WO2014017725A1

WO2014017725A1 - Film-forming roll and method for manufacturing optical film using same

Info

Publication number: WO2014017725A1
Application number: PCT/KR2013/002677
Authority: WO
Inventors: 최종규; 조진희; 유소희; 이승규; 김란; 구준모; 박종선; 은종혁; 정오용
Original assignee: 제일모직 주식회사
Priority date: 2012-07-25
Filing date: 2013-04-01
Publication date: 2014-01-30
Also published as: KR20140014738A

Abstract

The present invention relates to a film-forming roll and to a method for manufacturing an optical film using same. The film-forming roll includes: a rotatable cylindrical inner member; a surface member formed apart from the outer circumferential edge of the cylindrical inner member; and a liquid layer filled between the cylindrical inner member and the surface member.

Description

Film forming rolls and optical film manufacturing method using the same

The present invention relates to a film forming roll and an optical film manufacturing method using the same. More specifically, the present invention relates to a film forming roll capable of expressing the inclined characteristics of the refractive index main axis in the film thickness direction and an optical film manufacturing method using the same.

Liquid crystal displays (LCDs) are one of the most widely used flat panel displays. In general, a liquid crystal display has a structure in which a liquid crystal layer is enclosed between a thin film transistor (TFT) array substrate and a color filter substrate. When an electric field is applied to the electrodes on the array substrate and the color filter substrate, the arrangement of the liquid crystal molecules of the liquid crystal layer enclosed therebetween changes, thereby displaying an image. On the other hand, a polarizing film (polarizing plate) is provided outside the array substrate and the color filter substrate. The polarizing film may control polarization by selectively transmitting light in a specific direction among light incident from the backlight and light passing through the liquid crystal layer. The polarizing plate generally includes a polarizer, a protective layer, and a compensation film capable of polarizing light in a specific direction.

Due to the refractive anisotropy of the liquid crystal, the liquid crystal display has a fundamental problem of a viewing angle. As a kind of optical viewing angle compensation film, the viewing angle of TN (Twist Nematic) type has a limited problem of 120 degrees in the horizontal direction and 90 degrees in the vertical direction.

In order to solve this problem, a wide viewing angle film for compensating the viewing angle is used. The wide viewing angle compensation film compensates for the phase delay to compensate for the wide viewing angle, and has various compensation functions such as improving contrast ratio, gray scale inversion, and color change.

In JP 2006-267241, after rubbing treatment is performed on the lower transparent film fabric surface, the coating liquid is oriented on the surface above the liquid crystal glass transition temperature, and the alignment is fixed to form an optically anisotropic layer. After that, a technique for producing a product by winding a laminating agent is disclosed.

JP H6-6-222213 discloses a technique for producing a film having a compensation function by forming an optical axis by varying the peripheral speed difference between rolls when a solidified film fabric prepared by extrusion processing polycarbonate is formed.

JP 2003-025414 describes the construction of the processing rolls, the first roll applying the metal plated roll on the elastic rubber roll surface, and the second roll applying the normal metal roll to incline the optical axis under the conditions above the glass transition temperature of the raw material resin. Disclosed is a technique to make. This method is advantageous in realizing the inclination angle by widening the contact area between the rolls, but because of the surface roughness, a transparent product cannot be made.

JP 2010-058495 discloses a technique for tilting an optical axis by giving a circumferential speed difference between rolls when an extrusion melt is introduced between a rubber coated metal roll and a general metal roll. At this time, the pressure between each applied roll can be variously adjusted, and if the pressure between the rolls is increased, the inclined structure can be increased and a film with high optical uniformity can be produced.

JP 2011-059471 discloses a technique of obtaining an inclined angle as much as possible by giving a main speed difference between metal rolls in the process of co-extrusion and feeding between metal rolls, and then peeling the surface layer with poor appearance and obtaining only the protected layer in the middle.

One object of the present invention is to provide a film forming roll and an optical film manufacturing method using the same that can express the inclination characteristics of the refractive index main axis in the film thickness direction.

