阅读说明：本技术 层叠体 (Laminated body ) 是由 西村直弥 三户部史岳 藤木优壮 武田淳 于 2019-01-30 设计创作，主要内容包括：本发明的课题在于提供一种反射光的变色减少的层叠体。所述层叠体依次具有：光学膜,具有使用包含本发明的二色性物质的组合物形成的光吸收各向异性膜且透射率大于50％；λ/4板；及金属电极,在将光学膜在波长λ下的偏振度(％)设为P(λ)且将金属电极在波长λ下的反射率(％)设为R(λ)时,在波长450nm、550nm及650nm下的R/P的最小值相对于R/P的最大值的比例大于85％。(The present invention addresses the problem of providing a laminate that reduces discoloration of reflected light. The laminate comprises, in order: an optical film having a light absorption anisotropic film formed using a composition containing the dichroic substance of the present invention and having a transmittance of more than 50%; a lambda/4 plate; and a metal electrode, wherein when the polarization degree (%) of the optical film at the wavelength lambda is P (lambda) and the reflectance (%) of the metal electrode at the wavelength lambda is R (lambda), the ratio of the minimum value of R/P at the wavelengths of 450nm, 550nm and 650nm to the maximum value of R/P is more than 85%.)

1. A laminate having, in order:

an optical film having a light absorption anisotropic film formed using a composition containing a dichroic substance, and having a transmittance of more than 50% in a wavelength range of 400 to 700 nm;

a lambda/4 plate; and

a metal electrode,

the optical film satisfies the following formula (A) when the polarization degree (%) of the optical film at a wavelength lambda is P (lambda) and the reflectance (%) of the metal electrode at the wavelength lambda is R (lambda),

100 x [ min { R (450)/P (450), R (550)/P (550), R (650)/P (650) }/max { R (450)/P (450), R (550)/P (550), R (650)/P (650) } > 85% formula (A)

Wherein, in the formula (a), min { R (450)/P (450), R (550)/P (550), R (650)/P (650) } and max { R (450)/P (450), R (550)/P (550), R (650)/P (650) } respectively represent the minimum value and the maximum value among R (450)/P (450), R (550)/P (550), and R (650)/P (650).

2. The laminate according to claim 1, wherein,

in the formula (A), R (550)/P (550) does not satisfy min { R (450)/P (450), R (550)/P (550), R (650)/P (650) }, and also does not satisfy max { R (450)/P (450), R (550)/P (550), R (650)/P (650) }.

3. The laminate according to claim 1 or 2,

in the formula (A), the compound represented by the formula (A),

r (450)/P (450) satisfies min { R (450)/P (450), R (550)/P (550), R (650)/P (650) }, and

r (650)/P (650) corresponds to max { R (450)/P (450), R (550)/P (550), R (650)/P (650) }.

4. The laminate according to any one of claims 1 to 3,

the optical film has the maximum value of the polarization degree in 555-700 nm and meets the condition that P (450) < P (550).

5. The laminate according to any one of claims 1 to 4,

the dichroic substance includes a compound represented by the following formula (1),

in the formula (1), A¹、A²And A³Each independently represents a 2-valent aromatic group which may have a substituent,

in the formula (1), L¹And L²Each independently represents a substituent group, and each independently represents a substituent group,

in the formula (1), m represents an integer of 1-4When m is an integer of 2 to 4, a plurality of A²May be the same as or different from each other.

6. The laminate according to any one of claims 1 to 5,

the dichroic substance includes a compound represented by the following formula (2),

in the formula (2), A⁴Represents an aromatic group having a valence of 2 which may have a substituent,

in the formula (2), L³And L⁴Each independently represents a substituent group, and each independently represents a substituent group,

in the formula (2), E represents any one atom of a nitrogen atom, an oxygen atom and a sulfur atom,

in the formula (2), R¹Represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent or an alkoxy group which may have a substituent,

in the formula (2), R²Represents a hydrogen atom or an alkyl group which may have a substituent,

in the formula (2), R³Represents a hydrogen atom or a substituent group,

in the formula (2), n represents 0 or 1, wherein n is 1 when E is a nitrogen atom, and n is 0 when E is an oxygen atom or a sulfur atom.

7. The laminate according to any one of claims 1 to 6,

the content of the dichroic material is 25% by mass or less with respect to the total mass of the total solid components of the composition.

8. The laminate according to any one of claims 1 to 7,

the λ/4 plate shows reverse wavelength dispersion.

9. The laminate according to any one of claims 1 to 8,

the metal electrode is an electrode sandwiching an organic light emitting layer of the organic electroluminescent display panel.

10. The laminate according to any one of claims 1 to 8,

the metal electrode is an electrode provided in the touch sensor.

Technical Field

The present invention relates to a laminate.

Background

Conventionally, in a display device represented by an Organic Light Emitting Diode (OLED), a circular polarizing plate in which a linear polarizing plate and a λ/4 plate are laminated has been used in order to prevent reflection of external light.

Iodine, which is a dichroic substance, is widely used for polarizers in such linearly polarizing plates (patent document 1).

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2006 and 317747

Disclosure of Invention

Technical problem to be solved by the invention

As described above, the circularly polarizing plate in which the linear polarizing plate and the λ/4 plate are laminated is used to prevent reflection of an organic electroluminescence display panel (hereinafter, also referred to as a "display panel") having a metal electrode and an organic light emitting layer.

On the other hand, in order to make patterns (images, characters, and the like) displayed on the display panel clear, it is required that light generated from the organic light emitting layer easily transmits to the viewing side of the display panel. As a measure against this problem, there is a method of using an optical film having high transmittance and including a light-absorbing anisotropic film, instead of a conventional linearly polarizing plate.

However, the present inventors have obtained the following findings: when the optical film as described above, which is excellent in transmittance for light generated from the light-emitting layer, is used, a new problem arises. That is, a part of the light irradiated from the viewing side of the optical film is incident on the metal electrode of the display panel. Further, a part of the reflected light of the light incident on the metal electrode transmits through the optical film. In this case, there is a problem that light transmitted through the optical film (reflected light from the metal electrode) appears to be discolored.

Accordingly, an object of the present invention is to provide a laminate with reduced discoloration of reflected light.

Means for solving the technical problem

As a result of intensive studies on the above-described problems, the present inventors have found that, in a laminate in which an optical film having a high transmittance and a light-absorbing anisotropic film formed using a composition containing a dichroic material, a λ/4 plate, and a metal electrode are laminated, when the relationship between the degree of polarization of the optical film at a specific wavelength and the reflectance of the metal electrode at a specific wavelength satisfies a predetermined relationship, discoloration of reflected light can be reduced, and have reached the present invention.

That is, the present inventors have found that the above problems can be solved by the following configuration.

[1]

A laminate having, in order:

an optical film having a light absorption anisotropic film formed using a composition containing a dichroic substance and having a transmittance of more than 50% in a wavelength range of 400 to 700 nm;

a lambda/4 plate; and

a metal electrode,

when the degree of polarization (%) of the optical film at a wavelength λ is P (λ) and the reflectance (%) of the metal electrode at the wavelength λ is R (λ), the following formula (a) is satisfied.

