JP7320382B2 - Manufacturing method and manufacturing apparatus for polarizing film - Google Patents

Description

The present invention relates to methods and apparatus for manufacturing polarizing films. In particular, the present invention relates to a manufacturing method and a manufacturing apparatus for a polarizing film capable of reducing waste of the polarizing film caused by splicing the two films constituting the polarizing film.

BACKGROUND ART Conventionally, polarizing films containing polarizers have been used as constituent materials for liquid crystal display devices, polarized sunglasses, and the like. A polarizing film is composed of, for example, a polarizer dyed with a dichroic substance such as iodine and a protective film for protecting the polarizer. A long strip-shaped polarizing film is usually produced by laminating a long strip-shaped protective film to at least one side of a long strip-shaped polarizer by a roll-to-roll method (see, for example, Patent Document 1). The produced long belt-shaped polarizing film is cut into a size and shape according to the application, and used for a liquid crystal display device and the like.

Here, a splicing process may be performed on the protective film that constitutes the polarizing film. The splicing process is a process of joining the front end of a new long strip-shaped film to the rear end of the preceding long strip-shaped film by adhesive tape or heat welding.

Patent Literature 2 discloses a continuous feeding device that splices optical films, conveys them, and continuously feeds them.
Specifically, in the apparatus described in Patent Document 2, as described in FIG. 7 of Patent Document 2, the first optical film delivered from the first delivery roller (first roll R1) is held by the first adsorption means. 103 , the first fixing member 102 , the transfer-side suction means 303 and the transfer-side fixing member 302 . A first cutting means 101 cuts the first optical film between the two fixing members. On the other hand, the leading end of the second optical film drawn out from the second drawing roller (second roll R2) is fixed by the second adsorption means 203 and the second fixing member 202 . The rear end portion of the first optical film fixed by the transport side adsorption means 303 and the transport side fixing member 302 is moved to the front end portion of the second optical film fixed by the second adsorption means 203 and the second fixing member 202. After that, the rear end portion of the first optical film and the front end portion of the second optical film are joined with a tape.
The continuous supply device described in Patent Document 2 can join (splice) the first optical film and the second optical film as described above, and continuously supply the optical film.

JP-A-2002-365432 Japanese Patent No. 6390848

In the case of manufacturing a polarizing film in which protective films are laminated on both sides of a polarizer, a continuous supply device as described in Patent Document 2 is applied, and both protective films are spliced to the bonding position. When supplied, the position of the splice portion (joint portion) of one protective film and the position of the splice portion of the other protective film may shift in the longitudinal direction of the polarizing film.

The following two factors are mainly conceivable as the cause of the misalignment of the splice portion of each protective film.
(1) One protective film and the other protective film have different distances (path lengths) from the delivery position from the delivery roller to the bonding position, so the execution timing of the splicing process to be executed for both protective films is tentatively Even if they are the same, the positions where the splice portions of the respective protective films are bonded to the polarizer are shifted.
(2) Since one protective film and the other protective film differ in the total length of the film wound around the delivery roller before the start of delivery (roll length), the remaining length of each protective film (wound around the delivery roller without being delivered) The timing at which the length of the film remaining in the unrolled state is the same is different. Therefore, even if the splicing process is performed individually at the timing when the remaining length of each protective film reaches the same predetermined value, the position where the spliced portion of each protective film is attached to the polarizer is shifted.

Of the manufactured long strip-shaped polarizing film, the splice portion of each protective film and the vicinity thereof cannot be used as a product and are cut and discarded. If the positions of the splice parts of each protective film are the same or close to each other, the number of parts to be cut and discarded can be reduced. need to be cut and discarded, resulting in a decrease in the yield of the polarizing film.

In the above example, a case where a polarizing film is manufactured by bonding protective films to both sides of a polarizer and a splicing process is performed on both protective films was described as an example. A similar problem arises when manufacturing a polarizing film by laminating films together and splicing the polarizer and the protective film.

An object of the present invention is to provide a manufacturing method and a manufacturing apparatus for a polarizing film that can reduce the waste of the polarizing film caused by the splicing process performed on the two films that make up the polarizing film. do.

