WO2022202268A1

WO2022202268A1 - Viewing angle control system, image display device, optically anisotropic layer, and laminate

Info

Publication number: WO2022202268A1
Application number: PCT/JP2022/009847
Authority: WO
Inventors: 直良山田; 伸一吉成; 晋也渡邉
Original assignee: 富士フイルム株式会社
Priority date: 2021-03-26
Filing date: 2022-03-08
Publication date: 2022-09-29
Also published as: JPWO2022202268A1

Abstract

The present invention provides: a viewing angle control system which, when applied to a display device requiring viewing angle control, has higher viewing angle controllability for an azimuth angle such as that for making visual recognition impossible from a specific azimuth angle, etc., and has excellent front direction transmittance; an image display device; a light absorption anisotropic layer; and a laminate. This viewing angle control system has a polarizer and a first light absorption anisotropic layer, wherein: the polarizer has an absorption axis in the in-plane direction, and an angle formed between the absorption axis of the polarizer and the orientation having the lowest transmittance with respect to linearly polarized light in the in-plane direction of the first light absorption anisotropic layer is at least 0° but less than 45°; the first light absorption anisotropic layer has, along the thickness direction, a plurality of regions having absorption axes inclined with respect to the direction normal to the surface of the first light absorption anisotropic layer, and the inclination angles of the absorption axes in the plurality of regions with respect to the direction normal to the surface of the first absorption anisotropic layer differ from each other.

Description

viewing angle control system, image display device, optically anisotropic layer, laminate

The present invention relates to a viewing angle control system, an image display device, an optically anisotropic layer, and a laminate.

Image display devices are used in a variety of situations, and depending on their use, it may be necessary to prevent others from looking into them or to control viewing angles, such as the reflection of images. For example, when using an in-vehicle display such as a car navigation system, there is a problem that the light emitted from the display screen is reflected on the windshield, window glass, etc., and interferes with driving.

Patent Document 1 discloses a film in which a polarizer having an absorption axis in the in-plane direction and a light absorption anisotropic layer in which a dichroic material is vertically aligned is combined, and a display device provided with this film. describes that a good dark state is achieved in any orientation.

JP-A-2001-242320

On the other hand, in recent years, there has been a demand for more strict control of the viewing angle.
The present inventors applied the film described in Patent Document 1 to a display device and studied its viewing angle controllability. It was not always possible to respond to the recent demand level. In particular, there is a strong tendency for the above reflection to occur in oblique directions with respect to the display surface of the display device.
In addition, the viewing angle control system is also required to have excellent transmittance in the front direction from the viewpoint of image visibility of the display device to which it is applied.

INDUSTRIAL APPLICABILITY The present invention provides a viewing angle control system that, when applied to a display device that requires viewing angle control, has higher viewing angle controllability with respect to azimuth angles, such as making it invisible from a specific azimuth angle, and excellent transmittance in the front direction. The task is to provide
Another object of the present invention is to provide an image display device.
Another object of the present invention is to provide a light absorption anisotropic layer that can constitute the viewing angle control system by combining with a polarizer.
Furthermore, another object of the present invention is to provide a laminate including the light absorption anisotropic layer.

The inventors have found that the above problems can be solved by the following configuration.

(1) having a polarizer and a first light absorption anisotropic layer,
The polarizer has an absorption axis in the in-plane direction,
The angle formed by the azimuth with the lowest transmittance for linearly polarized light in the in-plane direction of the first light absorption anisotropic layer and the absorption axis of the polarizer is 0° or more and less than 45°,
The first light absorption anisotropic layer has a plurality of regions along the thickness direction, each having an absorption axis tilted with respect to the normal direction of the surface of the first light absorption anisotropic layer,
A viewing angle control system in which the angles of inclination of the absorption axis with respect to the normal direction of the surface of the first light absorption anisotropic layer are different in the plurality of regions.
(2) According to (1), the inclination angles of the absorption axes of the plurality of regions with respect to the normal direction of the surface of the first light absorption anisotropic layer continuously change along the thickness direction. viewing angle control system.
(3) The viewing angle control system according to (1) or (2), wherein the first light absorption anisotropic layer contains a liquid crystal compound and a dichroic substance.
(4) The viewing angle control system according to any one of (1) to (3), further comprising a second light absorption anisotropic layer having an absorption axis parallel to the thickness direction.
(5) An image display device including the viewing angle control system according to any one of (1) to (4).
(6) The image display device according to (5), including a liquid crystal cell and a viewing angle control system arranged on the liquid crystal cell.
(7) The image display device according to (5), including a self-luminous display device and a viewing angle control system arranged on the viewing side of the self-luminous display device.
(8) A light absorption anisotropic layer,
along the thickness direction, having a plurality of regions having absorption axes inclined with respect to the normal direction of the surface of the light absorption anisotropic layer;
An anisotropic light absorption layer in which the angles of inclination of the absorption axes with respect to the normal direction of the surface of the anisotropic light absorption layer are different in a plurality of regions.
(9) The light absorption according to (8), wherein the angles of inclination of the absorption axes of the plurality of regions with respect to the normal direction of the surface of the light absorption anisotropic layer continuously change along the thickness direction. anisotropic layer.
(10) The anisotropic light absorption layer according to (8) or (9), wherein the anisotropic light absorption layer contains a liquid crystal compound and a dichroic substance.
(11) a light absorption anisotropic layer according to any one of (8) to (10);
and a light absorption anisotropic layer having an absorption axis parallel to the thickness direction.

According to the present invention, when applied to a display device that requires viewing angle control, viewing angle control with higher viewing angle controllability with respect to azimuth angles, such as making it invisible from a specific azimuth angle, and superior transmittance in the front direction. system can be provided.
Further, according to the present invention, an image display device can be provided.
Further, according to the present invention, it is possible to provide a light absorption anisotropic layer that can constitute the viewing angle control system by combining with a polarizer.
Furthermore, according to the present invention, it is possible to provide a laminate including the light absorption anisotropic layer.

1 is a sectional view conceptually showing an example of a viewing angle control system of the present invention; FIG. 2 is a plan view of the viewing angle control system shown in FIG. 1; FIG. FIG. 4 is a diagram for explaining a method of obtaining an evaluation sample in an example; FIG. 4 is a diagram for explaining a method of measuring the direction of the absorption axis in an evaluation sample; It is a sectional view for explaining the pasting state of a light absorption anisotropic film. FIG. 4 is a diagram for explaining a method of evaluating reflection;

The present invention will be described in detail below.
The description of the constituent elements described below may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
In this specification, a numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits.
Moreover, in this specification, parallel does not mean parallel in a strict sense, but means a range of ±5° from parallel.
In this specification, orthogonal does not mean orthogonal in a strict sense, but means a range of ±5° from orthogonal.

In the present specification, "(meth)acryl" is used to mean "one or both of acrylic and methacrylic". "(Meth)acryloyl" is used in the sense of "one or both of acryloyl and methacryloyl".
The bonding direction of the divalent group (e.g., -COO-) described herein is not particularly limited. For example, when L in XLY is -COO-, If the position where *1 is attached and *2 is the position where the good too.

A feature of the viewing angle control system of the present invention is that the angle formed by the absorption axis of the polarizer and the direction having the lowest transmittance for linearly polarized light in the in-plane direction of the first light absorption anisotropic layer is a predetermined angle. point (hereinafter also referred to as “characteristic point 1”), and a point in which the first light absorption anisotropic layer has a plurality of regions with different absorption axis tilt angles along the thickness direction (hereinafter, “characteristic point 1”). Also referred to as “point 2”).
By satisfying feature point 1, the frontal transmittance of the viewing angle control system is excellent. Further, by satisfying characteristic point 2, when the viewing angle control system is viewed from various azimuth angles, the absorption axis of the polarizer and any of the plurality of absorption axes included in the first light absorption anisotropic layer intersect. Therefore, by controlling the tilt angles of the plurality of absorption axes included in the first light absorption anisotropic layer, the center of the viewing angle (the most visible position) can be freely changed. .

FIG. 1 shows a sectional view conceptually showing an example of the viewing angle control system of the present invention. FIG. 2 shows a plan view of the viewing angle control system shown in FIG. A plan view is a view of the viewing angle control system 10 viewed from above in FIG. 1 is a cross-sectional view taken along line A--A in FIG.
In FIG. 1, direction X and direction Z indicate directions of two coordinate axes orthogonal to each other on the viewing plane. Direction Z is parallel to the thickness direction of viewing angle control system 10 .
In FIG. 2, direction X and direction Y indicate directions of two coordinate axes orthogonal to each other on the viewing plane.
The viewing angle control system 10 has a polarizer 12 and a first light absorption anisotropic layer 14 . The first light absorption anisotropic layer 14 contains a dichroic substance 16 and a liquid crystal compound (not shown).
As shown in FIGS. 1 and 2, when the first light absorption anisotropic layer 14 is observed from the normal direction of its surface, the dichroic substances 16 are arranged in a certain direction. More specifically, the direction of projection of the major axis direction of the dichroic substance 16 onto the surface of the first light absorption anisotropic layer 14 is parallel to the X-axis direction (horizontal direction on the paper surface).
Therefore, as shown in FIG. 2, the X-axis direction (horizontal direction of the paper surface) corresponds to the direction in which the transmittance for linearly polarized light is the lowest in the in-plane direction of the first light absorption anisotropic layer 14 . That is, the direction of the white arrow (horizontal direction of the paper surface) shown in FIG. 2 is the direction D (hereinafter referred to as the “specific Also referred to as “direction D”).
On the other hand, as indicated by the black arrow in FIG. 1, the absorption axis A of the polarizer 12 is arranged parallel to the X-axis direction (horizontal direction on the paper surface).
Therefore, the specific orientation D and the absorption axis A of the polarizer 12 are arranged in parallel. By arranging the specific orientation D and the absorption axis A of the polarizer 12 in parallel, the viewing angle control system has excellent transmittance in the front direction.