100 x [ min { R (450)/P (450), R (550)/P (550), R (650)/P (650) }/max { R (450)/P (450), R (550)/P (550), R (650)/P (650) } > 85% formula (A)

Wherein, in the formula (a), min { R (450)/P (450), R (550)/P (550), R (650)/P (650) } and max { R (450)/P (450), R (550)/P (550), R (650)/P (650) } respectively represent the minimum value and the maximum value among R (450)/P (450), R (550)/P (550), and R (650)/P (650).

[2]

The laminate according to [1], wherein in the formula (A), R (550)/P (550) does not satisfy min { R (450)/P (450), R (550)/P (550), R (650)/P (650) }, and does not satisfy max { R (450)/P (450), R (550)/P (550), R (650)/P (650) }.

[3]

The laminate according to [1] or [2], wherein,

in the above-mentioned formula (A),

r (450)/P (450) satisfies min { R (450)/P (450), R (550)/P (550), R (650)/P (650) }, and

r (650)/P (650) corresponds to max { R (450)/P (450), R (550)/P (550), R (650)/P (650) }.

[4]

The laminate according to any one of [1] to [3], wherein the optical film has a maximum value of a polarization degree in a range of 555 to 700nm and satisfies P (450) < P (550).

[5]

The laminate according to any one of [1] to [4], wherein the dichroic substance contains a compound represented by formula (1) described later.

In the formula (1) described later, A¹、A²And A³Each independently represents an aromatic group having a valence of 2 which may have a substituent.

In the formula (1) described later, L¹And L²Each independently represents a substituent.

In the formula (1), m represents an integer of 1 to 4, and when m is an integer of 2 to 4, a plurality of A²May be the same as or different from each other.

[6]

The laminate according to any one of [1] to [5], wherein the dichroic material contains a compound represented by formula (2) described later.

In the formula (2) described later, A⁴Represents an aromatic group having a valence of 2 which may have a substituent.

In the formula (2) described later, L³And L⁴Each independently represents a substituent.

In formula (2) described later, E represents any one atom of a nitrogen atom, an oxygen atom and a sulfur atom.

In the formula (2) described later, R¹Represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent.

In the formula (2) described later, R²Represents a hydrogen atom or an alkyl group which may have a substituent.

In the formula (2) described later, R³Represents a hydrogen atom or a substituent.

In the formula (2) described later, n represents 0 or 1. Wherein n is 1 when E is a nitrogen atom, and n is 0 when E is an oxygen atom or a sulfur atom.

[7]

The laminate according to any one of [1] to [6], wherein a content of the dichroic substance is 25% by mass or less with respect to a total mass of total solid components of the composition.

[8]

The laminate according to any one of [1] to [7], wherein the λ/4 plate exhibits inverse wavelength dispersibility.

[9]

The laminate according to any one of [1] to [8], wherein the metal electrode is an electrode sandwiching an organic light-emitting layer of an organic electroluminescent display panel.

[10]

The laminate according to any one of [1] to [8], wherein the metal electrode is an electrode provided in a touch sensor.

Effects of the invention

As described below, according to the present invention, a laminate with reduced discoloration of reflected light can be provided.

Drawings

Fig. 1 is a schematic side view showing an embodiment of a laminate according to the present invention.

Fig. 2 is a graph showing a reflection spectrum of a general metal.

Fig. 3 is a graph showing the degree of polarization of the optical film for each wavelength.

Fig. 4 is a graph showing a value obtained by dividing the reflectance of metal by the degree of polarization of the optical film for each wavelength.

Detailed Description

The present invention will be described in detail below.

The following description of the constituent elements is made in accordance with a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.

In the present specification, the numerical range expressed by the term "to" means a range including numerical values before and after the term "to" as a lower limit value and an upper limit value.

In the present specification, "(meth) acrylic acid" represents a general term of "acrylic acid" and "methacrylic acid".

In the present invention, Re (λ) and Rth (λ) each represent an in-plane retardation and a thickness-direction retardation at a wavelength λ. When not specifically mentioned, the wavelength λ is 550 nm.

In the present invention, Re (. lamda.) and Rth (. lamda.) are values measured at a wavelength of λ in AxoSaccan OPMF-1 (manufactured by Optoscience, Inc.). The average refractive index ((nx + n y + nz)/3) and the film thickness (d (. mu.m)) were input into Axoscan to calculate

Slow axis direction (°)

Re(λ)＝R0(λ)

Rth(λ)＝((nx+ny)/2-nz)×d。

R0 (. lamda.) is a numerical value calculated from AxocandOPMF-1, but represents Re (. lamda.).

In the present specification, the refractive indices nx, ny, and nz are measured using an abbe refractive index (NAR-4T, manufactured by atagoco., ltd.) and a sodium lamp (λ 589nm) as a light source. When the wavelength dependence is measured, the measurement can be performed by combining a multi-wavelength abbe refractometer DR-M2 (ataacoo., ltd.) with an interference filter.

Also, polymer handbook (johnwide & SONS, INC) and the values of the product catalog of various optical films can be used. The values of the average refractive index of the main optical films are illustrated below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49) and polystyrene (1.59).

In the present specification, the angle (for example, an angle such as "90 °") and the relationship (for example, "orthogonal" and "parallel") thereof are considered to include the range of the error allowable in the technical field of the present invention. For example, the term "means that the error from a strict angle" is preferably 5 ° or less, more preferably 3 ° or less, within a range of the strict angle ± 10 °.

[ laminate ]

The laminate of the present invention comprises (laminated) in this order: the optical film comprises a light absorption anisotropic film formed by using a composition containing a dichroic material, and has a transmittance of more than 50% in a wavelength range of 400-700 nm, a lambda/4 plate, and a metal electrode.

In the laminate of the present invention, the following formula (a) is satisfied where P (λ) is a polarization degree (%) of the optical film at a wavelength λ and R (λ) is a reflectance (%) of the metal electrode at the wavelength λ.

Hereinafter, an embodiment of the laminate of the present invention will be described with reference to the drawings. The drawings in the present invention are schematic views, and the size and positional relationship of the layers are not necessarily limited to these embodiments.

Fig. 1 is a schematic side view showing an embodiment of a laminate according to the present invention. The laminate 10 includes an optical film 12, a λ/4 plate 14, and a display element 16 having a metal electrode, not shown, and each member is provided in this order.

The optical film 12 includes a transparent support 12a and a light absorption anisotropic film 12b, and the light absorption anisotropic film 12b is disposed on the λ/4 plate 14 side.

The laminate 10 may have an unillustrated adhesive layer between the optical film 12 and the λ/4 plate 14.

The optical film 12 may have a protective layer, not shown, on the surface of the light absorption anisotropic film 12b opposite to the transparent support 12a side.

The optical film 12 may have an alignment film, not shown, between the transparent support 12a and the light absorption anisotropic film 12 b.

Further, although the case where the optical film 12 has the transparent support 12a is shown, the present invention is not limited thereto, and the optical film in the present invention may not have a transparent support.

[ relationship between degree of polarization and reflectance ]

The laminate of the present invention satisfies the following formula (a) when the polarization degree (%) of the optical film at the wavelength λ is P (λ) and the reflectance (%) of the metal electrode at the wavelength λ is R (λ).

100 x [ min { R (450)/P (450), R (550)/P (550), R (650)/P (650) }/max { R (450)/P (450), R (550)/P (550), R (650)/P (650) } > 85% formula (A)

Wherein, in the formula (a), min { R (450)/P (450), R (550)/P (550), R (650)/P (650) } and max { R (450)/P (450), R (550)/P (550), R (650)/P (650) } respectively represent the minimum value and the maximum value among R (450)/P (450), R (550)/P (550), and R (650)/P (650).

