JP4449533B2 - A long wound body of a broadband quarter-wave plate and a long wound body of a broadband circularly polarizing element - Google Patents

Description

  The present invention relates to a wide-band quarter-wave plate, a wide-band circularly polarizing element, and a liquid crystal display device including these, which are easy to manufacture.

The quarter-wave plate has many uses related to antireflection films and liquid crystal display devices, and has already been used in practice. In particular, a quarter wave plate is often used as a circularly polarizing plate in combination with a polarizing film. A circularly polarizing plate can be obtained by laminating a quarter-wave plate and a polarizing film so that the angle between the slow axis in the plane of the quarter-wave plate and the transmission axis of the polarizing film is substantially 45 degrees. It is done. However, most of the conventional quarter-wave plates actually can achieve a quarter-wave phase difference only at a specific wavelength.
Therefore, a stretched film (1/4 wavelength plate) that gives a phase difference of 1/4 wavelength to a specific wavelength and a stretched film (1/2 wavelength that gives a phase difference of 1/2 wavelength to a specific wavelength) A phase difference plate is known (Patent Document 1), in which each slow axis intersects with a predetermined angle. According to this, it is described that a quarter-wave phase difference can be achieved in a wide wavelength region. Such a broadband quarter-wave plate is obtained by cutting or stamping each of stretched films (a quarter-wave plate and a half-wave plate) obtained by uniaxial stretching in mutually different directions with respect to the stretching direction. These are manufactured by molding chips having the same shape and bonding them together with an adhesive or a pressure-sensitive adhesive.
However, in order to manufacture the retardation plate as described above, it is necessary to repeat the work of bonding chips formed by cutting, which is inferior in production efficiency. In addition, since cutting is performed in a direction that forms a predetermined angle with respect to the stretching direction, there is a problem in that cutting waste and the like are inevitably generated, resulting in loss of the current material.

Therefore, in Patent Document 2, the retardation value measured at a wavelength of 450 nm is 100 to 125, the retardation value measured at a wavelength of 590 nm is 120 to 160 nm, and one sheet satisfying the relationship of Re590-Re450 ≧ 2 nm. Are laminated such that the angle between the slow axis in the plane of the λ / 4 plate and the transmission axis of the linear polarizing film is substantially 45 °. A roll-shaped circularly polarizing film is disclosed. According to Patent Document 2, it is described that a conventional manufacturing process of laminating a plurality of films while strictly adjusting the angle is unnecessary.
However, since the retardation adjusting agent is used, there is a problem that costs are increased, and problems such as voids and bleed out occur in the manufacturing process.

In Patent Document 3, at least a polarizing film and a λ / 2 plate having a half-wave phase difference of birefringent light and a λ / 4 plate having a quarter wavelength are both supplied in a long length. A long circularly polarizing plate obtained by aligning a long polarizing film, a long λ / 2 plate and a long λ / 4 plate in the longitudinal direction and bonding them in this order, the absorption axis of the long polarizing film, A long circular polarizing plate characterized in that at least two of the slow axis of the long λ / 2 plate and the slow axis of the long λ / 4 plate are bonded to each other, neither parallel nor perpendicular to the longitudinal direction Is disclosed. And according to Patent Document 3, there is no need to separate the polarizing plate, the λ / 2 plate, and the λ / 4 plate individually and obliquely, and there is no unused member that has occurred near the end of the long ear, Utilization efficiency was increased. Furthermore, there was no generation of debris causing optical defects, and it was possible to prevent the adhesion of debris and to prevent entrainment of foreign matters, thereby improving the yield. Is described.
However, when making this circularly polarizing plate, it is necessary to also incline the linear polarizing plate obliquely in the longitudinal direction. Even when obtaining a long quarter-wave plate and a half-wave plate, the linear polarizing plate is inclined obliquely in the longitudinal direction. You must tilt. In addition, since the angles of inclination are different, there is a problem that even if a stretching device is provided for each member or the stretching is performed by one device, the stretching angle must be changed each time. Furthermore, since each stretching angle is different, there is a problem that the bonding angle is likely to vary, which may result in insufficient viewing angle characteristics and durability, and further improvement is desired.

JP-A-10-68816 JP 2002-22944 A Japanese Patent Laid-Open No. 2004-20827

  Therefore, an object of the present invention is to provide a long-wavelength quarter-wave plate having a higher production efficiency than the conventional one, and excellent in viewing angle characteristics and durability, and a long-winding shape of a broadband circularly polarizing element. Is to provide a body.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a specific quarter wavelength plate and a half wavelength plate. Based on this, further research has been made and the present invention has been completed.

Thus, according to the present invention,
(1) An intrinsic property having a glass transition temperature that is 10 ° C. or more and 25 ° C. or less lower than the glass transition temperature of the resin having a negative intrinsic birefringence value on both sides of the layer (I) made of a resin having a negative intrinsic birefringence value An unstretched laminate (a) obtained by laminating a layer (II) made of a resin having a positive birefringence value is stretched in a stretching direction of −8 ° to −22 ° or 8 ° to 22 ° with respect to the width direction. An elongated winding (A) of a quarter-wave plate having a slow axis in the direction of 105 ° ± 7 ° or 75 ° ± 7 ° with respect to the width direction obtained as described above,
15 ° ± 7 ° with respect to the width direction obtained by stretching the unstretched film (b) made of a transparent resin in the drawing direction of −8 ° to −22 ° or 8 ° to 22 ° with respect to the width direction, Or a long-wave body (B) of a half-wave plate having a slow axis in the direction of −15 ° ± 7 °,
A long roll (C) of a broadband quarter-wave plate that is laminated so that the slow axes of each other intersect at 60 ° ± 7 °;
(2) The long wound body (C) of the broadband quarter-wave plate according to (1), wherein the unstretched film (b) is made of a polymer resin having an alicyclic structure;
(3) A broadband circularly polarizing element obtained by laminating the long wound body (C) of the broadband quarter wave plate according to (1) or (2) on at least one surface of the long wound body of the polarizing element. Long winding body (D);
(4) The long wound body (C) of the broadband quarter-wave plate described in (1) or (2), or the long wound body of the broadband circularly polarizing element described in (3) A liquid crystal display device provided with a cut-out of (D) on at least one side of the liquid crystal cell;
And
(5) Inherent having a glass transition temperature lower by 10 ° C. or more and 25 ° C. or lower than the glass transition temperature of the resin having a negative intrinsic birefringence value on both sides of the layer (I) made of the resin having a negative intrinsic birefringence value An unstretched laminate (a) obtained by laminating a layer (II) made of a resin having a positive birefringence value is (Tg ₁ −) with respect to the glass transition temperature Tg ₁ of the resin having a negative intrinsic birefringence value. 10) Stretched in the stretching direction of −8 ° to −22 ° or 8 ° to 22 ° with respect to the width direction at a stretching temperature of from C to (Tg ₁ +20) ° C. , and 105 ° ± 7 ° with respect to the width direction. Or obtaining a long roll (A) of a quarter-wave plate having a slow axis in the direction of 75 ° ± 7 °;
An unstretched film (b) made of a transparent resin is stretched in a stretching direction of −8 ° to −22 ° or 8 ° to 22 ° with respect to the width direction, and 15 ° ± 7 ° with respect to the width direction, or Obtaining a long roll (B) of a half-wave plate having a slow axis in the direction of −15 ° ± 7 °;
A broadband quarter-wave plate for performing the step of laminating the long winding body (A) and the long winding body (B) so that their slow axes intersect at 60 ° ± 7 ° Each of the long winding bodies (C) is provided with a method for producing the same.

