Method for manufacturing polarizing plate with phase difference layer
By carefully punching and assembling the phase difference film and polarizer original film roll, the axis offset problem of small image display devices is solved, and the precision control and efficient manufacturing of polarizers with phase difference layer are realized, thereby improving the display performance.
Patent Information
- Application Number
- CN202380041880.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-26
- Filing Date
- 2023-04-06
- Publication Date
- 2024-12-31
AI Technical Summary
In small image display devices such as VR goggles, the axis offset of the polarizing mirror absorption axis of the polarization plate with a phase difference layer and the slow axis of the phase difference layer leads to an increase in precision control difficulty, affecting display performance.
By carefully punching the phase difference film and polarizer original film roll, the axis offset between the slow axis and the absorption axis is corrected to ensure that the outer edges of the phase difference layer intermediate and the polarizer intermediate are consistent, and finally assemble at a 45° angle and Brushing to obtain a polarizer with a phase difference layer with precision control.
The extremely precise control of the polarizer absorption axis direction and the slow axis direction of the phase difference layer is realized, the manufacturing efficiency and yield of the small-sized polarizer with phase difference layer is improved, and the performance of the display device is ensured.
Smart Images
Figure CN119234166A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for producing a polarizing plate with a phase difference layer. Background Art
[0002] Image display devices represented by liquid crystal display devices and electroluminescent (EL) display devices (for example, organic EL display devices, inorganic EL display devices) are rapidly becoming popular. In image display devices, in order to achieve image display and / or improve the performance of the image display, a polarizer with a phase difference layer comprising a polarizer and a phase difference film (phase difference layer) has been widely used. On the other hand, new uses of image display devices have been developed in recent years. As an example of such a use, virtual reality (VR) goggles can be cited. In the case of a polarizer with a phase difference layer used in VR goggles, its size is significantly smaller than in previous uses. As a result, the axial offset of the absorption axis of the polarizer and / or the slow axis of the phase difference layer, which has not been a problem in previous uses, has become a substantial problem.
[0003] Prior art literature
[0004] Patent Literature
[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-182162 Summary of the invention
[0006] Problems to be solved by the invention
[0007] The present invention has been made to solve the above-mentioned problems, and its main object is to provide a method for efficiently manufacturing a polarizing plate with a retardation layer in which the absorption axis direction of a polarizer and the slow axis direction of a retardation layer are extremely precisely controlled.
[0008] Solutions to the problem
[0009] The manufacturing method of a polarizing plate with a phase difference layer according to an embodiment of the present invention comprises: for an original film roll of a phase difference film having a slow axis in a longitudinal direction, while correcting the offset of the slow axis relative to the longitudinal direction in a width direction of the original film roll, punching it into a given size, to obtain a single-piece phase difference layer intermediate having a slow axis in the long side direction; punching an original film roll of a polarizing plate having an absorption axis in the longitudinal direction into the same size as the phase difference layer intermediate, to obtain a single-piece polarizing plate intermediate having an absorption axis in a direction of 45° relative to the long side direction; bonding the phase difference layer intermediate to the polarizing plate intermediate so that the outer edges are aligned, to obtain a polarizing plate intermediate with a phase difference layer in which the angle between the absorption axis of the polarizing plate and the slow axis of the phase difference layer is 45°; and, punching out the polarizing plate intermediate with a phase difference layer, to obtain a polarizing plate sheet with a phase difference layer of a given size having an absorption axis in the long side direction.
[0010] In one embodiment, the manufacturing method includes: obtaining 3 to 16 sheets of the retardation layer intermediate in the width direction from the original film roll of the retardation film.
[0011] In one embodiment, the phase difference layer intermediate and the polarizing plate intermediate are rectangular with a short side of 75 mm to 310 mm.
[0012] In one embodiment, the polarizing sheet with a retardation layer is rectangular with a long side of 10 mm to 70 mm and a short side of 10 mm to 70 mm.
[0013] Effects of the Invention
[0014] According to the embodiment of the present invention, it is possible to realize a method for efficiently manufacturing a polarizing plate with a retardation layer in which the absorption axis direction of a polarizer and the slow axis direction of a retardation layer are extremely precisely controlled. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 (a) and (b) are schematic diagrams for explaining a process of obtaining a retardation layer intermediate in the method for producing a polarizing plate with a retardation layer according to an embodiment of the present invention.
[0016] Figure 2 (a) to (c) are schematic diagrams for explaining the process of obtaining a polarizing plate intermediate in the method for producing a polarizing plate with a retardation layer according to an embodiment of the present invention.
