TW202045597A - Method for manufacturing optical film and apparatus for manufacturing optical film - Google Patents

Abstract

The present invention provides a method for manufacturing optical film and an apparatus for manufacturing optical film capable of being performed with stable steps, having stable quality, and further capable of reducing material cost. A method for manufacturing an optical film 4 according to one embodiment of the present invention is a method for manufacturing an optical film by applying N treatments (N is an integer of 1 or more) on a long film 2, wherein the N treatments are performed while the film is transported, and positions of first ends and second ends 2a, 2b of the film are continuously acquired at each of a plurality of locations 20 during the transportation. When the distance between a reference position B in the width direction of the film and the position of a first end is taken as the first width, and the distance between the reference position and a second end is taken as the second width, the reference position is calculated based on a first acquiring result at positions of a first end and a second end at an upstream location among two locations selected from a plurality of locations, and the difference of a second change rate of the second width from a first change rate of the first width is calculated based on a second acquiring result at positions of a first end and a second end at a downstream location among the two locations and the first acquiring result.

Description

Optical film manufacturing method and optical film manufacturing device

The present invention relates to a method for manufacturing an optical film and an optical film manufacturing device.

Generally, the optical film is manufactured by conveying the film on one side and performing at least one treatment for imparting desired optical properties on the other side. For example, when the optical film is a polarizing film, at least one treatment for imparting linear polarization characteristics as optical characteristics is performed on the film. When the optical film is manufactured as described above, the width of the film will change during the process of manufacturing the optical film from the film. It is known that when the film is transported, the rate of change of the film width on the upstream side and the film width on the downstream side is called neck-in rate ((refer to Patent Document 1). In the manufacture of optical films In the process, when the shrinkage ratio of the film deviates from the preset allowable range (management width), the film may break or the thickness of the film may deviate from the desired thickness. Therefore, in order to appropriately manufacture the optical film, shrink The management of the frame rate is very important.

[Prior Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 8-226811

Generally, the reduction ratio is calculated for the full width of the film. However, even if the reduction rate of the full width of the film is within the desired range, there will be a width from the reference position in the width direction of the film to the end of one side of the film (hereinafter referred to as "the first Width"), and the variation of the width from the reference position to the other end of the film (hereinafter referred to as "second width"). In this case, for example, the load on the transport roller that transports the film is locally increased, and equipment loss is likely to occur. When equipment is missing, the optical film becomes defective or the film breaks. When the variation of the first width and the second width is different, the film thickness in the width direction is likely to deviate from the desired state. In this way, if the film thickness deviates from the desired state, an optical film with desired uniform optical characteristics cannot be obtained. Therefore, the material used to manufacture the optical film is wasted in vain, resulting in an increase in material cost.

Therefore, the object of the present invention is to provide an optical film manufacturing method and an optical film manufacturing apparatus that can be implemented in stable steps, not only have stable quality, but also reduce material costs.

One aspect of the optical film manufacturing method of the present invention is a method of manufacturing an optical film by performing N treatments (N is an integer greater than 1) on a long film; the foregoing method is performed while conveying the film The foregoing N processing; in the foregoing conveying, the positions of the first end and the second end in the width direction of the film are continuously obtained at a plurality of locations; the positions of the first end and the second end in the width direction of the film are When the distance between the reference position and the position of the first end portion is set as the first width, and the distance between the reference position and the second end portion is set as the second width, according to the two selected from the plurality of positions The reference position is calculated based on the first obtained result of the positions of the first end and the second end in the upstream part of the part, and the reference position is calculated based on the first obtained result and the downstream part of the two parts. of Based on the second acquisition result of the positions of the first end and the second end, the difference between the first rate of change of the first width and the second rate of change of the second width is calculated.

Another type of optical film manufacturing apparatus of the present invention is provided with: N processing units (N is an integer greater than or equal to 1) for performing at least processing for imparting optical properties to the film; a transport mechanism for transporting the aforementioned film; A plurality of position acquisition devices are arranged at a plurality of positions on the conveying mechanism, and continuously obtain the first end and the first end in the width direction of the film being conveyed by the conveying mechanism at the plural positions. The position of the two end portions; and the calculation portion, set the distance between the reference position in the width direction of the film and the position of the first end as the first width, and set the reference position and the second end When the distance of the part is set to the second width, the position of the first end and the second end in the device is obtained based on the two positions selected from the plurality of position obtaining devices. Calculate the aforementioned reference position based on the first obtained result of the first obtained result and the position of the first end and the second end in the downstream position obtaining device of the two position obtaining devices Secondly, the result is obtained, and the difference between the first rate of change of the first width and the second rate of change of the second width is calculated.

In the aforementioned manufacturing method and the aforementioned manufacturing apparatus, the positions of the first end and the second end of the transported film are continuously obtained at a plurality of locations. According to the first acquisition result and the second acquisition result belonging to the acquired results of the two parts (upstream part and downstream part) selected from a plurality of parts, the first change rate and the first change rate of the first width of the film are calculated The difference between the second rate of change of the two widths. Therefore, it is possible to obtain the difference between the aforementioned first rate of change and the second rate of change during transport of the film. Therefore, when the difference between the aforementioned first rate of change and the second rate of change exceeds the allowable range, for example, the production of the optical film may be interrupted or the manufacturing conditions may be adjusted to be within the allowable range to avoid loss. In addition, it can also be managed without exceeding the allowable range, thereby preventing a loss in the first place. As a result, it is not easy to manufacture a defective optical film, and defects such as cutting can be suppressed. Lost. Therefore, the optical film can be manufactured in a stable step. Furthermore, it is possible to uniformly manufacture optical films of stable quality. Furthermore, in addition, the material cost of the optical film can be reduced.

In the aforementioned manufacturing method, the aforementioned reference position in the aforementioned upstream portion may be a central position of the aforementioned film in the aforementioned upstream portion in the width direction.

In the manufacturing apparatus, the reference position in the arrangement part of the upstream position obtaining device may be the center position in the width direction of the film obtained based on the first acquisition result in the arrangement part.

In the aforementioned manufacturing method, the difference between the first rate of change and the second rate of change in at least one combination of the upstream portion and the downstream portion selected from the plurality of portions may be 1.0% or less. Alternatively, in the foregoing manufacturing method, the difference between the first rate of change and the second rate of change in all combinations of the plurality of combinations of the upstream portion and the downstream portion selected from the plurality of portions may be 1.0 %the following.

In the aforementioned manufacturing apparatus, the difference between the first rate of change and the second rate of change in at least one combination of the upstream position obtaining device and the downstream position obtaining device selected from the plurality of position obtaining devices is also It can be 1.0% or less. Or, in the manufacturing device, the first rate of change and the second rate of change in all combinations of the upstream position acquiring device and the downstream position acquiring device selected from the plurality of position acquiring devices The difference in the rate of change may be 1.0% or less.

In the aforementioned manufacturing method, the upstream portion may be a position before one of the N treatments is performed, and the downstream portion may be a position after the one treatment is performed.

In the aforementioned manufacturing apparatus, the upstream position acquiring device may be arranged before one of the N processing sections, and the downstream position acquiring device may be arranged after the one processing section.

The aforementioned first width and the aforementioned second width of the film tend to change when the film is processed. Therefore, in the aforementioned configuration, the difference between the first rate of change and the second rate of change can be calculated at a location where the first width and the second width are easily changed. The first rate of change and the second rate of change can also be calculated.

In the aforementioned manufacturing method, the aforementioned N treatments may include the i-1th treatment, the ith treatment, and the i+1th treatment (i is an integer greater than or equal to 2), and the upstream part is located at the i-1th Between the position of each treatment and the position of the i-th treatment, and the downstream part is between the position of the i-th treatment and the position of the i+1-th treatment.

In the aforementioned manufacturing device, the aforementioned N processing units may include an i-1th processing unit, an i-th processing unit, and an i+1th processing unit (i is an integer greater than or equal to 2), and the upstream position is obtained The device is arranged between the i-1th processing unit and the i-th processing unit, and the downstream position obtaining device is arranged between the i-th processing unit and the i+1th processing unit.

The aforementioned first width and the aforementioned second width of the film tend to change when the film is processed. Therefore, in the aforementioned configuration, the difference between the first rate of change and the second rate of change can be calculated at a location where the first width and the second width are easily changed. Furthermore, in the foregoing configuration, when the difference between the first rate of change and the second rate of change exceeds the allowable range, it can be inferred that the difference between the foregoing difference exceeds the allowable range is due to the i-th process or the i-th process The state of the previous membrane has changed. In the aforementioned configuration, since the reason for the business trip exceeding the allowable range can be easily specified in this way, it is possible to avoid a failure before it occurs.

In the aforementioned manufacturing method, the aforementioned N treatments may include the i-1th treatment and the i-th treatment (i is an integer greater than or equal to 2), and the upstream part is located at the position of the i-1th treatment, Furthermore, the downstream part is between the position of the i-1th treatment and the position of the i-th treatment; the upstream part and the downstream part may be located at the position of the i-1th treatment and the position of the i-1th treatment respectively. i processed Between positions; or, the upstream part may be the position before the i-1th treatment, and the downstream part may be the position in the i-1th treatment.