Since the long winding body of the broadband quarter wave plate of the present invention is obtained by laminating long winding bodies by a roll-to-roll method, the long winding body is cut out from the winding body so that the crossing angle is adjusted. The variation in the bonding angle between the laminated solids is smaller than that of the single sheets.
When obtaining the long wound body of the broadband quarter wavelength plate of the present invention, both the long wound body of the quarter wavelength plate and the long wound body of the half wavelength plate are obtained. Since the stretching direction of the oblique stretching is the same, the labor of changing the stretching angle of the tenter stretching machine can be saved. In addition, since the stretching angle with respect to the width direction can be made relatively small, for example, in the case of different distance stretching, the stretching zone can be shortened, and in the case of different speed stretching, it is necessary to extremely increase the conveying speed of one tenter clip. There is no. In addition, one step can be omitted by performing oblique stretching of both the long-wave wound body of the quarter-wave plate and the long-winding body of the half-wave plate.
Furthermore, according to the present invention, it is possible to provide a long broadband circularly polarizing element that is excellent in viewing angle characteristics and durability.

  In the present invention, the long wound body refers to one having a length of at least about 5 times the width direction of the film or laminate, preferably having a length of 10 times or more, specifically Specifically, it has a length that can be stored in a roll and stored or transported.

  In the present invention, the angle of the slow axis of the long roll (A) of the quarter wave plate or the long roll (B) of the half wave plate is the direction in which the long roll is wound. The angle between the direction of the slow axis and the width direction when viewed toward. The direction of the slow axis angle is positive in the clockwise direction from the width direction and negative in the counterclockwise direction from the width direction.

  The long wound body (A) of the quarter-wave plate used for the broadband quarter-wave plate of the present invention has an intrinsic birefringence value on both surfaces of the layer (I) made of a resin having a negative intrinsic birefringence value. 105 ° ± 7 °, or 75 ° ± 7 °, preferably 105 ° with respect to the width direction obtained by stretching the unstretched laminate (a) formed by laminating the positive resin layer (II) It has a slow axis in the direction of ± 3.5 ° or 75 ° ± 3.5 °.

  Resin having a negative intrinsic birefringence means that when light is incident on a layer in which molecules are aligned in a uniaxial order, the refractive index of light in the alignment direction is greater than the refractive index of light in the direction perpendicular to the alignment direction. A thing that gets smaller.

  Resins having a negative intrinsic birefringence include vinyl aromatic polymers, polyacrylonitrile polymers, polymethyl methacrylate polymers, cellulose ester polymers, and their multiple (binary, ternary, etc.) A polymer etc. are mentioned. These can be used alone or in combination of two or more.

  Among these, at least one selected from vinyl aromatic polymers, polyacrylonitrile polymers, and polymethyl methacrylate polymers is preferable. Of these, vinyl aromatic polymers are more preferable from the viewpoint of high birefringence.

The vinyl aromatic polymer refers to a polymer of a vinyl aromatic monomer or a copolymer of a monomer copolymerizable with a vinyl aromatic monomer.
Examples of the vinyl aromatic monomer include styrene; styrene derivatives such as 4-methylstyrene, 4-chlorostyrene, 3-methylstyrene, 4-methoxystyrene, 4-tert-butoxystyrene, and α-methylstyrene; It is done. These may be used alone or in combination of two or more.
Monomers copolymerizable with vinyl aromatic monomers include olefins such as propylene and butene; α, β-ethylenically unsaturated nitrile monomers such as acrylonitrile; acrylic acid, methacrylic acid, maleic anhydride, etc. Α, β-ethylenically unsaturated carboxylic acid; acrylic acid ester, methacrylic acid ester; maleimide; vinyl acetate; vinyl chloride;
Among vinyl aromatic polymers, a copolymer of styrene or a styrene derivative and maleic anhydride is preferable from the viewpoint of high heat resistance.

  In the present invention, the thickness of the layer made of a resin having a negative intrinsic birefringence value is not particularly limited, but is usually 5 to 400 μm, preferably 15 to 250 μm.

In the present invention, the glass transition temperature Tg ₁ of a resin having a negative intrinsic birefringence value is preferably 90 ° C. or higher, more preferably 100 ° C. or higher, from the viewpoint of excellent heat resistance during use.

  Resin having positive intrinsic birefringence means that when light is incident on a layer in which molecules are aligned in a uniaxial order, the refractive index of light in the alignment direction is greater than the refractive index of light in the direction perpendicular to the alignment direction. The one that grows.

  Examples of the resin having a positive intrinsic birefringence value include acetate resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polycarbonate resins, chain polyolefin resins, and polymer resins having an alicyclic structure. , Acrylic resins, polyvinyl alcohol resins, polyvinyl chloride resins, etc., among these, chain polyolefin resins or polymer resins having an alicyclic structure are preferred, transparency, low moisture absorption, From the viewpoints of dimensional stability, lightness, and the like, a polymer resin having an alicyclic structure is particularly preferable.

  The polymer resin having an alicyclic structure has an alicyclic structure in the main chain and / or side chain, and contains an alicyclic structure in the main chain from the viewpoint of mechanical strength, heat resistance and the like. Is preferred.

  Examples of alicyclic structures include saturated alicyclic hydrocarbon (cycloalkane) structures and unsaturated alicyclic hydrocarbon (cycloalkene) structures. From the viewpoint of mechanical strength and heat resistance, cycloalkane structures and cycloalkane structures can be used. Alkene structures are preferred, with cycloalkane structures being most preferred. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The properties of heat resistance and film formability are highly balanced and suitable. The proportion of the repeating unit containing the alicyclic structure in the polymer resin having an alicyclic structure used in the present invention may be appropriately selected according to the purpose of use, but is preferably 30% by weight or more. More preferably, it is 50% by weight or more, particularly preferably 70% by weight or more, and most preferably 90% by weight or more. When the ratio of the repeating unit having an alicyclic structure in the polymer having an alicyclic structure is in the above range, the transparency and heat resistance of the quarter-wave plate are excellent.

Specifically, the polymer resin having an alicyclic structure includes (1) a norbornene polymer, (2) a monocyclic olefin polymer, (3) a cyclic conjugated diene polymer, and (4) vinyl. Examples thereof include alicyclic hydrocarbon polymers and hydrides thereof. Among these, norbornene-based polymers are more preferable from the viewpoints of transparency and moldability.
Specific examples of the norbornene-based polymer include ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers capable of ring-opening copolymerization, hydrides thereof, and norbornene-based monomers. And addition copolymers with other monomers copolymerizable with norbornene monomers. Among these, from the viewpoint of transparency, a ring-opening (co) polymer hydride of a norbornene-based monomer is most preferable.
The polymer having the alicyclic structure is selected from known polymers disclosed in, for example, JP-A No. 2002-321302.
In the present invention, a norbornene monomer having a mesogenic group as a substituent may be used as the norbornene monomer. When this monomer is used, when a polymer obtained by polymerizing this monomer is used, the wavelength dispersibility of the (II) layer can be brought close to the wavelength dispersibility of the (I) layer. The mesogenic group means a rigid rod-like intermediate phase (liquid crystal phase) forming atomic group that exhibits liquid crystallinity in liquid crystal molecules. As the mesogenic group, there are two or more aromatic rings (including heteroaromatic rings) or alicyclic rings, and those having a linking group that connects them, a part of the aromatic ring or alicyclic hydrogen atom, or The whole thing is substituted by the substituent.