1 and 2 show an aspect in which the specific orientation D and the absorption axis A of the polarizer 12 are parallel (0°), but in the present invention, the specific orientation and the absorption axis of the polarizer The angle should be 0° or more and less than 45°. Among them, the angle formed by the specific orientation and the absorption axis of the polarizer is preferably 0° or more and less than 10°, more preferably 0°, because the transmittance in the front direction of the viewing angle control system is more excellent.
The method for measuring the specific orientation D is as follows.
The first light absorption anisotropic layer 14 is peeled off from the polarizer 12, and the peeled first light absorption anisotropic layer 14 is placed on a rotating stage of a polarizing microscope. Next, with the linear polarizer of the polarizing microscope set and the analyzer removed, the rotating stage is rotated to find the direction with the lowest brightness. It is estimated that the specific orientation D of the first light absorption anisotropic layer 14 and the absorption axis of the polarizer of the polarizing microscope are orthogonal to each other when the luminance is the lowest. is determined.

Further, as shown in FIG. 1, the first light absorption anisotropic layer 14 has three regions 14A to 14C. The long axis direction of the dichroic substance 16 is tilted. The inclination of the long axis direction of the dichroic substance 16 with respect to the normal direction of the surface of the first light absorption anisotropic layer 14 in each region continuously decreases along the thickness direction as the distance from the polarizer 12 increases. .
In the first light absorption anisotropic layer 14, the direction parallel to the long axis direction of the dichroic substance 16 is the direction of the absorption axis, so the absorption axis is located in the direction of the white arrow in each region. do. Therefore, in FIG. 1, the angle of inclination of the absorption axis with respect to the normal direction of the surface of the first light absorption anisotropic layer 14 in each of the three regions 14A to 14C is different, and the first light absorption anisotropic layer The inclination angle of the absorption axis with respect to the normal direction of the 14 surface decreases continuously along the thickness direction as the distance from the polarizer 12 increases.

In FIG. 1, the three regions have described the mode in which the absorption axes are different in inclination angle with respect to the normal direction of the surface of the first optical absorption anisotropic layer 14, but in the present invention, the first optical absorption anisotropy It is sufficient that the anisotropic layer has a plurality of (two or more) regions having absorption axes with different tilt angles with respect to the normal direction of the surface of the first light absorption anisotropic layer.
The number of regions is not particularly limited, and may be two or more, preferably three or more, and more preferably five or more. It is also preferable that the inclination angle of the absorption axis with respect to the normal direction of the surface of the first light absorption anisotropic layer 14 changes continuously along the thickness direction. In this case, it can be divided into an infinite number of regions along the thickness direction. are different from each other. Such an aspect corresponds to a so-called hybrid orientation aspect of the dichroic substance.
A method for measuring the direction of the absorption axis in each region is not particularly limited, and known methods can be used. For example, as shown in FIG. 1, by preparing a cross section of the viewing angle control system and observing the cross section with a polarizing microscope while rotating the first light absorption anisotropic layer in the measurement sample, the light absorption anisotropic The direction of the absorption axis in each region arranged in the thickness direction in the organic layer can be determined.
When obtaining the cross section of the viewing angle control system, the viewing angle control system is measured along a direction parallel to a plane including the central axis of transmittance of the viewing angle control system and the normal direction of the surface of the first light absorption anisotropic layer. It is preferable to disconnect the system.
The transmittance central axis is defined as the transmittance central axis in the direction in which the transmittance is the highest when the transmittance is measured by changing the tilt angle and the tilt direction with respect to the normal direction to the surface of the first light absorption anisotropic layer. . More specifically, AxoScan OPMF-1 (manufactured by Optoscience) is used to measure the transmittance of the first light absorption anisotropic layer for P-polarized light with a wavelength of 550 nm. More specifically, during the measurement, the azimuth angle at which the transmittance central axis is tilted is first searched, and then the normal direction of the first light absorption anisotropic layer along that azimuth angle is included. The polar angle, which is the angle with respect to the normal direction of the surface of the first light absorption anisotropic layer, within the plane (the plane including the transmittance center axis and perpendicular to the layer surface) is changed in increments of 5° from 0 to 60°. Meanwhile, P-polarized light with a wavelength of 550 nm is incident, and the transmittance of the first light absorption anisotropic layer is measured. As a result, the direction with the highest transmittance is defined as the center axis of transmittance.

In addition, FIG. 1 describes a mode in which the inclination angle of each absorption axis in each region with respect to the normal direction of the surface of the first light absorption anisotropic layer 14 continuously changes along the thickness direction. However, the invention is not limited to this aspect.
For example, the inclination angle of each absorption axis in each region with respect to the normal direction of the surface of the first light absorption anisotropic layer 14 may change discontinuously along the thickness direction.
In addition, the inclination angle of each absorption axis in each region with respect to the normal direction of the surface of the first light absorption anisotropic layer is not particularly limited. ° is preferred, and 50 to 80° is more preferred.

In FIG. 1, the directions (orientation of the absorption axes in the in-plane direction) obtained by orthographically projecting the absorption axes of the respective regions onto the surface of the first light absorption anisotropic layer 14 are all the same direction. , the invention is not limited to this embodiment.
The same direction is not limited to being exactly the same, but also includes the case where the angle formed by the directions obtained by orthogonally projecting the respective absorption axes in each region onto the surface of the first light absorption anisotropic layer 14 is within 5°. .
If the angle formed by the azimuth with the lowest transmittance for linearly polarized light in the in-plane direction of the first light absorption anisotropic layer and the absorption axis of the polarizer is 0° or more and less than 45°, in each region The orthogonal projection of each absorption axis onto the surface of the first light absorption anisotropic layer (orientation in the in-plane direction of the absorption axis) may be different.

In addition, although FIG. 1 shows an embodiment in which the viewing angle control system includes only one first light absorption anisotropic layer 14, the present invention is not limited to this embodiment, and the viewing angle control system includes a plurality of first light An absorption anisotropic layer may be included.

In addition, as in the first optical absorption anisotropic layer 14 shown in FIGS. It can be produced by so-called hybrid orientation of the liquid crystal compound (not shown) in the layer 14 . When the liquid crystal compound in the first light absorption anisotropic layer 14 is hybrid-aligned, the dichroic substance 16 in the first light absorption anisotropic layer 14 is aligned along the alignment direction of the liquid crystal compound. In other words, the dichroic substance also undergoes hybrid orientation. Therefore, as shown in FIGS. 1 and 2, as the dichroic substance 16 moves away from the polarizer 12, the longitudinal direction of the dichroic substance 16 and the normal direction of the surface of the first light absorption anisotropic layer 14 The angle to make becomes smaller continuously.
In this specification, the hybrid alignment of the liquid crystal compound means an alignment in which the tilt angle of the liquid crystal compound changes continuously from one surface to the other surface, and hybrid alignment of a dichroic substance. is an orientation in which the tilt angle of a dichroic material changes continuously from one surface to the other.

Techniques for aligning a dichroic substance in a desired manner include a technique for producing a polarizer using a dichroic material and a technique for producing a guest-host liquid crystal cell. For example, the method for producing a dichroic polarizing element described in JP-A-11-305036 and JP-A-2002-090526, and the guests described in JP-A-2002-099388 and JP-A-2016-027387 The technique used in the manufacturing method of the host-type liquid crystal display device can also be used in manufacturing the first light absorption anisotropic layer used in the present invention.

In order to prevent the light absorption properties of the first light absorption anisotropic layer used in the present invention from varying depending on the usage environment, it is preferable to fix the orientation of the dichroic substance by forming chemical bonds. For example, the orientation can be fixed by proceeding with the polymerization of the host liquid crystal, the dichroic substance, or the optionally added polymerizable component.

In addition, by infiltrating the dichroic substance into the polymer film and orienting the dichroic substance along the orientation of the polymer molecules in the polymer film, the light absorption required for the first light absorption anisotropic layer can be achieved. A polymer film can be produced that satisfies the properties.

Also, the first light absorption anisotropic layer may be produced by laminating a plurality of light absorption anisotropic layers containing a dichroic substance and having absorption axes with different inclination angles.

Each member included in the viewing angle control system will be described in detail below.

<Polarizer>
The polarizer used in the present invention is not particularly limited as long as it has an absorption axis in the in-plane direction, and conventionally known polarizers can be used.