Another object of the present invention is to provide a film-forming roll and an optical film manufacturing method using the same in which the surface is not inclined orientation occurs in the single film during the film forming, the inside can express the inclined orientation.

Still another object of the present invention is to provide a film forming roll capable of expressing uniform physical properties according to film width during film formation and an optical film manufacturing method using the same.

Still another object of the present invention is to provide a film forming roll and an optical film manufacturing method using the same, which can maintain transparency and an orientation angle even after the haze without stretching.

Still another object of the present invention is to provide a film forming roll and an optical film manufacturing method using the same, which can greatly improve the viewing angle of a liquid crystal display during film forming.

Still another object of the present invention is to provide a film forming roll and an optical film manufacturing method using the same, which can improve light leakage caused by liquid crystal compensation during film formation.

One aspect of the present invention relates to a film forming roll. The film forming roll has a rotatable cylindrical inner member; A surface member formed at intervals from an outer circumference of the cylindrical inner member; And a liquid layer filled between the cylindrical inner member and the surface member.

The material of the cylindrical inner member and the surface member may be a metal.

The liquid layer may be at least one selected from the group consisting of water and oils.

The surface member may have a diameter d2 of the contact center portion larger than a diameter d1 of the end portion.

The diameter d2 of the contact center portion may be about 0.01 to about 5.00% greater than the diameter d1 of the end portion.

Another aspect of the invention relates to a method for producing an optical film using the film forming roll. The method comprises melt extrusion of a non-liquid crystalline thermoplastic resin; And nip molding the melt-extruded thermoplastic resin between the film forming roll and the second forming roll to form a film.

In embodiments, the film forming roll and the second forming roll may have different elastic modulus. The elastic modulus of the film forming roll may be greater than the elastic modulus of the second forming roll.

The elastic modulus of the film forming roll may be about 0.1 to about 30.0% greater than that of the second forming roll.

In embodiments, the film forming roll and the second forming roll may have a peripheral speed difference of about 30% or less.

The surface temperature of the film forming roll and the second forming roll may be less than or equal to the glass transition temperature (Tg) of the non-liquid crystal thermoplastic resin.

The surface temperature (Tr) of the film forming roll may satisfy the following equation 3:

[Equation 3]

Te x 0.4 <Tr <Te x 0.5

(Te is the thermoplastic resin temperature immediately after melt extrusion, and Tr is the surface temperature of the film forming roll).

The film forming roll and the second forming roll may have a temperature difference of about 30 ° C.

In one embodiment, the thermoplastic resin may be a resin having a negative anisotropy refractive index.

In another embodiment, the thermoplastic resin may be a resin having a positive anisotropy refractive index, and may further include stretching after forming a nip.

The stretching may be about 5 to 20% of the stretching direction in the opposite direction of travel (TD).

The stretching may be performed at a temperature lower than the glass transition temperature (Tg) of the thermoplastic resin.

The stretching may have a stretching temperature satisfying the following formula:

Td = Tg-a

(Td is the stretching temperature, Tg is the glass transition temperature of the thermoplastic resin, a is 5 ~ 20 ℃).

The present invention can express the inclination characteristics of the refractive index main axis in the film thickness direction, the surface in the single film during film formation, the inclination orientation does not occur, the inside can express the inclination orientation, ensure uniform properties in the width direction It is possible to maintain transparency and alignment angle without haze after stretching, and to greatly improve the viewing angle of the liquid crystal display, and to improve the light leakage caused by liquid crystal compensation, and a film forming method using the same. It has the effect of providing the invention.

1 is a schematic perspective view of a film forming roll according to one embodiment of the present invention.

2 is a front sectional view of the film forming roll of the present invention.

3 is a side cross-sectional view of the film forming roll of the present invention.

Figure 4 is a schematic diagram showing a process of manufacturing an optical film using the film forming roll.

5 is a cross-sectional view schematically showing an optical film manufactured by the manufacturing method of the present invention.

6 is a conceptual diagram for explaining the film β angle.

7 is a phase difference measurement result according to a film width of Example 3 and Comparative Example 1.

