TW201935103A - Viewing angle expansion film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

A viewing angle expansion film for expanding the viewing angle, which is provided with one or more resin layers. This viewing angle expansion film is configured such that: one or more layers among the resin layers are pore-containing layers; each pore-containing layer is provided with a plurality of pore-containing parts that are generally parallel to each other; each pore-containing part contains a pore; the resin that constitutes the pore-containing layers contain an alicyclic structure-containing polymer and a hydrocarbon compound; and the hydrocarbon compound has a number average molecular weight of from 200 to 1,500.

Description

Viewing angle expanding film, polarizing plate and liquid crystal display device

The present invention relates to a viewing angle widening film, a polarizing plate, and a liquid crystal display device.

Liquid crystal display devices in the TN mode and the VA mode can be supplied relatively inexpensively on the one hand, but on the other hand, they often have poor display quality and narrow viewing angles when viewing the display surface from an oblique direction. Specifically, the relationship between the brightness of the image displayed on the screen and the measured brightness of the observation image is very different between the case of viewing from the front and the case of viewing from an oblique direction, which may make the liquid crystal display device Watching becomes difficult. For this reason, the TN mode liquid crystal display device has been mainly used in the past for display devices such as small and medium-sized televisions or personal computers. However, in recent years, devices such as tablet-type terminals that require viewing under a wide viewing angle have also attempted to use liquid crystal displays of these modes, together with means for expanding the viewing angle.

As an example of a means for expanding the viewing angle, a phase difference layer having a specific phase difference and thereby compensating the viewing angle is known. In addition, various methods have been proposed for manufacturing such a retardation layer (for example, Patent Documents 1 and 2).

『Patent Literature』
"Patent Document 1": Japanese Patent Publication No. 2013-151162 (corresponding publication: US Patent Application Publication No. 2002/180107)
"Patent Document 2": International Patent Publication No. 2009/084661 (corresponding bulletin: US Patent Application Publication No. 2011/039084)

However, a display device is desired in which a good display can be achieved in a wider range of viewing angles. Specifically, the following display devices are sought: maintaining the contrast of liquid crystal display devices at a high level, and in terms of gradation brightness characteristics (the relationship between the brightness of the image displayed on the screen and the brightness measured by observing this image), The gradation luminance characteristics observed from the oblique direction are similar to the gradation luminance characteristics observed from the front.

Furthermore, a viewing angle expansion film that can maintain good viewing angle expansion characteristics even after storage in a high-humidity environment and a high-temperature environment is desired.

Therefore, an object of the present invention is to provide a viewing angle widening film, a polarizing plate, and a liquid crystal display device that take into account both high contrast and a wide range of viewing angles and maintain good viewing angle expansion characteristics even after storage in a high humidity environment and a high temperature environment.

As a result of research conducted by the present inventor to solve the foregoing problems, it has been found that by using a film with a hole-containing layer as a viewing angle-enlarging film applied to a display device, such problems can be solved, and the present invention is completed. The hole-containing layer is composed of It is composed of an alicyclic structure polymer and a resin having a number average molecular weight of 200 to 1500.

That is, the present invention is as described below.

[1] A viewing angle expanding film, which is a viewing angle expanding film for expanding the viewing angle, wherein the viewing angle expanding film includes one or more resin layers,
One or more of the foregoing resin layers are pore-containing layers,
The hole-containing layer includes a plurality of hole-containing portions that are slightly parallel to each other.
The aforementioned hole-containing portion contains a hole,
The resin constituting the pore-containing layer includes an alicyclic structure-containing polymer and a hydrocarbon,
The number average molecular weight of the hydrocarbon is 200 to 1500.

[2] The viewing angle widening film according to claim 1, wherein the glass transition temperature (Tg) of the resin constituting the pore-containing layer is 115 ° C or higher.

[3] The viewing angle widening film according to [1] or [2], wherein the hydrocarbon is a hydrogenated petroleum resin.

[4] The viewing angle-expanding film according to any one of [1] to [3], in which the aforementioned hydrocarbon has a softening point of 90 ° C to 150 ° C and is selected from hydrogenated C9 petroleum resin and hydrogenated One or more cyclopentadiene-based petroleum resins.

[5] The viewing angle-enlarging film according to any one of [1] to [4], wherein the alicyclic structure-containing polymer is selected from the group consisting of a "norylene polymer, a monocyclic cyclic olefin polymer, and a ring Conjugated diene-based polymers, ethylene alicyclic hydrocarbon-based polymers, and these hydrides "polymers.

[6] The viewing angle widening film according to any one of [1] to [5], which includes two or more resin layers.

[7] The viewing angle widening film according to any one of [1] to [6], wherein an interval between the adjacent hole-containing portions is an indefinite interval of 50 μm or less.

[8] The viewing angle widening film according to any one of [1] to [7], which contains an ultraviolet absorber.

[9] The viewing angle widening film according to any one of [1] to [8], wherein the viewing angle widening film is a polarizing plate protective film.

[10] The viewing angle widening film according to any one of [1] to [9], wherein the hole-containing portion is formed by cracks.

[11] A polarizing plate including the viewing angle widening film and the polarizer as described in any one of [1] to [10].

[12] The polarizing plate according to [11], wherein a length direction of the hole-containing portion is parallel or perpendicular to an absorption axis of the polarizer.

[13] The polarizing plate according to [11], wherein the angle between the absorption axis of the polarizer and the longitudinal direction of the hole-containing portion is 45 °.

[14] A TN mode liquid crystal display device, which is a TN mode liquid crystal display device sequentially provided with a polarizing plate as described in [11] or [13] and a TN mode liquid crystal cell from the viewing side, wherein the aforementioned polarizing plate It is arranged such that the surface on the side of the viewing angle widening film becomes the viewing side,
When the display screen is viewed from an oblique direction, the azimuth angle in which the gradation is inverted is perpendicular to the angle between the longitudinal direction of the hole-containing portion.

[15] A VA mode liquid crystal display device, which is a VA mode liquid crystal display device sequentially provided with a polarizing plate as described in [11] or [12] and a VA mode liquid crystal cell from the viewing side, wherein the aforementioned polarizing plate It is arranged such that the surface on the side of the viewing angle widening film becomes the viewing side,
The longitudinal direction of the hole-containing portion is parallel to the absorption axis of the polarizer.

According to the present invention, it is possible to provide a viewing angle widening film, a polarizing plate, and a liquid crystal display device that take into account both high contrast and a wide range of viewing angles and maintain good viewing angle expansion characteristics even after storage in a high humidity environment and a high temperature environment.

The embodiments and examples are disclosed below to explain the present invention in detail. However, the present invention is not limited to the implementation modes and examples disclosed below, and can be implemented with arbitrary changes without departing from the scope of the patent application of the present invention and its equivalent scope.

In the following description, the "polarizing plate" includes not only a rigid member but also a member having flexibility such as a resin film.

In the following description, the direction of the constituent elements is "45 °", "parallel", "vertical" or "orthogonal", and unless otherwise noted, within the range that does not impair the effect of the present invention, it may also include : Error is usually within ± 5 °, preferably within ± 2 °, and within a better range of ± 1 °.

Furthermore, in the following description, the MD direction (machine direction) is the flow direction of the film in the production line, and the TD direction (traverse direction) is a direction parallel to the film surface and perpendicular to the MD direction. In addition, the length direction of the long film is called the MD direction of the film, and the width direction is called the TD direction of the film. In the following description, the "long" film refers to a film having a length of 5 times or more with respect to the width, and preferably a length of 10 times or more, and specifically, a roll having a rewindable roll. The length of the film is stored or transported. The upper limit of the length of the long film is not particularly limited, but may be set to, for example, 100,000 times or less the width.

In the following description, the in-plane retardation Re of a film such as a viewing angle widening film is a value represented by Re = (nx-ny) × d unless otherwise noted. The retardation Rth in the thickness direction of the film is a value represented by Rth = [(nx + ny) / 2-nz] × d unless otherwise noted. Here, nx represents the refractive index that is the in-plane direction of the film--that is, the direction perpendicular to the thickness direction--and the direction that gives the maximum refractive index. ny represents a refractive index which is a direction in the plane and a direction orthogonal to the direction of nx. nz represents the refractive index in the thickness direction. d represents the thickness of the film. Measurement wavelength, unless otherwise noted, is 590 nm.

[1. Overview of viewing angle widening film]

The viewing angle widening film of the present invention is a film for expanding the viewing angle of a liquid crystal display device.

The viewing angle widening film includes one or more resin layers. One or more of the resin layers are pore-containing layers.

[2. Materials with pore layer]

The resin constituting the pore-containing layer includes an alicyclic structure-containing polymer and a hydrocarbon.

[2.1. Polymers with alicyclic structure]

In the present invention, since the resin constituting the pore-containing layer contains an alicyclic structure polymer which is a polymer having a low water absorption rate, it is possible to maintain good viewing angle expansion characteristics even after storage in a high-humidity environment.

Examples of the alicyclic structure-containing polymer include (1) a norbornene-based polymer, (2) a monocyclic cyclic olefin-based polymer, (3) a cyclic conjugated diene-based polymer, and (4) Ethylene alicyclic hydrocarbon polymers and hydrides such as (1) to (4). Among these, from the viewpoints of heat resistance, mechanical strength, and the like, a norbornene-based polymer and a hydride thereof are preferable.