Hereinafter, the value of "R (450)/P (450)" is abbreviated as "X", the value of "R (550)/P (550)" is abbreviated as "Y", and the value of "R (650)/P (650)" is abbreviated as "Z".

Therefore, formula (A) can be replaced with 100 × { min (X, Y, Z)/max (X, Y, Z) } > 85%.

Further, a value calculated by 100 × { min (X, Y, Z)/max (X, Y, Z) } of the formula (a) is abbreviated as "a".

P (λ), which is the degree of polarization (%) of the optical film at the wavelength λ, is a value obtained from the transmittance of the optical film by the formula described in the column of examples described later.

The reflectance (%) of the metal electrode at the wavelength λ, i.e., R (λ), was determined from the reflectance spectrum measured with a spectrophotometer using a deposited film of the metal constituting the metal electrode formed on the polyester film.

In the laminate 10 shown in fig. 1, when the surface of the optical film 12 opposite to the λ/4 plate 14 side (i.e., the transparent support 12a side) is set to the viewing side, a part of light incident from the surface of the transparent support 12a passes through the optical film 12 and the λ/4 plate 14 and reaches the metal electrode in the display element 16. In this case, when a part of the reflected light that is incident on the metal electrode and reflected transmits through the optical film 12, the reflected light of the metal electrode is visually recognized by the observer.

Here, fig. 2 shows an example of a reflection spectrum of a general metal, and the ordinate represents the reflectance R (%) and the abscissa represents the wavelength λ (nm). As shown in FIG. 2, the reflection spectrum of a metal in the visible light region (400 to 700nm) tends to increase as it shifts to the longer wavelength side. Therefore, according to the reflection spectrum of fig. 2, the red color tone of the reflected light of the metal is strong.

In general, when an optical film having a low light transmittance is used, the reflected light from the metal electrode is absorbed by the absorption axis of the dichroic material of the light absorption anisotropic film, and therefore the problem of discoloration of the reflected light is unlikely to occur.

On the other hand, when an optical film having a high light transmittance is used to display a clear image on an image display device, a part of the reflected light from the metal electrode is transmitted through the viewing side of the optical film without being absorbed by the absorption axis of the dichroic material of the light absorption anisotropic film, and therefore, there is a problem that the observer sees more discolored light.

In view of the above problems, the present inventors have found that discoloration of reflected light from a metal electrode can be suppressed by adjusting the degree of polarization of an optical film for each wavelength based on the reflection spectrum of the metal constituting the metal electrode.

Here, fig. 3 is a graph showing the degree of polarization P (%) of the optical film for each wavelength. As shown in fig. 3, when an optical film whose polarization degree P increases as it shifts to the longer wavelength side is used, the optical film (dichroic material) easily absorbs light on the longer wavelength side.

That is, it is estimated that, as shown in fig. 4, when the value (R/P) obtained by dividing the reflectance R (%) of the metal by the polarization degree P (%) of the optical film is the same for each wavelength, the discoloration of the reflected light that is transmitted through the optical film and is visually recognized can be suppressed.

From such a viewpoint, the present inventors have found the following: by selecting wavelengths (450nm, 550nm, and 650nm) representative of the wavelength ranges of 3 primary colors of light, i.e., blue, green, and red, when the variation in the R/P value (i.e., X, Y and Z in formula (a)) for each wavelength is small, discoloration of reflected light that is visually recognized through the optical film can be suppressed. Specifically, when the ratio of the minimum value (min (X, Y, Z)) to the maximum value (max (X, Y, Z)) in X, Y, Z of formula (a) is 85% or more, the state is close to the state shown in fig. 4 where the difference between R/P for each wavelength is small, and therefore discoloration of reflected light that is visible through the optical film can be suppressed.

The above a is 85% or more, and from the viewpoint of further suppressing the discoloration of the reflected light, 88% or more is preferable, and 90% or more is particularly preferable. The upper limit of A is preferably 100% or less.

Preferably, Y does not satisfy min (X, Y, Z) and does not satisfy max (X, Y, Z). That is, in X, Y and Z, Y is preferably an intermediate value. Y is a value corresponding to a wavelength which is easily recognized by human eyes. Therefore, if Y is an intermediate value that does not match any of the maximum value and the minimum value, the discoloration of the reflected light is not easily visible.

Also, it is preferable that X corresponds to min (X, Y, Z) and Z corresponds to max (X, Y, Z). That is, the relationship of X < Y < Z is preferably satisfied. This can further suppress discoloration of the reflected light.

The optical film preferably has a maximum value of polarization degree in a range of 555 to 700nm, and satisfies P (450) < P (550). Thus, the polarization degree P of the optical film per wavelength corresponds to a reflection spectrum of a general metal in which the reflectance R becomes higher as it shifts to the longer wavelength side. Therefore, discoloration of the reflected light can be further suppressed.

The respective members constituting the laminate of the present invention will be described below.

[ optical film ]

The optical film has a transmittance of more than 50%, preferably 52% or more, and particularly preferably 55% or more in a wavelength range of 400 to 700 nm. This enables a clear pattern to be displayed on the display panel.

The transmittance of the optical film in the present specification means a transmittance obtained by correcting visibility with reference to a TAC substrate and using CIE (international commission on illumination) standard specific visibility in order to suppress the influence of surface reflection, based on the transmittance of the optical film in a wavelength range of 400 to 700 nm. The details of the apparatus and the method for measuring the transmittance of an optical film are shown in the following example column.

The method of adjusting the transmittance of the optical film to 50% or more is not limited to this, and a method of using an organic dye (particularly, a specific dichroic material described later) as the dichroic material contained in the light absorption anisotropic film may be mentioned.

For example, the degree of polarization of the optical film can be adjusted by the type of dichroic substance, the content of the dichroic substance in the light absorption anisotropic film, or the blend ratio of the respective dichroic substances when a plurality of dichroic substances are used.

< light-absorbing Anisotropic film >

The optical film has a light-absorbing anisotropic film. The light absorption anisotropic film is a film formed using a composition containing a dichroic substance. The optical film functions as a linearly polarizing plate for extracting linearly polarized light.

(dichroic substance)

The dichroic material is not particularly limited as long as an optical film having high light transmittance (light transmittance of 50% or more) can be obtained, but preferably contains a compound represented by the following formula (1) (hereinafter, also simply referred to as "specific dichroic material") from the viewpoint of excellent orientation.

The light absorption anisotropic film may contain the following dichroic substance itself, may contain a polymer of the following dichroic substance, or may contain both of them.

[ chemical formula 1]

Wherein, in the formula (1), A¹、A²And A³Each independently represents an aromatic group having a valence of 2 which may have a substituent.

And, in the formula (1), L¹And L²Each independently represents a substituent.

In the formula (1), m represents an integer of 1 to 4, and when m is an integer of 2 to 4, a plurality of A²May be the same as or different from each other. In addition, m is excellentIs selected as 1 or 2.

For A in the formula (1)¹、A²And A³The expression "an aromatic group having a valence of 2 which may have a substituent" will be described.