In the aforementioned manufacturing apparatus, the N processing units may include the i-1th processing unit and the i-th processing unit (i is an integer greater than or equal to 2), and the upstream position acquisition device may be arranged in the i-th The position of one processing unit, and the downstream position acquisition device is arranged between the i-1th processing unit and the i-th processing unit; the upstream position acquisition device and the downstream position acquisition device can also be used The devices are respectively arranged between the i-1th processing section and the i-th processing section; alternatively, the upstream position obtaining device may be arranged before the i-1th processing section, and, The downstream position obtaining device is arranged at the position of the i-1th processing unit.

In the foregoing configuration, the difference between the first rate of change and the second rate of change when the film is processed, or the first rate of change and the second rate of change between the end of one process and the next process for the film can be calculated The difference.

In the aforementioned manufacturing method, during the aforementioned conveying, the image of the first end portion and the second end portion of the film may be acquired by the imaging unit.

In the aforementioned manufacturing device, at least one of the aforementioned plurality of position obtaining devices may have an imaging unit that takes images of at least the first end and the second end of the film.

In this case, the position of the first end and the second end can be calculated using the image obtained through the imaging unit.

In the aforementioned manufacturing method, the positions of the first end and the second end may be obtained based on the brightness of at least one of the reflected light and the transmitted light from the film during the transportation, wherein The reflected light and the penetrating light of the film are caused by the light incident on the film.

In the aforementioned manufacturing device, at least one of the aforementioned plurality of position obtaining devices may also have a light detecting unit that detects at least one of reflected light and transmitted light from the film, wherein The reflected light and the penetrating light are caused by light incident on the film.

In the aforementioned manufacturing apparatus, at least one of the plurality of position obtaining devices may have a light irradiation section that irradiates light to the film. For example, when the difference in brightness between the transmitted light from the film and the light in the surrounding environment is small, the brightness of the surrounding environment can be increased by the light from the light irradiation part. As a result, the positions of the first end and the second end of the film can be easily detected.

In the aforementioned manufacturing method, the film may be transported by a roll, and light is irradiated to the film on the transport roll, and the film and the reflection of the transport roll generated by the irradiated light The difference in the brightness of the light obtains the positions of the first end and the second end.

In the aforementioned manufacturing device, the conveying mechanism may have a conveying roller, the light irradiation section irradiates light to the film on the conveying roller, and at least one of the plurality of position obtaining devices is based on The position of the first end and the second end of the film is obtained by the difference between the brightness of the film and the reflected light of the transport roller caused by the light irradiated from the light irradiating portion to the film on the transport roller.

At this time, it is easy to specify the positions of the first end and the second end of the film by the difference in brightness between the reflected light from the film and the reflected light from the conveying roller. As a result, the difference between the first rate of change and the second rate of change can be calculated more accurately. When the reflected light from the film is regular reflection and has sufficient brightness, the measurement is not limited to the conveying roller.

In the aforementioned manufacturing method, the aforementioned transmitted light may also be transmitted light from the aforementioned film, wherein the aforementioned transmitted light from the aforementioned film is caused by light incident on the aforementioned film through a polarizing filter. By. Alternatively, in the aforementioned manufacturing method, the positions of the first end and the second end of the film can also be obtained based on the brightness of the light obtained by the passing light through the polarizing film.

In one embodiment of the aforementioned manufacturing apparatus, a polarizing filter may be provided between the aforementioned light irradiating part and the aforementioned film. Alternatively, in one embodiment of the aforementioned manufacturing apparatus, a polarizing filter may be provided between the aforementioned light detecting portion and the aforementioned film.

For example, when the film has linear polarization characteristics, the position of the first end and the second end of the film can be easily obtained by disposing the polarizing filter in a crossed nicol state with the film.

In the aforementioned manufacturing method, the aforementioned N treatments may include at least one of swelling treatment, dyeing treatment, stretching treatment, and drying treatment.

In the aforementioned manufacturing apparatus, the aforementioned N processing units may include at least any one of a swelling processing unit, a dyeing processing unit, a cross-linking processing unit, an elongation processing unit, and a drying processing unit.

An example of the aforementioned optical film is a polarizing filter.

According to the present invention, it is possible to provide an optical film manufacturing method and an optical film manufacturing device that can be implemented in stable steps, not only has stable quality, but also reduces material costs.

2: membrane

2a: first end

2b: second end

4: Polarizing film (optical film)

6: Raw material roll

10: Manufacturing device

11, 11 ₁ to 11 ₆ : Roll

12, 12 ₁ to 12 ₁₂ : guide roller

13 ₁ : Swelling treatment part

13 ₂ : Dyeing Department

13 ₃ : Cross-linking treatment section

13 ₄ : Cleaning treatment department

13 ₅ : Drying department

20, 20 ₁ to 20 ₁₂ : Get points (multiple parts)

30: Location acquisition device

30 _UP : Upstream position acquisition device

30 _DOWN : Downstream position acquisition device

31, 31A, 31B: end detector

32: Light Irradiation Department

33, 36: Light detection unit (imaging unit)

34, 35: shell

34a, 35a: window

37: Polarizing filter

40: Calculation Department

B, Bx, By: reference position

R: Conveying roller

W1a, W2a: the first width

W1b, W2b: second width

FIG. 1 is a schematic diagram for explaining a manufacturing method of an optical film of an embodiment.

Figure 2 is a diagram for explaining the change of the film width in the optical film manufacturing method.

Figure 3 is a diagram for explaining the position acquisition device and the calculation unit.

Figure 4 is a diagram for explaining an example of the width detector included in the position obtaining device.

Fig. 5 is a diagram for explaining another example of the width detector included in the position obtaining device.

The following describes the implementation of the present invention with reference to the drawings. In the drawings, the same or equal parts are given the same symbols, and repeated descriptions are omitted. The size ratio of the drawing may not be consistent with the illustrated one.

Figure 1 is a schematic diagram for explaining an embodiment of the present invention. Hereinafter, a case where a polarizing film is manufactured as an optical film will be described as an example.

In this embodiment, while the long film 2 is conveyed, N processing (N is an integer greater than or equal to 1) is sequentially performed on the film 2 being conveyed, thereby manufacturing a polarizing film (optical film) 4. The N treatment systems are treatments for imparting at least linear polarization characteristics as optical characteristics to the film 2. Although the upper limit of N is not particularly limited, N is usually an integer of 30 or less, and it may be an integer of 25 or less, or an integer of 20 or less, or an integer of 10 or less.

When the film 2 is given linear polarization characteristics, the film 2 functions as the polarizing film 4. The linear polarization characteristic is substantially imparted before the N processes are completed. Therefore, in the manufacturing method of the polarizing film 4 using the film 2, the film 2 functions as the polarizing film 4 during the manufacturing process. However, for ease of description, unless otherwise stated, the film 2 after the N processes are all finished is called the polarizing film 4, and the film before the N processes are all called the film 2. When manufacturing the polarizing film 4, usually, the film 2 is subjected to swelling treatment, dyeing treatment, cross-linking treatment, stretching treatment, and drying treatment. The stretching treatment may be performed on the film 2 in any one treatment (for example, a crosslinking treatment), or may be performed on the film 2 while performing a plurality of treatments.

The film 2 is a polyvinyl alcohol (polyvinyl alcohol) resin film. An example of the length of the film 2 in the longitudinal direction is 1000 m or more and 30000 m or less, preferably in the range of 1000 m or more and 20000 m or less. An example of the length of the film 2 in the width direction (the direction orthogonal to the longitudinal direction) is 1300 mm to 5000 mm. An example of the thickness of the film 2 before being subjected to N treatments is 10 μm to 100 μm. The film 2 can be produced by a known method such as a melt extrusion method and a solvent casting method. The film 2 may be a purchased film or a film that has been processed in advance such as stretching or lamination. In the case shown in FIG. 1, the film 2 is prepared as the raw material roll 6, and N treatments are performed on the film 2 drawn from the raw material roll 6 to obtain the polarizing film 4. When the film 2 is manufactured by the aforementioned method (melt extrusion method, solvent casting method, etc.), for example, the film 2 manufactured by the aforementioned method (melt extrusion method, solvent casting method, etc.) may be continuously conveyed, and In this conveyance, the aforementioned N processes are performed.

The manufacturing device 10 of the polarizing film 4 is provided with: a plurality of nip rolls 11; a plurality of guide rolls 12; a swelling treatment part 13 ₁ ; a dyeing treatment part 13 ₂ ; a cross-linking treatment part 13 ₃ ; a cleaning treatment Section 13 ₄ ; and drying treatment section 13 ₅ .

The plural rollers 11 and the plural guide rollers 12 are conveying rollers included in the conveying mechanism of the film 2 and used for conveying the film 2. By appropriately arranging a plurality of rolls 11 and a plurality of guide rolls 12, a transport path of the film 2 is constituted.

The roll 11 has a function of pinching and pressing the film 2 to impart the rotational force of the roll 11 to the film 2. The roll 11 also has a function of changing the conveying direction of the film 2. In the transport direction of the film 2, for example, by providing a peripheral speed difference between two adjacent rolls 11, the film 2 transported between the two adjacent rolls 11 is subjected to a stretching process (for example, a uniaxial stretching process). FIG. 1 illustrates a case where the manufacturing apparatus 10 has six rolls 11. When the six rolls 11 are described separately, as shown in Fig. 1, the six rolls 11 are referred to as rolls 11 ₁ to 11 ₆ .