Examples of the norbornene-based polymer include a ring-opening polymer of a norylene monomer, a ring-opening copolymer of a norylene monomer and other monomers capable of ring-opening copolymerization, and hydrides thereof; Addition polymers, addition copolymers of norbornene monomers and other monomers capable of copolymerization. Among these, from the viewpoint of transparency, the "hydrogenated product of a ring-opening polymer of a norylene monomer" or "the ring-opening copolymer of a norylene monomer and another monomer capable of ring-opening copolymerization" "Hydride" is particularly preferred.

The polystyrene-equivalent or polyisoprene-equivalent weight average molecular weight of the alicyclic structure-containing polymer measured by gel permeation chromatography is usually 5,000 or more, preferably 10,000 or more, and 15,000 or more It is preferably, and usually 50,000 or less, preferably 45,000 or less, and more preferably 40,000 or less. The number average molecular weight usually exceeds 1,500, preferably 5,000 or more, preferably 10,000 or more, and usually 40,000 or less, preferably 35,000 or less, and more preferably 30,000 or less.

[2.1.1. Hydrogenated block copolymer [G]]

Examples of the polymer having an alicyclic structure include a hydrogenated block copolymer [G] including two or more polymer blocks [D] and one or more polymer blocks [E]. The polymer block [D] has a cyclic hydrocarbon group-containing compound hydride unit [I]; the polymer block [D] has a chain hydrocarbon hydride unit [II], or a combination of the unit [I] and the unit [II] .

[Cycloalkyl-containing compound hydride unit [I]]

The cyclic hydrocarbon group-containing compound hydride unit [I] is a structural unit having a structure obtained by "polymerizing a cyclic hydrocarbon group-containing compound, and further hydrogenating its unsaturated bond if the unit obtained by such polymerization has an unsaturated bond". However, the cyclic hydrocarbon-containing compound hydride unit [I] also includes a unit obtained by any manufacturing method as long as it has the structure.

The cyclic hydrocarbon group-containing compound hydride unit [I] is preferably a structural unit obtained by polymerization of an aromatic vinyl compound. More specifically, it is a structural unit (aromatic vinyl compound hydride unit [I]) having a structure obtained by polymerizing an aromatic vinyl compound and hydrogenating its unsaturated bond. However, the aromatic vinyl compound hydride unit [I] also includes a unit obtained by any manufacturing method as long as it has the structure.

Similarly, in this application, for example, a structural unit having a structure obtained by "polymerizing styrene and hydrogenating its unsaturated bond" is sometimes referred to as a styrene hydride unit. The styrene hydride unit also includes a unit obtained by any manufacturing method as long as it has the structure.

Examples of the aromatic vinyl compound hydride unit [I] include a structural unit represented by the following structural formula (1).

『Hua1』

In the structural formula (1), R ^c represents an alicyclic hydrocarbon group. Examples of R ^c include cyclohexyls such as cyclohexyl, and decalinyls.

In the structural formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, a fluorenylamino group, a fluorenimine group, and a silicon atom. Or a chain hydrocarbon group substituted with a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amido group, amidino group or silyl group). Among them, R ¹ , R ² and R ³ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms in terms of heat resistance, low birefringence, and mechanical strength. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

A good specific example of the aromatic vinyl compound hydride unit [I] includes a structural unit represented by the following formula (1-1). The structural unit represented by the formula (1-1) is a styrene hydride unit.

『Hua 2』

Those having stereoisomers in the examples of the cyclic hydrocarbon group-containing hydride unit [I] may use any of the stereoisomers. The cyclic hydrocarbon group-containing compound hydride unit [I] may be used singly or in combination of two or more kinds in any ratio.

[Chain hydride unit [II]]

The paraffin hydride unit [II] is a structural unit having a structure obtained by "polymerizing a paraffin, and if a unit obtained by such polymerization has an unsaturated bond, further hydrogenating the unsaturated bond". However, the chain hydrocarbon hydride unit [II] also includes a unit obtained by any manufacturing method as long as it has the structure.

The hydrocarbon hydride unit [II] is preferably a structural unit obtained by polymerization of a diene compound. More specifically, it is a structural unit having a structure obtained by "polymerizing a diene compound and further hydrogenating an unsaturated bond if a unit obtained through such polymerization has an unsaturated bond" (diene compound hydride unit [ II]). However, the diene compound hydride unit [II] also includes a unit obtained by any manufacturing method as long as it has the structure.

Similarly, in this application, for example, a structural unit having a structure obtained by "polymerizing isoprene and then hydrogenating its unsaturated bond" is sometimes referred to as an isoprene hydride unit. The isoprene hydride unit also includes a unit obtained by any manufacturing method as long as it has the structure.

The diene compound hydride unit [II] is preferably a structural unit obtained by polymerization of a conjugated diene compound. More specifically, it is preferable to have a structure obtained by polymerizing a conjugated diene compound such as a chain conjugated diene compound and then hydrogenating its unsaturated bond. Examples thereof include the following structural units represented by the structural formula (2) and structural units represented by the structural formula (3).

『Hua 3』

In the structural formula (2), R ⁴ to R ⁹ each independently represent a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, a fluorenylamino group, a fluorenimine group, a silicon group, or a hydrogen atom. A hydrocarbon group substituted with a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amido group, amidino group or silyl group). Among them, R ⁴ to R ⁹ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms from the viewpoints of heat resistance, low birefringence, and mechanical strength. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

『Hua 4』

In the structural formula (3), R ¹⁰ to R ¹⁵ each independently represent a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, a fluorenylamino group, a fluorenimine group, a silicon group, or a hydrogen atom. A hydrocarbon group substituted with a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amido group, amidino group or silyl group). Among them, R ¹⁰ to R ¹⁵ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms from the viewpoints of heat resistance, low birefringence, and mechanical strength. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

As a good specific example of a diene compound hydride unit [II], the structural unit represented by following formula (2-1)-(2-3) is mentioned. The structural unit represented by the formulae (2-1) to (2-3) is an isoprene hydride unit.

『Hua 5』

Those having stereoisomers in the examples of the chain hydride unit [II] may use any of the stereoisomers. The hydrocarbon hydride unit [II] may be used singly or in combination of two or more kinds in any ratio.

[2.1.2. Details of hydrogenated block copolymer [G]]

The hydrogenated block copolymer [G] preferably has a triblock molecular structure having "one block [E] per molecule and two blocks [D] connected to each end thereof" at each end thereof ". . That is, the hydrogenated block copolymer [G] contains "1 block per molecule [E]; 1 molecule per molecule is connected to one end of the block [E] and has a cyclic hydrocarbon group-containing compound hydride unit [I] ] Block [D1]; a triblock copolymer with a block [D2] "which is connected to the other end of the block [E] and has a cyclic hydrocarbon-containing compound hydride unit [I] per molecule is good.

In the above-mentioned hydrogenated block copolymer [G] as a triblock copolymer, from the viewpoint of easily obtaining a pore-containing layer having good characteristics, the sum of the block [D1] and the block [D2] and the embedding It is preferable that the weight ratio (D1 + D2) / E of the segment [E] falls within a specific range. Specifically, the weight ratio (D1 + D2) / E is preferably 45/55 or more, 50/50 or more is preferable, 89/11 or less is preferable, and 86/14 or less is preferable.

In addition, in the above-mentioned hydrogenated block copolymer [G], which is a triblock copolymer, from the viewpoint of easily obtaining a pore-containing layer having good characteristics, the weight of the block [D1] and the block [D2] It is better that the ratio D1 / D2 falls within a specific range. Specifically, when D1 ≧ D2, the weight ratio D1 / D2 is preferably 1 or more, 3 or more is preferred, 5 or more is particularly preferred, and 15 or less is preferred, 14 or less is preferred, and 13 or less is particularly preferred.

The weight average molecular weight Mw of the hydrogenated block copolymer [G] is preferably 35,000 or more, more preferably 50,000 or more, more preferably 55,000 or more, particularly preferably 60,000 or more, and more preferably 85,000 or less, and 80,000. The following is preferred, and below 75,000 is particularly preferred. When the weight average molecular weight Mw is in the aforementioned range, a pore-containing layer having good characteristics can be easily obtained.

The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the hydrogenated block copolymer [G] is preferably 2.0 or less, more preferably 1.7 or less, particularly preferably 1.5 or less, and 1.0 The above is better. When the weight average molecular weight Mw is in the aforementioned range, the viscosity of the polymer can be reduced to improve the moldability.

The weight average molecular weight Mw and the number average molecular weight Mn of the hydrogenated block copolymer [G] were measured by gel permeation chromatography using tetrahydrofuran as a solvent, and the values were measured in terms of polystyrene.

The block [D1] and the block [D2] are preferably each independently composed only of the cyclic hydrocarbon group-containing compound hydride unit [I], but may include any unit other than the cyclic hydrocarbon group-containing compound hydride unit [I]. Examples of the arbitrary structural unit include structural units based on an ethylene compound other than the cyclic hydrocarbon group-containing compound hydride unit [I]. The content rate of any structural unit in the block [D] is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 1% by weight or less.

The block [E] is preferably "made from only the hydrocarbon hydride unit [II]" or "made only from the cyclic hydrocarbon group-containing compound hydride unit [I] and the hydrocarbon hydride unit [II]", but Any unit other than units [I] and [II] must be included. Examples of the arbitrary structural unit include structural units based on an ethylene compound other than the units [I] and [II]. The content of any structural unit in the block [E] is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 1% by weight or less.