Film forming roll

1 is a schematic perspective view of a film forming roll according to an embodiment of the present invention, Figure 2 is a front sectional view, Figure 3 is a side sectional view. As shown in Figure 1, the film forming roll 100 of the present invention is a rotatable cylindrical inner member (10); A surface member 30 formed at intervals from an outer circumference of the cylindrical inner member; And a liquid layer 20 filled between the cylindrical inner member and the surface member.

As the material of the cylindrical inner member 10, metal, glass, ceramic, plastic, rubber, or the like may be applied, and preferably, metal.

In addition, the diameter of the cylindrical inner member 10 may be about 200mm to about 500mm.

The surface member 30 surrounds the outer periphery of the film forming roll 100 of the present invention and is formed at intervals from the cylindrical inner member 10.

The material of the surface member 30 may be a metal. As the metal, a single metal, a metal plated with a second metal, an alloy of two or more metals, and the like may be applied. For example, steel metal plated with chromium may be applied.

In embodiments, materials of the cylindrical inner member 10 and the surface member 30 may be different from each other. For example, even when the cylindrical inner member 10 and the surface member 30 are made of metal, the cylindrical inner member 10 may be made of steel and the surface member 30 may be made of steel.

The average distance between the cylindrical inner member 10 and the surface member 30 may be about 0.1 mm to about 10 mm mm. In one embodiment, the surface member may have a cylindrical shape having the same diameter as that of the end portion 31 and the contact center portion 32. In another embodiment, the surface member may have a diameter d2 of the contact center 32 greater than the diameter d1 of the end 31. That is, as shown in FIG. 3, the contact center of the film forming roll 100 has a convex jar shape. The end part 31 and the contact center part 32 make both ends the "end part" and the part in the center of the said end as the "contact center part" when observed in the direction perpendicular to the axial direction of a film forming roll here. As such, when the contact center portion of the film forming roll has a convex jar shape, uniformity of the width direction retardation and the inclination angle can be ensured. In embodiments, the diameter d2 of the contact center may be about 0.01% to about 5%, preferably about 0.01% to about 1% larger than the diameter d1 of the end. Within this range, it is possible to ensure uniformity in the width direction phase difference and the inclination angle. For example, the diameter d1 of the end portion 31 of the surface member may be about 200 mm 3 to about 500 mm mm, and the diameter d 2 of the contact center portion 32 may be about 200.02 mm to about 505.00 mm mm.

The liquid crystal layer 20 is filled between the cylindrical inner member 10 and the surface member 30.

The liquid layer may be water, oil or the like. Of these, water is preferable because it is easy to control the temperature.

Optical film manufacturing method

Another aspect of the invention relates to a method for producing the optical film. The method comprises melt extrusion of a non-liquid crystalline thermoplastic resin; And nip molding the melt-extruded thermoplastic resin between the film forming roll and the second forming roll to form a film.

4 is a schematic diagram showing a process of manufacturing an optical film using the film forming roll 100 according to an embodiment of the present invention. As shown, the thermoplastic resin melt-extruded from the die 400 is passed between the film forming roll 100 and the second forming roll 200 to be produced as an optical film 500 in the form of a film. Thereafter, passing between the third forming rolls 300 adjacent to the second forming rolls 200 may be a winding or stretching process.

In embodiments, a process of drying the melted thermoplastic resin in the die 400 may be performed. In the melt extrusion process, if the moisture content in the raw material contains a certain level or more, defects in the product in the bubble state such as orange peel may occur. In a specific embodiment, a dehumidifying dryer or a hot air dryer may be used in the drying process. The drying temperature is preferably about 20 to 200 ° C, more preferably about 50 to 150 ° C, and most preferably about 70 to 130 ° C. In the above range it is possible to remove the moisture without changing the raw material properties. The drying time of the raw material is preferably about 30 minutes to 5 hours, more preferably about 1 to 3 hours, and most preferably about 2 to 3 hours.

After the raw material is dried, the raw material is fed into the fixed quantity supply device, and then, the raw material is supplied to the extrusion facility in earnest by adjusting a predetermined amount to the raw material reservoir (hopper) installed at the inlet of the extrusion facility. At this time, in order to remove impurities that may be included in the raw material may be passed through the filtration device while primarily circulating air in the intermediate reservoir.

