TWI359075B - Device for manufacturing optical film and method f - Google Patents

Description

1359075

* File: TW4214F IX. Description of the Invention: [Technical Field of the Invention] The present invention relates to an apparatus and method for fabricating an optical-film having excellent optical characteristics, and particularly relates to a process having a smooth surface and excellent optics. The device and method for the characteristic optical film, and the optical film can be used as an internal component of a liquid crystal display or an optical storage medium, for example, a digital video disc using blue light. ® [Prior Art] With the increasing demand for flat panel displays such as liquid crystal displays, plasma display panels (PDPs), etc., the demand for optical films suitable for the internal components of flat panel displays has also increased significantly. The optical film has characteristics such as optical homogeneity (?1: 丨(^14〇打〇1^), suitable optical phase difference), and is therefore suitable for the above-mentioned components. In particular, it is used in a large The optical film of the screen must have very uniform optical properties. Today's display manufacturing technology focuses on the development of wider and thinner displays. Therefore, optical films must have optical homogeneity and must be only as thin as possible. And have a low phase difference, and if necessary, have sufficient thermal resistance. In addition, 'high-density digital audio and video discs using blue light as a light source are produced, for example, blue-ray discs. , with a thin film on the surface. In order to accurately read the fine pattern, when the light passes through the protective film, it will be 1359075

File: TW4214F Avoid scattering and interference of light. Therefore, the film must have excellent optical properties and a highly uniform thickness. Conventional methods for fabricating thin optical films having optical homogeneity and low phase difference include a solvent-casting method and a melt-extrusion method. The solvent washing method comprises: dissolving a polymer in a solvent; applying the dissolved polymer to an upper surface of a flexible belt; and volatilizing the solvent. The melt extrusion method comprises: smashing a resin into an extruder; extruding the melted resin through a mold; and processing the extruded resin using a metal or rubber roller. Although the above method can produce an optical film having a uniform thickness and excellent optical characteristics, it is difficult to recover a solvent which is not exposed to the atmosphere, and due to low productivity, even if a high-priced device is put into place, economic efficiency is still high. Low. In other words, although the apparatus of the second method described above is relatively inexpensive and has high productivity, the optical film has uneven thickness and low optical characteristics. In particular, one of the conventional methods of fabricating optical films involves the step of passing a resin through a cooling roller after the steps of melting and extruding to obtain a smooth surface and a uniform thickness. However, the disadvantages of this method are as follows: First, because the resin passes through the high pressure between the rollers, high stress is generated inside the resin to lower the optical properties of the resin. Second, when the film is kept at a high temperature for a long period of time, the high stress inside the resin causes the film to be deformed. Third, an uneven block is formed between the rollers, 1359075

• *FiIe: TW42I4F causes the generation of a die Hne on the film. • Fourth, the change of the diameter or surface roughness of any roller and the shape of the roller will be transferred to the film, so it is difficult to produce a film with a uniform thickness. Fifth, after the film passes the roller, The difference in cooling rate between the two sides of the film causes bending characteristics. Such film bending properties reduce the value of the product. Finally, it is known that after the free space between the stamper and the stagnant zone has undergone a process of free fall, the resin can not avoid directionality. Thus, the directivity of the resin causes deterioration of optical characteristics. In addition to the above-described method of forming the thickness and surface of the film between the rollers, the method of producing the optical film is applied to a resin so that the tree is intended to flow on the surface of the large diameter cooling roller. Compared to the above method, this method makes it easier to produce an isotropic film. However, although one surface of the film in contact with the roller is smooth, the surface of the thin film that is in contact with the working gas is thick, thereby limiting the optical properties of the film. * In addition, due to the fact that only a single surface is in contact with the roller during the processing step, the film exhibits a 'f-curvature characteristic, which causes deterioration of the product. Since the conventional method has the aforementioned problems, the film producer improves the fusion and extrusion methods to obtain an optical film having excellent optical characteristics. However, the resin 'is, for example, the prior art polyethylene terephthalate and polycarbonate, which has a high refractive index due to its structural characteristics, so it is difficult to obtain a low phase difference; and since it is a solution extrusion method, Therefore, the resin should have optical uniformity 1559075

