CN116635761A - Polarizing plate after curved surface processing and method for manufacturing the same - Google Patents
Polarizing plate after curved surface processing and method for manufacturing the same Download PDFInfo
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- CN116635761A CN116635761A CN202180074832.6A CN202180074832A CN116635761A CN 116635761 A CN116635761 A CN 116635761A CN 202180074832 A CN202180074832 A CN 202180074832A CN 116635761 A CN116635761 A CN 116635761A
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
- G02B1/14—Protective coatings, e.g. hard coatings
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133528—Polarisers
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/80—Constructional details
- H10K59/8793—Arrangements for polarized light emission
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- Crystallography & Structural Chemistry (AREA)
- Polarising Elements (AREA)
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Abstract
The invention provides a polarizing plate which can inhibit uneven display and decoloration even though the polarizing plate is subjected to curved surface processing and is suitable for an image display device. The polarizing plate according to an embodiment of the present invention includes a polarizer and a protective layer disposed on at least one side of the polarizer, and the polarizing plate is subjected to a curved surface process and is subjected to a humidification process for 40 minutes or more in an environment of 40 to 65 ℃ and 85 to 95% RH after the curved surface process, and the polarizing plate satisfies the following relationship: ts (Ts) R －Ts 0 ＝ΔTs≤+1.5(％)；P R －P 0 ＝ΔP≥‑1.5(％)；‑2.0(nm)≤Re R －Re 0 =Δre+.2.0 (nm), where Ts 0 Is the transmittance of the monomer before the curved surface processing, ts R The transmittance of the monomer after humidification treatment; p (P) 0 For degree of polarization before curved surface processing, P R The polarization degree after humidification treatment; re (Re) 0 Re is the in-plane retardation before the curved surface processing R Is the in-plane phase difference after the humidification treatment.
Description
Technical Field
The present invention relates to a polarizing plate after curved surface processing and a method for manufacturing the same.
Background
In image display devices such as liquid crystal display devices and organic Electroluminescence (EL) display devices, polarizing plates have been widely used for the purpose of realizing image display and/or improving the performance of the image display. Curved surface processing may be required for the polarizing plate depending on the application. Curved processing typically involves shaping the polarizer into a given shape in a high temperature environment. However, the polarizing plate after the curved surface processing has a problem that display unevenness and/or discoloration occur in the case of being applied to an image display device.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 8-136731
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made to solve the above-described conventional problems, and a main object of the present invention is to provide a polarizing plate capable of suppressing display unevenness and discoloration even when the polarizing plate is applied to an image display device, despite being subjected to a curved surface processing, and a simple manufacturing method thereof.
Means for solving the problems
The polarizing plate according to an embodiment of the present invention includes a polarizer and a protective layer disposed on at least one side of the polarizer, and the polarizer is subjected to a curved surface process and is subjected to a humidification process for 40 minutes or more in an environment of 40 to 65 ℃ and 85 to 95% rh after the curved surface process, and the polarizing plate satisfies the following relationship:
Ts R －Ts 0 ＝ΔTs≤+1.5(％)
P R －P 0 ＝ΔP≥-1.5(％)
-2.0(nm)≤Re R －Re 0 ＝ΔRe≤+2.0(nm)
wherein Ts 0 Is the transmittance of the monomer before the curved surface processing, ts R The transmittance of the monomer after humidification treatment; p (P) 0 For degree of polarization before curved surface processing, P R The polarization degree after humidification treatment; re (Re) 0 Re is the in-plane retardation before the curved surface processing R Is the in-plane phase difference after the humidification treatment.
In one embodiment, 9 Re measured in each region of the region where the curved surface processing portion of the polarizing plate is divided into a lattice shape 9 is defined R The difference between the maximum value and the minimum value of (2) is 3.0nm or less.
According to another aspect of the present invention, there is provided a method for producing a polarizing plate having been subjected to a curved surface processing. The manufacturing method comprises the following steps: preparing a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer; heating the polarizer together with a mold having a predetermined curved shape to perform curved surface processing; and humidifying the curved polarizer in an environment of 40-65 ℃ and 85-95%RH for more than 40 minutes.