The dried raw material is then fed to an extruder. The extruder is divided into 3 to 5 sections depending on the temperature. The first raw material is filled in the first section of the extrusion plant screw. The first section serves to transfer the raw material to the extrusion equipment cylinder. The temperature setting of the first section is preferably about 20 ~ 350 ℃, most preferably about 150 ~ 250 ℃. The second section is where the melting of the raw material begins. The temperature setting of the second section is preferably about 150 ~ 350 ℃, most preferably about 200 ~ 280 ℃. The third section serves to convert the raw material completely into the melt. Temperature setting of the third section is about 150 ~ 350 ℃, preferably about 200 ~ 280 ℃. The fourth section increases the density of the melt by increasing the pressure of the molten raw material to ensure a stable discharge amount. Temperature conditions of the fourth section is about 150 ~ 350 ℃, most preferably about 200 ~ 280 ℃. It can pass through the mesh of the screen changer section to remove impurities contained in the molten raw material. The cubic number of the mesh is preferably about 30 to 1000 squares, and most preferably about 100 to 300 squares. It is easy to move the melt in the above range, and excellent in the ability to remove impurities. The demelted melt passes through the gear pump section, which transfers it to the T-die in a constant amount. The gear pump stores the raw material irregularly injected from the extrusion equipment cylinder in a certain space and supplies a certain amount of melt to the tie tie to minimize the change of pressure distribution. Ti-dye section is the section where the melt is finally discharged out of the extrusion facility. The shape and manufacturing thickness of the film are determined depending on the form of the T-die. Ti die types are divided into "T-shaped" dies, coat hanger dies, and fish tail dies. It can be used selectively depending on the flow of the melt.

The melt in the form of a film discharged through the die is in contact with the film forming roll 100 to have a solidified film form. In the present invention, it is possible to implement the inclination characteristics of the refractive index main axis in the thickness direction by applying the film forming roll 100 of the specific structure.

In embodiments, the film forming roll 100 and the second forming roll 200 may have different elastic modulus. As such, the film forming rolls 100 and the second forming rolls 200 may have different elasticities from each other to form various film β angles.

Preferably, the elastic modulus of the film forming roll 100 may be greater than the elastic modulus of the second forming roll 200. In an embodiment, the elastic modulus of the film forming roll 100 may be about 1.0 kPa to about 30.0 kPa% greater than the elastic modulus of the second forming roll 200. It is possible to ensure the uniformity of the width direction retardation and the inclination angle in the above range.

In addition, the film forming roll 100 and the second forming roll 200 may have a difference in peripheral speed. Here, the main speed difference is the speed at which the roll rotates. In a specific embodiment, the circumferential speed of the film forming roll 100 may be faster than the circumferential speed of the second molding roll 200. For example, the circumferential speed of the film forming roll 100 may be about 1 kPa to about 60 m / min, and the circumferential speed of the second forming roll 200 may be about 1 kPa to about 50 m / min.

Preferably, the peripheral speed difference between the film forming roll 100 and the second forming roll 200 may be within about 30%. In preferred embodiments, the peripheral speed difference may be about 0 to about 10%, more preferably about 0 to about 5%. Within the above range, there is an advantage of securing a phase difference value and an inclination angle through phase expression.

In embodiments, the surface temperature of the film forming roll 100 and the second forming roll 200 may be less than or equal to the glass transition temperature (Tg) of the non-liquid crystalline thermoplastic resin.

Thus, the melt-extruded thermoplastic resin is in contact with the film forming roll 100 and the second forming roll 200, the film inside the film when the Tg temperature or more, while the film surface is different to the Tg temperature or less. When the forming rolls of the film forming roll 100 and the second forming roll 200 are driven in a state where the film 성형 surface and the forming temperature difference are generated, different shearing forces are generated on the surface and the inside of the film and are inclined in the thickness direction. It will have an angle.