In order to solve the above problems, the present invention provides a method for producing a polarizing film by bonding a protective film to at least one side of a polarizer by a roll-to-roll method, comprising the polarizer and a Two films, which are protective films to be laminated together, or two films, which are protective films to be laminated on both sides of the polarizer, are respectively transported from a feeding position wound around a feeding roller to a bonding position, A remaining length calculation step of calculating the remaining length of each of the two films wound around the delivery roller, and the remaining length of the two films calculated in the remaining length calculation step. When at least one of them becomes equal to or less than a predetermined threshold value, the execution timing is controlled so that the positional deviation L of the splice portion of the two films at the bonding position is 50 mm ≤ L ≤ 500 mm. and a splicing step of splicing the two films.

According to the present invention, in the residual length calculation step, the residual lengths of the two films (polarizer and protective film, or two protective films) are calculated. Then, in the splicing process, when at least one of the remaining lengths of the two films becomes equal to or less than a predetermined threshold value, the positional deviation of the spliced portion of the two films at the bonding position (longitudinal direction of the films) Execution timing is controlled such that (displacement in transport direction) L falls within a predetermined range (50 mm≦L≦500 mm) , and the splicing process is executed for the two films.
As described above, according to the present invention, instead of individually determining the execution timing of the splicing process for the two films according to the remaining length of each film, the position of the spliced portion of the two films at the bonding position is determined. Since the execution timing of the splicing process for the two films is controlled so that the deviation is within a predetermined range (50 mm ≤ L ≤ 500 mm) , the positional deviation of the splice portion can be kept within a predetermined range, It is possible to reduce the waste of the polarizing film.

In the present invention, when the path length, which is the distance between the feeding position and the bonding position of the two films, is the same, in the splicing process, if the execution timing of the splicing process for the two films is the same, the bonding process can be performed. It is possible to have the same splice location for the two films at the mating location.
However, in practice, the path lengths of the two films are often different.
Therefore, preferably, in the splicing process, the execution timing of the splicing process is controlled in consideration of the path length difference, which is the distance between the feeding position and the bonding position of the two films.
In the preferred method described above, the "distance between the feeding position and the bonding position of the two films" means the length of the transport path of the two films between the feeding position and the bonding position. do.

According to the preferred method described above, even if the path lengths of the two films are different, the misalignment of the splice portion can be kept within a predetermined range.
The difference between the path lengths of the two films may be calculated in advance from the design drawing of the continuous feeding device that executes the splicing process, or may be measured in advance.

In the present invention, various methods are conceivable as methods for calculating the remaining lengths of the two films in the remaining length calculation step. , the remaining length is preferably calculated.
Specifically, the remaining length calculating step calculates the length of the two films wound around the delivery roller based on the number of rotations of the delivery roller and the transport speed of the two films delivered from the delivery roller. A first step of calculating winding diameters; a second step of calculating thicknesses of the two films based on temporal changes in winding diameters of the two films; winding diameters of the two films; and a third step of calculating the remaining length of the two films based on the thickness of the two films.

According to the preferred method described above, for example, by attaching an encoder to the rotation shaft of the delivery roller and measuring the number of rotations of the delivery roller (or in addition to this, by simply measuring the transport speed of the two films), , the remaining length of the two films can be easily calculated.
In the preferred method described above, the "winding diameter" means the diameter of the outermost edge of the film wound around the delivery roller.

Further, in order to solve the above problems, the present invention provides an apparatus for manufacturing a polarizing film by laminating a protective film on at least one side of a polarizer by a roll-to-roll method, comprising the polarizer and the polarizer. Two protective films to be laminated on one side, or two protective films to be laminated on both sides of the polarizer, are transported from a feeding position wound around a feeding roller to a bonding position. In addition, a continuous supply device configured to be able to perform a splicing process respectively, a remaining length calculating means for calculating the remaining length of each of the two films wound around the delivery roller, and the remaining length calculating means. When at least one of the remaining lengths of the two films obtained by the above operation becomes equal to or less than a predetermined threshold value, the positional deviation L of the splice portion of the two films at the bonding position is 50 mm≦L≦500 mm. and control means for controlling execution timing so as to cause the continuous supply device to perform the splicing process for the two films.

