in the major axis direction of the molecule is different from that in the minor axis direction. The dichroic dye preferably has the characteristic of absorbing visible light, and more preferably has a maximum absorption wavelength (λMAX) in the range of 380 to 680 nm. Examples of such dichroic dyes include acridine dye, oxazine dye, cyanine dye, naphthalene dye, azo dye, and anthraquinone dye, but among them, azo dye is preferable. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbenazo dyes, and bisazo dyes and trisazo dyes are preferred. The dichroic dyes may be used alone or in combination, but in order to obtain absorption in the entire visible light range, it is preferable to combine two or more types of dichroic dyes, and it is more preferable to combine three or more types of dichroic dyes.

Examples of the azo dye include a compound represented by formula (I) (hereinafter sometimes referred to as “compound (I)”).

T ¹ -A ¹ (-N=NA ² ) _p -N=NA ³ -T ² (I)

[In Formula (I), A ¹ , A ² , and A ³ are each independently a 1,4-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a 1,4-diyl group which may have a substituent. It represents a benzoic acid phenyl ester group, a 4,4'-stilbenylene group which may have a substituent, or a divalent heterocyclic group which may have a substituent, and T ¹ and T ² are electron-withdrawing groups or electron-emitting groups, and are substantially It has a position of 180°. p represents an integer from 0 to 4. When p is 2 or more, each A ² may be the same or different. In the range where absorption is visible in the visible region, the -N=N- bond may be substituted with a -C=C-, -COO-, -NHCO-, or -N=CH- bond.]

The content of the dichroic dye (total amount when multiple types are included) is usually 1 to 60 parts by mass, preferably 1 to 40 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound from the viewpoint of obtaining good light absorption characteristics. Parts by mass, more preferably 1 to 20 parts by mass. If the content of the dichroic dye is less than this range, light absorption becomes insufficient and sufficient polarization performance cannot be obtained, and if the content of the dichroic dye is more than this range, the alignment of the liquid crystal molecules may be impaired.

[Phase shield]

The retardation film has at least one layer of liquid crystal retardation layer.

<Liquid crystal phase contrast layer>

In this specification, horizontal alignment is defined as when the optical axis of the polymerizable liquid crystal is aligned horizontally with respect to the substrate plane, and vertical alignment is defined as when the optical axis of the polymerizable liquid crystal is aligned perpendicular to the substrate plane. The optical axis refers to the direction in which a cross-section cut in a direction perpendicular to the optical axis becomes a circle in the refractive index ellipsoid formed by the orientation of the polymerizable liquid crystal, that is, the direction in which the refractive indices in all three directions become the same. That is, the optical axis is an axis called the slow axis or fast axis, and is usually the slow axis.

Examples of polymerizable liquid crystals include rod-shaped polymerizable liquid crystals and disk-shaped polymerizable liquid crystals. When the rod-shaped polymerizable liquid crystal is horizontally or vertically aligned with respect to the substrate, the optical axis of the polymerizable liquid crystal coincides with the long axis direction of the polymerizable liquid crystal. When the disc-shaped polymerizable liquid crystal is oriented, the optical axis of the polymerizable liquid crystal exists in a direction perpendicular to the disc surface of the polymerizable liquid crystal.

In order for the layer formed by polymerizing the polymerizable liquid crystal to exhibit an in-plane retardation, the polymerizable liquid crystal just needs to be oriented in an appropriate direction. When the polymerizable liquid crystal is rod-shaped, in-plane phase difference is expressed by aligning the optical axis of the polymerizable liquid crystal horizontally with respect to the substrate plane. In this case, the optical axis direction and the slow axis direction coincide. When the polymerizable liquid crystal is disk-shaped, in-plane phase difference is expressed by aligning the optical axis of the polymerizable liquid crystal horizontally with respect to the substrate plane. In this case, the optical axis and the slow axis are orthogonal. The alignment state of the polymerizable liquid crystal can be adjusted by combining an alignment film and the polymerizable liquid crystal.

The in-plane retardation value of the liquid crystal retardation layer can be adjusted by the thickness of the retardation layer. Since the in-plane retardation value is determined by equation (11), Δn(λ) and the film thickness d can be adjusted to obtain the desired in-plane retardation value (Re(λ)).

Re(λ)=d×Δn(λ) (11)

In the formula, Re(λ) represents the in-plane retardation value at the wavelength λ nm, d represents the film thickness, and Δn(λ) represents the birefringence at the wavelength λ nm.

The birefringence Δn(λ) can be obtained by measuring the in-plane retardation value and dividing it by the thickness of the retardation layer. In a specific measurement method, the actual properties of the retardation layer can be measured by measuring a film formed on a substrate that has no in-plane retardation in the substrate itself, such as a glass substrate.

In this specification, the refractive indices in the three directions of the refractive index ellipsoid formed by the orientation of the polymerizable liquid crystal or stretching of the film are expressed as nx, ny, and nz. nx represents the main refractive index in the direction parallel to the film plane in the refractive index ellipsoid formed by the liquid crystal retardation layer. ny represents the refractive index in the direction parallel to the film plane and orthogonal to the direction of nx in the refractive index ellipsoid formed by the retardation layer. nz represents the refractive index in the direction perpendicular to the film plane in the refractive index ellipsoid formed by the retardation layer.

When the optical axis of the rod-shaped polymerizable liquid crystal is oriented horizontally with respect to the substrate plane, the refractive index relationship of the resulting retardation layer is nx>ny≒nz (positive A plate), and the nx direction axis and the ground plane in the refractive index ellipsoid are The axes coincide.

Additionally, when the optical axis of the disc-shaped polymerizable liquid crystal is oriented horizontally with respect to the substrate plane, the refractive index relationship of the resulting retardation layer is nx<ny≒nz (negative A plate), and the axis in the ny direction in the refractive index ellipsoid is The ground axes coincide.

In order for the layer formed by polymerizing the polymerizable liquid crystal to exhibit a phase difference in the thickness direction, the polymerizable liquid crystal can be oriented in an appropriate direction. In this specification, expressing a phase difference in the thickness direction is defined as showing a characteristic in which Rth (phase difference value in the thickness direction) becomes negative in equation (20). Rth can be calculated from the phase difference value (R ₄₀ ) and the in-plane phase difference value (Re) measured by tilting the in-plane fast axis by 40 degrees using the in-plane fast axis as the inclination axis. That is, Rth determines nx, ny, and nz from Re, R ₄₀ , d (thickness of the retardation layer), and n0 (average refractive index of the retardation layer) using the following equations (21) to (23), and adds them to the equation ( It can be calculated by substituting into 20).

