JP2007293314A - Film, film manufacturing method, and use thereof - Google Patents

Abstract

The present invention provides a film capable of giving a high refractive index not in the plane direction of the film of the optical film but in the normal direction of the film, a method for producing the film, and use thereof.
A layer of a hybrid alignment rod-like polymerizable liquid crystal compound is formed on an alignment film for vertical alignment. At this time, the rod-like polymerizable liquid crystal compound is vertically aligned or tilted at the interface of the alignment film for vertical alignment. As a result, a film satisfying nz> nx and nz> ny can be produced when the refractive indexes in the orthogonal axis direction and the film thickness direction of the film plane are nx, ny, and nz, respectively.
[Selection figure] None

Description

  The present invention relates to a film, a film manufacturing method, and use thereof, and can provide a high refractive index in the normal direction of the film, not in the plane direction of the film, and the film manufacturing method, It is about use.

  Flat panel display devices (hereinafter also referred to as “FPD”) such as liquid crystal display devices (hereinafter also referred to as “LCD”) and organic electroluminescence (hereinafter also referred to as “EL”) are less space-consuming than CRTs. Low power consumption. Therefore, in recent years, FPD has been widely used as a screen of a computer, a television, a mobile phone, a car navigation, or a portable information terminal.

  In general, various optical films are used for FPD in order to prevent reflection and widen the viewing angle. For example, an anti-reflection film such as an anti-reflection (hereinafter also referred to as “AR”) film that reduces the reflectance of the surface by the optical interference effect by layering optical thin film layers having different refractive indexes, only light in a specific vibration direction Polarizing film that transmits and blocks other light, retardation film that optically compensates for interference color of LCD such as STN method and TN method, elliptically polarizing film that integrates polarizing film and retardation film, and LCD And a viewing angle widening film for enlarging the viewing angle.

  In addition, the characteristics required for the optical film used for the FPD are not only different depending on the function as described above, but are also different depending on the type of FPD to be applied. For example, an optical compensation film provided for developing a wide viewing angle in an LCD will be described below as an example. For LCDs, various liquid crystal driving methods such as VA mode, TN mode, and IPS mode have been proposed. Different characteristics are required for the optical compensation film provided for developing a wide viewing angle in the LCDs of these drive systems.

  Specifically, in a VA mode LCD, optical compensation can be performed with a stretched film whose refractive index is changed in the plane direction. As the stretched film, a film conventionally used as a retardation film that gives an optical compensation effect can be used. The stretched film can be obtained, for example, by stretching a film such as polyvinyl alcohol or polycarbonate.

  In order to develop a wide viewing angle in a TN mode LCD, it is preferable to use an optical film whose refractive index is changed in an oblique direction. Examples of such a film include a WV film (trade name) manufactured by Fuji Photo Film Co., Ltd. and an NH film (trade name) manufactured by Nippon Oil Corporation. These films are not stretched films, but optical compensation films that utilize the tilted orientation of liquid crystal molecules. As the liquid crystal molecules, tilted alignment liquid crystal molecules that are horizontally aligned at the alignment film interface and vertically aligned at the air interface are used. Thereby, the obtained film turns into a film which changed the refractive index in the diagonal direction.

  On the other hand, in order to develop a wide viewing angle in an IPS mode LCD, an optical compensation film in which the refractive index change is small in the plane direction of the film and the refractive index is changed in the normal direction is necessary. In other words, there is a need for a film that can control the tilt angle of the optically anisotropic layer, the so-called refractive index ellipsoid, in the normal direction.

  However, although the stretched film described above can increase the refractive index in the plane direction of the film, it cannot increase the refractive index in the normal direction of the film. For example, in a polycarbonate film or the like, the refractive index can be increased in the stretching direction, but the refractive index cannot be increased in the normal direction of the film. Therefore, with such a stretched film, a wide viewing angle can be realized in a VA mode LCD, but a wide viewing angle cannot be realized in a TN mode or IPS mode LCD.

  In the case of the optical compensation film using the liquid crystal molecules described above, a rubbing treatment is performed to align the liquid crystal molecules. Therefore, the liquid crystal molecules are horizontally aligned at the alignment film interface. Therefore, when liquid crystal molecules that are horizontally aligned at the alignment film interface and horizontally or vertically aligned at the air interface are used, the obtained optical compensation film is horizontally aligned and tilted aligned. Therefore, as described above, it can be used for widening the field of view of a TN mode LCD, but cannot be used for an IPS mode LCD.

  As described above, the optical compensation film used in the VA mode or TN mode LCD cannot be used to realize a wide viewing angle of the IPS mode LCD. For this reason, several optical compensation films that can cope with the wide field of view of IPS mode LCDs have been proposed.

  Specifically, in Patent Document 1, a vertical alignment film is formed using a long-chain alkyl-type dendrimer derivative, and the liquid crystal compound is homeotropically aligned by applying a polymerizable liquid crystal compound on the vertical alignment film. Also disclosed is a homeotropic alignment liquid crystal film. The polymerizable liquid crystal compound is a liquid crystal compound having, for example, an acrylate group or a methacrylate group as a polymerizable functional group. As the liquid crystal compound, a nematic liquid crystal compound may be used at room temperature. Are listed. Furthermore, it is described that the nematic liquid crystal material used here is coated on an alignment film together with a photopolymerization initiator to form a homeotropic alignment liquid crystal layer.

  In Patent Document 2, a side chain type liquid crystal polymer is applied on a substrate not provided with a vertical alignment film, and the liquid crystal polymer is homeotropically aligned in a liquid crystal state, and then the alignment state is maintained. A homeotropic alignment liquid crystal film fixed in a state is disclosed. The side chain type liquid crystal polymer contains a monomer unit having a liquid crystalline fragment containing a monomer unit (a) containing a liquid crystalline fragment side chain and a monomer unit (b) containing a non-liquid crystalline fragment side chain. It is described to do.

  Patent Document 3 discloses an optical element having a light-transmitting base material and a first birefringence layer formed on the base material. Further, it is disclosed that the first birefringent layer is made of a crosslinked polymer obtained by homeotropic alignment of a rod-like polymerizable liquid crystal containing a coupling agent. Furthermore, in the optical element, it is described that the crosslinked polymer has a structure in which a polymerizable liquid crystal having a rod-like molecular shape is three-dimensionally crosslinked while maintaining a homeotropic alignment state.

Patent Document 4 discloses an optical element having a light-transmitting base material, a vertical alignment film formed on the base material, and a first birefringence layer formed on the vertical alignment film. Is disclosed. Further, it is disclosed that the vertical alignment film is formed of a surfactant having a long chain alkyl group. Further, it is described that the first birefringence layer has a structure in which a polymerizable liquid crystal having a rod-like molecular shape is three-dimensionally cross-linked while maintaining a homeotropic alignment state.
JP 2002-174724 A (published June 21, 2002) JP 2002-174725 A (published on June 21, 2002) JP 2005-165240 A (published June 23, 2005) JP 2005-165239 A (published June 23, 2005)

  However, the vertical alignment film of the homeotropic alignment liquid crystal film of Patent Document 1 is formed of a long-chain alkyl type dendrimer derivative. This long-chain alkyl dendrimer derivative is a special material and has a problem that it is difficult to produce. Moreover, since the liquid crystal used in Patent Document 1 is homeotropically aligned on the vertical alignment film, the alignment angle of the liquid crystal molecules cannot be adjusted. Therefore, the inclination angle of the refractive index ellipsoid in the optical anisotropic layer with respect to the film plane cannot be controlled, and the viewing angle cannot be improved in accordance with the characteristics of the liquid crystal panel.

  Further, in the production of the homeotropic alignment liquid crystal film of Patent Document 2, a liquid crystal polymer is used. In the case of a liquid crystal polymer, in order to obtain a monodomain homeotropic liquid crystal alignment, the liquid crystal polymer needs to be in a liquid crystal state, and heating at a high temperature is necessary in the liquid crystal alignment step. Therefore, it is necessary to select a substrate that can withstand the heat treatment, and a film having low heat resistance cannot be used. Moreover, since the fluidity of the liquid crystal compound is increased by raising the temperature, the adhesion to the base is lowered, or the birefringence characteristics are significantly lowered due to residual stress.

  Even if the birefringent layer of the optical element of Patent Document 3 is not on the vertical alignment film, it forms homeotropic alignment. Therefore, in order to obtain homeotropic alignment, it is necessary to mix a coupling agent in addition to the rod-like polymerizable liquid crystal. However, the birefringence anisotropy of the coupling agent is smaller than that of the rod-like polymerizable liquid crystal. Therefore, there is a problem that the phase difference value of the obtained optical element is lowered. Therefore, in order to obtain a desired retardation value in the optical element, it is necessary to make the film thickness thicker than when only a rod-shaped polymerizable liquid crystal is used. Such an optical element has a problem that the weight cannot be sufficiently reduced. Furthermore, due to the influence of the coupling agent, the wettability to the base material also changes, so that the problem of repelling or lowering the adhesion to the base tends to occur.

  Furthermore, in the optical element of Patent Document 4, the vertical alignment film is formed of a surfactant. The surfactant only covers the surface of the substrate. Therefore, the vertical alignment film is very fragile and has a problem that it cannot withstand a process such as rubbing. In addition, since the vertical alignment film is formed of a surfactant, there is a problem that the adhesion with the birefringent layer made of a rod-like polymerizable liquid crystal compound is lacking.

  As described above, the conventional optical compensation film that can be applied to the wide field of view of the IPS mode has various problems, and further development of a suitable optical compensation film is required.

  In particular, in recent years, the size of FPDs has been increased, and problems due to optical films have newly occurred. Specifically, when the FPD is enlarged, when the entire display screen is observed from a wide angle, the display image is colored (also referred to as a coloring phenomenon) or black and white is reversed (also referred to as an inversion phenomenon). Occurs. Further, when the viewing angle is tilted in the counter-viewing angle direction, which is the upper direction of the display screen, there arises a problem that the contrast is lowered. Therefore, in order to solve such problems, it is required to provide an optical film that gives optical anisotropy in an arbitrary direction without much trial and error. Furthermore, in such an optical film, in addition to the optical compensation effect and the antireflection function, improvement in viewing angle dependency and further improvement in the coloring phenomenon are also required.

  The present invention has been made in view of the above problems, and is capable of providing a high refractive index in the normal direction of the film, not in the horizontal direction of the film of the optical film, and a method for producing the film, and use thereof Is to provide.

  As a result of intensive studies in view of the above-mentioned problems, the present inventors have formed a layer of a hybrid-oriented rod-like polymerizable liquid crystal compound on a vertical alignment film, whereby the refractive index has changed in the normal direction. Has been found uniquely and the present invention has been completed. That is, the present invention includes the following industrially useful inventions.

  (1) A film having an optically anisotropic layer formed on an alignment film for vertical alignment, wherein the optically anisotropic layer contains a polymer containing a structural unit derived from a rod-like polymerizable liquid crystal compound The rod-like polymerizable liquid crystal compound has a property of being oriented horizontally on a horizontal orientation film as a monomer and perpendicularly oriented at an air interface, in the direction of the perpendicular axis of the film plane and in the film thickness direction. A film characterized by satisfying nz> nx and nz> ny when the refractive indexes are nx, ny, and nz, respectively.

  (2) The film according to (1), wherein the alignment film for vertical alignment is a vertical alignment film.

  (3) The film according to (2), wherein an inclination angle of the refractive index ellipsoid in the optically anisotropic layer with respect to the film plane is 90 ± 5 °.

  (4) The film according to (1), wherein the alignment film for vertical alignment is an alignment film obtained by rubbing the vertical alignment film.

  (5) The film according to (4), wherein the refractive index ellipsoid in the optically anisotropic layer has an inclination angle with respect to the film plane of 45 ° to 85 °.