tFile: TW4214F is also more difficult. Thus, although such resin characteristics have advantages of low cost and excellent permeability, there are still application limitations as materials for producing high-quality large-screen displays. SUMMARY OF THE INVENTION The present invention is to solve the problems of the prior art. According to one aspect of the present invention, it is proposed to produce a low uniform phase difference, high optical uniformity, excellent thickness uniformity, excellent surface roughness and Apparatus and method for optical film having long-term dimensional stability at high temperatures. According to one aspect of the invention, a device for making an optical film is proposed. It includes an extruder, a die, a flexible band, and a calender roll. The extruder is used to compress and discharge one of the molten resin. A stamper is provided to the extruder to determine the thickness of the resin extruded from the stamper. The resin extruded in the stamper is applied to a flexible belt. Caiguang is installed on the resin that is applied to the flexible belt to compress the air contact surface of one of the resins. According to another aspect of the invention, a device for making an optical film is provided. The utility model comprises an extruder, a stamper, a flexible belt and a flexible compression skin = an extruder for compressing and discharging one of the melted resins. The stamper is provided for squeezing to a thickness of the resin extruded from the stamper. The tree that is dispensed from the stamper is applied to a flexible belt. The flexible compression belt is placed on one of the paths of the resin coated on the resin to compress one of the resin air contacts 1359075

FiIe: TW4214F Face 0 According to still another aspect of the present invention, a method of making an optical film is proposed. Using a device for making an optical film, the device includes an extruder, a stamper, a ribbed belt, a yoke or a flexible compression belt. The extruder is used to compress and discharge one of the molten resin. A stamper is provided to the extruder to determine the thickness of the resin extruded from the stamper. The tree t which is extruded into the stamper is applied to a flexible belt. A calender roll or flexible compression belt is disposed on one of the paths of the resin coated on the flexible belt to compress the outer gas contact surface of the resin. The distance between the stamper and the flexible belt is 3 mm or less, and the pressure of the calender roll or flexible compression belt is 1 bar (leaf) or less than 10 bar. In order to make the above-mentioned contents of the present invention more comprehensible, the following detailed description of the preferred embodiments and the accompanying drawings will be described in detail below: 实施 [Embodiment] According to an aspect of the present invention, an optical fabrication method is proposed. The film of the farm = including - squeezer, - Tibetan, - flexible belt and - Caiguang pro. The transducer is used to compress and discharge the molten resin to provide a thickness for the press mold. Resin extruded in the stamp: coated = sexual belt. The calender roll is set to "send" (4) on the tree path 35 on the flexible belt to 'press the air-air contact surface. Set. = Another aspect of the invention' proposes a tape for making an optical film. '. Extrusion, - compression mold, - flexible belt and - flexible compression skin state to compress and discharge one of the resin melted. The die is provided in the squeeze 1359075

File: TW4214F An effective spacing of 30 mm or less, preferably 15 or less than 15 mm. It is worth noting that the stamper 12 is not in contact with the flexible belt 200. When the distance between the stamper 120 and the flexible belt 200 is larger, the resin 1 自由 is freely dropped by its own weight, so that the resin produces the orientation of the polymerized polymer chain. Thus, the optical properties of the final product are deteriorated. The pull-up belt 200 疋 a metal belt is disposed between two or more than two rotating rollers 220 and is actuated by a caterpiUar manner. The surface roughness of the flexible belt 2 直接 directly affects the surface quality of the resin 10, and therefore, the flexible belt 2 〇〇 preferably has a tenth of an average thickness (Rz ) 0 · 1, preferably 〇. 〇7 or less than 〇〇7. The ten-point average thickness is the difference between the average distance of the highest peak and the average distance of the five-point lowest trough from five points of a specific line (reference Hne). Wherein the particular line is parallel to a mean line of the profile of the roughness profile whose length exceeds a predetermined sample length. Preferably, the temperature of the flexible belt 20 can be extruded from the stamp 12 by controlling the temperature of the rotating roller 220 or by using a separate heater or cooler as shown. After you ± π, the resin 10 is transported between the flexible belt 200 and the calender roll 300. In the case of a slight thickness adjustment of the crucible 1 , the light of the resin and the film of the S ^ are obtained. The surface is very flat. The pressure position between the flexible belt 200 and the calender roll 300 is ^ ^ ^ ι is a relatively low pressure 0 13 1359075