Rth=[(nx+ny)/2-nz]×d (20)

Re=(nx-ny)×d (21)

R ₄₀ =(nx-ny')×d/cos(ϕ) (22)

(nx+ny+nz)/3=n0 (23)

here,

ϕ=sin ^-1 [sin(40°)/n0]

ny'=ny×nz/〔ny ² ×sin ² (ϕ)+nz ² ×cos ² (ϕ)] ^1/2

Additionally, nx, ny and nz have the same definitions as described above.

When the polymerizable liquid crystal is rod-shaped, a phase difference in the thickness direction is expressed by aligning the optical axis of the polymerizable liquid crystal perpendicularly to the plane of the substrate. When the polymerizable liquid crystal is disk-shaped, a phase difference in the thickness direction is expressed by aligning the optical axis of the polymerizable liquid crystal horizontally with respect to the substrate plane. In the case of disc-shaped polymerizable liquid crystals, since the optical axis of the polymerizable liquid crystal is parallel to the substrate plane, when Re is determined, the thickness is fixed, so Rth is determined uniquely, but in the case of rod-shaped polymerizable liquid crystals, Since the optical axis of the polymerizable liquid crystal is perpendicular to the substrate plane, Rth can be adjusted without changing Re by adjusting the thickness of the retardation layer.

When the optical axis of the rod-shaped polymerizable liquid crystal is oriented perpendicular to the substrate plane, the refractive index relationship of the resulting retardation layer is nx≒ny<nz (positive C plate), and the axis in the nz direction in the refractive index ellipsoid and the ground The axis directions match.

Additionally, when the optical axis of the disc-shaped polymerizable liquid crystal is oriented parallel to the substrate plane, the refractive index relationship of the resulting phase difference layer becomes nx<ny≒nz (negative A plate), and the axis in the ny direction in the refractive index ellipsoid is The ground axis direction matches.

<Polymerizable liquid crystal>

A polymerizable liquid crystal is a compound that has a polymerizable group and has liquid crystallinity. A polymerizable group means a group involved in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in the polymerization reaction by active radicals or acids generated from a photopolymerization initiator described later. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, etc. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The liquid crystallinity of polymeric liquid crystals may be thermotropic liquid crystals or lyotropic liquid crystals, and if thermotropic liquid crystals are classified by degree of order, they may be nematic liquid crystals or smectic liquid crystals.

Examples of rod-shaped polymerizable liquid crystals include compounds represented by the following formula (A) and compounds containing a group represented by the following formula (X). As a rod-shaped polymerizable liquid crystal, from the viewpoint of developing wavelength dispersion, a liquid crystal having a T-shaped or H-shaped mesogenic structure that is oriented perpendicular to the molecular axis direction and has birefringence is preferable, and stronger dispersion can be obtained. From this viewpoint, a T-shaped liquid crystal is more preferable, and specific examples of the structure of the T-shaped liquid crystal include a compound represented by the following formula (A).

(Compound represented by formula (A))

Equation (A) is as follows. Hereinafter, the compound represented by formula (A) may be referred to as polymerizable liquid crystal (A).

In formula (A), Ar represents a divalent aromatic group that may have a substituent. The divalent aromatic group preferably contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. When there are two or more aromatic groups contained in the divalent group Ar, the two or more aromatic groups may be bonded to each other by a single bond or by a divalent bonding group such as -CO-O- or -O-.

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

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

k and l each independently represent integers from 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, where the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH ₂ - contained in the alkanediyl group is It may be substituted with -O-, -S-, or -COO-, and if it has multiple -O-, -S-, or -COO-, they are not adjacent to each other. 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 a 1,4-phenylenediyl group, which may be substituted with at least one substituent preferably selected from the group consisting of a halogen atom and an alkyl group with 1 to 4 carbon atoms, a halogen atom and an alkyl group with 1 to 4 carbon atoms. It is a 1,4-cyclohexanediyl group which may be substituted with at least one substituent selected from the group consisting of alkyl groups of 4, more preferably a 1,4-phenylenediyl group substituted with a methyl group, or unsubstituted 1,4. -phenylenediyl group or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group or unsubstituted 1,4-trans-cyclohexanediyl group.

In addition, it is preferable that at least one of the plurality of G ¹ and G ² is a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² is a divalent alicyclic hydrocarbon group. It is more desirable.

L ¹ and L ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2 -, -R ^a3 COOR ^a4 -, -R ^a5 OCOR ^a6 -, R ^a7 OC=OOR ^a8 -, -N=N-, -CR ^c =CR ^d - or C≡C-. Here, R ^a1 to R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group or a hydrogen atom having 1 to 4 carbon atoms. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a4-1 - or OCOR ^a6-1 -. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent a single bond, -CH ₂ -, -CH ₂ CH ₂ -. L ¹ and L ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ - or OCO-.

B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 OR ^a10 -, -R ^a11 COOR ^a12 -, -R ^a13 OCOR ^a14 - or -R ^a15 OC(=O)OR ^a16 -. Here, R ^a9 to R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are each independently more preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a12-1 - or OCOR ^a14-1 -. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent a single bond, -CH ₂ -, -CH ₂ CH ₂ -. B ¹ and B ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, -OCO- or -OCOCH ₂ CH ₂ -.

From the viewpoint of developing reverse wavelength dispersion, 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. If k=2 and l=2, it is desirable because it has a symmetrical structure.

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

The polymerizable group represented by P ¹ or P ² includes epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, and oxiranyl group. and oxetanyl group. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable.

Ar preferably has at least one selected from an aromatic hydrocarbon ring that may have a substituent, an aromatic heterocycle that may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and anthracene ring, with a benzene ring and a naphthalene ring being preferred. Examples of the aromatic heterocycle include furan ring, benzofuran ring, pyrrole ring, indole ring, thiophene ring, benzothiophene ring, pyridine ring, pyrazine ring, pyrimidine ring, triazole ring, triazine ring, pyrroline ring, and imidazole ring. , pyrazole ring, thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzooxazole ring, and phenanthroline ring. Among these, those having a thiazole ring, a benzothiazole ring, or a benzofuran ring are preferable, and those having a benzothiazole group are more preferable. Additionally, when Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

In formula (A), the total number N _π of π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, further preferably 14 or more, and especially preferably It is 16 or more. Moreover, it is preferably 30 or less, more preferably 26 or less, and still more preferably 24 or less.

Suitable examples of the aromatic group represented by Ar include the following groups.