  In the present invention, the molecular weight of a resin having a positive intrinsic birefringence value is abbreviated as gel permeation chromatography (hereinafter, “GPC”) using cyclohexane (toluene when the polymer resin is not dissolved) as a solvent. The weight average molecular weight (Mw) in terms of polyisoprene or polystyrene measured in step) is usually 5,000 to 100,000, preferably 8,000 to 80,000, more preferably 10,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and the moldability of the quarter-wave plate are highly balanced and suitable.

  In the present invention, the molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of a resin having a positive intrinsic birefringence value is not particularly limited, but is usually 1.0 to 10.0, preferably 1. It is in the range of 0 to 4.0, more preferably 1.2 to 3.5.

  The polymer resin having an alicyclic structure suitably used as a resin having a positive intrinsic birefringence value has a resin component (that is, an oligomer component) having a molecular weight of 2,000 or less, preferably 5% by weight or less, preferably It is 3% by weight or less, more preferably 2% by weight or less. When the amount of the oligomer component is large, when the laminate is stretched, fine irregularities are generated on the surface or thickness unevenness occurs, resulting in poor surface accuracy.

  In order to reduce the amount of the oligomer component, the selection of the polymerization catalyst and the hydrogenation catalyst, the reaction conditions such as polymerization and hydrogenation, the temperature conditions in the step of pelletizing the resin as a molding material, etc. may be optimized. . The amount of the oligomer component can be measured by gel permeation chromatography using cyclohexane (toluene if the polymer resin does not dissolve).

  The thickness of the layer made of a resin having a positive intrinsic birefringence value used in the present invention is usually 5 to 250 μm, preferably 15 to 150 μm.

In the present invention, the glass transition temperature Tg ₂ of the resin having a positive intrinsic birefringence value used for the quarter-wave plate (A) is lower than the glass transition temperature Tg ₁ of the resin having a negative intrinsic birefringence value. It is preferably 10 ° C. or more, more preferably 20 ° C. or more.

  The layer made of a resin having a negative intrinsic birefringence value and / or the layer made of a resin having a positive intrinsic birefringence value used in the present invention has a resin having a negative intrinsic birefringence value and an intrinsic birefringence value, respectively. It consists of a resin that is positive, but the resin may include, as necessary, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, a dispersant, a chlorine scavenger, a flame retardant, and a crystallization. Nucleating agent, antiblocking agent, antifogging agent, release agent, pigment, organic or inorganic filler, neutralizing agent, lubricant, decomposing agent, metal deactivator, antifouling agent, antibacterial agent, thermoplastic elastomer, etc. These known additives can be added as long as the effects of the present invention are not impaired. The additive amount of these additives is usually 0 to 5 parts by weight, preferably 0 to 3 parts by weight with respect to 100 parts by weight of a resin having a negative intrinsic birefringence value or a resin having a positive intrinsic birefringence value. is there.

  In the quarter wave plate (A) used in the present invention, a layer (II) made of a resin having a positive intrinsic birefringence value is laminated on both sides of a layer (I) made of a resin having a negative intrinsic birefringence value. The adhesive layer (III) is provided between the layer (I) made of a resin having a negative intrinsic birefringence value and the layer (II) made of a resin having a positive intrinsic birefringence value. You may use the provided laminated body.

The adhesive layer (III) is formed from a material having affinity for both a resin having a negative intrinsic birefringence value and a resin having a positive intrinsic birefringence value used for the quarter-wave plate (A). can do. Examples of the polymer constituting the adhesive layer include ethylene- (meth) acrylate copolymers such as ethylene- (meth) methyl acrylate copolymer and ethylene- (meth) ethyl acrylate copolymer; ethylene- Examples thereof include ethylene copolymers such as vinyl acetate copolymer and ethylene-styrene copolymer, and other olefin polymers. In addition, modified products obtained by modifying these (co) polymers by oxidation, saponification, chlorination, chlorosulfonation, or the like can also be used. In the present invention, when a modified ethylene copolymer or another modified olefin polymer is used, the handling property at the time of forming the laminated structure and the heat resistance deterioration property of the adhesive force can be improved.
The thickness of the adhesive layer (III) is preferably 1 to 50 μm, more preferably 2 to 30 μm.

In the quarter-wave plate (A), said case comprising an adhesive layer has a glass transition temperature or softening point T ₃ of the adhesive, the intrinsic birefringence is a resin which is a negative glass transition temperature Tg ₁ and a unique The birefringence value is preferably lower than the glass transition temperature Tg ₂ of the resin, and more preferably 20 ° C. lower than the Tg ₁ and Tg ₂ .

The quarter wave plate (A) used in the present invention is obtained by laminating a layer (II) made of a resin having a positive intrinsic birefringence value on both surfaces of a layer made of a resin having a negative intrinsic birefringence value. It is obtained by making an unstretched laminate (a) and then stretching it.
Examples of methods for obtaining the unstretched laminate (a) include coextrusion T-die method, coextrusion inflation method, coextrusion molding method such as coextrusion lamination method, film lamination molding method such as dry lamination, and base resin film For example, a known method such as a coating molding method in which a resin solution is coated can be appropriately used. Among these, a molding method by coextrusion is preferable from the viewpoints of production efficiency and that volatile components such as a solvent do not remain in the film.
The extrusion temperature can be appropriately selected according to the type of the resin having a negative intrinsic birefringence value, the resin having a positive intrinsic birefringence value, and the adhesive used as necessary.

  The method of stretching the unstretched laminate (a) is not particularly limited, but a method of stretching obliquely is preferable. As a method of obliquely stretching, a tenter stretching machine that can add feed force, pulling force, or take-up force at different speeds in the horizontal or vertical direction, or a feed force or pulling force at constant horizontal speed in the horizontal or vertical direction. Alternatively, there may be mentioned a method of performing oblique stretching using a tenter stretching machine in which a take-off force can be applied and the moving distance is the same and the stretching angle θ can be fixed or the moving distance is different. According to this obliquely stretching method, a long wound body of the quarter-wave plate (A) having a slow axis in the direction of 105 ° ± 7 ° or 75 ° ± 7 ° with respect to the width direction is obtained. be able to.

FIG. 1 shows an example of an oblique stretching apparatus. In this oblique stretching apparatus, 1 indicates an unstretched film (in the present invention, it indicates an unstretched laminate (a) or an unstretched film (b) made of a polymer resin having an alicyclic structure), and 2 indicates a film. 2-1 is the right film holding start point, 2-2 is the left film holding start point, 3-1 is the trajectory of the right film holding means, and 3-2 is the left film holding point. 4 is a tenter, 5-1 is a film holding end point on the right side, 5-2 is a film holding end point on the left side, and 6 is an obliquely stretched film.
In the oblique stretching apparatus, the feeding speed of the obliquely stretched film fed from the oblique stretching apparatus is the same as the feeding speed of the unstretched film fed to the oblique stretching apparatus. larger than the moving distance of the other end an end distance of movement of the direction, i.e. the width direction 7-2 Cartesian the feeding direction 7-1. However, the linear velocity at both ends of the unstretched film is the same at both ends.
In this oblique stretching apparatus, the unstretched film fed in the direction 7-1 is chucked by the left and right film holding start points 2-1 and 2-2 at both ends in the width direction. Although the linear velocity of the film by the left and right film holding means 3-1 and 3-2 is constant, the film moving distance by the left film holding means 3-2 is the film by the right film holding means 3-1. It is set larger than the moving distance. Therefore, the axial direction of the film to be fed, that is, the traveling direction curves in the right side in FIG. At the film holding end point, the stretched direction 8 becomes an obliquely stretched film 6 having a stretching angle 8 of θ with respect to the width direction 7-2 of the film, and the film is fed out.