  (6) A film having an optically anisotropic layer formed on an alignment film for vertical alignment, the optically anisotropic layer comprising a layer containing a rod-like polymerizable liquid crystal compound, and the rod-like polymerizable liquid crystal The compound has the property of being oriented horizontally on the horizontal orientation film and oriented vertically at the air interface, and having refractive indexes in the orthogonal axis direction and the film thickness direction of the film plane as nx, ny, nz, In this case, the film satisfies nz> nx and nz> ny.

  (7) The film according to any one of (1) to (6), which exhibits reverse wavelength dispersion.

  (8) The optically anisotropic layer has the following formula (1):

Wherein Y represents a divalent group, s and t each independently represent an integer of 0 or 1, G1 and G2 each independently represent —CR ¹ R ² —, R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms, a halogen atom, or a hydrogen atom, and A1 and A2 each independently represent a divalent cyclic hydrocarbon group, a divalent heterocyclic group, or methylenephenylene. Group, oxyphenylene group and thiophenylene group, A1 and A2 may be bonded to an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom, and B1 and B2 are independently, -CRR '-, - C≡C - , - CH = CH -, - CH 2 -CH 2 -, - O -, - S -, - C (= O) -, - C (= O) —O—, —O—C (═O) —, —O—C (═O) —O—. -C (= S)-, -C (= S) -O-, -OC (= S)-, -OC (= S) -O-, -CH = N-, -N = CH -, -N = N-, -N (→ O) = N-, -N = N (→ O)-, -C (= O) -NR-, -NR-C (= O)-, -OCH _2— , —NR—, —CH ₂ O—, —SCH ₂ —, —CH ₂ S—, —CH═CH—C (═O) —O—, —O—C (═O) —CH═CH -Represents a divalent group selected from the group consisting of a single bond, R and R 'each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and X1 and X2 each independently represent: Formula (2)

(Wherein A3 represents a divalent cyclic hydrocarbon group or a heterocyclic group, B3 represents the same meaning as B1 and B2, and n represents an integer of 1 to 4)
E1 and E2 each independently represents an alkylene group having 2 to 25 carbon atoms, and E1 and E2 are further an alkyl group having 1 to 5 carbon atoms, and 1 to C1 carbon atoms. 5 may be bonded to a halogen atom, P1 and P2 represent a hydrogen atom or a polymerizable group, and at least one of P1 and P2 is a polymerizable group. )
(7) The polymer containing the structural unit derived from the polymeric compound represented by (7) characterized by the above-mentioned.

  (9) The optically anisotropic layer has a first surface in contact with the vertical alignment film and a second surface parallel to the first surface, and is positioned in the vicinity of the first surface. The film according to any one of (1) to (8), wherein the rod-like polymerizable liquid crystal compound is horizontally aligned, and the rod-like polymerizable liquid crystal compound positioned in the vicinity of the second surface is vertically aligned. .

  (10) A film comprising an optically anisotropic layer containing a polymer containing a structural unit derived from a rod-like polymerizable liquid crystal compound, wherein the optically anisotropic layer has a rod-like polymerizable liquid crystal on a vertical alignment film. After forming a coating film by applying a composition containing a compound, heating the coating film at 25 ° C. to 120 ° C. for 10 seconds to 60 minutes, and further crosslinking the rod-like liquid crystal compound by photopolymerization An optically anisotropic layer obtained by peeling off the alignment film for vertical alignment, and the rod-like polymerizable liquid crystal compound is aligned horizontally on the horizontal alignment film as a monomer and vertically aligned at the air interface And satisfying nz> nx and nz> ny, where nx, ny, and nz are the refractive indices in the direction perpendicular to the film plane and in the film thickness direction, respectively. Film.

  (11) A method for producing a film having an optically anisotropic layer formed on an alignment film for vertical alignment, wherein (A) a composition containing a rod-like polymerizable liquid crystal compound on the alignment film for vertical alignment The rod-like polymerizable liquid crystal compound includes at least a step of applying, and (B) a step of heating the coating film formed in the step (A) at 25 ° C. to 120 ° C. for 10 seconds to 60 minutes. A method for producing a film, characterized by having a property of being oriented horizontally on a horizontally oriented film as a monomer and vertically oriented at an air interface.

  (12) The method for producing a film as described in (11), further comprising a step of crosslinking the rod-like liquid crystal compound by photopolymerization.

  (13) A polarizing film obtained by laminating the film according to any one of (1) to (10).

  (14) A flat panel display comprising the film according to any one of (1) to (10) or the polarizing film according to (13).

  In the film according to the present invention, an optically anisotropic layer is formed on the alignment film for vertical alignment. The optically anisotropic layer is a layer containing a rod-like polymerizable liquid crystal compound that is horizontally aligned on the horizontal alignment film and vertically aligned at the air interface. Therefore, it is possible to reduce the refractive index change in the plane direction of the film and to increase the refractive index change in the normal direction of the film.

  An embodiment of the present invention will be described as follows, but the present invention is not limited to this.

<I. Film according to the present invention>
The film according to the present invention is a film having an optically anisotropic layer formed on an alignment film for vertical alignment. The alignment film for vertical alignment is formed on the support substrate. That is, the film according to the present invention is a film in which an alignment film for vertical alignment and an optically anisotropic layer are sequentially laminated on the support substrate. That is, the film according to the present invention includes a support substrate, an alignment film for vertical alignment, and an optically anisotropic layer, and a film in which the support substrate is peeled from the film (in other words, alignment for vertical alignment). And a film in which the supporting substrate and the alignment film for vertical alignment are peeled from the film (in other words, a film made of an optically anisotropic layer) are included. In the film according to the present invention, the surface facing the optically anisotropic layer is an air layer.

  In the present specification, the “alignment film for vertical alignment” includes an alignment film for vertically aligning liquid crystal molecules (hereinafter also referred to as “vertical alignment film”) and a rubbed vertical alignment film. Meaning.

  The optically anisotropic layer is composed of a layer containing a polymer obtained by polymerizing a rod-like polymerizable liquid crystal compound. As the rod-like polymerizable liquid crystal compound, as shown in FIG. 1 (left), a rod-like polymerizable liquid crystal compound having a property of being oriented horizontally on a horizontal alignment film and vertically oriented at an air interface (in the figure, an ellipse). Is used. When such a rod-like polymerizable liquid crystal compound is used, when it is aligned on a vertical alignment film (orientation film for vertical alignment) that has not been rubbed, as shown in FIG. , Nematic vertical alignment. When the rod-like polymerizable liquid crystal compound is aligned on a rubbing-treated vertical alignment film (vertical alignment film), as shown in FIG. 1 (right), the rod-like polymerizable liquid crystal compound has an air layer interface. Then, while maintaining the molecular orientation in the vertical direction, the alignment is inclined at the interface of the film for vertical alignment. For convenience, in FIG. 1, the alignment film for vertical alignment is described as “alignment layer”, the rod-like polymerizable liquid crystal compound as “liquid crystal molecule”, and the optically anisotropic layer as “liquid crystal layer”.

  Such a film according to the present invention satisfies nz> nx and nz> ny when the refractive indexes in the orthogonal axis direction and the film thickness direction of the film plane are nx, ny, and nz, respectively. It is a film. That is, the film has a small refractive index change in the plane direction of the film and a large refractive index change in the normal direction of the film. Therefore, the film according to the present invention has an effect that the refractive index change is small in the plane direction of the film and the refractive index change is large in the normal direction of the film. Therefore, the film concerning this invention can be used as an optical film suitable for liquid crystal panels, such as IPS mode. Nz, nx, and ny are the first refractive index (nz) in the first direction perpendicular to the film, the second refractive index (nx) in the second direction perpendicular to the first direction of the film, and the film, respectively. It can also be referred to as a third refractive index (ny) in a third direction perpendicular to the first direction and the second direction.

  As an embodiment of the film according to the present invention, before curing, by controlling the orientation of a monomer or oligomer (specifically, a rod-like polymerizable liquid crystal compound) for forming a liquid crystal, The orientation of the liquid crystal layer is controlled. In this embodiment, the orientation of the monomer before curing and the orientation of the polymer after curing, ie, the liquid crystal, are considered to be the same.

  The film according to the present invention has optical anisotropy. Examples of the optical anisotropy include a tilt angle and a phase difference value. The optical anisotropy of the film according to the present invention will be described in detail with reference to FIG.

  As shown in FIG. 2, in the refractive index ellipsoid 22 showing the optical characteristics of the film 1, three-dimensional main refractive indexes na, nb, and nc are defined. The angle formed between the Y axis and the main refractive index nb is defined as a tilt angle 23, and the major axis ny and minor axis nx of the vertical ellipsoid 24 formed on the film when observed from the Z direction are defined, and the difference between ny and nx And the film thickness d (ny−nx) · d is defined as a phase difference value.

  Examples of the method for measuring the phase difference value include a method such as ellipsometer measurement. As a method for measuring the tilt angle, for example, in measuring the phase difference value, the incident angle dependency of light is measured, and curve fitting is performed using the calculated value of the change in the phase difference value of the ideal refractive index ellipsoid depending on the incident angle. The method of calculating from is mentioned.

  Usually, the retardation value is about 5 to 700 nm, and preferably about 50 to 400 nm.

  Here, the support substrate, the alignment film for vertical alignment, and the optically anisotropic layer constituting the film according to the present invention will be described in more detail below.

(I-1) Support base material The support base material is not particularly limited as long as it can form an alignment film for vertical alignment on the support base material. For example, glass, a plastic sheet, a plastic film, and a translucent film can be mentioned. Examples of the translucent film include polyolefin films such as polyethylene, polypropylene, and norbornene polymers, polyvinyl alcohol films, polyethylene terephthalate films, polymethacrylic acid ester films, polyacrylic acid ester films, cellulose ester films, polyethylene naphthalates. Examples thereof include a phthalate film, a polycarbonate film, a polysulfone film, a polyethersulfone film, a polyetherketone film, a polyphenylene sulfide film, and a polyphenylene oxide film.

  In general, an optically anisotropic layer using a polymerizable liquid crystal compound is a thin film, and needs strength of the film, for example, a bonding process using the film of the present invention, a process of transporting and storing the film, and the like. Even in the process, by using a supporting substrate, it can be easily handled without tearing.

(I-2) Alignment film for vertical alignment In the film of the present invention, the alignment film for vertical alignment has solvent resistance that does not dissolve due to coating of an optically anisotropic layer, removal of solvent, and heating of liquid crystal alignment. It is necessary to have heat resistance by treatment, and to prevent peeling due to friction by rubbing, etc., and it is a polymer or a composition containing a polymer.

  The polymer is not particularly limited as long as it is formed on the support substrate. For example, polyamides and gelatins having an amide bond in the molecule, polyimides having an imide bond in the molecule and hydrolyzed products thereof such as polyamic acid, polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polyacrylic acid, polyacrylic Examples thereof include polymers such as acid esters. These polymers may be used alone, or two or more of them may be mixed or copolymerized. These polymers can be easily obtained by polycondensation such as dehydration and deamination, chain polymerization such as radical polymerization, anion polymerization, and cation polymerization, coordination polymerization, and ring-opening polymerization.

  In addition, such a polymer can introduce organic groups such as alicyclic groups such as steroids, long-chain alkyl groups, fluorinated alkyl groups, aromatic ring structures, and fluorine-containing aromatic ring structures. By introducing the structure as described above, the rod-like polymerizable liquid crystal compound can be more easily vertically aligned. Also, compounds containing organic groups such as alicyclic groups such as steroids, long-chain alkyl groups, fluorinated alkyl groups, aromatic ring structures and fluorine-containing aromatic ring structures, onium salts, cesium ions, rubidium ions, etc. The rod-like polymerizable liquid crystal compound can be more easily vertically aligned by using a composition to which an inorganic salt or organic acid salt is added.