Examples of the substituent include substituent group G described in paragraphs [0237] to [0240] of Japanese patent application laid-open No. 2011-237513, in which a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group (e.g., methoxycarbonyl, ethoxycarbonyl, etc.) or an aryloxycarbonyl group (e.g., phenoxycarbonyl, 4-methylphenoxycarbonyl, 4-methoxyphenylcarbonyl, etc.) is preferable, an alkyl group is particularly preferable, and an alkyl group having 1 to 5 carbon atoms is more preferable.

On the other hand, as the 2-valent aromatic group, for example, can be cited 2-valent aromatic hydrocarbon group and 2-valent aromatic heterocyclic group.

Examples of the aromatic hydrocarbon group having a valence of 2 include an arylene group having 6 to 12 carbon atoms, and specific examples thereof include a phenylene group, a cumeneene group, a mesitylene group, a tolylene group, and a xylylene group. Among them, phenylene group is preferable.

The aromatic heterocyclic group having a valence of 2 is preferably a group derived from a monocyclic or 2-membered heterocyclic ring. Examples of the atom other than carbon constituting the aromatic heterocyclic group include a nitrogen atom, a sulfur atom and an oxygen atom. When the aromatic heterocyclic group has a plurality of ring-constituting atoms other than carbon, they may be the same or different. Specific examples of the aromatic heterocyclic group include pyridylene (pyridine-diyl), quinolylene (quinoline-diyl), isoquinolylene (isoquinoline-diyl), benzothiadiazole-diyl, phthalimide-diyl, and thienothiazole-diyl (hereinafter, simply referred to as "thienothiazolyl").

Among the above aromatic groups having a valence of 2, aromatic hydrocarbon groups having a valence of 2 are preferred.

Here, A is preferred¹、A²And A³Any of which is a thienothiazolyl group having a valence of 2 which may have a substituent. In addition, specific examples of the substituent of the 2-valent thienothiazolyl group are as described above "The substituents in the "2-valent aromatic group which may have a substituent" are the same, and the preferred embodiments are also the same.

And, more preferably A¹、A²And A³A in (A)²Is a thienothiazolyl group having a valence of 2. In this case, A¹And A²Represents an aromatic group having a valence of 2 which may have a substituent.

When A is²When the compound is a thienothiazolyl group having a valence of 2, A is preferred¹And A²At least one of them is an optionally substituted aromatic hydrocarbon group having a valence of 2, more preferably A¹And A²Both of these are 2-valent aromatic hydrocarbon groups which may have a substituent.

For L in the formula (1)¹And L²The "substituent" is illustrated.

The substituent is preferably a group introduced for improving solubility or nematic liquid crystallinity, a group having an electron donating property or an electron withdrawing property introduced for adjusting the color tone of the dye, or a group having a crosslinkable group (polymerizable group) introduced for fixing the orientation.

Examples of the substituent include an alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, even more preferably 1 to 8 carbon atoms, for example, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a n-octyl group, a n-decyl group, a n-hexadecyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group and the like), an alkenyl group (preferably an alkenyl group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, even more preferably 2 to 8 carbon atoms, for example, a vinyl group, an allyl group, a 2-butenyl group, a 3-pentenyl group and the like), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, even more preferably 2 to 8 carbon atoms, for example, a propargyl group, a 3-pentenyl group and the like), an aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, even more preferably 6 to 12 carbon atoms, examples thereof include a phenyl group, a 2, 6-diethylphenyl group, a 3, 5-bistrifluoromethylphenyl group, a styryl group, a naphthyl group, and a biphenyl group, a substituted or unsubstituted amino group (preferably an amino group having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, for example an unsubstituted amino group, methylamino group, dimethylamino group, diethylamino group, and anilino group), an alkoxy group (preferably a amino group having 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, for example a methoxy group, an ethoxy group, and a butoxy group), an oxycarbonyl group (preferably a carbon number of 2 to 20 carbon atoms, more preferably a carbon number of 2 to 15 carbon atoms, particularly preferably a carbon number of 2 to 10 carbon atoms, for example a methoxycarbonyl group, an ethoxycarbonyl group, and a phenoxycarbonyl group), an acyloxy group (preferably a carbon number of 2 to 20, more preferably a carbon number of 2 to 10, particularly preferably 2 to 6 carbon atoms, for example, acetoxy, benzoyloxy, acryloyl, methacryloyl and the like, acylamino (preferably 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms, particularly preferably 2 to 6 carbon atoms, for example, acetylamino, benzoylamino and the like), alkoxycarbonylamino (preferably 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms, particularly preferably 2 to 6 carbon atoms, for example, methoxycarbonylamino and the like), aryloxycarbonylamino (preferably 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, for example, benzyloxycarbonylamino and the like), sulfonylamino (preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, particularly preferably 1 to 6 carbon atoms, for example, methanesulfonylamino, benzenesulfonylamino and the like), A sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably having 0 to 10 carbon atoms, even more preferably having 0 to 6 carbon atoms, and examples thereof include a sulfamoyl group, a methylsulfamoyl group, a dimethylsulfamoyl group, and a phenylsulfamoyl group), a carbamoyl group (preferably having 1 to 20 carbon atoms, even more preferably having 1 to 10 carbon atoms, even more preferably having 1 to 6 carbon atoms, and examples thereof include an unsubstituted carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, and a phenylcarbamoyl group), an alkylthio group (preferably having 1 to 20 carbon atoms, even more preferably having 1 to 10 carbon atoms, even more preferably having 1 to 6 carbon atoms, and examples thereof include a methylthio group and an ethylthio group), an arylthio group (preferably having 6 to 20 carbon atoms, even more preferably having 6 to 16 carbon atoms, even more preferably having 6 to 12 carbon atoms, and examples thereof include a phenylthio group), a sulfonyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, particularly preferably 1 to 6 carbon atoms, and examples thereof include methanesulfonyl and toluenesulfonyl, sulfinyl (preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, particularly preferably 1 to 6 carbon atoms, examples thereof include methanesulfinyl group, benzenesulfinyl group and the like), ureido group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 10 carbon atoms, particularly preferably having 1 to 6 carbon atoms, examples thereof include unsubstituted ureido groups, methylureido groups, phenylureido groups and the like), phosphoric acid amido groups (preferably having 1 to 20 carbon atoms, more preferably having 1 to 10 carbon atoms, particularly preferably having 1 to 6 carbon atoms, examples thereof include a diethylphosphoramidate group and a phenylphosphonate group), a hydroxyl group, a mercapto group, and a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom). ) Cyano groups, nitro groups, hydroxamic acid groups, sulfinyl groups, hydrazino groups, imino groups, azo groups, heterocyclic groups (preferably heterocyclic groups having 1 to 30, more preferably 1 to 12 carbon atoms, for example heterocyclic groups having heteroatoms such as nitrogen atoms, oxygen atoms, and sulfur atoms, for example epoxy groups, oxetanyl groups, imidazolyl groups, pyridyl groups, quinolyl groups, furyl groups, piperidyl groups, morpholinyl groups, benzoxazolyl groups, benzimidazolyl groups, and benzothiazolyl groups), silyl groups (preferably silyl groups having 3 to 40, more preferably 3 to 30, particularly preferably 3 to 24 carbon atoms, for example trimethylsilyl groups, triphenylsilyl groups), and the like.

These substituents may be further substituted with these substituents. When two or more substituents are present, they may be the same or different. And, when possible, may bond to each other to form a ring.