The guide roller 12 has a function of supporting the film 2 and changing the conveying direction of the film 2. Fig. 1 illustrates a case where the manufacturing apparatus 10 has 12 guide rollers 12. When the 12 guide rollers 12 are described separately, as shown in Fig. 1, the 12 guide rollers 12 are referred to as guide rollers 12 ₁ to 12 ₁₂ .

The swelling treatment part 13 ₁ is a part that performs the swelling treatment on the film 2. Swelling treatment system having a processing unit ₁₃₁ for processing liquid storage tank swelling treatment of the used. 2 by the membrane was immersed in _a treatment solution 13 having a swelling treatment unit, the swelling treatment is performed to the film 2. In this embodiment the patterns, based roll ₁₁₁ by the guide roll 121 _to 123 and ₁₂₃ to form a film 2 To transport path immersed in the liquid of the treated film. In this configuration, the roller ₁₁₁ and the guide roller ₁₂₃ arranged based on swellable by processing unit ₁₃₁ to the film 2 before and after the swelling treatment purposes (in other words, before ₁₃₁ and after the swelling treatment system unit).

The aforementioned swelling treatment is performed for the purpose of removing foreign matter on the surface of the film 2, removing the plasticizer in the film 2, imparting easy dyeability in a subsequent step, and plasticizing the film 2. The conditions of the swelling treatment can be determined within the range that can achieve these purposes, and within the range that does not cause the extreme dissolution and devitrification of the membrane 2. _131, the example 2 based film by immersing the temperature of 10 to 50 ℃, preferably to the processing solution 20 to 50 deg.] C the swelling portion swelling treatment process. The swelling treatment time is about 5 to 300 seconds, preferably about 20 to 240 seconds. Example 13 ₁ of the treatment liquid in the processing unit is water swellable. Therefore, the swelling treatment can also serve as the water washing treatment of the membrane 2.

Dyeing unit ₁₃₂ based partial dyeing process to the film 2. Dyeing unit ₁₃₂ includes a processing system for processing liquid storage tank used in the process of dyeing. The film ₂ is dyed by immersing the film in the treatment liquid contained in the dyeing treatment section 132. In the present embodiment patterns, the system ₁₁₂ by the roll and the guide rollers 12 _{4-12 6} To form a film 2 was immersed in the treatment liquid transport path of the film. In this configuration, the roller ₁₁₂ and the guide roller ₁₂₆ arranged in lines by coloring treatment section ₁₃₂ for the purposes of the film 2 and then (in other words, _two lines before and after the coloring treatment unit 13) before the dyeing treatment.

Processing liquid system ₁₃₂ of the present embodiment has the processing patterns in the stained portion of an aqueous solution of dichroic dye in the dyeing process, dye-based to dichroic film 2 for staining. Generally, the dyeing process by a dichroic dye is performed for the purpose of adsorbing the dichroic dye to the film 2 and the like. The processing conditions are within the range that can achieve this purpose, and within the range that does not cause defects such as extreme dissolution and devitrification of the film 2, and are determined according to the desired optical characteristics. Examples of dichroic dyes used in dyeing are iodine and dichroic dyes.

When iodine is used as a dichroic dye, it is, for example, at a temperature of 10 to 50°C, preferably 15 to 40°C, and contains 0.003 to 0.2 parts by weight of iodine and 0.1 to 10 parts by weight relative to 100 parts by weight of water. The film 2 is immersed in the aqueous potassium iodide solution for 10 to 600 seconds, preferably 30 to 300 seconds, thereby performing a dyeing process. Other iodides such as zinc iodide can also be used instead of potassium iodide. Other iodides and potassium iodide can also be used in combination. Furthermore, compounds other than iodide, for example, boric acid, zinc chloride, cobalt chloride, etc. may coexist. If it is a treatment liquid containing 0.003 parts by weight or more of iodine with respect to 100 parts by weight of water, it can be regarded as a treatment liquid for dyeing.

When a water-soluble dichroic dye is used as a dichroic dye, it is, for example, at a temperature of 20 to 80°C, preferably 30 to 60°C, and contains 0.001 to 0.1 parts by weight relative to 100 parts by weight of water. The film 2 is immersed in the aqueous solution of the color dye for 10 to 600 seconds, preferably 20 to 300 seconds, thereby performing a dyeing process. The aqueous solution of the dichroic dye used may also contain dyeing auxiliary agents, etc., and may also contain inorganic salts such as sodium sulfate and surfactants. Only one type of dichroic dye may be used, or two or more types of dichroic dyes may be used in combination depending on the desired hue.

Crosslinking treatment section ₁₃₃ is based crosslinking treatment to the film portion 2. Crosslinking treatment system having storage unit ₁₃₃ for cross-linking treatment with the treatment liquid in the treatment tank. By treatment liquid film was immersed in a crosslinking processing section ₁₃₃ has, and the crosslinking treatment to the film 2. In this embodiment the patterns, based by the guide rollers ₁₁₃ and rollers 12 _{7-12 9} To form a film transport path 2 is immersed in liquid of the treated film. In this configuration, the roller ₁₁₃ and the guide roller ₁₂₉ arranged in line by crosslinking treatment section ₁₃₃ for the purposes of the film 2 before and after the crosslinking process (in other words, after the crosslinking treatment section ₃ and line 13 before the post).

The cross-linking treatment is a treatment performed for the purpose of water resistance and hue adjustment (preventing the film 2 from being bluish, etc.) by cross-linking.

Treatment liquid ₁₃₃ used crosslinking treatment unit, based, for example, with respect to 100 parts by weight of water an aqueous solution containing boric acid, for example, from about 10 to 1 part by weight of. When the treatment liquid dichroic dye used in the dyeing process is iodine, crosslinking treatment unit ₁₃₃ is used, the addition of boric acid is preferably further contains an iodide, the content thereof with respect to 100 parts by weight based water e.g. 1 to 30 parts by weight. In terms of iodide, there are, for example, potassium iodide, zinc iodide, and the like. Compounds other than iodide, for example, zinc chloride, cobalt chloride, zirconium chloride, sodium thiosulfate, potassium sulfite, sodium sulfate, etc. may coexist.

In the crosslinking treatment crosslinking treatment section _133, the system may be depending on the purpose, and suitably changed iodide concentration of boric acid, and the processing temperature of the liquid.

For example, when the purpose of the cross-linking treatment is water resistance by cross-linking, and the polyvinyl alcohol-based resin film is subjected to swelling treatment, dyeing treatment, and cross-linking treatment in order, the cross-linking agent of the treatment liquid contains liquid, It is, for example, an aqueous solution whose concentration is boric acid/iodide/water=3 to 10/1 to 20/100 in terms of weight ratio. If necessary, other crosslinking agents such as glyoxal or glutaraldehyde can also be used to replace boric acid, and boric acid and other crosslinking agents can also be used in combination. The temperature of the treatment liquid when immersing the film 2 is usually about 50°C to 70°C, preferably about 53°C to 65°C. The immersion time of the film 2 is usually about 10 to 600 seconds, preferably 20 to 300 seconds. More preferably, it is 20 to 200 seconds. When the film 2 pre-stretched before the swelling treatment is to be sequentially dyed and cross-linked, the temperature of the treatment liquid is usually 50 to 85°C, preferably 55 to 80°C.

The purpose of the cross-linking treatment is to adjust the hue. For example, when iodine is used as a dichroic pigment, it is possible to use a cross-linking agent containing liquid with a concentration by weight ratio of boric acid/iodide/water=1 to 5/3 to 30/100 As a treatment liquid. The temperature of the treatment liquid when the membrane 2 is immersed is usually about 10 to 45°C, and the immersion time of the membrane 2 is usually about 1 to 300 seconds, preferably 2 to 100 seconds.

_134-based cleaning process for the cleaning of the film after the crosslinking treatment unit 2 is part of the processing. Cleaning tank for cleaning the reservoir with the liquid treatment system having a processing unit _134. 2 by the membrane was immersed in cleaning liquid processing section ₁₃₄ has in order to perform cleaning treatment to the film 2. In this embodiment the patterns, based by the guide rollers ₁₁₄ and rollers 12 _{10-12 12} To form a film transport path 2 is immersed in liquid of the treated film. In this configuration, the roller ₁₁₄ and the guide roller ₁₂₁₂ by lines disposed in the cleaning process unit ₁₃₄ for the purposes of the film 2 before and after the cleaning process (in other words, after the processing unit ₄ based cleaning before and 13). The treatment liquid in the cleaning treatment includes, for example, water, an aqueous solution containing potassium iodide, and an aqueous solution containing boric acid. The temperature of the treatment liquid is usually about 2°C to 40°C, and the treatment time is usually about 2 seconds to 120 seconds.

Cleaning process in the cleaning process unit _134, the treatment liquid may by spray (shower) method of embodiment sprayed or impregnated with a spray and a method for cleaning the membrane 2.