*File: TW4214F The effective pressure between the flexible belt 200 and the calender roll 300 is 10 bar or less, preferably 5 bar or less. If the pressure between the flexible belt 200 and the calender roll 300 is high, one of the films may be out of phase. As a result, the optical properties of the final product deteriorate. The resin 10 may include a polycarbonate-based resin, a ring polymer based resin, a polynorbornene based resin, and a polyethylene terephthalate-based resin. . In particular, any of these resins, such as polycarbonate oil and the like, are used as optical applications. A variety of additives are added to the resin to complement or enhance mechanical properties. Such resins contain a low molecular weight oligomer or monomer. When the resin is discharged from the stamp, Rapid pressure drop and high temperature, evaporable or sublimate is ejected from the resin and diffused into the outside world. These diffused substances or gases may stick to the surface of the stamper 120 or the calender roll 300 or the flexible belt 200, thus causing a defect such as a mold line. For a general film, a gas discharge device 150 is disposed around the stamper 120 to adsorb the additives, oligomers, and monomers ejected from the resin, and forcibly discharges the substances to the outside. However, for some optical products, the air flow caused by the gas discharge interferes with the flowability of the resin through the stamper and reduces the optical characteristics of the film, which is a disadvantage of the prior art using a gas discharge device. 14 1359075

1 'File: TW4214F However, according to the present embodiment, since the distance between the stamper 120 and the flexible belt 200 is small, the influence of the disadvantage of the gas discharge device 150 is minimized, and it is noted that the gas discharge device 150 is not an essential component of the invention. Depending on the resin used in the process, some resins produce very little or no gas at all, eliminating the need for gas discharge devices. In such a case, a sufficient number of vent holes are provided in the middle of the extruder, and the demand for the gas discharge device is thus lowered. Figure 2 is a schematic view of an apparatus for fabricating an optical film in accordance with a second embodiment of the present invention. As shown in Fig. 2, the apparatus according to the second embodiment includes an extruder 100, a stamper 120, a flexible belt 200, and a flexible compression belt 400. The extruder 100 is used to compress and discharge one of the melted resins. A stamper 120 is provided to the extruder 100 to determine the thickness of the resin extruded from the stamper 120. The resin extruded in the stamper 120 is applied to the flexible belt 200. The flexible compression belt 400 is disposed on one of the paths of the resin coated on the flexible belt 200 for compressing one of the air contact faces of the resin. As shown in Fig. 2, the same elements of the second embodiment as those of the first embodiment are given the same reference numerals as the first embodiment. Therefore, the description of the second embodiment can be referred to the portion related to the second embodiment in Fig. 1. As shown in Fig. 2, differences between the second embodiment and the first embodiment in Fig. 1 will be described below. The flexible compression belt 400 has the same function as the first embodiment of the optical roller 300 and is disposed on one of the transport resins 10 for compressing an air contact surface of the resin 10. The flexible compression belt 400 is disposed on two or more than two rotating rollers

< S 15 1359075

'File: TW4214F between wheels 410 and 420 and operated by a crawler. Although the flexible compression belt can be made of metal, (4), _, etc., the preferred compression belt is made of metal when considering the degree of mold release associated with the resin. One principle of compressing a resin with a flexible compression belt 400 is as follows. The flexible compression belt 400 is supported and driven by two rotating rollers 410 and 420 disposed above the flexible belt 2〇〇. The pressure between the flexible belt 200 and the flexible compression belt 4〇〇 of the resin 1〇 is thus adjusted to the thickness. The pressure between the flexible belt 200 and the flexible compression belt 400 is relatively low. In the second embodiment, the pressure between the flexible belt 2 〇〇 and the flexible compression belt 4 系 is 10 bar or less, preferably 5 bar or less. This pressure value is the same as that of the calender roll 3A of the first embodiment of Fig. 1. Next, a method of producing an optical film using any of the above devices will be described. The method uses an apparatus for producing an optical film, comprising an extruder for compressing and discharging one of the melted resins; a stamper is provided to the extruder to determine a thickness of the resin extruded from the stamper; a flexible belt, The resin extruded in the stamper is applied to the flexible belt; a calender roll or a flexible compression belt is disposed on one of the paths of the resin coated on the flexible belt, and is in contact with one of the compressed resins. surface. Preferably, in order to prevent the stamper from contacting the flexible belt, the distance between the stamper and the flexible belt is 30 mm or less. 1359075

File: TW4214F The calender roll or flexible compression belt has a pressure of ίο巴 or less than 10 bar, and the flexible belt has a transport speed of 5 to 100 meters per minute (m/min). Therefore, after cooling, the film is peeled off from the flexible belt at a glass transition temperature Tg or lower than the glass transition temperature Tg. If necessary, measure the parameters related to the thickness and phase difference of the film in the subsequent elongation process. In order to avoid the directionality of the resin, preferably, the stamper and the flexibility