In formulas (Ar-1) to (Ar-23), * indicates a connecting portion, and Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, an alkyl group with 1 to 12 carbon atoms, a cyano group, Nitro group, alkylsulfinyl group with 1 to 12 carbon atoms, alkylsulfonyl group with 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group with 1 to 12 carbon atoms, alkoxy group with 1 to 6 carbon atoms, alkylthio group with 1 to 12 carbon atoms, carbon number Represents an N-alkylamino group of 1 to 12 carbon atoms, an N,N-dialkylamino group of 2 to 12 carbon atoms, an N-alkylsulfamoyl group of 1 to 12 carbon atoms, or an N,N-dialkylsulfamoyl group of 2 to 12 carbon atoms. .

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

J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.

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

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

Examples of the aromatic hydrocarbon group in Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group and biphenyl group, and phenyl group and naphthyl group are preferred, and a phenyl group is more preferred. As an aromatic heterocyclic group, a group having 4 to 20 carbon atoms containing at least one hetero atom such as a nitrogen atom such as a furyl group, pyrrolyl group, thienyl group, pyridinyl group, thiazolyl group, and benzothiazolyl group, an oxygen atom, and a sulfur atom. Examples of aromatic heterocyclic groups include furyl group, thienyl group, pyridinyl group, thiazolyl group, and benzothiazolyl group.

Y ¹ , Y ² and Y ³ may each independently be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group that may be substituted. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring set. Polycyclic aromatic heterocyclic group refers to a group derived from a condensed polycyclic aromatic heterocyclic group or an aromatic ring set.

Z ⁰ , Z ¹ and Z ² are each independently preferably a hydrogen atom, a halogen atom, an alkyl group with 1 to 12 carbon atoms, a cyano group, a nitro group or an alkoxy group with 1 to 12 carbon atoms, and Z ⁰ is a hydrogen atom and 1 carbon atom. An alkyl group or cyano group of ~12 is more preferable, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

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

Among formulas (Ar-1) to (Ar-23), formulas (Ar-6) and (Ar-7) are preferable from the viewpoint of molecular stability.

In formulas (Ar-16) to (Ar-23), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . Examples of the aromatic heterocyclic group include those mentioned above as aromatic heterocyclic rings that Ar may have, for example, pyrrole ring, imidazole ring, pyrroline ring, pyridine ring, pyrazine ring, pyrimidine ring, indole ring, quinoline ring, and isoquinoline. Rings, purine rings, pyrrolidine rings, etc. can be mentioned. This aromatic heterocyclic group may have a substituent. Additionally, Y ¹ , together with the nitrogen atom to which it is bonded and Z ⁰ , may be the optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group described above. Examples include benzofuran ring, benzothiazole ring, and benzoxazole ring.

(Compound containing a group represented by formula (X))

Equation (X) is as follows. Hereinafter, a compound containing a group represented by formula (X) may be referred to as polymerizable liquid crystal (B).

P11-B11-E11-B12-A11-B13- (X)

[In formula (X), P11 represents a polymerizable group.

A11 represents a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group. The hydrogen atom contained in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, a cyano group, or a nitro group, and The hydrogen atom contained in the alkyl group having to 6 carbon atoms and the alkoxy group having 1 to 6 carbon atoms may be substituted with a fluorine atom.

B11 is -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -CO-NR ¹⁶ -, -NR ¹⁶ -CO-, -CO-, -CS - or represents a single bond. R ¹⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

B12 and B13 are each independently -C≡C-, -CH=CH-, -CH ₂ -CH ₂ -, -O-, -S-, -C(=O)-, -C(=O)- O-, -OC(=O)-, -OC(=O)-O-, -CH=N-, -N=CH-, -N=N-, -C(=O)-NR ¹⁶ -, -NR ¹⁶ -C(=O)-, -OCH ₂ -, -OCF ₂ -, -CH ₂ O-, -CF ₂ O-, -CH=CH-C(=O)-O-, -OC( =O)-CH=CH- or represents a single bond.

E11 represents an alkanediyl group having 1 to 12 carbon atoms, and the hydrogen atom contained in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, and the hydrogen atom contained in the alkoxy group may be substituted with a halogen atom. Additionally, -CH ₂ - constituting the alkanediyl group may be substituted with -O- or -CO-.]

The carbon number of the aromatic hydrocarbon group and the alicyclic hydrocarbon group of A11 is preferably in the range of 3 to 18, more preferably in the range of 5 to 12, and especially preferably in the range of 5 or 6. As A11, cyclohexane-1,4-diyl group and 1,4-phenylene group are preferable.

As E11, a linear alkanediyl group having 1 to 12 carbon atoms is preferable. -CH ₂ - constituting the alkanediyl group may be substituted with -O-.

Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7. -Diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group and dodecane-1,12-diyl group. linear alkanediyl groups having 1 to 12 carbon atoms, such as; -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -, -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ - and -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ - and the like.

As B11, -O-, -S-, -CO-O-, and -O-CO- are preferable, and -CO-O- is especially preferable.

B12 and B13 are each independently -O-, -S-, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -O-C(=O)-O- is preferable, and among these, -O- or -O-C(=O)-O- is more preferable.

As the polymerizable group represented by P11, a radical polymerizable group or a cationic polymerizable group is preferable because it has high polymerization reactivity, especially photopolymerization reactivity, and because it is easy to handle and the production of the liquid crystal compound itself is easy, the polymerizable group is of the following formula ( It is preferable that it is a group represented by formulas P-11) to (P-15).

[In formulas (P-11) to (P-15),

R ¹⁷ to R ²¹ each independently represent an alkyl group having 1 to 6 carbon atoms or a hydrogen atom.]

Specific examples of groups represented by formulas (P-11) to (P-15) include groups represented by the following formulas (P-16) to (P-20).

P11 is preferably a group represented by formulas (P-14) to (P-20), and more preferably a vinyl group, p-stilbene group, epoxy group, or oxetanyl group.

It is more preferable that the group represented by P11-B11- is an acryloyloxy group or a methacryloyloxy group.

Examples of the polymerizable liquid crystal (B) include compounds represented by formula (I), formula (II), formula (III), formula (IV), formula (V), or formula (VI).

P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-B16-E12-B17-P12 (I)

P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-F11 (II)

P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-E12-B17-P12 (III)

P11-B11-E11-B12-A11-B13-A12-B14-A13-F11 (IV)

P11-B11-E11-B12-A11-B13-A12-B14-E12-B17-P12 (V)

P11-B11-E11-B12-A11-B13-A12-F11 (VI)

(During the ceremony,

A12 to A14 are each independently synonymous with A11, B14 to B16 are each independently synonymous with B12, B17 is synonymous with B11, and E12 is synonymous with E11.