Drying processing unit ₁₃₅ based partially drying treatment to the film 2. In the present embodiment patterns, the drying system for the processing unit ₁₃₅ drying apparatus. For the drying process unit ₁₃₅ has been moved into the cleaning process unit ₁₃₄ through the cleaning process of the film 2, 2 through the membrane during the drying process section ₁₃₅ of the membrane 2 was dried. In the present embodiment patterns, the system by rollers _{115, 116} to form a film 2 To transport path immersed in the liquid of the treated film. In the drying section _135, also suitably arranged guide rollers 12, to support and transport the film 2. By drying unit drying process performed _135, based in the drying section is maintained at a temperature of about 40 ℃ deg.] C to 100 of the _135, for about 30 seconds to about 600 seconds. In Fig. 1, the drying treatment section 13 ₅ is schematically shown. If the drying process unit ₁₃₅ can be attached to a water content of dried film 2 is not particularly limited, and may be those known in the manufacture of a polarizing film is generally used.

In the manufacturing apparatus 10, a stretching process is performed. The stretching process utilizes the difference in peripheral speed of at least two of the plurality of rolls 11 (the upstream roll 11 and the downstream roll 11) to uniaxially stretch the film 2 deal with. At this time, the two rolls 11 that contribute to the aforementioned uniaxial stretching process function as a stretching process part.

For example, also extends process, the extension processing using the configuration to the roll ₍₃₎ before 13 crosslinked portion ₁₁₃ and arranged in the circumferential speed difference crosslinking unit rolled after the ₁₃₃ roller ₁₁₄ while performing a shaft extension process. In this case, the processing line extends simultaneously with crosslinking, thus crosslinking treatment section ₁₃₃ also functions as a processing unit of the extensions. Stretching treatment is also effective in suppressing wrinkles.

The stretching treatment may be performed mainly by using two rolls 11 arranged before and after one treatment section (for example, the aforementioned cross-linking treatment section 13 ₃ ), on the other hand, the stretching treatment may be gradually performed by other rolls 11.

The manufacturing apparatus 10 may additionally have an extension processing part for performing extension processing. In this case, the extension processing unit arranged in lines such as posterior segment (e.g., cross-linking between the processing unit ₁₃₃ and the cleaning process unit ₁₃₄₎ crosslinking treatment section ₁₃₃ is.

A plurality of manufacturing apparatus 10 can also be a swelling process unit _131, processing unit ₁₃₂ dyeing, crosslinking treatment section _133, the cleaning portion of at least one processing unit ₁₃₄ processing unit ₁₃₅ and the drying process has a. For example, the manufacturing apparatus 10 may include a plurality of cross-linking processing units 13 ₃ . The same is true for the case where the manufacturing apparatus 10 includes the stretching processing section, and the manufacturing apparatus 10 may include, for example, a plurality of stretching processing sections.

When the polarizing film 4 is manufactured using the aforementioned manufacturing apparatus 10, first, the film 2 is drawn out from the raw material roll 6, and the film 2 is moved in the longitudinal direction along a conveying path formed by a plurality of rolls 11 and a plurality of guide rolls 12. Transport. For example, the conveying speed can be 1m/min to 60m/min, or 1.5m/min to 50m/min. 2 in the film conveyance path, line 6 from the stock roll from the side provided with the swelling process unit _131, processing unit ₁₃₂ dyeing, crosslinking treatment unit _133, cleaning unit ₁₃₄ and the drying process unit _135. Furthermore, as mentioned above, at least two rolls 11 also have a function as a stretching processing part. Therefore, the transported film 2 is subjected to swelling treatment, dyeing treatment, cross-linking treatment, washing treatment, and drying treatment, and also to stretching treatment. By this, linear polarization characteristics (optical characteristics) are imparted to the film 2 to obtain the polarizing film 4.

After drying the polarizing film obtained by the processing unit ₁₃₅ 4, for example based on producing a polarizing film comprising the polarizing plate 4. For example, the aforementioned polarizing plate can be manufactured by performing a bonding step, etc., in which a protective film is bonded to one side or both sides of the polarizing film 4. After drying the polarizing film obtained by processing unit _1354, the transport system can be continuously manufactured in the polarizing plate can also be temporarily wound into a roll.

As shown in Fig. 2, in the process of manufacturing the polarizing film 4 by performing N processes on one side of the film 2 being transported, the length of the film 2 in the width direction changes. At this time, the rate of change of the first width between the reference position B of the film 2 in the width direction of the film 2 and the first end 2a of the film 2 (hereinafter referred to as the "first narrowing rate"), and The rate of change of the second width between the aforementioned reference position and the second end 2b of the film 2 (hereinafter referred to as the "second narrowing rate") may be different.

Hereinafter, the part located on the upstream side of any two parts in the transport of the membrane 2 is called the upstream part, and the part located on the other downstream side of the upstream part is called the downstream part. The reference position B of the aforementioned film 2 is set so that the straight line connecting the reference position Bx located at the upstream portion and the reference position By located at the downstream portion becomes a straight line parallel to the transport direction of the film 2.

An example of the reference position Bx is the center position in the width direction of the film 2 in the upstream part.

The first width (the distance between the reference position B and the first end 2a) in the upstream part is W1a, and the second width (the distance between the reference position B and the second end 2b) is W1b, Before the downstream part The first width is set to W2a, and the second width is set to W2b. When the first narrowing rate (%) of the first width and the second narrowing rate (%) of the second width between the upstream part and the downstream part are set to α (%) and β (%), the first When the difference (%) between the narrowing rate and the second narrowing rate is γ (%), in the present embodiment, α, β, and γ are defined as follows.

α=[(W1a-W2a)/W1a]×100...(1)

β=[(W1b-W2b)/W1b]×100...(2)

γ=｜α-β｜...(3)

In one embodiment of the present invention, there is a monitoring step of monitoring the difference γ between the aforementioned first narrowing rate (first rate of change) α and the second narrowing rate (second rate of change) β. In the monitoring step, as shown in Figure 1, the positions of the first end 2a and the second end 2b of the film 2 are continuously obtained by a plurality of acquisition points 20 (a plurality of locations) in the film 2 being transported (Hereinafter also referred to as "both ends"). In Fig. 1, a plurality of obtained points 20 are shown with arrows. When the plural acquisition points 20 are described separately, the plural acquisition points 20 are referred to as acquisition points 20 ₁ to 20 ₁₂ .

The acquisition point 20 may also be the point at which the two ends of the film 2 wound on the roll 11 or the guide roll 12 are obtained, or it may also be the point at which the two ends of the film 2 not wound on the roll 11 or the guide roll 12 are acquired. Point of location. The acquisition point 20 shown in Figure 1 is an example. For example, the acquisition point 20 ₁ may also be a point for acquiring the positions of the two ends of the film 2 sent from the roll 11 ₁ and the acquisition point 20 ₄ may also be the acquisition of the wound ₁₂₆ of the film guide roll 2 (upper film guide roll ₁₂₆ 2) of the end positions of the points.

The dyeing process is performed at the acquisition points 20 ₁ to 20 ₃ before the film 2, preferably the points at both ends of the film 2 wound around the roller 11 or the guide roller 12. On the other hand, after acquisition point _204, the relationship between the roll 11 or 12 and the film guide rollers 2, normally not defined.

The acquisition point 20 may be arranged, for example, where one of the N processes is performed before and after the film 2. For example, the acquisition point 201 is a point at which both ends of the film 2 in the state wound around the roll 11 ₁ or just after being sent out from the roll 11 ₁ in Figure ₁ are acquired, and is the acquisition point before the swelling treatment is performed. Point ₂₀₂ is made based on the guide roller ₁₂₃ to obtain or just after the guide ₁₂₃ feeding points at both ends of the film roll 2 position.

Therefore, the acquisition points 20 ₁ and 20 ₂ are points for acquiring the positions of both ends of the film 2 before and after the film 2 is subjected to the swelling treatment. In this way, the acquisition points before and after the treatment (before and after the film is immersed in the treatment liquid of a certain treatment part) are also the acquisition points before and after the treatment part where the treatment is performed.

Another example of obtaining points 20 is to obtain points 20 ₃ , 20 ₄ , obtain points 20 ₅ , 20 ₇ , obtain points 20 ₈ , 20 ₁₀ , and obtain points 20 ₁₁ , 20 ₁₂ . Acquisition points 20 ₃ , 20 ₄ , acquisition points 20 ₅ , 20 _7, and acquisition points 20 ₈ , 20 ₁₀ are used to acquire the positions of both ends of the film 2 before and after the swelling treatment, dyeing treatment, cross-linking treatment, and cleaning treatment point. The acquisition points 20 ₁₁ and 20 ₁₂ are points for acquiring the positions of the two ends of the film 2 before and after the drying process.

The acquisition point 20 may also be a point for acquiring the positions of the first end portion 2a and the second end portion 2b of the film 2 during a step in which a process is performed on the film 2. Such an example of obtaining points 20 is to obtain points 20 ₆ and 20 ₉ . Acquisition system ₂₀₆ is a point between the guide rollers ₁₂₇ and the guide roller ₁₂₈ of the transfer film 2 on the way of acquisition points. Similarly, to obtain ₂₀₉ lines to obtain the point to point transfer roller 12 between the guide ₁₀ and the guide roller ₁₂₁₁ to send the film 2 on the way. At the acquisition points 20 ₆ and 20 ₉ , the positions of the two ends of the film 2 in the treatment liquid are acquired.