In embodiments, the surface temperature Tr of the film forming roll 100 may satisfy the following Equation 3:

[Equation 3]

Te x 0.4 <Tr <Te x 0.5

In the above range, the surface layer may not be oriented in the film thickness direction, and may have a structure in which only the inner layer is inclined.

In an embodiment, the surface temperature (Tr) of the film forming roll 100 is about 20 ~ 200 ℃, preferably about 50 ~ 150 ℃, most preferably about 80 ~ 130 ℃. It is possible to secure the phase difference value and the inclination angle through the phase expression in the above range. In addition, the surface temperature of the second forming roll 200 is about 20 ~ 200 ℃, preferably about 80 ~ 130 ℃. It is possible to secure the phase difference value and the inclination angle through the phase expression in the above range. The temperature difference between the film forming roll 100 and the second forming roll 200 is about 2 to 50 ° C, preferably about 5 to 30 ° C, and more preferably about 5 to 15 ° C. It is possible to secure the phase difference value and the angle of inclination through phase expression in the above range. In addition, the surface temperature of the third forming roll 300 may be about 20 ~ 180 ℃, preferably about 50 ~ 120 ℃.

The thermoplastic resin may be a resin having a negative anisotropic refractive index, such as an aromatic vinyl resin, an acrylic resin, or the like, or a resin having a positive anisotropic refractive index, such as a cycloolefin resin, a polycarbonate resin, a polyolefin resin, or the like.

When the thermoplastic resin is a resin having a positive anisotropy refractive index, the method may further include stretching after nip molding. In the specific example, the stretching may be biaxial stretching, and stretching may be performed at about 5 to 30% of the traveling direction in the opposite traveling direction (TD). In the above range, there are advantages in securing a phase difference value and preventing the inclination angle from falling. Preferably, the stretching may be performed at about 8 to 25%, more preferably at about 10 to 20% relative to the driving direction in the opposite traveling direction (TD).

Preferably, the stretching may be performed at a temperature lower than the glass transition temperature (Tg) of the thermoplastic resin. For example, the stretching may be performed at a temperature about 5 to 20 ° C. lower than the glass transition temperature (Tg) of the thermoplastic resin. In the above range, there is an advantage that a phase difference value and an inclination angle can be secured through phase expression.

For example, the drawing may have a drawing temperature satisfying the following formula:

Td = Tg-a

As described above, when the film having the inclination angle in the thickness direction is stretched in the extruded film, the film is stretched at a low magnification at a temperature lower than the glass transition temperature (Tg), whereby the inclination characteristic during extrusion molding can be efficiently maintained.

In another embodiment, when the thermoplastic resin is a resin having a negative anisotropy refractive index, internally oriented characteristics may be obtained without a drawing process after nip molding.

After the molding process is completed, the film is finally wound up. Preferably, the film may be wound after trimming the uneven portions of both side ends of the film.

In the optical film manufactured as described above, the surface may not be inclined in the film thickness direction and may be inclined in the film thickness direction as shown in FIG. 5. As described above, the optical film manufactured by the above method may be formed to have different orientations depending on the surface and the interior thereof, thereby improving a viewing angle and light leakage. In addition, since the manufacturing of the optical film having different inclination orientations according to the surface and the inside can be performed in a single extrusion process, the process can be shortened and manufacturing cost can be reduced.

6 is a conceptual diagram for explaining the film β angle. The film inner layer 500c may have a film average β angle of about 5 to 35 degrees, preferably about 12 to 30 degrees, defined as an angle at which orthogonal nicotine transmittance is minimum. The film? Beta angle is an intercept alignment angle, and is an angle formed between the z axis in the thickness direction and the z 'axis perpendicular to the orientation plane, as shown in FIG. 6. The film? Average?? Angle can be obtained between the polarizing plates and observed at the orthogonal nicotine to obtain an angle at which orthogonal nicotine transmittance is minimum.