In the case of performing the oblique stretching method, the stretching angle θ with respect to the width direction of the unstretched laminate (a) is preferably −8 ° to −22 °, or 8 ° to 22 °, and −10 °. More preferably, it is carried out in the range of -20 ° or 10 ° -20 °. By setting the stretching angle θ in the above range, the obtained ¼ wavelength plate (A) has a slow axis in the direction of 105 ± 7 ° or 75 ± 7 ° with respect to the width direction. it can.
In the present invention, the stretching angle θ is an angle with respect to the width direction of the unstretched laminate (a), and positive in the clockwise direction and negative in the counterclockwise direction.
FIG. 2 is a conceptual diagram showing the stretching angle θ of the unstretched laminate (a). In FIG. 2, A is the traveling direction of the unstretched laminate (a), B is the width direction of the unstretched laminate (a), C ₁ is 8 ° to the stretching angle θ is clockwise unstretched laminate (a) stretching direction when it is through 22 °, C ₂ stretching direction when the stretching angle θ of unstretched laminate (a) is -8 ° through 22 ° clockwise, D is unstretched laminate (a ) In the positive direction with respect to the width direction, and E indicates the negative direction with respect to the width direction of the unstretched laminate (a). Incidentally, the stretching direction is either _C 1, _{C 2.}

The stretching temperature of the unstretched laminate (a) is (Tg ₁ −10) ° C. to (Tg ₁ −10) ° C. to (glass transition temperature Tg ₁ of the resin having a negative intrinsic birefringence value used for the quarter-wave plate (A). Tg ₁ +20) ° C. is preferable, and a range of (Tg ₁ −5) ° C. to (Tg ₁ +15) ° C. is more preferable.
In the quarter wave plate (A), the glass transition temperature Tg ₂ of the resin having a positive intrinsic birefringence value is made lower than the glass transition temperature Tg ₁ of the resin having a negative intrinsic birefringence value, and the unstretched By setting the stretching temperature of the laminate (a) in the above range, the in-plane retardation Re (I) of the layer (I layer) made of a resin having a negative intrinsic birefringence and a resin having a positive intrinsic birefringence value The relationship of Re (I)> Re (II) can be satisfied with the in-plane retardation Re (II) of the layer made of (II layer). And in this way, in the obtained quarter wave plate (A), it has a slow axis in the direction orthogonal to the stretching direction, and in the direction of 105 ° ± 7 ° or 75 ° ± 7 ° with respect to the width direction. Can have a slow axis. By doing so, the wavelength dispersion of the quarter wave plate (A) can be adjusted as appropriate, and the viewing angle characteristics can be improved by adjusting the birefringence of each layer according to the characteristics of the liquid crystal cell. it can.

  The draw ratio of the unstretched laminate (a) is usually 1.05 to 30 times, preferably 1.2 to 10 times. If the draw ratio is out of the above range, the orientation may be insufficient and the refractive index anisotropy and thus the retardation may be insufficiently exhibited, or the unstretched laminate may be broken.

The content of the residual volatile component of the quarter wave plate (A) is not particularly limited, but is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and further preferably 0.02% by weight or less. It is. When the content of residual volatile components exceeds 0.1% by weight, the volatile components are released to the outside during use, causing dimensional changes in the quarter-wave plate (A) and generating internal stress. As a result, the phase difference may become uneven. Therefore, when the content of the volatile component of the quarter-wave plate (A) is in the above range, the stability of the optical characteristics such that display unevenness of the display of the liquid crystal display device does not occur even when used for a long time is excellent. .
The volatile component is a substance having a molecular weight of 200 or less contained in a small amount in the quarter-wave plate (A), and examples thereof include residual monomers and solvents. The content of the volatile component can be quantified by analyzing the quarter wavelength plate (A) by gas chromatography as the sum of the substances having a molecular weight of 200 or less contained in the quarter wavelength plate (A).

  The thickness of the quarter wave plate (A) is usually 10 to 300 μm, preferably 30 to 200 μm.

  In the quarter wave plate (A) used in the present invention, when the retardation measured at a wavelength of 550 nm is Re (550), a value obtained by dividing this by a wavelength λ (here, λ = 550) Re (550) / λ Is preferably 0.23 to 0.27, and more preferably 0.24 to 0.26.

In the quarter wave plate (A) used in the present invention, the variation of the slow axis in the in-plane direction is preferably within 5 °, more preferably within 3 °, and preferably within 1 °. Further preferred.
By setting the variation of the slow axis in the in-plane direction within the above range, when the wide-band quarter-wave plate (C) of the present invention is used as a retardation film and bonded to a polarizing plate in a liquid crystal display device, It is possible to provide a good liquid crystal display free from color unevenness and color loss.
The variation of the slow axis is the variation of each measured value with respect to the arithmetic average value of the measured values when the slow axis is measured at several points.

  The long roll (B) of the half-wave plate used for the broadband quarter-wave plate (C) of the present invention is in the width direction obtained by stretching the film (b) made of a transparent resin. It has a slow axis in the direction of 15 ° ± 7 ° or −15 ° ± 7 °.

  The transparent resin used for the long roll (B) of the half-wave plate is not particularly limited as long as it has a thickness of 1 mm and a total light transmittance of 80% or more, and is an acetate type such as triacetyl cellulose. Resins, polyester resins, polyethersulfone resins, polycarbonate resins, chain polyolefin resins, polymer resins having an alicyclic structure, acrylic resins, polyvinyl alcohol resins, polyvinyl chloride resins, etc. However, from the viewpoint of easy matching with the wavelength dispersibility of the layer (I) made of a resin having a negative intrinsic birefringence value of the quarter-wave plate (A), a polycarbonate resin or a polymer resin having an alicyclic structure Is preferred.

  The unstretched film (b) made of a transparent resin to be used is made of a transparent resin, and the resin is optionally provided with an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, and an antistatic agent. Agents, dispersants, chlorine scavengers, flame retardants, crystallization nucleating agents, antiblocking agents, antifogging agents, mold release agents, pigments, organic or inorganic fillers, neutralizing agents, lubricants, decomposition agents, metal inertness Known additives such as an agent, an antifouling material, an antibacterial agent and a thermoplastic elastomer can be added within a range not impairing the effects of the present invention. The addition amount of these additives is usually 0 to 5 parts by weight, preferably 0 to 3 parts by weight with respect to 100 parts by weight of the transparent resin.

The half-wave plate (B) used in the present invention is obtained by stretching an unstretched film (b) made of a transparent resin. The method for obtaining the unstretched film (b) made of a transparent resin is not particularly limited, and a known molding method such as a melt extrusion molding method, a press molding method, a hot melt molding method such as an inflation method, or a solution casting method is used. Can be adopted.
Each molding condition may be appropriately adjusted according to the glass transition temperature of the transparent resin to be used, the solvent, and the like.

  Examples of the method for stretching the unstretched film (b) include the same methods as those described in the method for stretching the unstretched laminate (a). Of these, the oblique stretching method is preferred. According to this obliquely stretching method, a long-winding body is obtained by using a half-wave plate (B) having a slow axis in the direction of 15 ° ± 7 ° or −15 ° ± 7 ° with respect to the width direction. be able to.

  When the oblique stretching method is performed, the stretching angle θ with respect to the width direction of the unstretched film (b) is preferably −8 ° to −22 °, or 8 ° to 22 °, and −10 ° to More preferably, it is carried out in the range of −20 ° or 10 ° to 20 °. By setting the stretching angle θ in the above range, the slow axis of the obtained half-wave plate can be given in the direction of 15 ° ± 7 ° or −15 ° ± 7 ° with respect to the width direction. .

