JP2002258045A - Optical retardation film, circularly/elliptically polarizing plate, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical retardation film scarcely having creases, surface waviness, scratches and/or optical unevenness in the width direction and scarcely causing breakdowns due to foreign matters in the manufacturing process and a circularly polarizing plate, an elliptically polarizing plate, a liquid crystal display device and a reflective liquid crystal display device using the optical retardation film. SOLUTION: The optical retardation film is obtained by solution-casting a polycarbonate resin which contains at least two kinds of repeating units and is derived from dihydroxy compounds, and subsequently by stretching the cast film to at least one axis direction. The optical retardation film is characterized by stretching the cast film with a 2-30 m/min stretching speed, or by solution casting the polycarbonate resin with a 1.2-3 m width, or by using the polycarbonate resin into which 1-50% waste films are redissolved, or by stretching the cast film using at least two sets of nip rolls arranged within 1-10 m distance or by making the cast and stretched film maintain an average value of an angle between a slow axis and the stretch axis in the plane within the range of ±5 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a retardation film and a circularly polarizing plate, an elliptically polarizing plate, a liquid crystal display, and a reflection type liquid crystal display using the same.

[0002]

2. Description of the Related Art A λ / 4 plate has many uses related to an antireflection film and a liquid crystal display device, and has already been actually used. However, even if it is referred to as a λ / 4 plate, most achieve λ / 4 at a specific wavelength. λ
If the wavelength region where / 4 can be achieved is narrow, there is a problem that the contrast of the displayed image is reduced. Further, in order to achieve a λ / 4 characteristic in a wide band, it is known to laminate two or more films as described in JP-A-10-68816. There is a problem that such a laminated film is expensive. As a method for solving this problem, λ / 4 using a polycarbonate copolymer is disclosed in WO
No. 00/26705. But this WO00 / 2
In the method described in the specification of No. 6705, wrinkles are liable to occur in the manufacturing process, medium thickening is liable to occur, scratches are liable to occur, optical unevenness is likely to occur in the width direction, and foreign matter failure is liable to occur. There is a need for improvement.

[0003]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a retardation film having a small medium thickness, a circularly polarizing plate, an elliptically polarizing plate, a liquid crystal display, and a reflection type liquid crystal display using the retardation film. Is to provide. A second object of the present invention is to provide a retardation film with less wrinkles and scratches, and a circularly polarizing plate, an elliptically polarizing plate, a liquid crystal display device, and a reflective liquid crystal display device using the retardation film. A third object of the present invention is to provide a retardation film in which foreign matter failure is unlikely to occur in a manufacturing process, and a circularly polarizing plate, an elliptically polarizing plate, a liquid crystal display device, and a reflective liquid crystal display device using the retardation film. It is in. A fourth object of the present invention is to provide a retardation film having a small thickness and optical unevenness in the width direction and a circularly polarizing plate using the retardation film,
An elliptically polarizing plate, a liquid crystal display device, and a reflection type liquid crystal display device are provided. A fifth object of the present invention is to provide a retardation film which has less wrinkles, medium thicknesses, scratches and optical unevenness in the width direction and is less likely to cause a foreign substance failure in a manufacturing process, a circularly polarizing plate using the retardation film, and an elliptically polarized light. An object of the present invention is to provide a plate, a liquid crystal display, and a reflection type liquid crystal display.

[0004]

According to the present invention, there are provided a retardation film, a circularly polarizing plate, an elliptically polarizing plate, a liquid crystal display device and a reflection type liquid crystal display device having the following constitutions, and the object of the present invention is achieved. Is done. 1. A polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound,
A retardation film formed by casting a solution at m / min and then stretching it in at least one axial direction. 2. Polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound, having a width of 1.
A retardation film obtained by casting a solution at a length of 2 m or more and 3 m or less and then stretching the film in at least one axial direction. 3. A polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound is solution-cast, and then stretched in at least one axis direction using at least two sets of nip rolls between 1 m and 10 m inclusive. A retardation film characterized by the following. 4. 4. The retardation film as described in 3 above, wherein the stretching is performed while passing through 2 to 50 rolls provided between the nip rolls. 5. The retardation film according to any one of the above items 1 to 4, wherein the film is cooled at a rate of -5 to -0.5C / sec after stretching. 6. The average value of the angle between the in-plane slow axis and the stretching axis in a thermoplastic film stretched at least uniaxially after solution-casting a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound. Is ± 5
°, a retardation film. 7. A polycarbonate film containing at least two kinds of repeating units derived from a dihydroxy compound is solution-cast, and then, in a thermoplastic film stretched at least uniaxially, the polycarbonate resin reduces film forming debris by 1 to 50.
A retardation film, characterized in that the content of the retardation film is not more than mass%. 8. A polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound contains 30 to 90 mol% of a repeating unit represented by the following general formula (III),
The retardation film according to any one of the above items 1 to 7, which contains 70 to 10 mol% of a repeating unit represented by the following general formula (IV), respectively (the total of both is 100 mol%). .

[0005]

Embedded image

[0006]

Embedded image

In the general formula (III), R ₂₄ and R ₂₅ each independently represent a hydrogen atom or a methyl group. In the general formula (IV), R ₂₆ and R ₂₇ each independently represent a hydrogen atom or a methyl group. Z represents any of the following skeletons.

[0008]

Embedded image

[0009] 9. Polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound, a repeating unit represented by the general formula (III) and a general formula (IV)
9. The retardation film as described in 8 above, which is a copolymer containing a repeating unit represented by the formula: 10. A polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound has a general formula
9. The retardation film as described in 8 above, which is a mixture of a polycarbonate containing a repeating unit represented by (III) and a polycarbonate containing a repeating unit represented by general formula (IV). 11. The limiting viscosity of a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound (measured in a dichloromethane solvent at 20 ° C.) is 2 dl / g.
And 1 to 4 dl / g or less.
11. The retardation film according to any one of 10). 12. Retardation values Re (450), Re (550), measured at 450 nm, 550 nm and 650 nm,
The above 1 wherein Re (650) satisfies the following formulas (1) and (2).
12. The retardation film according to any one of items 11 to 11. 0.6 <Re (450) / Re (550) <0.97 Formula (1) 1.01 <Re (650) / Re (550) <1.35 Formula (2) 13. The retardation film as described in 12 above, wherein Re (550) is from 120 to 300 nm. 14． Refractive index nx in the in-plane slow axis direction, refractive index ny in the direction perpendicular to the in-plane slow axis, and refractive index nz in the thickness direction
14. The retardation film according to any one of the above items 1 to 13, which satisfies the relationship of 1 ≦ (nx−nz) / (nx−ny) ≦ 2. 15. The retardation film according to any one of the above 1 to 14, wherein Re (550) is a λ / 4 plate having 120 to 160 nm or Re (550) is λ / 2 plate having 230 to 300 nm. 16. The angle between the λ / 4 plate and the λ / 2 plate described in 15 above is 5
A laminated retardation film, wherein the laminated retardation film is laminated so as to have an angle of 0 to 70 degrees. 17． 16. A circular or elliptically polarizing plate, wherein the λ / 4 plate or λ / 2 plate described in 15 above and a polarizing film are laminated. 18. 18. The circular or elliptically polarizing plate according to the above 17, wherein the polarizing film is a reflective polarizing film. 19. 19. A liquid crystal display device or a reflection type liquid crystal display device, wherein at least one of the retardation film described in 1 to 16 and the circular or elliptically polarizing plate described in 17 or 18 is used.