According to the present invention, it is possible to reduce waste of the polarizing film caused by the splicing process performed on the two films constituting the polarizing film.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the schematic structural example of the manufacturing apparatus of the polarizing film which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a flowchart explaining the schematic procedure of the manufacturing method (execution method of a splicing process) of the polarizing film which concerns on one Embodiment of this invention.

Hereinafter, with reference to the accompanying drawings as appropriate, the manufacturing method and manufacturing apparatus for a polarizing film according to an embodiment of the present invention will be described by taking as an example the case of manufacturing a polarizing film by attaching protective films to both sides of a polarizer. explain.
It should be noted that each drawing is for reference only, and that the dimensions, scales and shapes of the members shown in each drawing may differ from the actual ones.

FIG. 1 is a schematic diagram showing a schematic configuration example of a polarizing film manufacturing apparatus (hereinafter simply referred to as “manufacturing apparatus” as appropriate) according to the present embodiment. FIG. 1(a) is an overall configuration diagram of the manufacturing apparatus, and FIG. 1(b) is an enlarged view of the vicinity of the delivery roller. The bold arrows shown in FIG. 1 indicate the transport direction of each film.
As shown in FIG. 1, a manufacturing apparatus 100 according to the present embodiment is an apparatus for manufacturing a polarizing film F by bonding protective films F2a and F2b to a polarizer F1 by a roll-to-roll method. , a processing tank 2 , a drying device 3 , a continuous supply device 10 , a remaining length calculating means 20 , a control means 30 , a conveying roller R, and a winding roller 4 . Note that the actual manufacturing apparatus 100 includes a gravure coater that applies an adhesive to the polarizer F1 and/or the protective films F2a and F2b, and an adhesive that is cured after bonding the polarizer F1 and the protective films F2a and F2b together. It further includes a known configuration (not shown) such as an active energy ray irradiation device for applying light.

In manufacturing the polarizing film F using the manufacturing apparatus 100 shown in FIG. 1, first, the raw film F0 wound around the feeding roller 1 is fed out and immersed in the treatment bath in the treatment tank 2 to perform various treatments. Apply.
As the raw film F0, a film containing a hydrophilic polymer film (for example, a polyvinyl alcohol-based film) is used, preferably a hydrophilic polymer film. Examples of films containing hydrophilic polymer films include films in which a hydrophilic polymer film and a non-hydrophilic polymer film (eg, polyethylene terephthalate-based film, etc.) are laminated.
Although illustration is omitted, the treatment tank 2 is, for example, a swelling treatment tank for swelling the original film F0, and an iodine treatment tank for the original film F0 that has been subjected to the swelling treatment. Dyeing treatment tank for performing dyeing treatment with a dichroic dye such as, Cross-linking treatment tank for cross-linking the dyed raw film F0, Stretching for stretching the cross-linked raw film F0 A processing bath and a washing processing bath for washing the stretched original film F0 are provided. Since the specific contents of the treatment in each treatment bath can be applied to known ones, the detailed description thereof will be omitted here.

A polarizer F1 is obtained by drying the raw film F0 treated in the treatment tank 2 in the drying device 3. FIG. Although the thickness of the polarizer F1 is not particularly limited, it is generally about 1 to 80 μm, preferably 1 to 20 μm.

Next, the protective films F2a and F2b fed and transported from the delivery rollers 60 constituting the continuous supply device 10 are bonded to both surfaces of the polarizer F1 by the bonding rollers 50 constituting the continuous supply device 10. FIG. One protective film F2a is supplied by the continuous supply device 10a, and the other protective film F2b is supplied by the continuous supply device 10b. The polarizing film F is obtained by attaching the protective films F2a and F2b to both surfaces of the polarizer F1, and the obtained polarizing film F is wound up by the winding roller 4.
As the protective films F2a and F2b, for example, a triacetyl cellulose film is used. Further, an acrylic film, a cycloolefin film, a polyethylene terephthalate film, or the like can also be used as the protective films F2a and F2b. As the protective films F2a and F2b, the same film may be used, or different films may be used. The thickness of the protective films F2a and F2b is not particularly limited, but is generally about 1 to 500 μm, preferably 5 to 200 μm.