In one embodiment, the heating temperature in the curved surface processing is 100 ℃ or higher.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the embodiment of the present invention, by subjecting the polarizing plate after the curved surface processing to a given humidification treatment, a polarizing plate capable of suppressing display unevenness and discoloration in the case of being applied to an image display device can be realized.
Drawings
Fig. 1 is a schematic perspective view of a polarizing plate according to an embodiment of the present invention.
Fig. 2 is a schematic cross-sectional view of the polarizer of fig. 1.
Fig. 3 (a) to 3 (c) are schematic views for explaining an example of a method for manufacturing a curved polarizer according to an embodiment of the present invention.
Symbol description
10. Polarizer
20. Protective layer
30. Protective layer
100. Polarizing plate
Detailed Description
Hereinafter, representative embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. The drawings are schematically drawn for the convenience of observation, and the shape, thickness, radius of curvature, and the like thereof are different from those of actual ones, and there are also differences between the drawings.
A. Polarizing plate
A-1 integral construction of polarizer
FIG. 1 is a schematic perspective view of a polarizer according to an embodiment of the present invention; fig. 2 is a schematic cross-sectional view of the polarizer of fig. 1. The polarizer 100 of the illustrated example is subjected to a curved surface process. In other words, the polarizing plate is a polarizing plate in which temporary deterioration of characteristics (typically, optical characteristics, chemical characteristics, and mechanical characteristics) occurs due to curved surface processing (i.e., in a high-temperature environment). According to the embodiment of the present invention, the polarizing plate having the temporarily deteriorated characteristics can be subjected to a humidification process described later, whereby the characteristics can be recovered. As a result, when the curved polarizing plate is applied to an image display device, display unevenness and discoloration can be suppressed. The curved surface processing temperature may be, for example, 100 ℃ or higher, 120 ℃ or higher, 140 ℃ or higher, or 160 ℃ or higher, for example. The upper limit of the surface processing temperature may be 200 ℃. The curved surface processing time may be, for example, 15 seconds to 5 minutes.
As the shape of the curved surface processing, any appropriate shape according to the purpose can be adopted. Specific examples of the curved surface processing shape include a dome shape and a semi-conical shape as shown in fig. 1. Examples of the polarizer subjected to such a curved surface processing include: the polarizing plate is applicable to a curved image display device. Examples of the curved image display device include: virtual Reality (VR) goggles, digital signage provided to curved walls, posts. The polarizing plate illustrated in the drawings is convex toward the visible side, but the polarizing plate may be convex toward the side opposite to the visible side depending on the purpose.
The polarizing plate 100 typically includes: the polarizer 10, a protective layer 20 disposed on one side (the visible side in the illustrated example) of the polarizer, and a protective layer 30 disposed on the other side. Any of the protective layers 20 or 30 may be omitted depending on the purpose. In the present specification, the protective layer 20 may be referred to as a visible side protective layer, and the protective layer 30 may be referred to as an inner side protective layer.
In the embodiment of the present invention, typically, the polarizing plate is subjected to a humidification treatment (substantially, a heating/humidification treatment) after the curved surface processing. In the embodiment of the present invention, by applying the curved-surface-processed polarizing plate to the heating/humidifying treatment, the optical characteristics of the polarizing plate (substantially, polarizing plate) are recovered, and when the polarizing plate is applied to an image display device, display unevenness and discoloration can be suppressed. The effect brought about by such heating/humidifying treatment is an unexpected excellent effect. Details are as follows. The heating/humidifying treatment is generally performed in the form of a durability test of the polarizing plate. The conventional polarizing plate is subjected to heating/humidifying treatment on the premise that the optical characteristics of the polarizing plate are deteriorated (the degree of deterioration is used as an index of durability). In other words, it is common knowledge in the art that the optical characteristics of the polarizing plate may be deteriorated due to the heating/humidifying treatment. On the other hand, the present inventors have found that the deteriorated characteristics can be recovered by applying a polarizing plate, which is temporarily deteriorated in characteristics in a high-temperature environment (for example, by a curved surface process), to a heating/humidifying treatment. That is, the heating/humidifying treatment in the embodiment of the present invention is completed based on the technical ideas contrary to the conventional knowledge in the art, and the effect thereof is an unexpected excellent effect. The heating temperature in the heating/humidifying treatment is preferably 40 to 65 ℃, more preferably 55 to 65 ℃, still more preferably 57 to 63 ℃, particularly preferably 58 to 62 ℃, and particularly preferably about 60 ℃. Either too high or too low a heating temperature may result in insufficient recovery of the properties. The humidity in the heating/humidifying treatment is preferably 85% RH to 95% RH, more preferably 87% RH to 93% RH, still more preferably 88% RH to 92% RH, and particularly preferably about 90% RH. Too high or too low humidity may result in insufficient recovery of the properties. The treatment time is preferably 40 minutes or longer, more preferably 50 minutes or longer, still more preferably 1 hour or longer, and particularly preferably 2 hours or longer. The upper limit of the treatment time may be, for example, 5 hours. When the treatment time is too short, the characteristics may not be sufficiently recovered. On the other hand, too long a treatment time is sometimes inefficient because the effect obtained is not substantially changed even if the treatment time is excessively prolonged.