  Specific examples of the polymer include, for example, polyimides disclosed in JP-A No. 2001-305549, WO 2003-042752, JP-A No. 2005-139228, Liquid Crystal Vol. 8, No. 4, page 216 and the like, and polyamic acids thereof. Examples thereof include polyvinyl alcohol disclosed in JP-A Nos. 2005-196015, 2005-315988, and 2005-196016. Further, a polyimide alignment film for vertical alignment (trade name SE-5300, manufactured by Nissan Chemical Co., Ltd.) used in Examples described later is also a polyimide alignment film for vertical alignment.

  The thickness of the alignment film for vertical alignment is not particularly limited, but is preferably 10 nm to 10000 nm, and more preferably 10 nm to 1000 nm. If it is in the said range, the film obtained can be reduced in weight. Moreover, the influence which the optical characteristic which the alignment film for vertical alignment has on the film obtained can be made small.

  The alignment film for vertical alignment may be rubbed as necessary. When a rod-like polymerizable liquid crystal compound described later is aligned in a liquid crystal state on an alignment film for vertical alignment that has not been rubbed, the rod-shaped polymerizable liquid crystal compound is nematically aligned vertically with respect to the alignment film for vertical alignment. . Therefore, the film obtained is a vertically oriented film.

  On the other hand, when the rod-like polymerizable liquid crystal compound described later is aligned in a liquid crystal state on the rubbing-treated vertical alignment film, the rod-like polymerizable liquid crystal compound remains vertically aligned at the air layer interface. At the alignment film interface for vertical alignment, tilt alignment is performed. Therefore, the obtained film becomes a tilted orientation film.

  That is, the film of the present invention includes both a vertically oriented film and a tilted oriented film.

(I-3) Optically anisotropic layer The optically anisotropic layer is a layer having optical anisotropy formed on the alignment film for vertical alignment. The optically anisotropic layer is composed of a layer containing a polymer containing a structural unit derived from a rod-like polymerizable liquid crystal compound. The optically anisotropic layer may contain a polymer containing a structural unit derived from a compound other than the rod-like polymerizable liquid crystal compound. For example, in order to impart desired wavelength dispersion characteristics to the film according to the present invention, a polymer containing a structural unit derived from a specific polymerizable compound may be used in addition to a structural unit derived from a rod-like polymerizable liquid crystal compound. . Further, a rod-like polymerizable liquid crystal compound and a liquid crystal compound different from the specific polymerizable compound (hereinafter, may be referred to as “other liquid crystal compounds” for convenience of explanation) may be included. Furthermore, a polymerization initiator, a polymerization inhibitor, a photosensitizer, a leveling agent and the like may be contained. In addition, the detail of the compound which comprises an optically anisotropic layer is mentioned later.

  What is necessary is just to adjust the thickness of the said optically anisotropic layer suitably so that the phase difference value (retardation value, Re ((lambda))) of the film obtained may become a desired value. Re (λ) is determined by the following mathematical formula (a). That is, in order to obtain a desired Re (λ), the film thickness d may be adjusted.

Re (λ) = d × Δn (λ) (a)
(In the formula, Re (λ) represents a retardation value at a wavelength λnm, d represents a film thickness, and Δn (λ) represents a refractive index anisotropy at a wavelength λnm.)
In a preferred embodiment of the film according to the present invention, the alignment film for vertical alignment is a vertical alignment film, and the refractive index ellipsoid of the rod-like polymerizable liquid crystal compound is 90 ± 5 ° with respect to the film plane. It is preferable to have an inclination angle of Thereby, the said film turns into a vertical alignment film.

  In another embodiment, the alignment film for vertical alignment is a rubbing-processed vertical alignment film, and the refractive index ellipsoid of the rod-like polymerizable liquid crystal compound is in the plane of the film at the alignment film interface for vertical alignment. On the other hand, it preferably has an inclination angle of 45 ° to 85 °. Thereby, the said film turns into an inclination orientation film.

  Hereinafter, the rod-like polymerizable liquid crystal compound, other liquid crystal compound, polymerizable compound, and other constituent compounds that can be contained in the optically anisotropic layer will be described in detail.

(I-3-1) Rod-like polymerizable liquid crystal compound The rod-like polymerizable liquid crystal compound contained in the optically anisotropic layer is rod-like polymerizable that is aligned horizontally on a horizontal alignment film as a monomer and vertically aligned at an air interface. It is a liquid crystal compound. The above-mentioned “rod-like polymerizable liquid crystal compound that is aligned horizontally on a horizontal alignment film as a monomer and vertically aligned at an air interface” means, for example, polyvinyl alcohol as a horizontal alignment film on a glass substrate whose surface is processed horizontally The rod-like polymerizable liquid crystal compound in which the orientation obtained when a rod-like polymerizable liquid crystal compound is applied as a monomer on a substrate provided with an orientation film that induces horizontal orientation is horizontal on the orientation film and vertically oriented at the air interface It is. The rod-like polymerizable liquid crystal compound maintains such orientation even when polymerized, and gives a high refractive index in the normal direction of the film.

  Such a so-called polymerizable liquid crystal compound imparting hybrid alignment is a liquid crystal containing a structural unit derived from a single or two or more kinds of rod-like polymerizable liquid crystal compounds, such as JP-A No. 2005-320317 and JP-A No. 2005-320317. The polymerizable liquid crystal compound shown by 2001-55573 is mentioned. Further, the orientation may be controlled by adding a silicon-based oligomer compound, a fluorine-containing polymer, a (meth) acrylic monomer, a nonionic surfactant, or the like to the rod-like polymerizable liquid crystal compound. Examples of such a method include methods disclosed in JP-A-9-288210, JP-A-2006-16599, and JP-A-2005-196221.

  Specific examples of the above rod-like polymerizable liquid crystal compounds include the liquid crystal manual (edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd., October 30, 2000), chapter 3 of molecular structure and liquid crystal, 3.2 non-chiral rod-like shape. Among the compounds described in Liquid crystal molecules, 3.3 Chiral rod-like liquid crystal molecules, compounds having a polymerizable group may be mentioned.

  More specifically, a rod-like polymerizable liquid crystal compound contained in RMS-03-011 (trade name, manufactured by Merck & Co., Inc.) used in Examples described later can be given.

  In the film according to the present invention, a rod-like polymerizable liquid crystal compound having a hybrid orientation as described above is used as the rod-like polymerizable liquid crystal compound instead of the conventionally used homeotropic-orientated rod-like polymerizable liquid crystal compound. The inclination angle of the refractive index ellipsoid in the optically anisotropic layer obtained by polymerizing the compound can be arbitrarily controlled in the normal direction. More specifically, when the rod-like polymerizable liquid crystal compound is aligned in a liquid crystal state on the vertical alignment film that is not rubbed among the alignment films for vertical alignment, the rod-like polymerizable liquid crystal compound is vertically aligned. After the nematic vertical alignment with respect to the alignment film for use, the film is polymerized while maintaining the alignment. On the other hand, when the rod-like polymerizable liquid crystal compound is aligned in a liquid crystal state on the rubbed vertical alignment film, the rod-like polymerizable liquid crystal compound remains vertically aligned at the air layer interface. At the alignment film interface, after the tilt alignment, the film is polymerized while maintaining the orientation.

  Therefore, the film according to the present invention has a small refractive index change in the plane direction of the film and a large refractive index change in the normal direction of the film.

  The rod-like polymerizable liquid crystal compound may be polymerized by any polymerization mode. For example, a thermally polymerizable rod-like polymerizable liquid crystal compound and a photopolymerizable rod-like polymerizable liquid crystal compound can be exemplified. In the present invention, a photopolymerizable rod-like polymerizable liquid crystal compound is particularly preferable. According to this, the rod-like polymerizable liquid crystal compound can be polymerized and fixed at a low temperature. Therefore, the range of selection of the support substrate is widened, and at the same time, it is industrially advantageous.

(I-3-2) Other liquid crystal compound The polymer containing the structural unit derived from the rod-shaped polymerizable liquid crystal compound contained in the optically anisotropic layer has a structural unit derived from a different kind of liquid crystal compound. It may be included.

  The liquid crystal compound is preferably, for example, a compound represented by the following formula (3), formula (4), formula (5), formula (6), formula (7), or formula (8).

P11-E11-B11-A11-B12-A12-B14-A14-B15-E12-P12 (3)
P11-E11-B11-A11-B12-A12-B14-A14-B13-F11 (4)
P11-B11-A11-B12-A12-B14-A14-B13-F11 (5)
P11-E11-B11-A11-B12-A12-F11 (6)
P11-B11-A11-B12-A12-B13-F11 (7)
P11-E11-B11-A11-B12-A12-B13-F11 (8)
In the above formula (3), formula (4), formula (5), formula (6), formula (7) and formula (8), A11, A12 and A14 are each independently a divalent cyclic ring. A hydrocarbon group, a divalent heterocyclic group, a methylenephenylene group, an oxyphenylene group, or a thiophenylene group is represented. A11, A12, and A14 may be bonded to an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom.

B11, B12, B13, B14, and B15 are each independently, -CRR '-, - C≡C - , - CH = CH -, - CH 2 -CH 2 -, - O -, - S -, - C (═O) —, —C (═O) —O—, —O—C (═O) —, —O—C (═O) —O—, —C (═S) —, —C ( = S) -O-, -OC (= S)-, -OC (= S) -O-, -CH = N-, -N = CH-, -N = N-, -N ( → O) = N—, —N═N (→ O) —, —C (═O) —NR—, —NR—C (═O) —, —OCH ₂ —, —NR—, —CH ₂ O —, —SCH ₂ —, —CH ₂ S—, —CH═CH—C (═O) —O—, —O—C (═O) —CH═CH—, and a group consisting of a single bond ( R and R ′ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. It represents a more divalent group selected.

  E11 and E12 each independently represents an alkylene group having 2 to 25 carbon atoms. Further, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom may be bonded to E11 and E12.

  P11 in the formulas (4) to (8) represents a polymerizable group. P11 and P12 in the formula (3) represent a hydrogen atom or a polymerizable group, and at least one of P11 and P12 is a polymerizable group.

  F11 represents a halogen atom such as a hydrogen atom, an alkyl group, a nitrile group, a nitro group, a trifluoromethyl group, or a fluorine atom, or a hydrogen atom.

  Other liquid crystal compounds include, among others, the following formulas (3-1) to (3-6), formula (6-1), formula (6-2), formula (8-1), and formula (8- 2)

Or a liquid crystal compound represented by any one of the following formulas (3-7) to (3-12), (4-1) to (4-4), formula (5-1), and formula (5-2): , Formula (7-1), and Formula (7-2)

A liquid crystal compound represented by any one of the above is preferable because it is easily available.

(I-3-3) Polymerizable compound The polymer of the optically anisotropic layer further includes a structural unit derived from a specific polymerizable liquid crystal compound in order to impart desired wavelength dispersion characteristics of the obtained film. A polymer may be used.

  The “specific polymerizable compound” is a compound that can impart desired wavelength dispersion characteristics to the resulting film by being used in combination with the rod-like polymerizable liquid crystal compound.