F11 is a hydrogen atom, an alkyl group with 1 to 13 carbon atoms, an alkoxy group with 1 to 13 carbon atoms, cyano group, nitro group, trifluoromethyl group, dimethylamino group, hydroxy group, methylol group, formyl group, sulfo group (-SO ₃ H) , represents a carboxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or a halogen atom, and -CH ₂ - constituting the alkyl group and alkoxy group may be substituted with -O-.)

Specific examples of polymerizable liquid crystals (B) include “3.8.6 Network (fully cross-linked)” and “6.5.1 liquid crystals” in the Liquid Crystal Handbook (edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. on October 30, 2000). material b. Among the compounds described in “Polymerizable nematic liquid crystal materials,” compounds having a polymerizable group, JP-A-2010-31223, JP-A-2010-270108, JP-A-2011-6360 and JP-A-2011-207765 and the polymerizable liquid crystal described in Publication No.

Specific examples of the polymerizable liquid crystal (B) include the following formulas (I-1) to (I-4), formulas (II-1) to formula (II-4), and formulas (III-1) to formula (III- 26), compounds represented by formulas (IV-1) to formula (IV-26), formulas (V-1) to formula (V-2), and formulas (VI-1) to formula (VI-6). You can. Moreover, in the following formula, k1 and k2 each independently represent an integer of 2 to 12. These polymerizable liquid crystals (B) are preferable in terms of ease of synthesis or availability.

Examples of disk-shaped polymerizable liquid crystals include compounds containing a group represented by the formula (W) (hereinafter sometimes referred to as polymerizable liquid crystal (C)).

[In formula (W), R ⁴⁰ represents the following formulas (W-1) to (W-5).

X ⁴⁰ and Z ⁴⁰ represent an alkyl group having 1 to 12 carbon atoms, and the hydrogen atom contained in the alkyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, and the hydrogen atom contained in the alkoxy group may be substituted with a halogen atom. Additionally, -CH ₂ - constituting the alkyl group may be substituted with -O- or -CO-.

Specific examples of polymerizable liquid crystals (C) include “6.5.1 Liquid crystal materials b.” in the Liquid Crystal Handbook (edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. on October 30, 2000). Polymerizable nematic liquid crystal material Compound described in Figure 6.21, Japanese Patent Application Laid-Open No. 7-258170, Japanese Patent Application Laid-Open No. 7-30637, Japanese Patent Application Laid-Open No. 7-309807, Japanese Patent Application Laid-Open No. 8-231470 and the polymerizable liquid crystal described in Publication No.

A retardation film having the optical properties represented by equations (1) and (2), a layer having the optical properties represented by equations (4), (6), and (7), and a layer having the optical properties represented by equations (5) and (6) and layers having the optical properties expressed by equation (7) in a specific slow axis relationship.

Re(450)/Re(550)≤1.00 (One)

1.00≤Re(650)/Re(550) (2)

100 nm<Re(550)<160 nm (4)

200 nm<Re(550)<320 nm (5)

Re(450)/Re(550)≥1.00 (6)

1.00≥Re(650)/Re(550) (7)

Examples of the polymerizable liquid crystal having the above specific structure include the polymerizable liquid crystal (A). By orienting the polymerizable liquid crystal (A) so that the optical axis is horizontal with respect to the plane of the substrate, a retardation layer having the optical properties expressed by equations (1) and (2) can be obtained, and further according to the above equation (10) By adjusting the film thickness, it is possible to obtain a retardation layer having a desired in-plane retardation value, such as optical properties expressed by equation (4), for example.

Combining a layer with the optical properties expressed by equations (4), (6), and (7) and a layer with the optical properties represented by equations (5), (6), and (7) with a specific slow axis relationship Methods for doing so include well-known methods. For example, Japanese Patent Application Laid-Open No. 2001-4837, Japanese Patent Application Laid-Open No. 2001-21720, and Japanese Patent Application Laid-Open No. 2000-206331 disclose a retardation film having at least two retardation layers made of a liquid crystal compound. Additionally, the layer having the optical properties expressed by equation (4) is also called a 1/4 wavelength layer, and the layer having the optical properties represented by equation (5) is also called a 1/2 wavelength layer, and equations (6) and equations The optical characteristic indicated by (7) is also called constant wavelength dispersion.

A retardation layer having the optical properties represented by the above formulas (6) and (7) can be obtained by a known method. That is, the retardation layer obtained by a method other than the method of obtaining the retardation layer having the optical properties represented by the above formulas (1) and (2) has the optical properties roughly represented by the formulas (6) and (7).

A suitable form of the retardation film includes a liquid crystal retardation layer (first liquid crystal retardation layer) having optical properties expressed by Equations (5), (6) and (7), and Equations (4), (6) and (7). It is a combination of a liquid crystal retardation layer (second liquid crystal retardation layer) having optical properties indicated by ).

100 nm<Re(550)<160 nm (4)

200 nm<Re(550)<320 nm (5)

Re(450)/Re(550)≥1.00 (6)

1.00≥Re(650)/Re(550) (7)

The first liquid crystal retardation layer is preferably a coating layer formed by polymerizing polymerizable liquid crystal (C). The second liquid crystal retardation layer is preferably a coating layer formed by polymerizing the polymerizable liquid crystal (B).

Each of the first liquid crystal retardation layer and the second liquid crystal retardation layer preferably has a thickness of 3.0 μm or less. The thickness of the liquid crystal retardation layer can be determined by measurement using an interference film thickness meter, a laser microscope, or a stylus film thickness meter.

<Description>

The substrate includes a glass substrate and a film substrate, with a film substrate being preferable. A long roll-shaped film is more preferable because it can be manufactured continuously. Resins constituting the film base include, for example, polyolefins such as polyethylene, polypropylene, and norbornene polymers; Cyclic olefin resin; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid ester; polyacrylic acid ester; Cellulose esters such as triacetylcellulose, diacetylcellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide and polyphenylene oxide; Plastics such as these can be mentioned. Among these, from the viewpoint of transparency when used as an optical film, a film substrate selected from any of triacetylcellulose, cyclic olefin resin, polymethacrylic acid ester, and polyethylene terephthalate is more preferable.

Commercially available cellulose ester substrates include “Fujitag Film” (manufactured by Fujishashin Film Co., Ltd.); Examples include "KC8UX2M", "KC8UY", and "KC4UY" (manufactured by Konica Minolta Opto Co., Ltd.).