The stretching temperature of the unstretched film (b) is from (Tg _b −10) ° C. to (Tg _b −10) when the glass transition temperature of the resin having a positive intrinsic birefringence value used for the half-wave plate (B) is Tg _b. Tg _b +20) ° C. is preferable, and a range of (Tg _b −5) ° C. to (Tg _b +15) ° C. is more preferable.

  The draw ratio of the unstretched film (b) is usually 1.05 to 30 times, preferably 1.2 to 10 times. If the draw ratio is out of the above range, the orientation may be insufficient and the refractive index anisotropy and thus the retardation may be insufficiently exhibited, or the unstretched laminate may be broken.

  The content of the residual volatile component in the half-wave plate (B) is not particularly limited, but is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and further preferably 0.02% by weight or less. It is. When the content of residual volatile components exceeds 0.1% by weight, the volatile components are released to the outside during use, causing dimensional changes in the half-wave plate (B) and generating internal stress. As a result, the phase difference may become uneven. Therefore, when the content of the volatile component of the half-wave plate (B) is in the above range, the stability of the optical characteristics such that display unevenness of the display of the liquid crystal display device does not occur even when used for a long time is excellent. .

  The thickness of the long rolled body (B) of the half-wave plate is usually 10 to 300 μm, preferably 30 to 200 μm.

  In the long roll (B) of the half-wave plate used in the present invention, when the retardation measured at a wavelength of 550 nm is Re (550), the value obtained by dividing this by the wavelength λ (here, λ = 550) Re (550) / λ is preferably 0.48 to 0.52, and more preferably 0.49 to 0.51.

In the long wound body (B) of the half-wave plate used in the present invention, the variation of the slow axis in the in-plane direction is preferably within 5 °, more preferably within 3 °. More preferably, it is within the range of °.
By setting the variation of the slow axis in the in-plane direction within the above range, when the wide-band quarter-wave plate (C) of the present invention is used as a retardation film and bonded to a polarizing plate in a liquid crystal display device, It is possible to provide a good liquid crystal display free from color unevenness and color loss.
The variation of the slow axis is the variation of each measured value with respect to the arithmetic average value of the measured values when the slow axis is measured at several points.

  The long wound body (C) of the broadband quarter wavelength plate of the present invention includes a long wound body (A) of the quarter wavelength plate and a long wound body (A) of the half wavelength plate ( B) is laminated.

The lamination of the long winding body (A) of the quarter wave plate and the long winding body (B) of the half wave plate will be described with reference to the drawings.
FIG. 3 is a view showing a long-wave wound body (A) of a quarter-wave plate and a long-winding body (B) of a half-wave plate used in the present invention.
FIG. 4 is a diagram illustrating an example of a stacking mode of a long-wave wound body (A) of a quarter-wave plate and a long-winding body (B) of a half-wave plate by a roll-to-roll method. .
As shown in FIG. 3, a quarter-wave plate long roll (A) and a half-wave plate length obtained by stretching the unstretched laminate (a) and the unstretched film (b), respectively. The wound body (B) is wound up into a wound roll shape.
In FIG. 3, 9-1 represents a long winding body (A) of a quarter-wave plate, 10-1 represents a long winding body (B) of a half-wave plate, and 9-2 represents 1 / 4 wavelength plate (A) slow axis direction, 9-3 is the angle between the width direction of the quarter wavelength plate (A) and the slow axis (when the angle is positive), 10-2 is 1 / The slow axis direction 10-3 of the two-wavelength plate (B) represents an angle (when the angle is positive) formed by the width direction of the half-wave plate (B) and the slow axis.

Subsequently, as shown in FIG. 4, the quarter-wave plate long roll (A) 9-1 and the half-wave plate long roll (B) 10-1 are respectively sandwiched rolls. It is clamped by 12 and 13, runs on the feed roll 11, and is pressed and stacked by the pressing roll 14. Such a method of laminating is called a roll-to-roll method. At this time, when laminating the long wound body (A) of the quarter wavelength plate or the long wound body (B) of the half wavelength plate, the long wound body of the quarter wavelength plate. In (A), the slow axis is in the direction of 105 ° ± 7 ° with respect to the width direction and the long winding body of the half-wave plate (B) with the slow axis in the width direction. A surface in the direction of 15 ° ± 7 °, or a surface in which the slow axis is in the direction of 75 ° ± 7 ° with respect to the width direction in the long roll (A) of the quarter-wave plate In the long wound body (B) of the two-wavelength plate, a surface in which the slow axis is in the direction of −15 ° ± 7 ° with respect to the width direction is bonded. By doing so, the slow axis of the quarter wavelength plate (A) and the slow axis of the half wavelength plate (B) can be crossed at 60 ° ± 7 °.
At this time, an adhesive or a pressure-sensitive adhesive may be applied to the joining surface of the two long wound bodies wound up. Examples of the adhesive or pressure-sensitive adhesive include acrylic, silicone, polyester, polyurethane, polyether, rubber, and the like. Among these, an acrylic type is preferable from the viewpoint of heat resistance and transparency.

  The long roll (C) of the broadband quarter-wave plate of the present invention is a quarter-wave plate having a slow axis in the direction of 105 ° ± 7 ° or 75 ° ± 7 ° with respect to the width direction. And a half-wave plate (B) having a slow axis in the direction of 15 ° ± 3 ° or −15 ° ± 7 ° with respect to the width direction (B) Are stacked so that their slow axes intersect at 60 ° ± 7 °, preferably 60 ° ± 3.5 °.

  The long wound body (C) of the broadband quarter-wave plate of the present invention has a wide wavelength region, for example, a region of λ = 450 to 650 nm, and the value of Re (λ) / λ is 0.24 to 0. Preferably in the range of .26. When the value of Re (λ) / λ is within the above range, a more excellent function as a quarter wavelength plate can be achieved in the visible light region with a wavelength of 450 to 650 nm.

  The long wound body (D) of the broadband circularly polarizing element of the present invention has the long wound body (C) of the broadband quarter wavelength plate of the present invention on at least one side of the long wound body of the polarizing element. Laminated.

Examples of the polarizing element used in the broadband circular polarizing element (D) of the present invention include a polarizer and a polarizing plate.
A polarizing plate consists of what adhered the transparent protective film used as a protective layer to the one or both sides of the polarizer which consists of a dichroic substance containing polyvinyl-alcohol-type polarizing film etc. through the suitable contact bonding layer.
As a polarizer, for example, a film made of a suitable vinyl alcohol-based polymer according to the prior art such as polyvinyl alcohol or partially formalized polyvinyl alcohol, a dyeing treatment with a dichroic substance made of iodine or a dichroic dye, a stretching treatment In addition, an appropriate treatment such as a crosslinking treatment can be performed in an appropriate order and method, and an appropriate material that transmits linearly polarized light when natural light is incident can be used. In particular, those excellent in light transmittance and degree of polarization are preferable. Moreover, the polarizer to be used is preferably not subjected to a stretching treatment in an oblique direction. The thickness of the polarizer is generally 5 to 80 μm, but is not limited thereto.

As the film material constituting the transparent protective film, an appropriate transparent film can be used. Among them, a film made of a polymer excellent in transparency, mechanical strength, thermal stability, moisture shielding property, etc. is preferably used. Is as its polymer over, heavy with such acetate resins and polyester resins triacetyl cellulose, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, an alicyclic structure Examples include coalescing resins, acrylic resins, etc. Among them, acetate resins or polymer resins having an alicyclic structure are preferable in terms of low birefringence, transparency, low hygroscopicity, dimensional stability, lightness, etc. In view of the above, a polymer resin having an alicyclic structure is particularly preferable.
The thickness of the transparent protective film is arbitrary, but is generally 500 μm or less, preferably 5 to 300 μm, particularly preferably 5 to 150 μm for the purpose of reducing the thickness of the polarizing plate.