Specific configurations of the continuous supply device 10, the remaining length calculation means 20, and the control means 30 provided in the manufacturing apparatus 100 according to the present embodiment will be described below in order.

The continuous supply device 10 conveys the protective films F2a and F2b from the feeding position wound around the feeding roller 60 to the bonding position (the position where the bonding roller 50 bonds the polarizer F1), and the protective films F2a and F2b. A device configured to be able to perform splicing.
The continuous supply device 10a for supplying the protective film F2a includes delivery rollers 60 (60a, 60a') around which the protective film F2a is wound, a splicing device 40 (40a), a bonding roller 50 (50a), and a conveying roller. R and For example, when the protective film F2a delivered from the delivery roller 60a is transported first by the transport roller R, the rear end of the protective film F2a and the leading end of the protective film F2a delivered from the delivery roller 60a' are spliced (joined) by the splicing device 40a, so that the protective film F2a is continuously supplied to the bonding roller 50a.
Similarly, the continuous supply device 10b that supplies the protective film F2b includes delivery rollers 60 (60b, 60b') around which the protective film F2b is wound, a splicing device 40 (40b), and a bonding roller 50 (50b). , and a conveying roller R. For example, when the protective film F2b delivered from the delivery roller 60b is transported first by the transport roller R, the rear end of the protective film F2b and the leading end of the protective film F2b delivered from the delivery roller 60b' are spliced (joined) by the splicing device 40b, and the protective film F2b is continuously supplied to the bonding roller 50b.
Note that the splicing device 40 is provided with components such as an adsorption means, a fixing member, and a cutting means, like the device described in Patent Document 2, and each component operates to join two films. can be used. A more specific configuration of the splice processing device 40 is the same as a known device as described in Patent Document 2, so detailed description thereof will be omitted here.

The remaining length calculation means 20 is means for calculating the remaining lengths of the protective films F2a and F2b wound around the delivery roller 60, respectively.
The remaining length calculation means 20 of the present embodiment includes encoders 21a, 21a', 21b, and 21b'; a calculation means 22 including a computer electrically connected to the encoders 21a, 21a', 21b, and 21b'; It has The encoder 21a is attached to the rotation shaft of the delivery roller 60a and measures the number of rotations of the delivery roller 60a. The encoder 21a' is attached to the rotary shaft of the delivery roller 60a' and measures the number of rotations of the delivery roller 60a'. The encoder 21b is attached to the rotary shaft of the delivery roller 60b and measures the number of revolutions of the delivery roller 60b. The encoder 21b' is attached to the rotating shaft of the delivery roller 60b' and measures the rotation speed of the delivery roller 60b'. The numbers of revolutions of the delivery rollers 60a, 60a', 60b, 60b' respectively measured by the encoders 21a, 21a', 21b, 21b' are inputted to the calculating means 22. The calculation means 22 calculates the remaining lengths of the protective films F2a and F2b using the input number of rotations. A specific procedure for calculating the remaining length will be described later.

The control means 30 is means for causing the continuous supply device 10 to perform the splicing process on the protective films F2a and F2b.
The control means 30 of this embodiment is composed of a computer electrically connected to the splice processing device 40 of the continuous supply device 10 . The control means 30 of this embodiment also has a function as the calculation means 22 of the remaining length calculation means 20 (the same computer is used as the calculation means 22 and the control means 30), but the present invention is not limited to this. Instead, it is possible to configure the control means 30 from a computer separate from the calculation means 22 . It is also possible that the control means 30 and the computing means 22 consist of the same or different programmable logic controllers.
The control means 30 uses the remaining lengths of the protective films F2a and F2b calculated by the remaining length calculating means 20 to determine the execution timing at which the splicing device 40 of the continuous feeding device 10 splices the protective films F2a and F2b. to control. Specific control contents of the execution timing will be described later.

