Manufacturing method of resin film conjugate, manufacturing method of polarizer, resin film conjugate, and polarizer

Abstract

To provide a manufacturing method of a resin film conjugate capable of bonding two long resin films in a more accurately positioned state.SOLUTION: A manufacturing method includes a bonding process of bonding a rear end part side of a first resin film 111 and a tip side of a second resin film 112 to form a bonded part 113. The bonding process includes: a first detection process of irradiating width-direction both end areas of the first resin film 111 with first inspection light to detect width-direction both end parts of the first resin film 111; a second detection process of irradiating width-direction both end areas of the second resin film 112 with second inspection light to detect width-direction both end parts of the second resin film 112; a position adjustment process of adjusting a position of at least one of the first and second resin films 112 according to detection results of the first and second detection processes, with regard to the positions of the width-direction both end parts of the first and second resin films 112; and a bonded part formation process of forming the bonded part 113 after the position adjustment process.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a method for producing a resin film joint, a method for producing a polarizing plate, a resin film joint, and a polarizing plate. [Background technology]

[0002] As a conventional technique in this technical field, there is a method for manufacturing an optical film described in Patent Document 1. In this method for manufacturing an optical film, a film is sent out and stretched in the conveying direction in a stretching tank. When the supply of the film is completed, the rear end of the preceding film (hereinafter referred to as the "first film") is joined to the front end of a new film (hereinafter referred to as the "second film"). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-100110 A Summary of the Invention [Problem to be solved by the invention]

[0004] If there is misalignment between the first film and the second film when joining the rear end of the first film and the front end of the second film, the film as the joined body of the first film and the second film is likely to break when a stretching process is performed in a subsequent process.

[0005] Therefore, an object of the present invention is to provide a method for manufacturing a resin film joint capable of joining two long resin films in a more accurately aligned state, a method for manufacturing a polarizing plate using the above-mentioned manufacturing method for a resin film joint, a resin film joint, and a polarizing plate including the above-mentioned resin film joint. [Means for solving the problem]

[0006] [1] A joining process for joining a long first resin film and a long second resin film arranged such that the longitudinal direction is a transport direction, the joining process comprising: joining a rear end side of the first resin film and a front end side of the second resin film to form a joint portion such that a joining angle with a width direction perpendicular to the transport direction is 20° or more and 60° or less, the joining process including irradiating both end regions in the width direction of the first resin film with a first inspection light, and receiving the first inspection light transmitted through or reflected by the both end regions in the width direction of the first resin film with a light receiving unit, a second detection step of detecting both widthwise end portions of the second resin film by irradiating both widthwise end regions of the second resin film with a second inspection light and receiving the second inspection light that has been transmitted through or reflected by both widthwise end regions of the second resin film with a light receiving unit; a position adjustment step of adjusting a position of at least one of the first resin film and the second resin film based on detection results of the first detection step and the second detection step; and a joint formation step of forming the joint after the position adjustment step.

[0007] [2] The method for manufacturing a resin film joint body described in [1], wherein the first resin film and the second resin film have different widths, and in the position adjustment step, a first shift amount between a first end of both widthwise ends of the first resin film and an end of both widthwise ends of the second resin film corresponding to the first end is equal to a second shift amount between a second end of both widthwise ends of the first resin film and an end of both widthwise ends of the second resin film corresponding to the second end.

[0008] [3] A method for manufacturing a resin film joint body, comprising: a joining process for joining a long first resin film and a long second resin film arranged so that the longitudinal direction is a transport direction, the joining process comprising joining a rear end side of the first resin film and a front end side of the second resin film to form a joint so that a joint angle with a width direction perpendicular to the transport direction is 20° or more and 60° or less, the joining process including: a reference laser line forming process for forming reference laser lines indicating positions of both width direction ends of the position reference film by irradiating laser light to both width direction ends of a position reference film selected from among the first resin film and the second resin film; a position adjustment process for adjusting positions of both width direction ends of a position adjusted film, one of the first resin film and the two resin films, relative to the reference laser line; and a joint forming process for forming the joint after the position adjustment process.

[0009] [4] The method for manufacturing a resin film joint body described in [3], wherein the joining step further includes a detection step of detecting both widthwise end regions of the position reference film by irradiating a first inspection light onto both widthwise end regions of the position reference film and receiving the first inspection light transmitted through or reflected by the both widthwise end regions of the position reference film with a light receiving unit, and the reference laser line forming step forms the reference laser line by irradiating laser light onto both widthwise end regions of the position reference film detected in the detection step.

[0010] [5] The joining process further includes a distance acquisition process for acquiring a first distance between the reference laser line corresponding to a first end of both widthwise ends of the position reference film and an end of the position adjustable film corresponding to the first end, and a second distance between the reference laser line corresponding to a second end of both widthwise ends of the position reference film and an end of the position adjustable film corresponding to the second end, by imaging both widthwise end regions of the position adjustable film, and the position adjustment process adjusts the position of the position adjustable film based on the first distance and the second distance.A method for manufacturing a resin film joint body as described in [3] or [4].

[0011] [6] A method for manufacturing a resin film joint body described in [3] or [4], wherein the widths of the first resin film and the second resin film are different, and in the position adjustment process, the position of the film to be adjusted is adjusted so that the amount of deviation between the reference laser line corresponding to a first end of both widthwise ends of the position reference film and the end of the film to be adjusted corresponding to the first end is the same as the amount of deviation between the reference laser line formed at a second end of both widthwise ends of the position reference film and the end of the film to be adjusted corresponding to the second end.

[0012] [7] The method for producing a resin film joint body according to any one of [1] to [6], wherein an angle between a first center line that runs along the longitudinal direction of the first resin film and is located at the center in the width direction and a second center line that runs along the longitudinal direction of the second resin film and is located at the center in the width direction is adjusted to be −15° or more and 15° or less.

[0013] [8] The method for producing a resin film joined body according to any one of [3] to [7], wherein the positioning reference film is the first resin film.

[0014] [9] The method for producing a resin film joined body according to any one of [1] to [8], further comprising a step of stretching the first resin film and the second resin film in the transport direction while continuously feeding the first resin film and the second resin film joined in the joining step in the transport direction, starting with the first resin film.

[0015]

[10] A method for manufacturing a polarizing plate, comprising a step of laminating a protective film to a resin film joint manufactured by the method for manufacturing a resin film joint described in [9], wherein the first resin film and the second resin film are polyvinyl alcohol-based resin films.

[0016]

[11] A resin film joint comprising: a long first resin film; and a long second resin film arranged along the longitudinal direction of the first resin film, wherein a rear end side of the first resin film and a front end side of the second resin film are joined, a joint angle of the joint of the first resin film and the second resin film with respect to a width direction perpendicular to the longitudinal direction is 20° or more and 60° or less, lengths of the first resin film and the second resin film are different, and a first shift amount between a first end of both width direction ends of the first resin film and an end of both width direction ends of the second resin film corresponding to the first end is equal to a second shift amount between a second end of both width direction ends of the first resin film and an end of both width direction ends of the second resin film corresponding to the second end.