  In the broadband circularly polarizing element (D) of the present invention, the polarizer and the half-wave plate (B) constituting the broadband quarter-wave plate (C) of the present invention are laminated so as to be in contact with each other. The half-wave plate (B) can also serve as a transparent protective film for the polarizer, and the thickness of the member can be reduced.

  Another layer may be provided on one side or both sides of the polarizing element used in the broadband circularly polarizing element (D) of the present invention. Examples of the other layers include a hard coat layer, an antireflection layer, an antiglare treatment layer, and an antifouling layer.

Lamination | stacking with a broadband quarter wavelength plate (C) and a polarizing element can be bonded together using appropriate adhesion means, such as an adhesive agent and an adhesive. Examples of the adhesive or pressure-sensitive adhesive include acrylic, silicone, polyester, polyurethane, polyether, rubber, and the like. Among these, an acrylic type is preferable from the viewpoint of heat resistance and transparency.
The broadband quarter-wave plate (C) and the polarizing element are laminated so that the slow axis of the broadband quarter-wave plate (C) and the transmission axis of the polarizing element are parallel or orthogonal. Examples of the laminating method include a roll-to-roll method.
When laminating the broadband quarter-wave plate (C) and the polarizing element, even if the polarizing element is in contact with the quarter-wave plate (A) of the broadband quarter-wave plate (C), the half-wave plate (B) may touch.
The broadband circularly polarizing element of the present invention has a thickness of usually 100 to 700 μm, preferably 200 to 600 μm.

  The broadband circularly polarizing element of the present invention, when natural light is incident from the polarizing plate side, emits circularly polarized light from the ¼ wavelength plate side and functions as a circularly polarizing plate, and from the ¼ wavelength plate side. When the circularly polarized light is incident, it is linearly polarized by the quarter wave plate, which is incident on the polarizing plate and functions as a linearly polarized light forming plate.

  The function as the former circularly polarized light forming plate is useful as an antireflection filter for suppressing surface reflection of a liquid crystal display or the like. The latter function as a linearly polarized light forming plate is useful for forming a system for improving the luminance of a liquid crystal display device when used in combination with a backlight provided with a circularly polarized light forming plate made of cholesteric liquid crystal or the like. By using the circularly polarizing plate according to the present invention, a liquid crystal display device that is bright and excellent in contrast, wide in viewing angle, and highly durable can be obtained.

The liquid crystal display device of the present invention is obtained by cutting out the long wound body (C) of the broadband quarter-wave plate of the present invention or the long wound body (D) of the broadband circularly polarizing element of the present invention. Is provided on at least one side of the liquid crystal cell.
The liquid crystal display device of the present invention is formed with a suitable structure according to the prior art, such as a transmissive type, a reflective type, or a transmissive / reflective type in which a polarizing plate is arranged on one or both sides of a liquid crystal cell. Can do. The liquid crystal modes used in the liquid crystal cell include TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, HAN (Hybrid Alignment Nematic) type, VA (Vertical Alignment), MVA (Multi-type Inlet). Plane Switching) type, OCB (Optical Compensated Bend) type, and the like.

  A liquid crystal display device is generally formed by appropriately assembling components such as a polarizing plate, a liquid crystal cell, and a backlight, a reflector, and a phase difference compensator as necessary, and incorporating a drive circuit. In the invention, there is no particular limitation except that the above-described broadband quarter-wave plate (C) and broadband circularly polarizing element (D) are used, and a liquid crystal display device can be formed according to the prior art. Further, when forming a liquid crystal display device, for example, a suitable layer such as a brightness enhancement film, a prism array sheet, a lens array sheet, a light guide plate, a light diffusion plate, a backlight, a reflection plate, a transparent electrode, etc. Alternatively, two or more layers can be arranged.

  In the liquid crystal display device of the present invention, in order to adhere the liquid crystal cell and the long quarter-wave plate (C) or broadband circular polarizing element (D) of the broadband quarter wave plate of the present invention, An agent layer can also be provided. The pressure-sensitive adhesive layer can be appropriately formed using a conventionally known pressure-sensitive adhesive such as acrylic. In particular, the moisture absorption rate is low in terms of prevention of foaming and peeling phenomena due to moisture absorption, deterioration of optical properties due to thermal expansion differences, prevention of warping of liquid crystal cells, and formation of liquid crystal display devices with high quality and durability. The pressure-sensitive adhesive layer is preferably low and excellent in heat resistance. Moreover, it can also be set as the adhesive layer etc. which contain microparticles | fine-particles and show light diffusibility.

  When the pressure-sensitive adhesive layer provided on the polarizing plate is exposed on the surface, it is preferable to temporarily cover with a separator for the purpose of preventing contamination until the pressure-sensitive adhesive layer is put to practical use. The separator is formed by, for example, a method in which a release coat with an appropriate release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide is provided on an appropriate thin leaf according to the above-described transparent protective film or the like. be able to.

  In addition, each layer such as the polarizer, the transparent protective film, the optical layer, and the adhesive layer described above absorbs ultraviolet rays such as salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, and nickel complex compounds. It may be provided with ultraviolet absorbing ability by an appropriate method such as a method of treating with an agent.

The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Parts and% are based on weight unless otherwise specified.
Evaluation in the present invention is performed by the following method.
(1) Retardation Measured using an ellipsometer (M-150, manufactured by JASCO Corporation).
(2) Slow axis and its variation Measured using an automatic birefringence meter (manufactured by Oji Scientific Instruments, KOBRA-21).
The slow axis and its variation are determined by measuring the slow axis at 10 mm intervals in the width direction of the film or laminate, obtaining the arithmetic average value of the measured values, and determining the measured value variation from the average value.
(3) Broadband property and viewing angle characteristics of circularly polarizing element Two circularly polarizing elements are prepared and left under the following environment (I) or environment (II).
Environment (I): left for 30 days in an environment of temperature 25 ° C. and humidity 40% Environment (II): left for 30 days in an environment of temperature 25 ° C. and humidity 80% Then, the circularly polarizing element left in each environment The following procedure is used for evaluation.
The broadband property is evaluated according to the following criteria by placing a circularly polarizing element left in each environment on a diffuse reflector and visually observing the color reflected from the front.
Good: Reflection color is black Defective: Reflection color is bright and blue. On the other hand, the viewing angle characteristic is that the circularly polarized light element left in each environment is placed on the diffuse reflector and the reflection color is 45 degrees diagonally from the front. The brightness and color unevenness are visually observed and evaluated according to the following criteria.
Good: There is no change in reflected color and brightness between the front and 45 degrees oblique, and there is no color unevenness.
Defect: There is a change in reflected color and brightness between the front and 45 degrees oblique, and there is uneven color.

(Production Example 1) Production of polymer resin having alicyclic structure To 500 parts of dehydrated cyclohexane, 0.82 part of 1-hexene, 0.15 part of dibutyl ether, and 0.30 part of triisobutylaluminum were added under a nitrogen atmosphere. After mixing in a reactor at room temperature and maintaining at 45 ° C., tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (dicyclopentadiene, hereinafter abbreviated as “DCP”). ) 170 parts, 8-ethylidene-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -dodec-3-ene (ethylidenetetracyclododecene, hereinafter abbreviated as “ETD”) 30 parts norbornene monomer mixture and tungsten hexachloride (0.7% toluene solution) ) 40 parts was continuously added over 2 hours for polymerization. To the polymerization solution, 1.06 part of butyl glycidyl ether and 0.52 part of isopropyl alcohol were added to inactivate the polymerization catalyst, and the polymerization reaction was stopped.