[0010]

Embodiments of the present invention will be described below in detail. The retardation film of the present invention is formed by using a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound, casting the solution, and then stretching it in a uniaxial direction. First, a polycarbonate resin containing at least two kinds of repeating units derived from the dihydroxy compound will be described.

In the present invention, the polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound is a copolymer type polycarbonate in which two or more kinds of repeating units composed of a dihydroxy compound are bonded. Examples thereof include those obtained by mixing two or more types of homopolymer type polycarbonates, and those obtained by mixing the above copolymer type and homopolymer type polycarbonates. If necessary, it suffices that the copolymer or the mixture contains at least two kinds of repeating units composed of a dihydroxy compound. Hereinafter, a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound,
It is simply referred to as “polycarbonate resin”.

The polycarbonate resin according to the present invention preferably contains a repeating unit represented by the above general formula (III) and a repeating unit represented by the above general formula (IV). Of course, it may be a copolymer type or a mixture type. Further, in a copolymer consisting of repeating units represented by the following formulas (V) to (IX), the proportion of the repeating unit (IX) is 40 to 7
5 mol% is preferable, and among them, (A) a copolymer comprising a repeating unit represented by the following formulas (VI) and (IX), wherein the proportion of (IX) is 30 to 70 mol%; (B) a copolymer comprising repeating units represented by the following formulas (VII) and (IX), wherein the proportion of the following formula (IX) is 30 to 70 mol%; and (c) the following formula (V) And a copolymer comprising a repeating unit represented by (VIII) and having a proportion of (VIII) of 40 to 75 mol% is more preferred.

[0013]

Embedded image

The most preferred polycarbonate resin is a unit derived from bisphenol A (BPA) (corresponding to the above formula (V)) and biscresol fluorene (BCF)
Is a polycarbonate resin comprising a unit derived from the above (corresponding to the above formula (IX)). As for the ratio of these units, the content of the above formula (IX) is preferably 55 to 75 mol%, more preferably 55 to 70 mol%. With these materials, ideal λ / 4 plates and λ / 2 plates described later can be obtained.

The intrinsic viscosity of the polycarbonate resin of the present invention, as measured at 20 ° C. in dichloromethane, is preferably more than 2 dl / g and 4 dl / g or less, more preferably more than 2 dl / g and 3.5 dl / g or less. And more preferably more than 2 dl / g and not more than 3 dl / g. The limiting viscosity of ordinary polycarbonate resin is 0.3 to 2.0 dl
In the present invention, it is preferable to use a polymer having a high molecular weight in the above range. The polycarbonate resin of the present invention has poor solubility, and it is necessary to dissolve the polycarbonate resin at a high concentration when trying to have a high viscosity such that no streaking occurs during casting. Failure to do so may cause malfunction. Therefore, it is preferable to use a polycarbonate resin having a high intrinsic viscosity (high molecular weight), which is easily viscous at a low concentration as in the present invention.

Next, essential or preferred conditions for producing the retardation film of the present invention using the above polycarbonate resin will be described. The retardation film of the present invention has 2 to
After casting the solution at a speed of 30 m / min, more preferably 3 to 25 m / min, and still more preferably 4 to 20 m / min, and then stretching at least uniaxially, a polycarbonate copolymer and / or a blend film is obtained. Become. As a result, it is possible to improve the medium thickness generated in the production of the retardation film. In the present invention, the term “medium thickness” refers to a phenomenon in which the central portion of the retardation film is stretched and the central portion bulges (looses) when the film is placed on a horizontal table. It is presumed that the medium tarmi can be improved for the following reasons. The polymer of the present invention is dissolved in a solvent, cast on a band or a drum, dried, and then peeled off to form a film. By casting at a speed in this range, the stress applied to the film at the time of peeling is made uniform. Can be. If the casting speed is lower than 2 m / min, the drying proceeds too much, and the difference between the residual solvent at both ends and the center of the film becomes large. On the other hand, when the casting speed is 3
When the speed exceeds 0 m / min, flakes from the band and drum due to poor drying are likely to occur.

Conventionally, polycarbonate resins for retardation films are generally run at a low speed of 1.5 m / min or less in order to maintain high flatness, but in the present invention, they are cast at a high speed as described above. It is a characteristic that In the present invention, in order to cast at high speed while maintaining flatness, a band,
It is a feature that this problem is overcome by using the heating from inside the drum in addition to the heating from the outside of the drum. At this time, it is preferable that the heating temperature from the inside be lower than the heating temperature from the outside.

In a preferred embodiment of the present invention, the polycarbonate resin is preferably 1.2 to 3 m in width, more preferably 1.5 to 2.7 m, and still more preferably 1.
After the solution is cast at 7 m to 2.5 m, it is stretched in at least one axial direction. By setting the width of the solution casting within the above range, optical unevenness in the width direction due to thickness unevenness can be reduced. This is for the following reason. That is, a neck-in in which the width becomes narrower with stretching occurs, but at this time, the stretching ratio is slightly larger at the end than at the center. As a result, optical unevenness is likely to occur. If the film forming width is narrow, the end portion that is stretched at such a high magnification is easily affected, and optical unevenness occurs throughout the width direction. By increasing the width, the influence of the edges was suppressed, and optical unevenness was eliminated.

The polycarbonate resin of the present invention is
m could be formed only in a narrow width of not more than m. This is because the polymer is difficult to peel off from the band or the drum, and if it is widened, it is stretched by the peeling tension, and the tension is unevenly applied, so that the optical unevenness tends to be rather large. In the present invention, this problem has been solved by coating the surface of the band or drum with a surfactant. The surfactant may be any of a cation, a nonion, and an anion, more preferably a nonionic surfactant, and still more preferably a long-chain aliphatic ester,
Specific examples include long-chain aliphatic phosphates. The coating amount of this surfactant is 1 mg / m ^2-
1 g / m ² is preferred.