  As such a polymerizable compound, the following formula (1)

(In the formula, Y represents a divalent group, s and t each independently represent an integer of 0 or 1, and G1 and G2 each independently represent —CR ¹ R ² — (where R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms, a halogen atom, or a hydrogen atom, and A1 and A2 each independently represent a divalent cyclic hydrocarbon group or a divalent heterocyclic ring. Group, a methylenephenylene group, an oxyphenylene group, or a thiophenylene group, and A1 and A2 may be bonded to an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom. well, B1 and B2 are each independently, -CRR '-, - C≡C - , - CH = CH -, - CH 2 -CH 2 -, - O -, - S -, - C (= O) -, -C (= O) -O-, -O-C (= O) , -O-C (= O) -O-, -C (= S)-, -C (= S) -O-, -O-C (= S)-, -O-C (= S)- O-, -CH = N-, -N = CH-, -N = N-, -N (→ O) = N-, -N = N (→ O)-, -C (= O) -NR- , —NR—C (═O) —, —OCH ₂ —, —NR—, —CH ₂ O—, —SCH ₂ —, —CH ₂ S—, —CH═CH—C (═O) —O—. , —O—C (═O) —CH═CH—, and a group consisting of a single bond (wherein R and R ′ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). Represents a divalent group, and X1 and X2 each independently represent the following formula (2)

(Wherein, A3 represents a divalent cyclic hydrocarbon group or a heterocyclic group,, B3 is, -CRR '-, - C≡C - , - CH = CH -, - CH 2 -CH 2 -, - O—, —S—, —C (═O) —, —C (═O) —O—, —O—C (═O) —, —O—C (═O) —O—, —C ( = S)-, -C (= S) -O-, -OC (= S)-, -O-C (= S) -O-, -CH = N-, -N = CH-,- N = N -, - N ( → O) = N -, - N = N (→ O) -, - C (= O) -NR -, - NR-C (= O) -, - OCH 2 -, —NR—, —CH ₂ O—, —SCH ₂ —, —CH ₂ S—, —CH═CH—C (═O) —O—, —O—C (═O) —CH═CH—, and Group consisting of a single bond (R and R ′ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) ) Is selected from a divalent radical, n is an integer of 1 to 4)
E1 and E2 each independently represents an alkylene group having 2 to 25 carbon atoms, and E1 and E2 each represents an alkyl group having 1 to 5 carbon atoms and a carbon number An alkoxy group of 1 to 5 or a halogen atom may be bonded, P1 and P2 represent a hydrogen atom or a polymerizable group, and at least one of P1 and P2 is a polymerizable group. )
It is a compound represented by these.

  Y in the above formula (1) represents a divalent group, and this group preferably has a bent structure. Here, the “bending structure” is an angle formed from a bonding group that is a bonding group of Y and bonded to a group containing A1, and a bonding group that is a bonding group of Y and bonded to a group containing A2. Means a structure of 100 ° to 140 °. The angle is preferably 110 ° to 130 °. If it is the said range, compatibility will be improved when a polymerizable compound and a rod-like polymerizable liquid crystal compound are dissolved in an organic solvent. Therefore, the retardation value of the obtained film can be improved.

  As specific Y, following formula (9)

The bivalent group etc. which are represented by these can be illustrated.

  An angle formed by a linking group that is bonded to Y and is a group that includes A1 and a linking group that is Y and is bonded to a group that includes A2 is defined as A1, A2, C1, D1, In terms of D2, (G1) s, and (G2) t, when s = t = 1 in the above formula (1), the angle can be represented by a double arrow in the following formula (9-1). Similarly, when s = t = 0 in the above formula (1), the angle can be expressed by the following formula (9-2).

  In the above formula (9), C1 represents a quaternary carbon atom or a quaternary silicon atom. Of these, C1 is preferably a quaternary carbon atom because of easy production.

  In the above formula (9), each of D1 and D2 represents a cyclic hydrocarbon group, a heterocyclic group, a linear hydrocarbon group having 1 to 5 carbon atoms, or a branched hydrocarbon group having 1 to 5 carbon atoms. To express. Examples of the cyclic hydrocarbon group used for D1 and D2 include a cycloalkyl group having about 5 to 12 carbon atoms such as a cyclopentyl group and a cyclohexyl group;

Or an aromatic group having about 6 to 18 carbon atoms represented by any of the above.

  In addition, examples of the heterocyclic group used for D1 and D2 include the following formulas such as a 5-membered ring and a 6-membered ring.

Or a group represented by any of the above.

  D1 and D2 may be linked by a hydrocarbon group having 1 to 5 carbon atoms, an amino group, an ether group, a thioether group, or a single bond. D1 and D2 include a hydroxyl group, an amino group, a thiol group, a cyclic hydrocarbon group, a linear or branched alkyl group having 1 to 5 carbon atoms, and a linear or branched structure having 1 to 5 carbon atoms. An alkoxy group, a trifluoromethyl group, a trifluoromethyloxy group, a nitrile group, a nitro group, or a halogen atom may be bonded.

  Here, examples of the hydrocarbon group include alkylene groups such as a methylene group, an ethylene group, and a propylene group, and a linking group in which a single bond of the alkylene group is substituted with a double bond or a triple bond. Examples of the cyclic hydrocarbon group include the same cyclic hydrocarbon groups as those used for D1 and D2. As the alkyl group, alkoxy group and halogen atom, the alkyl group, alkoxy group and halogen atom exemplified as the group substituted by A1 and A2 can be exemplified similarly.

  Specific examples of the group represented by the above formula (9) include the following formulas (D-1) to (D-18).

(In this case, a carbon atom is illustrated as a quaternary atom C1 because of easy production), C1 is a carbon atom, and both D1 and D2 are phenyl groups. Some substituents can be mentioned.

  Note that some of the hydrogen atoms contained in the exemplified structure are alkyl groups having about 1 to 4 carbon atoms such as a methyl group, an ethyl group, an i-propyl group, and a t-butyl group; a methoxy group, an ethoxy group, and the like A trifluoromethyl group; a trifluoromethyloxy group; a nitrile group; a nitro group; and a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom.

  Y is a substituent in which C1 is a carbon atom and D1 and D2 are both phenyl groups, or from the above formulas (D-1) to (D-12), from the viewpoint of ease of production. A substituent is preferred. In particular, the substituents represented by the above formulas (D-1) to (D-12) are preferable from the viewpoint of remarkably showing reverse wavelength dispersion.

  In (G1) s and (G2) t in the above formula (1), s and t each independently represents an integer of 0 or 1.

If s and t is 1, G1 and G2, independently, ^-CR 1 ^{R 2} - is. Here, R ¹ and R ² each independently represents an alkyl group having about 1 to 4 carbon atoms such as a methyl group or an ethyl group; and a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom.

  When s and t are 0, Y and A1 are single-bonded, and Y and A2 are single-bonded.

  In the above formula (1), A1 and A2 each independently represent a divalent cyclic hydrocarbon group, a divalent heterocyclic group, a methylenephenylene group, an oxyphenylene group, or a thiophenylene group. Here, the methylene group, ether group, and thioether group in the methylenephenylene group, oxyphenylene group, or thiophenylene group are bonded to B1 and B2.

  Examples of the divalent cyclic hydrocarbon group used for A1 and A2 include the following formulas:

An aromatic group having about 6 to 18 carbon atoms represented by any one of the following formulae:

An alicyclic group consisting of a 5-membered ring and a 6-membered ring represented by the formula:

And heterocyclic groups composed of a 5-membered ring and a 6-membered ring represented by any of the above.

  In addition, as A1 and A2, a part of hydrogen atoms of the exemplified groups are alkyl groups having about 1 to 4 carbon atoms such as methyl group, ethyl group, i-propyl group, t-butyl group; methoxy group, An alkoxy group having about 1 to 4 carbon atoms such as an ethoxy group; a trifluoromethyl group; a trifluoromethyloxy group; a nitrile group; a nitro group; may be substituted with a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom .

  From the viewpoint of ease of production, both A1 and A2 are preferably the same type of group. In particular, A1 and A2 are preferably a 1,4-phenylene group, a 1,4-cyclohexylene group, or a divalent group in which 1 to 3 carbon atoms of the benzene ring are substituted with nitrogen atoms. More preferred is a 4-phenylene group.

B1 and B2 are each independently, -CRR '-, - C≡C - , - CH = CH -, - CH 2 -CH 2 -, - O -, - S -, - C (= O) -, -C (= O) -O-, -OC (= O)-, -OC (= O) -O-, -C (= S)-, -C (= S) -O-, -OC (= S)-, -OC (= S) -O-, -CH = N-, -N = CH-, -N = N-, -N (→ O) = N-, -N = N (→ O) - , - C (= O) -NR -, - NR-C (= O) -, - OCH 2 -, - NR -, - CH 2 O -, - SCH 2 -, —CH ₂ S—, —CH═CH—C (═O) —O—, —O—C (═O) —CH═CH—, represents a divalent group selected from the group consisting of a single bond. Here, R and R ′ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms such as a methyl group or an ethyl group, or a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom.

  From the viewpoint of ease of production, both B1 and B2 are preferably the same type of divalent group.

  In the above formula (1), when s and t are 0, B1 and B2 are preferably —CRR′—, —O—, —S— or NR—.

  When B1 and B2 are the above linking groups, the connecting portion between A1 (A2) and B1 (B2) and the connecting portion between B1 (B2) and X1 (X2) are bent, and the connecting group Y This is preferable because the compatibility with the rod-like polymerizable liquid crystal compound to be mixed tends to be improved.

  In the above formula (1), when s and t are 1, and preferably G1 and G2 are methylene groups, B1 and B2 are a single bond, —C≡C—, —O—. C (═O) —O—, —O—C (═O) —, or —O—C (═O) —O— is preferable.

  When B1 and B2 are the above-mentioned linking groups, the production is easy, and X2-B2-A2 and A1-B1-X1 in the above formula (1) are linear, and thus tend to improve the orientation. This is preferable.

  X1 and X2 in the above formula (1) are the following formula (2)

The bivalent group represented by these is represented.

  In the above formula (2), A3 represents a divalent cyclic hydrocarbon group or a divalent heterocyclic group. Specifically, as A3, the divalent cyclic hydrocarbon group and the divalent heterocyclic group exemplified in A1 and A2 can be exemplified similarly. From the viewpoint of ease of production, a 1,4-phenylene group, 1,4-cyclohexylene group, or a divalent group in which 1 to 3 carbon atoms of the benzene ring are substituted with nitrogen atoms is preferable. More preferably, it is a 1,4-phenylene group.

  Further, from the viewpoint of ease of production, it is preferable that both X1 and X2 are the same type of divalent group.

  B3 can be defined in the same way as B1. Among these, from the viewpoint of ease of production, —OC (═O) —, —C (═O) —O—, —O—, or a single bond is preferable.

  n represents an integer of 1 to 4. When n is 2 or more, as in the compounds (1-2) to (1-4) in Table 1 described later, the structural units composed of A3 and B3 may be different from each other.

  When casting the composition containing the obtained polymerizable compound, n is preferably 1 or 2 from the viewpoint of easy handling. Furthermore, n is preferably 1 from the viewpoint of ease of production.

  E1 and E2 each independently represent an alkylene group having 2 to 25 carbon atoms, preferably an alkylene group having 4 to 10 carbon atoms.

  The hydrogen atom of E1 and E2 may be substituted by an alkyl group, an alkoxy group, a trifluoromethyl group, a trifluoromethyloxy group, a nitrile group, a nitro group, or a halogen atom, but remains a hydrogen atom Is preferred.

  It is preferable that both E1 and E2 are the same type of alkylene group because production is easy.

  P1 and P2 represent a hydrogen atom or a polymerizable group.

  In the present specification, the “polymerizable group” means a substituent capable of polymerizing the polymerizable compound and the rod-shaped polymerizable liquid crystal compound described above. Specifically, a vinyl group, a p-stilbene group, an acryloyl group, a methacryloyl group, a carboxyl group, a methylcarbonyl group, a hydroxyl group, an amide group, an alkylamino group, an amino group, an epoxy group, an oxetanyl group, Examples include aldehyde groups, isocyanate groups, and thioisocyanate groups.

  In addition, the polymerizable group may include a group exemplified by B1 or B2 in order to link the above exemplified group and E1 or E2.

  Among them, an acryloyl group or a methacryloyl group is preferable, and an acryloyl group is more preferable. If these groups are used, the handling during photopolymerization is easy and the production is also easy.

  It is preferable that at least one of P1 and P2 is a polymerizable group, and it is more preferable that both P1 and P2 are a polymerizable group. Thereby, the film | membrane hardness of the film obtained can be made favorable.

  Specific examples of the polymerizable compound include compounds represented by Tables 1 to 4.