[0017] Figure 3 (a) to (c) are schematic diagrams for explaining the process of obtaining a polarizing plate sheet with a retardation layer as a final product in the method for producing a polarizing plate with a retardation layer according to an embodiment of the present invention.
[0018] Explanation of symbols
[0019] 10 Original film roll of phase difference film
[0020] 12 Phase difference layer intermediate
[0021] 20 Polarizer original film roll
[0022] 22 Polarizer Intermediates
[0023] 30 Polarizer intermediate with phase difference layer
[0024] 32 Polarizing plate sheet with phase difference layer (polarizing plate with phase difference layer as final product) DETAILED DESCRIPTION
[0025] Hereinafter, the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In addition, all the drawings are schematic and do not accurately depict actual conditions.
[0026] A. Overview of the method for producing a polarizing plate with a retardation layer
[0027] The manufacturing method of the polarizing plate with a phase difference layer according to the embodiment of the present invention comprises: for an original film roll of a phase difference film having a slow axis in the length direction, while correcting the deviation of the slow axis relative to the length direction in the width direction of the original film roll, punching it into a given size, so as to obtain a single-piece phase difference layer intermediate having a slow axis in the long side direction (for convenience, referred to as a phase difference layer intermediate manufacturing process); punching the original film roll of the polarizing plate having an absorption axis in the length direction into the same size as the phase difference layer intermediate, so as to obtain a single-piece phase difference layer intermediate having an absorption axis in the direction 45° relative to the long side direction. A single polarizer intermediate with a closed axis (for convenience, referred to as a polarizer intermediate production process); the phase difference layer intermediate is bonded to the polarizer intermediate in a manner that the outer edges are aligned to obtain a polarizer intermediate with a phase difference layer in which the angle between the absorption axis of the polarizer and the slow axis of the phase difference layer is 45° (for convenience, referred to as a polarizer intermediate production process with a phase difference layer); and the polarizer intermediate with a phase difference layer is punched to obtain a polarizer sheet with a phase difference layer of a given size having an absorption axis in the long side direction (for convenience, referred to as the final process). Below, each process is described in detail. It should be noted that in this specification, the record of "absorption axis of polarizer" refers to the absorption axis of the polarizer contained in the polarizer.
[0028] B. Phase difference layer intermediate production process
[0029] Figure 1 (a) and Figure 1 (b) is a schematic diagram for explaining the process of preparing the intermediate of the phase difference layer. Figure 1 As shown in (a), prepare the original film roll of the phase difference film. The phase difference film is typically a stretched film of a resin film, and has a slow axis in the length direction of the roll. Representative examples of resins constituting the phase difference film include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins.
[0030] The optical properties of the phase difference film can be appropriately set according to the purpose. The phase difference film has a slow axis, so it shows the relationship of nx>ny. The phase difference film typically shows the refractive index characteristics of nx>ny≥nz. The phase difference film can typically function as a λ / 4 plate. The in-plane phase difference Re(550) of the phase difference film is preferably 100nm~200nm, more preferably 110nm~180nm, and further preferably 130nm~150nm. By making the phase difference film function as a λ / 4 plate, the phase difference film is stacked with a polarizer (polarizer) in a manner such that the slow axis of the phase difference film and the absorption axis of the polarizer are representatively at an angle of 45°, thereby obtaining a polarizer (circular polarizer) with a phase difference layer having an excellent anti-reflection function. Here, "Re(λ)" is the in-plane phase difference measured at 23°C with light of a wavelength of λnm. Therefore, "Re(550)" is the in-plane phase difference measured at 23°C with light of a wavelength of 550nm. When the thickness of the layer (film) is d (nm), Re(λ) can be calculated by the formula: Re(λ)=(nx-ny)×d.
[0031] The phase difference film can exhibit reverse wavelength dispersion characteristics in which the phase difference value increases according to the wavelength of the measuring light, positive wavelength dispersion characteristics in which the phase difference value decreases according to the wavelength of the measuring light, or flat wavelength dispersion characteristics in which the phase difference value hardly changes with the wavelength of the measuring light.
[0032] The thickness of the retardation film can be set so that it can optimally function as a λ / 4 plate. In other words, the thickness can be set so that the above-mentioned desired in-plane retardation is obtained. Specifically, the thickness is preferably 70 μm or less, preferably 15 μm to 60 μm.