  Next, 35 parts of cyclohexane is added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and 5 parts of a nickel-alumina catalyst (manufactured by JGC Chemical Co., Ltd.) is added as a hydrogenation catalyst. The mixture was heated to 200 ° C. while being stirred and pressurized to 5 MPa, and then reacted for 4 hours to obtain a reaction solution containing 20% of a DCP / ETD ring-opening copolymer hydride.

  When the copolymerization ratio of each norbornene monomer in the obtained ring-opening copolymer hydride was calculated from the composition of residual norbornenes in the solution after polymerization (by gas chromatography method), DCP / It was almost equal to the charged composition at ETD = 85/15 (weight ratio). The norbornene-based polymer 1 had a weight average molecular weight (Mw) of 35,000, a molecular weight distribution of 2.1, and a content of a resin component having a molecular weight of 2,000 or less was 0.7% by weight. The hydrogenation rate was 99.9% and Tg was 105 ° C.

  After removing the hydrogenation catalyst by filtration, an antioxidant (trade name: Irganox 1010, manufactured by Ciba Specialty Chemicals) was added to the resulting solution and dissolved (the amount of the antioxidant added) 0.1 parts per 100 parts polymer).

  Subsequently, cyclohexane and other volatile components, which are solvents, are removed from the solution at a temperature of 270 ° C. and a pressure of 1 kPa or less by using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.). A hydrogenated DCP / ETD ring-opening copolymer (hereinafter abbreviated as “norbornene polymer 1”), which is an example of a polymer resin having a structure, was obtained.

(Production Example 2) Manufacture of long roll A-1 of quarter-wave plate Layer (II layer) composed of norbornene polymer 1 obtained in Production Example 1, styrene-maleic acid copolymer (Nova)・ Product made by Chemical Co., Ltd., trade name “Daylark D332”, glass transition temperature 130 ° C., oligomer component content 3 wt%) (I layer), and modified ethylene-vinyl acetate copolymer (Mitsubishi Chemical Co., Ltd., II layer (30 μm) -III layer (6 μm) -I layer (150 μm) -III layer (6 μm)-having an adhesive layer (III layer) consisting of trade name “Modic AP A543”, Vicat softening point 80 ° C. A long wound body a-1 of an unstretched laminate of the II layer (30 μm) was obtained by coextrusion molding.
Next, the long wound body a-1 of this unstretched laminate was − with respect to the width direction at a stretching temperature of 138 ° C., a stretching ratio of 1.5 times, and a stretching speed of 115% / min, using a tenter stretching machine. Diagonal stretching was performed in the direction of 13 °, and this was wound up in a roll shape over 3000 m to obtain a long wound body A-1.
When the retardation Re (550) at a wavelength of 550 nm of the obtained long roll A-1 was measured, it was 137.2 nm, and Re (550) /λ=0.249. Therefore, this long winding A-1 was used as a long winding of a quarter wave plate. Further, the slow axis direction of this long wound body A-1 was 103 ° with respect to the width direction, and the variation of the slow axis was ± 0.1 °. In addition, the surface in which the slow axis of this long wound body A-1 was 103 ° ± 0.1 ° with respect to the width direction was defined as the A surface.

(Production Example 3) Production of long roll A-2 of quarter-wave plate In Production Example 2, the norbornene polymer 1 used for the II layer was changed to norbornene polymer 2 (manufactured by Nippon Zeon Co., Ltd., trade name “ The polymer used for the adhesive layer (III layer) instead of ZEONOR 1060 ”, glass transition temperature 105 ° C.) is a maleic acid-modified olefin polymer (trade name“ Modic AP F534A ”manufactured by Mitsubishi Chemical Corporation, Vicat softening point 55 ° C. In the same manner as in Production Example 2, coextrusion was performed, and the II layer (26 μm) -III layer (7 μm) -I layer (38 μm) -III layer (7 μm) -II layer (26 μm) A long wound body a-2 of the stretched laminate was obtained.
Next, the long wound body a-2 of the unstretched laminate was stretched 9 times in the width direction at a stretching temperature of 134 ° C., a stretching ratio of 1.4 times, and a stretching speed of 180% / min using a tenter stretching machine. The film was obliquely stretched in the direction of ° and rolled up in a roll shape over 3000 m to obtain a long wound body A-2.
The retardation Re (550) at a wavelength of 550 nm of the obtained long roll A-2 was measured to be 137.2 nm, and Re (550) /λ=0.249. Therefore, this long winding body A-2 was used as a long winding body of a quarter wave plate. Further, the slow axis direction of this long winding A-2 was 99 ° with respect to the width direction, and the variation of the slow axis was ± 0.1 °.
In addition, the surface in which the slow axis of this long wound body A-2 was 99 ° ± 0.1 ° with respect to the width direction was defined as the A surface.

(Manufacture example 4) Manufacture of the long winding body B-1 of a half-wave plate The pellet of a norbornene-type polymer (The Nippon Zeon company make, "ZEONOR1420", glass transition temperature is 136 degreeC) is distribute | circulated air. And dried at 100 ° C. for 4 hours using a hot air dryer. And this pellet is extruded using a T-die type film melt extrusion molding machine having a resin melt kneader equipped with a 50 mmφ screw, under the conditions of a molten resin temperature of 260 ° C. and a T-die width of 650 mm. An unstretched long wound body b-1 of 100 μm was obtained.
Using a tenter stretching machine, this unstretched long wound body b-1 is stretched at a stretching temperature of 142 ° C., a stretching ratio of 1.5 times, and a stretching speed of 150% / min with respect to the width direction of the long wound body. The film was obliquely stretched in the direction of 16 ° and wound up into a roll shape over 3000 m to obtain a long wound body B-1.
The retardation Re (550) at a wavelength of 550 nm of the obtained long roll B-1 was measured to be 274.8 nm, and Re (550) /λ=0.500. Therefore, this long winding body B-1 was used as a long winding body of a half-wave plate. Further, the slow axis direction of this long wound body B-1 was 16 ° with respect to the width direction, and the variation of the slow axis was ± 0.1 °.
In addition, the surface where the slow axis of this long wound body B-1 was 16 ° ± 0.1 ° with respect to the width direction was defined as the B surface.

(Manufacture example 5) Manufacture of the long wound body B-2 of a half-wave plate The polycarbonate-type resin (molecular weight 80,000, intrinsic birefringence value 0.104) obtained by condensation of phosgene and bisphenol A, An unstretched long wound body b-2 having a thickness of 90 μm was obtained by a solution casting method using methylene chloride as a solvent.
Using a tenter stretching machine, this unstretched long wound body b-2 is stretched at a temperature of 175 ° C., a magnification of 1.2 times, and a stretching speed of 150% / min with respect to the width direction of the long wound body. Uniaxial stretching was performed in an oblique 18 ° direction, and this was wound up in a roll shape over 3000 m to obtain a long wound body B-2.
When the retardation Re (550) at a wavelength of 550 nm of the obtained long roll B-2 was measured, it was 274.8 nm, and Re (550) /λ=0.500. Therefore, this long winding body B-2 was used as a long winding body of a half-wave plate. The long axis B-2 had a slow axis direction of 18 ° with respect to the width direction and a slow axis variation of ± 0.1 °.
In addition, the surface where the slow axis of this long wound body B-2 was 18 ° ± 0.1 ° with respect to the width direction was defined as the B surface.