In the monitoring step, among the two locations selected in advance from the plurality of acquisition points 20, the location of the first end portion 2a and the second end portion 2b of the film 2 in the upstream portion is obtained based on the obtained results (hereinafter referred to as " The first obtained result”), and the obtained results of the positions of the first end 2a and the second end 2b of the film 2 in the downstream part (hereinafter referred to as the “second obtained result”) to calculate the first narrowing rate α The difference γ from the second narrowing rate β. The first and second obtained results may also be, for example, the results obtained at the same point in time (that is, at the same time) of the upstream and downstream parts (that is, the two points may also be measured at the same point in time ( Upstream and downstream parts)). "Same time point (that is, at the same time)" can also be used without departing from the spirit of the present invention There are some deviations within the range. The time difference between the measurement at the upstream part and the measurement at the downstream part is not particularly limited, but it can be within about one minute, within 30 seconds, within 20 seconds, or 10 seconds. Within. The monitoring step is preferably implemented in an automation manner.

In the example of the aforementioned upstream part and downstream part, the upstream part is before one of the N treatments (hereinafter referred to as "scheduled treatment"), and the downstream part is after the aforementioned scheduled treatment. For example, when the aforementioned predetermined treatment is set as the dyeing treatment, the upstream part is before the dyeing treatment, and the downstream part is after the dyeing treatment. The so-called "before the scheduled treatment" and "after the scheduled treatment" also include cases where other treatments are performed between the upstream part and the downstream part and the aforementioned "scheduled treatment".

When two adjacent processes among N processes are called the i-1th process and the i-th process (i is an integer greater than or equal to 2), and the corresponding processing part is called the i-1th process part In the case of the i-th treatment section, the upstream part and the downstream part may be any of the following arrangement examples 1 to 3.

In this specification, the upper limit of i is not particularly limited, but i is usually an integer of 30 or less, or an integer of 25 or less, or an integer of 20 or less, or an integer of 10 or less.

[Configuration example 1]

The upstream part is located at the position of the i-1th treatment (the position of the i-1th treatment part), and the downstream part is at the position of the i-1th treatment (the i-1th treatment part) and the i-th Between the positions of the processing (i-th processing section). For example, when the first process is the i-1 th crosslinking treatment, a plurality of the first acquisition shown in FIG point 20, for example, the upstream portion and downstream portion, the line ₆ and the point 20 to obtain ₂₀₇ points acquired.

[Configuration example 2]

The upstream part and the downstream part are respectively between the position of the i-1th treatment (i-1th treatment part) and the position of the i-th treatment (ith treatment part). For example, when the first process is the i-1 th crosslinking treatment, a plurality of the first acquisition shown in FIG point 20, for example, the upstream portion and downstream portion, the line ₂₀₇ and the acquired points acquired point _208.

[Configuration example 3]

The upstream part is the position before the i-1th treatment (i-1th treatment part), and the downstream part is the position in the i-1th treatment (the position of the i-1th treatment part). For example, when the i-1th process is a cross-linking process, among the plural acquisition points 20 shown in Fig. 1, the upstream part and the downstream part are the acquisition point 20 ₅ and the acquisition point 20 ₆ .

When i is an integer greater than or equal to 2, the next process of the i-th process is called the i+1th process, and the corresponding process part is called the i+1th process part, the upstream part and the downstream part An example may also be the following configuration example 4.

[Configuration example 4]

The upstream part is between the position of the i-1th treatment (i-1th treatment part) and the position of the i-th treatment (i-th treatment part), and the downstream part is in the i-th treatment (ith Between the position of the processing unit) and the position of the i+1th processing (i+1th processing unit). For example, when the first process is the i-1 th crosslinking treatment, a plurality of the first acquisition shown in FIG point 20, for example, the upstream portion and downstream portion, the line ₂₀₇ and the acquired points acquired point _2010.

For example, also be made as a point upstream portion ₂₀₁ and downstream portion ₂₀₈ is made of the way point, using a combination of non-adjacent two points to obtain 20 as a combination of an upstream portion and a downstream portion.

When plural number _131, a dyeing treatment section _132, a crosslinking treatment section _133, cleaning _134, at least one processing unit drying unit ₁₃₅ in the processing unit, an upstream portion and a downstream portion of a swelling treatment unit manufacturing apparatus 10 having Each may be a part where the treatment for the same purpose is performed, or it may be a part where the treatment for a different purpose is performed. For example, when the manufacturing apparatus 10 has two or more swelling treatment parts 13 ₁ , and the two swelling treatment parts 13 _{1 are} called swelling treatment parts 13 ₁ -a and 13 ₁ -b, the upstream part may be the swelling treatment part 13 The position of _1- a (or before or after it), and the downstream part is the position of the swelling treatment part 13 ₁ -b (or before or after it), and the upstream part may be the swelling treatment part 13 ₁ -a position or swollen processing unit 13 ₁ -b (or its front or rear), and for the location of the downstream portion ₁₃₂ of the staining process unit (or front or back). The same is true when there are a plurality of extension processing parts.

The difference γ between the first narrowing rate α and the second narrowing rate β can also be calculated separately by a plurality of combinations of the upstream part and the downstream part selected from the plural acquisition points 20. For example, according to the results achieved in obtaining the point ₂₀₁ and point 20 the results achieved in obtaining calculated difference γ ₂ a first width shrinkage rate of α and β of the second neck, and made in accordance with the outcome of the points ₂₀₅ the results achieved in obtaining the point ₂₀₇ and the calculating a difference γ. Among the plural combinations of the upstream part and the downstream part, the upstream part and the downstream part may be a common combination. For example, the operator may be achieved according to the outcome of the point ₂₀₁ and the point 20 the outcome of obtaining travel gamma] _2, and results obtained made in accordance with the results achieved point ₂₀₁ and point ₂₀₄ is acquired and calculates a difference γ. Similarly, also made in accordance with the outcome of the point ₂₀₅ and point ₂₀₇ to obtain the outcome of the gamma] and calculates a difference, and the results based on the acquired points ₂₀₆ acquired with the acquisition of the outcome of the point ₂₀₇ calculates a difference γ.

In order to calculate the aforementioned difference γ, as shown in FIG. 3, the optical film manufacturing apparatus 10 has a plurality of position acquisition devices 30 and a calculation unit 40.

Each position obtaining device 30 is a device that continuously obtains the positions of the first end 2a and the second end 2b of the film 2. The plurality of position acquisition devices 30 are arranged at the plurality of acquisition points 20 one to one. That is, one position obtaining device 30 is arranged at one obtaining point 20. In Fig. 3, it is schematically shown that the two position obtaining devices 30 selected for calculating the difference γ among the plurality of position obtaining devices 30 (that is, the upstream position obtaining device 30 disposed at the upstream position _UP , the downstream position acquisition device 30 _DOWN ) arranged in the downstream part, and the calculation unit 40.

The position acquisition device 30 has two end detectors 31. One of the two end detectors 31 is a detector that detects the first end 2a, and the other is a detector that detects the second end 2b. The position acquisition device 30 is configured to detect the first end portion 2a of the film 2 and the state of the film 2 in the acquisition point 20 The second end 2b. Therefore, the structure of the position obtaining device 30 may also be different for each obtaining point 20. However, the configuration of the two end detectors 31 (the two end detectors 31 arranged at one acquisition point 20) included in one position acquisition device 30 is the same.

FIG. 4 is a schematic diagram for explaining the schematic configuration of the end detector 31A which is an example of the end detector 31. The end detector 31A is a detector used when obtaining the positions of the first end 2a and the second end 2b of the film 2 on the transport roller R. The conveying roll R is the roll 11 or the guide roll 12 shown in FIG. 1.

Two end detectors 31A are arranged on the film 2 to detect the first end 2a and the second end 2b respectively. However, as described above, since the end detector 31A has the same configuration, the case where the end detector 31A detects the first end 2a will be described.

The end detector 31A has a light irradiation unit 32 and a light detection unit 33. In FIG. 4, the case where the film 2 is arrange|positioned on the conveyance roller R is illustrated.

The light irradiation part 32 irradiates light toward the film 2. The light irradiating portion 32 is configured to irradiate light toward the outside of the first end portion 2a of the film 2. Therefore, as shown in FIG. 4, when the film 2 is arranged on the transport roller R, the light from the light irradiating section 32 also irradiates the portion of the transport roller R that does not overlap with the film 2. The light irradiation part 32 may be a linear light source extending in the width direction of the film 2. The light irradiation part 32 may have an LED (Light Emitting Diode), for example.

The light irradiation part 32 may also be arranged in the housing 34. The housing 34 has a window portion 34 a for irradiating the film 2 with light output from the light irradiation portion 32. The window portion 34a may be made of a material through which the light output from the light irradiation portion 32 can penetrate. For example, examples of the material of the window portion 34a include polycarbonate resin, acrylic resin, vinyl chloride resin, polypropylene resin, and polyethylene terephthalate. Resin and glass.

The light detection unit 33 detects the brightness of light (reflected light) reflected by the film 2 by the light irradiated from the light irradiation unit 32 to the film 2. The light detecting section 33 may be a camera such as a camera (for example, a CCD (Charge-Coupled Device) camera) that photographs at least the first end 2a of the film 2. As shown in FIG. 4, when the film 2 is arranged on the conveying roller R, the light detecting unit 33 also detects the brightness of the light reflected from the conveying roller R among the light irradiated from the light irradiating unit 32 to the film 2.