[0033] like Figure 1As shown in (a), the phase difference film typically has an axial offset in the width direction in the original film roll 10. In more detail, the direction of the slow axis S of the phase difference film is mostly offset by a given angle relative to the length direction of the roll at the width direction end of the roll. Typically, the axial offset is not substantially manifested in the central part, but becomes larger as it approaches the width direction end. The axial offset at the width direction end will change according to the width of the roll. For example, in a roll with a width of about 1000mm to 1500mm, the axial offset at the width direction end can be, for example, 1° to 3°. In the case of making a large (for example, for TV) polarizing film with a phase difference layer, such an axial offset will not become a substantial problem. This is because, by improving the color unevenness and viewing angle dependence of the polarizing film with a phase difference layer as a whole, the problem of axial offset will not surface or worsen. On the other hand, the inventors of the present invention have newly discovered that in the case of making a very small (for example, for VR goggles: a size of about 20mm×30mm) polarizing film with a phase difference layer, the deviation of the characteristics of each final product caused by such an axial offset becomes unacceptably large. Furthermore, the inventors of the present invention have made continuous attempts to solve this problem, and found that the axial deviation of the slow axis of the phase difference film is more dominant than the axial deviation of the absorption axis of the polarizer, and that the problem can be solved by adopting a manufacturing process that appropriately eliminates the axial deviation of the slow axis of the phase difference film, thereby completing the present invention. That is, the embodiment of the present invention can solve a new problem that has not been recognized so far, and the effect is an unexpected excellent effect.
[0034] In an embodiment of the present invention, Figure 1 As shown in (a), the original film roll 10 is punched into a given size while correcting the deviation of the slow axis S in the width direction relative to the length direction, so that Figure 1 As shown in (b), a single-piece (representatively rectangular) phase difference layer intermediate 12 having a slow axis S in the long side direction is obtained. In more detail, it is as follows. First, the axial deviation of the slow axis S of the original film roll 10 is detected. As a method for detecting the axial deviation, any appropriate means can be used. For example, the axial deviation can be detected by measuring the axial angle using "AxoScan" manufactured by Axometrics. When detecting the axial deviation, the direction of the punching knife is adjusted based on the detected information, and the punching knife with the adjusted direction is used to punch a given portion of the original film roll. As a result, as shown in FIG. Figure 1As shown in (b), no matter where the punching position of the original film roll is, a phase difference layer intermediate 12 having a slow axis S in the long side direction (that is, the slow axis direction is precisely controlled) and a very small (substantially no) deviation in the slow axis direction between the intermediates can be obtained. By correcting the axial offset of the slow axis of the original film roll when making the phase difference layer intermediate, the deviation in the slow axis direction between the intermediates is substantially eliminated in the phase difference layer intermediate, thereby making it extremely simple and easy to control the axial direction when making the polarizer intermediate with phase difference layer and the polarizer sheet with phase difference layer (the polarizer with phase difference layer as the final product) described later.
[0035] exist Figure 1 (a) illustrates an example of punching out three phase difference layer intermediates from the original film roll in the width direction, but in an embodiment of the present invention, representatively, 3 to 16 phase difference layer intermediates, and 5 to 6 phase difference layer intermediates, can be punched out from the original film roll in the width direction. If such a structure is used, the manufacturing efficiency is excellent, the waste of the original film roll is small, and the phase difference layer intermediate with the axial deviation of the original film roll properly corrected can be obtained. In this case, the obtained phase difference layer intermediate can be, for example, a rectangle with a short side of about 75mm to 310mm, and can also be, for example, a rectangle with a long side of 250mm to 350mm and a short side of about 150mm to 250mm.
[0036] The punching of the phase difference layer intermediate body may be performed for each sheet while correcting the axis deviation, or may be performed for each row in the width direction while adjusting the directions of a predetermined number of punching blades.