Examples of polarizers include iodine-based polarizers, dye-based polarizers using dichroic dyes, and polyene-based polarizers. Iodine-based polarizers and dye-based polarizers include coating-type polarizers and stretching-type polarizers, and both can be applied. As a coated polarizer, a polarizer in which a dichroic organic dye is oriented using the orientation of a liquid crystal compound is preferable. A polarizer made by
In addition, as a method of obtaining a polarizer by stretching and dyeing a laminated film in which a polyvinyl alcohol layer is formed on a substrate, there are disclosed in Japanese Patent Nos. 5048120, 5143918, 5048120, and Methods described in Japanese Patent No. 4691205, Japanese Patent No. 4751481, and Japanese Patent No. 4751486 can be mentioned, and known techniques relating to these polarizers can also be preferably used.

Among them, polyvinyl alcohol-based resins (polymers containing —CH ₂ —CHOH— as repeating units, particularly polyvinyl alcohol and ethylene-vinyl alcohol copolymers are selected from the group consisting of polyvinyl alcohol resins, which are readily available and excellent in the degree of polarization. It is preferable that the polarizer includes at least one

Although the thickness of the polarizer is not particularly limited, it is preferably 3 to 60 μm, more preferably 5 to 20 μm, even more preferably 5 to 10 μm.

<First light absorption anisotropic layer>
As described above, the first light absorption anisotropic layer has a plurality of regions along the thickness direction, which have absorption axes tilted with respect to the normal direction of the surface of the first light absorption anisotropic layer.
The material contained in the first light absorption anisotropic layer is not particularly limited as long as it exhibits the properties described above, but the first light absorption anisotropic layer preferably contains a dichroic substance.
This first light absorption anisotropic layer can constitute the above-described viewing angle control system by combining with a polarizer.

(Dichroic substance)
In the present invention, a dichroic substance means a dye that absorbs differently depending on the direction. The dichroic substance may be polymerized in the first light absorption anisotropic layer.

The dichroic substance is not particularly limited, and includes visible light absorbing substances (dichroic dyes), luminescent substances (fluorescent substances, phosphorescent substances), ultraviolet absorbing substances, infrared absorbing substances, nonlinear optical substances, carbon nanotubes, and inorganic Substances (for example, quantum rods) can be used, and conventionally known dichroic substances (dichroic dyes) can be used.
Specifically, [0067] to [0071] paragraphs of JP-A-2013-228706, [0008] to [0026] paragraphs of JP-A-2013-227532, [0008] of JP-A-2013-209367 ~ [0015] paragraph, JP 2013-14883 [0045] ~ [0058] paragraph, JP 2013-109090 [0012] ~ [0029] paragraph, JP 2013-101328 [0009 ] to [0017] paragraphs, [0051] to [0065] paragraphs of JP-A-2013-037353, [0049]-[0073] paragraphs of JP-A-2012-063387, [ 0016] to [0018] paragraphs, [0009] to [0011] paragraphs of JP-A-2001-133630, [0030]-[0169] of JP-A-2011-215337, [ 0021] to [0075] paragraphs, [0011] to [0025] paragraphs of JP-A-2010-215846, [0017] to [0069] paragraphs of JP-A-2011-048311, JP-A-2011-213610 [0013] to [0133] paragraphs, [0074] to [0246] paragraphs of JP-A-2011-237513, [0005] to [0051] paragraphs of JP-A-2016-006502, [ 0005] to [0041] paragraphs, [0008] to [0062] paragraphs of WO2016/136561, [0014] to [0033] paragraphs of WO2017/154835, [0014] of WO2017/154695 ] to [0033] paragraphs, [0013] to [0037] paragraphs of WO 2017/195833, and [0014] to [0034] paragraphs of WO 2018/164252, etc. be done.

In the present invention, two or more dichroic substances may be used in combination. and at least one dichroic substance having a maximum absorption wavelength in the wavelength range of 500 nm or more and less than 700 nm.

As will be described later, the first light absorption anisotropic layer can be formed using the composition for forming the first light absorption anisotropic layer. In the composition for forming the first light absorption anisotropic layer, the dichroic substance may have a crosslinkable group. When the dichroic substance has a crosslinkable group, when forming the first light absorption anisotropic layer using the composition for forming the first light absorption anisotropic layer, the dichroic substance in a predetermined orientation state can be immobilized.
Specific examples of the crosslinkable group include (meth)acryloyl groups, epoxy groups, oxetanyl groups, and styryl groups, among which (meth)acryloyl groups are preferred.

The content of the dichroic substance in the first light absorption anisotropic layer is not particularly limited, but at least one of superior transmittance in the front direction of the viewing angle control system and superior viewing angle controllability. (hereinafter also simply referred to as "the point where the effect of the present invention is more excellent"), it is preferably 1 to 50% by mass, and 10 to 25% by mass is more preferred.

(liquid crystal compound)
The first light absorption anisotropic layer preferably contains a liquid crystal compound. This makes it possible to orient the dichroic substance with a higher degree of orientation while suppressing precipitation of the dichroic substance.
As the liquid crystal compound, both a polymer liquid crystal compound and a low-molecular liquid crystal compound can be used, and a polymer liquid crystal compound is preferable because the degree of orientation can be increased. Further, as the liquid crystal compound, a high-molecular liquid crystal compound and a low-molecular liquid crystal compound may be used in combination.
Here, the term "polymeric liquid crystal compound" refers to a liquid crystal compound having repeating units in its chemical structure.
Further, the term "low-molecular-weight liquid crystal compound" refers to a liquid crystal compound having no repeating unit in its chemical structure.
Examples of the polymer liquid crystal compound include thermotropic liquid crystalline polymers described in JP-A-2011-237513, and high molecular weight compounds described in paragraphs [0012] to [0042] of International Publication No. 2018/199096. Examples include molecular liquid crystal compounds.
Examples of low-molecular-weight liquid crystal compounds include liquid crystal compounds described in paragraphs [0072] to [0088] of JP-A-2013-228706, among which liquid crystal compounds exhibiting smectic properties are preferred.

In the liquid crystal compound, a repeating unit represented by the following formula (1) (hereinafter also abbreviated as “repeating unit (1)”) is used because the degree of orientation of the obtained first light absorption anisotropic layer is higher. It is preferably a polymer liquid crystal compound containing.

In the above formula (1), P1 represents the main chain of the repeating unit, L1 represents a single bond or a divalent linking group, SP1 represents a spacer group, M1 represents a mesogenic group, and T1 represents a terminal group. .

Specific examples of the main chain of the repeating unit represented by P1 include groups represented by the following formulas (P1-A) to (P1-D). A group represented by the following formula (P1-A) is preferable in terms of diversity and ease of handling.

In the above formulas (P1-A) to (P1-D), "*" represents the bonding position with L1 in the above formula (1).
In the above formulas (P1-A) to (P1-D), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, Alternatively, it represents an alkoxy group having 1 to 10 carbon atoms. The alkyl group may be a linear or branched alkyl group, or may be an alkyl group having a cyclic structure (cycloalkyl group). Moreover, the number of carbon atoms in the alkyl group is preferably 1 to 5.
The group represented by the above formula (P1-A) is preferably one unit of the partial structure of the poly(meth)acrylic acid ester obtained by polymerization of the (meth)acrylic acid ester.
The group represented by the above formula (P1-B) is preferably an ethylene glycol unit formed by ring-opening polymerization of an epoxy group of a compound having an epoxy group.
The group represented by the above formula (P1-C) is preferably a propylene glycol unit formed by ring-opening polymerization of an oxetane group of a compound having an oxetane group.
The group represented by formula (P1-D) is preferably a siloxane unit of polysiloxane obtained by condensation polymerization of a compound having at least one of an alkoxysilyl group and a silanol group. Here, the compound having at least one of an alkoxysilyl group and a silanol group includes a compound having a group represented by the formula SiR ¹⁴ (OR ¹⁵ ) ₂ —. In the formula, R ¹⁴ has the same definition as R ¹⁴ in (P1-D), and each of a plurality of R ¹⁵ independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

In formula (1) above, L1 is a single bond or a divalent linking group.
Divalent linking groups represented by L1 include -C(O)O-, -O-, -S-, -C(O)NR ³ -, -SO ₂ -, and -NR ³ R ⁴ -. is mentioned. In the formula, R ³ and R ⁴ each independently represent a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms.
When P1 is a group represented by formula (P1-A), L1 is represented by -C(O)O- because the degree of orientation of the first light absorption anisotropic layer is higher. groups are preferred.
When P1 is a group represented by formulas (P1-B) to (P1-D), L1 is preferably a single bond because the degree of orientation of the first light absorption anisotropic layer becomes higher.