When the block [E] contains a cyclic hydrocarbon group-containing compound hydride unit [I] and a chain hydrocarbon hydride unit [II], the weight ratio [I] and [II] of the units [I] in the block [E] ] / [II], preferably 0.01 or more, more preferably 0.1 or more, more preferably 0.2 or more, more preferably 0.3 or more, and preferably 1.5 or less, preferably 1.4 or less, and 1.3 or less Especially good.

In addition, the weight ratio [I] / [II] of the units [I] and [II] in the molecule of the hydrogenated block copolymer [G] is preferably 70/30 or more, and more preferably 72/28 or more It is more preferably 74/26 or more, and 89/11 or less, 85/15 or less, and 83/17 or less. With the ratio of the units [I] and [II] in the aforementioned range, a pore-containing layer having good characteristics can be easily obtained.

The production method of the hydrogenated block copolymer [G] is not particularly limited, and an arbitrary production method may be adopted. The hydrogenated block copolymer [G] can be obtained, for example, by preparing monomers corresponding to a cyclic hydrocarbon group-containing compound hydride unit [I] and a chain hydrocarbon hydride unit [II], and then polymerizing and then hydrogenating them. Polymer [F]. For specific manufacturing, the method described in International Patent Publication No. WO2016 / 152871 and other known methods may be appropriately combined for implementation. The hydrogenation rate in the hydrogenation reaction is usually 90% or more, preferably 95% or more, and more preferably 97% or more. By increasing the hydrogenation rate, the low birefringence and thermal stability of the hydrogenated block copolymer [G] can be improved. The hydrogenation rate can be measured by ¹ H-NMR.

[2.2. Hydrocarbons]

The resin constituting the pore-containing layer contains a hydrocarbon. In the present invention, the resin constituting the pore-containing layer contains hydrocarbons having a number-average molecular weight of 200 to 1500, so that pores having an enlarged viewing angle characteristic can be made visible.

The number average molecular weight of the hydrocarbon is 200 to 1500. The number average molecular weight of the hydrocarbon is preferably 300 or more, more preferably 500 or more, and preferably 1400 or less, and more preferably 1300 or less. The effect that the hydrocarbon does not bleed out can be obtained by setting the number average molecular weight of the hydrocarbon to be higher than the lower limit value, and by making the number average molecular weight to be the upper limit value or less, it is possible to make holes with better viewing angle expanding characteristics appear.

Examples of the hydrocarbon include petroleum resins and plant-based hydrocarbon resins. Generally speaking, a hydrocarbon is a compound composed of only carbon atoms and hydrogen atoms. However, in the present application, it is understood in a broader sense. The term "hydrocarbon" also includes compounds containing a small proportion of oxygen atoms. Specifically, the vocabulary also includes compounds having 1 oxygen atom or a smaller proportion of oxygen atoms relative to 8 carbon atoms.

The so-called petroleum resin refers to those obtained by polymerizing diolefins and monoolefins in the distillate distillate fractions associated with the production of ethylene by steam cracking as a main component and polymerizing them by a well-known method.

Examples of petroleum resins include: C5 petroleum resins (the aforementioned fractions are C5 fractions such as isoprene, 1,3-pentadiene, cyclopentene, cyclopentadiene, and dicyclopentadiene (DCPD). Raw materials), C9-based petroleum resins (the aforementioned distillates are based on C9 fractions such as vinyl toluene, α-methylstyrene, indene, and alkylindene), C5-based and C9-based copolymerized petroleum resins, and hydrogenated C5-based Petroleum resins, hydrogenated C9 petroleum resins, and petroleum resins and their hydrides (hydrogenated DCPD petroleum resins) that are copolymers of DCPD and other compounds (eg, copolymers of DCPD and C9 fractions, DCPD and aromatic compounds Copolymers and these hydrides).

Specific examples include: Arakon Chemical Industry (Stock) trade name "ARKON (registered trademark)", Tosoh (Stock) trade name "Petcoal (registered trademark)", Idemitsu Petrochemical (Stock) Trade names are "I-MARV", T-REZ H series made by JXTG Energy Co., Ltd., etc.

Examples of the plant-based hydrocarbon resin include rosin acid, dimer acid (bifunctional C36 compound, etc.), various terpene resins (pinene resin, diterpene resin, aromatic modified terpene resin, terpene phenol resin, and hydrogenated terpene resin). ).

Specific examples include a turpentine derivative made by Arakawa Chemical Industries, Ltd., a hydrodimeric acid made by Croda Japan, and a terpene resin made by Yasuhara Chemical.

In the present invention, one kind or two or more kinds of hydrocarbons can be used. The hydrocarbon is preferably a hydrogenated petroleum resin, and more preferably one or more selected from the group consisting of hydrogenated C9-based petroleum resin and hydrogenated DCPD-based petroleum resin.

The hydrocarbon preferably has a softening point of 90 ° C or higher and 150 ° C or lower. The softening point of the hydrocarbon is preferably 100 ° C or higher, more preferably 110 ° C or higher, more preferably 143 ° C or lower, and even more preferably 145 ° C or lower. By setting the softening point of the hydrocarbons below the upper limit value, it is possible to make holes with better viewing angle expansion characteristics appear in the viewing angle expansion film, and by setting the softening point above the lower limit value, even after storage in a high temperature environment Still have to maintain good viewing angle expansion characteristics. The aforementioned softening point can be measured by the ring and ball method prescribed by JIS K 2531.

[2.2.1. Proportion of hydrocarbons]

The proportion of the hydrocarbon in the resin constituting the pore-containing layer is preferably 0.5% by weight or more, more preferably 5% by weight or more, and 40% by weight or less with respect to the total amount of the alicyclic structure-containing polymer and the hydrocarbon. Preferably, it is less than 35% by weight. By setting the hydrocarbons above the lower limit value, holes with good viewing angle expansion characteristics can be made visible, and by setting the hydrocarbons below the upper limit value, it is possible to maintain good viewing angle expansion characteristics even after storage in a high humidity environment. .

[2.3. Characteristics of resin constituting pore-containing layer]

The glass transition temperature (Tg) of the resin constituting the pore-containing layer is preferably 115 ° C or higher, more preferably 118 ° C or higher, and even more preferably 120 ° C or higher. The upper limit of the glass transition temperature is not particularly limited, but is preferably 160 ° C or lower, and more preferably 150 ° C or lower. By setting the Tg of the resin constituting the pore-containing layer to a lower limit value or more, it is possible to maintain good viewing angle widening characteristics even after storage in a high-temperature environment.

The resin constituting the pore-containing layer may optionally contain any component other than the alicyclic structure-containing polymer and the hydrocarbon. Examples of the optional components include ultraviolet absorbers, antioxidants, heat stabilizers, light stabilizers, antistatic agents, dispersants, chlorine capture agents, flame retardants, nucleating agents, reinforcing agents, anti-caking agents, and anti-blocking agents. Aerosols, release agents, pigments, organic or inorganic fillers, neutralizers, lubricants, decomposers, metal deactivators, antifouling agents and antibacterial agents.

The resin constituting the pore-containing layer preferably contains an ultraviolet absorber.

Examples of the ultraviolet absorber include oxydiphenylketone-based compounds, benzotriazole-based compounds, salicylate-based compounds, diphenylketone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and acrylonitrile. UV absorber, tertiary compound, nickel salt compound and inorganic powder. Examples of suitable ultraviolet absorbers include: 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl ) Phenol], 2- (2'-hydroxy-3'-tertiary butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2,4-bis (tertiary butyl) -6 -(5-chlorobenzotriazol-2-yl) phenol, 2,2'-dihydroxy-4,4'-dimethoxydiphenyl ketone, 2,2 ', 4,4'-tetrahydroxyl Diphenyl ketone. Examples of particularly suitable ones include: 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol].

When the resin constituting the pore-containing layer contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 0.5 to 5% by weight per 100% by weight of the resin.

[3. Characteristics of Porous Layer]

In the case where the hole-containing layer has optical anisotropy, its refractive index is determined as (nx + ny) / 2.

The viewing angle widening film of the present invention may have only one hole-containing layer or two or more layers. In the case where the viewing angle widening film of the present invention has two or more pore-containing layers, the materials exemplified above may be used as a material constituting each resin layer.

The thickness of the pore-containing layer is preferably 0.2 μm or more, more preferably 0.5 μm or more, more preferably 20 μm or less, and even more preferably 10 μm or less. When the viewing angle widening film includes two or more pore-containing layers, the total thickness of the pore-containing layer is preferably within this range. When the thickness of the pore-containing layer is within such a range, the pore-containing layer having the effect of the present invention can be easily constructed.

[4. Resin layer other than pore-containing layer]

The viewing angle widening film of the present invention may include only a pore-containing layer as a resin layer, or a combination of any resin layer including a pore-containing layer and a non-pore-containing layer. By combining the pore-containing layer with a resin layer other than this, an effective viewing angle widening film can be formed.

An example of such an arbitrary resin layer is a reinforcing layer having a higher strength than the pore-containing layer. The hole-containing layer may be low in strength due to the presence of holes. By providing such a reinforcing layer, a viewing angle-enlarging film having both optical performance and strength can be obtained.

As another example of the arbitrary resin layer, a protective layer provided on one or both of the front face and the back face of the hole-containing layer may be mentioned. The hole-containing layer may have irregularities on its surface due to the inclusion of holes. By providing such a protective layer, a viewing angle widening film having both optical performance and surface smoothness can be obtained. The protective layer may also have a function as a reinforcing layer as described above. For example, if the viewing angle widening film of the present invention is made into a layered structure with two types of skin layers / core layers / skin layers, the core layer is made into a porous layer, and the skin layer is made to play. A layer body functioning as a reinforcing layer and / or a protective layer.