Commercially available cyclic olefin resins include "Topas" (registered trademark) (manufactured by Ticona (Germany)), "Aton" (registered trademark) (manufactured by JSR Corporation), and "ZEONOR" (registered trademark). , "ZEONEX" (registered trademark) (manufactured by Nippon Zeon Co., Ltd.), and "Apel" (registered trademark) (manufactured by Mitsui Chemicals Co., Ltd.). This cyclic olefin resin can be formed into a film by known means such as solvent casting or melt extrusion to form a base material. A commercially available cyclic olefin resin base material can also be used. Commercially available cyclic olefin resin substrates include “S-Sina” (registered trademark), “SCA40” (registered trademark) (manufactured by Sekisui Chemicals Co., Ltd.), and “Zeonoa Film” (registered trademark) ( and “Aton Film” (registered trademark) (manufactured by JSR Co., Ltd.).

The thickness of the base material is preferably thin enough to allow practical handling, but if it is too thin, the strength tends to decrease and processability is poor. The thickness of the base material is usually 5 μm to 300 μm, preferably 10 μm to 200 μm, and more preferably 10 to 50 μm. Additionally, a further thinning effect can be obtained by peeling the base material and transferring the polarizing film or retardation film to the reflective polarizing plate.

<Alignment film>

In this specification, the alignment film has an alignment regulating force that aligns the polymerizable liquid crystal compound in a desired direction.

The alignment film facilitates liquid crystal alignment of the polymerizable liquid crystal compound. The state of liquid crystal alignment, such as horizontal alignment, vertical alignment, hybrid alignment, and oblique alignment, varies depending on the properties of the alignment film and the polymerizable liquid crystal compound, and their combination can be arbitrarily selected. For example, if the alignment film is a material that exhibits horizontal alignment as an orientation regulating force, the polymerizable liquid crystal compound can form horizontal alignment or hybrid alignment, and if the alignment film is a material that exhibits vertical alignment, the polymeric liquid crystal compound can form vertical alignment or inclined alignment. can do. Expressions such as horizontal and vertical indicate the optical axis direction of the oriented polymerizable liquid crystal compound when the optically anisotropic layer plane is referenced. For example, vertical alignment means having the optical axis of the polymerizable liquid crystal compound aligned in a direction perpendicular to the plane of the optically anisotropic layer. Perpendicular here means 90°±20° with respect to the plane of the optically anisotropic layer.

The orientation regulating force can be arbitrarily adjusted depending on the surface state or rubbing conditions when the alignment film is formed of an orientation polymer, and can be arbitrarily adjusted according to polarized light irradiation conditions etc. when the alignment film is formed of a photo-alignment polymer. Additionally, liquid crystal orientation can be controlled by selecting physical properties such as surface tension and liquid crystallinity of the polymerizable liquid crystal compound.

The alignment film formed between the substrate and the liquid crystal retardation layer is preferably insoluble in the solvent used when forming the liquid crystal retardation layer on the alignment film and has heat resistance in heat treatment for removing the solvent or aligning the liquid crystal. do. Examples of the orientation film include an orientation film made of an orientation polymer, a photo-alignment film, a groove orientation film, and a stretched film stretched in the orientation direction. When applied to a long roll-type film, the orientation direction can be easily controlled. A photo-alignment layer is preferable in that it exists.

The thickness of the alignment film is usually in the range of 10 nm to 5000 nm, preferably in the range of 10 nm to 1000 nm, and more preferably in the range of 30 to 300 nm.

Orienting polymers used in the rubbing alignment film include polyamides and gelatins having an amide bond in the molecule, polyimide having an imide bond in the molecule and its hydrolyzate, polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, and polyacrylic. Amides, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters can be mentioned. Among them, polyvinyl alcohol is preferable. These orientation polymers may be used individually, or may be used in combination of two or more types.

A method of rubbing includes a method of applying an oriented polymer composition to a base material and annealing it with a rubbing roll wound and rotating with a rubbing cloth, thereby contacting the film of the oriented polymer formed on the surface of the base material.

The photo-alignment layer is made of a polymer, oligomer, or monomer having a photoreactive group. The photo-alignment film obtains an orientation regulation force by irradiating polarized light. A photo-alignment film is more preferable because the direction of the orientation regulating force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

A photoreactive group refers to a group that generates liquid crystal alignment ability by irradiating light. Specifically, it generates a photoreaction that is the origin of the liquid crystal alignment ability, such as the orientation of molecules caused by irradiation of light or an isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction. Among the photoreactive groups, those that cause a dimerization reaction or a photocrosslinking reaction are preferred because they have excellent orientation. The photoreactive group capable of causing the above reaction preferably has an unsaturated bond, especially a double bond, such as a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), and nitrogen. - A group having at least one selected from the group consisting of a nitrogen double bond (N=N bond) and a carbon-oxygen double bond (C=O bond) is more preferable.

Examples of photoreactive groups having a C=C bond include vinyl group, polyene group, stilbene group, stilbazol group, stilbazolium group, chalcone group, and cinnamoyl group. From the viewpoint of ease of control of reactivity and expression of orientation regulation force during photo-alignment, chalcone group and cinnamoyl group are preferable. Examples of photoreactive groups having a C=N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of the photoreactive group having an N=N bond include an azobenzene group, azonaphthalene group, aromatic heterocyclic azo group, bisazo group, and forma residue group, and those having azoxybenzene as the basic structure. Examples of the photoreactive group having a C=O bond include benzophenone group, coumarin group, anthraquinone group, and maleimide group. These groups may have substituents such as an alkyl group, alkoxy group, aryl group, allyloxy group, cyano group, alkoxycarbonyl group, hydroxyl group, sulfonic acid group, and halogenated alkyl group.

To irradiate polarized light, a form may be used in which polarized light is irradiated directly from the film surface, or a form in which polarized light is irradiated from the substrate side and the polarized light is transmitted through the irradiation method may be used. Additionally, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range where the photoreactive group of a polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) with a wavelength in the range of 250 to 400 nm is particularly preferable. Light sources used for the polarization irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and more examples of high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps. desirable. These lamps are preferable because they have a high emission intensity of ultraviolet light with a wavelength of 313 nm. Polarized light can be irradiated by irradiating light from the light source through an appropriate polarizer. For such a polarizer, a polarizing filter, a polarizing prism such as Glenn Thompson or Glenn Taylor, or a wire grid type polarizer can be used.

<Composition for forming a polarizing film, composition for forming a liquid crystal retardation layer>

The composition for forming a polarizing film or the composition for forming a liquid crystal retardation layer (hereinafter also referred to as the composition for forming an optically anisotropic layer) contains reactive additives such as a solvent, leveling agent, polymerization initiator, photosensitizer, polymerization inhibitor, crosslinking agent, and adhesive agent. may further be included, and it is preferable from the viewpoint of processability to include a solvent or a leveling agent.