[0017]

[12] A polarizing plate comprising the resin film joint body according to

[11] and a protective film bonded to the resin film joint body, wherein the first resin film and the second resin film are polyvinyl alcohol-based resin films, and the resin film joint body is stretched along a longitudinal direction. Effect of the Invention

[0018] According to the present invention, there are provided a method for manufacturing a resin film joint capable of joining two long resin films in a more accurately aligned state, a method for manufacturing a polarizing plate using the above-mentioned manufacturing method for the resin film joint, a resin film joint, and a polarizing plate including the above-mentioned resin film joint. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram of a production line for a resin film bonded body according to one embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of a polarizing plate according to one embodiment. [Diagram 3] FIG. 3 is a schematic diagram of an example of a resin film joint body constituted by a first resin film and a second resin film. [Figure 4] FIG. 4 is a plan view showing the first resin film that has been cut obliquely. [Diagram 5] FIG. 5 is a plan view showing the second resin film cut at an angle. [Figure 6] FIG. 6 is a diagram for explaining a joining unit in the production line shown in FIG. [Figure 7] FIG. 7 is a diagram for explaining the positional relationship between two resin films in a step of bonding the two resin films. [Figure 8] FIG. 8 is a diagram for explaining a step of joining two resin films. [Figure 9] FIG. 9 is a diagram for explaining a step of cutting both widthwise ends of the joint portion. [Figure 10] FIG. 10 is a diagram for explaining a first embodiment of the step of aligning the first resin film and the second resin film. [Figure 11] FIG. 11 is a diagram for explaining an example of a joining machine used in the first embodiment. [Figure 12] FIG. 12 is a diagram for explaining a second embodiment of the step of aligning the first resin film and the second resin film. [Figure 13] FIG. 13 is a diagram for explaining a modification of the second embodiment of the step of aligning the first resin film and the second resin film. [Figure 14] FIG. 14 is a diagram for explaining a third embodiment of the step of aligning the first resin film and the second resin film. [Figure 15] FIG. 15 is a diagram illustrating a step of adjusting the positions of the center lines of the first resin film and the second resin film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted. The dimensional ratios of the drawings do not necessarily correspond to those in the description.

[0021] Fig. 1 is a schematic diagram for explaining one embodiment of the present invention. Hereinafter, an example of the production of a polarizing film as an optical film will be described. Fig. 1 is a schematic diagram of a production line for a polarizing film. The production line 1 shown in Fig. 1 includes a supply section 2, a processing section 3, and a drying section 4.

[0022] The supply section 2 includes a turret device 5, a bonding unit 6, and an accumulation mechanism 7.

[0023] The turret device 5 has a turret arm 5a. The turret arm 5a is provided on a support 5c so as to be rotatable about a shaft 5b. At a first end of the turret arm 5a, a raw roll 100 in which a long resin film F is rolled is rotatably supported by a shaft 5d. At a second end of the turret arm 5a, a raw roll 100 in which a long resin film F is rolled is rotatably supported by a shaft 5e. The second end of the turret arm 5a is an end opposite to the first end of the turret arm 5a.

[0024] In this embodiment, the resin film F is a polyvinyl alcohol-based resin film. The polyvinyl alcohol resin may be polyvinyl formal, polyvinyl acetal, or polyvinyl butyral.

[0025] FIG. 1 shows that of the two original rolls 100, the original roll 100 supported by the shaft 5d is positioned at a film supply position for the resin film F, and the resin film F is being unwound from the original roll 100.

[0026] When the supply of the resin film F from the original roll 100 supported by the shaft 5d is completed, the turret arm 5a rotates. As a result, the original roll 100 supported by the shaft 5e moves to the film supply position. As a result, the resin film is unwound from the original roll 100 that has moved. While the resin film F is being supplied from the original roll 100 supported by the shaft 5e, a new original roll 100 is attached to the shaft 5d. The above-mentioned operation is repeated, and the resin film F is continuously supplied. As a result, in the manufacturing process of the polarizing film, there are a leading resin film F and a trailing resin film F. For convenience of explanation, the leading resin film F is referred to as the first resin film 111, and the trailing resin film F is referred to as the second resin film 112 (see FIG. 3).

[0027] The joining unit 6 is a part in the production line 1 that carries out a joining process of joining a preceding resin film F (first resin film 111) and a following resin film F (second resin film 112). The resin film joined body obtained by joining two resin films F (first resin film 111 and second resin film 112) is referred to as a resin film 11. The resin film 11 is conveyed from the joining unit 6. In the resin film 11, since the first resin film 111 is the preceding resin film F, from the joining unit 6 onwards, the first resin film 111 and the second resin film 112 are conveyed in that order.

[0028] The accumulation mechanism 7 includes a fixed roll 7a and a movable roll 7b. By moving the movable roll 7b up and down, the time required to bond the first resin film 111 and the second resin film 112, etc. can be adjusted.

[0029] The processing section 3 performs a process for imparting linear polarization properties to the resin film 11. Specifically, the processing section 3 performs a stretching process on the resin film 11 and at least a dyeing process. An example of a total stretch ratio of the resin film 11 in the stretching process is 3.0 or more and 8.0 or less. An example of the processing section 3 will be described with reference to FIG. 1.

[0030] An example of the processing section 3 includes a swelling tank 3a, a dyeing tank 3b, a crosslinking tank 3c, and a washing tank 3d. The processing section 3 is configured to stretch the resin film 11 while transporting the resin film 11 by a roll-to-roll method. Specifically, the processing section 3 has a plurality of nip sections 8a. The nip section 8a has a pair of nip rolls. The resin film 11 is transported between the pair of rolls. The nip section 8a sandwiches the transported resin film 11 between the pair of rolls and sends it out in the transport direction. The pair of nip rolls of the nip section 8a on the downstream side in the transport direction are rotated at a higher speed than the nip rolls of the nip section 8a on the upstream side in the transport direction, thereby stretching the resin film 11. The resin film 11 may be stretched overall while passing through the swelling tank 3a, the dyeing tank 3b, the crosslinking tank 3c, and the washing tank 3d, or may be stretched in any of the tanks. In addition to the nip portion 8a, the processing portion 3 is provided with a plurality of guide rolls 8b for regulating the moving path of the resin film 11 so that the resin film 11 passes through each tank.

[0031] The swelling tank 3a is a portion where a swelling treatment process is carried out on the resin film 11. The swelling treatment is carried out for the purposes of removing foreign matter on the surface of the resin film 11, removing plasticizers in the resin film 11, imparting ease of dyeing in a post-process, plasticizing the resin film 11, etc. The conditions for the swelling treatment can be determined within a range in which these purposes can be achieved and in which defects such as extreme dissolution or devitrification of the resin film 11 do not occur. An example of a treatment liquid in the swelling tank 3a is water. Therefore, the swelling treatment can also serve as a water washing treatment for the resin film 11.

[0032] The dyeing tank 3b is a portion where a dyeing process is carried out on the resin film 11. A treatment liquid for the dyeing process is stored in the dyeing tank 3b. The resin film 11 is immersed in the treatment liquid contained in the dyeing tank 3b, whereby the resin film 11 is subjected to the dyeing process.