As another example of the arbitrary resin layer, an easy-to-bond layer for improving the bonding property between the viewing angle widening film and other members is mentioned.

When the viewing angle widening film of the present invention has a resin layer other than the pore-containing layer, the resin constituting such a layered body is not particularly limited, but any material having desired characteristics may be appropriately selected. For example, examples of the resin constituting the reinforcing layer and the protective layer include those selected from the group consisting of polystyrene, polypropylene, polyethylene, polyester, polyamide, polyvinylidene fluoride, and an alicyclic structure-containing polymer. A polymer is used as a polymer resin. As the resin constituting the reinforcing layer and the protective layer, those having desirable characteristics among examples of these resins must be appropriately selected.

The thickness of the viewing angle widening film is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. The upper limit is not particularly limited, but is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less.

[5. With holes]

The pore-containing layer in the viewing angle widening film of the present invention includes a plurality of pore-containing portions which are slightly parallel to each other, and the pore-containing portions include holes.

FIG. 1 is a schematic plan view showing an example of a viewing angle widening film. In the example of FIG. 1, the elongated viewing angle widening film 1 is composed of only one hole-containing layer, and includes a plurality of linear hole-containing portions 20 parallel to each other. Each hole-containing portion 20 is illustrated as a thin line in FIG. 1, but the hole-containing portion 20 is a region having a width and a depth, and a plurality of holes are provided therein (not shown in FIG. 1). In the example of FIG. 1, the longitudinal direction of the hole-containing portion 20 is a direction parallel to the TD direction of the viewing angle widening film 1.

Since the hole-containing portion contains holes, light incident on the hole-containing portion is scattered. In addition, since the pore-containing portion has a pore, the refractive index of the pore-containing portion is different from that of the pore-containing layer where the pore-containing portion is not formed. As a result, the angle of the scattering direction of the light is enlarged. Although unwilling to be bound by a particular theory, it is conceivable that by this type of scattering of light in a wide range, an expansion of the viewing angle can be achieved.

The hole included in the hole-containing portion may or may not penetrate through the thickness direction of the viewing angle expanding film. In any case, since the hole-containing portion contains holes, it has a structure having a depth in the thickness direction of the viewing angle widening film. Each hole-containing portion usually has a plurality of holes, but the structure of the hole-containing portion is not limited to this, and may be a single crack-shaped hole. The depth of the pore-containing portion may span the entire thickness direction of the pore-containing layer, or it may span only a portion.

The plurality of hole-containing portions are arranged slightly parallel to each other. The so-called "hole-containing portions" are "slightly parallel" to each other, and within the range in which the effects of the present invention can be obtained, the angles between the two can be more than 0 °. Specifically, the error may be within ± 40 °, and within ± 30 °. Since the pore-containing portions that are "slightly parallel" to each other have such an angular relationship, in the pore-containing layer, a plurality of pore-containing portions may also have intersections with each other.

Each hole-containing portion generally has a slightly linear shape. The shape of the hole-containing portion is “slightly straight”, and includes a case where there is a wrinkle within a range where the effect of the present invention can be obtained.

Moreover, from the viewpoint of the ease of forming the hole-containing portion, it is preferable that the length direction of the hole-containing portion is slightly parallel to the TD direction of the viewing angle widening film (slightly perpendicular to the MD direction). In this case, as shown in FIG. 1, there is no need to form a straight line from one edge portion of the viewing angle widening film 1 to the other edge portion facing the edge portion.

The interval P between adjacent hole-containing portions may be constant or indefinite. For example, in the example shown in FIG. 1, the interval P between adjacent hole-containing portions 20 is not constant, but is an indefinite interval. From the viewpoint of obtaining the effect of a highly enlarged viewing angle, the interval containing the holes is preferably indefinite.

The interval P between adjacent hole-containing portions is not particularly limited, but from the viewpoint of suppressing phenomena such as moire interference and obtaining good display screen quality, it is preferable to use a narrow interval. Specifically, such an interval P is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 5 μm or less. When the interval P is indefinite, it is preferable that the maximum value of the interval P in the viewing angle widening film is equal to or less than the upper limit. In addition, the lower limit of the interval P is not particularly limited, but is set to be 0.5 μm or more.

In a good aspect, the plurality of pore-containing portions included in the viewing angle widening film are partially or entirely formed by cracks. From the viewpoint of easiness of formation of the pore-containing portion, the pore-containing portion is preferably formed by cracks.

The so-called crack refers to a slightly linear crack formed in a thin film. Cracks usually have fibrils formed between such cracks, and voids formed between them as holes. The fibril means a fiber obtained by fibrillation of molecules constituting a resin.

FIG. 2 is an enlarged schematic diagram showing an example of a crack structure. In FIG. 2, the crack 21 has a plurality of elongated fibrils 211 and a gap 212 existing therebetween. The fibrils 211 generally extend and extend in a direction slightly orthogonal to the length direction of the crack containing the pores. A crack having such a structure can be formed by cracking a thin film. The film is subjected to crack processing, and then pressure is applied to the film, so that the film can form cracks. Furthermore, the molecules constituting the resin can be fibrillated in the gaps between the cracks to form fibrils and the spaces between them. Details of the crack processing will be described later.

The diameter of the fibril is usually 5 nm to 50 nm, preferably 10 nm to 50 nm, more preferably 10 nm to 40 nm, and even more preferably 20 nm to 40 nm. The diameter of the void in the crack is usually 5 nm to 45 nm, and preferably 10 nm to 30 nm. In the case where the pore-containing portion is formed by cracks, the width of such cracks is usually 20 nm to 800 nm, preferably 30 nm to 600 nm, and more preferably 40 nm to 300 nm. The crack height is usually 0.3 μm to 50 μm, preferably 0.4 μm to 30 μm, and more preferably 0.5 μm to 20 μm. Here, the values of the diameter of fibrils, the diameter of voids, the width of cracks, and the height of cracks are average values. Specifically, any three places where cracks appear can be observed with a scanning electron microscope, and then the fibrils and voids are measured. To find the size.

[6. Shape and physical properties of viewing angle widening film]

The viewing angle widening film of the present invention may be a long film, or may be a slitted film. Generally, from the viewpoint of improving manufacturing efficiency, a viewing angle widening film is a thin film that is manufactured into a long strip. In addition, in the case of manufacturing a cut-angle viewing angle expansion film, it is necessary to manufacture a cut-angle viewing angle expansion film by cutting a long viewing angle expansion film into a desired shape.

The viewing angle widening film of the present invention may be a film with small optical anisotropy, substantially optically isotropic, or an optically anisotropic film. In the case where the viewing angle-enlarging film is optically anisotropic, such anisotropy may be caused by a layer containing pores, or may be caused by a layer body other than a layer containing pores, or may be caused by both parties. By.

In the case where the viewing angle widening film of the present invention is an optically anisotropic film, its in-plane retardation Re is preferably 360 nm or less, more preferably 330 nm or less, and even more preferably 300 nm or less. The lower limit is not particularly limited, but is preferably 10 nm or more, more preferably 20 nm or more, and more preferably 30 nm or more. The retardation Rth in the thickness direction is preferably 400 nm or less, more preferably 350 nm or less, and even more preferably 300 nm or less. The lower limit is not particularly limited, but is preferably 10 nm or more, more preferably 20 nm or more, and more preferably 30 nm or more.

The full light transmittance of the viewing angle widening film is preferably 70% or more, and more preferably 80% or more. The light transmittance was measured in accordance with JIS K0115, using a spectrophotometer (manufactured by JASCO Corporation, UV-visible near-infrared spectrophotometer "V-570").

[7. Manufacturing method of viewing angle widening film]

The viewing angle widening film of the present invention can be produced by any method such as a known method. For example, after the film for forming the hole-containing portion is manufactured, the hole-containing portion may be formed in one or more layers of the film, thereby manufacturing the viewing angle widening film of the present invention. In this application, such a film for forming a hole-containing portion is sometimes referred to as a "material film".

[7.1. Manufacture of material film]

The layer structure of the material film is not particularly limited, and a layer structure suitable for the layer structure of the desired viewing angle-enlarging film must be made. For example, a layered structure including "a layered body that becomes a porous layer" and "a layered body that becomes a resin layer other than that" can be made. More specifically, it is necessary to combine "a layer body that can be processed into a pore-containing layer through cracks" and "a layer body that does not generate cracks even through such crack processing" to constitute "to have a pore-containing layer "Resin layer" is a material film with a viewing angle widening film.

Examples of the method for manufacturing the material film include an injection molding method, an extrusion molding method, a pressure molding method, an inflation molding method, a blow molding method, a calender molding method, a die casting method, and a compression molding method.

Conditions such as the temperature of the molten resin during the production of the material film can be appropriately changed according to the type of the material film, and can be performed under well-known conditions.

When the material film includes two or more resin layers, examples of a method for producing the material film include a co-extrusion T-die method, a co-extrusion inflation method, a co-extrusion lamination method, and a dry lamination method. Co-casting method and coating forming method.

When the material film includes two or more resin layers, the material film is preferably produced by a coating molding method. In the case of the coating molding method, for example, a resin that is a material of a layer (layer A) can be formed into a thin film, and then the film of the layer A can be coated as The resin of the material of the layered body other than the layered body A is dissolved in a coating solution made of a solvent and dried to obtain a material film.