Hereinafter, a method for manufacturing the polarizing film F (method for performing the splicing process) using the manufacturing apparatus 100 according to this embodiment will be specifically described.

FIG. 2 is a flowchart for explaining a schematic procedure of the method for manufacturing the polarizing film F (method for executing the splicing process) according to this embodiment.
As shown in FIG. 2, the manufacturing method according to this embodiment includes a remaining length calculation step S1 and a splice processing step S2. The remaining length calculation step S1 includes a first step S11, a second step S12, and a third step S13.

<Remaining Length Calculation Step S1>
In the remaining length calculating step S1, the remaining lengths of the protective films F2a and F2b wound around the delivery roller 60 are calculated by the remaining length calculating means 20, respectively. For example, regarding the protective film F2a, if the protective film F2a wound around the delivery roller 60a is currently being delivered, the calculation means 22 uses the number of revolutions of the delivery roller 60a measured by the encoder 21a to calculate the delivery The remaining length of the protective film F2a wound around the roller 60a is calculated. Assuming that the protective film F2a wound around the delivery roller 60a' is currently being delivered, the calculating means 22 uses the number of revolutions of the delivery roller 60a' measured by the encoder 21a' to wrap the protective film F2a around the delivery roller 60a'. The remaining length of the protective film F2a thus removed is calculated.
Similarly, for the protective film F2b, for example, if the protective film F2b wound around the delivery roller 60b is currently being delivered, the calculation means 22 uses the number of revolutions of the delivery roller 60b measured by the encoder 21b. to calculate the remaining length of the protective film F2b wound around the delivery roller 60b. Assuming that the protective film F2b wound around the delivery roller 60b' is currently being delivered, the calculating means 22 uses the number of revolutions of the delivery roller 60b' measured by the encoder 21b' to wrap the protective film F2b around the delivery roller 60b'. The remaining length of the protective film F2a thus removed is calculated.

上記の式（１）において、ｔは時間、πは円周率である。
繰出ローラ６０ａの回転数Ｎ（ｔ）及び保護フィルムＦ２ａの巻径Ｄ（ｔ）は時間的に変化し（時間ｔの関数であり）、保護フィルムＦ２ａの搬送速度Ｖが時間的に一定であれば、両者は反比例の関係になる。
なお、上記の式（１）における保護フィルムＦ２ａの搬送速度Ｖは、設定値を予め計算手段２２に記憶させて用いてもよいし、例えば、搬送ローラＲの回転軸にもエンコーダを取り付け、このエンコーダで測定した搬送ローラＲの回転数から計算手段２２が算出してもよい。 [First step S11]
Specifically, when the protective film F2a wound around the delivery roller 60a is currently being delivered, in the first step S11, the calculation means 22 of the remaining length calculation means 20 is calculated as shown in FIG. , the number of rotations of the delivery roller 60a is N(t), and the conveying speed of the protective film F2a delivered from the delivery roller 60a is V, the protective film F2a wound around the delivery roller 60a is calculated based on the following equation (1). A winding diameter D(t) of the film F2a is calculated.

In the above equation (1), t is time and π is the circular constant.
Even if the rotational speed N(t) of the delivery roller 60a and the winding diameter D(t) of the protective film F2a change with time (which is a function of time t), and the conveying speed V of the protective film F2a is constant with time , the two are inversely proportional.
In addition, the transport speed V of the protective film F2a in the above formula (1) may be used by storing a set value in advance in the calculation means 22. For example, an encoder may be attached to the rotating shaft of the transport roller R, and this The calculating means 22 may calculate from the number of revolutions of the conveying roller R measured by an encoder.

Similarly, when the protective film F2a wound around the delivery roller 60a' is currently being delivered, the calculation means 22 sets the number of revolutions of the delivery roller 60a' to N(t), Assuming that the conveying speed of the protective film F2a is V, the winding diameter D(t) of the protective film F2a wound around the feeding roller 60a' is calculated based on the above equation (1). The same applies to the protective film F2b.