[0033] The crosslinking tank 3c is a portion where a crosslinking treatment step is carried out on the resin film 11. A treatment liquid for the crosslinking treatment is stored in the crosslinking tank 3c. The resin film 11 is immersed in the treatment liquid contained in the crosslinking tank 3c, whereby the crosslinking treatment is carried out on the resin film 11. The crosslinking treatment is carried out for the purposes of making the resin film 11 water-resistant by crosslinking, adjusting the hue, etc.

[0034] Cleaning tank 3d 、 This is a section where a cleaning process is performed on the resin film 11. A processing liquid for the cleaning process is stored in the cleaning tank 3d. The resin film 11 is immersed in the processing liquid contained in the cleaning tank 3d, whereby the resin film 11 is subjected to the cleaning process. An example of the processing liquid for the cleaning process is water.

[0035] The drying section 4 is a section that performs a drying process on the resin film 11. An example of the drying section 4 is a drying device. The resin film 11 that has been cleaned in the cleaning tank 3d is carried into the drying section 4. The drying section 4 dries the resin film 11 while the resin film 11 passes through the drying section 4.

[0036] In the production line 1, the resin film 11 discharged from the joining unit 6 is subjected to a stretching process in the processing section 3. Therefore, the production line 1 produces a long stretched resin film (resin film joined body) 11.

[0037] In the above-mentioned production line 1, the resin film 11 discharged from the joining unit 6 passes through the swelling tank 3a, the dyeing tank 3b, the crosslinking tank 3c, the washing tank 3d and the drying section 4 in this order. As a result, the resin film 11 is subjected to the swelling process, the dyeing process, the crosslinking process, the washing process and the drying process in this order. Furthermore, as described above, the resin film 11 is subjected to the stretching process while being transported. As a result, the resin film 11 produced in the production line 1 is given linear polarization properties. As a result, the resin film 11 produced in the production line 1 functions as a polarizing film 12. That is, the polarizing film 12 is produced by the production line 1.

[0038] A lamination step is carried out to laminate a protective film 13 to at least one of the front and back surfaces of the resin film 11 as the polarizing film 12 produced as described above, thereby obtaining the polarizing plate 10 shown in Fig. 2. Fig. 2 is a schematic diagram showing the configuration of a polarizing plate according to one embodiment. Fig. 2 illustrates an embodiment in which the protective film 13 is provided on the front surface of the polarizing film 12, but a further protective film 13 may be laminated to the back surface of the polarizing film 12. An example of the protective film 13 is a cellulose-based film, and an example of the cellulose-based film is a TAC (triacetyl cellulose) film.

[0039] Next, an outline of the joining process performed in the joining unit 6 will be described. In the joining process, a joining portion 113 of the first resin film 111 and the second resin film 112 is formed as shown in Fig. 3. Fig. 3 is a schematic diagram of an example of the resin film 11 constituted by the first resin film 111 and the second resin film 112.

[0040] The joint 113 is inclined at an angle (joining angle) θ1 with respect to the width direction perpendicular to the conveyance direction of the resin film 11. The angle θ1 is 20° or more and 60° or less. The joining unit 6 also forms inwardly arc-shaped recesses 114 at both width direction ends of the joint 113. An example of the radius of curvature of the recesses 114 is 30 mm or more and 2000 mm or less.

[0041] 3, the transport direction is shown as the X direction, and the width direction is shown as the Y direction. Hereinafter, the transport direction and the width direction will be referred to as the X direction and the Y direction, and the direction perpendicular to the X direction and the Y direction will be referred to as the Z direction. The X direction is also the transport direction of the first resin film 111 and the second resin film 112.

[0042] 3, one of both ends in the width direction of the first resin film 111 is referred to as a first end 111a, and the other is referred to as a second end 1111b, and one of both ends in the width direction of the second resin film 112 is referred to as a first end 112a, and the other is referred to as a second end 112b. The first end 112a is an end located on the same side as the first end 111a when viewed from the Z direction, and the second end 112b is an end located on the same side as the second end 111b when viewed from the Z direction. That is, the first end 112a and the second end 112b are end portions corresponding to the first end 111a and the second end 111b.

[0043] An example of the joining process carried out in the joining unit 6 will now be described in detail.

[0044] When the first resin film 111 and the second resin film 112 are joined, at the stage when the supply of the first resin film 111 is completed, that is, at the stage when all the resin films F (corresponding to the first resin film 111) are unwound from the original roll 100 set at the film supply position, the rear end 111c side of the first resin film 111 and the front end 112c side of the second resin film 112 are cut so as to be inclined at the above-mentioned angle θ1, as shown in FIG. 4 and FIG. 5. FIG. 4 is a plan view showing the first resin film 111 cut at an angle. FIG. 5 is a plan view showing the second resin film 112 cut at an angle. In FIG. 4 and FIG. 5, the first resin film 111 and the second resin film 112 before being cut are shown by two-dot chain lines. The rear end and front end portions inclined at the angle θ1 in the first resin film 111 and the second resin film 112 after the regions shown by the two-dot chain lines are separated are also referred to as the rear end 111c and the front end portion 112c. The area including the rear end 111c of the first resin film 111 and which is to be joined to the second resin film 112, and the area including the front end 112c of the second resin film 112 and which is to be joined to the first resin film 111 are sometimes referred to as the intended joining areas of the first resin film 111 and the second resin film 112.

[0045] As described above, after the first resin film 111 and the second resin film 112 are cut, the first resin film 111 and the second resin film 112 are set in the bonding machine 20 shown in FIG. 6. In this embodiment, the second resin film 112 is disposed closer to the receiving table 22, and the first resin film 111 is disposed closer to the seal head 21. Therefore, the first resin film 111 is disposed on the second resin film 112. The arrangement of the first resin film 111 and the second resin film 112 may be reversed, but the following description will be given taking as an example a case where the first resin film 111 is disposed on the second resin film 112.

[0046] Fig. 6 is a schematic diagram showing a schematic configuration of the joining unit 6. As shown in Fig. 6, the joining machine 20 has a seal head 21 and a receiving table 22. The seal head 21 and the receiving table 22 are arranged to be spaced apart in the Z direction. The seal head 21 and the receiving table 22 are members for heat-sealing (thermal fusing) the first resin film 111 and the second resin film 112 arranged therebetween by pressing the first resin film 111 and the second resin film 112 while heating them.

[0047] In order to form the joint 113 (see FIG. 3), the seal head 21 is also arranged in a state inclined at the angle θ1 with respect to the width direction perpendicular to the conveying direction. In order to realize the above heat sealing, the seal head 21 is configured to be able to heat the first resin film 111 and the second resin film 112. In this embodiment, the seal head 21 has a heater. The receiving stand 22 may also be configured to be able to heat the first resin film 111 and the second resin film 112. When performing the heat sealing as described above, in order to fix the first resin film 111 to the seal head 21, the seal head 21 is configured to be able to suck the first resin film 111 and fix it to the seal head 21. Similarly, the receiving stand 22 is configured to be able to suck the second resin film 112 and fix it to the receiving stand 22. Specifically, the seal head 21 and the receiving stand 22 have a suction mechanism.

[0048] FIG. 7 is a diagram showing the first resin film 111 and the second resin film 112 set in the bonding machine 20 as viewed from the thickness direction of the first resin film 111 (or the second resin film 112).