In an embodiment of the present invention, the polarizing plate satisfies the following relationship:
Ts R －Ts 0 ＝ΔTs≤+1.5(％)
P R －P 0 ＝ΔP≥-1.5(％)
-2.0(nm)≤Re R －Re 0 ＝ΔRe≤+2.0(nm)
wherein Ts 0 Is the transmittance of the monomer before the curved surface processing, ts R The transmittance of the monomer after humidification treatment; p (P) 0 For degree of polarization before curved surface processing, P R The polarization degree after humidification treatment; re (Re) 0 Re is the in-plane retardation before the curved surface processing R Is the in-plane phase difference after the humidification treatment. By satisfying such a relationship with the polarizing plate, when the polarizing plate is applied to an image display device, display unevenness and discoloration can be suppressed. Δts is preferably-2.0% to +1.5%, more preferably-1.8% to +1.3%, and still more preferably-1.5% to +1.0%. Δp is preferably-1.2% or more, more preferably-1.0% or more, and still more preferably-0.8% to 0.0%. ΔRe is preferably-1.0 nm to +2.0nm, more preferably-0.8 nm to +1.8nm. As described above, according to the embodiment of the present invention, the optical characteristics of the polarizing plate temporarily deteriorated by the curved surface processing can be restored to the same level as before the curved surface processingAnd the like. As a result, even though the polarizing plate is subjected to the curved surface processing, display unevenness and discoloration can be suppressed in the case of being applied to an image display device. Re, re R Re and Re 0 The in-plane retardation of the entire polarizer is corrected by excluding the influence of the polarizer after the entire polarizer is measured. When the thickness of the film is d (nm), re can be represented by the formula: re= (nx-ny) x d. nx is a refractive index in a direction in which the refractive index in the plane reaches the maximum (i.e., a slow axis direction), and ny is a refractive index in a direction orthogonal to the slow axis in the plane (i.e., a fast axis direction). Re (Re) R Re and Re 0 For example, the measurement wavelength of (C) may be 550nm.
In one embodiment, 9 Re measured in each region of the region where the curved surface processing portion of the polarizing plate is divided into the grid 9 is defined R The difference between the maximum value and the minimum value (hereinafter, sometimes referred to as a phase difference deviation) is preferably 3.0nm or less, more preferably 2.5nm or less, and still more preferably 2.0nm or less. The smaller the phase difference deviation is, the more preferably, the lower limit is desirably zero, and may be, for example, 0.1nm.
Hereinafter, the polarizer and the protective layer will be specifically described.
A-2 polarizer
Typically, the polarizer is formed of a resin film containing a dichroic substance (e.g., iodine, dichroic dye). As the resin film, any suitable resin film that can be used as a polarizer can be used. Typically, the resin film is a polyvinyl alcohol resin (hereinafter referred to as "PVA-based resin") film. The resin film may be a single-layer resin film or a laminate of two or more layers.
As a specific example of a polarizer composed of a single-layer resin film, a polarizer obtained by subjecting a PVA-based resin film to a dyeing treatment with iodine and a stretching treatment (typically, unidirectional stretching) is cited. The dyeing with iodine can be performed, for example, by immersing the PVA-based film in an aqueous iodine solution. The stretching ratio of the unidirectional stretching is preferably 3 to 7 times. Stretching may be performed after dyeing treatment or may be performed while dyeing. In addition, dyeing may be performed after stretching. The PVA-based resin film may be subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, and the like as needed. For example, by immersing the PVA-based resin film in water before dyeing and washing with water, not only dirt and an anti-blocking agent on the surface of the PVA-based film can be washed off, but also the PVA-based resin film can be swelled to prevent uneven dyeing and the like.