As L¹And L²The substituent(s) is preferably an alkyl group which may have a substituent(s), an alkenyl group which may have a substituent(s), an alkynyl group which may have a substituent(s), an aryl group which may have a substituent(s), an alkoxy group which may have a substituent(s), an oxycarbonyl group which may have a substituent(s), an acyloxy group which may have a substituent(s), an acylamino group which may have a substituent(s), an amino group which may have a substituent(s), an alkoxycarbonylamino group which may have a substituent(s), a sulfonamido group which may have a substituent(s), a sulfamoyl group which may have a substituent(s), a pharmaceutically acceptable,The substituent(s) may be selected from the group consisting of a carbamoyl group which may have a substituent(s), an alkylthio group which may have a substituent(s), a sulfonyl group which may have a substituent(s), a ureido group which may have a substituent(s), a nitro group, a hydroxyl group, a cyano group, an imino group, an azo group, a halogen atom and a heterocyclic group, and more preferably an alkyl group which may have a substituent(s), an alkenyl group which may have a substituent(s), an aryl group which may have a substituent(s), an alkoxy group which may have a substituent(s), an oxycarbonyl group which may have a substituent(s), an acyloxy group which may have a substituent(s).

Preferably L¹And L²At least one of them contains a crosslinkable group (polymerizable group), more preferably L¹And L²Both of these groups contain a crosslinkable group.

Specific examples of the crosslinkable group include polymerizable groups described in paragraphs [0040] to [0050] of jp 2010-244038 a, and from the viewpoints of reactivity and synthesis applicability, an acryloyl group, a methacryloyl group, an epoxy group, an oxetanyl group, or a styryl group is preferable, and an acryloyl group or a methacryloyl group is preferable.

As L¹And L²Preferable examples of the (C) group include an alkyl group substituted with the crosslinkable group, a dialkylamino group substituted with the crosslinkable group, and an alkoxy group substituted with the crosslinkable group.

In the present invention, it is preferable that the specific dichroic substance is a compound represented by the following formula (2) for the reason that the degree of orientation of the specific dichroic substance contained in the light absorption anisotropic film is further improved.

[ chemical formula 2]

Wherein, in the formula (2), A⁴Represents an aromatic group having a valence of 2 which may have a substituent.

And, in the formula (2), L³And L⁴Each independently represents a substituent.

In formula (2), E represents any one atom of a nitrogen atom, an oxygen atom and a sulfur atom.

And, in the formula (2), R¹Represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent.

And, in the formula (2), R²Represents a hydrogen atom or an alkyl group which may have a substituent.

And, in the formula (2), R³Represents a hydrogen atom or a substituent.

In the formula (2), n represents 0 or 1. Wherein n is 1 when E is a nitrogen atom, and n is 0 when E is an oxygen atom or a sulfur atom.

In the above formula (2), A⁴Specific examples and preferred embodiments of the "optionally substituted 2-valent aromatic group" and A in the above formula (1)¹～A³The "2-valent aromatic group which may have a substituent" is the same.

As A⁴In a preferred embodiment, the group is phenylene.

In the above formula (2), L³And L⁴Specific examples and preferred embodiments of the "substituent" are the same as those of L in the above formula (1)¹And L²The "substituents" are the same.

As L³And L⁴Is preferably L³And L⁴At least one of them contains a crosslinkable group, and more preferably L³And L⁴Both of these contain a crosslinkable group. This further improves the degree of orientation of the specific dichroic material contained in the light-absorbing anisotropic film, and improves the high-temperature durability and the moist-heat durability of the laminate.

And as L³And L⁴The crosslinkable group of (2) is preferably an acryloyl group or a methacryloyl group.

In the formula (2), E represents any one atom of a nitrogen atom, an oxygen atom and a sulfur atom, and is preferably a nitrogen atom from the viewpoint of synthesis applicability.

In addition, E in the formula (1) is preferably an oxygen atom from the viewpoint of easily allowing the specific dichroic substance to have absorption on the short wavelength side (for example, having a maximum absorption wavelength in the vicinity of 500 to 530 nm).

On the other hand, E in the formula (1) is preferably a nitrogen atom from the viewpoint of easily allowing the specific dichroic substance to have absorption on the long wavelength side (for example, having a maximum absorption wavelength in the vicinity of 600 nm).

In the above formula (2), R¹Represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent or an alkoxy group which may have a substituent, and is preferably a hydrogen atom or an alkyl group which may have a substituent.

Then, to R¹The "alkyl group which may have a substituent" and the "alkoxy group which may have a substituent" are described.

Examples of the substituent include a halogen atom and the like.

Examples of the alkyl group include linear, branched or cyclic alkyl groups having 1 to 8 carbon atoms. Among them, a linear alkyl group having 1 to 6 carbon atoms is preferable, a linear alkyl group having 1 to 3 carbon atoms is more preferable, and a methyl group or an ethyl group is further preferable.

Examples of the alkoxy group include alkoxy groups having 1 to 8 carbon atoms. Among them, preferred is an alkoxy group having 1 to 6 carbon atoms, more preferred is an alkoxy group having 1 to 3 carbon atoms, and particularly preferred is a methoxy group or an ethoxy group.

In the above formula (2), R²Represents a hydrogen atom or an alkyl group which may have a substituent, and is preferably an alkyl group which may have a substituent.

R²Specific examples and preferred embodiments of the "alkyl group which may have a substituent" and R in the formula (2)¹The "alkyl group which may have a substituent" in (1) is the same, and therefore, the description thereof is omitted.

In addition, when E is a nitrogen atom, R²The group represented by formula (2) is a group (i.e., n is 1). On the other hand, when E is an oxygen atom or a sulfur atom, R²A group not present in formula (2) (that is, when n is 0) is formed.

In the above formula (2), R³Represents a hydrogen atom or a hydrogen atomAnd (4) generation of base.

R³Specific examples and preferred embodiments of the "substituent" are the same as those of the "aromatic group having a valence of 2 which may have a substituent" described above, and the preferred embodiments are also the same, and therefore, the description thereof is omitted.

In the formula (2), n represents 0 or 1. Wherein n is 1 when E is a nitrogen atom, and n is 0 when E is an oxygen atom or a sulfur atom.

Specific examples of the specific dichroic substance represented by the above formula (1) include compounds described in paragraphs [0051] to [0081] of Japanese patent application laid-open No. 2010-152351, the contents of which are incorporated herein.

Among these, as the specific dichroic material having the structure represented by the above formula (2), in addition to the compounds (D-1) to (D-53) described in paragraphs [0074] to [0081] of Japanese patent application laid-open No. 2010-152351, the following compounds (D-54) to (D-58) can be preferably mentioned.

[ chemical formula 3]

The content of the dichroic material is preferably 25% by mass or less, more preferably 20% by mass or less, and particularly preferably 18% by mass or less, based on the total mass of the total solid components of the composition. The lower limit of the content of the dichroic material is preferably 5% by mass or more, more preferably 8% by mass or more, and particularly preferably 10% by mass or more, based on the total mass of the total solid content of the composition.

When the content of the dichroic material is 25% by mass or less, a thin film having high light transmittance can be obtained, and thus a clear pattern (for example, an image or a character) can be displayed on the display panel. When the content of the dichroic material is 5% by mass or more, the function of the optical film can be sufficiently exhibited when the optical film is used as an antireflection film.