[0049] When the first resin film 111 and the second resin film 112 are arranged as described above, a positioning process is performed therefor. For example, when the first resin film 111 and the second resin film 112 have the same width, the first resin film 111 and the second resin film 112 are aligned so that the first end 111a of the first resin film 111 and the first end 112a of the second resin film 112 are in the same position and the second end 111b of the first resin film 111 and the second end 112b of the second resin film 112 are in the same position when viewed from the Z direction.

[0050] 7, it is preferable that the width of the subsequent second resin film 112 is wider than the width of the first resin film 111. This allows the entire area of ​​the intended joining region of the first resin film 111, which has already been fed into the processing section 3 and is in a stretched state, to be joined to the second resin film 112, thereby making it possible to suppress the occurrence of wrinkles, etc., in the stretched first resin film 111 and improving the transport stability of the first resin film 111. As a method for making the width of the subsequent second resin film 112 wider than the width of the first resin film 111, there is given, for example, humidifying the second resin film.

[0051] As shown in FIG. 7, when the width of the subsequent second resin film 112 is wider than the width of the first resin film 111, the positions of the first resin film 111 and the second resin film 112 are adjusted so as to satisfy the following condition I. (Condition I) When viewed from the Z direction, a first misalignment amount g1 between the first end 111a and the first end 112a is the same as a second misalignment amount g2 between the second end 111b and the second end 112b.

[0052] The above-mentioned alignment is performed to suppress breakage of resin film 11 during processing in processing section 3, and non-uniformity in width when the width of resin film 11 changes due to swelling, etc. The first misalignment amount g1 and the second misalignment amount g2 being "the same" means that they may be within a certain tolerance range within which breakage, etc. can be suppressed.

[0053] The meaning of the first misalignment amount g1 and the second misalignment amount g2 being "the same" has been explained above with respect to the case where the width of the first resin film 111 and the width of the second resin film 112 are different, but the same applies to the case where the width of the first resin film 111 and the width of the second resin film 112 are the same. In the following explanation, unless otherwise specified, a form in which the width of the second resin film 112 is wider than the width of the first resin film 111 will be described.

[0054] Next, the regions to be joined of the first resin film 111 and the second resin film 112 are pressed by the heated seal head 21 and the receiving stand 22. This causes the regions to be joined including the rear end 111c of the first resin film 111 and the front end 112c of the second resin film 112 to be heat-sealed, resulting in the formation of a joint 113 as shown in Fig. 8 (joint formation process). Examples of heat sealing conditions are as follows: Temperature: around 200℃. Required time (including cooling time after heating): 2 seconds or more and 10 seconds or less Pressure: 0.2MPa or more and 0.8MPa or less

[0055] By forming the joint 113 as described above, the resin film 11 is obtained as a resin film joint body. When the alignment is performed so as to satisfy the condition I, the first misalignment amount g1 and the second misalignment amount g2 in the resin film 11 are the same.

[0056] After the first resin film 111 and the second resin film 112 are joined, both widthwise ends of the joint 113 are cut inwardly into arc shapes while the resin film 11 is pressed against a receiving stand 32 by an end cutter 31, as shown by the outline arrow in Fig. 9. This results in a resin film 11 having inwardly arc-shaped recesses 114 formed at both widthwise ends of the joint 113, as shown in Fig. 3.

[0057] During the bonding of the first resin film 111 and the second resin film 112, the resin film 11 in the accumulation mechanism 7 is supplied to the processing section 3. Therefore, the bonding of the first resin film 111 and the second resin film 112 can be performed without stopping the production line 1.

[0058] When bonding the first resin film 111 and the second resin film 112, it is important to accurately align the first resin film 111 and the second resin film 112. Focusing on this point, the alignment step included in the bonding step will be described in detail. Three embodiments with different alignment methods will be described below.

[0059] (First embodiment) In the first embodiment, a reference laser line for alignment is formed by irradiating laser light to both widthwise ends of a positioning reference film selected from the first resin film 111 and the second resin film 112 (reference laser line forming process).

[0060] Thereafter, the positions of both widthwise ends of the film to be position adjusted, that is, the first resin film 111 or the second resin film 112, are adjusted based on the reference laser line (position adjusting step).

[0061] The first embodiment will be specifically described with reference to Fig. 10. Fig. 10 illustrates an example in which a first resin film 111 is the position reference film and a second resin film 112 is the film to be adjusted.

[0062] (Reference laser line formation process) In the reference laser line forming step, as shown in FIG. 10, the first irradiating unit 41a irradiates the first end 111a with a linear laser beam L1a, and the second irradiating unit 41b irradiates the second end 111b with a linear laser beam L1b. At this time, the first end 111a is irradiated with the laser beam L1a so that the extending direction of the linear laser beam L1a coincides with the extending direction of the first end 111a, and the second end 111b is irradiated with the laser beam L1b so that the extending direction of the linear laser beam L1b coincides with the extending direction of the second end 111b. The laser beam L1a and the laser beam L1b are visible light. The first irradiating unit 41a and the second irradiating unit 41b are disposed on the opposite side of the second resin film 112 from the first resin film 111. The first irradiating unit 41a and the second irradiating unit 41b may be line laser devices.

[0063] The first irradiating section 41a and the second irradiating section 41b may be disposed slidably along the Y direction so that the first end section 111a can be irradiated with the laser light L1a and the second end section 111b can be irradiated with the laser light L1b.

[0064] A first reference laser line 40a indicating the position of the first end 111a is formed by the laser light L1a, and a second reference laser line 40b indicating the position of the second end 111b is formed.

[0065] The first reference laser line 40a and the second reference laser line 40b are projected onto the second resin film 112. Even if the second resin film 112 is not present at the position of at least one of the first reference laser line 40a and the second reference laser line 40b, the first reference laser line 40a and the second reference laser line 40b are projected onto the second resin film 112 by moving the second resin film 112.

[0066] (Position adjustment process) In the position adjustment process, the first end 112a is aligned with the first reference laser line 40a, and the second end 112b is aligned with the second reference laser line 40b. Specifically, the alignment is performed so as to satisfy the above condition I.

[0067] 11 is a schematic diagram of one form of a joining machine 20 used in the joining step described in the first embodiment. FIG 11 is a schematic diagram of the joining machine 20 as viewed from the processing section 3 side shown in FIG 1.

[0068] An example of the joining machine 20 has a support table 23 that supports the seal head 21, and a support table 24 that supports the receiving table 22. A first irradiation unit 41a and a second irradiation unit 41b are attached to the support table 23. The first irradiation unit 41a and the second irradiation unit 41b are attached to the support table 23 and spaced apart in the Y direction. The first irradiation unit 41a and the second irradiation unit 41b may each be attached to the support table 23 so as to be movable in the Y direction. For example, the first irradiation unit 41a and the second irradiation unit 41b may each be attached to the support table 23 using a slide mechanism.