Specific examples of the polarizer obtained using the laminate include: a polarizer obtained by using a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or by using a laminate of a resin base material and a PVA-based resin layer formed on the resin base material by coating. A polarizer obtained by using a laminate of a resin base material and a PVA-based resin layer formed on the resin base material, can be produced by the following method: for example, a PVA-based resin solution is applied to a resin substrate, and dried to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer; the laminate was stretched and dyed to prepare a polarizer from the PVA-based resin layer. In the present embodiment, it is preferable to form a polyvinyl alcohol resin layer containing a halide and a polyvinyl alcohol resin on one side of the resin base material. Stretching typically includes immersing the laminate in an aqueous boric acid solution to stretch the laminate. Further, the stretching may further include stretching the laminate in a gas atmosphere at a high temperature (for example, 95 ℃ or higher) before stretching in an aqueous boric acid solution, as needed. In the present embodiment, it is preferable that the laminate is subjected to a drying shrinkage treatment in which the laminate is heated while being conveyed in the longitudinal direction and is shrunk by 2% or more in the width direction. Typically, the manufacturing method of the present embodiment includes sequentially subjecting the laminate to an auxiliary stretching treatment in a gas atmosphere, a dyeing treatment, an aqueous stretching treatment, and a drying shrinkage treatment. By introducing the auxiliary stretching, even when PVA is coated on the thermoplastic resin, crystallinity of PVA can be improved, and high optical characteristics can be achieved. Further, by simultaneously improving the orientation of PVA in advance, problems such as lowering and dissolution of the orientation of PVA can be prevented when immersed in water in the subsequent dyeing step and stretching step, and high optical characteristics can be achieved. In addition, when the PVA-based resin layer is immersed in a liquid, disorder of alignment and decrease of alignment property of the polyvinyl alcohol molecules can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide. This can improve the optical characteristics of the polarizer obtained by the treatment step of immersing the laminate in a liquid, such as dyeing treatment or stretching treatment in an aqueous solution. Further, the laminate is shrunk in the width direction by the drying shrinkage treatment, whereby the optical characteristics can be improved. The resulting laminate of the resin substrate and the polarizer may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the laminate of the resin substrate and the polarizer, and any appropriate protective layer suitable for the purpose may be laminated on the peeled surface. Details of such a method for manufacturing a polarizer are described in, for example, japanese patent application laid-open No. 2012-73580, and japanese patent No. 6470455. The entire disclosures of these publications are incorporated by reference into this specification.
As the thickness of the polarizer, any appropriate thickness may be used according to the purpose. The thickness of the polarizer is, for example, 35 μm or less, preferably 20 μm or less, more preferably 15 μm or less, still more preferably 12 μm or less, particularly preferably 10 μm or less, still more preferably 8 μm or less, particularly preferably 6 μm or less, and most preferably 5 μm or less. The lower limit of the thickness of the polarizer is preferably 2 μm, more preferably 1 μm.
Initial polarization degree (polarization degree before curved surface processing) P of polarizer 0 Preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more. Initial monomer transmittance (monomer transmittance before surface processing) Ts of polarizer 0 Preferably 40.0% to 46.0%, more preferably 41.0% to 43.5%.
A-3 protective layer
The visible side protective layer and the inner protective layer may be formed of any appropriate film that can be used as the protective layer of the polarizer. Specific examples of the material that becomes the main component of the film include: cellulose resins such as cellulose Triacetate (TAC), transparent resins such as polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, polysulfones, polystyrenes, polynorbornenes, polyolefins, (meth) acrylic acids, and acetates, and the like. In addition, there may be mentioned: and thermosetting resins such as (meth) acrylic, urethane, (meth) acrylic urethane, epoxy, and silicone resins, ultraviolet curable resins, and the like. In addition, glass polymers such as siloxane polymers can be used. In addition, a polymer film described in Japanese patent application laid-open No. 2001-343529 (WO 01/37007) can also be used. As a material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain can be used, and examples thereof include: a resin composition having an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extrusion molded product of the above resin composition.