The light detection unit 33 is arranged in the housing 35. The housing 35 has a window portion 35 a for detecting the aforementioned reflected light by the light detecting portion 33. The window 35a may be made of a material through which the aforementioned reflected light can penetrate. The example of the material of the window 35a is the same as that of the window 34a.

The dyeing process is performed at the acquisition points 20 ₁ , 20 ₂ , and 20 ₃ before the film 2, usually the points at which the positions of the first end 2a and the second end 2b of the film 2 on the transport roller R are obtained. Therefore, the end detector 31A is suitably applied to the acquisition points 20 ₁ , 20 ₂ , and 20 ₃ .

FIG. 5 is a schematic diagram for explaining the schematic configuration of the end detector 31B which is another example of the end detector 31. The end detector 31B is a detector suitable for the case where linear polarization characteristics are generated in the film 2 (the case where an absorption axis is formed). Typically, line end detector 31B can be applied after dyeing processing unit ₁₃₂ are performed dyeing treatment film 2.

Two end detectors 31B are arranged on the film 2 to detect the first end 2a and the second end 2b, respectively. However, as described above, since the end detector 31B has the same configuration, the case where the end detector 31B detects the first end 2a will be described.

The end detector 31B has a light detection unit 36 and a polarization filter 37.

The light detecting section 36 detects the brightness of the light from the surrounding environment of the film 2 entering the film 2 and passing through the film 2 (hereinafter referred to as "light from the film 2"). The light detecting part 36 may be an imaging part such as a camera (for example, a CCD camera) that photographs at least the first end portion 2a of the film 2.

The aforementioned "light from the surrounding environment of the film 2" includes the illuminating light from the lighting equipment installed in the factory where the polarizing film 4 is manufactured, and the aforementioned illuminating light reflected to the elements constituting the manufacturing device 10 (such as the roll 11 and the guide roller). At least one of the side wall and the bottom wall of the processing tank of each processing unit shown in Fig. 1, the floor of the aforementioned factory, etc.) light. In Figure 5, the light in the surrounding environment of the film 2 is schematically shown with an inverted white arrow.

The polarization filter 37 is a filter having linear polarization characteristics. The polarizing filter 37 is arranged so that the absorption axis of the film 2 and the absorption axis of the polarizing filter 37 are in a cross-Nicol state between the light detecting portion 36 and the film 2. The aforementioned cross-Nicol state is not limited to the case where the angle formed by the absorption axis of the film 2 and the absorption axis of the polarizing filter 37 is 90 degrees, and includes, for example, ±5 degrees, ±10 relative to 90 degrees. The meaning of an error of about 15 degrees or 15 degrees.

The light detection unit 36 and the polarization filter 37 can be arranged in the housing 35 having the window portion 35a in the same manner as the light detection unit 33. The window 35a may be a material that allows light from the film 2 to pass through.

In the case of using only the light of the surrounding environment of the film 2, when the difference in brightness between the light from the surrounding environment detected by the light detecting portion 36 and the light penetrating the film 2 is small, the end detector 31B may also have Auxiliary lighting unit (light irradiation unit). The configuration of the auxiliary lighting unit may be the same as that of the light irradiation unit 32. The auxiliary illuminating unit may be configured to output light that is smaller than the light irradiation unit 32 or has a smaller energy than the power of the light output from the light irradiation unit 32. The auxiliary illuminating unit may be arranged in the housing 34 having the window portion 34a, as in the case of the light irradiation unit 32. The auxiliary illuminating unit is arranged to illuminate at least one of the detection area (or imaging area) of the light detection unit 33 and its periphery, and the light from the auxiliary illuminating unit is incident on the film 2 as light from the surrounding environment.

The end detector 31B can also be used to detect the first end 2a of the film 2 on the transport roller R. The end detector 31B can be used at the acquisition points 20 ₅ , 20 ₈ , and 20 _{10, for} example. The transport roller R at this time is preferably a white roller in order to clarify the difference in brightness.

The end detector 31B can also be used to detect the first end 2a of the film 2 between the transport roller R and the transport roller R. The end detector 31B can be used to detect the first end 2a in the acquisition points 20 ₄ , 20 ₆ , 20 ₇ , 20 ₉ , 20 ₁₁ , and 20 ₁₂ , for example. At this time, a white plate-shaped member or the like may be provided on the background of the detection area of the light detection unit 33 (or the background of the imaging area) to clarify the difference in brightness. In the detection of the first end 2a of the film 2 between the two conveying rollers R, when an auxiliary lighting unit is used, the auxiliary lighting unit can be arranged on the same side of the film 2 as the end detector 31B, also It can be arranged on the side opposite to the end detector 31B with respect to the film 2.

When obtaining points _{206, 209} detecting a first end portion 2a, line end detector 31B obtains the position of the first portion 2a of the terminal 2 of the treatment liquid film. At this time, for example, as shown in FIG. 5, the end detector 31B may include a housing 35 having a window 35a, and the housing 35 may be arranged such that a part of the window 35a is located in the processing liquid. When the part of the window 35a is arranged in the treatment liquid, the outer surface of the window 35a may be subjected to at least one of hydrophilic treatment, uneven processing, and inclined processing. Thereby, air bubbles are less likely to stay on, for example, the outer surface of the window 35a, and therefore it is easy to accurately detect the first end 2a. In the acquisition of the first end portion 2a in the treatment liquid, when an auxiliary illuminating part is used, for example, the auxiliary illuminating part may also illuminate the bottom wall of the treatment tank where the film 2 is processed. At this time, the brightness of the penetrating light irradiated from the auxiliary illuminating unit, reflected on the bottom wall of the processing tank and penetrating through the film 2 is detected by the light detecting unit 36 via the polarization filter 37.

The polarization filter 37 included in the end detector 31B may be arranged on the incident side of the film 2 where light enters, for example. For example, when the end detector 31B has an auxiliary illumination part (light irradiation part), the polarization filter The waver 37 is arranged between the auxiliary illuminating part and the film 2 instead of between the light detecting part 36 and the film 2. At this time, the polarizing filter 37 may also be arranged in a cross-Nicol state with the film 2.

The calculation unit 40 shown in FIGS. 3 to 5 is connected to a plurality of position acquisition devices 30 (position acquisition devices 30 arranged in the upstream and downstream positions) in a wired or wireless manner, and is based on the acquisition from the plurality of positions The obtained result obtained by the device 30 calculates the aforementioned difference γ.

Specifically, the calculation unit 40 determines the film 2 in the placement position of each position obtaining device 30 based on the data obtained by the plurality of position obtaining devices 30 respectively by the end detector 31A (or the end detector 31B) The first end 2a and the second end 2b. The first end portion 2a and the second end portion 2b can be determined by the change of the brightness data belonging to the obtained result of the position obtaining device 30.

For example, as shown in FIG. 4, when the position acquisition device 30 including the end detector 31A detects the first end 2a and the second end 2b of the film 2 on the transport roller R, At this time, the light detecting unit 33 detects the brightness of the reflected light from the film 2 and the reflected light from the transport roller R. Since the brightness of the reflected light from the film 2 and the brightness of the reflected light from the conveying roller R are different, the calculation unit 40 only needs to determine the difference between the first end 2a and the second end of the film 2 2b is fine.

For example, as shown in Figure 5, when the first end 2a and the second end 2b are detected by the position acquisition device 30 including the end detector 31B, the polarizing filter 37 and the film 2 are crossed Nicolas Therefore, the light from the film 2 is substantially blocked, and on the other hand, light from outside the film 2 is detected. Therefore, in the image formed by the brightness data detected by the light detecting section 36, there will be a difference in brightness between the film 2 and the parts other than the film 2 (the film 2 side is darker and the film 2 is brighter), so the calculation The portion 40 only needs to determine the location where the difference occurs as the first end 2a and the second end 2b of the film 2.

When the first end 2a and the second end 2b are specifically designated, the calculation unit 40 is based on, for example, the arrangement position of the end detector 31A and the end detector 31B and the obtained brightness data (or image). The positions of the first end 2a and the second end 2b are used to calculate the positions (for example, the traveling position) of the first end 2a and the second end 2b in the manufacturing apparatus 10 (or the conveying mechanism). When the end of the transport roller R can be specified from the brightness data obtained through the end detector 31A and the end detector 31B, for example, the end of the transport roller R and the first of the film 2 in the brightness data The arrangement relationship between the end 2a and the second end 2b and the actual position of the end of the conveying roller R are used to calculate the position of the first end 2a and the second end 2b in the manufacturing device 10 (or conveying mechanism) ( (E.g. travel position)

The calculation unit 40 is obtained based on the first acquisition result obtained by the upstream position acquisition device 30 _UP arranged in the upstream part preselected from the plurality of acquisition points 20 and the downstream position acquisition device 30 _DOWN arranged in the downstream part. According to the second acquisition result of, the positions (for example, the traveling position) of the first end 2a and the second end 2b in each of the upstream part and the downstream part are calculated as described above. Furthermore, the calculation unit 40 also calculates the reference position B based on the first acquisition result. The reference position B can be calculated as the center position of the film 2 in the upstream portion, for example. Examples of the upstream part and the downstream part are as described above.