[0069] Two scale plates 25 may be attached to the receiving stand 22. In this case, in the reference laser line forming step, the laser light L1a and the laser light L1b are irradiated, so that the first reference laser line 40a is projected onto the scale plate 25, and the second reference laser line 40b is projected onto the scale plate 25. Therefore, in the position adjustment step, it is easy to adjust the position of the second resin film 112 based on the scale of the scale plate 25. In particular, when adjusting the first deviation amount g1 between the first reference laser line 40a and the first end 111a and the second deviation amount g2 between the second reference laser line 40b and the second end, the first deviation amount g1 and the second deviation amount g2 can be objectively grasped, so that the position of the second resin film 112 can be adjusted more accurately. The scale plate 25 may be attached to the support 22 so that the reference position of the scale plate 25 (e.g., the portion where the memory is "0") can be aligned with the position of the first reference laser line 40a or the second reference laser line 40b.

[0070] In the first embodiment, the position of the second resin film 112 is adjusted based on reference laser lines (specifically, the first reference laser line 40a and the second reference laser line 40b) indicating the positions of both widthwise ends of the first resin film 111. Therefore, for example, the position of the second resin film 112 can be adjusted more accurately than when the position of the second resin film 112 is adjusted relative to the first resin film 111 based on the experience of an operator while visually checking both widthwise ends of the first resin film 111 and both widthwise ends of the second resin film 112.

[0071] Second embodiment In the second embodiment, a first inspection light is irradiated onto both widthwise end regions of the first resin film 111, and the first inspection light reflected by the both widthwise end regions of the first resin film 111 is received by a light receiving unit, thereby detecting both widthwise end regions of the first resin film 111 (first detection process). A second inspection light is irradiated onto both widthwise end regions of the second resin film 112, and the second inspection light reflected by the both widthwise end regions of the second resin film 112 is received by a light receiving unit, thereby detecting both widthwise end regions of the second resin film 112 (second detection process). The order of the second detection process and the first detection process is not limited. Usually, the first detection process and the second detection process are performed simultaneously.

[0072] After the first and second detection steps are performed, the position of at least one of the first resin film 111 and the second resin film 112 is adjusted based on the detection results of the first and second detection steps (position adjustment step).

[0073] The first detection step, the second detection step, and the position adjustment step will be specifically described with reference to Fig. 12. In the second embodiment, the first resin film 111 is a position reference film that serves as a reference for alignment, and the second resin film 112 is a film to be adjusted in position.

[0074] (First detection process) 12, in the first detection step, the first end 111a is detected by a detection unit U arranged near the first end 111a, and the second end 111b is detected by a detection unit U arranged near the second end 111b. The detection unit U is arranged on the opposite side of the second resin film 112 from the first resin film 111. The detection units U corresponding to the first end 111a and the second end 111b have the same configuration. Therefore, the detection unit U will be described taking the case of detecting the first end 111a as an example.

[0075] The detection unit U has an irradiation unit 51 and a light receiving unit 52. The irradiation unit 51 irradiates an area (first end area) including the first end 111a with inspection light L2. The irradiation unit 51 may be, for example, an LED light source. The light receiving unit 52 receives reflected light from the first end 111a area. The light receiving unit 52 may be an area sensor. Unless otherwise specified, the light receiving unit 52 is a camera (imaging unit), which is an example of an area sensor.

[0076] An image of the irradiation area of ​​the inspection light L2 is obtained from the reflected light detected by the light receiving unit 52. Since the intensity of the reflected light differs between the inside and outside of the first resin film 111 across the first end 111a, the first end 111a can be detected by analyzing the image.

[0077] The detection unit U has been described using the case of detecting the first end 111a as an example, but as described above, the configuration of the detection unit U for detecting the second end 111b is the same as that of the detection unit U for detecting the first end 111a. Thus, similar to the case of the first end 111a, the irradiating section 51 of the detection unit U arranged for the second end 111b irradiates the area including the second end 112b (the second end area) with the inspection light L2, and the light receiving section 52 receives the inspection light L2 reflected by the second end area, thereby detecting the position of the second end 111b.

[0078] (Second detection process) In the second detection step, as shown in Fig. 12, the first end 112a is detected by a detection unit U arranged near the first end 112a, and the second end 112b is detected by a detection unit U arranged near the second end 112b. In Fig. 12, the detection unit U for the second resin film 112 is arranged between the first resin film 111 and the second resin film 112, but the detection unit U for the second detection step may be arranged on the opposite side of the second resin film 112 to the first resin film 111.

[0079] The configuration of the detection unit U corresponding to the first end 112a and the second end 112b is the same as that of the detection unit U corresponding to the first end 111a. Thus, similarly to the case of the first end 111a, the irradiation unit 51 of the detection unit U arranged for each of the first end 112a and the second end 112b irradiates the region including the first end 112a (first end region) and the region including the second end 112b (second end region) with the inspection light L2, and the light receiving unit 52 receives the inspection light L2 reflected by the first end region and the second end region, thereby detecting the positions of the first end 112a and the second end 111b.

[0080] (Position adjustment process) In the position adjustment step, the positions of the first resin film 111 and the second resin film 112 are adjusted based on the detection results in the first and second detection steps. Specifically, the first end 112a is positioned relative to the position of the first end 111a detected in the first detection step, and the second end 112b is positioned relative to the position of the second end 111b. At this time, the position of the second resin film 112 is adjusted so as to satisfy the above condition I.

[0081] In the position adjustment step, every time the position of the second resin film 112 is moved, the second detection step may be performed, and the position of the second resin film 112 may be adjusted while referring to the detection result in the second detection step.

[0082] In the second embodiment, in the first detection step, the positions of the first end 111a and the second end 111b are detected using a detection unit U, and in the second detection step, the positions of the first end 112a and the second end 112b are detected using a detection unit U. In the position adjustment step, the positions of the first resin film 111 and the second resin film 112 are adjusted based on the detection results of the first detection step and the second detection step.

[0083] Therefore, it is possible to adjust the positions of the first resin film 111 and the second resin film 112 more objectively and accurately than if an operator were to adjust the positions of the first resin film 111 and the second resin film 112 while checking both widthwise ends of the first resin film 111 and both widthwise ends of the second resin film 112 with the naked eye.

[0084] For example, by mounting the receiving base 22 on a moving mechanism, the alignment of the first resin film 111 and the second resin film 112 can be automated. In this case, the detection unit U and the moving mechanism can be controlled by a control device. An example of a method for aligning the first resin film 111 and the second resin film 112 in the case of automation will be described.

[0085] The control device controls the detection units U corresponding to the first end 111a and the second end 111b, respectively, to detect the positions of both widthwise ends of the first resin film 111 (first detection step). Specifically, the detection result of the light receiving section 52 of the detection unit U is analyzed to obtain the positions of both widthwise ends (the first end 111a and the second end 111b) of the first resin film 111.

[0086] The control device controls the detection units U corresponding to the first end 112a and the second end 112b, respectively, to detect the positions of both end portions of the second resin film 112 (second detection step). Specifically, the detection result of the light receiving section 52 of the detection unit U is analyzed to obtain the positions of both end portions (the first end portion 112a and the second end portion 112b) of the second resin film 112 in the width direction.

[0087] The control device calculates a first misalignment amount g1 and a second misalignment amount g2 using the acquired positions of both widthwise ends of the first resin film 111 and the acquired positions of both widthwise ends of the second resin film 112 (misalignment amount calculation step).