The inner protective layer is preferably optically isotropic. In the present specification, "optically isotropic" means that the in-plane retardation Re (550) (before the curved surface processing) is 0nm to 10nm, and the retardation Rth (550) in the thickness direction is-10 nm to +10nm. Here, "Rth (λ)" is a phase difference in the thickness direction measured at 23 ℃ with light having a wavelength of λnm. For example, "Rth (550)" is a phase difference in the thickness direction measured at 23℃with light having a wavelength of 550nm. Assuming that the thickness of the layer (film) is d (nm), rth (λ) can be represented by the formula: rth (λ) = (nx-nz) ×d. nz is the refractive index in the thickness direction.
When the polarizing plate is disposed on the visible side of the image display device, a surface treatment such as a hard coat treatment, an antireflection treatment, an anti-blocking treatment, or an antiglare treatment may be applied to the visible side protective layer as necessary. Further, the visible side protective layer may be subjected to a process (typically, a process of imparting (elliptical) polarization function, a process of imparting ultra-high phase difference) as needed to improve visibility when viewing through polarized sunglasses.
The thickness of the protective layer may be any suitable thickness. The thickness of the protective layer is, for example, 10 μm to 90 μm, preferably 20 μm to 80 μm, more preferably 20 μm to 60 μm, still more preferably 20 μm to 40 μm. When the surface treatment is performed, the thickness of the protective layer includes the thickness of the surface treatment layer.
B. Method for manufacturing polarizing plate
The polarizing plate described in item a above is typically one whose characteristics are recovered by a humidification treatment after a curved surface processing. Accordingly, embodiments of the present invention also include a method of manufacturing a polarizing plate including a curved surface processing and a humidifying treatment. Fig. 3 (a) to 3 (c) are schematic views for explaining an example of a method for manufacturing a curved-surface-processed polarizing plate according to an embodiment of the present invention.
In the manufacturing method according to the embodiment of the present invention, first, as shown in fig. 3 (a), a polarizing plate 100' including a polarizer and a protective layer disposed on at least one side of the polarizer is prepared. Meanwhile, as shown in fig. 3 (a), a mold 200 having a given curved shape (dome shape in the illustrated example) is also prepared.
Next, in one embodiment, as shown in fig. 3 (b), the polarizing plate 100' is attached to the mold 200. The attachment of the polarizer 100' to the mold 200 may be performed in any suitable manner. In the example shown in the figure, the polarizing plate 100' may be attached to the mold 200 via an adhesive, for example. Next, the polarizing plate 100' is heated in a state of being bonded to the mold 200, and the polarizing plate is subjected to curved surface processing (molding). In another embodiment, not shown, the polarizer 100' is heated to a curved surface processing temperature in a vacuum state in a state where it is placed on the mold 200, and after the curved surface processing temperature is reached, the system is opened, and the curved surface processing (molding) is performed under air pressure (atmospheric pressure). The surface processing temperature is as described in item A above.
Next, the polarizing plate after the curved surface processing is subjected to humidification processing. The humidification treatment may be performed directly while the polarizing plate is bonded to the mold, or may be performed after the polarizing plate is detached from the mold as shown in fig. 3 (c). The conditions of the humidification processing are as described in item a above. In this way, the polarizer 100 after the curved surface processing can be obtained.
Examples
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The evaluation items in the examples are as follows. Unless otherwise specifically noted, the "parts" and "%" in the examples are based on weight.
(1) Monomer transmittance and degree of polarization
The polarizers used in examples and comparative examples were measured for the transmittance and polarization degree of each of the monomers before and after the curved surface was formed into a dome shape. Specifically, for each polarizer, the individual transmittance Ts, the parallel transmittance Tp, and the orthogonal transmittance Tc were measured using an ultraviolet-visible spectrophotometer (LPF-200, manufactured by large-scale electronics corporation) as polarizers Ts, tp, and Tc, respectively. These Ts, tp, and Tc are Y values obtained by measuring a 2-degree field of view (C light source) of JIS Z8701 and correcting the sensitivity.
The polarization degree P was obtained from Tp and Tc obtained by the following equation.