Then, according to the aforementioned calculation results, the first width W1a and the second width W1b in the upstream part are calculated, and the first width W2a and the second width W2b in the downstream part are calculated, and according to the aforementioned formula (1) To formula (3), the difference γ is calculated.

Although the calculation step of the difference γ has been decomposed into a plurality of steps, the description has been made. However, if the positions of the first end portion 2a and the second end portion 2b (for example, the traveling position) can be obtained based on the first and second obtained results in the upstream part and the downstream part, the result and the formula ( 1) It is sufficient to calculate the difference γ to formula (3).

In the aforementioned manufacturing method of the polarizing film 4 and the manufacturing apparatus 10 of the polarizing film 4, the first end portion 2a and the first end portion 2a of the film 2 are obtained by the position obtaining devices 30 respectively arranged at the plurality of obtaining points 20 (plural positions) The position of the second end 2b. With this, the film 2 can be conveyed while the first end 2a can be continuously obtained And the position of the second end 2b. Furthermore, among the positions of the first end portion 2a and the second end portion 2b continuously obtained by the plurality of obtaining points 20, the first end portion 2a and the second end portion 2b obtained at the same time point in the upstream part and the downstream part The position of the end 2b, and the difference γ is calculated. Therefore, in the transport of the film 2, the difference γ of the film 2 can be obtained. In other words, the difference γ can be monitored while the film 2 is being transported.

The difference γ is: between the upstream part and the downstream part, the width of the film 2 on the first end 2a side (first width) and the second end 2b side (second width) are relative to The difference in the rate of change of the reference position B. When the difference γ exceeds the allowable range (the management width of the difference γ) obtained through experiments or simulations in advance, for example, the load on the transport roller R that transports the film 2 is locally increased, and Prone to missing equipment. When the device is missing, the polarizing film 4 becomes defective or the film 2 is broken. Alternatively, when the aforementioned difference γ exceeds the allowable range, the film thickness tends to deviate from the desired state in the width direction. For example, it is easy to produce a difference in the film thickness on both sides of the reference position B in the width direction. In this way, when the film thickness deviates from the desired state, the polarizing film 4 having uniform desired optical characteristics cannot be obtained, or a portion with poor appearance quality occurs. As a result, the material used to manufacture the polarizing film 4 is wasted, resulting in an increase in material cost.

In the manufacturing method of the polarizing film (optical film) 4 and the manufacturing apparatus 10 of the polarizing film 4 described above, the difference γ can be monitored in real time during the transport of the film 2, for example. Therefore, when the difference γ exceeds the allowable range, for example, the production of the polarizing film 4 can be quickly interrupted. In order to make the difference γ into the allowable range when the production is interrupted, it is only necessary to adjust the production conditions of the polarizing film 4. The aforementioned adjustment example includes: adjusting the angle of the conveying roller R by a position adjustment mechanism such as EPC (Edge Position Control), and adjusting the processing tank between the upstream part and the downstream part after calculating the difference γ The distribution of temperature, flow rate, etc. in the width direction, repair and manufacturing device 10 (bearing replacement, transfer roller R replacement), etc. In addition, for example, the manufacturing may be continued while the adjustment difference γ becomes the allowable range. In this way, you can prevent the subsequent steps The fracture of the Nakano film 2 suppresses the production of the polarizing film 4 that would become the aforementioned defective product. Therefore, the polarizing film 4 can be manufactured in a stable step. Furthermore, the polarizing film 4 with stable quality can be manufactured uniformly. Furthermore, the material cost of the polarizing film 4 can be reduced. Furthermore, a good-quality polarizing film (optical film) 4 can be manufactured efficiently, so the manufacturing yield of the polarizing film 4 is improved.

The allowable range of the aforementioned difference γ may be set in each of plural combinations of the upstream portion (upstream position acquiring device 30 _UP ) and downstream portion (downstream position acquiring device 30 _DOWN ), for example. An example of the allowable range is 1.0% or less. For example, the allowable range in at least one combination of the upstream part and the downstream part may be 1.0% or less, and the allowable range in all combinations of plural combinations of the upstream part and the downstream part may be 1.0% or less.

The first width and the second width of the film 2 are easily changed due to at least one of the N treatments performed on the film 2. Therefore, as described above, when the upstream part is before the predetermined treatment among the N processes and the downstream part is after the predetermined treatment, it is easy to monitor the defects in the manufacture of the polarizing film 4 (for example, the width direction of the film 2 The difference γ between the film thickness difference on both sides of the reference position B, equipment failure, breakage of the film 2 in a later step, etc.).

For the same reason, in the case of the aforementioned configuration examples 1 to 4, it is also easy to monitor the difference γ that promotes the defect in the manufacture of the polarizing film 4. For example, in the configuration status, it can be specified that a change in the state before or after a certain process, a change in the state caused by the process, or a change in the state in the middle of the process affects the difference γ. Therefore, when the difference γ is out of the allowable range, it is easy to adjust the manufacturing conditions.

As a result, the material cost of the polarizing film 4 can be further reduced, and the manufacturing yield of the polarizing film 4 can be further improved. In addition, the polarizing film 4 with more stable quality can be uniformly manufactured in a more stable step.

When the acquired first end position and a second end portion 2a of the portion 2b of film 2 acquired at the point ₂₀₁ (N processing performed before), the film 2 has not been generated in characteristics such as linearly polarized light. Therefore, the film 2 is generally a transparent film having no absorption axis. At this time, the first end portion 2a and the second end portion 2b of the film 2 on the transport roller R are detected using the position acquiring device 30 having the end portion detector 31A shown in FIG. The first end 2a and the second end 2b of the film 2 are detected. As a result, the difference γ can be calculated more accurately. Here, although the case where the point 20 ₁ is obtained is illustrated as an example, the same is true for obtaining the points 20 ₂ and 20 ₃ , and the position obtaining device 30 having the end detector 31A shown in FIG. 4 can be used to reliably The first end 2a and the second end 2b of the film 2 are detected.

When the film 2 is dyed and stretched, the film 2 will be given linear polarization characteristics. When the film 2 is conveyed, tension is applied to the film 2 along the conveying direction of the film 2. Therefore, when the film 2 is conveyed on one side while the stretching treatment is gradually performed by any one of swelling treatment, dyeing treatment, cross-linking treatment, and drying treatment, the dyed film 2 is gradually given linear polarization characteristics. Furthermore, as shown in Fig. 1, the drying process is usually performed at the end of the N processes. Therefore, when obtaining the positions of the first end 2a and the second end 2b of the film 2 after the dyeing treatment and the stretching treatment are performed, the position obtaining device having the end detector 31B shown in Fig. 5 can be used. 30, and the first end 2a and the second end 2b are reliably detected. As a result, the difference γ can be calculated more accurately.

As shown in Figs. 4 and 5, in the type in which the position acquisition device 30 includes the housings 34 and 35, the light irradiating portion 32 and the light detecting portions 33 and 36 can be prevented from being corroded by iodine. In the production of the polarizing film 4, since a treatment liquid containing iodine is used, iodine may be present in the production environment, which may corrode, for example, the light detecting parts 33 and 36. In this regard, as shown in FIGS. 4 and 5, by arranging the light irradiating portion 32 and the light detecting portions 33, 36 in the housings 34, 35, the aforementioned corrosion caused by iodine can be prevented. The inside of the casings 34 and 35 are preferably positively pressurized in advance by means of supplying gas or the like.

The present invention is not limited to the foregoing embodiments and various modifications, and of course also includes all changes shown in the scope of the patent application and within the meaning and scope equivalent to the scope of the patent application.

The case of manufacturing a polarizing film as an optical film has been exemplified. However, the present invention can also be applied to the manufacturing method and manufacturing apparatus of an optical film that needs to monitor the difference in the change of the reduction ratio of the first width and the second width of the film during the process of manufacturing the optical film from the film. Another example of the optical film includes a protective film, a retardation film, a surface treatment film, an antireflection film, and a diffusion film.

When the N treatments include dyeing treatment and stretching treatment, the position acquisition device with the end detector 31B shown in Fig. 5 is suitable for the upstream part to obtain the film that has been dyed and stretched. The position of the first end and the second end (the two ends of the film). This is because, in this case, there is a tendency that when the two ends of the film are to be obtained at the upstream position, the film has already produced linear polarization characteristics. When N treatments are performed while conveying the film, the film is gradually subjected to the stretching treatment as described above. Therefore, the position acquiring device having the end detector 31B can also be suitably applied to the case where the upstream part is to detect the first end and the second end of the dyed film.

The method of detecting the first end portion and the second end portion of the film 2 is not particularly limited to the illustrated method. For example, the first end and the second end can also be detected by measuring equipment such as a laser type displacement meter and an LED type displacement meter. The entire film 2 may be imaged by a camera or the like, and the positions of the first end and the second end may be calculated from the obtained image. As shown in Figure 3, in the method of obtaining the positions of the first end 2a and the second end 2b of the film 2, the first end 2a and the second end 2b are respectively arranged to detect the first end 2a The device at the position of the second end portion 2b and the second end portion 2b are sufficient, so it is preferable from the viewpoint of installation space or equipment management (maintenance inspection, etc.).

The stretching treatment in the stretching treatment part is not limited to a wet stretching method, and a dry stretching method may also be used. In the foregoing embodiment, the order of the processing illustrated in order to manufacture the polarizing film may also be It can be changed or combined as appropriate without departing from the scope of the present invention. The number of processing tanks in each processing section may be one or plural. The N processes are not limited to the number of illustrated processes.