[0037] C. Polarizer intermediate production process
[0038] like Figure 2As shown in (a), separately prepare the original film roll 20 of the polarizer. The polarizer typically has a polarizer and a protective film arranged on at least one side of the polarizer. As the polarizer, any appropriate polarizer can be used. The resin film forming the polarizer can be a single-layer resin film, or it can be made using a laminate of two or more layers. As a specific example of a polarizer composed of a single-layer resin film, there can be cited a polarizer obtained by dyeing and stretching a hydrophilic polymer film such as a polyvinyl alcohol (PVA) resin film, a partially formalized PVA resin film, and a partially saponified film of an ethylene-vinyl acetate copolymer, etc., using iodine, dichroic dyes and other dichroic substances; a polyene oriented film such as a dehydrated product of PVA, a dehydrochlorinated product of polyvinyl chloride, etc. Due to its excellent optical properties, it is preferred to use a polarizer obtained by dyeing a PVA resin film with iodine and uniaxially stretching it. The above-mentioned dyeing with iodine can be performed, for example, by immersing the PVA resin film in an iodine aqueous solution. The stretching ratio of the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching can be performed after dyeing or while dyeing. In addition, dyeing can be performed after stretching. The PVA resin film can be subjected to swelling treatment, cross-linking treatment, cleaning treatment, drying treatment, etc. as required. For example, by immersing the PVA resin film in water and washing it before dyeing, not only can the dirt and anti-blocking agent on the surface of the PVA resin film be cleaned, but also the PVA resin film can be swollen to prevent uneven dyeing.
[0039] As a specific example of a polarizer obtained using a laminate, there can be cited a laminate using a resin substrate and a PVA-type resin layer (PVA-type resin film) laminated on the resin substrate, or a polarizer obtained using a laminate using a resin substrate and a PVA-type resin layer formed by coating on the resin substrate. The polarizer obtained using a laminate using a resin substrate and a PVA-type resin layer formed by coating on the resin substrate can be made by the following method: for example, a PVA-type resin solution is applied to a resin substrate, and the PVA-type resin layer is formed on the resin substrate by drying, thereby obtaining a laminate of the resin substrate and the PVA-type resin layer; the laminate is stretched and dyed to make the PVA-type resin layer into a polarizer. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. In addition, stretching may further include stretching the laminate in a gas atmosphere at a high temperature (for example, above 95°C) before stretching in an aqueous boric acid solution, as needed. The obtained laminate of resin substrate / polarizer can be used directly (that is, the resin substrate can be made into a protective layer of polarizer), or the resin substrate can be peeled off from the laminate of resin substrate / polarizer, and any appropriate protective layer corresponding to the purpose can be laminated on the peeled surface for use. The details of the manufacturing method of such a polarizer are described in, for example, Japanese Patent Publication No. 2012-73580 and Japanese Patent No. 6470455. The descriptions of these patent documents are cited in this specification as reference.
[0040] The protective film can be made of any suitable film that can be used as a protective film for a polarizer. As a specific example of the material that becomes the main component of the film, cellulose resins such as triacetyl cellulose (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyether sulfones, polysulfones, polystyrenes, polynorbornenes, polyolefins, cyclic olefins, (meth) acrylic acid, transparent resins such as acetates, etc. can be cited. In addition, thermosetting resins or ultraviolet curing resins such as (meth) acrylic acid, carbamates, (meth) acrylic acid carbamates, epoxies, silicones, etc. can also be cited. In addition, glassy polymers such as siloxane polymers can also be cited. In addition, the polymer film described in Japanese Patent Publication No. 2001-343529 (WO01 / 37007) can also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl and nitrile group in the side chain can be used, and for example, a resin composition having an alternating copolymer formed by isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer can be mentioned. The polymer film can be, for example, an extrusion molding of the above resin composition. TAC, (meth) acrylic resin, and cyclic olefin resin can be preferably used.
[0041] like Figure 2 As shown in (a), representatively, the polarizer has substantially no axial offset in the width direction in the original film roll 20. In more detail, for the polarizer, due to the material, optical properties, manufacturing method, etc., the direction of its absorption axis A in the width direction of the original film roll as a whole will appear as a direction substantially parallel to the length direction of the original film roll. That is, the axial offset of the absorption axis of the polarizer in the width direction does not substantially exist, or even if it exists, it is very small relative to the axial offset of the slow axis of the phase difference film. Therefore, when making the polarizer intermediate 22 from the original film roll 20 of the polarizer, it is not necessary to perform punching while correcting the axial offset. As a result, in an embodiment of the present invention, by using, for example, a lattice-shaped punching knife, it is possible to Figure 2 As shown in (b), a plurality of polarizing plate intermediates are punched out at once. In the example shown in the figure, by punching out in a direction of 45° relative to the longitudinal direction of the original film roll, Figure 2 As shown in (c), a single (representatively rectangular) polarizer intermediate 22 having an absorption axis A in a direction of 45° relative to the long side direction is obtained. By punching out a plurality of polarizer intermediates in this way, excellent manufacturing efficiency can be achieved. In addition, if each sheet is punched out in an inclined direction (in a direction at a given angle relative to the length direction of the original film roll), sometimes even if there is no axial deviation in the original film roll, there will be axial deviations between the punched-out intermediates, and such problems can be avoided by punching out together. That is, a polarizer intermediate 22 in which the absorption axis direction is precisely controlled and the deviation in the absorption axis direction between the intermediates is very small (substantially no deviation) can be obtained. It should be noted that the punching angle (angle relative to the length direction of the original film roll) can be appropriately set according to the purpose in addition to 45°, which is obvious to those skilled in the art. This angle is equivalent to the angle between the absorption axis of the polarizer in the polarizer with a phase difference layer and the slow axis of the phase difference layer.