上記の式（２）において、Ｄ（ｔ－δｔ）は現在よりも時間δｔだけ前の保護フィルムＦ２ａの巻径、πは円周率、Ｖは保護フィルムＦ２ａの搬送速度である。
計算手段２２が逐次（所定の時間ピッチで）算出した巻径Ｄ（ｔ）を記憶しておくことで、上記の式（２）に基づく計算が可能である。
なお、δｔとしては、例えば、１秒～６０秒の範囲内の任意の時間を例示できる。 [Second step S12]
Next, when the protective film F2a wound around the delivery roller 60a is currently being delivered, in the second step S12, the calculation means 22 of the remaining length calculation means 20 determines the winding diameter D(t) of the protective film F2a. The thickness T of the protective film F2a is calculated based on the temporal change. Specifically, the calculator 22 calculates the thickness T of the protective film F2a based on the following formula (2).

In the above formula (2), D(t−δt) is the winding diameter of the protective film F2a at time δt before the current time, π is the circumference constant, and V is the conveying speed of the protective film F2a.
Calculation based on the above formula (2) is possible by storing the winding diameter D(t) calculated successively (at predetermined time intervals) by the calculating means 22 .
As δt, for example, any time within the range of 1 second to 60 seconds can be exemplified.

Similarly, when the protective film F2a wound around the delivery roller 60a' is currently being delivered, the calculating means 22 also calculates the thickness T of the protective film F2a based on the above equation (2). The same applies to the protective film F2b.

上記の式（３）において、Ｄ０は繰出ローラ６０ａの直径である（図１（ｂ）参照）。繰出ローラ６０ａの直径Ｄ０は、設計値や測定値を予め計算手段２２に記憶させて用いればよい。 [Third step S13]
Finally, when the protective film F2a wound around the delivery roller 60a is currently being delivered, in the third step S13, the calculation means 22 of the remaining length calculation means 20 calculates the length of the protective film F2a calculated in the first step S11. The remaining length RL of the protective film F2a is calculated based on the winding diameter D(t) and the thickness T of the protective film F2a calculated in the second step S12. Specifically, the calculator 22 calculates the remaining length RL of the protective film F2a based on the following formula (3).

In the above formula (3), D0 is the diameter of the delivery roller 60a (see FIG. 1(b)). For the diameter D0 of the delivery roller 60a, a designed value or a measured value may be stored in advance in the calculating means 22 and used.

Similarly, when the protective film F2a wound around the delivery roller 60a' is currently being delivered, the calculating means 22 also calculates the remaining length RL of the protective film F2a based on the above equation (3). The same applies to the protective film F2b.

The residual length RL of the protective films F2a and F2b wound around the delivery roller 60 currently being delivered is calculated by the remaining length calculation means 20 executing the remaining length calculation step S1 described above.

<Splice processing step S2>
In the splicing step S2, the control means 30 causes the splicing device 40 of the continuous supply device 10 to splice the protective films F2a and F2b.
Specifically, the control means 30 stores a predetermined threshold value Th in advance. Then, the control means 30 determines whether or not at least one of the remaining lengths RL of the protective films F2a and F2b calculated in the remaining length calculating step S1 is equal to or less than the threshold value Th (S21 in FIG. 2). . As the threshold value Th, for example, any length within the range of 0.1 m to 10 m can be exemplified.

As a result of the above determination, if both the remaining lengths RL of the protective films F2a and F2b exceed the threshold value Th ("No" in S21 of FIG. 2), the remaining length calculation means 20 calculates the remaining lengths again. Perform step S1. If both the remaining lengths RL of the protective films F2a and F2b exceed the threshold value Th as a result of the remaining length calculating step S1 that is performed again, the same operation is repeatedly performed.
On the other hand, as a result of the above determination, if at least one of the remaining lengths RL of the protective films F2a and F2b is equal to or less than the threshold value Th ("Yes" in S21 of FIG. 2), the control means 30 , the positional deviation L (see FIG. 1A) between the splice portion Sa of the protective film F2a (see FIG. 1A) and the splice portion Sb of the protective film F2b (see FIG. 1A) at the bonding position The execution timing is controlled so as to fall within the range, and the splice processing device 40 is caused to execute the splice processing for the protective films F2a and F2b (S22 in FIG. 2). That is, the control means 30 transmits a control signal to the splice processing device 40a that performs the splice processing on the protective film F2a at the timing when the positional deviation L falls within a predetermined range, and the splice processing device 40a that performs the splice processing on the protective film F2b. A control signal is sent to the processing device 40b to cause each of the splice processing devices 40a and 40b to perform splicing.