[0088] The control device determines whether or not the calculated first deviation amount g1 and second deviation amount g2 satisfy condition I (determination step).

[0089] If the result of the determination step indicates that the first misalignment amount g1 and the second misalignment amount g2 do not satisfy condition I, the control device controls the receiving table 22 to suck the second resin film 112 and fix the second resin film 112 to the receiving table 22. After fixing the second resin film 112 to the receiving table 22 in this manner, the control device controls the movement mechanism to move the position of the receiving table 22 by a predetermined amount (moving configuration or position adjustment step). This causes the second resin film 112 to move.

[0090] After moving the second resin film 112 as described above, the control device performs the second detection step again, and based on the result of the second detection step, performs the misalignment amount calculation step and the determination step in that order. The second detection step, the misalignment amount calculation step, the determination step, and the position adjustment step are repeated until it is determined in the determination step that the first misalignment amount g1 and the second misalignment amount g2 satisfy the condition I.

[0091] When it is determined in the determination step that the first misalignment amount g1 and the second misalignment amount g2 satisfy the condition I, the alignment of the first resin film 111 and the second resin film 112 is completed.

[0092] In the alignment process of the second embodiment, in the first detection process and the second detection process, the positions of both widthwise ends of the first resin film 111 and the positions of both widthwise ends of the second resin film 112 are obtained as data using light. Therefore, the alignment process can be automated as described above. By automating the alignment of the first resin film 111 and the second resin film 112, the alignment of the first resin film 111 and the second resin film 112 can be performed more accurately. The automation of the alignment allows the alignment to be performed efficiently.

[0093] (Variation 1) Fig. 13 is a schematic diagram for explaining a modified example of the second embodiment (hereinafter referred to as "Modification 1"). Modification 1 is the same as the second embodiment except that four laser displacement meters 53 are used instead of the four detection units U shown in Fig. 12. Each of the laser displacement meters 53 has an irradiation unit that outputs laser light L3 as inspection light, and a light receiving unit that receives the laser light L3 reflected by an object to be measured for displacement. Therefore, the laser displacement meter 53 is also a detection unit that has an irradiation unit that outputs inspection light, and a light receiving unit that receives the reflected inspection light.

[0094] In the first detection process, a laser displacement meter 53 for detecting the position of the first end 111a is moved along the Y direction as viewed from the Z direction so as to straddle the first end 111a to detect the position of the first end 111a, and a laser displacement meter 53 for detecting the position of the second end 111b is moved along the Y direction as viewed from the Z direction so as to straddle the second end 111b to detect the position of the second end 111b.

[0095] An example of a method for detecting the position of the first end 111a will be described below using the case of detecting the first end 111a as an example. By outputting the laser light L3 while moving the laser displacement meter 53 for detecting the position of the first end 111a as described above, the position of the first end region relative to the laser displacement meter 53 can be obtained. When the laser displacement meter 53 moves the first end 111a, for example, from the inside to the outside, the first resin film 111 does not exist beyond the first end 111a, so the detection result clearly changes. The position of the laser displacement meter 53 when such a change occurs is the position of the first end 111a.

[0096] In the second detection step, the laser displacement meter 53 for detecting the position of the first end 112a is moved across the first end 112a along the Y direction as viewed from the Z direction to detect the position of the first end 112a, and the laser displacement meter 53 for detecting the position of the second end 112b is moved across the second end 112b along the Y direction as viewed from the Z direction to detect the position of the second end 112b. An example of a method for detecting the positions of the first end 112a and the second end 112b by the laser displacement meter 53 is similar to that for detecting the position of the first end 111a.

[0097] Modification 1 is similar to the second embodiment except that the positions of the first end 111a and the second end, and the first end 112a and the second end 112b are detected using the laser displacement meter 53. Therefore, modification 1 has the same effect as the second embodiment. By using the detection result of the positions of the first end 111a and the second end, and the first end 112a and the second end 112b using the laser displacement meter 53 instead of the detection result of the detection unit U of the second embodiment, alignment can be automatically performed in the modification as well.

[0098] 13, two laser displacement meters 53 are arranged for the first resin film 111, but one laser displacement meter 53 may be arranged for the first resin film 111. In this case, for example, the positions of the first end 111a and the second end can be obtained by moving the laser displacement meter 53 along the Y direction from the outside of one of both ends of the first resin film 111 to the outside of the other end. Similarly, one laser displacement meter 53 may be arranged for the second resin film 112.

[0099] Third embodiment In the third embodiment, reference laser lines indicating the positions of both ends of the position reference film are formed by irradiating laser light to both widthwise ends of a position reference film selected from the first resin film 111 and the second resin film 112 (reference laser line forming process).

[0100] By imaging the widthwise end regions of the first resin film 111 and the second resin film 112, which are to be adjusted in position, a first distance is obtained between a reference laser line corresponding to a first end of both widthwise ends of the position reference film and an end of the film to be adjusted that corresponds to the first end, and a second distance is obtained between a reference laser line corresponding to a second end of both widthwise ends of the position reference film and an end of the film to be adjusted that corresponds to the second end (distance acquisition process).

[0101] The position of the film to be adjusted is adjusted based on the first distance and the second distance (position adjusting step).

[0102] An example of the reference laser line forming step and the position acquiring step will be described with reference to FIG.

[0103] (Reference laser line formation process) The reference laser line forming process of the third embodiment is the same as the reference laser line forming process described in the first embodiment. That is, as shown in Fig. 14, the first irradiating unit 41a irradiates the first end 111a with a linear laser beam L1a, and the second irradiating unit 41b irradiates the second end with a linear laser beam L1b. This forms a first reference laser line 40a indicating the position of the first end 111a, and a second reference laser line 40b indicating the position of the second end 111b.

[0104] (Distance acquisition process) In the distance acquisition step, similarly to the second detection step in the second embodiment, the detection unit U irradiates the first end region and the second end region of the second resin film 112 with the inspection light L2 and acquires the reflected light, thereby obtaining images of the first end region and the second end region. By performing the reference laser line formation step, the first reference laser line 40a and the second reference laser line 40b are projected onto the second resin film 112. Therefore, if the first reference laser line 40a and the second reference laser line 40b are present within the imaging range (light receiving range) of the light receiving unit 52, the first reference laser line 40a and the second reference laser line 40b are also imaged by the light receiving unit 52. By analyzing the image obtained by the light receiving unit 52, the first distance between the first reference laser line 40a and the first end 112a and the second distance between the second reference laser line 40b and the second end 112b are calculated.

[0105] The position of the first reference laser line 40a indicates the position of the first end 111a. Therefore, the first distance corresponds to the first deviation amount g1. The position of the second reference laser line 40b indicates the position of the second end 111b. Therefore, the second distance corresponds to the second deviation amount g2. Therefore, the distance calculation process can also be called a deviation amount calculation process.

[0106] (Position adjustment process) In the position adjustment step, the position of the second resin film 112 is adjusted with respect to the first resin film 111 based on the first distance and the second distance acquired in the position acquisition step. Specifically, the position of the second resin film 112 is adjusted so that a first misalignment amount g1 corresponding to the first distance and a second misalignment amount g2 corresponding to the second distance satisfy condition I.