  The optically anisotropic layer may contain any of structural units derived from the polymerizable compound, but may contain structural units derived from a plurality of different polymerizable compounds. . Especially, it is preferable that the structural unit derived from the compound of Table 1 and 2 is contained. If such a compound is used, the film concerning this invention can show reverse wavelength dispersion notably. Furthermore, it is more preferable that the structural unit derived from the compound of Table 1 is included. If such a compound is used, the film concerning this invention can be manufactured easily.

  Here, the notation of the table will be described using the compound (1-1) as an example. “A1 = A2” represents that A1 and A2 are the same phenylene group. “B1 = A side of B2” represents that the ether part of the ester group is bonded to A (phenylene group). “B1 = B2 on X side” means that the carbonyl portion of the ester group is bonded to X (phenylene ether group). Further, when there is no designation of the side, it indicates that the direction may be replaced in any direction.

  As a polymeric compound, the compound of Table 1 or Table 2 is preferable, the compound of Table 1 is more preferable, and following formula (1-1), (1-2), (1-3), (1 -4), (1-5), (1-11), (1-45), (1-49), and compounds represented by (1-50) are particularly preferable.

  As a method for producing a polymerizable compound in which s = t = 0 in the above formula (1) like the compound represented by the above formula (1-1), for example, structures of C1, D1, and D2 are given. The corresponding carbonyl compound is used as a compound, and dehydration condensation is performed on the carbonyl compound by reacting a halide of a compound containing A1 (A2), B1 (B2), X1 (X2), E1 (E2) and P1 (P2). Can be mentioned. Compounds including A1 (A2), B1 (B2), X1 (X2), E1 (E2) and P1 (P2) are A1 (= A2), B1 (= B2), X1 (= X2), E1 (= E2), a compound containing each structural unit of P1 (= P2) is subjected to dehydration condensation reaction, esterification reaction, Williamson reaction, Ullmann reaction, benzylation reaction, Sonogashira reaction, Suzuki-Miyaura reaction, Negishi reaction, Kumada reaction, It can be produced by bonding by the Hiyama reaction, the Buchwald-Hartwig reaction, the Wittig reaction, the Friedel-Craft reaction, the Heck reaction, or the aldol reaction.

  As a compound represented by the above formula (1-2), as a method for producing a polymerizable compound in which s and t in the above formula (1) are 1 and G1 and G2 are both methylene chains, For example, a benzyl halide having iodine on a benzene ring as a compound giving a structural unit of C2 and A1 (C3 and A2) to the carbonyl compound is reacted with an alkali metal hydroxide to give A1 (A2), C1, A method comprising synthesizing a compound containing G1 (G2), D1 and D2 and reacting with a compound containing B1 (B2), X1 (X2), E1 (E2) and P1 (P2), which are separately synthesized, is obtained in the same manner. The compounds giving the structures of B1 (B2), X1 (X2), E1 (E2), and P1 (P2) are sequentially repeated from the compounds containing A1, A2, C1, G1, G2, D1 and D2. It can be mentioned, such as how to.

  The wavelength dispersion characteristic of the obtained film is determined by the ratio of the rod-like polymerizable liquid crystal compound and the structural unit derived from the polymerizable compound. In this invention, when not containing the said polymeric compound, the film obtained becomes a film which shows positive wavelength dispersion. On the other hand, by increasing the content of the structural unit derived from the polymerizable compound, the wavelength dispersion characteristic can be arbitrarily adjusted from the normal wavelength dispersion to the reverse wavelength dispersion. Therefore, the film according to the present invention preferably contains the polymerizable compound in an amount capable of obtaining desired wavelength dispersion characteristics. The content of the polymerizable compound necessary for imparting desired wavelength dispersion characteristics can be determined as follows. For example, the ratio of the structural unit derived from the polymerizable compound contained in the composition containing the rod-like polymerizable liquid crystal compound and the polymerizable compound is adjusted, and the retardation value of the obtained film is obtained. From the result, the content of the structural unit derived from the polymerizable compound can be determined.

(I-3-4) Other constituent compounds [polymerization initiator]
The optically anisotropic layer may contain a polymerization initiator for polymerizing the rod-like polymerizable liquid crystal compound or the polymerizable compound. The polymerization initiator is not particularly limited as long as it can be used to polymerize the compound. As a preferred embodiment of the film according to the present invention, the rod-like polymerizable liquid crystal compound is preferably photopolymerized. Therefore, the polymerization initiator is preferably a photopolymerization initiator.

  Examples of the photopolymerization initiator include benzoins, benzophenones, benzyl ketals, α-hydroxy ketones, α-amino ketones, iodonium salts, sulfonium salts, and more specifically, Irgacure (Irgacure). 907, Irgacure 184, Irgacure 651, Irgacure 250, and Irgacure 369 (all manufactured by Ciba Specialty Chemicals), Seiko All BZ, Seiko All Z, Seiko All BEE (all manufactured by Seiko Chemical Co., Ltd.), kayacure BP100 ( Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (Dow), Adeka optomer SP-152, Adeka optomer SP-170 (all asahi Denka) and the like.

  By using such a photopolymerization initiator, the rod-like polymerizable liquid crystal compound and the polymerizable compound can be photopolymerized. In addition, the content of such a polymerization initiator is preferably 10% by weight or less with respect to the liquid crystal compound-containing composition described later so that the orientation of the rod-like polymerizable liquid crystal compound is not disturbed.

(Polymerization inhibitor)
The optically anisotropic layer may contain a polymerization inhibitor. The polymerization inhibitor is not particularly limited. For example, hydroquinones having a substituent such as hydroquinone and alkyl ether, catechols having a substituent such as alkyl ether such as butylcatechol, pyrogallols, 2, Mention may be made of radical scavengers such as 2,6,6, -tetramethyl-1-piperidinyloxy radical, thiophenols, β-naphthylamines, and β-naphthols.

  By using the polymerization inhibitor, the polymerization of the rod-like polymerizable liquid crystal compound or the polymerizable compound can be controlled, and the stability of the optically anisotropic layer can be improved.

[Photosensitizer]
The optically anisotropic layer may contain a photosensitizer. The photosensitizer is not particularly limited, and examples thereof include xanthones such as xanthone and thioxanthone, anthracene having a substituent such as anthracene and alkyl ether, phenothiazine, and rubrene.

  By using the photosensitizer, the polymerization of the rod-like polymerizable liquid crystal compound or polymerizable compound can be made highly sensitive.

(Leveling agent)
Further, the optically anisotropic layer may contain a leveling agent. The leveling agent is not particularly limited, and a conventionally known leveling agent can be added. Examples of the leveling agent include additives for radiation-curing coatings (BYK-352, BYK-353, BYK-361N) and coating additives (manufactured by Toray Dow Corning: SH28PA, DC11PA, ST80PA). And paint additives (manufactured by Shin-Etsu Silicone Co., Ltd .: KP321, KP323, X22-161A, KF6001) and the like.

  By using the leveling agent, the optically anisotropic layer can be smoothed. Furthermore, in the process of producing the film, the fluidity of the liquid crystal compound-containing composition described later can be controlled, and the crosslink density of the rod-like polymerizable liquid crystal compound and the polymerizable compound can be adjusted.

<II. Production Method of Film According to the Present Invention>
The manufacturing method of the film concerning this invention can be used suitably for manufacturing the film concerning this invention mentioned above. Specifically, (A) a step of applying the above-described composition containing the rod-like polymerizable liquid crystal compound on the alignment film for vertical alignment (hereinafter, also referred to as “liquid crystal compound-containing composition application step”); B) Step of heating the coating film formed in the liquid crystal compound-containing composition coating step at 25 ° C. to 120 ° C. for 10 seconds to 60 minutes (hereinafter, also referred to as “(liquid crystal compound-containing composition heating step)”) And at least.

  According to the above configuration, when a vertical alignment film is used as the vertical alignment film, the rod-like polymerizable liquid crystal compound can be nematically aligned vertically on the vertical alignment film. Furthermore, if a rubbing-processed vertical alignment film is used as the vertical alignment film, the rod-like polymerizable liquid crystal compound is vertically aligned at the air layer interface and tilted at the vertical alignment film interface. Can do. Therefore, according to the above configuration, both the unpolymerized film before polymerization and the polymerized film can produce a film having a small change in refractive index in the plane direction of the film and a large change in refractive index in the normal direction of the film. it can.

  In addition, as described above, the tilt angle of the refractive index ellipsoid in the optically anisotropic layer can be arbitrarily set in the normal direction by merely aligning the rod-shaped polymerizable liquid crystal compound with or without rubbing treatment on the alignment film for vertical alignment. Can be controlled. Therefore, a film having a desired optical anisotropy can be easily produced.

  The alignment film for vertical alignment and the rod-like polymerizable liquid crystal compound have <I. What was described in the film concerning this invention> can be used similarly. Therefore, <I. Among the alignment films for vertical alignment described in <Film according to the present invention>, in the optically anisotropic layer formed on the non-rubbed vertical alignment film, the rod-like polymerizable liquid crystal compound is the alignment film for vertical alignment. Nematic vertical alignment with respect to. On the other hand, in the optically anisotropic layer formed on the rubbed vertical alignment film, the rod-like polymerizable liquid crystal compound remains vertically aligned at the air layer interface, and is inclined at the vertical alignment film interface. To do. That is, in the optically anisotropic layer formed through the liquid crystal compound-containing composition coating step and the liquid crystal compound-containing composition heating step, the inclination angle of the refractive index ellipsoid in the optically anisotropic layer is arbitrarily set in the normal direction. Can be controlled. Therefore, it is possible to produce a film having a small change in refractive index in the plane direction of the film and a large change in refractive index in the normal direction of the film.

  In addition to the liquid crystal compound-containing composition coating step and the liquid crystal compound-containing composition heating step, the method for producing a film according to the present invention includes (C) a rod-like polymerizable liquid crystal compound to be coated on the alignment film for vertical alignment. A step of preparing a composition to be contained (hereinafter, also referred to as “liquid crystal compound-containing composition preparation step”), and a step of polymerizing an unpolymerized film obtained in (D) a heating step of the liquid crystal compound-containing composition (hereinafter referred to as “liquid crystal (Also referred to as “compound polymerization step”), (E) a step of rubbing a vertical alignment film (hereinafter also referred to as “rubbing step”), and (F) a step of forming an alignment film for vertical alignment on a supporting substrate (hereinafter referred to as “vertical”). It may also be referred to as an “alignment alignment film forming step”. All of these four steps may be included, or any one or two of them may be included. Of course, none of them may be included.

  Hereinafter, the alignment film forming process for vertical alignment, the rubbing process, the liquid crystal compound-containing composition preparation process, the liquid crystal compound-containing composition coating process, the liquid crystal compound-containing composition heating process, and the liquid crystal compound polymerization process will be described in detail.

(II-1) Vertical Alignment Film Formation Step In the vertical alignment film formation step, a vertical alignment film is formed on the support substrate. The support substrate is not particularly limited. For example, <I. The support substrate exemplified in the film according to the present invention can be used. The alignment film for vertical alignment is not particularly limited. For example, <I. The alignment film for vertical alignment exemplified in the film according to the present invention can be used. If such an alignment film for vertical alignment is used, it is not necessary to control the refractive index by stretching, so that in-plane variation in birefringence is reduced. Therefore, there is an effect that it is possible to provide a large optical film that can cope with an increase in the size of the FPD on the support substrate.

  The method of forming the alignment film for vertical alignment on the support substrate is not particularly limited, and a conventionally known method can be used. For example, the alignment film for vertical alignment can be formed on the support substrate by applying a material for the alignment film for vertical alignment on the support substrate and then annealing.

  The thickness of the alignment film for vertical alignment thus obtained is not particularly limited, but is preferably 10 nm to 10000 nm, and more preferably 10 nm to 1000 nm. If it is the said range, in the optically anisotropic layer formation process mentioned later, a rod-shaped polymerizable liquid crystal compound can be aligned at a desired angle on the said alignment film for vertical alignment.