[0042] The above-mentioned oblique punching can be typically performed as follows: the edge in the width direction of the original film roll is detected, the direction of the punching blade is adjusted based on the detected information, and the punching is performed with the punching blade with the adjusted direction.
[0043] The size of the punched polarizer intermediate is typically the same as the size of the phase difference layer intermediate. Therefore, the obtained polarizer intermediate can be, for example, a rectangle with a short side of about 75mm to 310mm, and can also be, for example, a rectangle with a long side of 250mm to 350mm and a short side of about 150mm to 250mm. If it is such a structure, as described later, the preparation of the polarizer intermediate with a phase difference layer is simple and easy, and the absorption axis of the polarizer in the polarizer intermediate with a phase difference layer and the angle of the slow axis of the phase difference layer (phase difference film) are easy to control.
[0044] D. Production process of polarizing plate intermediate with phase difference layer
[0045] Next, if Figure 3 As shown in (a), the phase difference layer intermediate 12 obtained as described in the above item B is bonded with the polarizer intermediate 22 obtained as described in the above item C to obtain a polarizer intermediate with a phase difference layer. The phase difference layer intermediate and the polarizer intermediate are typically bonded in a manner that makes their respective outer edges consistent. As described above, the phase difference layer intermediate and the polarizer intermediate are both precisely controlled in the axial direction, and the axial deviation between each intermediate is very small. Therefore, by bonding in a manner that makes their respective outer edges consistent, the angle between the absorption axis of the polarizer in the polarizer intermediate with a phase difference layer and the slow axis of the phase difference layer can be well controlled without precise and / or delicate operations. In addition, there is no doubt that such an operation is simple and easy, and therefore, the preparation of the polarizer intermediate with a phase difference layer is simple and easy in itself. In this way, a polarizer intermediate with a phase difference layer can be obtained in which the phase difference layer has a slow axis in the long side direction and the angle between the absorption axis of the polarizer and the slow axis of the phase difference layer is 45°.
[0046] E. Final process
[0047] Next, if Figure 3 (b) and Figure 3 As shown in (c), the polarizer intermediate 30 with a phase difference layer obtained as described in the above item D is punched out to obtain a polarizer sheet with a phase difference layer (a polarizer with a phase difference layer as a final product) 32. Punching is typically performed in a direction of 45° relative to the long side direction of the polarizer intermediate with a phase difference layer. As a result, Figure 3 As shown in (c), a polarizer sheet with a phase difference layer can be obtained, in which the polarizer has an absorption axis in the long side direction and the angle between the absorption axis of the polarizer and the slow axis of the phase difference layer is 45° (a polarizer with a phase difference layer as a final product). As described above, in the polarizer intermediate with a phase difference layer, the angle between the absorption axis of the polarizer and the slow axis of the phase difference layer is well controlled. Therefore, when making a polarizer sheet 32 with a phase difference layer from the polarizer intermediate 30 with a phase difference layer, it is not necessary to perform punching while correcting the axis offset. As a result, in an embodiment of the present invention, by using, for example, a lattice-shaped punching knife, Figure 3(b) As shown, multiple polarizer sheets with phase difference layers are punched out at the same time. By punching out multiple polarizer sheets with phase difference layers at the same time like this, excellent manufacturing efficiency can be achieved. In addition, if each sheet is punched out in an inclined direction (in a direction at a given angle relative to the long side direction of the polarizer intermediate with a phase difference layer), sometimes even if there is no axial offset in the polarizer intermediate with a phase difference layer, axial deviations will occur between the punched out final products, and such problems can be avoided by punching out together. That is, a polarizer sheet 32 with a phase difference layer can be obtained in which the absorption axis direction and the slow axis direction are precisely controlled and these deviations between each product are very small (substantially no deviation).