In the above formula (1), the spacer group represented by SP1 is composed of an oxyethylene structure, an oxypropylene structure, a polysiloxane structure and an alkylene fluoride structure in view of the ease of exhibiting liquid crystallinity and the availability of raw materials. It preferably contains at least one structure selected from the group.
Here, the oxyethylene structure represented by SP1 is preferably a group represented by *--(CH ₂ --CH ₂ O) _n1 --*. In the formula, n1 represents an integer of 1 to 20, * represents the bonding position with L1 or M1 in the above formula (1). n1 is preferably an integer of 2 to 10, more preferably an integer of 2 to 4, and more preferably 3, in order to increase the degree of orientation of the first light absorption anisotropic layer. preferable.
In addition, the oxypropylene structure represented by SP1 has a higher degree of orientation of the first light absorption anisotropic layer, so the group represented by *-(CH(CH ₃ )-CH ₂ O) _n2 -* is preferable. In the formula, n2 represents an integer of 1 to 3, and * represents the bonding position with L1 or M1.
Further, the polysiloxane structure represented by SP1 is preferably a group represented by *-(Si(CH ₃ ) ₂ -O) _n3 -* because the degree of orientation of the first light absorption anisotropic layer is higher. . In the formula, n3 represents an integer of 6 to 10, * represents the bonding position with L1 or M1.
Further, the alkylene fluoride structure represented by SP1 is preferably a group represented by *-(CF ₂ -CF ₂ ) _n4 -* because the degree of orientation of the first light absorption anisotropic layer is higher. In the formula, n4 represents an integer of 6 to 10, * represents the bonding position with L1 or M1.

In the above formula (1), the mesogenic group represented by M1 is a group showing the main skeleton of the liquid crystal molecule that contributes to liquid crystal formation. Liquid crystal molecules exhibit liquid crystallinity, which is an intermediate state (mesophase) between a crystalline state and an isotropic liquid state. There are no particular restrictions on the mesogenic group. ed., Liquid Crystal Handbook (Maruzen, 2000), especially the description in Chapter 3.
As the mesogenic group, for example, a group having at least one cyclic structure selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups is preferred.
The mesogenic group preferably has an aromatic hydrocarbon group, more preferably 2 to 4 aromatic hydrocarbon groups, from the viewpoint that the degree of orientation of the first light absorption anisotropic layer is higher, More preferably it has 3 aromatic hydrocarbon groups.

As the mesogenic group, the following formula (M1-A ) or a group represented by the following formula (M1-B) is preferable, and a group represented by the formula (M1-B) is more preferable.

In formula (M1-A), A1 is a divalent group selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups and alicyclic groups. These groups may be substituted with alkyl groups, fluorinated alkyl groups, alkoxy groups or substituents.
The divalent group represented by A1 is preferably a 4- to 6-membered ring. Also, the divalent group represented by A1 may be monocyclic or condensed.
* represents the binding position with SP1 or T1.

The divalent aromatic hydrocarbon group represented by A1 includes a phenylene group, a naphthylene group, a fluorene-diyl group, an anthracene-diyl group and a tetracene-diyl group. A phenylene group or a naphthylene group is preferable, and a phenylene group is more preferable, from the viewpoint of properties and the like.

The divalent heterocyclic group represented by A1 may be either aromatic or non-aromatic, but is preferably a divalent aromatic heterocyclic group from the viewpoint of further improving the degree of orientation. .
Atoms other than carbon constituting the divalent aromatic heterocyclic group include a nitrogen atom, a sulfur atom and an oxygen atom. When the aromatic heterocyclic group has a plurality of non-carbon ring-constituting atoms, these may be the same or different.
Specific examples of divalent aromatic heterocyclic groups include, for example, pyridylene group (pyridine-diyl group), pyridazine-diyl group, imidazole-diyl group, thienylene (thiophene-diyl group), quinolylene group (quinoline-diyl group ), isoquinolylene group (isoquinoline-diyl group), oxazole-diyl group, thiazole-diyl group, oxadiazole-diyl group, benzothiazole-diyl group, benzothiadiazole-diyl group, phthalimide-diyl group, thienothiazole-diyl group , thiazolothiazole-diyl group, thienothiophene-diyl group, and thienooxazole-diyl group.

Specific examples of the divalent alicyclic group represented by A1 include a cyclopentylene group and a cyclohexylene group.

In formula (M1-A), a1 represents an integer of 1-10. When a1 is 2 or more, multiple A1s may be the same or different.

In formula (M1-B), A2 and A3 are each independently a divalent group selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups and alicyclic groups. Specific examples and preferred embodiments of A2 and A3 are the same as those of A1 in formula (M1-A), so description thereof is omitted.
In formula (M1-B), a2 represents an integer of 1 to 10, and when a2 is 2 or more, multiple A2 may be the same or different, and multiple A3 may be the same or different. A plurality of LA1 may be the same or different. a2 is preferably an integer of 2 or more, more preferably 2, from the viewpoint that the degree of orientation of the first light absorption anisotropic layer becomes higher.
In formula (M1-B), when a2 is 1, LA1 is a divalent linking group. When a2 is 2 or more, each of the plurality of LA1 is independently a single bond or a divalent linking group, and at least one of the plurality of LA1 is a divalent linking group. When a2 is 2, it is preferable that one of the two LA1 is a divalent linking group and the other is a single bond because the degree of orientation of the first light absorption anisotropic layer is higher. .

In formula (M1-B), the divalent linking group represented by LA1 includes -O-, -(CH ₂ ) _g -, -(CF ₂ ) _g -, -Si(CH ₃ ) ₂ -, -( Si(CH ₃ ) ₂ O) _g -, -(OSi(CH ₃ ) ₂ ) _g - (g represents an integer of 1 to 10), -N(Z)-, -C(Z)=C( Z')-, -C(Z)=N-, -C(Z) ₂ -C(Z') ₂ -, -C(O)-, -OC(O)-, -OC(O) O-, -N(Z)C(O)-, -C(Z)=C(Z')-C(O)O-, -C(Z)=N-, -C(Z)=C( Z')-C(O)N(Z'')-, -C(Z)=C(Z')-C(O)-S-, -C(Z)=N-N=C(Z') - (Z, Z', Z" each independently represent a hydrogen atom, a C1-C4 alkyl group, a cycloalkyl group, an aryl group, a cyano group, or a halogen atom.), -C≡C-, - N=N-, -S-, -S(O)-, -S(O)(O)-, -(O)S(O)O-, -O(O)S(O)O-, and , -SC(O), and the like. Of these, -C(O)O- is preferred because the degree of orientation of the light absorption anisotropic layer is higher. LA1 may be a group in which two or more of these groups are combined.

Specific examples of M1 include the following structures. In addition, in the following specific examples, "Ac" represents an acetyl group.

In the above formula (1), the terminal group represented by T1 includes a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms. 1 to 10 alkylthio group, 1 to 10 carbon alkoxycarbonyloxy group, 1 to 10 carbon alkoxycarbonyl group (ROC(O)-: R is an alkyl group), 1 to 10 carbon acyloxy group, carbon 1 to 10 acylamino group, 1 to 10 carbon atoms alkoxycarbonylamino group, 1 to 10 carbon atoms sulfonylamino group, 1 to 10 carbon atoms sulfamoyl group, 1 to 10 carbon atoms carbamoyl group, 1 carbon atom 10 to 10 sulfinyl groups, ureido groups with 1 to 10 carbon atoms, and (meth)acryloyloxy group-containing groups. Examples of the (meth)acryloyloxy group-containing group include -LA (L represents a single bond or a linking group. Specific examples of the linking group are the same as L1 and SP1 described above. A is (meth) represents an acryloyloxy group).

T1 is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 5 carbon atoms, and even more preferably a methoxy group, since the degree of orientation of the first light absorption anisotropic layer becomes higher.
These terminal groups may be further substituted with these groups or polymerizable groups described in JP-A-2010-244038.

T1 is preferably a polymerizable group from the viewpoint that the adhesiveness to the adjacent layer can be improved and the cohesive force of the film can be improved.
The polymerizable group is not particularly limited, but is preferably a polymerizable group capable of radical polymerization or cationic polymerization.
As the radically polymerizable group, generally known radically polymerizable groups can be used, and acryloyl groups and methacryloyl groups are preferred. In this case, an acryloyl group is generally known to have a high polymerization rate, and an acryloyl group is preferred from the viewpoint of improving productivity, but a methacryloyl group can also be used as the polymerizable group.
As the cationically polymerizable group, generally known cationically polymerizable groups can be used. Specifically, alicyclic ether groups, cyclic acetal groups, cyclic lactone groups, cyclic thioether groups, spiroorthoester groups, and , a vinyloxy group, and the like. Among them, an alicyclic ether group or a vinyloxy group is preferable, and an epoxy group, an oxetanyl group or a vinyloxy group is preferable.

The weight-average molecular weight (Mw) of the polymer liquid crystal compound containing the repeating unit represented by the above formula (1) is preferably from 1000 to 500000, more preferably from 2000 to 300,000 is more preferred. If the Mw of the polymer liquid crystal compound is within the above range, the polymer liquid crystal compound can be easily handled.
In particular, the weight average molecular weight (Mw) of the polymer liquid crystal compound is preferably 10,000 or more, more preferably 10,000 to 300,000, from the viewpoint of suppressing cracks during coating.
In view of the temperature latitude of the degree of orientation, the weight average molecular weight (Mw) of the polymer liquid crystal compound is preferably less than 10,000, more preferably 2,000 or more and less than 10,000.
Here, the weight average molecular weight and number average molecular weight in the present invention are values measured by a gel permeation chromatography (GPC) method.
・Solvent (eluent): N-methylpyrrolidone ・Device name: TOSOH HLC-8220GPC
・Column: 3 TOSOH TSKgelSuperAWM-H (6mm×15cm) are connected and used ・Column temperature: 25℃
・Sample concentration: 0.1% by mass
・Flow rate: 0.35 mL/min
・ Calibration curve: TOSOH TSK standard polystyrene Mw = 2800000 to 1050 (Mw / Mn = 1.03 to 1.06) using a calibration curve from 7 samples

When the first light absorption anisotropic layer contains a liquid crystal compound, the content of the liquid crystal compound is 50 to 99% with respect to the total mass of the first light absorption anisotropic layer, since the effect of the present invention is more excellent. % by mass is preferable, and 75 to 90% by mass is more preferable.