Degree of polarization P (%) = { (Tp-Tc)/(tp+tc) } 1/2 ×100
Let the transmittance of the monomer before the curved surface processing be Ts 0 The transmittance of the monomer after the curved surface processing is set as Ts R The polarization degree before the curved surface processing is set as P 0 The polarization degree after the curved surface processing is set as P R 。
The polarizer after the curved surface processing was performed as follows: the regions (1 region size: 15 mm. Times.15 mm) divided in a lattice shape 9 were defined except for the lower end portion of the dome-shaped polarizing plate, and each region was measured, and the maximum value was defined as Ts for the individual transmittance R Regarding the degree of polarization, the minimum value is set to P R . The dome-shaped polarizing plate was fixed by a sample holder, and the dome-shaped polarizing plate was positioned so that each region could be accurately measured. The Ts and P of the polarizer are substantially governed by the characteristics of the polarizer.
(2) In-plane phase difference
The polarizing plates used in examples and comparative examples were measured for the in-plane retardation before and after the curved surface was formed into a dome shape. Specifically, the in-plane retardation was measured for each polarizer using a retardation measuring apparatus (product name "KOBRA-WPR") manufactured by prince measuring instruments. The in-plane phase difference was measured at a wavelength of 550nm and at a temperature of 23 ℃. The measurement of the polarizer after the curved surface processing was performed in the same manner as in (1) above. In order to improve measurement accuracy, measurement was performed in a state where λ/4 plates were superimposed on each polarizing plate. The lambda/4 plate is superimposed on the polarizer with its slow axis at an angle of 45 deg. to the absorption axis of the polarizer. The in-plane phase difference before the curved surface processing is set as Re 0 The in-plane retardation after the curved surface processing is set as Re R 。
(3) Appearance of
The polarizers obtained in examples and comparative examples after the curved surface processing were visually observed for appearance when they were disposed in a state of being crossed with respect to a standard polarizer, and evaluated according to the following criteria.
O: no unevenness or discoloration was observed
Delta: unevenness is observed
X: discoloration is observed
Example 1 >
1. Manufacture of polarizer
An amorphous isophthalic acid copolymerized polyethylene terephthalate film (thickness: 100 μm) having a long shape and a Tg of about 75 ℃ was used as the thermoplastic resin base material, and one side of the resin base material was subjected to corona treatment.
To 100 parts by weight of a PVA based resin obtained by mixing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (trade name "GOHSEFIMER" manufactured by Nippon chemical industries Co., ltd.) at a ratio of 9:1, 13 parts by weight of potassium iodide was added, and the obtained mixture was dissolved in water to prepare a PVA aqueous solution (coating liquid).
The PVA aqueous solution was applied to the corona treated surface of the resin substrate, and dried at 60 ℃ to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.
The resulting laminate was uniaxially stretched to 2.4 times in the machine direction (longitudinal direction) in an oven at 130 ℃.
Next, the laminate was immersed in an insolubilization bath (an aqueous boric acid solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40 ℃ for 30 seconds (insolubilization treatment).
Next, in a dyeing bath (aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with respect to 100 parts by weight of water) at a liquid temperature of 30 ℃, the concentration was adjusted so that the monomer transmittance (Ts) of the final polarizer became a predetermined value, and the resulting polarizer was immersed for 60 seconds (dyeing treatment).
Then, the resultant solution was immersed in a crosslinking bath (an aqueous boric acid solution obtained by mixing 100 parts by weight of water with 3 parts by weight of potassium iodide and 5 parts by weight of boric acid) at a liquid temperature of 40℃for 30 seconds (crosslinking treatment).
Then, while immersing the laminate in an aqueous boric acid solution (boric acid concentration 4 wt% and potassium iodide concentration 5 wt%) at a liquid temperature of 70 ℃, unidirectional stretching (stretching treatment in an aqueous solution) was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio became 5.5 times.
Then, the laminate was immersed in a washing bath (aqueous solution obtained by mixing 100 parts by weight of water with 3 parts by weight of potassium iodide) at a liquid temperature of 20 ℃ (washing treatment).
Then, drying was performed in an oven maintained at about 90 ℃ while being brought into contact with a heated roller made of SUS whose surface temperature was maintained at about 75 ℃ (drying shrinkage treatment).