The material film may be an unstretched unstretched film or a stretched stretched film. Generally speaking, the stretched film has a small tensile elongation and it is easy to form cracks. Therefore, for example, a stretched film formed of a certain material and an unstretched film formed of the same material are bonded to form a multilayer material film, and crack processing is performed on the stretched film, so that only the stretched film can be displayed. crack. The stretching method used to obtain the stretched film may be either uniaxial stretching or biaxial stretching, but biaxial stretching is preferred. Among them, a suitable implementation type is a biaxial extension in which the stretching ratio is high in the TD direction of the material film.

Extension can be performed using well-known extension devices. Examples of the stretching device include a longitudinal uniaxial stretching machine, a tenter stretching machine, a bubble stretching machine, and a roll stretching machine.

The elongation temperature is preferably (Tg-30 ° C) or higher, (Tg-10 ° C) or higher, and (Tg + 60 ° C) or lower, and (Tg + 50 ° C) or lower. Here, "Tg" means the glass transition temperature of a resin.

The stretching ratio is preferably 1.05 to 5 times, more preferably 1.1 to 4 times, and even more preferably 1.15 to 3 times. When extending in different directions like biaxial extension, it is preferable that the total extension ratio represented by the product of the extension ratios in each extension direction falls within the aforementioned range.

[7.2. Formation of pores]

After the material film is manufactured, a hole-containing portion is formed on the surface of the material film, thereby manufacturing a viewing angle widening film.

As an example of a specific method of forming the hole-containing portion, crack processing may be mentioned. By performing the crack processing, it is possible to efficiently produce a viewing angle widening film in which a hole-containing portion is formed by cracks.

The crack processing can be performed by any method such as a known method. Examples of crack processing include Japanese Patent Publication No. H6-82607, Japanese Patent Publication No. H7-146403, Japanese Patent Publication No. H9-166702, Japanese Patent Publication No. H9-281306, and WO2007. / 046467, Japanese Patent Publication No. 2006-313262, Japanese Patent Publication No. 2009-298100, and Japanese Patent Publication No. 2012-167159.

A specific example of crack processing will be described with reference to FIGS. 3 and 4. FIG. 3 is a schematic perspective view illustrating an example of a crack processing device, and FIG. 4 is a schematic side view illustrating the vicinity of the scraper of FIG. 3 in an enlarged manner. In FIG. 4, the device is viewed from the TD direction.

In the example of FIG. 3, the crack processing apparatus 100 includes a take-up roll 41, conveyance rolls 42 and 43, and a scraper 30. The doctor blade 30 includes a cutting edge 30E extending in a direction parallel to the TD direction.

In the operation of the crack processing device 100, the material film 10 conveyed by the unwinding roller 41 in the direction of the arrow A11 passes through the conveying rollers 42 and 43 and is supported while being pressed against the blade edge 30E of the scraper 30 delivery. Thereby, pressure can be applied to the material film 10. As a result, the surface of the material film 10 is deformed due to pressure, and the hole-containing portion 20 extending in a direction slightly parallel to the TD direction can be formed, and the viewing angle widening film 1 can be manufactured.

In the crack processing, the angle at which the scraper 30 contacts the material film 10 is appropriately adjusted to an angle at which a desired crack can be formed. In the examples of FIGS. 3 and 4, this angle is expressed as an angle θ between the center line 30C of the blade 30 and the surface on the downstream side of the material film 10 as viewed from the extending direction of the cutting edge 30E. The angle θ is preferably 10 ° to 60 °, more preferably 15 ° to 50 °, and even more preferably 20 ° to 40 °.

When the doctor blade is pushed against the material film, the tension of the material film is appropriately adjusted to a value capable of forming a desired crack. The tension is preferably 100 N / m to 1000 N / m, and more preferably 300 N / m to 800 N / m.

When the material film is stretched, the crack processing may be performed before the material film is stretched, or may be performed simultaneously with the stretch processing.

In the case where a material film having two or more resin layers is used as the material film, and crack processing is performed on such a material film, cracks may occur in all of the resin layers of two or more layers, and there may be only a part of the resin layers. When cracks occur. Furthermore, in the case where cracks occur only in a part of the resin layer, there are cases where cracks occur in the outermost layer body, and in some cases, cracks occur in the inner layer body. For example, in the case of cracking a material film made of a "core layer of a material with relatively small tensile elongation and a brittle material" and "a skin layer of a material that is relatively soft on the front and back sides" Cracks may occur only in the core layer. Such a film may also be used as the viewing angle widening film of the present invention.

[8. Use of viewing angle widening film: polarizer]

The viewing angle widening film of the present invention can be used for the purpose of expanding the viewing angle of a liquid crystal display device. However, the function of the viewing angle widening film of the present invention is not limited to this. For example, the viewing angle-enlarging film of the present invention may be one that functions in addition to its functions as a viewing angle-enlarging film. Examples of functions other than such a viewing angle widening film include a function as a protective film, a function as a retardation film, and a function as an optical compensation film. In particular, as described below, it is well used as a polarizing plate that also functions as a protective film for a polarizing plate.

The polarizing plate of the present invention includes the viewing angle widening film and a polarizer of the present invention. In the polarizing plate of the present invention, the viewing angle widening film also has to function as a polarizing plate protective film. Such a polarizing plate can be manufactured, for example, by bonding a polarizer and a viewing angle widening film. In the polarizing plate of the present invention, the polarizer and the viewing angle widening film may be directly bonded without interposing a bonding layer, or may be bonded via a bonding layer formed by a bonding agent. Furthermore, there may be other protective films between the polarizer and the viewing angle widening film.

In the case where the viewing angle widening film has a hole-containing portion only on one surface, the surface may be located on the polarizer side or on the opposite side to the polarizer.

The polarizing plate of the present invention may be provided with a viewing angle expanding film only on one side of the polarizer, or may be provided on both sides. When the viewing angle widening film is provided only on one side of the polarizer, the polarizing plate may include any film other than the viewing angle widening film that functions as a protective film on the other side of the polarizer.

In the polarizing plate of the present invention, the viewing angle widening film must be directly connected to the polarizer. Alternatively, the polarizing plate of the present invention may further have another layer body existing between the viewing angle widening film and the polarizer. In the case where the viewing angle-enlarging film is connected to the polarizer directly or only through an intermediary bonding layer, the viewing angle-enlarging film has to function as a protective film for protecting the polarizer in the polarizing plate.

On the other hand, the polarizing plate and the liquid crystal display device of the present invention may be configured only by adding a viewing angle widening film to an existing liquid crystal display device. Specifically, a viewing angle-enlarging film is mounted on the display surface of a liquid crystal display device including various protective elements such as a protective film closer to the viewing side than the viewing-side polarizer, thereby combining the viewing-side polarizer and the viewing angle-enlarging film. , And constitute the polarizing plate and the liquid crystal display device of the present invention.

When the polarizing plate of the present invention is used in a VA mode liquid crystal display device described later, it is preferable that the longitudinal direction of the hole-containing portion is parallel to the absorption axis of the polarizer. Thereby, the viewing angle of the liquid crystal display device in the VA mode can be enlarged.

In addition, in the case where the polarizing plate of the present invention is used in a TN mode liquid crystal display device described later, when the display screen of the liquid crystal display device is viewed from an oblique direction, the azimuth angle of inversion of the color scale and the length direction of the hole-containing portion The angle is preferably vertical. Thereby, the viewing angle of the liquid crystal display device in the TN mode can be enlarged.

The polarizer, for example, can be manufactured by uniaxially stretching in a boric acid bath after the polyvinyl alcohol film adsorbs iodine or a dichroic dye. In addition, for example, it can also be produced by making a polyvinyl alcohol film adsorb iodine or a dichroic dye and extending it, and then further modifying a part of the polyvinyl alcohol unit in the molecular chain to a polyethylene unit. Furthermore, as the polarizer, for example, a polarizer having a function of separating polarized light into reflected light and transmitted light, such as a grid polarizer, a multilayer polarizer, and a cholesteric liquid crystal polarizer, can also be used. Among these, a polarizer made of polyvinyl alcohol is preferred. The polarization degree of the polarizer is preferably 98% or more, and more preferably 99% or more. The average thickness of the polarizer is preferably 5 μm to 80 μm.

As the bonding agent for bonding the polarizer and the viewing angle widening film, any bonding agent which is optically transparent may be used. Examples of the adhesive include water-based adhesives, solvent-based adhesives, two-liquid curable adhesives, ultraviolet-curable adhesives, and pressure-sensitive adhesives. Among them, an aqueous adhesive is preferable, and a polyvinyl alcohol-based aqueous adhesive is particularly preferable. The bonding agent may be used singly or in combination of two or more kinds at any ratio.

The average thickness of the bonding layer is preferably 0.05 μm or more, more preferably 0.1 μm or more, more preferably 5 μm or less, and even more preferably 1 μm or less.

There is no limitation on the method of bonding the viewing angle expanding film and the polarizing member, but for example, after one side of the polarizing member is coated with a bonding agent as required, a polarizer and the viewing angle expanding film are bonded using a roll laminator, and then carried out as required The drying method is preferred. The drying time and drying temperature can be appropriately selected according to the type of the bonding agent.

[9. Liquid crystal display device]

The viewing angle widening film of the present invention and the polarizing plate of the present invention can be used in a liquid crystal display device. As the liquid crystal cell constituting the liquid crystal display device, a well-known person such as TN (Twisted Nematic) mode, VA (Virtical Aligment) mode, and IPS (In-Plane Switching) mode can be used, but from the viewpoint of effectively expanding the viewing angle, TN Mode and VA mode are preferred.