Further, in a preferred embodiment of the present invention, in the stretching step for producing the retardation film of the present invention, at least two sets of preferably 1 m to 10 m, more preferably 2 m to 8 m, and still more preferably 3 m to 7 m. Stretching is performed using the nip rolls provided. In addition, after stretching, -5C / sec to -0.5C / sec, more preferably -4C / sec.
Sec to -0.7 ° C / sec, more preferably -3 ° C / sec to-
Cool at a rate of 1 ° C / sec. Also, between 2 and 50 nip rolls, preferably 3 to 40, more preferably
More preferably, 5 to 30 rolls (dense rolls) are provided, and stretching is preferably performed while passing through these rolls.

By these stretching operations, wrinkles and scratches can be prevented. This is for the following reason. The stretching causes a neck-in in the film, and the middle portion of the stretching becomes thinner than the stretching start portion. At this time, if the interval between the nip rolls is smaller than the above range, the film is rapidly stretched, and a sharp dimensional change in the width direction due to neck-in occurs. That is, since the width at the initial stage of stretching is large and the width at the central portion is small, wrinkles in the MD (longitudinal) direction are generated in an attempt to adjust the width. This becomes remarkable as the film width increases, and the stretching width is 1.3 m.
It becomes apparent as described above, and occurs more remarkably at 1.5 m or more. On the other hand, it is possible to cope with this problem by increasing the distance between the stretching nip rolls as in the present invention.

Further, the wrinkles are promoted in a cooling step after stretching. That is, the width of the film that has been thermally expanded with cooling becomes narrower. This change in width increases wrinkles. The increase in wrinkles is reduced by cooling at the above rate. Furthermore, in order to suppress the generation of scratches, it is preferable to install a dense roll between the above-mentioned stretching rolls. It is presumed that, when stretching is performed between two sets of nip rolls, tension concentrates on these two rolls, so that slip is likely to occur and scratches occur. For this reason, by installing a large number of dense rolls as in the present invention, since the tension changes for each roll, it is considered that scratches due to slipping hardly occur. In order to install such a dense roll, the long nip roll interval as described above is preferable.

In the retardation film of the present invention, the average value of the angle (axis deviation) between the in-plane slow axis and the stretching axis is within ± 5 °, more preferably ± 3 °, even more preferably ± 1. It is preferable that the angle be within 5 °. Thereby, optical unevenness in the width direction can be reduced. That is, in the stretching step, the stretching is easier to progress at the end than at the center, and when the slow axis is measured in the width direction, it is concavely curved. As described above, the displacement between the stretching axis and the slow axis occurs, and such optical non-uniformity causes optical unevenness in the width direction. Such optical unevenness becomes remarkable as the film width increases, and becomes apparent when the stretching width is 1.3 m or more, and becomes 1.5 times or more.
It occurs more remarkably at m or more. As a method of reducing such an axis deviation, it is preferable that the temperature of the end portion at the time of stretching is higher by 1 ° C. to 5 ° C. than the temperature of the central portion. More preferably, it can be achieved by increasing the central part of the diameter of at least one of the nip rolls used for stretching by 0.01% to 1%.

In a preferred embodiment of the present invention, as the polycarbonate resin, 1 to 50% by mass, more preferably 1 to 50% by mass of film-forming waste generated at the time of forming the retardation film (slit waste generated at the time of film-forming). Use a polycarbonate resin containing 5 to 40% by mass, more preferably 10 to 30% by mass. The film-forming waste may be melt-mixed with a new polycarbonate resin in advance, but without melt-mixing, it must be redissolved with a new polycarbonate resin to prepare a casting solution, which is then provided for the production of a retardation film. Is preferred. As a result, foreign matter failure can be reduced. Since the polycarbonate resin has low solubility, residue remaining after dissolution is apt to be generated, which causes a foreign substance failure. Since the slag is soft and easily deformed, it passes through the eyes with a normal filtration filter. On the other hand, the use of the film-forming waste dramatically suppresses the generation of slag, thereby suppressing the occurrence of foreign matter failure. This is presumed to be as follows. That is,
In the stage of low viscosity at the initial stage of dissolution, the solvent rapidly swells the outer periphery of the polycarbonate resin particles to form a high-viscosity layer. This hinders the diffusion of the solvent into the inside of the polycarbonate particles, and the inside tends to remain undissolved, and this becomes sloppy. On the other hand, the film-forming debris, which has been dissolved once, has high solubility, which dissolves and increases the viscosity of the entire solution. as a result,
Without forming the swelling layer as described above, the solvent slowly penetrates into the inside of the polycarbonate particles and dissolves into the inside, so that the generation of slag hardly occurs.

Hereinafter, the method for producing a retardation film of the present invention will be described along the production steps. [Preparation of Polycarbonate Copolymer] The high molecular weight polycarbonate copolymer preferably used in the present invention is prepared by the following method. That is, in the present invention, a polycarbonate resin obtained by polycondensation or melt polycondensation of a dihydroxy compound and phosgene by a known method is further subjected to solid phase polymerization to obtain a high molecular weight. The temperature of the solid-state polymerization is preferably 150 ° C to 250 ° C, more preferably 170 ° C.
To 250 ° C, more preferably 180 ° C to 250 ° C, and the polymerization time is preferably 1 hour to 50 hours, more preferably 2 hours to 30 hours, and still more preferably 3 hours to 1 hour.
5 hours. At this time, it is more preferable to carry out in an inert gas such as nitrogen or in a vacuum. Further, solid-phase polymerization in a solvent gas in which the polymer swells (for example, aromatic hydrocarbons such as benzene, toluene, and xylene, ethers such as THF, dioxane, and furan, and ketones such as MEK and pentanone). Is also preferred.

[Casting Film of Polycarbonate Resin Film] The thus obtained polycarbonate resin is dissolved in an organic solvent to prepare a high-viscosity solution (dope), which is cast and formed into a film. Preferred organic solvents are those containing methylene chloride and dioxolane as main components, and it is also preferable to add lower alcohols such as methanol, ethanol and butanol in an amount of 1 to 30% by mass. The amount of polycarbonate resin is 1 in these solutions.
Adjust so as to contain 0 to 40% by mass. More preferably, the amount of the polycarbonate resin is 10 to 30% by mass. In addition to the newly polymerized polymer, 1-50% by mass, more preferably 5-40% by mass, and even more preferably 10-30% by mass, in which both ends formed by the method described below are slit (film-forming waste). % Is preferably added.
It is preferable to add these film-forming wastes after cutting them into a size of about 1 cm square. After addition of the polymer, at room temperature (0-40
C.) at room temperature. The highly concentrated solution may be stirred under pressure and heating conditions.