[0107] In the alignment step of the third embodiment, the first reference laser line 40a and the second reference laser line 40b represent the positions of the first end 111a and the second end 111b. In the detection step, the positions of the first reference laser line 40a, the second reference laser line 40b, the first end 112a, and the second end 112b are acquired as data, and a first distance (first deviation amount g1) between the position of the first reference laser line 40a and the first end 112a and a second distance (second deviation amount g2) between the position of the second reference laser line 40b and the second end 112b are calculated.

[0108] In the third embodiment, the position of the receiving table 22 is movable and mounted on a moving mechanism controlled by a control device, so that the distance calculation step and the position adjustment step can be performed automatically. Specifically, the image acquired by the detection unit U is analyzed by the control device, and the first distance (first deviation amount g1) and the second distance (second deviation amount g2) are calculated.

[0109] The control device judges whether or not the first misalignment amount g1 corresponding to the first distance and the second misalignment amount g2 corresponding to the second distance satisfy condition I (judging step). When the first misalignment amount g1 and the second misalignment amount g2 do not satisfy condition I, the control device controls the moving mechanism to move the receiving stand 22 (moving step or position adjusting step). At this time, the control device controls the receiving stand 22 to suck the second resin film 112 and fix it to the receiving stand 22. The second resin film 112 moves with the movement of the receiving stand 22. When the second resin film 112 has moved a predetermined amount, the distance calculation step is performed again. The judgment is performed based on the result. By performing such distance calculation step, judgment step, and moving step (position adjusting step) until it is judged that the first misalignment amount g1 and the second misalignment amount g2 satisfy condition I, the positions of the first resin film 111 and the second resin film 112 can be automatically adjusted.

[0110] In this manner, by automatically adjusting the positions of the first resin film 111 and the second resin film 112, the position adjustment can be performed accurately and efficiently.

[0111] (Variation 2) A modified example of the third embodiment (hereinafter referred to as "Modification 2") will be described. In Modification 2, the first detection step in the second embodiment is performed before the reference laser line forming step. In the reference laser line forming step, the laser light L1a and the laser light L1b are irradiated according to the positions of the first end 111a and the second end 112b acquired in the first detection step. In this case, the positions of the first reference laser line 40a and the second reference laser line 40b more accurately represent the positions of the first end 111a and the second end 111b, so that the first resin film 111 and the second resin film 112 can be aligned with high accuracy.

[0112] For example, the first detection step and the reference laser line formation step can be automated by mounting the first irradiation unit 41a and the second irradiation unit 41b on a slide mechanism that can be controlled by a control device. In this case, as described in the third embodiment, the entire alignment step can be automated by automating the steps after the reference laser line formation step.

[0113] In the various embodiments and modifications related to the positioning step described above, the first resin film 111 and the second resin film 112 can be aligned more accurately. As a result, when the resin film 11 is stretched by the processing unit 3, the same stretched state is likely to be achieved on both sides of the center line in the bonding region of the first resin film 111 and the second resin film 112. As a result, breakage of the resin film 11 during the stretching process and width non-uniformity when the width of the resin film 11 changes due to the influence of swelling caused during the processing in the processing unit 3 are suppressed. The bonding region is a region where the bonding portion 113 is formed in the conveying direction. The center line is a line that passes through the center in the width direction and extends in the longitudinal direction.

[0114] When the width of the second resin film 112 is wider than the width of the first resin film 111, the first end 111a and the first end 112a are misaligned, and the second end 111b and the second end 112b are misaligned. In this case, by aligning the first resin film 111 and the second resin film 112 so as to satisfy condition I, it is more likely that the same stretched state will be achieved on both sides of the center line in the bonding region.

[0115] The joint 113 is formed at an angle θ1 of 20° or more and 60° or less with respect to the width direction perpendicular to the conveying direction. The width direction component of the joint 113 becomes smaller as the joint angle increases. Therefore, by forming the joint 113 at an angle, the shrinkage difference between the area where the joint 113 is formed and other areas decreases. However, if the joint angle of the joint 113 with respect to the width direction becomes too large, it becomes necessary to increase the width of the jointer 20, which tends to increase the cost required for production (including the purchase cost of the jointer 20). Therefore, by setting the angle θ1 within the above angle range, it is possible to suppress non-uniformity in the width of the resin film 11 when the resin film 11 is stretched and to suppress breakage of the resin film 11, while increasing the production cost.

[0116] 8, when recesses 114 are formed on both sides of joint 113, for example, even if the first resin film 111 and the second resin film 112 have different widths and unjoined portions are generated on both sides of joint 113, the unjoined portions are cut off when forming recesses 114. As a result, when resin film 11 is stretched, no difference in the stretching state (uneven stretching) occurs between unjoined portions and joint 113, and therefore breakage of resin film 11 can be suppressed.

[0117] In order to further suppress breakage of the resin film 11 during the stretching process, in the manufacturing method of the stretched resin film 11 (or the manufacturing method of the polarizing film), as shown in Figure 15, the positions of the first resin film 111 and the second resin film 112 may be adjusted (center line position adjustment process) so that the angle θ2 between the center line (first center line) C1 of the first resin film 111 and the center line (second center line) C2 of the second resin film 112 is greater than -15° and less than 15°.

[0118] The center line C1 is a line that runs along the longitudinal direction of the first resin film 111 and passes through the center in the width direction. The center line C2 is a line that runs along the longitudinal direction of the second resin film 112 and passes through the center in the width direction.

[0119] The center line position adjustment can be performed by disposing a film position adjustment mechanism in the transport path of at least one of the first resin film 111 and the second resin film 112, and adjusting at least the positions of the first resin film 111 and the second resin film 112 based on the position adjustment mechanism. An example of the position adjustment mechanism is EPC (Edge Position Control).

[0120] In the embodiment including such a center line position adjustment step, not only are the positions of the first resin film 111 and the second resin film 112 adjusted in the vicinity of the joint 113, but also the positions of the first resin film 111 and the second resin film 112 are adjusted in a wider range in front of and behind the joint 113 in the conveying direction. Therefore, a region in which the resin film 11 is curved with respect to the conveying direction is unlikely to occur in the vicinity of the joint 113. As a result, while the resin film 11 is being conveyed in the processing section 3, the resin film 11 is prevented from meandering or from receiving unnecessary loads due to misalignment of the center lines C1 and C2.

[0121] The center line position adjustment step may be performed by checking the resin film 11 after the joining step and releasing the joining of the first resin film 111 and the second resin film 112 if the center lines C1, C2 are misaligned. Alternatively, the center line position adjustment step may be performed before the joining step is performed. Fig. 15 shows the state before the first resin film 111 and the second resin film 112 are subjected to the cutting process described with reference to Figs. 4 and 5, but the center line position adjustment step may be performed after the cutting process is performed.

[0122] The present invention is not limited to the above-described embodiments and various modifications, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0123] The detection unit U in which the irradiation unit 51 and the light receiving unit 52 are arranged to form a reflective optical system has been exemplified. However, the irradiation unit 51 and the light receiving unit 52 may form a transmissive optical system. For example, when the irradiation unit 51 is arranged on one surface side of the first resin film 111, the light receiving unit 52 may be arranged on the other surface side of the first resin film 111. In this case, the light receiving unit 52 receives the inspection light L2 output from the irradiation unit 51 and transmitted through the first resin film 111.