(other ingredients)
The first light absorption anisotropic layer may contain components other than the components described above. Other components include, for example, vertical alignment agents and leveling agents.

(vertical alignment agent)
Vertical alignment agents include boronic acid compounds and onium salts.
A compound represented by formula (A) is preferable as the boronic acid compound.

Expression (A)

In formula (A), R ¹ and R ² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. show.
R3 represents a substituent containing a ⁽ meth)acryl group.
Specific examples of the boronic acid compound include boronic acid compounds represented by general formula (I) described in paragraphs [0023] to [0032] of JP-A-2008-225281.
As the boronic acid compound, compounds exemplified below are also preferable.

As the onium salt, the compound represented by formula (B) is preferable.

Formula (B)

In formula (B), ring A represents a quaternary ammonium ion consisting of a nitrogen-containing heterocyclic ring. X ⁻ represents an anion. L ¹ represents a divalent linking group. L2 represents a single bond or a ^divalent linking group. Y ¹ represents a divalent linking group having a 5- or 6-membered ring as a partial structure. Z represents a divalent linking group having 2 to 20 alkylene groups as a partial structure. P ¹ and P ² each independently represent a monovalent substituent having a polymerizable ethylenically unsaturated bond.
Specific examples of onium salts include onium salts described in paragraphs [0052] to [0058] of JP-A-2012-208397, and onium described in paragraphs [0024] to [0055] of JP-A-2008-026730. salts, and onium salts described in JP-A-2002-037777.

When the first light absorption anisotropic layer contains a liquid crystal compound and a vertical alignment agent, the content of the vertical alignment agent is preferably 0.1 to 400% by mass, more preferably 0.5 to 350%, based on the total mass of the liquid crystal compound. % by mass is more preferred.
The vertical alignment agents may be used alone or in combination of two or more. When two or more vertical alignment agents are used, the total amount thereof is preferably within the above range.

(leveling agent)
The first light absorption anisotropic layer may contain a leveling agent. When the composition for forming the first light absorption anisotropic layer (light absorption anisotropic layer), which will be described later, contains a leveling agent, surface roughness due to drying air applied to the surface of the first light absorption anisotropic layer is suppressed. and the dichroic material is oriented more uniformly.
The leveling agent is not particularly limited, and is preferably a leveling agent containing fluorine atoms (fluorine-based leveling agent) or a leveling agent containing silicon atoms (silicon-based leveling agent), more preferably a fluorine-based leveling agent.

Examples of fluorine-based leveling agents include fatty acid esters of polyvalent carboxylic acids in which a portion of the fatty acid is substituted with a fluoroalkyl group, and polyacrylates having fluoro substituents.

Specific examples of the leveling agent include compounds exemplified in paragraphs [0046] to [0052] of JP-A-2004-331812, and paragraphs [0038] to [0052] of JP-A-2008-257205. and the compound of

When the first light absorption anisotropic layer contains a liquid crystal compound and a leveling agent, the content of the leveling agent is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, based on the total mass of the liquid crystal compound. is more preferred.
A leveling agent may be used independently and may be used in combination of 2 or more type. When two or more leveling agents are used, the total amount thereof is preferably within the above range.

(Composition for forming first light absorption anisotropic layer)
The first light absorption anisotropic layer is preferably formed using a composition for forming a first light absorption anisotropic layer containing a dichroic substance.
In addition to the dichroic substance, the composition for forming the first light absorption anisotropic layer preferably contains a liquid crystal compound, a solvent to be described later, and the like, and may further contain other components described above. .

The dichroic substance contained in the composition for forming the first light absorption anisotropic layer includes a dichroic substance that can be contained in the first light absorption anisotropic layer.
The content of the dichroic substance with respect to the total solid weight of the composition for forming the first light absorption anisotropic layer is the same as the content of the dichroic substance with respect to the total weight of the first light absorption anisotropic layer. is preferred.
Here, "the total solid content in the composition for forming the first light absorption anisotropic layer" refers to components excluding the solvent, and specific examples of the solid content include dichroic substances, liquid crystal compounds, and Other ingredients mentioned above are included.

The liquid crystal compound and other components that may be contained in the composition for forming the first light absorption anisotropic layer are the same as the liquid crystal compound and other components that may be contained in the first light absorption anisotropic layer. be.
The contents of the liquid crystal compound and other components relative to the total solid mass of the composition for forming the first light absorption anisotropic layer are respectively the liquid crystal compound and other components relative to the total mass of the first light absorption anisotropic layer. is preferably the same as the content of the components of

From the viewpoint of workability, the composition for forming the first light absorption anisotropic layer preferably contains a solvent.
Examples of solvents include ketones, ethers, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated carbons, esters, alcohols, cellosolves, cellosolve acetates, sulfoxides, , amides, and organic solvents such as heterocyclic compounds, as well as water.
These solvents may be used singly or in combination of two or more.
Among these solvents, organic solvents are preferred, and halogenated carbons or ketones are more preferred.

When the composition for forming the first light absorption anisotropic layer contains a solvent, the content of the solvent is preferably 80 to 99% by mass with respect to the total mass of the composition for forming the first light absorption anisotropic layer. , more preferably 83 to 97% by mass, and even more preferably 85 to 95% by mass.

The composition for forming the first light absorption anisotropic layer may contain a polymerization initiator.
Although the polymerization initiator is not particularly limited, it is preferably a compound having photosensitivity, that is, a photopolymerization initiator.
As such a photopolymerization initiator, commercially available products can also be used, and Irgacure 184, Irgacure 907, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure OXE-01 and Irgacure manufactured by BASF. and OXE-02.
A polymerization initiator may be used individually by 1 type, or may use 2 or more types together.
When the composition for forming the first light absorption anisotropic layer contains a polymerization initiator, the content of the polymerization initiator is 0.00% with respect to the total solid content of the composition for forming the first light absorption anisotropic layer. 01 to 30% by mass is preferred, and 0.1 to 15% by mass is more preferred.

<Method for producing first light absorption anisotropic layer>
The method for producing the first light absorption anisotropic layer is not particularly limited, but since the degree of orientation of the obtained first light absorption anisotropic layer is higher, a dichroic substance and a liquid crystal compound are added on the alignment film. a step of forming a coating film by applying a composition for forming a first light absorption anisotropic layer containing the (hereinafter also referred to as "orientation step"), and a method (hereinafter also referred to as "this production method") in this order is preferred.
The liquid crystal component is a component containing not only the liquid crystal compound described above but also a dichroic substance having liquid crystallinity.
Each step will be described below.

(Coating film forming step)
The coating film forming step is a step of applying the composition for forming the first light absorption anisotropic layer on the alignment film to form a coating film.
The composition for forming the first light absorption anisotropic layer containing the above-described solvent is used, or the composition for forming the first light absorption anisotropic layer is heated to be a liquid such as a melt. This makes it easier to apply the composition for forming the first light absorption anisotropic layer onto the alignment film.
Examples of the method of applying the composition for forming the first light absorption anisotropic layer include a roll coating method, a gravure printing method, a spin coating method, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die Known methods such as a coating method, a spray method, and an inkjet method can be used.

(Alignment film)
The alignment film may be any film as long as it aligns the liquid crystal component that can be contained in the composition for forming the first light absorption anisotropic layer.
Rubbing treatment on the film surface of an organic compound (preferably polymer), oblique vapor deposition of an inorganic compound, formation of a layer having microgrooves, or an organic compound (eg, ω-tricosanoic acid) by the Langmuir-Blodgett method (LB film) , dioctadecylmethylammonium chloride, methyl stearate). Furthermore, an alignment film is also known in which an alignment function is produced by application of an electric field, application of a magnetic field, or irradiation of light. Among them, in the present invention, an alignment film formed by rubbing treatment is preferable from the viewpoint of ease 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 alignment uniformity.

(Orientation process)
The alignment step is a step of orienting the liquid crystal component (especially dichroic substance) contained in the coating film. In the alignment step, the dichroic substance is considered to be aligned along the liquid crystal compound aligned by the alignment film.
The orientation step may include drying. Components such as the solvent can be removed from the coating film by the drying treatment. 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 by a method of heating and/or blowing air.

The orientation step preferably includes heat treatment. As a result, the dichroic substance contained in the coating film is more oriented, and the degree of orientation of the resulting anisotropic light absorption layer is increased.
The heat treatment is preferably from 10 to 250° C., more preferably from 25 to 190° C., from the viewpoint of suitability for production. Also, the heating time is preferably 1 to 300 seconds, more preferably 1 to 60 seconds.

The orientation step may have a cooling treatment performed after the heat treatment. The cooling process is a process of cooling the coated film after heating to about room temperature (20 to 25° C.). Thereby, the orientation of the dichroic substance contained in the coating film is more fixed, and the degree of orientation of the first light absorption anisotropic layer is further increased. A cooling means is not particularly limited, and a known method can be used.
Through the steps described above, the anisotropic light absorption layer of the present invention can be obtained.