The definition of the difference between the first rate of change of the first width of the film (first narrowing rate) and the second rate of change of the second width (second narrowing rate) is not limited to the exemplified definition, as long as it can be expressed The difference between the first rate of change and the second rate of change of the membrane between the upstream portion and the downstream portion may be obtained.

The foregoing embodiments and various modifications can also be appropriately combined without departing from the scope of the present invention.

2: membrane

4: Polarizing film (optical film)

6: Raw material roll

11, 11 ₁ to 11 ₆ : Roll

12, 12 ₁ to 12 ₁₂ : guide roller

13 ₁ : Swelling treatment part

13 ₂ : Dyeing Department

13 ₃ : Cross-linking treatment section

13 ₄ : Cleaning treatment department

13 ₅ : Drying department

20, 20 ₁ to 20 ₁₂ : Get points (multiple parts)

Claims (28)

A method for manufacturing an optical film, which is a method of performing N treatments (N is an integer greater than 1) on a long film to manufacture an optical film; The aforementioned method is to carry out the aforementioned N treatments while conveying the aforementioned film; In the foregoing conveying, the positions of the first end and the second end in the width direction of the film are continuously obtained at a plurality of locations; When the distance between the reference position in the width direction and the position of the first end in the film is the first width, and the distance between the reference position and the second end is the second width, The reference position is calculated based on the first acquisition result of the positions of the first end and the second end in the upstream part of the two parts selected from the plurality of parts, and based on the first acquisition As a result and the second obtained result of the positions of the first end and the second end in the downstream part of the two parts, the first change rate of the first width and the second width are calculated The difference in the second rate of change. The method for manufacturing an optical film according to the first item of the patent application, wherein the reference position in the upstream portion is the center position in the width direction of the film in the upstream portion. The method for manufacturing an optical film as described in item 1 or item 2 of the scope of the patent application, wherein the first rate of change in at least one combination of the upstream part and the downstream part selected from the plurality of parts is The difference in the aforementioned second rate of change is 1.0% or less. The method for manufacturing an optical film as described in item 1 or item 2 of the scope of the patent application, wherein the first among all combinations of the upstream part and the downstream part selected from the plural parts The difference between the rate of change and the aforementioned second rate of change is 1.0% or less. The method for manufacturing an optical film as described in any one of items 1 to 4 of the scope of patent application, wherein the upstream part is a position before one of the N treatments is performed, and the downstream part is The position after the preceding one treatment is performed. The method for manufacturing an optical film as described in any one of items 1 to 4 of the scope of the patent application, wherein the aforementioned N treatments include the i-1th treatment, the ith treatment, and the i+1th treatment (i is an integer above 2); The upstream part is between the position of the i-1th treatment and the position of the i-th treatment, and the downstream part is between the position of the i-th treatment and the position of the i+1th treatment. The method for manufacturing an optical film as described in any one of items 1 to 4 of the scope of the patent application, wherein the aforementioned N treatments include the i-1th treatment and the ith treatment (i is an integer greater than 2 ); The upstream part is located at the position in the i-1th treatment, and the downstream part is between the position of the i-1th treatment and the position of the i-th treatment; or The upstream part and the downstream part are respectively between the position of the i-1th treatment and the position of the i-th treatment; or The upstream part is the position before the i-1th treatment, and the downstream part is the position in the i-1th treatment. According to the method for manufacturing an optical film described in any one of items 1 to 7 of the scope of patent application, in the transportation, the image of the first end and the second end of the film is obtained by the imaging unit. According to the method of manufacturing an optical film described in any one of items 1 to 7 of the scope of the patent application, in the foregoing transportation, the foregoing first is obtained based on the brightness of at least one of the reflected light and the transmitted light from the foregoing film The position of one end and the second end, wherein the reflected light and the penetrating light from the film are caused by the light incident on the film. The method of manufacturing an optical film as described in any one of items 1 to 9 of the scope of patent application, wherein: The aforementioned film is conveyed by conveying rollers; and Light is irradiated to the film on the transport roller, and the positions of the first end and the second end are obtained based on the difference in brightness between the film and the reflected light of the transport roller generated by the irradiated light . According to the method for manufacturing an optical film described in claim 9, wherein the transmitted light is transmitted light from the film, and the transmitted light from the film is incident on the aforementioned film through a polarizing filter. Caused by the light of the film. According to the method for manufacturing the optical film described in item 9 of the scope of patent application, the positions of the first end and the second end of the film are obtained based on the brightness of the light obtained by the passing light through the polarizing film. The method for manufacturing an optical film as described in any one of claims 1 to 12, wherein the N treatments include at least one of swelling treatment, dyeing treatment, stretching treatment, and drying treatment. The method for manufacturing an optical film as described in any one of items 1 to 13 of the scope of patent application, wherein the optical film is a polarizing film. An optical film manufacturing device, which is equipped with: N processing parts (N is an integer greater than or equal to 1), which are used to perform at least processing for imparting optical properties to the film; The transport mechanism is to transport the aforementioned film; A plurality of position acquisition devices are arranged at a plurality of positions on the conveying mechanism, and continuously obtain the first end and the first end in the width direction of the film being conveyed by the conveying mechanism at the plural positions. The location of the two ends; and The calculation part is based on setting the distance between the reference position in the width direction of the film and the position of the first end as the first width, and setting the distance between the reference position and the second end as the second In the case of the width, based on the first acquisition result of the position of the first end and the second end in the upstream position acquisition device selected from the two position acquisition devices selected from the plurality of position acquisition devices, and Calculate the aforementioned reference position, and calculate based on the aforementioned first acquisition result and the second acquisition result of the positions of the first end and the second end in the downstream position acquisition device in the two position acquisition devices, and calculate The difference between the first rate of change of the first width and the second rate of change of the second width. The optical film manufacturing apparatus described in claim 15, wherein the reference position in the arrangement portion of the upstream position obtaining device is the center position in the width direction of the film in the arrangement portion. The optical film manufacturing apparatus described in claim 15 or 16, wherein at least one of the upstream position obtaining device and the downstream position obtaining device selected from the plurality of position obtaining devices is combined The difference between the aforementioned first rate of change and the aforementioned second rate of change is 1.0% or less. The optical film manufacturing device described in claim 15 or 16, wherein a plurality of combinations of the upstream position obtaining device and the downstream position obtaining device selected from the plurality of position obtaining devices The difference between the aforementioned first rate of change and the aforementioned second rate of change in all combinations is less than 1.0%. The optical film manufacturing apparatus described in any one of claims 15 to 18, wherein the upstream position acquisition device is arranged before one of the N processing sections, and the downstream side The position acquisition device is arranged behind the aforementioned one processing unit. The optical film manufacturing apparatus described in any one of items 15 to 19 of the scope of patent application, wherein the aforementioned N processing units include the i-1th processing unit, the i-th processing unit, and the i+th processing unit 1 processing unit (i is an integer greater than 2); The upstream position obtaining device is arranged between the i-1th processing unit and the i-th processing unit; The downstream position obtaining device is arranged between the i-th processing unit and the i+1-th processing unit. According to the manufacturing device of the optical film described in any one of the 15th to 19th items of the scope of the patent application, wherein the N processing units include the i-1th processing unit and the i-th processing unit (i is 2 Above integer); The upstream position acquisition device is arranged at the position of the i-1th processing section, and the downstream position acquisition device is arranged between the i-1th processing section and the i-th processing section; or The upstream position obtaining device and the downstream position obtaining device are respectively arranged between the i-1th processing section and the i-th processing section; or The upstream position acquiring device is arranged before the i-1th processing unit, and the downstream position acquiring device is arranged at the position of the i-1th processing unit. The manufacturing device of the optical film according to any one of the 15th to the 21st claims, wherein at least one of the plurality of position obtaining devices has at least the first end and the The camera at the two ends. The optical film manufacturing apparatus described in any one of the 15th to 21st claims, wherein at least one of the plurality of position acquiring devices has a light detecting unit that detects At least one of the reflected light and the penetrating light of the film, wherein the reflected light and the penetrating light from the film are caused by the light incident on the film. The manufacturing device of the optical film according to any one of the 15th to the 23rd of the scope of patent application, wherein at least one of the plurality of position obtaining devices has a light to irradiate light to the film Irradiation department. The optical film manufacturing device described in item 24 of the scope of patent application, wherein: The aforementioned conveying mechanism has a conveying roller; The light irradiating part irradiates light to the film on the conveying roller; At least one of the plurality of position obtaining devices is based on the difference between the brightness of the reflected light of the film and the conveying roller caused by the light irradiated from the light irradiation portion to the film on the conveying roller, The positions of the first end and the second end of the aforementioned film are obtained. The manufacturing apparatus of the optical film as described in claim 24, wherein a polarizing filter is provided between the light irradiation section and the film. The apparatus for manufacturing an optical film as described in claim 23, wherein a polarizing filter is provided between the light detecting section and the film. The manufacturing apparatus of the optical film according to any one of the 15th to the 27th claims, wherein the N treatment parts include a swelling treatment part, a dyeing treatment part, a cross-linking treatment part, an elongation treatment part, and At least any one of the drying treatment parts.

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