[0124] A case has been described in which the first resin film 111 and the second resin film 112 are aligned by shifting the position of the second resin film 112 with respect to the first resin film 111. However, the first resin film 111 and the second resin film 112 may be aligned by shifting the position of the first resin film 111 with respect to the second resin film 112. In this case, the second resin film 112 is a position reference film, and the first resin film 111 is a film to be adjusted in position.

[0125] The width of the first resin film 111 may be wider than the width of the second resin film 112. The first resin film 111 and the second resin film 112 may be films made of different materials.

[0126] Although the method for producing the resin film 11 (resin film joint) has been described including the stretching process by the processor 3 shown in FIG. 1, the method for producing the resin film joint does not necessarily have to include the stretching process.

[0127] The materials of the first resin film 111 and the second resin film 112 are selected depending on the product (for example, an optical film) to be formed using them. Therefore, the materials of the first resin film 111 and the second resin film 112 are not limited to polyvinyl alcohol-based resin.

[0128] The above-described embodiments and various modified examples may be combined as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0129] 10...polarizing plate, 11...resin film (resin film joint), 12...polarizing film, 13...protective film, 40a...first reference laser line (reference laser line), 40b...second reference laser line (reference laser line), 51...irradiation section, 52...light receiving section, 111...first resin film, 111a...first end (one end of both ends in the width direction of the first resin film), 111b...second end (the other end of both ends in the width direction of the first resin film), 1 11b...first end (one of both widthwise ends of the second resin film), 112b...second end (the other of both widthwise ends of the second resin film), 111c...rear end, 112...second resin film (see Figure 2), 112c...tip, 113...joint, C1...center line (first center line), C2...center line (second center line), L1a, L1b...laser light, L2...inspection light, θ1...angle (joint angle), θ2...angle.

Claims

1. a joining step of joining a long first resin film and a long second resin film arranged such that the longitudinal direction is a transport direction, the joining step including joining a rear end side of the first resin film and a front end side of the second resin film to form a joint portion such that a joint angle with a width direction perpendicular to the transport direction is 20° or more and 60° or less; The joining step includes: a first detection step of detecting both ends in the width direction of the first resin film by irradiating both end regions in the width direction of the first resin film with a first inspection light and receiving the first inspection light transmitted through or reflected by the both end regions in the width direction of the first resin film with a light receiving unit; a second detection step of detecting both ends in the width direction of the second resin film by irradiating both end regions in the width direction of the second resin film with a second inspection light and receiving the second inspection light transmitted through or reflected by the both end regions in the width direction of the second resin film with a light receiving unit; a position adjustment process of adjusting a position of at least one of the first resin film and the second resin film based on detection results of the first detection process and the second detection process; a joint forming step of forming the joint after the position adjusting step; Including, A method for producing a resin film bonded body.

2. the first resin film and the second resin film have different widths; In the position adjustment step, a position of at least one of the first resin film and the second resin film is adjusted so that a first shift amount between a first end of both width direction ends of the first resin film and an end of both width direction ends of the second resin film corresponding to the first end is equal to a second shift amount between a second end of both width direction ends of the first resin film and an end of both width direction ends of the second resin film corresponding to the second end. The method for producing the resin film joined body according to claim 1 .

3. a joining step of joining a long first resin film and a long second resin film arranged such that the longitudinal direction is a transport direction, the joining step including joining a rear end side of the first resin film and a front end side of the second resin film to form a joint portion such that a joining angle with a width direction perpendicular to the transport direction is 20° or more and 60° or less; The joining step includes: a reference laser line forming step of forming reference laser lines indicating positions of both end sides in the width direction of the position reference film by irradiating laser light to both end sides in the width direction of the position reference film selected from the first resin film and the second resin film; a position adjustment step of adjusting the positions of both ends in a width direction of a film to be adjusted, the film being one of the first resin film and the second resin film, relative to the reference laser line; a joint forming step of forming the joint after the position adjusting step; Including, A method for producing a resin film bonded body.

4. the joining step further includes a detection step of detecting both ends in the width direction of the position reference film by irradiating both end regions in the width direction of the position reference film with a first inspection light and receiving the first inspection light transmitted through or reflected by the both end regions in the width direction of the position reference film with a light receiving unit, In the reference laser line forming step, a laser beam is irradiated onto both ends in the width direction of the position reference film detected in the detection step to form the reference laser line. The method for producing a resin film joined body according to claim 3 .

5. The joining process further includes a distance acquisition process for acquiring a first distance between the reference laser line corresponding to a first end of both widthwise ends of the position reference film and an end of the position adjustable film corresponding to the first end, and a second distance between the reference laser line corresponding to a second end of both widthwise ends of the position reference film and an end of the position adjustable film corresponding to the second end, by imaging both widthwise end regions of the position adjustable film; In the position adjustment step, a position of the position adjustable film is adjusted based on the first distance and the second distance. The method for producing a resin film joined body according to claim 3 .

6. The first resin film and the second resin film have different widths, In the position adjustment step, the position of the position-adjusted film is adjusted so that an amount of deviation between the reference laser line corresponding to a first end of both widthwise ends of the position reference film and an end of the position-adjusted film corresponding to the first end is equal to an amount of deviation between the reference laser line formed on a second end of both widthwise ends of the position reference film and an end of the position-adjusted film corresponding to the second end. The method for producing a resin film joined body according to claim 3 .

7. an angle between a first center line that is aligned along the longitudinal direction of the first resin film and located at the center in the width direction and a second center line that is aligned along the longitudinal direction of the second resin film and located at the center in the width direction is adjusted to be greater than or equal to -15° and less than or equal to 15°; The method for producing a resin film joined body according to claim 3 .

8. the position reference film is the first resin film; The method for producing a resin film joined body according to claim 3 .

9. The method further includes a step of stretching the first resin film and the second resin film in the transport direction while continuously feeding the first resin film and the second resin film joined in the joining step in the transport direction in order from the first resin film. The method for producing the resin film joined body according to claim 1 .

10. A step of laminating a protective film to the resin film joint body produced by the method for producing a resin film joint body according to claim 9, The first resin film and the second resin film are polyvinyl alcohol-based resin films. A method for manufacturing a polarizing plate.

11. A long first resin film; a second resin film disposed along a longitudinal direction of the first resin film; Equipped with a rear end side of the first resin film and a front end side of the second resin film are joined together, a joining angle of the first resin film and the second resin film with respect to a width direction perpendicular to the longitudinal direction is 20° or more and 60° or less, the first resin film and the second resin film have different lengths in the width direction, a first shift amount between a first end of both width direction ends of the first resin film and an end of both width direction ends of the second resin film corresponding to the first end, and a second shift amount between a second end of both width direction ends of the first resin film and an end of both width direction ends of the second resin film corresponding to the second end, are equal to each other. Resin film bonded body.

12. The resin film joint body according to claim 11, a protective film attached to the resin film joint; and Equipped with the first resin film and the second resin film are polyvinyl alcohol-based resin films, The resin film joint body is stretched along the longitudinal direction. Polarizing plate.

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