(Other processes)
This production method may include a step of curing the first light absorption anisotropic layer (hereinafter also referred to as a “curing step”) after the alignment step.
The curing step is performed, for example, by heating and/or light irradiation (exposure). Among these, the curing step is preferably carried out by light irradiation.
Various light sources such as infrared light, visible light, and ultraviolet light can be used as the light source for curing, but ultraviolet light is preferred. Further, ultraviolet rays may be irradiated while being heated during curing, or ultraviolet rays may be irradiated through a filter that transmits only specific wavelengths.
Also, the exposure may be performed in a nitrogen atmosphere. When the anisotropic light absorption layer is cured by radical polymerization, it is preferable to perform the exposure in a nitrogen atmosphere because the inhibition of polymerization by oxygen is reduced.

<Other members>
The viewing angle control system may include members other than the polarizer and the first light absorption anisotropic layer described above.

(Second light absorption anisotropic layer)
The viewing angle control system may further include a second optical absorption anisotropic layer having an absorption axis parallel to the thickness direction. By including the second light absorption anisotropic layer, the viewing angle controllability is further improved.
In the second light absorption anisotropic layer, the absorption axis is parallel to the thickness direction. As described above, parallel does not mean parallel in a strict sense, but means a range of ±5° from parallel. Therefore, in the second light absorption anisotropic layer, the angle formed by the absorption axis and the thickness direction is in the range of 5° or less.

The second light absorption anisotropic layer preferably contains a dichroic substance like the first light absorption anisotropic layer. The types of dichroic substances are as described above.
Moreover, the second light absorption anisotropic layer preferably contains a liquid crystal compound, like the first light absorption anisotropic layer. The types of liquid crystal compounds are as described above.
A preferred embodiment of the second light absorption anisotropic layer is a layer in which a dichroic substance is vertically aligned in the thickness direction. The preferred mode as described above can be formed by adding a dichroic substance to the vertically aligned liquid crystal compound.

A method for forming the second light absorption anisotropic layer is not particularly limited, and known methods can be used. Among them, a method using a composition for forming the second light absorption anisotropic layer containing a dichroic substance and a liquid crystal compound is preferable.

The present invention also relates to a laminate including a first optically anisotropic layer and a second optically anisotropic layer.
By combining the laminate with the polarizer described above, a viewing angle control system can be constructed.

(Transparent substrate film)
The viewing angle control system may include a transparent substrate film.
The transparent substrate film may be used as a substrate for forming the first light absorption anisotropic layer, or may be used as a film for protecting the first light absorption anisotropic layer. The transparent substrate film may also serve as the retardation layer.
As the transparent substrate film, known transparent resin films, transparent resin plates, transparent resin sheets, and the like can be used, and there is no particular limitation.
Examples of transparent resin films include cellulose acylate films (e.g., cellulose triacetate film (refractive index: 1.48), cellulose diacetate film, cellulose acetate butyrate film, cellulose acetate propionate film), polyethylene terephthalate film, and polyethersulfone. Film, polyurethane resin film, polyester film, polycarbonate film, polysulfone film, polyether film, polymethylpentene film, polyetherketone film, (meth)acrylonitrile film, cycloolefin polymer film (using cycloolefin polymer polymer film), polycarbonate polymer film, polystyrene polymer film, or acrylic polymer film. The acrylic polymer film preferably contains an acrylic polymer containing at least one unit selected from lactone ring units, maleic anhydride units, and glutaric anhydride units.
The thickness of the transparent substrate film is preferably 20-100 μm.

(Alignment film)
The viewing angle control system may include an alignment film between the transparent substrate film and the first light absorption anisotropic layer.
The alignment film may be any layer as long as the dichroic substance can be in the desired alignment state on the alignment film, and is used in forming the above-described first light absorption anisotropic layer. oriented film.

(Other members)
The viewing angle control system may include an adhesive layer, an adhesive layer, a refractive index adjustment layer, a barrier layer, and the like, in addition to the members described above.

<Image display device>
The viewing angle control system of the present invention can be used for any image display device. That is, the present invention also relates to an image display device including the viewing angle control system.
The image display device is not particularly limited, and examples thereof include a liquid crystal display device, a self-luminous display device (organic EL (electroluminescence) display device, and a micro LED (light emitting diode) display device), and the like. Display panels in image display devices include display panels including liquid crystal cells, display panels of self-luminous display devices, and the like, and a viewing angle control system is arranged on these display panels.
A liquid crystal display usually has a liquid crystal cell and a backlight, and polarizers are provided on both the viewing side and the backlight side of the liquid crystal cell. The viewing angle control system of the present invention can be applied to either the viewing side or the backlight side of the liquid crystal display device, or can be applied to both sides. Application to a liquid crystal display device can be realized by replacing the polarizers on either or both surfaces of the liquid crystal display device with the viewing angle control system of the present invention. That is, the polarizers included in the viewing angle control system of the present invention can be used as the polarizers provided on both sides of the liquid crystal cell.
When the viewing angle control system of the present invention is applied to an organic EL display device, the viewing angle control system is arranged on the viewing side of the organic EL display device, and the polarizer in the viewing angle control system of the present invention is the first It is preferably arranged closer to the organic EL display device than the light absorption anisotropic layer. Further, it is preferable to place a λ/4 plate between the polarizer and the organic EL display device.
In addition, in the viewing angle control system in the image display device, it is preferable that the first light absorption anisotropic layer is arranged on the viewing side with respect to the polarizer.
The liquid crystal cell constituting the liquid crystal display device will be described in detail below.

(liquid crystal cell)
Liquid crystal cells used in liquid crystal display devices are preferably in VA (Vertical Alignment) mode, OCB (Optically Compensated Bend) mode, IPS (In-Plane-Switching) mode, or TN (Twisted Nematic) mode. , but not limited to these.
In the TN mode liquid crystal cell, the rod-like liquid crystalline molecules are substantially horizontally aligned when no voltage is applied, and are twisted at an angle of 60 to 120°. A TN mode liquid crystal cell is most widely used as a color TFT (Thin Film Transistor) liquid crystal display device, and is described in many documents.
In the VA mode liquid crystal cell, the rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied. VA mode liquid crystal cells include (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied and substantially horizontally aligned when voltage is applied (Japanese Unexamined Patent Application Publication No. 2-2002). 176625), and (2) a liquid crystal cell in which the VA mode is multi-domained (MVA mode) for widening the viewing angle (SID97, Digest of tech. Papers (preliminary collection) 28 (1997) 845). ), (3) A liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is performed when voltage is applied (Proceedings of the Japan Liquid Crystal Forum 58-59 (1998)) and (4) Survival mode liquid crystal cells (presented at LCD International 98). Moreover, any of PVA (Patterned Vertical Alignment) type, optical alignment type, and PSA (Polymer-Sustained Alignment) type may be used. Details of these modes are described in Japanese Unexamined Patent Application Publication No. 2006-215326 and Japanese National Publication of International Patent Application No. 2008-538819.
In the IPS mode liquid crystal cell, rod-like liquid crystal molecules are oriented substantially parallel to the substrate, and the liquid crystal molecules respond planarly by applying an electric field parallel to the substrate surface. In the IPS mode, a black display is obtained when no electric field is applied, and the absorption axes of the pair of upper and lower polarizers are perpendicular to each other. A method of using an optical compensatory sheet to reduce leakage light during black display in an oblique direction and improve the viewing angle is disclosed in Japanese Patent Application Laid-Open Nos. 10-54982, 11-202323 and 9-292522. JP-A-11-133408, JP-A-11-305217, and JP-A-10-307291.

The features of the present invention will be described more specifically below with examples and comparative examples. Materials, usage amounts, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as being restricted by the specific examples shown below.

<Preparation of transparent support 1 with alignment film>
The surface of a cellulose acylate film (TAC substrate having a thickness of 40 μm; TG40, Fuji Film Co., Ltd.) was saponified with an alkaline solution, and the following coating solution 1 for forming an alignment film was applied thereon with a wire bar. The cellulose acylate film on which the coating film was formed was dried with hot air at 60° C. for 60 seconds and further with hot air at 100° C. for 120 seconds to form an alignment film PA1, thereby obtaining a transparent support 1 with an alignment film.
The film thickness of the alignment film PA1 was 0.5 μm.