(solvent)

The composition for forming an optically anisotropic layer may contain a solvent. In general, polymerizable liquid crystal compounds have a high viscosity, so application is facilitated by dissolving them in a solvent as a composition for forming an optically anisotropic layer, and as a result, the formation of an optically anisotropic layer is often facilitated. The solvent is preferably one that can completely dissolve the polymerizable liquid crystal compound, and is also preferably a solvent that is inert to the polymerization reaction of the polymerizable liquid crystal compound.

Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; Ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; Aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; Chlorine-containing solvents such as chloroform and chlorobenzene; and amide-based solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. These solvents may be used individually, or may be used in combination of two or more types.

The content of the solvent is preferably 50 to 98% by mass relative to the total amount of the composition for forming the optically anisotropic layer. In other words, the solid content in the composition for forming an optically anisotropic layer is preferably 2 to 50 mass%, and more preferably 5 to 30 mass%. If the solid content is 50% by mass or less, the viscosity of the composition for forming an optically anisotropic layer is lowered, and the thickness of the optically anisotropic layer becomes approximately uniform, which tends to make it difficult for interference spots to occur in the optically anisotropic layer. Additionally, the content of this solid content can be determined by considering the thickness of the optically anisotropic layer to be manufactured.

(Leveling system)

The composition for forming an optically anisotropic layer may contain a leveling agent. A leveling agent is an additive that has the function of adjusting the fluidity of the composition and making the film obtained by applying the composition more flat. Examples include organic modified silicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents. Among these, a polyacrylate-based leveling agent and a perfluoroalkyl-based leveling agent are preferable in the case of horizontal alignment, and an organic modified silicone-based leveling agent and a perfluoroalkyl-based leveling agent are preferable in the case of vertical alignment.

When the composition for forming an optically anisotropic layer contains a leveling agent, the amount is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. If the content of the leveling agent is within the above range, it is easy to horizontally align the polymerizable liquid crystal compound, and the resulting optically anisotropic layer tends to be smoother. If the content of the leveling agent in the polymerizable liquid crystal compound exceeds the above range, interference spots tend to occur in the resulting optically anisotropic layer. Additionally, the composition for forming an optically anisotropic layer may contain two or more types of leveling agents.

(polymerization initiator)

The composition for forming an optically anisotropic layer may contain a polymerization initiator. A polymerization initiator is a compound that can initiate a polymerization reaction of a polymerizable liquid crystal compound. As a polymerization initiator, a photopolymerization initiator that generates active radicals by the action of light is preferable from the viewpoint of not being dependent on the phase state of the thermotropic liquid crystal.

As the photopolymerization initiator, any known photopolymerization initiator can be used as long as it is a compound capable of initiating the polymerization reaction of the polymerizable liquid crystal compound. Specifically, photopolymerization initiators that can generate active radicals or acids under the action of light may be mentioned, and among these, photopolymerization initiators that generate radicals under the action of light are preferable. Photopolymerization initiators can be used individually or in combination of two or more types.

Known photopolymerization initiators can be used as the photopolymerization initiator. For example, photopolymerization initiators that generate active radicals include self-cleavable benzoin-based compounds, acetophenone-based compounds, hydroxyacetophenone-based compounds, and α-aminoacetope. Non-based compounds, oxime ester-based compounds, acylphosphine oxide-based compounds, azo-based compounds, etc. can be used, and hydrogen-releasing benzophenone-based compounds, alkylphenone-based compounds, benzoin ether-based compounds, benzyl ketal-based compounds, and dibenzo Suberone-based compounds, anthraquinone-based compounds, xanthone-based compounds, thioxanthone-based compounds, halogenoacetophenone-based compounds, dialkoxyacetophenone-based compounds, halogenobisimidazole-based compounds, halogenotriazine-based compounds, Triazine-based compounds and the like can be used. As photopolymerization initiators that generate acid, iodonium salts and sulfonium salts can be used. From the viewpoint of excellent reaction efficiency at low temperatures, self-cleavage type photopolymerization initiators are preferable, and acetophenone-based compounds, hydroxyacetophenone-based compounds, α-aminoacetophenone-based compounds, and oxime ester-based compounds are particularly preferable.

The content of the polymerization initiator in the composition for forming an optically anisotropic layer can be appropriately adjusted depending on the type and amount of the polymerizable liquid crystal compound, but is usually 0.1 to 30 parts by mass, preferably 0.1 to 30 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. is 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass. If the content of the polymerization initiator is within the above range, polymerization can be performed without disturbing the orientation of the polymerizable liquid crystal compound.

(Sensitizer)

The composition for forming an optically anisotropic layer may contain a sensitizer. As a sensitizer, a photosensitizer is preferable. Examples of the sensitizer include xanthone compounds such as xanthone and thioxanthone (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); Anthracene compounds such as anthracene and alkoxy group-containing anthracene (such as dibutoxyanthracene); Phenothiazine, rubrene, etc. can be mentioned.

When the composition for forming an optically anisotropic layer contains a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the composition for forming an optically anisotropic layer can be further promoted. The amount of this sensitizer used is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound.

(antioxidant)

From the viewpoint of stably advancing the polymerization reaction, the composition for forming an optically anisotropic layer may contain an antioxidant. The progress of the polymerization reaction of the polymerizable liquid crystal compound can be controlled by using antioxidants.

The antioxidant may be, for example, a primary antioxidant selected from phenol-based antioxidants, amine-based antioxidants, quinone-based antioxidants, and nitroso-based antioxidants, or a secondary antioxidant selected from phosphorus-based antioxidants and sulfur-based antioxidants. good night.

When the composition for forming an optically anisotropic layer contains an antioxidant, the content of the antioxidant is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. More preferably, it is 0.5 to 8 parts by mass. Antioxidants can be used individually or in combination of two or more types. If the antioxidant content is within the above range, polymerization can be performed without disturbing the orientation of the polymerizable liquid crystal compound.

(Composition for forming optically anisotropic layer; reactive additive)

The composition for forming an optically anisotropic layer may include a reactive additive. As a reactive additive, it is preferable to have a carbon-carbon unsaturated bond, an active hydrogen reactive group, or a thiol group in the molecule. In addition, the "active hydrogen reactive group" herein refers to a group that is reactive toward groups having active hydrogen such as carboxyl group (-COOH), hydroxyl group (-OH), and amino group (-NH ₂ ), and glycidyl group and oxa group. Representative examples include sleepy group, carbodiimide group, aziridine group, imide group, isocyanate group, thioisocyanate group, and maleic anhydride group. The number of reactive groups each reactive additive has is usually 1 to 20, preferably 1 to 10 each.

<Polarizing film, liquid crystal retardation layer>

(protective layer)

The polarizing film or liquid crystal retardation layer (hereinafter also referred to as optical anisotropic layer) may further have a protective layer. When the optically anisotropic layer is adhesively laminated to another film using an adhesive or the like, having a protective layer prevents low molecular weight components such as unreacted polymerizable liquid crystal compounds or dichroic dyes in the optically anisotropic layer from diffusing into other layers. You can.