The film inner layer 500c may have different values of the film β angles along the z-axis in the thickness direction. For example, the film β angle may be about 21 to 27 degrees at the position of about 10 to 20 μm from the surface of the film, whereas the film β angle may be about 15 to 20 degrees at the position of about 70 to 80 μm from the surface of the film. Thus, the inclination orientation is different according to the film thickness, and the film β angle has different distribution. Preferably, the ratio of the maximum β angle β1 and the minimum β angle β2 in the film inner layer (β1 / β2) may be about 1 to 1.8, more preferably about 1.1 to 1.5. In embodiments, the average β angle may be about 5 to 40 degrees, for example, about 15 to 35 degrees.

The optical film 500 may have an in-plane retardation value Ro of about 550 nm to about 150 dB at 550 nm.

[Equation 1]

Ro '= (nx-ny') × d

(Wherein nx and ny 'are the refractive indexes in the x- and y'-axis directions, respectively, and d is the thickness of the film).

The optical film may have a thickness direction retardation value Rth defined by Equation 2 at 550 nm in a range of about 0 Hz to about 200 Hz.

[Equation 2]

Rth '= [(nx + ny') / 2-nz '] × d

(In the above, nx, ny 'and nz' are the refractive indices in the x-axis, y'-axis and z'-axis directions, respectively, and d is the thickness of the film).

In embodiments, the thickness d of the optical film may be about 30 to about 110 μm, preferably about 50 to about 100 μm.

The optical film produced by the above method may be directly laminated on the polarizing device to produce a polarizing film. Since the optical film manufactured according to the method of the present invention is not inclined to the surface but is inclined only to the inner layer, it is possible to secure an excellent viewing angle even in the vertical alignment mode liquid crystal. You can improve the light spring mura.

실시예Example

실시예 1~6Examples 1-6

The thermoplastic resin (JSR Arton RX4500) is melt-extruded at 250 ° C. with a T die, and the film forming roll 100 and the rigid metal are filled with water between the steel cylindrical inner member and the stainless steel surface member as shown in FIG. 4. The melt was passed through the rolls 200 to prepare a film. At this time, the peripheral speed ratio between the film forming roll 100 and the rigid metal roll 200 was changed as shown in Table 1 to prepare an optical film, and then laminated with a polarizing film. The surface temperatures of the film forming rolls 100 and the rigid metal rolls 200 and 300 were the same.

Property evaluation method

(1) Ro 'and Rth' values: Wavelengths in the direction perpendicular to the sample film surface and inclined ± 45 ° from the film plane normal using Axo scan (OPMF-2 eries of Axometrics Inc.) for the produced film. The retardation value at 550 nm was measured. Here, the hypothesis of the average refractive index may be a polymer handbook (JOHN WILEY & SONS, Inc.) and values of catalogs of various optical films.

(2) average β angle: measured using Axo scan. This is calculated as an average value of β angles distributed in the overall film thickness direction.

Using an image analysis program, the luminance distribution of the polarizing microscope image was analyzed for each angle, and the average brightness was calculated after dividing the light into nine equal intervals in the film thickness direction. Next, after plotting the angle and the average luminance (PLOT), the film β angle was obtained. The p-angle distribution was plotted for each thickness and then averaged.

(3) Viewing angle: A lateral angle at which CR = 10 or more was measured through EZ contrast.

Table 1

	Speedboat	Roll temperature (℃)			Film optical properties
	# 1 ~ # 2 roll speed	Crown Metal Elastic Roll (# 1)	Rigid Metal Roll (# 2)	Rigid Metal Roll (# 3)	Ro (nm)	Rth (nm)	β (°)
Example 1	1.010	123	123	115	7.2	38.2	22.2
Example 2	1.015	123	123	115	12.7	44.4	26.6
Example 3	1.020	123	123	115	18.5	50.4	29.9
Example 4	1.025	123	123	115	24.7	57.0	31.8
Example 5	1.030	123	123	115	34.5	66.7	32.1
Example 6	1.035	123	123	115	43.1	75.0	32.7

As shown in Table 1, when applying the film forming roll of the present invention it can be confirmed that the inclination characteristics of the refractive index main axis in the thickness direction.

비교예 1Comparative Example 1

Except that the rigid metal roll was applied instead of the film forming roll 100 was performed in the same manner as in Example 3. The retardation of the prepared film is measured and shown in FIG. 7.