―――――――――――――――――――――――――――――――――
(Coating liquid 1 for forming alignment film)
―――――――――――――――――――――――――――――――――
・The following modified polyvinyl alcohol 3.80 parts by mass ・Initiator Irg2959 0.20 parts by mass ・Water 70 parts by mass ・Methanol 30 parts by mass ―――――――――――――――――――― ―――――――――――――

　Modified polyvinyl alcohol

<Formation of light absorption anisotropic layer P1>
On the obtained alignment film PA1, the following composition 1 for forming a light absorption anisotropic layer was continuously applied with a wire bar to form a coating film P1.
Next, the coating film P1 was heated at 140° C. for 30 seconds and then cooled to room temperature (23° C.).
Then, the coating film P1 was heated at 80° C. for 60 seconds and cooled to room temperature again.
After that, the coating film P1 is irradiated for 2 seconds under irradiation conditions of an illuminance of 200 mW/cm ² using an LED lamp (center wavelength 365 nm), thereby forming a light absorption anisotropic layer P1 on the alignment film PA1, and absorbing light. An anisotropic film P1 was obtained.
The film thickness of the light absorption anisotropic layer P1 was 3 μm, and the degree of orientation was 0.96.
The method for measuring the degree of orientation is as follows.
(Evaluation of degree of orientation)
In the light absorption anisotropic layer P1, a thin piece of the light absorption anisotropic layer P1 was cut using a microtome so as to be parallel to the direction of the absorption axis, and AxoScan OPMF-1 (manufactured by Optoscience) was used. , at a wavelength of 550 nm, the Mueller matrix of the flakes was measured. From the obtained Mueller matrix, the dichroic ratio D of the flake was calculated, and the degree of orientation S was calculated by the following formula.
S = (D-1)/(D+2)

―――――――――――――――――――――――――――――――――
(Composition 1 for forming light absorption anisotropic layer)
―――――――――――――――――――――――――――――――――
・The following dichroic substance D-1 7.976 parts by mass ・The following dichroic substance D-2 2.991 parts by mass ・The following dichroic substance D-3 12.562 parts by mass ・The following polymer liquid crystal compound P- 1 63.809 parts by mass, the following low molecular weight liquid crystal compound M-1 8.973 parts by mass, polymerization initiator IRGACUREOXE-02 (manufactured by BASF) 0.798 parts by mass, the following compound E-1 1.196 parts by mass, below Compound E-2 1.196 parts by mass Surfactant F-1 below 0.199 parts by mass Surfactant F-2 below 0.299 parts by mass Cyclopentanone 937.2 parts by mass Tetrahydrofuran 937.2 parts by mass part benzyl alcohol 19.9 parts by mass ――――――――――――――――――――――――――――――――

Dichroic substance D-1

Dichroic substance D-2

Dichroic substance D-3

　Polymer liquid crystal compound P-1

　Low molecular liquid crystal compound M-1

　Compound E-1

　Compound E-2

　Surfactant F-1

"Surfactant F-2"

<Formation of light absorption anisotropic layer P2>
The alignment film of the alignment film-attached transparent support 1 was subjected to a rubbing treatment, and the following composition P2 for forming a light absorption anisotropic layer was applied with a wire bar to form a coating film P2.
Next, the coating film P2 was heated at 120° C. for 30 seconds, and cooled to room temperature (23° C.).
Next, the coating film P2 was heated at 80° C. for 60 seconds and cooled to room temperature again.
Thereafter, the coating film P2 is irradiated for 1 second under irradiation conditions of an illuminance of 200 mW/cm ² using an LED lamp (central wavelength of 365 nm) to form a light absorption anisotropic layer P2 on the transparent support 1 with the alignment film. Then, a light-absorbing anisotropic film P2 was obtained.
The film thickness of the light absorption anisotropic layer P2 was 1.4 μm, and the surface energy was 26.5 mN/m.

―――――――――――――――――――――――――――――――――
Composition of Composition P2 for Forming Light-Absorbing Anisotropic Layer――――――――――――――――――――――――――――――――
· The dichroic substance D-1 7.356 parts by mass · The dichroic substance D-2 3.308 parts by mass · The dichroic substance D-3 11.02 parts by mass · The polymer liquid crystal compound P- 1 43.29 parts by mass 31.75 parts by mass of the low molecular liquid crystal compound M-1 Polymerization initiator IRGACUREOXE-02 (manufactured by BASF) 3.175 parts by mass 0.1027 parts by mass of the following surfactant F-3・Cyclopentanone 514.4 parts by mass ・Tetrahydrofuran 514.4 parts by mass ――――――――――――――――――――――――――――――――――

　Surfactant F-3

<Formation of light absorption anisotropic layer P3>
On the alignment film of the alignment film-attached transparent support 1, the following composition P3 for forming an anisotropic light absorption layer was continuously applied with a #4 wire bar to form a coating layer P3.
Next, the coating layer P3 was heated at 120° C. for 60 seconds and cooled to room temperature (23° C.).
Thereafter, a light absorption anisotropic layer P3 was produced on the transparent support 1 with the orientation film by irradiating for 60 seconds under irradiation conditions of an illuminance of 28 mW/cm ² using a high-pressure mercury lamp. got
The film thickness of the light absorption anisotropic layer P3 was 0.7 μm.

――――――――――――――――――――――――――――――――
Composition liquid P3 for forming light absorption anisotropic layer
――――――――――――――――――――――――――――――――
Dichroic azo dye compound D6 below 2.7 parts by mass Dichroic azo dye compound D7 below 2.7 parts by mass Dichroic azo dye compound D8 below 2.7 parts by mass Liquid crystalline compound M4 below 75. 5 parts by mass Polymerization initiator IRGACURE819 (manufactured by BASF) 0.8 parts by mass The following interface improver F-4 0.6 parts by mass Cyclopentanone 274.5 parts by mass Tetrahydrofuran 640.5 parts by mass --- ―――――――――――――――――――――――――――――

Dichroic azo dye compound D6

Dichroic azo dye compound D7

Dichroic azo dye compound D8

Liquid crystal compound M4 (compound A/compound B = 75/25 mixed)

(Compound A)

(Compound B)

　Interface improver F-4

<Measurement of Orientation Angle of Light Absorption Anisotropic Layer>
The prepared light absorption anisotropic film P1 was prepared by placing the light absorption anisotropic film P1 horizontally on a sample table using a polarimeter AxoScan OPMF-1 manufactured by Axomerics, and P-polarized light was incident on this film. The transmittance was measured while variously changing the azimuth angle and polar angle, and the azimuth angle and polar angle of the transmittance central axis of the light absorption anisotropic layer P1 in the light absorption anisotropic film P1 were investigated.
Similar measurements were also performed for the light-absorbing anisotropic films P2 and P3.
Furthermore, a section, which is an evaluation sample with a thickness of 2 μm, is taken from the light absorption anisotropic layer with a microtome parallel to a plane including the transmittance center axis and the film normal line. More specifically, the light absorption anisotropic layer obtained by peeling the orientation film-attached transparent support 1 from the light absorption anisotropic layer film (the light absorption anisotropic films P2 and P3) is coated with an embedding resin. From the sample 20 having the first embedding resin layer 22, the light absorption anisotropic layer 24, and the second embedding resin layer 26 in this order, as shown in FIG. A section 28, which is a 2 μm evaluation sample, is taken.
In the above, the evaluation sample of the light absorption anisotropic layer was obtained by peeling off the transparent support 1 with the alignment film, but it may be cut in a state in which various materials such as a support and a polarizer are adhered.
Next, as shown in FIG. 4, the section 28 is placed on the rotating table of the polarizing microscope, the linear polarizer of the polarizing microscope is set, and with the analyzer removed, the section 28 is rotated in the direction of the arrow. , the azimuth angle of the intercept (the angle at which the intercept is rotated) at which the cross section of the light absorption anisotropic layer exhibits the highest extinction with respect to the linearly polarized light incident from below the intercept (arrow in FIG. 4). At this time, it is assumed that the absorption axis of the intercept is perpendicular to the absorption axis of the polarizer of the polarizing microscope, and from this, the inclination of the absorption axis to the normal direction of the surface of the light absorption anisotropic layer is obtained.
In the light absorption anisotropic layer P1 in the light absorption anisotropic film P1, the absorption axis was oriented in the normal direction of the light absorption anisotropic layer P1 from the support side to the air side. That is, the dichroic substance was vertically aligned. The same was true for the anisotropic light absorption layer P3 in the anisotropic light absorption film P3.
In the anisotropic light absorption layer P2 in the anisotropic light absorption film P2, the angle θA between the absorption axis near the interface on the support side and the normal to the surface of the anisotropic light absorption layer was 80°. In other words, the angle formed by the long axis direction of the dichroic substance near the interface on the support side and the normal to the surface of the light absorption anisotropic layer was 80°. Further, the angle θB between the absorption axis near the air-side interface of the anisotropic light absorption layer P2 and the normal to the anisotropic light absorption layer was 50°. In other words, the angle formed by the long axis direction of the dichroic substance near the air-side interface and the normal to the surface of the light absorption anisotropic layer was 50°. The inclination angle of the absorption axis with respect to the normal direction of the surface of the anisotropic light absorption layer changed continuously from the vicinity of the interface on the support side toward the vicinity of the interface on the air side. In other words, there were countless regions including absorption axes inclined with respect to the normal direction of the surface of the light absorption anisotropic layer from the interface on the support side to the interface on the air side. The orthogonal projection of the absorption axis of each region onto the surface of the light absorption anisotropic layer was parallel.
That is, in the light absorption anisotropic layer P2, the liquid crystal compound was hybrid-oriented from the support side to the outside of the air, and the dichroic substance was also hybrid-oriented from the support side to the air side.