From the prepared dope, it is produced by a solvent casting method. For the film forming method and equipment of the present invention, an ordinary solution casting film forming apparatus is used. That is, melting machine (pot)
The dope prepared from is temporarily stored in a storage tank, defoamed, filtered, and then sent to a pressurized die through a pressurized fixed-quantity gear pump that can deliver a high-precision fixed-quantity liquid. It is cast uniformly. It is preferable that the surface of the drum or the band is finished in a mirror state. The casting and drying methods in the solvent casting method are described in US Pat. No. 2,336,310.
No. 2367603, No. 2492078, No. 24
No. 92977, No. 2492978, No. 2607704
Nos. 2739069 and 2739070; British Patent Nos. 640731 and 736892; Japanese Patent Publication Nos. 45-4554 and 49-5614;
-176834, 60-203430, 62-
It is described in each publication of No. 115035. This casting may be a single layer or a multilayer. In the case of a multi-layer, a film may be produced while casting and laminating a dope from a plurality of casting ports provided at intervals in the traveling direction of the support, for example, as described in JP-A-61-158414. ,
JP-A-1-122419, JP-A-11-198285
The method described in the official gazettes such as Japanese Patent No. Alternatively, the film may be formed by casting from two casting ports, for example, Japanese Patent Publication No. 60-27562,
-94724, JP-A-61-947245, JP-A-61-104814, JP-A-61-158413,
It can be carried out by the methods described in JP-A-6-134933. Further, the polycarbonate solution of the present invention may contain other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing layer, and a mat layer).
Can be simultaneously cast.

At the peeling point where the support has made a complete round on the band or drum, the freshly dried dope film (also called web) is peeled from the support. At this time, the conveying speed of the band or the drum is set to 2 to 30 m / min, more preferably 3 to 25 m / min.
Min, more preferably 4 to 20 m / min. At this time, in addition to heating from outside the band and the drum, it is preferable to use heating from inside these together. Preferred heating temperature from the inside is 40 ° C to 80 ° C.
° C, more preferably 45 ° C to 70 ° C, even more preferably 45 ° C to 60 ° C. 80 ° C heating temperature from outside
To 180 ° C, more preferably 100 ° C to 170 ° C, even more preferably 120 ° C to 160 ° C. Further, it is preferable that the band or the drum is coated with a surfactant of 1 to 1 g / m ² , and a preferable surfactant is a long-chain fatty acid ester having 6 to 20 carbon atoms, more preferably 6 carbon atoms. And group 20 long-chain aliphatic phosphates. The both ends of the web thus peeled are sandwiched by clips, transported by a tenter while maintaining the width, and dried. Subsequently, transported by a group of rolls of a drying device, drying is completed, and the web is wound up to a predetermined length. Wind it up. The combination of the tenter and the roll group drying device varies depending on the purpose. In a solution casting film forming method used for a silver halide photographic material or a functional protective film for an electronic display, in addition to a solution casting film forming apparatus, an undercoat layer, an antistatic layer,
An antihalation layer, a protective layer and the like may be applied.

The width of the polycarbonate resin film thus obtained is preferably 1.2 m to 3 m, more preferably 1.5 m to 2.7 m, and still more preferably 1.7 m.
m to 2.5 m.

[Stretching of polycarbonate resin film]
A stretching process is performed on the cast film. Stretching may be performed in any of the vertical and horizontal directions, or a combination thereof. Of these, longitudinal or horizontal uniaxial stretching is preferred, and longitudinal uniaxial stretching is more preferred. The preferred stretching ratio is 1.2 to 2.5 times, more preferably 1.4 to
2.3 times, and more preferably 1.5 to 2.2 times.
Stretching may be performed in one step, or may be performed in multiple steps. In the case of performing in multiple stages, the product of each stretching ratio may be set within this range. The stretching speed is 50 to 1000% / min, more preferably 80 to 800% / min, and still more preferably 10 to 800% / min.
0-700% / min. Preferred stretching temperature is 180 ° C
To 250 ° C, more preferably 190 ° C to 240 ° C, even more preferably 195 ° C to 235 ° C. For such heating, a stretching zone may be housed in a casing and heated air may be supplied thereto, stretching may be performed by a nip roll installed therein, and heating may be performed using a heat roll having a heating device therein. It is also preferable to do so. Further, a radiant heat source such as a halogen heater may be used as the IR heater. These may be used alone or in combination. Further, in order to reduce the axial deviation, it is preferable that the temperature at the end is higher by 1 ° C. to 5 ° C., more preferably 2 ° C. to 4 ° C. than the temperature at the center. This can be achieved by adjusting the air-conditioning plate at the inlet of the supply air, using a heat roll provided with a heat source divided in the width direction, and using a radiant heat source divided in the width direction.

In the present invention, stretching is performed by changing the peripheral speed of two or more sets of nip rolls, and the interval between the nip rolls is preferably 1 to 10 m, more preferably 2 to 8 m, and still more preferably 3 to 7 m. It is also preferable to stretch while passing 2 to 50, more preferably 3 to 40, and still more preferably 5 to 30 rolls (dense rolls) between the nip rolls. Furthermore, in order to reduce the axial deviation, the central part of the diameter of at least one of the nip rolls is set to 0.01 to 1%, more preferably 0.05 to 0.7%,
More preferably, the thickness is increased by 0.08 to 0.6%. After stretching, a rate of -5 ° C / sec to -0.5 ° C / sec, more preferably -4 ° C / sec to -0.7 ° C / sec, and still more preferably -3 ° C / sec to -1 ° C / sec. Wrinkles,
It is preferable from the viewpoint of preventing scratches.

The present invention provides a retardation film comprising a polycarbonate resin film, wherein the average value of the angle (axis deviation) between the in-plane slow axis and the stretching axis is within ± 5 °, more preferably within ± 3 °, It is more preferable that the angle be within ± 1.5 °. Thereby, optical unevenness in the width direction can be reduced. That is, in the stretching step, the stretching is easier to progress at the end than at the center, and when the slow axis is measured in the width direction, it is concavely curved. In this way, the displacement between the stretching axis and the slow axis occurs,
Such optical non-uniformity causes optical unevenness in the width direction. Such optical unevenness becomes remarkable as the film width increases, and becomes more apparent when the stretching width is 1.2 m or more, and more remarkably occurs when the stretching width is 1.5 m or more. As a method of reducing such an axis shift, the temperature at the end is set to be 1 ° C.
It is preferable to increase the temperature by ℃. More preferably, the central part of the diameter of at least one of the nip rolls is 0.01 to
This can be achieved by increasing the thickness by 1%.