(Example 1) Manufacture of broadband quarter-wave plate C-1 The long winding body A-1 obtained in Production Example 2 and the long winding body B-1 obtained in Production Example 4 are drawn out, respectively. Then, lamination was performed by a roll-to-roll method as shown in FIG. 3 so that the A surface and the B surface were in contact with each other to obtain a 3000 m long wound body C-1.
This wound body C-1 has a retardation value Re (450) at a wavelength λ = 450 nm of 108 nm (Re (λ) /λ=0.24), and a retardation value Re (550) at a wavelength λ = 550 nm. Is 132 nm (Re (λ) /λ=0.24), the retardation value Re (650) at the wavelength λ = 650 nm is 169 nm (Re (λ) /λ=0.26), and in a wide wavelength region. A phase difference of ¼ wavelength was given.

(Example 2) Manufacture of broadband quarter wave plate C-2 The long winding body A-2 and the long winding body B- obtained in Production Example 3 instead of the long winding body A-1 1 except that the long roll B-2 obtained in Production Example 5 was used instead of 1, and the roll was rolled by the roll-to-roll method in the same manner as in Example 1 to obtain a 3000 m long roll C-2. Got.
This wound body C-2 has a retardation value Re (450) at a wavelength λ = 450 nm of 113 nm (Re (λ) /λ=0.25), and a retardation value Re (550) at a wavelength λ = 550 nm. Is 143 nm (Re (λ) /λ=0.26), the retardation value Re (650) at the wavelength λ = 650 nm is 156 nm (Re (λ) /λ=0.24), and in a wide wavelength region. A phase difference of ¼ wavelength was given.

(Example 3) Production of broadband circularly polarizing element D-1 Broadband quarter-wave plate C-1 obtained in Example 1 and a long roll of polarizing plate (manufactured by Sanlitz, HLC2-5618S, thickness 180 μm and having an absorption axis in the longitudinal direction) are laminated by a roll-to-roll method so that the half-wave plate side of the broadband quarter-wave plate C-1 is in contact with the polarizing plate, A long wound body D-1 was obtained.
The long wound body D-1 of this circularly polarizing element was cut out to an appropriate size, and the broadband property and the viewing angle characteristic were evaluated. As a result of evaluation, all were good.

(Example 4) Manufacture of broadband circularly polarizing element D-2 A long winding of a circularly polarizing element in the same manner as in Example 3 except that the broadband quarter-wave plate C-2 obtained in Example 2 was used. State D-2 was obtained.
The long wound body D-2 of this circularly polarizing element was cut out to an appropriate size, and the broadband property and the viewing angle characteristic were evaluated. As a result of evaluation, all were good.

It is a figure which shows an example of the diagonal stretch apparatus. It is the conceptual diagram which showed extending | stretching angle (theta) of the unstretched laminated body (a) used for this invention. It is a figure which shows the elongate winding body (A) of the quarter wave plate used for this invention, and the elongate winding body (B) of a half wave plate. It is a figure which shows an example of the aspect of lamination | stacking with the long winding body (A) of the quarter wavelength plate by the roll to roll method, and the long winding body (B) of a half wavelength plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Unstretched film, 2-1 ... Film holding start point on the right side, 2-2 ... Film holding start point on the left side, 3-1 ... Trajectory of the film holding means on the right side, 3- 2 ... locus of film holding means on the left side, 4 ... tenter, 5-1 ... film holding end point on the right side, 5-2 ... film holding end point on the left side, 6 ... oblique stretching Film, 7-1 ... film feeding direction, 7-2 ... film width direction, 8 ... film stretching direction, 9-1 ... long-wave wound body of quarter wave plate (A), 9-2... Slow axis direction of the long winding body (A) of the quarter wave plate, 9-3... Long winding body of the quarter wave plate (A). The angle formed by the width direction and the slow axis (positive direction), 10-1... Half-wave plate long roll (B), 10-2. Long roll (B Slow axis direction, 10-3... Angle formed by the width direction of the long roll (B) of the half-wave plate and the slow axis (positive direction), 11... Feed roll, 12, 13 ... sandwiching rolls, 14 ... sandwiching rolls, A ... traveling direction of the unstretched laminate (a), B ... width direction of the unstretched laminate (a), C _1. .. Stretching direction when the stretching angle θ of the unstretched laminate (a) is 8 ° to 22 ° clockwise, C ₂ ... Stretching angle θ of the unstretched laminate (a) is clockwise − Stretching direction when it is 8 ° to −22 °, D: Positive direction with respect to the width direction of the unstretched laminate (a), E: With respect to the width direction of the unstretched laminate (a) Negative direction

Claims (5)

Intrinsic birefringence value having a glass transition temperature lower by 10 ° C. or more and 25 ° C. or less than the glass transition temperature of the resin having a negative intrinsic birefringence value on both surfaces of the layer (I) made of a resin having a negative intrinsic birefringence value Obtained by stretching an unstretched laminate (a) obtained by laminating a layer (II) made of a resin having a positive value in the stretching direction of −8 ° to −22 ° or 8 ° to 22 ° with respect to the width direction. A quarter-wave plate long roll (A) having a slow axis in the direction of 105 ° ± 7 ° or 75 ° ± 7 ° with respect to the width direction to be obtained;
15 ° ± 7 ° with respect to the width direction obtained by stretching the unstretched film (b) made of a transparent resin in the drawing direction of −8 ° to −22 ° or 8 ° to 22 ° with respect to the width direction, Or a long-wave body (B) of a half-wave plate having a slow axis in the direction of −15 ° ± 7 °,
A long roll (C) of a broadband quarter-wave plate, which is laminated so that the slow axes of each other intersect at 60 ° ± 7 °. The long wound body (C) of a broadband quarter-wave plate according to claim 1, wherein the unstretched film (b) is made of a polymer resin having an alicyclic structure. The long winding shape of the broadband circularly polarizing element formed by laminating the long winding body (C) of the broadband quarter-wave plate according to claim 1 or 2 on at least one surface of the long winding body of the polarizing element. Body (D). The long wound body (C) of the broadband quarter wave plate according to claim 1 or 2 or the long wound body (D) of the broadband circularly polarizing element according to claim 3 is cut out. A liquid crystal display device provided with at least one side of a liquid crystal cell. Intrinsic birefringence value having a glass transition temperature lower by 10 ° C. or more and 25 ° C. or less than the glass transition temperature of the resin having a negative intrinsic birefringence value on both surfaces of the layer (I) made of a resin having a negative intrinsic birefringence value An unstretched laminate (a) obtained by laminating a layer (II) made of a resin having a positive value is (Tg ₁ −10) ° C. with respect to the glass transition temperature Tg ₁ of the resin having a negative intrinsic birefringence value. The film is stretched in a stretching direction of -8 ° to -22 ° or 8 ° to 22 ° with respect to the width direction at a stretching temperature of ˜ (Tg ₁ +20) ° C. , and 105 ° ± 7 ° or 75 with respect to the width direction. Obtaining a long roll (A) of a quarter-wave plate having a slow axis in the direction of ° ± 7 °;
An unstretched film (b) made of a transparent resin is stretched in a stretching direction of −8 ° to −22 ° or 8 ° to 22 ° with respect to the width direction, and 15 ° ± 7 ° with respect to the width direction, or Obtaining a long roll (B) of a half-wave plate having a slow axis in the direction of −15 ° ± 7 °;
A broadband quarter-wave plate for performing the step of laminating the long winding body (A) and the long winding body (B) so that their slow axes intersect at 60 ° ± 7 ° The manufacturing method of the long winding body (C).