<Example 1>
An IPS mode liquid crystal display device, iPad Air (registered trademark) (manufactured by Apple Inc.), was disassembled and the liquid crystal cell was taken out. The prepared light-absorbing anisotropic film P1 was laminated on the viewing side polarizer of the liquid crystal cell so that the support was on the liquid crystal cell side. Furthermore, the prepared light-absorbing anisotropic film P2 is placed thereon so that the support is on the liquid crystal cell side, and the absorption axis of the polarizer on the viewing side and the prepared light-absorbing anisotropic film P2 It was laminated so that the direction of the lowest transmittance for linearly polarized light was parallel to the in-plane direction of the light absorption anisotropic layer P2.
In this manner, an image display device having a viewing angle control system including the viewer side polarizer and the light absorption anisotropic layer P2 was produced.
Note that the viewer-side polarizer in the iPad Air (registered trademark) (manufactured by Apple Inc.) had an absorption axis in the in-plane direction.

<Example 2>
An IPS mode liquid crystal display device, iPad Air (registered trademark) (manufactured by Apple Inc.), was disassembled and the liquid crystal cell was taken out. On the viewing side polarizer of the liquid crystal cell, the prepared light absorption anisotropic film P2 is placed so that the support is on the liquid crystal cell side, and the absorption axis of the viewing side polarizer and the light absorption anisotropy The film P2 was laminated so that the direction having the lowest transmittance for linearly polarized light (hereinafter also referred to as "specific direction D1") was parallel to the in-plane direction of the film P2.
Furthermore, the prepared light-absorbing anisotropic film P1 was laminated thereon so that the support was on the side of the liquid crystal cell.
Next, a second light-absorbing anisotropic film P2 is placed thereon so that the support is on the viewing side, and the absorption axis of the polarizer on the viewing side and the second light-absorbing anisotropic film They were laminated so that the direction with the lowest transmittance for linearly polarized light (hereinafter also referred to as “specific direction D2”) was parallel to the in-plane direction of P2. In order to explain the lamination state of the first light-absorbing anisotropic film P2 and the second light-absorbing anisotropic film P2, in FIG. The cross-sectional view which cut|disconnected the laminated body containing P2 and the light absorption anisotropic film P2 of the 2nd sheet in the specific direction D1 (or specific direction D2) is shown. In FIG. 5, the light absorption anisotropic film P1 is omitted. In FIG. 5, the support 30A and the light absorption anisotropy 32A in the first light absorption anisotropic film P1, and the support 30B and the light absorption in the second light absorption anisotropic film P1 Only the anisotropic layer 32B is shown, and also the dichroic material 34 present near the opposing interfaces of the light absorbing

anisotropic layers

32A and 32B. In FIG. 5, the dichroic substance present in regions other than near the interface between the light absorption

anisotropic layers

32A and 32B is omitted. As shown in FIG. 5, the light absorption anisotropic layer 32B side in the light absorption anisotropic layer 32A with respect to the stacking direction of the light absorption

anisotropic layers

32A and 32B (vertical direction of the paper surface in FIG. 5) The long axis direction of the dichroic material 32 near the surface of the is located in a place rotated counterclockwise, whereas the lamination direction of the light absorption

anisotropic layers

32A and 32B (vertical direction of the paper surface in FIG. 5) ), the long axis direction of the dichroic substance 32 near the surface of the anisotropic light absorption layer 32A in the anisotropic light absorption layer 32B is positioned at a position rotated clockwise, and The direction of rotation of the light absorption

anisotropic layers

32A and 32B of the dichroic material is opposite to the stacking direction. That is, the position of the dichroic substance 32 in the light absorption anisotropic layer 32A and the position of the dichroic substance 32 in the light absorption anisotropic layer 32B are line symmetrical in the cross-sectional view. there is
In this manner, an image display device having a viewing angle control system including the viewer side polarizer and the light absorption anisotropic layer P2 was produced.

<Example 3>
An image display device of Example 3 was produced in the same manner as in Example 1, except that the light-absorbing anisotropic film P1 was changed to the light-absorbing anisotropic film P3.

<Comparative Example 1>
An IPS mode liquid crystal display device, iPad Air (registered trademark) (manufactured by Apple Inc.), was disassembled and the liquid crystal cell was taken out. The prepared light-absorbing anisotropic film P1 was laminated on the viewing side polarizer of the liquid crystal cell so that the support was on the liquid crystal cell side. Thus, an image display device of Comparative Example 1 was produced.
The image display device of Comparative Example 1 does not include the viewing angle control system of the present invention.

<Performance evaluation>
(Evaluation of Reflection of Image on Window Glass)
As shown in FIG. 6, the image display device 40 of each example and comparative example manufactured by the above procedure is arranged such that the display surface 40A is perpendicular to the ground and the absorption axis of the polarizer on the viewing side of the image display device 40 It was fixed in a state in which the direction of was vertical to the ground. Further, as shown in FIG. 6, a glass plate 42 having a thickness of 2 mm was placed at an angle perpendicular to the screen of the display and the ground. Furthermore, the room was made into a dark room, a sample image was displayed on the display surface 40A, and reflection of the image on the glass plate 42 was visually evaluated sensorily.
AA: No reflection on the glass plate is visible A: Almost no reflection on the glass plate is visible B: Some reflection on the glass plate is visible C: Reflection on the glass plate is visible D: Reflection on the glass plate is strongly visible

(Front transmittance evaluation)
A sample image is displayed on the display surface of the image display device of each example and comparative example, and the luminance in the front direction is measured using a spectroradiometer SR-UL1R (manufactured by Topcon Technohouse), and evaluated according to the following criteria. did. When approximately the same brightness as that of the image display device of Comparative Example 1 is observed as in A, it can be said that the viewing angle control system has excellent transmittance in the front direction.
A: Compared with the luminance of the image display device of Comparative Example 1, substantially the same luminance was exhibited.
B: Compared with the brightness of the image display device of Comparative Example 1, the brightness was clearly inferior.

In Table 1, in the "presence/absence" column of the "first light absorption anisotropic layer" column, "yes" indicates that the viewing angle control system includes the first light absorption anisotropic layer, and "no" indicates that it does not. and
In Table 1, the column "number of layers" in the column "first light absorption anisotropic layer" indicates the number of layers of the first light absorption anisotropic layer included in the viewing angle control system.
In Table 1, in the "presence/absence" column of the "second light absorption anisotropic layer" column, "yes" indicates that the viewing angle control system includes the second light absorption anisotropic layer, and "no" indicates that it does not. and

As shown in Table 1, the viewing angle control system of the present invention exhibited the desired effect. In particular, in the example, reflection from the display surface onto the glass plate arranged in an oblique direction was suppressed. In other words, the display surface becomes more difficult to see at a specific azimuth angle where the reflection is suppressed, and the viewing angle controllability is higher.

REFERENCE SIGNS LIST 10 viewing angle control system 12 polarizer 14 first light absorption anisotropic layer 16 dichroic substance 20 sample 22 first embedding resin layer 24 light absorption anisotropic layer 26 second embedding resin layer 28

section

30A,

30B support Body

32A, 32B Light absorption anisotropic layer 34 Dichroic substance 40 Image display device 40A Display surface 42 Glass plate

Claims

Having a polarizer and a first light absorption anisotropic layer,
The polarizer has an absorption axis in the in-plane direction,
The angle formed by the azimuth with the lowest transmittance for linearly polarized light in the in-plane direction of the first light absorption anisotropic layer and the absorption axis of the polarizer is 0° or more and less than 45°,
The first light absorption anisotropic layer has a plurality of regions along the thickness direction, each having an absorption axis tilted with respect to the normal direction of the surface of the first light absorption anisotropic layer,
The viewing angle control system, wherein the plurality of regions have different angles of inclination of the absorption axis with respect to a normal direction of the surface of the first light absorption anisotropic layer.
2. The viewing angle according to claim 1, wherein the inclination angles of the absorption axes of the plurality of regions with respect to the normal direction of the surface of the first light absorption anisotropic layer continuously change along the thickness direction. control system.
The viewing angle control system according to claim 1 or 2, wherein the first light absorption anisotropic layer contains a liquid crystal compound and a dichroic substance.
The viewing angle control system according to any one of claims 1 to 3, further comprising a second light absorption anisotropic layer having an absorption axis parallel to the thickness direction.
An image display device including the viewing angle control system according to any one of claims 1 to 4.
The image display device according to claim 5, comprising a liquid crystal cell and said viewing angle control system arranged on said liquid crystal cell.
6. The image display device according to claim 5, comprising a self-luminous display device and the viewing angle control system arranged on the viewing side of the self-luminous display device.
A light absorption anisotropic layer,
along the thickness direction, having a plurality of regions having absorption axes inclined with respect to the normal direction of the surface of the light absorption anisotropic layer;
The anisotropic light absorption layer, wherein the angles of inclination of the absorption axes with respect to the normal direction of the surface of the anisotropic light absorption layer are different in the plurality of regions.
9. The optical absorption anisotropic layer according to claim 8, wherein the inclination angles of the absorption axes of the plurality of regions with respect to the normal direction of the surface of the optical absorption anisotropic layer continuously change along the thickness direction. tropic layer.
The anisotropic light absorption layer according to claim 8 or 9, wherein the anisotropic light absorption layer contains a liquid crystal compound and a dichroic substance.
A light absorption anisotropic layer according to any one of claims 8 to 10,
and a light absorption anisotropic layer having an absorption axis parallel to the thickness direction.