(II-2) Rubbing process In the rubbing process, the vertical alignment film obtained in the vertical alignment film forming process is rubbed. Thereby, in the liquid crystal compound-containing composition heating step described later, the rod-like polymerizable liquid crystal compound can be tilted and aligned at the interface film for vertical alignment while maintaining the vertical alignment at the air layer interface. The alignment film for vertical alignment does not have to be obtained in the step of forming the alignment film for vertical alignment, and is an alignment film for vertical alignment having the same physical properties, for example, Commercial products may be used.

  The method for rubbing the vertical alignment film is not particularly limited, and a conventionally known method can be used. For example, a method can be used in which a rubbing roll wound with a rubbing cloth is brought into contact with a vertical alignment film that is placed on a stage and conveyed.

  The rubbing cloth is not particularly limited as long as it can be wound around a rubbing roll. Examples of the material of the rubbing cloth include various materials such as rayon, cotton, wool, and silk. Even with the same material, the rubbing state can be changed depending on the thickness and length of the thread used in the cloth. In order to make the rubbing state uniform, the thickness and length of the yarn are preferably uniform.

  In general, the diameter of the rubbing roll is preferably 10 mm to 300 mm in order to stably control its rotation. Further, by changing the diameter of the rubbing roll, the angle and area of contact with the alignment film can be adjusted.

  Moreover, although the rotation speed of the said rubbing roll is based also on the diameter of the said rubbing roll, in order to rotate a rubbing roll stably, it is preferable to set it as 100-2000 rpm. The rubbing degree can also be adjusted by changing the number of rotations of the rubbing roll.

  The stage speed of the stage and the transport speed of the vertical alignment film are generally 0.1 m / min because it is difficult to stably transport the vertical alignment film even if the transport speed of the vertical alignment film is too slow or too fast. It is preferable to control to 10 m / min. In addition, the rubbing degree can be adjusted by changing the stage speed and the conveying speed of the vertical alignment film.

  Further, in the above-described rubbing method, the push-in amount and the contact length are not particularly limited, and may be set so as to obtain a desired rubbing effect according to the yarn length of the rubbing cloth. The “push amount” is an amount by which the rubbing roll is pressed against the vertical alignment film, and is expressed by the length of the hair of the rubbing cloth pressed against the alignment film. In the above-described rubbing method, the rubbing cloth can be pressed as much as the yarn is protruding in the vertical direction. Further, the “contact length” represents a length in which the rubbing roll and the substrate are in contact with each other. The contact length can be changed to a length where the rubbing roll is in contact with the vertical alignment film when the rubbing roll is completely pressed after the rubbing roll contacts the vertical alignment film.

  As described above, in the rubbing step, the vertical alignment film is rubbed by the method as exemplified above, but the number of times the vertical alignment film is rubbed in the rubbing step is not particularly limited. That is, in the rubbing step, the vertical alignment film may be rubbed only once, or may be rubbed multiple times to control the orientation.

(II-3) Liquid crystal compound-containing composition preparation step In the liquid crystal compound-containing composition preparation step, a composition containing a rod-like polymerizable liquid crystal compound is prepared. Specifically, a solution in which the rod-like polymerizable liquid crystal compound is dissolved in an organic solvent is prepared. Examples of the rod-like polymerizable compound include <I. The rod-like polymerizable liquid crystal compound described in the film according to the present invention may be used. The organic solvent is not particularly limited as long as it can dissolve the rod-like polymerizable liquid crystal compound. For example, cyclopentanone, cyclohexanone, methyl ethyl ketone, toluene, ethyl acetate, methyl cellosolve, butyl cellosolve, isopropyl alcohol, methyl amyl ketone, xylene, acetonitrile, tetrahydrofuran, gamma-butyrolactone, dimethoxyethane, ethyl lactate, chloroform, propylene glycol monomethyl ether acetate and Examples thereof include propylene glycol monomethyl ether. These organic solvents may be used alone or in combination.

  Further, the concentration of the rod-like polymerizable liquid crystal compound in the composition is not particularly limited, but if the concentration is too low, the optically anisotropic layer becomes too thin, which is necessary for optical compensation of the liquid crystal panel. There is a tendency that optical anisotropy cannot be obtained. On the other hand, if the concentration is too high, the viscosity of the solution of the liquid crystal compound-containing composition tends to be too high, which tends to cause uneven coating film thickness. Therefore, the concentration is preferably 5 to 50 wt%. If it is within the above range, the above-described problems will not occur.

  The composition may further contain a plurality of liquid crystal compounds different from the specific polymerizable compound and / or the rod-like polymerizable liquid crystal compound.

  Examples of the liquid crystal compound include <I. Other liquid crystal compounds described in the film according to the present invention may be used.

  What is necessary is just to determine suitably content of the said liquid crystal compound according to the phase difference value calculated | required by the film obtained. Specifically, the ratio of the structural unit derived from the liquid crystal compound contained in the composition is adjusted to give a desired retardation value, and the retardation value of the obtained optical film is obtained. Based on the result, the content of the structural unit derived from the liquid crystal compound can be determined.

  Usually, the phase difference value can be controlled by changing the film thickness. However, it is difficult to control the retardation value when the incident angle is changed even if the retardation value in the normal direction can be controlled arbitrarily by controlling the film thickness alone, and the chemical structure of the rod-like polymerizable liquid crystal compound described above is difficult. I have to change it. On the other hand, by adding a structural unit derived from the liquid crystal compound, not only the retardation value in the normal direction but also the retardation value at any angle can be arbitrarily adjusted. In other words, the shape of the refractive index ellipsoid of the optically anisotropic layer can be arbitrarily controlled by adding a structural unit derived from the liquid crystal compound. However, if too much structural unit derived from the liquid crystal compound is added, the vertical alignment of the present invention may not be obtained. Therefore, for example, for a total of 100 parts by weight of the structural unit derived from the liquid crystal compound and the structural unit derived from the rod-like polymerizable liquid crystal compound, the content of the structural unit derived from the liquid crystal compound is 5 to 50 parts by weight. It is preferable to do. By setting it as the said content, the shape of the refractive index ellipsoid of the film obtained can be controlled arbitrarily.

  Examples of the polymerizable compound include <I. The polymerizable compound described in the film according to the present invention may be used. By including such a polymerizable compound in the composition, a film having arbitrary wavelength dispersion characteristics can be produced.

  What is necessary is just to determine suitably content of the said polymeric compound according to the wavelength dispersion characteristic calculated | required by the film obtained. Specifically, the ratio of the structural units derived from the polymerizable compound contained in the composition is adjusted so as to impart desired wavelength dispersion characteristics, and the retardation value of the obtained optical film is obtained. Based on the result, the content of the structural unit derived from the polymerizable compound can be determined.

  In general, a film containing no or only a small amount of the polymerizable compound exhibits positive wavelength dispersion. On the other hand, by increasing the content of the structural unit derived from the polymerizable compound, the wavelength dispersion characteristic can be arbitrarily adjusted from the normal wavelength dispersion to the reverse wavelength dispersion. When obtaining a film exhibiting reverse wavelength dispersion, for example, for a total of 100 parts by weight of the structural unit derived from the polymerizable compound and the structural unit derived from the rod-like polymerizable liquid crystal compound, the structural unit derived from the polymerizable compound The content is preferably 5 to 50 parts by weight. By setting it as the said content, the film obtained can be made into the film which shows a large retardation value while showing reverse wavelength dispersion.

  Moreover, in the manufacturing method of the film concerning this invention, the wavelength dispersion characteristic (positive wavelength dispersion-reverse wavelength dispersion) of the film obtained is performed by the composition change of the said composition. Therefore, there is an effect that the wavelength dispersion characteristic of the film can be arbitrarily adjusted by a very simple method.

  Further, the composition may contain a polymerization initiator, a polymerization inhibitor, a photosensitizer, a leveling agent, and the like.

  Examples of the polymerization initiator include <I. The polymerization initiator described in the film according to the present invention can be used. The addition amount of the polymerization initiator is an amount suitable for the polymerization reaction of the rod-like polymerizable liquid crystal compound and / or the polymerizable compound, and may be an amount that does not disturb the orientation of the rod-like polymerizable liquid crystal compound. That is, it is preferable to determine appropriately according to the types of the rod-like polymerizable liquid crystal compound, the polymerizable compound, and the polymerization initiator, and the composition of the composition. Thus, the specific numerical value of the addition amount of the polymerization initiator is not particularly limited. For example, it is 0.1 to 30 parts by weight with respect to 100 parts by weight of the rod-like polymerizable liquid crystal compound. It is preferable that there is 0.5 part by weight to 10 parts by weight. Within the above range, the rod-like polymerizable liquid crystal compound can be polymerized without disturbing the orientation of the rod-like polymerizable liquid crystal compound.

  Examples of the polymerization inhibitor include <I. The polymerization inhibitor described in the film according to the present invention can be used. The amount of the polymerization inhibitor added is not particularly limited, and the polymerization reaction of the rod-like polymerizable liquid crystal compound and / or the polymerizable compound is adjusted without disturbing the orientation of the rod-like polymerizable liquid crystal compound. It is sufficient if the amount can be increased and the stability of the optically anisotropic layer can be improved. Specifically, it is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the rod-like polymerizable liquid crystal compound. Within the above range, the polymerization of the rod-like polymerizable liquid crystal compound can be controlled and the stability of the optically anisotropic layer can be improved without disturbing the orientation of the rod-like polymerizable liquid crystal compound.

  Moreover, as said photosensitizer, <I. The photosensitizer described in the film according to the present invention can be used. Further, the addition amount of the photosensitizer is not particularly limited, and the polymerization reaction of the rod-like polymerizable liquid crystal compound and / or the polymerizable compound is increased without disturbing the orientation of the rod-like polymerizable liquid crystal compound. Any amount that can be sensitized is acceptable. Specifically, it is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the rod-like polymerizable liquid crystal compound. If it is in the said range, superposition | polymerization of a rod-shaped polymerizable liquid crystal compound can be made highly sensitive, without disturbing the orientation of a rod-shaped polymerizable liquid crystal compound.

  Further, as the leveling agent, <I. The leveling agent described in the film according to the present invention can be used. Further, the amount of the leveling agent added is not particularly limited, and the optically anisotropic layer can be smoothed or the liquid crystal compound-containing composition applied without disturbing the orientation of the rod-like polymerizable liquid crystalline compound. Any amount may be used as long as the fluidity at the time can be controlled and the crosslinking density of the rod-like polymerizable liquid crystalline compound can be adjusted. Specifically, it is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the rod-like polymerizable liquid crystal compound. Within the above range, without disturbing the orientation of the rod-like polymerizable liquid crystalline compound, the optically anisotropic layer is smoothed, the fluidity during the application of the liquid crystal compound-containing composition is controlled, or the rod-like polymerization is performed. The crosslink density of the liquid crystalline compound can be adjusted.

(II-4) Liquid crystal compound-containing composition coating step In the liquid crystal compound-containing composition coating step, the composition prepared in the liquid crystal compound-containing composition preparing step is coated on the alignment film for vertical alignment. Thereby, the coating film containing the said composition can be formed on the alignment film for vertical alignment. Here, the above composition is not prepared in the liquid crystal compound-containing composition preparation step, but is a composition having an equivalent composition, and a composition containing a separately prepared rod-like polymerizable liquid crystal compound, for example, commercially available You may use goods.

  The method for applying the composition on the alignment film for vertical alignment is not particularly limited, and a conventionally known method can be used. For example, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a CAP coating method, a die coating method, a dip coating method, a bar coating method, and a spin coating method can be used.

  Moreover, the application amount of the composition is not particularly limited, and may be applied in an appropriate amount so as to give a film thickness that gives a desired retardation value to the obtained film. As described above, the retardation value (retardation value, Re (λ)) of the obtained film can be determined by adjusting the film thickness.