In the present invention, the light-absorbing anisotropic film is preferably a film formed using a composition containing a liquid crystalline compound together with the above dichroic substance (hereinafter, also referred to as "liquid crystalline composition") for the reason that the dichroic substance can be aligned with a higher degree of orientation while suppressing deposition of the dichroic substance.

(liquid Crystal Compound)

As the liquid crystalline compound contained in the liquid crystalline composition, any of a low molecular liquid crystalline compound and a high molecular liquid crystalline compound can be used.

Here, the "low-molecular liquid crystalline compound" refers to a liquid crystalline compound having no repeating unit in its chemical structure.

The "polymeric liquid crystalline compound" refers to a liquid crystalline compound having a repeating unit in its chemical structure.

Examples of the low-molecular liquid crystalline compound include those described in Japanese patent laid-open publication No. 2013-228706.

Examples of the polymer liquid crystalline compound include thermotropic liquid crystalline polymers described in Japanese patent application laid-open No. 2011-237513. The liquid crystalline polymer compound may have a crosslinkable group (for example, an acryloyl group or a methacryloyl group) at the end.

(surface modifying agent)

The liquid crystalline composition preferably contains a surface modifier. By including the surface modifier, it is expected that the smoothness of the coated surface is improved and the degree of orientation is improved, and that the in-plane uniformity is improved by suppressing the dishing and the unevenness.

As the surface modifier, a surface modifier which makes the liquid crystalline compound horizontal on the coating surface side is preferable, and the compounds (horizontal orientation agents) described in paragraphs [0253] to [0293] of Japanese patent laid-open publication No. 2011-237513 can be used.

When the liquid crystalline composition contains the surface modifier, the content of the surface modifier is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, based on 100 parts by mass of the total of the dichroic material and the liquid crystalline compound in the liquid crystalline composition.

(polymerization initiator)

The liquid crystalline composition may contain a polymerization initiator.

The polymerization initiator is not particularly limited, but is preferably a photopolymerization initiator which is a photosensitive compound.

As the photopolymerization initiator, various compounds can be used without particular limitation. Examples of the photopolymerization initiator include an α -carbonyl compound (see U.S. Pat. No. 2367661 and U.S. Pat. No. 2367670), an acyloin ether (see U.S. Pat. No. 2448828), an α -hydrocarbon-substituted aromatic acyloin compound (see U.S. Pat. No. 2722512), a polyquinone compound (see U.S. Pat. No. 3046127 and U.S. Pat. No. 2951758), combinations of triarylimidazole dimer and p-aminophenyl ketone (U.S. Pat. No. 3549367), acridine and phenazine compounds (Japanese patent laid-open No. 60-105667 and U.S. Pat. No. 4239850), oxadiazole compounds (U.S. Pat. No. 4212970), and acylphosphine oxide compounds (Japanese patent publication No. 63-040799, Japanese patent publication No. 5-029234, Japanese patent laid-open No. 10-095788, and Japanese patent laid-open No. 10-029997).

As such photopolymerization initiators, commercially available ones can be used, and examples thereof include IRGACURE184, IRGACURE907, IRGACURE369, IRGACURE651, IRGACURE819, and IRGACURE OXE-01 manufactured by BASF corporation.

When the liquid crystalline composition of the present invention contains a polymerization initiator, the content of the polymerization initiator is preferably 0.01 to 30 parts by mass, and more preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the total of the dichroic material and the liquid crystalline compound in the liquid crystalline composition. When the content of the polymerization initiator is 0.01 parts by mass or more, curability of the light absorption anisotropic film becomes good, and when the content is 30 parts by mass or less, orientation of the light absorption anisotropic film becomes good.

(solvent)

The liquid crystalline composition preferably contains a solvent from the viewpoint of handling properties and the like.

Examples of the solvent include ketones (e.g., acetone, 2-butanone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone), ethers (e.g., dioxane, tetrahydrofuran), aliphatic hydrocarbons (e.g., hexane), alicyclic hydrocarbons (e.g., cyclohexane), aromatic hydrocarbons (e.g., benzene, toluene, xylene, and trimethylbenzene), halogenated carbons (e.g., dichloromethane, chloroform, dichloroethane, dichlorobenzene, and chlorotoluene), esters (e.g., methyl acetate, ethyl acetate, and butyl acetate), alcohols (e.g., ethanol, isopropanol, butanol, and cyclohexanol), cellosolves (e.g., methyl cellosolve, ethyl cellosolve, and 1, 2-dimethoxyethane), cellosolves, sulfoxides (e.g., dimethyl sulfoxide), amides (e.g., dimethylformamide, dimethylacetamide, etc.) and a heterocyclic compound (e.g., pyridine, etc.), and water. These solvents may be used alone or in combination of two or more.

Among these solvents, organic solvents are preferably used, and halocarbons or ketones are more preferably used.

When the liquid crystalline composition contains a solvent, the content of the solvent is preferably 80 to 99% by mass, more preferably 83 to 97% by mass, and particularly preferably 85 to 95% by mass, based on the total mass of the liquid crystalline composition.

(other Components)

The liquid crystalline composition may further contain a dichroic substance other than the above-described specific dichroic substance, and may contain a plurality of the above-described specific dichroic substances. When a plurality of dichroic materials are contained, from the viewpoint of further curing the liquid crystalline composition, the dichroic materials preferably contain a crosslinkable group that crosslinks with the specific dichroic material, and more preferably contain a plurality of specific dichroic materials.

(method of formation)

The method for forming the light-absorbing anisotropic film using the liquid crystalline composition is not particularly limited, and a method comprising the following steps in this order may be mentioned: a step of applying the liquid crystalline composition to a transparent support described later to form a coating film (hereinafter, also referred to as "coating film forming step"); and a step of aligning the liquid crystalline component contained in the coating film (hereinafter, also referred to as "alignment step").

The liquid crystalline component is a component containing a dichroic material having liquid crystallinity, in addition to the liquid crystalline compound, when the dichroic material has liquid crystallinity.

The coating film forming step is a step of forming a coating film by coating the liquid crystalline composition on a transparent support.

By using the liquid crystalline composition containing a solvent or a liquid crystalline composition which is formed into a liquid material such as a melt by heating or the like, the liquid crystalline composition can be easily applied to a transparent support.

Specific examples of the method for applying the liquid crystalline composition include known methods such as a roll coating method, a gravure printing method, a spin coating method, a bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method, a spray coating method, and an ink jet method.

In this embodiment, an example in which the liquid crystalline composition is applied to the transparent support is shown, but the liquid crystalline composition is not limited to this, and for example, the liquid crystalline composition may be applied to an alignment film provided on the transparent support. The details of the alignment film will be described later.

The alignment step is a step of aligning the liquid crystalline component contained in the coating film. Thus, a light absorption anisotropic film can be obtained.

The orientation process may have a drying treatment. By the drying treatment, components such as a solvent can be removed from the coating film. The drying treatment may be performed by a method of leaving the coating film at room temperature for a predetermined time (for example, natural drying), or may be performed by a method of heating and/or blowing air.

Here, the liquid crystalline component contained in the liquid crystalline composition may be aligned by the coating film forming step or the drying treatment. For example, in a mode in which a liquid crystalline composition is prepared as a coating liquid containing a solvent, a coating film having light absorption anisotropy (i.e., a light absorption anisotropic film) can be obtained by drying the coating film to remove the solvent from the coating film.