As shown in Figure 7, it can be seen that when applying the film forming roll of the present invention has a substantially uniform phase difference over the film width.

실시예 7~9 및 비교예 2~3 : 연신온도에 따른 물성변화Examples 7 to 9 and Comparative Examples 2 to 3 change in physical properties depending on the stretching temperature

It was carried out in the same manner as in Example 2 except that the stretching step under the stretching conditions as shown in Table 2.

TABLE 2

	Process conditions			Properties
	Drawing temperature (℃)	Drawing speed (m / m)	Elongation (%)	R0 '(nm)	Rth '(nm)	Orientation angle (°)	Normal viewing angle / Hashi viewing angle (°)
Example 7	120	4	10	70	160	20	50-88 / 85
Example 8	123			60	145	16	50 ~ 88/85
Example 9	125			50	125	15	50 ~ 88/85
Comparative Example 2	130			40	90	10	30-50 / 50-60
Comparative Example 3	138			30	60	2	20-40 / 40-60

As shown in Table 2, it can be seen that Examples 7 to 9 have a high viewing angle compared to Comparative Examples 2 to 3 where the stretching temperature is higher than the Tg of the resin.

Claims

Rotatable cylindrical inner members;

A surface member formed at intervals from an outer circumference of the cylindrical inner member; And

A liquid layer filled between the cylindrical inner member and the surface member;

Film forming roll comprising a.
The film forming roll according to claim 1, wherein the cylindrical inner member and the surface member are made of metal.
The film forming roll according to claim 1, wherein the cylindrical inner member and the surface member are made of metal.
The film forming roll according to claim 1, wherein the surface member has a diameter d2 of a contact center portion larger than a diameter d1 of an end portion.
5. The film forming roll of claim 4 wherein the diameter d2 of the contact center portion is about 0.01 to about 5.00% greater than the diameter d1 of the end portion.
Melt extruding the non-liquid crystal thermoplastic resin; And

The melt-extruded thermoplastic resin is nip formed between the film forming roll and the second forming roll of any one of claims 1 to 5 to form a film form;

Comprising a step;

Optical film production method using a film forming roll.
Melt extruding the non-liquid crystal thermoplastic resin; And

The melt-extruded thermoplastic resin is nip formed between the film forming roll and the second forming roll of any one of claims 1 to 5 to form a film form;

Comprising a step;

Optical film production method using a film forming roll.
The method of claim 7, wherein the elastic modulus of the film forming roll is larger than the elastic modulus of the second forming roll.
The method of claim 8, wherein the elastic modulus of the film forming roll is 1.0 to 30.0% greater than the elastic modulus of the second forming roll.
The method of claim 6, wherein the film forming rolls and the second forming rolls have a peripheral speed difference of about 30% or less.
The method of claim 6, wherein the surface forming temperature of the film forming roll and the second forming roll is less than or equal to the glass transition temperature (Tg) of the non-liquid crystalline thermoplastic resin.
12. The method of claim 11, wherein the surface temperature Tr of the film forming roll satisfies Equation 3.

[Equation 3]

Te x 0.4 <Tr <Te x 0.5

(Te is the thermoplastic resin temperature immediately after melt extrusion, and Tr is the surface temperature of the film forming roll).
The method of claim 11, wherein the film forming rolls and the second forming rolls have a temperature difference of about 30 ° C. or less.
The method of claim 6, wherein the thermoplastic resin is a resin having a negative anisotropy refractive index.
The method of claim 6, wherein the thermoplastic resin is a resin having a positive anisotropy refractive index, and further comprising stretching after nip molding.
16. The method of claim 15, wherein the stretching is about 5 to 20% of the stretching direction in the opposite direction of travel (TD).
The method of claim 15, wherein the stretching is performed at a temperature lower than a glass transition temperature (Tg) of the thermoplastic resin.
18. The method of claim 17, wherein the stretching has a stretching temperature satisfying the following formula:

Td = Tg-a

(Td is the stretching temperature, Tg is the glass transition temperature of the thermoplastic resin, a is 5 ~ 20 ℃).