  As described above, the thickness of the layer formed by applying the above composition varies depending on the retardation value of the obtained film. In the present invention, the thickness is preferably 0.1 to 10 μm, and more preferably 0.5 to 2 μm. If it is in the said range, it can be set as the retardation value of the film concerning this invention mentioned above.

  As described above, in the liquid crystal compound-containing composition coating step, the optically anisotropic layer (liquid crystal layer) is laminated on the alignment film for vertical alignment laminated on an arbitrary support substrate. Therefore, production cost can be reduced as compared with a method of manufacturing a liquid crystal cell and injecting a liquid crystal compound into the liquid crystal cell. Furthermore, it is possible to produce a film using a roll film.

(II-5) Liquid crystal compound-containing composition heating step In the liquid crystal compound-containing composition heating step, the coating film formed in the liquid crystal compound-containing composition coating step is heated. Thereby, the solvent contained in the coating film is dried, and an unpolymerized film in which the rod-like polymerizable liquid crystal compound is in an unpolymerized state can be obtained. The unpolymerized film thus obtained is also included in the present invention. The unpolymerized film exhibits a liquid crystal phase such as a nematic phase and has birefringence due to monodomain alignment. The unpolymerized film is usually oriented at a low temperature of about 10 to 120 ° C., preferably 25 to 80 ° C. Therefore, in this invention, a base material with low heat resistance can be used as a support base material mentioned above.

  In the liquid crystal compound-containing composition heating step, the method for heating the composition, the heating conditions, and the like may be any conditions as long as an unpolymerized film having the above physical properties can be obtained. Specifically, the heating temperature is preferably 10 to 120 ° C, more preferably 25 to 80 ° C. Further, the heating time is preferably 10 seconds to 60 minutes, more preferably 30 seconds to 30 minutes. As long as the heating temperature and the heating time are within the above ranges, a supporting substrate that does not necessarily have sufficient heat resistance can be used as the supporting substrate.

(II-6) Liquid Crystal Compound Polymerization Step In the liquid crystal compound polymerization step, the unpolymerized film obtained in the liquid crystal compound-containing composition heating step is polymerized and cured. Thereby, a film in which the orientation of the rod-like polymerizable liquid crystal compound is fixed, that is, a polymerized film is obtained. Therefore, it is possible to produce a polymerized film having a small change in refractive index in the plane direction of the film and a large change in refractive index in the normal direction of the film.

  The method for polymerizing the unpolymerized film is determined according to the kind of the rod-like polymerizable liquid crystal compound and the polymerizable compound. For example, the unpolymerized film can be polymerized by photopolymerization or thermal polymerization. In the present invention, it is particularly preferable to polymerize an unpolymerized film by photopolymerization. According to this, since an unpolymerized film can be polymerized at a low temperature, the heat resistance selection range of the support base material is expanded. Moreover, it becomes easy to manufacture industrially.

  The method for photopolymerizing the unpolymerized film is not particularly limited, and a conventionally known method can be used. For example, the unpolymerized film can be polymerized by irradiating the unpolymerized film with ultraviolet rays.

  Thus, in the film manufacturing method according to the present invention, no liquid crystal polymer is used as the liquid crystal compound. Further, the rod-like polymerizable liquid crystal compound can be crosslinked by photopolymerization. Therefore, there is an effect that it is not easily affected by the change in birefringence due to heat. Further, it is not necessary to use a surface treatment agent such as a surfactant in the alignment film for vertical alignment. That is, the alignment film of the film according to the present invention (vertical alignment film) has good adhesion between the support substrate and the alignment film and between the alignment film and the optically anisotropic layer. Easy to manufacture. Furthermore, according to the method for producing a film according to the present invention, it is possible to produce an optical compensation film having a desired retardation value as a thin film, as compared with a stretched film that is expected to have the same performance.

  In addition to the above steps, the film production method according to the present invention may include a step of peeling the supporting substrate in the final stage. By setting it as such a structure, the film obtained becomes a film which consists of the alignment film for vertical alignment, and an optically anisotropic layer. Moreover, in addition to the process of peeling the said support base material, the manufacturing method of the film concerning this invention may further include the process of peeling the alignment film for vertical alignment. By setting it as such a structure, the film obtained becomes a film which consists of an optically anisotropic layer. These films also satisfy nz> nx and nz> ny when the refractive indexes in the direction perpendicular to the film plane and in the film thickness direction are nx, ny, and nz, respectively. Therefore, such a film is also included in the scope of the present invention.

<III. Use of Film According to the Present Invention>
The film according to the present invention can be widely used as an optical film having excellent wavelength dispersion characteristics. Examples of the optical film include an antireflection film such as an anti-reflection (AR) film, a polarizing film, a retardation film, an elliptically polarizing film, a viewing angle widening film, and an optical compensation film for compensating a viewing angle of a transmissive liquid crystal display. be able to.

  Furthermore, the film concerning this invention can be utilized also for the flat panel display apparatus provided with the phase difference plate of a reflection type liquid crystal display and an organic electroluminescent (EL) display, and the said phase difference plate and the said optical film. The flat panel display device is not particularly limited, and examples thereof include a liquid crystal display device (LCD) and organic electroluminescence (EL).

  Thus, the film according to the present invention can be used in a wide range of applications. For example, among these, a polarizing film formed by laminating a film according to the present invention, and a flat panel display device including the film according to the present invention or the polarizing film will be described below.

(III-1) Polarizing film The embodiment of the polarizing film according to the present invention will be described below with reference to FIGS. 3 (a) to 3 (e). It is not limited.

  The polarizing film according to the present invention is a film having a polarizing function, that is, obtained by laminating directly on one side or both sides of a polarizing layer or using an adhesive or a pressure-sensitive adhesive. In the following description of FIGS. 3 and 4, the adhesive and the pressure-sensitive adhesive are collectively referred to as an adhesive.

  For example, as shown in FIGS. 3A to 3E, (1) an embodiment in which a film 1 and a polarizing layer 2 are directly bonded together (FIG. 3A), (2) film 1 And the polarizing layer 2 are bonded to each other through the adhesive layer 3 (FIG. 3B), (3) directly bonded to the film 1 and the film 1 ′, and further, the film 1 ′ and the polarizing layer 2 Embodiment (FIG. 3 (c)) and (4) film 1 and film 1 ′ were bonded together through adhesive layer 3, and polarizing layer 2 was directly bonded onto film 1 ′. Embodiment (FIG. 3 (d)) and (5) Film 1 and film 1 ′ are bonded together through adhesive layer 3, and film 1 ′ and polarizing layer 2 are bonded together through adhesive layer 3 ′. A combined embodiment (FIG. 3 (e)) is exemplified.

  In the polarizing film according to the present invention, the film according to the present invention bonded to the polarizing layer may be any of the above-described films according to the present invention. That is, any of a supporting substrate, a film made of a vertical alignment film and an optically anisotropic layer, a film made of a vertical alignment film and an optically anisotropic layer, and a film made of an optically anisotropic layer is used. You can also. In an embodiment in which a plurality of films according to the present invention are laminated in the polarizing film according to the present invention, all of the films according to the present invention may be the same or different ones may be used in combination. If it demonstrates more concretely, as a polarizing film concerning this invention, the structure shown to Fig.4 (a)-(k) is illustrated.

  4A to 4E, as the film 1 and the film 1 ′, the liquid crystal layer 11 or the liquid crystal layer 11 ′ (optically anisotropic layer) and the alignment layer 12 or the alignment layer 12 ′ (alignment film for vertical alignment) are used. The film which consists of is used. 4A to 4E show a configuration in which the film 1 and the polarizing layer 2 are directly bonded to each other (FIG. 4A), and the film 1 and the polarizing layer 2 are bonded to each other through the adhesive layer 3. Structure (FIG. 4B), film 1 and film 1 ′ directly bonded, and film 1 ′ and polarizing layer 2 directly bonded (FIG. 4C), film 1 and film 1 And the polarizing layer 2 directly bonded to the film 1 ′ (FIG. 4 (d)), and the film 1 and the film 1 ′ are bonded via the bonding layer 3. Further, a configuration (FIG. 4 (e)) in which the film 1 ′ and the polarizing layer 2 are bonded through the adhesive layer 3 ′ is shown.

4F and 4G, the film 1 and the film 1 ′ include a liquid crystal layer 11 or a film composed of the liquid crystal layer 11 ′. The film 1 includes an alignment layer 12 or an alignment film 12. '(Alignment film for vertical alignment) is not included. In FIG. 4F, the film 1 and the polarizing layer 2 are bonded together via a pair of adhesive layers 3. On the other hand, FIG.
Then, the film 1 and the film 1 ′ are bonded together via the adhesive layer 3, and the polarizing layer 2 is bonded to the outside via the adhesive layer 3 ′.

  FIG. 4 (h) shows the same structure as FIG. 4 (f). However, unlike FIG. 4F, the film 1 is formed on the surface of the support film (support base material) 13, the alignment film 12 formed on the surface of the support film 13, and the surface of the alignment film 12. A laminate (film) comprising the liquid crystal layer 11 is used.

  FIG. 4 (i) shows the same structure as FIG. 4 (g). However, unlike FIG. 4 (g), as the film 1 and the film 1 ′, the support film 13 or the support film 13 ′ and the alignment film 12 or the alignment formed on the surface of the support film 13 or the support film 13 ′. A laminate (film) including the film 12 ′ and the alignment film 12 or the liquid crystal layer 11 or the liquid crystal film 11 ′ formed on the surface of the alignment film 12 ′ is used.

  4 (j) and (k) show the same structure as FIG. 4 (g). However, of the two films, in FIG. 3 (j), a film made of the liquid crystal layer 11 ′ is used as the film 1 ′, and a film made of the liquid crystal layer 11, the alignment film 12 and the support film 13 is used as the film 1. Yes. 4 (k), a film made of the liquid crystal layer 11 ', the alignment film 12 and the support film 13 is used as the film 1', and a film made of the liquid crystal layer 11 is used as the film 1.

  The polarizing layer 2 may be a film having a polarizing function and is not particularly limited. For example, the polarizing layer 2 may be a film obtained by adsorbing iodine or a dichroic dye on a polyvinyl alcohol film or a film obtained by drawing a polyvinyl alcohol film and adsorbing iodine or a dichroic dye. it can.

  The adhesive used for the adhesive layer 3 and the adhesive layer 3 'is not particularly limited, but is preferably an adhesive having high transparency and excellent heat resistance. As such an adhesive, for example, an acrylic, epoxy, or urethane adhesive is used.

  Moreover, in the said polarizing film, as shown in FIG.3 (c)-FIG.3 (e), the film concerning this invention may laminate | stack 1 layer-3 layers as needed.

(III-2) Flat panel display device The flat panel display device concerning this invention is provided with the film or polarizing film concerning this invention. For example, a liquid crystal display device including a liquid crystal panel in which a polarizing film according to the present invention and a liquid crystal panel are bonded together, or an organic electroluminescence (hereinafter referred to as “EL”) in which a polarizing film according to the present invention and a light emitting layer are bonded together. (Also referred to as an organic EL display device).

  As embodiments of the flat panel display device according to the present invention, a liquid crystal display device and an organic EL will be described in detail below, but the present invention is not limited thereto.

[Embodiment 1]
The liquid crystal display device according to Embodiment 1 includes the liquid crystal panel shown in FIG. The liquid crystal panel is formed by bonding a polarizing film 4 and a liquid crystal panel 6 with an adhesive layer 5 interposed therebetween. According to the above configuration, when a voltage is applied to the liquid crystal panel using an electrode (not shown), the liquid crystal molecules are driven to produce an optical shutter effect.

[Embodiment 2]
The organic EL display device according to the second embodiment includes the organic EL panel shown in FIG. The organic EL panel is formed by bonding a polarizing film 4 and a light emitting layer 7 through an adhesive layer 5.