When the drying treatment is performed at a temperature equal to or higher than the transition temperature at which the liquid crystalline component contained in the coating film is converted into the liquid crystal phase, the heating treatment described later may not be performed.

From the viewpoint of production applicability and the like, the transition temperature at which the liquid crystalline component contained in the coating film changes to a liquid crystal phase is preferably 10 to 250 ℃, and more preferably 25 to 190 ℃. When the transition temperature is 10 ℃ or higher, a cooling treatment for lowering the temperature to a temperature range in which the liquid crystal phase is formed is not necessary, and therefore, it is preferable. Further, when the transition temperature is 250 ℃ or lower, it is preferable that the temperature is not higher even in the case of an isotropic liquid state having a higher temperature than the temperature range in which the liquid crystal phase is temporarily present, since the waste of heat energy and the deformation and alteration of the substrate can be reduced.

The orientation step preferably includes a heat treatment. This enables the liquid crystalline component contained in the coating film to be aligned, and therefore the coating film after the heat treatment can be preferably used as a light absorption anisotropic film.

The heat treatment is preferably 10 to 250 ℃ and more preferably 25 to 190 ℃ from the viewpoint of manufacturing applicability and the like. The heating time is preferably 1 to 300 seconds, more preferably 1 to 60 seconds.

The orientation process may have a cooling process performed after the heating process. The cooling treatment is a treatment of cooling the heated coating film to about room temperature (20 to 25 ℃). This makes it possible to fix the alignment of the liquid crystalline component contained in the coating film. The cooling method is not particularly limited, and can be performed by a known method.

Through the above steps, a light absorption anisotropic film can be obtained.

In this embodiment, the method of aligning the liquid crystalline component contained in the coating film includes, for example, a drying treatment and a heating treatment, but is not limited thereto and can be performed by a known alignment treatment.

The method for producing the light absorption anisotropic film may include a step of curing the light absorption anisotropic film (hereinafter, also referred to as a "curing step") after the alignment step.

For example, when the light absorption anisotropic film has a crosslinkable group (polymerizable group), the curing step is performed by heating and/or light irradiation (exposure). Among them, the curing step is preferably performed by light irradiation.

The light source used for curing can be any of various light sources such as infrared light, visible light, and ultraviolet light, but ultraviolet light is preferable. In addition, the ultraviolet ray may be irradiated while heating at the time of curing, or may be irradiated through a filter which transmits only a specific wavelength.

When the exposure is performed while heating, the heating temperature at the time of exposure depends on the transition temperature at which the liquid crystalline component contained in the light absorption anisotropic film is converted into the liquid crystal phase, but is preferably 25 to 140 ℃.

Further, the exposure may be performed under a nitrogen atmosphere. When the light-absorbing anisotropic film is cured by radical polymerization, inhibition of polymerization by oxygen can be reduced, and therefore, exposure is preferably performed in a nitrogen atmosphere.

The thickness of the light absorption anisotropic film is not particularly limited, but is preferably 0.1 to 5.0. mu.m, more preferably 0.3 to 1.5. mu.m.

< transparent support >

The optical film may have a transparent support. When the optical film has a transparent support, the transparent support is disposed between the light-absorbing anisotropic film and the λ/4 plate.

Here, in the present invention, "transparent" means that the visible light transmittance is 60% or more, preferably 80% or more, and particularly preferably 90% or more.

Examples of the material for forming the transparent support include polycarbonate-based polymers; polyester polymers such as polyethylene terephthalate (PET) and polyethylene naphthalate; acrylic polymers such as polymethyl methacrylate; styrene polymers such AS polystyrene and acrylonitrile/styrene copolymers (AS resins); polyolefin polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers; vinyl chloride-based polymers; amide polymers such as nylon and aromatic polyamide; an imide polymer; sulfone polymers; polyether sulfone polymers; polyether ether ketone polymers; polyphenylene sulfide-based polymers; vinylidene chloride-based polymers; a vinyl alcohol polymer; vinyl butyral polymers; an aromatic ester polymer; polyoxymethylene polymers; epoxy polymers, and the like.

The material for forming the transparent support is preferably a thermoplastic norbornene-based resin. Examples of the thermoplastic norbornene-based resin include ZEONEX and ZEONOR manufactured by zeon corporation and ARTON manufactured by JSRCorporation.

As a material for forming the transparent support, a cellulose-based polymer typified by triacetyl cellulose (TAC) is also preferable.

The thickness of the transparent support is not particularly limited, but is preferably 100 μm or less, more preferably 80 μm or less, and particularly preferably 10 to 80 μm.

[ lambda/4 plate ]

The lambda/4 plate of the laminate of the present invention is disposed between the optical film and the metal electrode. In the laminate of the present invention, the combination of the optical film and the λ/4 plate can be used as a circularly polarizing plate.

Here, the "λ/4 plate" refers to a plate having a λ/4 function, specifically, a plate having a function of converting linearly polarized light of a certain specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light).

Specific examples of the λ/4 plate include U.S. patent application publication No. 2015/0277006.

For example, as an embodiment in which the λ/4 plate has a single-layer structure, specifically, a stretched polymer film, a retardation film in which an optically anisotropic layer having a λ/4 function is provided on a support, or the like can be given, and as an embodiment in which the λ/4 plate has a multilayer structure, specifically, a broadband λ/4 plate in which a λ/4 plate and a λ/2 plate are laminated can be given.

The Re (550) of the λ/4 plate is not particularly limited, but is preferably 110 to 160nm, more preferably 120 to 150nm, from the viewpoint of being useful as a λ/4 plate.

The λ/4 plate preferably exhibits reverse wavelength dispersion. The λ/4 plate exhibits inverse wavelength dispersibility means that when the in-plane retardation (Re) value at a specific wavelength (visible light range) is measured, the Re value becomes equal or higher as the measurement wavelength becomes larger.

[ Metal electrode ]

The metal electrode included in the laminate of the present invention is preferably an electrode included in a display element or an electrode included in a touch sensor, for example.

The display element is an element used in a display device, and specifically includes a liquid crystal cell, an organic electroluminescence (hereinafter, abbreviated as "EL") display panel, a plasma display panel, and the like, and among these, an organic EL display panel is preferable.

An organic EL display panel is a display panel configured using organic EL elements in which an organic light-emitting layer (organic electroluminescent layer) is sandwiched between metal electrodes (between a cathode and an anode).

The touch sensor is a sensor that senses a change in capacitance, pressure, or the like, and is applied to the image display device and used as a touch panel. Specifically, the touch sensor may be a touch sensor having a conductive thin film in which a metal electrode is disposed on a surface of the thin film.

Examples of the material constituting the metal electrode include metal elements selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, tin, zinc, indium, and the like, and alloys containing one or more of the above metal elements.

As a material constituting the metal electrode, a metal oxide or a metal nitride having conductivity can be used.

Examples of the metal oxide having conductivity include indium tin oxide, indium oxide containing tungsten, indium zinc oxide containing tungsten, indium oxide containing titanium, indium tin oxide containing titanium, indium zinc oxide, indium tin oxide to which silicon is added, and the like.

Examples of the metal nitride having conductivity include titanium nitride, tantalum nitride, and tungsten nitride.

Among these, as a material constituting the metal, a material containing silver is preferable from the viewpoint of conductivity and handling property, and silver is preferable.