The thus obtained film 450
550 nm, 650 nm, Re (450), Re (550), Re (65)
0) preferably satisfies the following formulas (1) and (2): 0.6 <Re (450) / Re (550) <0.97 Formula (1) 1.01 <Re (650) / Re (550) <1.35 Expression (2) More preferably, the following expressions (3) and (4) are satisfied: 0.65 <Re (450) / Re (550) <0.92 ... Formula (3) 1.04 <Re (650) / Re (550) <1.30 Formula (4) More preferably, the following formulas (5) and (6) should be satisfied. 0.70 <Re (450) / Re (550) <0.87 Equation (5) 1.07 <Re (650) / Re (550) <1.25 Equation (6)

Re (550) is from 120 to 300.
nm is preferred. When used as a λ / 4 plate, the thickness is preferably 120 to 160 nm, more preferably 1 to 160 nm.
25 to 155 nm, more preferably 130 to 150 n
m. 250 to 3 when used as a λ / 2 plate
00 nm is preferred, and more preferably 255-295 n
m, more preferably 260 to 290 nm.

The retardation film of the present invention has the following formula (A)
DR0 (λ), DR20 (λ),
DR40 (λ) is measured at 450nm and 750n
m, preferably | DR20 (λ) −DR0 (λ) | ≦ 0.02 | DR40 (λ) −DR0 (λ) | ≦ 0.02, more preferably | DR20 (λ) −DR0 (λ) | ≦ 0.015 | DR40 (λ) −DR0 (λ) | ≦ 0.015 More preferably | DR20 (λ) −DR0 (λ) | ≦ 0.01 | DR40 (λ) −DR0 (λ) | ≦ 0 .01 is desirably satisfied. Formula (A): DR0 (λ) = Re (λ) / Re (550) Formula (B): DR20 (λ) = Re20 (λ) / Re20 (550) Formula (C): DR40 (λ) = Re40 ( λ) / Re40 (550) In the above formula, λ is the measurement wavelength, Re (λ) is the retardation value measured in the normal direction of the film surface, Re
20 (λ) is the retardation value measured at an angle of 20 ° from the normal direction of the film surface, and Re40 (λ) is
It shows the retardation value measured at an angle of 40 ° from the normal direction of the film surface.

Further, the refractive index nx in the direction of the slow axis in the plane of the retardation film of the present invention, the refractive index ny in the direction perpendicular to the slow axis in the plane, and the refractive index nz in the thickness direction are preferable.
1 ≦ (nx−nz) / (nx−ny) ≦ 2, more preferably 1.2 ≦ (nx−nz) / (nx−ny) ≦
1.9, more preferably 1.3 ≦ (nx−nz) /
It is desirable to satisfy (nx-ny) ≦ 1.8. Further, the haze value of the retardation film of the present invention is 3% or less,
The total light transmittance is preferably 85% or more. The thickness is 50-50
0 μm is preferable, and more preferably 60 to 300 μm,
More preferably, it is 70 to 200 μm.

[Circularly Polarized Plate / Elliptically Polarized Plate] The retardation film of the present invention can be used as a λ / 4 or λ / 2 plate. In addition, the retardation film of the present invention can be made into a circularly polarizing plate or an elliptically polarizing plate by bonding to a polarizing plate via an adhesive layer and an adhesive layer, or by coating some material on the retardation film to improve wet heat durability. It may be improved or the solvent resistance may be improved. In the retardation film of the present invention, an ideal λ / 4 plate or λ / 2 plate having a smaller birefringence as the wavelength becomes shorter can be obtained by one polymer oriented film. The retardation films of the present invention are laminated together, or the retardation films of the present invention and other optical films (phase difference films,
(A polarizing plate, an optical compensator, etc.), and a retardation film that is more widely suited to various uses, such as producing ideal λ / 4 plates and λ / 2 plates in a wider wavelength range. Alternatively, an optical film can be obtained.

When linearly polarized light is incident on the above-mentioned laminated retardation film, almost complete circularly polarized light is obtained at any wavelength within the measurement wavelength range of 400 to 700 mm, preferably 400 to 780 mm. When polarized light is incident on the laminated retardation film, the measured wavelength is 400 to 700 nm.
, Almost perfect linearly polarized light can be obtained at any wavelength. Such a laminated retardation film includes two retardation films of the present invention, namely, a half-wave plate and a 1/2 wavelength plate.
This is achieved by laminating four-wavelength plates, preferably by laminating them so that the angle between their optical axes is in the range of 50 to 70 °. If the bonding angle is out of this range, good characteristics cannot be obtained.

The circularly polarizing plate is an angle formed by a slow axis in the plane of the λ / 4 plate or λ / 2 plate and a polarizing axis of the polarizing plate. Is substantially 45 °
And glue them together. A polarizing plate refers to a polarizing plate in which a polarizing film is sandwiched between transparent protective films. Substantially 45 ° means a range of 40 to 50 °, preferably 43 to 47 °, and more preferably 44 to 46 °.

The elliptically polarizing plate is formed such that the angle between the slow axis in the plane of the λ / 4 or λ / 2 plate and the polarizing axis of the polarizing plate is substantially the same as the λ / 4 or λ / 2 plate. It is stuck so that it is 75 ° or 15 °. A polarizing plate refers to a polarizing plate in which a polarizing film is sandwiched between transparent protective films. Substantially 75 ° is in the range of 70 ° to 80 °, preferably 73 ° to 78 °, and more preferably 74 ° to 76 °. Substantially 15 ° is 1
1 to 19 °, preferably 13 to 17 °, more preferably 14 to 16 °.

The polarizing film includes an iodine-based polarizing film, a dye-based polarizing film using a dichroic dye, and a polyene-based polarizing film. The iodine-based polarizing film and the dye-based polarizing film are generally manufactured using a polyvinyl alcohol-based film. The polarization axis of the polarizing film corresponds to a direction perpendicular to the stretching direction of the film. In a circularly polarizing plate or an elliptically polarizing plate, it is preferable to provide a transparent protective film on the surface of the polarizing film opposite to the surface on which the λ / 4 or λ / 2 plate is laminated.

[Reflective Liquid Crystal Display Element] The reflective liquid crystal display device comprises, in order from the bottom, a lower substrate, a reflective electrode, a lower alignment film, a liquid crystal layer, an upper alignment film, a transparent electrode, an upper substrate, a λ / 4 plate, and It consists of a polarizing film. The lower substrate and the reflection electrode form a reflection plate.
The lower alignment film to the upper alignment film constitute a liquid crystal cell. The λ / 4 plate can be arranged at any position between the reflection plate and the polarizing film. In the case of color display, a color filter layer is further provided. The color filter layer is preferably provided between the reflective electrode and the lower alignment film or between the upper alignment film and the transparent electrode. A reflection plate may be separately attached using a transparent electrode instead of the reflection electrode. As a reflector used in combination with a transparent electrode, a metal plate is preferable. If the surface of the reflector is smooth, only the specular reflection component is reflected, and the viewing angle may be narrowed. Therefore, it is preferable to introduce an uneven structure (described in Japanese Patent No. 275620) on the surface of the reflection plate. When the surface of the reflector is flat (instead of introducing an uneven structure on the surface), a light diffusion film may be attached to one side (cell side or outside) of the polarizing film.