[9.1. TN mode liquid crystal display device]

The viewing angle widening film of the present invention or the polarizing plate of the present invention is preferably a liquid crystal display device used in a TN mode.

The liquid crystal display device in the TN mode of the present invention is provided with the polarizing plate of the present invention and the liquid crystal cell in the TN mode in order from the viewing side. The polarizing plate is arranged in such a way that the surface of the viewing angle-enlarging film side becomes the viewing side, and is self-slanting. When the display screen of the liquid crystal display device is viewed in a direction, the azimuth angle in which the gradation is inverted is perpendicular to the angle between the length direction of the hole-containing portion. Here, the azimuth angle of inversion of the color gradation refers to a case where a polarizing plate having the same structure as the polarizing plate of the present invention is provided in addition to the viewing angle widening film of the present invention instead of the polarizing plate of the present invention for observation. The azimuth angle of the level inversion.

A TN mode liquid crystal display device generally includes a polarizing plate and a light source on a side of the TN mode liquid crystal cell opposite to the viewing side. As the polarizing plate disposed on the side opposite to the viewing side, a polarizing plate of the present invention may be used, or a polarizing plate other than the polarizing plate of the present invention such as a well-known polarizing plate may be used. Further, as the light source, an arbitrary light source such as a well-known light source may be used.

The viewing side refers to the side where the viewer of the displayed image is located when the liquid crystal display device is used.

Generally, when operating the liquid crystal display device from a black display state (a state where black is displayed on the entire screen of the device) to gradually increasing the brightness to a white display state (a state where white is displayed on the entire screen of the device), The brightness will gradually rise. For example, operate in such a way that the display screen of the liquid crystal display device displays 8-bit gray levels (the black display state is set to 0, the white display state is set to 255, and the intermediate color level is represented by values from 0 to 255) When the level is increased from 0 to 255, the brightness of the display screen also increases. However, depending on the direction of observation, the brightness of the display screen may decrease, although the brightness is gradually increased. In this way, the operation of increasing or decreasing the brightness displayed by the display device does not coincide with the actual increase or decrease of the brightness of the display screen, which is called "gradation inversion". The gradation inversion is sometimes seen at a certain azimuth when viewing the display screen of the liquid crystal display device from an oblique direction. According to the TN mode liquid crystal display device of the present invention, the angle between the azimuth angle of the gradation inversion when viewing the display screen from the oblique direction and the angle between the length direction of the hole-containing portion is perpendicular, which can reduce such gradation inversion To expand perspective.

The azimuth angle of the inversion of the color scale is not limited to a single direction, and there may be two directions or an angular range with a certain degree of breadth. In this case, it is necessary to set the direction in which the viewing angle is most desired, and set the length direction of the hole-containing portion to be a direction perpendicular to the direction.

In the TN mode liquid crystal display device of the present invention, as the polarizing plate of the present invention, the angle between the absorption axis of the polarizer and the length direction of the hole-containing portion is preferably 45 °. In a normal TN mode liquid crystal display device (a user who has a rectangular display screen and the display screen is erected in a slightly vertical direction, the long side direction of the rectangle becomes a horizontal direction, and the short side direction becomes a slightly vertical direction) , When viewing from the lower side, it is often seen that the gradation is reversed. Moreover, in a normal TN mode liquid crystal display device, the angle between the absorption axis of the polarizer and the horizontal direction of the display screen is often 45 °. Therefore, in the case where the angle between the absorption axis of the polarizer and the length direction of the hole-containing portion is 45 ° as the polarizing plate of the present invention, it is easy to sandwich the absorption axis of the polarizer with the horizontal direction of the display screen. The angle is 45 °, and the length direction of the hole-containing portion is parallel to the angle between the horizontal direction of the display screen. Therefore, the viewing angle of the TN mode liquid crystal display device can be easily expanded.

[9.2. Liquid crystal display device in VA mode]

The viewing angle widening film of the present invention or the polarizing plate of the present invention is preferably a liquid crystal display device used in a VA mode.

The liquid crystal display device of the VA mode of the present invention is provided with the polarizing plate of the present invention and the liquid crystal cell of the VA mode in order from the viewing side, and the polarizing plate is arranged in such a way that the surface of the viewing angle widening film side becomes the viewing side.

A liquid crystal display device in the VA mode usually includes a polarizing plate and a light source on a side of the liquid crystal cell of the VA mode opposite to the viewing side. As the polarizing plate disposed on the side opposite to the viewing side, a polarizing plate of the present invention may be used, or a polarizing plate other than the polarizing plate of the present invention such as a well-known polarizing plate may be used. Further, as the light source, an arbitrary light source such as a well-known light source may be used.

In the liquid crystal display device of the VA mode of the present invention, as the polarizing plate of the present invention, it is good to use the length direction of the hole-containing portion parallel or perpendicular to the absorption axis of the polarizer. In a case where such a polarizing plate is arranged in a general liquid crystal display device, the relationship between the length direction of the hole-containing portion and the long side direction of the display screen is preferably parallel or perpendicular. The length direction of the hole-containing portion may be adjusted to be perpendicular to the azimuth direction in which the viewing angle is required to be enlarged. For example, in a case where a display device having a rectangular display screen is required to widen the viewing angle in the long side direction, the length direction of the hole-containing portion is preferably arranged in a direction parallel to the short side direction. The length direction of the hole-containing portion is usually adjusted to be parallel or perpendicular to the absorption axis of the polarizer. By making such an arrangement, the viewing angle of the VA mode liquid crystal display device can be enlarged.

『Examples』

The following examples are disclosed to illustrate the present invention in detail. However, the present invention is not limited to the following embodiments, and can be implemented with arbitrary changes without departing from the scope of the patent application of the present invention and its equivalent scope.

In the following description, "%" and "parts" indicating amounts are based on weight unless otherwise noted. Unless otherwise noted, the following operations are performed in normal temperature and pressure atmosphere.

[Evaluation method]

(Comparison and Δγ)

Contrast and Δγ were measured for the liquid crystal display devices of the examples and comparative examples.

For measurement, a spectroradiometer (manufactured by Topcon, product name "SR-LEDW") was used. Contrast is measured from the front direction (polar angle 0 °) of the display device. During the measurement, the illuminance of the light irradiated to the display surface of the device is set to 0 Lux. Measure the brightness in the white display state and the brightness in the black display state, and find the ratio of (brightness in the white display state) / (brightness in the black display state) as a comparison. High contrast means good contrast.

In addition, the colors of each of the gradations of 0 (black) to 255 (white) among 256 gradations are displayed, and the brightness is observed from the front direction and the polar angle of 75 °. The azimuth in the direction of the polar angle of 75 ° was adjusted to the in-plane direction of the display device perpendicular to the length direction of the hole-containing portion. In the embodiment, the in-plane direction of the display device perpendicular to the length direction of the hole-containing portion is adjusted, while in the comparative example, the in-plane direction of the display device corresponding to each embodiment is adjusted. In the observation in all directions, the normalized brightness where the brightness at the gray level 0 is 0% and the brightness at the gray level 255 is calculated is calculated, and the relationship between the gray scale and the normalized brightness is calculated. The absolute value of the difference between the normalized brightness in the front direction and the normalized brightness in the polar angle of 75 ° is obtained in each of the gray scales, and the maximum value among these values is obtained as Δγ (%). Low Δγ indicates good viewing angle characteristics.

(Δγ after moisture resistance test)

A humidity resistance test was performed for 500 hours when the viewing angle-enlarging films obtained in the examples and comparative examples were stored in an environment having a temperature of 60 ° C. and a humidity of 90%. A liquid crystal display device was manufactured using the viewing angle widening film after the humidity resistance test, and then the Δγ of the liquid crystal device was measured by the aforementioned method.

(Δγ after heat resistance test)

A heat resistance test was performed in which the viewing angle widening films obtained in the examples and comparative examples were stored in an environment at a temperature of 85 ° C. for 500 hours. A liquid crystal display device was produced using the viewing angle widening film after the heat resistance test, and then the Δγ of the liquid crystal device was measured by the method described above.

[Production Example 1] Production of norbornene-based polymer 1

In a polymerization reactor that has been dried and replaced with nitrogen, 2.0 parts of a monomer mixture (relative to polymerization) consisting of 70% tetracyclododecene, 10% dicyclopentadiene, and 20% methyltetrahydropyrene was charged. The total amount of monomers used is 1%), 785 parts of dehydrated cyclohexane, 1.21 parts of molecular weight regulator (1-hexene), n-hexane solution of diethylethoxyaluminum (concentration: 19%) 0.98 Parts, and 11.7 parts of a toluene solution (concentration: 2.0%) of (phenylphenylimino) tungsten / tetrahydrofuran in tetrachloride, and stirred at 50 ° C for 10 minutes.

Subsequently, while maintaining the whole at 50 ° C. while stirring, 198.0 parts of the monomer mixture having the same composition as above was continuously dropped in the aforementioned polymerization reactor over a period of 150 minutes. After stirring was continued for 30 minutes after the completion of the dropping, 4 parts of isopropanol was added to terminate the polymerization reaction. As a result of analyzing the polymerization reaction solution by gas chromatography, the conversion ratio of the monomer to the polymer was 100%.