[0048] The above-mentioned oblique direction punching can be typically performed as follows: the edge of the polarizer intermediate with a phase difference layer is detected, and the direction of the punching knife is adjusted based on the detected information, and the punching knife with the adjusted direction is used for punching. Preferably, the two edges of the long side and the short side of the polarizer intermediate with a phase difference layer are detected. If it is such a structure, more precise punching can be performed.
[0049] In this way, a polarizer sheet with a phase difference layer (a polarizer with a phase difference layer as a final product) 32 can be obtained. The obtained polarizer sheet with a phase difference layer can be, for example, a long side of 10 mm to 70 mm and a short side of about 10 mm to 70 mm, and can also be, for example, a long side of 20 mm to 40 mm and a short side of about 10 mm to 30 mm, and more specifically, a rectangle with a long side of 30 mm and a short side of about 20 mm. Such a polarizer sheet with a phase difference layer can be used, for example, as a circular polarizer for VR goggles.
[0050] According to an embodiment of the present invention, by adopting a manufacturing process completely different from the past, a polarizer with a phase difference layer in which the absorption axis direction of the polarizer and the slow axis direction of the phase difference layer are extremely precisely controlled can be effectively manufactured. In particular, the effect is significant in the manufacture of very small polarizers with phase difference layers. Specifically, as described below. In the previous manufacturing method, typically, the phase difference film is punched out from the original film roll of the phase difference film in a direction inclined relative to the length direction of the original film roll (for example, a 45° direction), and the polarizer is punched out from the original film roll of the polarizer along the length direction of the original film roll. This is because the yield rate becomes higher when operating like this, and the problem of axial deviation of the phase difference layer (phase difference film) in the polarizer with a phase difference layer of the previous size will not be aggravated. On the other hand, in the case of making a very small polarizer with a phase difference layer (for example, for VR goggles: a size of about 20mm×30mm), if the manufacturing method is as described above, there is a situation where the deviation of the characteristics between each final product becomes unacceptably large. According to an embodiment of the present invention, by punching out a phase difference film from the original film roll of the phase difference film while correcting the axis offset, and punching out a polarizer from the original film roll of the polarizer in a direction inclined relative to the length direction of the original film roll (for example, a 45° direction), even if a very small polarizer with a phase difference layer is finally produced, a polarizer with a phase difference layer in which the absorption axis direction of the polarizer and the slow axis direction of the phase difference layer are extremely precisely controlled can be obtained. In this case, the discarded portion of the original film roll is more than that of the previous manufacturing method, but the number of unacceptable final products is overwhelmingly reduced, so the overall yield rate sometimes becomes higher. Alternatively, even in the case where the overall yield rate is reduced, since the axis offset of the polarizer with a phase difference layer cannot be detected without destroying the final product (for example, VR goggles), it is useful as a quality assurance of the final product.
[0051] Industrial Applicability
[0052] The production method according to the embodiment of the present invention can be suitably used for the production of a polarizing plate with a retardation layer, and is particularly suitably used for the production of a very small polarizing plate with a retardation layer (for example, for VR goggles).
Claims
1. A method for manufacturing a polarizing plate with a phase difference layer, the method comprising: A phase difference film roll having a slow axis in the longitudinal direction is punched into a given size while correcting the deviation of the slow axis in the width direction of the original film roll relative to the longitudinal direction, thereby obtaining a single-piece phase difference layer intermediate having a slow axis in the long side direction; Punching the original film roll of the polarizer having an absorption axis in the longitudinal direction into the same size as the phase difference layer intermediate to obtain a single polarizer intermediate having an absorption axis in a direction of 45° relative to the longitudinal direction; The phase difference layer intermediate and the polarizing plate intermediate are bonded together so that the outer edges are aligned, thereby obtaining a polarizing plate intermediate with a phase difference layer in which the angle between the absorption axis of the polarizing plate and the slow axis of the phase difference layer is 45°; and The intermediate product of the polarizing plate with a retardation layer is punched out to obtain a polarizing plate sheet with a retardation layer of a predetermined size having an absorption axis in the longitudinal direction.
2. The manufacturing method according to claim 1, comprising: From the original film roll of the retardation film, 3 to 16 sheets of the retardation layer intermediate are obtained in the width direction.
3. The manufacturing method according to claim 1 or 2, wherein: The phase difference layer intermediate and the polarizing plate intermediate are rectangular with a short side of 75 mm to 310 mm.
4. The manufacturing method according to claim 3, wherein: The polarizing sheet with a phase difference layer is rectangular with a long side of 10 mm to 70 mm and a short side of 10 mm to 70 mm.