The liquid crystal cell is a TN (twisted nematic)
Type, STN (Supper Twisted Nematic) type or HAN
(Hybrid Aligned Nematic) type is preferred.
The twist angle of the TN type liquid crystal cell is preferably 40 to 100 °, more preferably 50 to 90 °, and most preferably 60 to 80 °. The value of the product (Δnd) of the refractive index anisotropy (Δn) of the liquid crystal layer and the thickness (d) of the liquid crystal layer is preferably 0.1 to 0.5 μm, and 0.2 to 0.4 μm. It is more preferred that there be. The twist angle of the STN type liquid crystal cell is 180 to 360.
こ と が is preferable, and 220 to 270 ° is more preferable. The value of the product (Δnd) of the refractive index anisotropy (Δn) of the liquid crystal layer and the thickness (d) of the liquid crystal layer is 0.3 to
1.2 μm, preferably 0.5 to 1.0 μm
Is more preferable. In the HAN type liquid crystal cell, it is preferable that the liquid crystal is substantially vertically aligned on one substrate and the pretilt angle on the other substrate is 0 to 45 °. The value of the product (Δnd) of the refractive index anisotropy (Δn) of the liquid crystal layer and the thickness (d) of the liquid crystal layer is preferably 0.1 to 1.0 μm, and 0.3 to 0.8 μm. It is more preferred that there be. The substrate on which the liquid crystal is vertically aligned may be a substrate on the reflection plate side or a substrate on the transparent electrode side.

The reflection type liquid crystal display device can be used in a normally white mode in which the display is bright when the applied voltage is low and a dark display when the applied voltage is high, or in a normally black mode in which the display is dark when the applied voltage is low and bright when the applied voltage is high. be able to. Normally white mode is preferred.

[Guest-Host Reflective Liquid Crystal Display Element] The guest-host reflective liquid crystal display element comprises a lower substrate, an organic interlayer insulating film, a cholesteric color reflector, a λ / 4 plate, a lower transparent electrode, a lower alignment film, a liquid crystal layer, It has a structure in which an upper alignment film, an upper transparent electrode, an upper substrate, and an antireflection layer are stacked in this order. The lower substrate and the upper substrate are made of a glass plate or a plastic film. A TFT is mounted between the lower substrate and the organic interlayer insulating film. The λ / 4 plate may also function as a light diffusion plate. The liquid crystal layer is composed of a mixture of a liquid crystal and a dichroic dye. The liquid crystal layer is obtained by injecting a mixture of liquid crystal and a dichroic dye into a cell gap formed by the spacer. Instead of providing a light diffuser,
By providing irregularities on the surface of the metal reflection plate, a light diffusion function may be imparted to the metal reflection plate. A black matrix is attached between the upper transparent electrode and the upper substrate.
The antireflection layer preferably has an antiglare function in addition to the antireflection function. The λ / 4 plate according to the present invention can be used as a λ / 4 plate of a guest-host reflection type liquid crystal display device. Japanese Patent Application Laid-Open Nos. 6-222350 and 8-361 describe a guest-host reflection type liquid crystal display device having a λ / 4 plate.
No. 74, No. 10-268300, No. 10-29217
No. 5, No. 10-293301, No. 10-319776
Nos. 10-319442 and 10-325595
And JP-A-10-333138 and JP-A-11-38410.

The measurement method used in the present invention will be described below. Measurement of Retardation and Refractive Index For the produced cellulose acetate film (retardation plate), the retardation values at wavelengths of 450 nm, 550 nm and 650 nm were measured using an ellipsometer (M-150, manufactured by JASCO Corporation). .
In addition, the refractive index nx in the in-plane slow axis direction at a wavelength of 550 nm and the refractive index in the direction perpendicular to the in-plane slow axis were measured from the refractive index measurement by Abbe refractometer and the measurement of the angle dependence of the retardation. ny and the refractive index nz in the thickness direction were obtained, and the value of NZ = (nx−nz) / (nx−ny) was calculated. Measurement of misalignment The angle between the direction of the slow axis of the cellulose acetate film and the stretching direction is determined by an automatic birefringence meter (KOBRA-21AD).
H, Oji Scientific Instruments). Each measurement is performed at any 10 points in the film, the average direction is determined,
The difference between this and the stretching axis was determined. Intrinsic viscosity In a dichloromethane solvent using an Ubbelohde viscosity tube, 2
Determined at 0 ° C.

[0047]

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to the examples.

[1. Preparation of Retardation Film] (1) Polymerization of Polycarbonate Copolymer An aqueous sodium hydroxide solution and ion-exchanged water are charged into a reaction tank equipped with a stirrer, a thermometer, and a reflux condenser, and the following structural formulas (A) and ( The dihydroxy compounds represented by F) and (G) were dissolved at the molar ratios shown in Table 1, and a small amount of hydrosulfite was added. Next, add methylene chloride to this,
At 20 ° C., phosgene was bubbled in for about 60 minutes. Further p-
After adding tert-butylphenol and emulsifying, triethylamine was added and the mixture was stirred at 30 ° C. for 3 hours to terminate the reaction. After completion of the reaction, the organic layer was separated and methylene chloride was evaporated to obtain a polycarbonate copolymer. These two
Solid phase polymerization was performed at 30 ° C. for the time shown in Table 1 under an atmosphere. In addition, the vapor concentration in the case of carrying out in a solvent vapor atmosphere was 3 vol.

[0049]

Embedded image

(2) Film formation The polycarbonate copolymer shown in Table 1 and film-forming debris were gradually added to a dichloromethane solvent with good stirring, and allowed to stand at room temperature (25 ° C.) for 3 hours to swell. The obtained swollen mixture was dissolved in a mixing tank having a reflux condenser with stirring at 50 ° C. to prepare a dope having a polymer concentration of 15%. This dope was filtered with a filter paper (No.
244) and filtered through a filter cloth made of flannel, and the solution was fed to a pressure die by a fixed-quantity gear pump, and cast at a casting speed shown in Table 1 using a band casting machine having an effective length of 6 m. The temperature outside and inside the band was set to the temperature shown in Table 1, and the surface was further coated with a lauryl phosphate as a surfactant in an amount shown in Table 1. When the volatile content in the film became 50% by mass, the film was peeled off from the band,
3 minutes at 130 ° C., 5 minutes at 130 ° C., and 5 minutes at 160 ° C., shrinking freely without fixing the film, and drying step by step.
The remaining solvent was evaporated to less than 1%. Thereafter, these are trimmed by 15 cm at both ends, and the height is 50 μm at both ends.
Knurling (thickness processing) with a width of 1 cm was performed to obtain an unstretched film having a width shown in Table 1 and a length of 3000 m. Here, the trimmed film waste is pulverized and reused as the above film-forming waste.