The protective layer is preferably thin as long as it can prevent low molecular weight components such as unreacted polymerizable liquid crystal compounds or dichroic dyes in the optically anisotropic layer from diffusing into other layers. A preferable film thickness is 0.1 μm or more and 10 μm or less, more preferably 0.1 μm or more and 5 μm or less, and still more preferably 0.1 μm or more and 3 μm or less.

The protective layer is preferably a polymer with a high crosslinking density or a water-soluble polymer with a high hydrophilic interaction. For example, it contains at least one type selected from the group consisting of acrylic resin, epoxy resin, oxetane resin, urethane resin, melamine resin, and polyvinyl alcohol resin. Among these, from the viewpoint of being easy to form with high curability, it is preferable that it contains at least one selected from the group consisting of acrylic resin, epoxy resin, oxetane resin, urethane resin, and melamine resin, and acrylic resin and urethane resin. It is more preferable that it contains at least one type selected from the group consisting of. Additionally, polyvinyl alcohol resin is preferable from the viewpoint of hydrophilicity.

<Method for manufacturing optically anisotropic layer>

The optically anisotropic layer can be manufactured by applying a composition for forming an optically anisotropic layer on a substrate and an alignment layer. In this specification, the width of the original first polarizing film, the width of the original second polarizing film, the width of the first polarizing film, the width of the second polarizing film, the width of the original first retardation film, the width of the original second retardation film, and the width of the first retardation film. , In the case of the width of the second retardation film, this width means the width of the area on which the composition for forming an optically anisotropic layer is applied.

<Application of composition for forming optically anisotropic layer>

Methods for applying the composition for forming an optically anisotropic layer on a substrate or alignment film include extrusion coating, direct gravure coating, reverse gravure coating, CAP coating, slit coating, micro gravure, die coating, inkjet, etc. can be mentioned. In addition, a method of applying using a coater such as a dip coater, bar coater, or spin coater can also be mentioned. Among them, in the case of continuous application in roll to roll format, application methods by micro gravure method, inkjet method, slit coating method, and die coating method are preferable, and the application method is preferred for sheet wafer substrates such as glass. When applying, a spin coating method with high uniformity is preferable. When applying in a roll-to-roll format, a composition for forming an alignment film, etc. may be applied to a substrate to form an alignment film, and the composition for forming an optically anisotropic layer may be continuously applied on the obtained alignment film.

<Drying of composition for forming optically anisotropic layer>

Drying methods for removing the solvent contained in the composition for forming an optically anisotropic layer include, for example, natural drying, ventilation drying, heat drying, reduced pressure drying, and methods combining these. Among these, natural drying or heat drying are preferable. The drying temperature is preferably in the range of 0 to 200°C, more preferably in the range of 20 to 150°C, and even more preferably in the range of 50 to 130°C. The drying time is preferably 10 seconds to 10 minutes, more preferably 30 seconds to 5 minutes. The composition for forming a photo-alignment film and the alignment polymer composition can also be dried in the same manner.

<Polymerization of polymerizable liquid crystal compound>

Photopolymerization is preferred as a method for polymerizing the polymerizable liquid crystal compound. Photopolymerization is performed by irradiating active energy rays to a laminate on which a composition for forming an optically anisotropic layer containing a polymerizable liquid crystal compound is applied on a substrate or an alignment film. The active energy ray to be irradiated depends on the type of polymerizable liquid crystal compound contained in the dry film (particularly, the type of photopolymerizable functional group that the polymerizable liquid crystal compound has) and, in the case where it contains a photopolymerization initiator, the type and amount of the photopolymerization initiator. are selected appropriately. Specifically, 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 can be mentioned. Among them, ultraviolet light is preferred because it is easy to control the progress of the polymerization reaction and because it is possible to use a photopolymerization device that is widely used in the industry, and the polymerizable liquid crystal compound can be photopolymerized by ultraviolet light. It is advisable to choose a type.

Light sources of the active energy rays include, for example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium interference lamps, excimer lasers, and wavelength ranges of 380 to 440 nm. Examples include LED light sources that emit light, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

The ultraviolet irradiation intensity is usually 10 mW/cm ² to 3,000 mW/cm ² . The ultraviolet irradiation intensity is preferably an intensity in the wavelength range effective for activation of the cationic polymerization initiator or radical polymerization initiator. The time for irradiating light is usually 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and still more preferably 10 seconds to 1 minute. When irradiated once or several times with this ultraviolet irradiation intensity, the accumulated light amount is 10 mJ/cm ² to 3,000 mJ/cm ² , preferably 50 mJ/cm ² to 2,000 mJ/cm ² , more preferably 100 mJ. /cm ² ∼1,000 mJ/cm ² . When the accumulated light amount is below this range, curing of the polymerizable liquid crystal compound becomes insufficient and good transferability may not be obtained. Conversely, when the accumulated light amount is above this range, the optical film containing the optically anisotropic layer may be colored.

[Adhesive layer]

The point adhesive layer can be used to bond a reflective polarizing plate and a polarizing film or retardation film. The adhesive layer may be an adhesive layer or an adhesive layer. The adhesive layer is a layer formed from an adhesive composition, and the adhesive layer is a layer formed from an adhesive composition.

Examples of the adhesive composition include water-based adhesive compositions and curable adhesive compositions that are cured by heating or irradiation of active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Examples of the water-based adhesive composition include those in which polyvinyl alcohol-based resin or urethane resin as the main component is dissolved in water, and those in which polyvinyl alcohol-based resin or urethane resin as the main component are dispersed in water.

The curable adhesive composition is preferably an active energy ray-curable adhesive composition that contains a curable (polymerizable) compound as a main component and is cured by irradiation of active energy rays. Examples of the active energy ray-curable adhesive composition include a cationically polymerizable adhesive composition containing a cationically polymerizable compound as a curable compound, a radically polymerizable adhesive composition containing a radically polymerizable compound as a curable compound, and a radically polymerized adhesive composition with a cationically polymerizable compound as a curable compound. and a hybrid adhesive composition containing both chemical compounds.

As the adhesive composition, adhesive compositions with excellent optical transparency can be used without particular restrictions. For example, adhesive compositions having base polymers such as acrylic resin, urethane resin, silicone resin, and polyvinyl ether resin can be used. Additionally, an active energy ray-curable adhesive composition, a heat-curable adhesive composition, etc. may be used.

The thickness of the adhesive layer is usually 0.1 to 30 μm, preferably 3 to 30 μm, and more preferably 5 to 25 μm.