The spacing between the belts can be small. If one of the pressures acting on the resin is excessive, the optical characteristics may be deteriorated due to the generation of stress. The transport speed of the belt is directly related to the production speed. A production speed of 100 &amp; ft/min causes a large amount of resin to cause rapid flow during the process of passing through the stamper, thereby causing the directionality of the resin to deteriorate, and the optical characteristics are deteriorated. However, a production speed of less than 5 meters per minute would reduce economic efficiency. Therefore, the flexible belt is preferably transported at a speed of 5 to 100 meters per minute. 々 The following is a comparative example and a second comparative example of an optical film (example) produced by the apparatus and method according to the present invention and a conventional calender roll or a cooling roll) _^ <Example> The apparatus using the first figure An optical polycarbonate film produced. t _ After melting a polycarbonate resin by the extruder 1 , the molten tree = 铋 is applied by a stamper 120 to a flexible belt 200, between the die lips of the stamper 12 One distance can be adjusted automatically and independently. Stamper 1359075

The 'File: TW4214F 120 and one of the flexible belts 200 are maintained at a distance of 8 mm, and the gas discharge device 150 is disposed on the front side and the rear side of the stamper to remove the sublimate and the evaporant. When the resin 10 coated on the upper surface of one of the flexible belts 200 passes through the stone tooth roller 300, it is processed so that the resin has excellent surface characteristics with respect to one surface (air contact surface) of the flexible belt. At the same time, the pressure between the calender roll 300 and the flexible belt 200 is maintained at 2 bar. When the resin is peeled off from the flexible belt, the resin passes through a non-contact thickness measurement system (not shown), and then the resin information is transferred to a compression molding system' and by a thermal open bolt system (thermal Expansion bolt system) to adjust the distance between the lips. Under the operation of such a thickness adjustment system, a film having a thickness of 1 μm (/zm) was obtained. Even when left in a high temperature environment for a period of time, the film has a high degree of optical and mechanical uniformity and no optical or mechanical deformation. As such, the film is suitable for a variety of different applications. <First Comparative Example> As shown in Fig. 3, after melting a resin with an extruder 1 , a molten resin is inserted between the calender rolls 30 by using the same stamper 120 as the above-described example. . The calendar between the stone tooth 30 is set at 3 bar, and the distance between the stagnant zone from the die 12 砑 to the calender roll 30 is 8 cm (cm). After the rouge passed a total of three pulverizing rolls, the resin was passed with the above 1359075

, File: TW4214F The same thickness measurement system "last" obtained a film with 1 micron (# m). <Second Comparative Example> As shown in Fig. 4, after melting a resin by the extruder 100, the molten resin was applied to a cooling roller 40 by using the same stamper 12 as the above-described example. The resin is applied in the tangential direction of the surface of the roller and is separated from the cooling roller 4 by about 180 degrees around the cooling roller 40. In this example, the distance between the stamper 120 and the cooling roller 4〇 is maintained at 6 cm. Then, after the resin passes through the additional roller (additi〇nal r〇11), the resin passes through the same thickness measurement system as the above example. Thus, a film having a thickness of 100 μm was obtained. Table 1 Haze Phase difference Thickness uniformity Shrinkage bending phenomenon Mold line measurement method ASTM-1003 Standard deviation ASTM D256 Naked eyes Naked eyes Unit % nm μια %, MD/TD - — Example 0.3 21 0.4 &lt;1 /&lt;1 did not occur good first control example 0.3 340 0.8 31/-7 did not occur good second control example 0.5 82 1.4 4/2 occurs as shown in Table 1, compared to conventional calender rolls or cooling rollers The optical film of the invention has excellent optical properties, low shrinkage, and good thickness.

*Fi!e: TW4214F degree uniformity. It can be seen from Table 1. Compared with the film of the comparative example, the sample old amine has a very stable shrinkage ’ and has a (four) grade with the rate of the cast ship casting method. Among them, the melt-dye casting method is well known to produce a shrinkage rate or a shrinkage rate. Low shrinkage means that the film has a high temperature at a high temperature for a period of time.

The film of the ruler has a low thickness deviation as compared with the film of the comparative example. Regarding the haze and the mold line, although the method of using a plurality of stone tooth photo-affinities as shown in the first comparative example can provide excellent characteristics. As shown in Table i, the film of the example also provides an excellent grade of the same grade. The phase difference is evaluated as the most important factor for whether a film is suitable for optical components. The film of the example exhibits a non-hanging phase difference compared to the film of the secret extrusion method, and the low recording also indicates that the film of the example has a lower external stress during the manufacturing process.