Specifically, the control means 30 of the present embodiment controls the path length PL1, which is the distance between the delivery position and the bonding position of the protective film F2a shown in FIG. The execution timing of the splice processing is controlled in consideration of the difference from the path length PL2, which is the distance from the position. In FIG. 1A, for the sake of convenience, the linear distances between the delivery position and the bonding position of the protective films F2a and F2b are illustrated as path lengths PL1 and PL2. are path lengths PL1 and PL2, respectively.
For example, consider a case where PL1−PL2=ΔPL, the conveying speed of the protective films F2a and F2b is V, and at least one of the remaining lengths RL of the protective films F2a and F2b is equal to or less than the threshold value Th. . In this case, if the execution timing of the splicing process is to be controlled so that the positional deviation L=0, the control means 30 sends a control signal to the splice processing device 40a that executes the splicing process for the protective film F2a. , a control signal is transmitted to the splice processing device 40b that performs the splice processing on the protective film F2b with a delay of ΔPL/V. As a result, it is possible to set the positional deviation L=0 between the splice portions Sa and Sb at the bonding position.

Note that the control means 30 preferably controls the execution timing of the splice processing so that the positional deviation L satisfies 0 mm≦L≦500 mm. More preferably, it is controlled so that 0 mm≦L≦100 mm. In the case of L=0 mm, the splice portions Sa and Sb are sandwiched between the bonding rolls 50a and 50b at the same time. may occur. For this reason, most preferably, it is controlled so that 50 mm≦L≦100 mm.
When the difference between the path lengths PL1 and PL2 is ΔPL as described above and the splice processing execution timing is controlled so that the positional deviation L between the splice portions Sa and Sb is L′, the control means 30 controls the splice After the control signal is transmitted to the processing device 40a, the control signal is transmitted to the splice processing device 40b with a delay of time (ΔPL+L')/V or with a delay of time (ΔPL-L')/V. . A value L′ of the desired positional deviation L may be set and stored in the control means 30 in advance.

According to the manufacturing apparatus 100 and the manufacturing method of the polarizing film F using the manufacturing apparatus 100 according to the present embodiment described above, the remaining lengths RL are calculated respectively. Then, in the splice processing step S2, when at least one of the remaining lengths RL of the protective films F2a and F2b becomes equal to or less than a predetermined threshold Th by the control means 30 and the splice processing device 40, the bonding position The execution timing is controlled so that the positional deviation L of the spliced portions Sa, Sb of the protective films F2a, F2b in , falls within a predetermined range, and the splicing process for the protective films F2a, F2b is executed.
That is, instead of individually determining the execution timing of the splicing process for the protective films F2a and F2b according to the remaining lengths of the respective protective films F2a and F2b, the splice portions Sa and Sb of the protective films F2a and F2b at the bonding position are determined. Since the execution timing of the splicing process for the protective films F2a and F2b is controlled so that the positional deviation L of the polarizing film It is possible to reduce the waste of F.

In this embodiment, as the remaining length calculation means 20, a configuration including encoders 21a to 21b′ attached to the rotation shaft of the delivery roller 60 is used, and the protective film Although the case of calculating the remaining length RL of F2a and F2b has been described as an example, the present invention is not limited to this.
For example, if the total length (roll length) of the protective films F2a and F2b wound around the delivery roller 60 before the start of delivery is accurately known, the elapsed time from the start of delivery is measured by a timer, and the protective films F2a and F2b are counted. It is also possible to calculate the remaining length RL of the protective films F2a and F2b by subtracting the value obtained by multiplying the transport speed V of F2b from the total length of the protective films F2a and F2b.
Further, instead of calculating the winding diameter D(t) based on the formula (1), a contact-type or non-contact-type displacement meter is used to measure the outermost edge of the protective films F2a and F2b wound around the delivery roller 60. It is also possible to calculate the winding diameter D(t) by measuring the distance, and use the calculated winding diameter D(t) to calculate the remaining length RL of the protective films F2a and F2b.