[0051]

[Table 1]

(3) Stretching An unstretched film was unwound from a delivery placed outside the thermostat and fed into a thermostat set at the temperature shown in Table 1. A stainless steel roll coated with hard chrome having a diameter of 15 cm and a rubber-coated nip roll having a diameter of 5 cm were placed in the thermostat at a distance between the roll centers shown in Table 1. At this time, the center of both nip rolls was made wider from both ends by the amount shown in Table 1 (roll diameter ratio). Further, by using a divided heater, the stretching temperature was increased from the both ends at the center by the amount shown in Table 1. Further, a dense roll coated with hard chrome having a diameter of 10 cm was passed between the nip rolls by the number shown in Table 1. The film was stretched at the magnification shown in Table 1 and then cooled at the speed shown in Table 1 to obtain a film having the thickness shown in Table 1.

(4) Evaluation The stretch fill was evaluated and the results are shown in Table 2. Retardation (Re), (nx-nz) / (nx-ny) (Table 1)
And Nz), and the axis deviation was determined according to the above method.
The height of the wrinkles was sampled at a length of 1 m in the longitudinal direction (MD) with the entire width, placed on a horizontal and smooth table, and all the gaps between the film and the table were measured with calipers, and the maximum value was described. .

The amount of medium tarmi was measured by the following method. Sampling is performed at a length of 5 m in the longitudinal direction (MD) over the entire width. The film parallel to the rolls is placed on a pair of rolls with a diameter of 10 cm placed in parallel at 4 m intervals. One end in the width direction of the film is fixed to a roll over the entire width with an adhesive tape. The other end in the width direction is fixed to a rigid rod having a diameter of 1 cm with tape, and this is passed over the other roll. Hang a 1kg weight on a rigid rod of, and tension the film. A rigid plate is passed between a pair of rolls, and the gap between the plate and the film is measured over the entire width, and the maximum gap is defined as the amount of medium thickness. The gap increases).

For scratches, the MD is sampled by a length of 1 m over the entire width, irradiated with a point light source (tungsten lamp), and a bright spot is visually measured. This is divided by the measured area (m ² ) and normalized. Optical unevenness is obtained by sampling 5 points uniformly in the MD direction, 10 points equally in the width direction, and 5 cm diagonally sampled from a 1 m long MD sampled across the entire width, and placed between orthogonally arranged polarizing plates. Then, the total light transmittance is measured. The absolute value of the difference between the maximum transmittance and the minimum transmittance at this time was defined as optical unevenness. The foreign matter was sampled at 5 points uniformly in the MD direction, 10 points evenly in the width direction, and 5 cm diagonally sampled from a 1 m long sample in the MD over the entire width. The number of foreign substances confirmed in the above was counted, and this was standardized and determined by the observation area (cm ² ).

[0056]

[Table 2]

[2. Production of Circular Polarizing Plate] Transparent protective film, polarizing film and Examples 1, 2-1, 3-1 4-1 and 4-2,
4-3, 4-5 retardation film to retardation plate (λ / 4)
It was cut to a diagonal of 15 inches in order to use it, and laminated in this order to obtain a circularly polarizing plate. The angle between the slow axis of the retardation plate and the polarization axis of the polarizing film was adjusted to 45 °. This is mounted on a reflective liquid crystal panel, and a measuring device (EZ Contrast 160D, EL
(Manufactured by DIM Co., Ltd.). In addition, with respect to all the levels, sampling was performed from the end of the raw material where non-uniformity is most likely to occur. Regardless of where in the screen, the contrast ratio from the front is 26, and the viewing angle at which the contrast ratio is 3 is 130 ° or more in the vertical direction and 11 ° in the left and right directions in the embodiment.
0 ° or more. On the other hand, it was 70 ° or less in the comparative example. Particularly, near the end of the raw material, the viewing angle was significantly reduced to 60 ° or less.

[3. Preparation of elliptically polarizing plate] Examples 1, 2-
1, 3-1, 4-1, 4-2, 4-3, and 4-5 are used as λ / 4 plates, and the retardation films of Examples 5 and 6 are used as λ / 2 plates. Combining these,
An elliptically polarizing plate was prepared by laminating a polarizing plate, a λ / 4 plate, a λ / 2 plate, and a reflecting plate in this order. The lamination was performed so that the λ / 4 slow axis angle was 15 degrees and the λ / 2 slow axis angle was 75 degrees with respect to the polarization axis. The sampling was performed at a diagonal size of 15 inches from the end of the raw material. 550 of this elliptically polarizing plate
As a result of measuring the reflectance in nm, good results were obtained at 0.01% or less over the entire screen. In addition, no coloring was observed, and the result was good. On the other hand, the retardation films of Comparative Example 1 and Example 6 were used as a λ / 4 plate and a λ / 2 plate, and as a result of measurement in the same manner as described above, the reflectance exceeded 0.1%. In particular, near the edge of the raw material, the increase in reflectance significantly exceeded 0.2%.

[4. Production of reflective liquid crystal display element] ITO
A glass substrate provided with a transparent electrode and a glass substrate provided with an aluminum reflective electrode having fine irregularities were prepared. A polyimide alignment film (SE-7992, manufactured by Nissan Chemical Industries, Ltd.) was formed on each of the two glass substrates on the electrode side, and rubbing treatment was performed. Two substrates were stacked via a 2.5 μm spacer so that the alignment films faced each other. The directions of the substrates were adjusted so that the rubbing directions of the two alignment films intersect at an angle of 117 °. Liquid crystal (MLC-6252, manufactured by Merck) is injected into the gap between the substrates,
A liquid crystal layer was formed. Thus, the twist angle is 63
A TN type liquid crystal cell having ゜ and Δnd values of 198 nm was produced. The circularly polarizing plate produced by the above method was attached to the side of the glass substrate provided with the ITO transparent electrode via an adhesive. On top of that, a protective film whose surface was subjected to AR treatment was further adhered. These were also sampled from the end of the raw material in the same manner as described above. A 1 kHz rectangular wave voltage was applied to the manufactured reflective liquid crystal display device. Visual evaluation was performed with a white display of 1.5 V and a black display of 4.5 V. In this example, it was confirmed that the white display and the black display had no color and neutral gray was displayed. . Next, when the contrast ratio of the reflection luminance was measured using a measuring device (EZcontrast160D, manufactured by Eldim), the contrast ratio from the front was 23 or more and the viewing angle at which the contrast ratio was 3 was 3 All up and down 120 ゜
It was 120 ° or more on the left and right. On the other hand, it was 60 ° or less in the comparative example.