The thickness of the adhesive layer formed from the water-based adhesive composition may be, for example, 5 μm or less, preferably 1 μm or less, more preferably 0.5 μm or less, may be 0.01 μm or more, and is preferably 0.05 μm or more.

The thickness of the adhesive layer formed from the active energy ray-curable adhesive composition may be, for example, 10 ㎛ or less, preferably 5 ㎛ or less, more preferably 3 ㎛ or less, may be 0.1 ㎛ or more, and is preferably 0.5 ㎛ or more, It is more preferable that it is 1 μm or more.

10: reflective polarizer, disk reflective polarizer, 11: first reflective polarizer, 12: second reflective polarizer, 20: raw film, 50: disk first polarizer, 51, 52: first polarizer, 60 : Disk second polarizing film, 61, 62: Second polarizing film, 71, 72, 81, 82, 91, 92: Optical laminate, 80: Retardation film, R: Reflection axis, E: Absorption axis, F: Ground axis.

Claims (8)

(a1) A long disk optical film having an upper surface and a lower surface, wherein the angle α ₁ [°] of the optical axis with respect to the width direction when viewed from the top is -1° to 1° in the center part in the width direction, and the center part in the width direction is The optical film that changes toward both ends in the width direction is cut to be divided into plural parts in the width direction, and the average value α _{1 m} of the angle α ₁ [°] formed with respect to the width direction of the optical axis when viewed from the top is positive, and a first optical film , a process of obtaining a second optical film in which the average value α _2m of the angle α ₂ [°] formed with respect to the width direction of the optical axis when viewed from the top is negative,
(c11) a process of preparing a long disk first polarizing film and a disk second polarizing film having an upper surface and a lower surface,
(c12) A process of cutting the original first polarizing film into two pieces in the width direction to obtain two sheets of the first polarizing film,
(c13) A process of cutting the original second polarizing film into two pieces in the width direction to obtain two sheets of the second polarizing film,
(d1) A process of obtaining a laminate by bonding the first optical film and the first polarizing film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction coincide with each other,
(e1) A process of obtaining a laminate by bonding the second optical film and the second polarizing film with their upper surfaces facing each other so that their width directions and longitudinal directions match each other.
With
The disk first polarizing film and the disk second polarizing film contain a polymer of a polymerizable liquid crystalline compound,
In the above step (c11), the angle β ₁ [°] formed by the first circular polarizing film with respect to the width direction of the absorption axis when viewed from the top satisfies the following equation (i), and the second circular polarizing film satisfies the equation (i) when viewed from the upper plane. A method of manufacturing a laminate wherein the angle β ₂ [°] formed with respect to the width direction of the absorption axis satisfies the following formula (ii).
β ₁ =-(A ₁ /2)(1.0±0.3) (i)
β ₂ =-(A ₂ /2)(1.0±0.3) (ii)
[In the above formula (i), A ₁ represents the absolute value of the angle α _1a , and in the above formula (ii), A ₂ represents the absolute value of the angle α _2a .] The method of claim 1, wherein when the width of the first optical film is B ₁ [mm], the respective widths of the second optical film, the first polarizing film, and the second polarizing film are in the range of 0.7B ₁ to 1.3B ₁ Method for manufacturing endogenous laminates. The method for manufacturing a laminate according to claim 1 or 2, wherein the bonding in the step (d1) and the step (e1) involves interposing an adhesive layer between opposing upper surfaces. The process according to claim 1 or 2, wherein, with respect to the first optical film and the second optical film, the angle α ₁ and the angle α ₂ with the maximum absolute value are determined, and the angles are set to angle α _1a and angle α _2a , respectively ( With b1),
In the step (b1), the angle α _1a is determined to be 5° or less, and the angle α _2a is determined to be -5° or more. (a2) A long disk optical film having an upper surface and a lower surface, wherein the angle α ₁ [°] of the optical axis with respect to the width direction when viewed from the top is -1° to 1° in the center part in the width direction, and the center part in the width direction is The optical film that changes toward both ends in the width direction is cut to be divided into plural pieces in the width direction, and the average value α _{1 m} of the angle α ₁ [°] formed with respect to the width direction of the optical axis when viewed from the top is positive, and a first optical film , a process of obtaining a second optical film in which the average value α _2m of the angle α ₂ [°] formed with respect to the width direction of the optical axis when viewed from the image plane is negative,
(c21) a process of preparing a long disk first retardation film and a disk second retardation film having an upper surface and a lower surface,
(c22) A process of cutting the original first retardation film into two pieces in the width direction to obtain two sheets of the first retardation film,
(c23) A process of cutting the original second retardation film into two pieces in the width direction to obtain two sheets of the second retardation film,
(d2) A process of obtaining a laminate by bonding the first optical film and the first retardation film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction coincide with each other,
(e2) A process of obtaining a laminate by bonding the second optical film and the second retardation film with their upper surfaces facing each other so that the width direction and the longitudinal forward direction match each other.
With
In the above step (c21), the angle γ ₁ [°] formed by the disk first retardation film with respect to the width direction of the slow axis when viewed from the top satisfies the following equation (iii) or (iv), and the disk second phase difference film satisfies the formula (iii) or (iv) below. A method of manufacturing a laminate wherein the angle γ ₂ [°] formed by the film with respect to the width direction of the slow axis when viewed from the top satisfies the following equation (v) or (vi).
γ ₁ =-(A ₁ /2)(1.0±0.3)+45 (iii)
γ ₁ =-(A ₁ /2)(1.0±0.3)-45 (iv)
γ ₂ =-(A ₂ /2)(1.0±0.3)+45 (v)
γ ₂ =-(A ₂ /2)(1.0±0.3)-45 (vi)
[In the above formulas (iii) and (iv), A ₁ represents the absolute value of the angle α _1a , and in the above formulas (v) and (vi), A ₂ represents the absolute value of the angle α _2a .] The method of claim 5, wherein when the width of the first optical film is B ₁ [mm], each width of the second optical film, the first retardation film, and the second retardation film is 0.7B ₁ or more and 1.3B ₁ or less. Method for manufacturing a laminate within the scope. The method for producing a laminate according to claim 5 or 6, wherein the bonding in the step (d2) and the step (e2) involves interposing an adhesive layer between opposing upper surfaces. The process according to claim 5 or 6, wherein, with respect to the first optical film and the second optical film, the angle α ₁ and the angle α ₂ having the maximum absolute value are determined, and the angle α _1a and the angle α _2a are respectively set ( With b2),
In the step (b2), the angle α _1a is determined to be 5° or less, and the angle α _2a is determined to be -5° or more.