[ alignment film ]

The laminate of the present invention may have an alignment film between the transparent support and the light-absorbing anisotropic film.

Examples of the method for forming the alignment film include rubbing treatment of the film surface of an organic compound (preferably a polymer), oblique vapor deposition of an inorganic compound, formation of a layer having microgrooves, and accumulation of an organic compound (for example, ω -tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearate, or the like) by the langmuir blodgett method (LB film). Also, an alignment film that generates an alignment function by application of an electric field, application of a magnetic field, or light irradiation is known.

Among them, in the present invention, an alignment film formed by rubbing treatment is preferable from the viewpoint of easiness of control of the pretilt angle of the alignment film, and a photo-alignment film formed by light irradiation is also preferable from the viewpoint of uniformity of alignment.

< rubbing treatment of oriented film >

As a polymer material used for an alignment film formed by rubbing treatment, there are many documents and many commercially available products are available. In the present invention, polyvinyl alcohol or polyimide and derivatives thereof are preferably used. As for the alignment film, reference can be made to the description on page 43, line 24 to page 49, line 8 of International publication WO01/88574A 1. The thickness of the alignment film is preferably 0.01 to 10 μm, more preferably 0.01 to 1 μm.

< photoalignment film >

Many documents describe photo-alignment compounds used for alignment films formed by light irradiation. Preferable examples of the compound of the present invention include, for example, compounds of maleimide and/or alkenyl-substituted diimide having a photo-orientation unit as described in Japanese patent laid-open Nos. 2006-285197, 2007-076839, 2007-138138, 2007-094071, 2007-121721, 2007-140465, 2007-156439, 2007-133184, 2009-109831, 3883848, 4151746, 2002-229039, 2002-265541, 2002-317013, 3973, 4205195, A photocrosslinkable silane derivative described in Japanese patent No. 4205198, a photocrosslinkable polyimide, polyamide or polyester described in Japanese patent laid-open Nos. 2003-520878, 2004-529220 or 4162850.

Among these, as the photo-alignment compound, a photosensitive compound having a photoreactive group that generates at least one of dimerization and isomerization by the action of light is preferably used.

Further, the photoreactive group preferably has a skeleton of at least one derivative or compound selected from the group consisting of a cinnamic acid derivative, a coumarin derivative, a chalcone derivative, a maleimide derivative, an azobenzene compound, a polyimide compound, a stilbene compound, and a spiropyran compound.

The photo alignment film is manufactured by irradiating a photo alignment film formed of the above material with linearly polarized light or non-polarized light.

In the present specification, "irradiation with linearly polarized light" and "irradiation with unpolarized light" refer to operations for causing photoreaction of the photo-alignment material. The wavelength of the light to be used differs depending on the photo-alignment material to be used, and is not particularly limited as long as it is a wavelength required for the photoreaction. The peak wavelength of light used for light irradiation is preferably 200 to 700nm, and more preferably ultraviolet light having a peak wavelength of 400nm or less.

Examples of the light source used for the light irradiation include commonly used light sources such as a tungsten lamp, a halogen lamp, a xenon flash lamp, a mercury xenon lamp, a carbon arc lamp, and the like, various lasers [ for example, a semiconductor laser, a helium-neon laser, an argon ion laser, a helium-cadmium laser, and a YAG (yttrium aluminum garnet) laser ], a light emitting diode, and a cathode ray tube.

As a method for obtaining linearly polarized light, a method using a polarizing plate (for example, an iodine polarizing plate, a dichroic dye polarizing plate, and a wire grid polarizing plate), a method using a prism-type element (for example, a glan-thomson prism), a reflective polarizer using a brewster angle, or a method using light emitted from a laser light source having polarized light can be used. Further, only light of a desired wavelength may be selectively irradiated using a filter, a wavelength conversion element, or the like.

When the irradiated light is linearly polarized light, a method of irradiating light perpendicularly or obliquely from the upper surface to the alignment film or from the back surface to the surface of the alignment film is employed. The incident angle of light varies depending on the photo-alignment material, and is preferably 0 to 90 ° (vertical), more preferably 40 to 90 °.

When the light is unpolarized, the unpolarized light is obliquely irradiated to the alignment film. The incident angle is preferably 10 to 80 degrees, more preferably 20 to 60 degrees, and particularly preferably 30 to 50 degrees.

The irradiation time is preferably 1 to 60 minutes, more preferably 1 to 10 minutes.

When patterning is required, a method of irradiating light using a photomask as many times as necessary for pattern formation or a method of writing a pattern by laser scanning can be employed.

[ adhesive layer ]

The laminate of the present invention may have an adhesive layer between the optical film and the λ/4 plate.

In this specification, the term "adhesive layer" is a concept including "adhesive layer". Here, "adhesion" is a type of adhesion, and means that even after a certain period of time has elapsed after the adhesion to an adherend, the change in the force of adhesion (adhesive force) is small, and the peeling can be performed as needed. The term "adhesion" is a concept including the above-described "adhesion", and simply means a state in which objects to be adhered are integrally adhered to each other.

The adhesive layer preferably comprises an adhesive. Examples of the adhesive include rubber adhesives, (meth) acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, and cellulose adhesives.

Among these, acrylic adhesives (pressure-sensitive adhesives) are preferred from the viewpoint of transparency, weather resistance, heat resistance, and the like.

The adhesive layer can be formed, for example, by the following method: a method in which a solution of an adhesive (adhesive composition) is applied to a release sheet, dried, and then transferred to the surface of a transparent resin layer; a method of directly applying a solution of the binder to the surface of the transparent resin layer and drying the solution.

The binder solution (binder composition) is prepared by dissolving or dispersing about 10 to 40 mass% of the binder in a solvent such as toluene or ethyl acetate.

The coating method can be roll coating such as reverse coating or gravure coating, spin coating, screen coating, spray coating, dipping, spray coating, or the like.

The adhesive composition may contain the antistatic agent, and may contain other components (for example, a curing agent, a coupling agent, and the like).

Examples of the material constituting the release sheet include synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate; a rubber sheet; paper; cloth; non-woven fabrics; a wire mesh; a foamed sheet; a suitable sheet such as a metal foil.

In the present invention, the thickness of any adhesive layer is not particularly limited, but is preferably 3 to 50 μm, more preferably 4 to 40 μm, and particularly preferably 5 to 30 μm.

[ protective layer ]

The optical film in the laminate of the present invention may have a protective layer. When the optical film has a protective layer, the protective layer is disposed on the λ/4 plate side of the light absorption anisotropic film.

The protective layer is also called a barrier layer or a gas barrier layer (oxygen barrier layer), and has a function of protecting the light absorbing anisotropic film from a gas such as oxygen in the atmosphere, moisture, or a compound contained in an adjacent layer.

As the protective layer, reference can be made to the descriptions of paragraphs [0014] to [0054] of Japanese patent application laid-open No. 2014-159124, paragraphs [0042] to [0075] of Japanese patent application laid-open No. 2017-121721, paragraphs [0045] to [0054] of Japanese patent application laid-open No. 2017-115076, paragraphs [0010] to [0061] of Japanese patent application laid-open No. 2012-213938, and paragraphs [0021] to [0031] of Japanese patent application laid-open No. 2005-16994.

The laminate of the present invention is obtained by laminating the respective members in a desired order by a known method, and the production method thereof is not particularly limited.