[5. Production of Guest Host Reflective Liquid Crystal Display Element] On a glass substrate provided with an ITO transparent electrode,
A solution of a polymer for forming a vertical alignment film (LQ-1800, manufactured by Hitachi Chemical DuPont Microsystems) was applied, dried, and then rubbed. On a glass substrate on which aluminum was deposited as a reflector, the λ /
Four plates (retardation plates) were attached with an adhesive. These were all sampled from the end of the web. On a λ / 4 plate, an SIO layer is provided by sputtering, and
A TO transparent electrode was provided. A solution of a polymer for forming a vertical alignment film (LQ-1800, manufactured by Hitachi Chemical DuPont Microsystems) is applied on the transparent electrode, dried, and then rubbed in a direction of 45 ° from the slow axis direction of the λ / 4 plate. Was done. Two glass substrates were stacked via a 7.6 μm spacer such that the alignment films faced each other. The orientation of the substrate was adjusted so that the rubbing direction of the alignment film was antiparallel. In a gap between the substrates, 2.0% by mass of a dichroic dye (NKX-1366, manufactured by Nippon Kogaku Dyeing Co., Ltd.) and a liquid crystal (ZLI-280)
6, 98.0% by mass of Merck Co., Ltd.) was injected by a vacuum injection method to form a liquid crystal layer. 1 kHz between the ITO electrodes of the fabricated guest-host reflection type liquid crystal display device
Was applied. The present invention provides a white display 1
V and black display at 10 V have a transmittance of 65% or more and 6 respectively.
%, The transmittance ratio between white display and black display (contrast ratio) is 11: 1 or more.
All were good at 20 ° or more. The transmittance was measured while increasing and decreasing the voltage, but no hysteresis was observed in the transmittance-voltage curve.

[0061]

According to the present invention, there is provided a retardation film which has less wrinkles, medium bulges, scratches and / or optical unevenness in the width direction, and is less likely to cause a foreign substance failure in a manufacturing process. Furthermore, a circularly polarizing plate using this retardation film,
An elliptically polarizing plate, a liquid crystal display, and a reflective liquid crystal display are provided.

Claims (19)

[The claims] 1. A resin obtained by casting a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound at a rate of 2 to 30 m / min and then stretching in at least one axial direction. Characteristic retardation film. 2. A retardation, wherein a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound is cast in a solution having a width of 1.2 m or more and 3 m or less, and then stretched in at least one axis direction. the film. 3. A solution obtained by casting a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound, and then using at least two sets of nip rolls between 1 m and 10 m inclusive.
A retardation film stretched in the axial direction. 4. The stretching device is provided between two nip rolls.
The retardation film according to claim 3, wherein the retardation is performed while passing through 50 rolls. 5. The retardation film according to claim 1, wherein the film is cooled at a rate of -5 to -0.5 ° C./sec after stretching. 6. An angle between an in-plane slow axis and a stretching axis in a thermoplastic film stretched at least uniaxially after solution-casting a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound. A retardation film having an average value of ± 5 ° or less. 7. A thermoplastic film stretched at least uniaxially after solution-casting a polycarbonate resin containing at least two types of repeating units derived from a dihydroxy compound, wherein the polycarbonate resin reduces film forming debris by 1 to 50 mass%. % Or less. 8. A polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound, has a repeating unit represented by the following general formula (III) of from 30 to 30:
90 mol%, 70 to 10 mol% of a repeating unit represented by the following general formula (IV), respectively (the total of both is 100
Mol%). The retardation film according to any one of claims 1 to 7, wherein Embedded image Embedded image In the general formula (III), R ₂₄ and R ₂₅ are each independently:
Represents a hydrogen atom or a methyl group. In the general formula (IV), R ₂₆
And R ₂₇ each independently represent a hydrogen atom or a methyl group. Z represents any of the following skeletons. Embedded image 9. A polycarbonate resin comprising at least two kinds of repeating units derived from a dihydroxy compound, wherein the repeating unit represented by the general formula (III) and the repeating unit represented by the general formula (IV)
The retardation film according to claim 8, which is a copolymer containing a repeating unit represented by the formula: 10. A polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound, contains a polycarbonate containing a repeating unit represented by the general formula (III) and a repeating unit represented by the general formula (IV) The retardation film according to claim 8, wherein the retardation film is a mixture with polycarbonate. 11. The limiting viscosity of a polycarbonate resin containing at least two kinds of repeating units derived from a dihydroxy compound (measured in a dichloromethane solvent at 20 ° C.) is 2
The retardation film according to any one of claims 1 to 10, wherein the retardation film is more than dl / g and not more than 4 dl / g. 12. The retardation values Re (450) and Re (5) measured at 450 nm, 550 nm and 650 nm.
50), The retardation film according to any one of claims 1 to 11, wherein Re (650) satisfies the following formulas (1) and (2). 0.6 <Re (450) / Re (550) <0.97 Formula (1) 1.01 <Re (650) / Re (550) <1.35 Formula (2) 13. The retardation film according to claim 12, wherein Re (550) is from 120 to 300 nm. 14. The refractive index nx in the in-plane slow axis direction, the refractive index ny in the direction perpendicular to the slow axis in the plane, and the refractive index nz in the thickness direction are 1 ≦ (nx−nz) / (nx The retardation film according to any one of claims 1 to 13, which satisfies a relationship of -ny) ≦ 2. 15. The retardation film according to claim 1, which is a λ / 4 plate having Re (550) of 120 to 160 nm or a λ / 2 plate having Re (550) of 230 to 300 nm. 16. A laminated retardation film which is laminated so that the angle between the λ / 4 plate and the λ / 2 plate according to claim 15 is 50 to 70 °. 17. The λ / 4 plate or λ / plate according to claim 15,
A circular or elliptically polarizing plate, wherein two plates and a polarizing film are laminated. 18. The circular or elliptically polarizing plate according to claim 17, wherein the polarizing film is a reflective polarizing film. 19. A liquid crystal display device or a reflection type wherein at least one of the retardation film according to claim 1 and the circular or elliptically polarizing plate according to claim 17 or 18 is used. Liquid crystal display.