In general, during the manufacturing process, the film is cooled as the film surrounds the roller. Due to the round shape of the roller, the film also undergoes a bending phenomenon. That is to say, the second comparative example also experienced a bending phenomenon due to the round shape of the roller, but the first comparative example did not have a bending phenomenon. However, in order to avoid or eliminate such a bending phenomenon, a very strict process and time control is required as a process condition. However, because when the film is cooled to a suitable level, the example film does not wrap around the roller, so no bending occurs, so it can produce a high 20 1359075

File: TW4214F quality film, so it is much easier to manage in production. As a result of the above examples, the film of the present invention has long-term dimensional stability, low bending properties, and excellent surface characteristics at various levels of optical properties at various levels. The apparatus and method for fabricating an optical film disclosed in the above embodiments of the present invention can have excellent optical characteristics such as a low uniform phase difference and a low haze shape, low shrinkage and bending characteristics, excellent surface characteristics and uniform thickness. The surface of the coated resin is processed by applying a molten resin to a flexible belt and in a low pressure environment with a calender roll or a flexible compression belt. In view of the above, the present invention has been disclosed in a preferred embodiment, and is not intended to limit the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

21 1359075

'File: TW4214F BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing an apparatus for fabricating an optical thin film according to a first embodiment of the present invention. Fig. 2 is a schematic view showing an apparatus for producing an optical film according to a second embodiment of the present invention. Fig. 3 is a view showing the arrangement of the apparatus for producing an optical film of the first comparative example. Fig. 4 is a view showing the intention of the apparatus for producing an optical film of the second comparative example. [Description of main component symbols] 10: Resin 30, 300: calender roll 40: cooling roller 100: extruder 120: stamper • 150: gas discharge device 200: flexible belt 220, 410, 420: rotating roller '400 :Flexible compression belt 22

Claims (1)

1359075 July 25, 1995 Correction Replacement Page X. Patent Application Range: 1. A device for making an optical fi lm comprising: an extruder for compression and Dissolving one of the trees; a die; a die is provided to the extruder to determine a thickness of the resin extruded from the die; a flexible band extruded into the die The tree is coated on the flexible belt; and a calender roll is disposed on one of the paths of the resin coated on the flexible belt to compress the air of the resin The contact surface, wherein the stamper is spaced from one of the flexible belts by 30 mm or less. 2. A device for making an optical film, the device comprising: an extruder for compressing and discharging one of the molten resin; a stamper provided to the extruder to determine the pressure of the resin from the press Forming a thickness; a flexible belt, the resin extruded from the stamp is applied to the flexible belt; and a flexible compression belt disposed on the flexible belt One of the resins is routed to compress the air contact surface of one of the resins. 3. The device of claim 2, wherein the stamp is spaced apart from the flexible belt by 30 mm or less. 4. The device of claim 1 or 2, further comprising: 23 1359075 July 25, 100 revised replacement page A gas discharge device disposed around the stamper. 5. The surface roughness of one of the flexible belts is a ten point average roughness (Rz) o. 1 or less than a ten point average roughness of 0.1, as described in claim 1 or 2. 6. The apparatus of claim 1 or 2, further comprising: a separate heater or cooler for adjusting the temperature of the flexible belt. 7. A method of making an optical film, using a device for making the optical film, the device comprising an extruder for compressing and discharging one of the melted resin; and a stamper for providing the press Determining a thickness of the resin extruded from the stamper; a flexible belt, the resin extruded into the stamper is applied to the flexible belt; and a calender roll or a flexible compression belt, Providing a path for transporting one of the resins coated on the flexible belt to compress an air contact surface of the resin; wherein the distance between the stamp and the flexible belt is 30 mm or less The pressure of the calender roll or the flexible compression belt is 10 bar or less. 8. The method of claim 7, wherein the flexible belt has a transport speed of 5 to 100 meters per minute (m/min). 9. The method of claim 7, wherein the resin is peeled from the flexible belt when the glass transition temperature Tg of the resin is lower than the glass transition temperature. 10. The method of claim 7, wherein the distance between the stamp and the flexible belt is 15 mm or less. The method of claim 7, wherein the resin is selected from the group consisting of a polycarbonate-based resin and a polyacrylic acid vinegar (a). A composition of a polymethylmethacrylate resin, a ring polymer based resin, a polynorbornene based resin, and a polyethylene terephthalate-based resin. 25