Further, in the present embodiment, the case where the polarizing film F is produced by attaching the protective films F2a and F2b to both sides of the polarizer F1 has been described as an example, but the present invention is not limited to this, and the polarizer It is also applicable when manufacturing a polarizing film by laminating a protective film on one side of F1. In this case, the protective film is spliced, and the polarizer F1 (more specifically, the raw film F0 of the polarizer F1) is also spliced. That is, the delivery roller 1 shown in FIG. 1 is replaced with a pair of delivery rollers such as delivery rollers 60b and 60b', and a splicing device such as a splicing device 40b is placed between the replaced pair of delivery rollers and the processing tank 2. A splice processor will be deployed.
In the above example, the raw film F0 of the polarizer F1 is spliced like a film in which a hydrophilic polymer film such as a polyvinyl alcohol film and a non-hydrophilic polymer film such as a polyethylene terephthalate film are laminated. This is particularly effective when the film is easy to apply.

DESCRIPTION OF SYMBOLS 1, 60... Delivery roller 2... Processing tank 3... Drying apparatus 4... Winding roller 10, 10a, 10b... Continuous supply apparatus 20... Remaining length calculation means 21a, 21a' , 21b, 21b'... Encoder 22... Calculation means 30... Control means 40, 40a, 40b... Splice processing device 50, 50a, 50b... Bonding roller R... Conveying roller F0 ... raw film F1 ... polarizer F2a, F2b ... protective film F ... polarizing film Sa, Sb ... splice part 100 ... manufacturing apparatus

Claims (4)

A method for manufacturing a polarizing film by laminating a protective film on at least one side of a polarizer by a roll-to-roll method,
The polarizer and two films that are the protective films bonded to one side of the polarizer, or two films that are the protective films bonded to both sides of the polarizer are wound around delivery rollers, respectively. While being transported from the delivery position to the bonding position, the splicing process is executed respectively,
a remaining length calculation step of calculating the remaining lengths of the two films wound around the delivery roller;
When at least one of the remaining lengths of the two films calculated in the remaining length calculating step becomes equal to or less than a predetermined threshold value, the positional deviation L of the spliced portion of the two films at the bonding position a splicing step of performing splicing on the two films by controlling execution timing so that L is 50 mm ≤ L ≤ 500 mm ;
A method for producing a polarizing film comprising: In the splicing process, the execution timing of the splicing process is controlled in consideration of the difference in path length, which is the distance between the feeding position and the bonding position of the two films.
The manufacturing method of the polarizing film of Claim 1. The remaining length calculation step includes:
A first step of calculating the winding diameters of the two films wound around the delivery roller based on the number of rotations of the delivery roller and the transport speed of the two films delivered from the delivery roller;
a second step of calculating the thickness of the two films based on the temporal change in the winding diameters of the two films;
a third step of calculating the remaining lengths of the two films based on the winding diameters of the two films and the thicknesses of the two films;
The method for producing a polarizing film according to claim 1 or 2. An apparatus for manufacturing a polarizing film by laminating a protective film on at least one side of a polarizer by a roll-to-roll method,
The polarizer and two films that are the protective films to be bonded to one side of the polarizer, or two films that are the protective films to be bonded to both sides of the polarizer are respectively wound around delivery rollers. a continuous feeding device capable of conveying from a delivery position to a bonding position and performing a splicing process on each;
remaining length calculation means for calculating the remaining lengths of the two films wound around the delivery roller;
When at least one of the remaining lengths of the two films calculated by the remaining length calculating means becomes equal to or less than a predetermined threshold value, the positional deviation L of the spliced portion of the two films at the bonding position a control means for controlling the execution timing so that L is 50 mm ≤ L ≤ 500 mm , and causing the continuous supply device to perform the splicing process for the two films;
A manufacturing apparatus for a polarizing film.

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