Subsequently, 300 parts of the obtained polymerization reaction solution was transferred to an autoclave with a stirrer, and 32 parts of cyclohexane and a diatomite-supported nickel catalyst (manufactured by Nichiwa Chemical Co., Ltd .; "T8400RL", nickel bearing rate 58) were added. %) 3.8 copies. After replacing the inside of the autoclave with hydrogen, it was allowed to react at 190 ° C and a hydrogen pressure of 4.5 MPa for 6 hours.

After the hydrogenation reaction was completed, diatomaceous earth ("Radiolite (registered trademark) # 500") was used as a filter bed, and a pressure filter (manufactured by Ishikawajima Harima Heavy Industries Co., Ltd .; "FUNDA Filter") was used for pressure filtration at a pressure of 0.25 MPa. A colorless and transparent solution was obtained. To this solution, 0.5 part of {3- [3,5-bis (tertiarybutyl) -4-hydroxyphenyl] propanoic acid} neopentaerythritol (Ciba Specialty Chemicals) was added per 100 parts of polymer hydride. Made by the company, with the product name "Irganox (registered trademark) 1010") as an antioxidant, then a filter (manufactured by CUNO Filter; "Zeta Plus (registered trademark) 30H", pore diameter 0.5 to 1 μm) and a metal fiber filter (NICHIDAI) (Manufactured by the company, with a pore diameter of 0.4 μm).

Subsequently, the filtrate obtained above was placed in a cylindrical concentration dryer (manufactured by Hitachi, Ltd.), and cyclohexane and other volatile components were removed as a solvent at a temperature of 290 ° C and a pressure of 1 kPa or less. A die directly connected to the thickener was extruded into a strand shape in a molten state, cooled with water, and then cut with a granulator (manufactured by Nagada Manufacturing Co., Ltd .; "OSP-2") to obtain pellets.

As a result of analyzing particles by gel permeation chromatography (GPC), the hydrogenation rate in the hydrogenation reaction was more than 99%, the weight average molecular weight was 26,000, and the number average molecular weight was 19,000.

[Example 1]

(1-1. Preparation of material film)

A multilayer film having a two-layer, two-layer structure of a skin layer and a core layer was prepared as a material film. As the material of the skin layer, a resin film 1 (trade name: ZeonorFilm, manufactured by Rihon Co., Ltd., glass transition temperature of 126 ° C, and thickness of 48 μm) containing a norbornene-based polymer (referred to as "COP" in the table) was used. . As the material of the core layer, the norbornene-based polymer 1 and hydrogenated C9-based petroleum resin 1 (trade name: ARKON P140, manufactured by Arakawa Chemical Industries, Ltd.) manufactured in Production Example 1 were used, and the number average molecular weight was 940, softened. Point: 140 ± 5 ℃).

On one side of the resin film 1, a coating liquid 1 containing a material of a core layer (a norbornene-based polymer 1 and a hydrogenated C9-based petroleum resin 1) was applied using a die coater. The coating liquid 1 was prepared by stirring 14.25 parts of a norbornene-based polymer 1 and 0.75 parts of a hydrogenated C9-based petroleum resin 1 together with 85 parts of cyclohexane for 24 hours. The coating amount of the coating liquid 1 was adjusted so that the thickness of the core layer after drying was 6 μm.

The resin film 1 to which the coating liquid 1 was applied was dried in an oven at 85 ° C. for 5 minutes to obtain a material film. The obtained material film has a width of 300 mm, the thickness of the skin layer is 48 μm, and the thickness of the core layer is 6 μm. The glass transition temperature of the resin constituting the core layer was 148 ° C. The proportion of hydrogenated C9-based petroleum resin 1 (hydrocarbon) in the resin constituting the core layer was 5%.

(1-2. Viewing angle expanding film)

3 and 4 were used to manufacture a viewing angle widening film. In the apparatus, as the scraper 30, a SUS scraper (the front end of the scraper R = 0.2 mm) was used.

The material film obtained in (1-1) is arranged such that the surface of the core layer side thereof contacts the scraper blade 30, and the material film 10 is pushed against the scraper blade 30 under a tension of 500 N / m, It was transported at a speed of 50 mm / min in the direction of arrow A11 to perform crack processing.

During crack processing, the direction of the edge 30E of the scraper 30 is adjusted to the width direction (TD direction) of the material film. The angle θ between the center line 30C of the scraper 30 and the surface on the downstream side of the material film 10 as viewed from the extension direction of the cutting edge 30E was adjusted to 20 °. The crack-processed film was uniaxially stretched in the MD direction (1.2 times the uniaxial extension of the fixed end), and a viewing angle-enlarging film with a thickness of 40 μm for the skin layer and 5 μm for the core layer was manufactured. Three viewing angle expansion films were produced, one of which was mounted on a liquid crystal display device, and the other two were mounted on a liquid crystal display device after being subjected to a humidity resistance test and a heat resistance test, respectively.

The hole-containing portion of the obtained viewing angle-enlarging film appears on the core layer side. The pore-containing portion is a crack having a substantially linear shape, and the length directions of the pore-containing portion are slightly parallel to each other and slightly parallel to the TD direction of the film. The interval P including the pores is an indefinite interval of 23 μm or less. The average value of the width of each hole-containing portion was 5.4 μm, and the average value of the depth of the hole-containing portion (height of the hole) was 5 μm. These equivalent values were obtained by selecting three arbitrary places of the cracked film and observing an area of 25 μm square with a scanning electron microscope.

(1-3. Manufacturing of liquid crystal display device)

A polarizing plate on the viewing side surface of a linearly polarized VA mode liquid crystal display device (27 inches by BenQ, model GW2760HS) was bonded to the viewing angle widening film obtained in (1-2). During lamination, the angle between the absorption axis of the polarizer in the viewing side polarizer and the length direction of the hole-containing portion of the viewing angle expansion film becomes 90 °, and the length direction of the hole-containing portion is relative to the rectangular display screen. The direction of the short sides becomes parallel, and adjust these directions. In addition, the viewing angle widening film is bonded so that the surface on the side where the hole-containing portion is formed becomes the viewing side. Thereby, the liquid crystal display device of the present invention is obtained.

(1-4. Evaluation)

Measurement comparison and Δγ for the liquid crystal display device obtained in (1-3). In addition, Δγ was measured separately for “a liquid crystal display device manufactured using a viewing angle expanding film after a humidity resistance test” and “a liquid crystal display device manufactured using a viewing angle expanding film after a heat resistance test”.

[Example 2]

A liquid crystal display device and its constituent elements were obtained and evaluated by the same operation as in Example 1 except for the following changes.
・ In the preparation of the material film of (1-1), the coating liquid 2 is used instead of the coating liquid 1, which is a mixture of 12 parts of a norbornene polymer 1 and 3 parts of a hydrogenated C9 petroleum resin 1 It was prepared by stirring with 85 parts of cyclohexane for 24 hours. The glass transition temperature of the resin constituting the core layer was 135 ° C. The proportion of hydrogenated C9 petroleum resin 1 (hydrocarbon) in the resin constituting the core layer is 20%.

The hole-containing portion of the viewing angle widening film obtained in Example 2 appeared in the core layer. The pore-containing portion is a crack having a substantially linear shape, and the length directions of the pore-containing portion are slightly parallel to each other and slightly parallel to the TD direction of the film. The interval P including the pores is an indefinite interval of 26 μm or less. The average value of the width of each hole-containing portion is 6.2 μm, and the average value of the depth (height) of the hole-containing portion is 5 μm.

[Example 3]

A liquid crystal display device and its constituent elements were obtained and evaluated by the same operation as in Example 1 except for the following changes.
・ In the preparation of the material film of (1-1), the coating liquid 3 is used instead of the coating liquid 1, which is 10.5 parts of a norbornene-based polymer 1 and 4.5 parts of a hydrogenated C9-based petroleum resin 2 ( Trade name: ARKON P90, manufactured by Arakawa Chemical Industries, Ltd., number average molecular weight 590, softening point: 90 ± 5 ° C)) and 85 parts of cyclohexane were prepared by stirring for 24 hours. The glass transition temperature of the resin constituting the core layer was 120 ° C. The proportion of hydrogenated C9-based petroleum resin 2 (hydrocarbon) in the resin constituting the core layer is 30%.

The hole-containing portion of the viewing angle widening film obtained in Example 3 appeared in the core layer. The pore-containing portion is a crack having a substantially linear shape, and the length directions of the pore-containing portion are slightly parallel to each other and slightly parallel to the TD direction of the film. The interval P including the pores is an indefinite interval of 30 μm or less. The average value of the width of each hole-containing portion is 7.2 μm, and the average value of the depth (height) of the hole-containing portion is 5 μm.

[Example 4]

A liquid crystal display device and its constituent elements were obtained and evaluated by the same operation as in Example 1 except for the following changes.
・ In the preparation of the material film of (1-1), coating liquid 4 is used instead of coating liquid 1, which is based on 12 parts of norbornene polymer 1 and 3 parts of hydrogenated DCPD / C9 petroleum resin. (Trade name: T-REZ HB125, manufactured by JXTG Energy Co., Ltd., number average molecular weight: 430, softening point: 124.6 ° C) and 85 parts of cyclohexane were prepared by stirring for 24 hours. The glass transition temperature of the resin constituting the core layer was 130 ° C. The proportion of hydrogenated DCPD / C9 based petroleum resin (hydrocarbon) in the resin constituting the core layer is 20%.

The hole-containing portion of the viewing angle widening film obtained in Example 4 appeared in the core layer. The pore-containing portion is a crack having a substantially linear shape, and the length directions of the pore-containing portion are slightly parallel to each other and slightly parallel to the TD direction of the film. The interval P including the pores is an indefinite interval of 25 μm or less. The average value of the width of each hole-containing portion is 6.0 μm, and the average value of the depth (height) of the hole-containing portion is 5 μm.