  In the organic EL panel, the polarizing film 4 functions as a broadband circularly polarizing plate. The light emitting layer 7 is at least one layer made of a conductive organic compound.

  Note that the present invention is not limited to the configurations described above, and various modifications are possible within the scope of the claims, and technical means disclosed in different embodiments are appropriately combined. Embodiments obtained in this manner are also included in the technical scope of the present invention.

  The present invention will be described more specifically based on Examples and Comparative Examples, and FIGS. 7 and 8. However, the present invention is not limited to this. Those skilled in the art can make various changes, modifications, and alterations without departing from the scope of the present invention. The wavelength dispersion characteristics in the following examples and comparative examples were performed as follows.

[Measurement of wavelength dispersion characteristics]
At a wavelength of 585.6 nm, the incident angle dependence of the retardation value of the produced film was measured using a measuring instrument (KOBRA-WR, manufactured by Oji Scientific Instruments). 7 and 8 show the phase difference value [Re (λ)] at a wavelength of 585.6 nm when the incident angle is changed with respect to the fast axis. At the same time, the front retardation value Ro (nm) of the produced film was measured at a wavelength of 585.6 nm using a measuring instrument (KOBRA-WR, manufactured by Oji Scientific Instruments).

  In addition, the incident angle dependence of the retardation value of the produced film was measured using a measuring instrument (spectral ellipsometer: M-220, manufactured by JASCO Corporation), and the refraction in the orthogonal axis direction and the film thickness direction of the film plane was measured. The rates were measured as nx, ny and nz, respectively.

[Example 1: Production of vertically oriented film]
After applying a solution for polyimide alignment film for vertical alignment (SE-5300, manufactured by Nissan Chemical Industries) on a glass substrate, annealing was performed to obtain an alignment film for vertical alignment having a thickness of 104 nm. Subsequently, a composition RMS-03-011 (manufactured by Merck & Co., Inc.) containing a rod-like polymerizable liquid crystal compound that is aligned horizontally on the horizontal alignment film and vertically aligned at the air interface without performing rubbing treatment is spinned. It was applied by a coating method and dried at 55 ° C. for 1 minute. The obtained unpolymerized film was confirmed to be monodomain by a polarizing microscope. Subsequently, ultraviolet rays were irradiated to produce a film having a thickness of 1.2 μm. The obtained film had no repellency, could be applied uniformly, had no adhesion when left in a room for 30 days, and had good adhesion.

  About the obtained film, incident angle dependence was measured by said method. The results are shown in FIG. The graph shows that the retardation value increases as the incident angle to the film increases with the incident angle of 0 ° as the center. The tilt angle of this film was shown to be 90 °.

  About the obtained film, when the front phase difference value Ro was also measured by said method, it was 0 nm. From these results, it was found that the inclination angle of the refractive index ellipsoid with respect to the film plane was 90 °.

[Examples 2 to 4: Production of inclined alignment film]
A vertical alignment polyimide alignment film (SE-5300, manufactured by Nissan Chemical Industries, Ltd.) was applied on a glass substrate, and then annealed to obtain a film having a thickness of 104 nm. The alignment film is rubbed once with rayon (YA-20-R, manufactured by Yoshikawa Chemical), followed by rod polymerization that is horizontally aligned on the horizontal alignment film and vertically aligned at the air interface. A composition RMS-03-011 (manufactured by Merck & Co., Inc.) containing a conductive liquid crystal compound was applied by spin coating and dried at 55 ° C. for 1 minute. The obtained unpolymerized film was confirmed to be monodomain by a polarizing microscope. Subsequently, ultraviolet rays were irradiated to polymerize the polymerizable liquid crystal compound, and an optical film having a film thickness of 1.2 μm was produced. The obtained film had no repellency, could be applied uniformly, had no delamination even when left indoors for 30 days, and had good adhesion.

  About the obtained film, incident angle dependence was measured by said method. In addition, the result of the film of Example 2 is shown in FIG. The results of Examples 3 and 4 are shown in Table 5. It was found that the retardation values of the films of Examples 2 to 4 increased as the incident angle to the film was increased, centering on the incident angle of -19 ° -6 ° -10 °. The tilt angles of this film were shown to be 71 °, 84 °, and 80 °, respectively.

  Moreover, front retardation value Ro was also measured about the obtained optical film by said method. As a result, the Ro of the films of Examples 2 to 4 were 18 nm, 5 nm, and 9 nm, respectively. From these results, in Examples 2 to 4, it was found from these results that the inclination angles of the refractive index ellipsoid with respect to the film plane were 71 °, 84 °, and 80 °.

[Comparative Example 1]
As a liquid crystal compound-containing composition, a film was produced in the same manner as in Example 1 except that the coating liquid shown in Table 6 was used instead of the composition RMS-03-011 (manufactured by Merck & Co., Inc.). The obtained unpolymerized film was confirmed not to be monodomain by a polarizing microscope.

  The film concerning this invention is a film which can give a high refractive index not in the plane direction of a film but in the normal line direction of a film. Therefore, the present invention can be used as an optical film having excellent wavelength dispersion characteristics such as an antireflection film such as an anti-reflection (AR) film, a polarizing film, a retardation film, an elliptically polarizing film, and a viewing angle widening film. Furthermore, the present invention can also be used for retardation plates of reflective liquid crystal displays and organic electroluminescence (EL) displays, and flat panel display devices (FPD) including such retardation plates.

FIG. 1 is a conceptual diagram showing an example of a basic cross-sectional structure of a film according to the present invention. FIG. 2 is a diagram showing the birefringence of the film according to the present invention. It is sectional drawing of the polarizing film concerning this embodiment. It is sectional drawing of the polarizing film concerning this embodiment. It is sectional drawing of the liquid crystal panel concerning this embodiment. It is sectional drawing of the organic electroluminescent panel concerning this embodiment. 4 is a graph showing the incident angle dependence of the retardation value of the optical film produced in Example 1. 4 is a graph showing the incident angle dependence of the retardation value of the optical film produced in Example 2.

Explanation of symbols

1, 1 ′ film 2, 2 ′ polarizing layer 3, 3 ′, 3 ″ adhesive layer 4 polarizing film 5 adhesive layer 6 liquid crystal panel 7 light emitting layer 11, 11 ′ liquid crystal layer (optical anisotropic layer)
12, 12 ′ alignment layer (alignment film for vertical alignment)
13, 13 'support film (support base material)
22 Index ellipsoid 23 Tilt angle 24 Vertical ellipsoid

Claims (14)

A film having an optically anisotropic layer formed on an alignment film for vertical alignment,
The optically anisotropic layer is composed of a layer containing a polymer containing a structural unit derived from a rod-like polymerizable liquid crystal compound,
The rod-like polymerizable liquid crystal compound has a property of being oriented horizontally on a horizontal alignment film as a monomer and vertically aligned at an air interface,
A film satisfying nz> nx and nz> ny, where nx, ny, and nz are refractive indexes in an orthogonal axis direction and a film thickness direction of a film plane, respectively.   The film according to claim 1, wherein the alignment film for vertical alignment is a vertical alignment film.   The film according to claim 2, wherein an inclination angle of the refractive index ellipsoid in the optically anisotropic layer with respect to the film plane is 90 ± 5 °.   The film according to claim 1, wherein the alignment film for vertical alignment is an alignment film obtained by rubbing the vertical alignment film.   The film according to claim 4, wherein an inclination angle of the refractive index ellipsoid in the optically anisotropic layer with respect to the film plane is 45 ° to 85 °. A film having an optically anisotropic layer formed on an alignment film for vertical alignment,
The optically anisotropic layer is composed of a layer containing a rod-like polymerizable liquid crystal compound,
The rod-like polymerizable liquid crystal compound has a property of being oriented horizontally on a horizontal alignment film and vertically aligned at an air interface,
A film satisfying nz> nx and nz> ny, where nx, ny, and nz are refractive indexes in an orthogonal axis direction and a film thickness direction of a film plane, respectively.   The film according to claim 1, which exhibits reverse wavelength dispersion. The optically anisotropic layer has the following formula (1):

Wherein Y represents a divalent group, s and t each independently represent an integer of 0 or 1, G1 and G2 each independently represent —CR ¹ R ² —, R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms, a halogen atom, or a hydrogen atom,
A1 and A2 each independently represent a divalent cyclic hydrocarbon group, a divalent heterocyclic group, a methylenephenylene group, an oxyphenylene group, or a thiophenylene group. A1 and A2 each have 1 to 5 carbon atoms. An alkyl group, an alkoxy group having 1 to 5 carbon atoms and a halogen atom may be bonded to each other, and B1 and B2 are each independently -CRR'-, -C≡C-, -CH = CH-,
_{-CH 2 -CH 2 -, - O} -, - S -, - C (= O) -, - C (= O) -O-,
-OC (= O)-, -OC (= O) -O-, -C (= S)-, -C (= S) -O-,
-OC (= S)-, -OC (= S) -O-, -CH = N-, -N = CH-,
-N = N-, -N (→ O) = N-, -N = N (→ O)-, -C (= O) -NR-,
_{-NR-C (= O) -} , - OCH 2 -, - NR -, - CH 2 O -, - SCH 2 -,
—CH ₂ S—, —CH═CH—C (═O) —O—, —O—C (═O) —CH═CH—, a divalent group selected from the group consisting of a single bond, R And R ′ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and X1 and X2 each independently represent the following formula (2):

(Wherein A3 represents a divalent cyclic hydrocarbon group or a heterocyclic group, B3 represents the same meaning as B1 and B2, and n represents an integer of 1 to 4)
E1 and E2 each independently represents an alkylene group having 2 to 25 carbon atoms, and E1 and E2 are further an alkyl group having 1 to 5 carbon atoms, and 1 to C1 carbon atoms. 5 alkoxy groups, halogen atoms may be bonded,
P1 and P2 represent a hydrogen atom or a polymerizable group, and at least one of P1 and P2 is a polymerizable group. )
The film of Claim 7 containing the polymer containing the structural unit derived from the polymeric compound represented by these. The optically anisotropic layer has a first surface that is in contact with the alignment film for vertical alignment, and a second surface parallel to the first surface,
9. The rod-like polymerizable liquid crystal compound located in the vicinity of the first surface is aligned horizontally, and the rod-like polymerizable liquid crystal compound located in the vicinity of the second surface is vertically aligned. The film according to any one of the above. A film comprising an optically anisotropic layer containing a polymer containing a structural unit derived from a rod-like polymerizable liquid crystal compound,
The optically anisotropic layer is
By applying a composition containing a rod-like polymerizable liquid crystal compound on the alignment film for vertical alignment, a coating film is formed,
The coating film is heated at 25 ° C. to 120 ° C. for 10 seconds to 60 minutes,
Furthermore, after cross-linking the rod-like liquid crystal compound by photopolymerization, an optically anisotropic layer obtained by peeling off the alignment film for vertical alignment,
The rod-like polymerizable liquid crystal compound has a property of being oriented horizontally on a horizontal alignment film as a monomer and vertically aligned at an air interface,
A film satisfying nz> nx and nz> ny when refractive indexes in an orthogonal axis direction and a film thickness direction of a film plane are nx, ny, and nz, respectively. A method for producing a film having an optically anisotropic layer formed on an alignment film for vertical alignment,
(A) applying a composition containing a rod-like polymerizable liquid crystal compound on the alignment film for vertical alignment;
(B) at least a step of heating the coating film formed in the step (A) at 25 ° C. to 120 ° C. for 10 seconds to 60 minutes,
A method for producing a film, wherein the rod-like polymerizable liquid crystal compound has a property of being oriented horizontally on a horizontally oriented film as a monomer and vertically oriented at an air interface.   (C) The manufacturing method of the film of Claim 11 further including the process of bridge | crosslinking the said rod-shaped liquid crystal compound by photopolymerization.   A polarizing film obtained by laminating the film according to claim 1.   A flat panel display device comprising the film according to claim 1 or the polarizing film according to claim 13.

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