[Example 5]

A liquid crystal display device and its constituent elements were obtained and evaluated by the same operation as in Example 1 except for the following changes.
・ In the preparation of the material film of (1-1), the coating liquid 5 is used instead of the coating liquid 1, which is based on 12 parts of the norbornene polymer 1 and 3 parts of the DCPD / aromatic copolymerization system. Hydrogenated petroleum resin (trade name: I-MARV P140, manufactured by Idemitsu Kosan Co., Ltd., number average molecular weight: 900, softening point: 140 ° C), and 85 parts of cyclohexane were prepared by stirring for 24 hours. The glass transition temperature of the resin constituting the core layer was 135 ° C. The proportion of DCPD / aromatic copolymerized hydrogenated petroleum resin (hydrocarbon) in the resin constituting the core layer is 20%.

The hole-containing portion of the viewing angle widening film obtained in Example 5 appeared in the core layer. The pore-containing portion is a crack having a substantially linear shape, and the length directions of the pore-containing portion are slightly parallel to each other and slightly parallel to the TD direction of the film. The interval P including the pores is an indefinite interval of 25 μm or less. The average value of the width of each hole-containing portion is 6.0 μm, and the average value of the depth (height) of the hole-containing portion is 5 μm.

[Comparative Example 1]

A liquid crystal display device and its constituent elements were obtained and evaluated by the same operation as in Example 1 except for the following changes.
In the preparation of the material film of (1-1), an acrylic resin film C1 is used instead of the resin film 1 as the material of the skin layer. The acrylic resin film C1 (referred to as "PMMA" in Table 2) is formed by using an acrylic resin (trade name: HT55X, manufactured by Sumitomo Chemical Co., Ltd., glass transition temperature: 108 ° C) containing an acrylic polymer and rubber particles to form the film A film having a thickness of 48 μm was obtained.
・ In the preparation of the material film of (1-1), coating liquid C1 is used instead of coating liquid C1, which is a polymethyl methacrylate resin (trade name: Delpet 980N, manufactured by Asahi Kasei Corporation, methyl A copolymer of methyl acrylate / styrene / maleic anhydride, glass transition temperature (118 ° C), 15 parts, and 85 parts of acetone were stirred for 24 hours to prepare. The glass transition temperature of the resin constituting the core layer was 118 ° C.

The hole-containing portion of the viewing angle widening film obtained in Comparative Example 1 appeared in the core layer. The pore-containing portion is a crack having a substantially linear shape, and the length directions of the pore-containing portion are slightly parallel to each other and slightly parallel to the TD direction of the film. The interval P including the pores is an indefinite interval of 23 μm or less. The average value of the width of each hole-containing portion is 5.4 μm, and the average value of the depth (height) of the hole-containing portion is 5 μm.

[Comparative Example 2]

A liquid crystal display device and its constituent elements were obtained and evaluated by the same operation as in Example 1 except for the following changes.
In the preparation of the material film of (1-1), the above-mentioned acrylic resin film C1 is used instead of the resin film 1 as the material of the skin layer.
・ In the preparation of the material film of (1-1), coating liquid C2 is used instead of coating liquid C2, which is a polymethylmethacrylate polymer resin (trade name: Delpet 80NH, manufactured by Asahi Kasei Corporation , Glass transition temperature 100 ° C) 15 parts together with 85 parts of acetone and stirred for 24 hours to prepare. The glass transition temperature of the resin constituting the core layer was 100 ° C.

The hole-containing portion of the viewing angle widening film obtained in Comparative Example 2 appeared in the core layer. The pore-containing portion is a crack having a substantially linear shape, and the length directions of the pore-containing portion are slightly parallel to each other and slightly parallel to the TD direction of the film. The interval P including the pores is an indefinite interval of 26 μm or less. The average value of the width of each hole-containing portion is 6.2 μm, and the average value of the depth (height) of the hole-containing portion is 5 μm.

[Comparative Example 3]

A liquid crystal display device and its constituent elements were obtained and evaluated by the same operation as in Example 1 except for the following changes.
・ In the preparation of the material film of (1-1), the coating liquid C3 is used instead of the coating liquid C. The coating liquid C3 is obtained by stirring 15 parts of the norbornene polymer 1 together with 85 parts of cyclohexane for 24 hours. preparation. The glass transition temperature of the resin constituting the core layer was 153 ° C.

As a result of cracking the thin film of the material obtained in Comparative Example 3, no holes (cracks) appeared in the skin layer and the core layer.

The results of the examples and comparative examples are shown in Tables 1 and 2. "Δγ" in a table | surface shows the result of Δγ of the liquid crystal display device provided with the viewing angle expansion film which did not perform the heat resistance test and the humidity resistance test. The "Δγ after the moisture resistance test" in the table indicates the results of the Δγ of the liquid crystal display device including the viewing angle widening film subjected to the humidity resistance test. The "Δγ after the heat resistance test" in the table indicates the result of the Δγ of the liquid crystal display device including the viewing angle widening film subjected to the heat resistance test.

"Table 1"

"Table 2"

From the results disclosed in Tables 1 and 2, it is apparent that in the examples using the "view-angle widening film of the present invention having a pore-containing layer composed of a resin containing an alicyclic structure polymer and a hydrocarbon", the comparison exceeded In 2000, Δγ after the moisture resistance test and Δγ after the heat resistance test were the same as Δγ before the humidity resistance test and the heat resistance test. In short, in the embodiment using the viewing angle expanding film of the present invention, a liquid crystal display device having good characteristics of "good contrast and excellent viewing angle expansion characteristics even after being arranged in a high humidity environment and a high temperature environment" was obtained.

1‧‧‧ viewing angle expansion film

10‧‧‧ film

20‧‧‧ with holes

21‧‧‧ Crack (including hole)

211‧‧‧fibril

212‧‧‧hole

100‧‧‧Crack processing device

30‧‧‧Scraper

<FIG. 1> FIG. 1 is a schematic plan view showing an example of a viewing angle widening film.

<Fig. 2> Fig. 2 is an enlarged schematic diagram showing an example of a cracked structure.

<Fig. 3> Fig. 3 is a schematic perspective view showing an example of a crack processing device.

<Fig. 4> Fig. 4 is a schematic side view of an enlarged drawing of the vicinity of the scraper of Fig. 3.

Claims (15)

A viewing angle expanding film is a viewing angle expanding film for expanding the viewing angle, wherein the viewing angle expanding film includes one or more resin layers, one or more of the resin layers are pore-containing layers, and the pore-containing layers are provided with a plurality of each other slightly. The pore-containing portions are parallel, the pore-containing portions contain pores, and the resin constituting the pore-containing layer includes an alicyclic structure-containing polymer and a hydrocarbon, and the number average molecular weight of the hydrocarbon is 200 to 1500. The viewing angle widening film according to claim 1, wherein the glass transition temperature (Tg) of the resin constituting the pore-containing layer is 115 ° C or higher. The viewing angle widening film according to claim 1 or 2, wherein the hydrocarbon is a hydrogenated petroleum resin. The viewing angle widening film according to claim 1 or 2, wherein the aforementioned hydrocarbon has a softening point of 90 ° C to 150 ° C and is selected from hydrogenated C9-based petroleum resin and hydrogenated dicyclopentadiene-based petroleum resin. More than that. The angle-expanding film according to claim 1 or 2, wherein the alicyclic structure-containing polymer is selected from the group consisting of a norbornene polymer, a monocyclic cyclic olefin polymer, a cyclic conjugated diene polymer, and ethylene Alicyclic hydrocarbon polymers and polymers of these hydrides. The viewing angle widening film according to claim 1 or 2, which includes two or more resin layers. The viewing angle widening film according to claim 1 or 2, wherein an interval between the adjacent pore-containing portions is an indefinite interval of 50 μm or less. The viewing angle widening film according to claim 1 or 2, which contains an ultraviolet absorber. The viewing angle widening film according to claim 1 or 2, wherein the viewing angle widening film is a polarizing plate protective film. The viewing angle widening film according to claim 1 or 2, wherein the hole-containing portion is formed by cracks. A polarizing plate comprising the viewing angle widening film and a polarizer according to any one of claims 1 to 10. The polarizing plate according to claim 11, wherein a length direction of the hole-containing portion is parallel or perpendicular to an absorption axis of the polarizer. The polarizing plate according to claim 11, wherein the angle between the absorption axis of the polarizer and the length direction of the hole-containing portion is 45 °. A TN mode liquid crystal display device is a TN mode liquid crystal display device sequentially provided with a polarizing plate as described in claim 11 or 13 and a TN mode liquid crystal cell from the viewing side, wherein the aforementioned polarizing plate is at its aforementioned viewing angle. The surface on the enlarged film side is arranged as a viewing side, and when the display screen is viewed from an oblique direction, the azimuth angle in which the gradation is inverted is perpendicular to the angle between the longitudinal direction of the hole-containing portion. A VA mode liquid crystal display device is a VA mode liquid crystal display device sequentially provided with a polarizing plate as described in claim 11 or 12 and a VA mode liquid crystal cell from the viewing side, wherein the aforementioned polarizing plate is at its aforementioned viewing angle. The surface on the enlarged film side is arranged as a viewing side, and the longitudinal direction of the hole-containing portion is parallel to the absorption axis of the polarizer.