In this way, a polarizer was formed on the resin substrate, and a laminate having a structure of the resin substrate/polarizer was obtained.
2. Manufacture of polarizer
An acrylic resin film (thickness 40 μm) as a visible side protective layer was bonded to the surface of the polarizer (the surface opposite to the resin base) of the laminate obtained above via an ultraviolet curable adhesive. Specifically, the cured adhesive was applied so that the total thickness of the cured adhesive became about 1.0 μm, and bonded by using a rolling mill. Then, UV light is irradiated from the acrylic resin film side to cure the adhesive. Next, the resin substrate was peeled off to obtain a polarizing plate having a structure of an acrylic resin film (visible side protective layer)/polarizer.
3. Curved surface processing of polarizer
The obtained polarizing plate was punched out into a single sheet, and each was curved (formed) into dome shapes having radii of curvature of 48mm, 65mm and 105 mm. Specifically, the punched polarizing plate was placed on a dome-shaped mold having each radius of curvature, heated to 100 ℃ in a vacuum state, and after the completion, the system was opened, and subjected to curved surface processing (molding) under air pressure (atmospheric pressure). The substantial processing time (pressing time) was 150 seconds. Next, the curved polarizing plate was put into a chamber set to 65 ℃ and 95% rh for 2 hours, and subjected to heating and humidification treatment. In this way, a polarizer after being subjected to curved surface processing was obtained. The obtained polarizing plate was subjected to the evaluations (1) to (3). The results are shown in Table 1.
Example 2 >
A polyvinyl alcohol film (VF-PS 7500, manufactured by Kyowa Co., ltd.) having a thickness of 75 μm was used, immersed in pure water at 30℃for 60 seconds and stretched to a stretching ratio of 2.5 times, stained in an aqueous iodine solution (weight ratio: pure water/iodine (I)/potassium iodide (KI) =100/0.01/1) at 30℃for 45 seconds, stretched in an aqueous 4 wt% boric acid solution to a total stretching ratio of 5.8 times, immersed in pure water for 10 seconds, and then dried at 60℃for 3 minutes while maintaining the film tension, whereby a polarizer (thickness 28 μm) was obtained.
A cellulose Triacetate (TAC) film (thickness 47 μm) as a visible side protective layer was bonded to one surface of the obtained polarizer, and an acrylic resin film (thickness 30 μm) as an inner protective layer was bonded to the other surface, to obtain a polarizing plate.
In the same manner as in example 1, a polarizing plate having a curved surface was obtained. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
Example 3 and 4 >
A polarizing plate after being subjected to a curved surface processing was obtained in the same manner as in example 1 except that the polarizing plate having the structure shown in table 1 was used. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
Comparative example 1 >
A curved-surface-processed polarizing plate was obtained in the same manner as in example 2, except that the heating/humidifying treatment was not performed. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
Comparative example 2 and 3 >
A polarizing plate after being subjected to a curved surface treatment was obtained in the same manner as in comparative example 1 except that the polarizing plate having the structure shown in table 1 was used. The obtained polarizing plate was subjected to the same evaluation as in example 1. The results are shown in Table 1.
TABLE 1
As is clear from table 1, according to the embodiment of the present invention, the characteristics of the polarizing plate deteriorated by the curved surface processing can be recovered by the heating/humidifying treatment. More specifically, as is clear from comparison of example 2 with comparative example 1, example 3 with comparative example 2, and example 4 with comparative example 3, respectively, the transmittance and polarization degree of the monomer deteriorated by the curved surface processing are significantly recovered by the heating/humidifying treatment for the polarizing plate of the example. It is understood that the polarizing plate of the embodiment suppresses unevenness and discoloration in a crossed nicol state (corresponding to black display of an image display device).
Industrial applicability
The polarizing plate according to the embodiment of the present invention can be suitably used for an image display device having a curved surface (for example, a curved image display device).
Claims (4)
1. A polarizer, comprising:
polarizer and method of manufacturing the same
A protective layer disposed on at least one side of the polarizer,
the polarizer is subjected to surface processing, and after the surface processing, humidification treatment is carried out for more than 40 minutes in an environment of 40-65 ℃ and 85-95%RH,
the polarizer satisfies the following relationship:
Ts R －Ts 0 ＝ΔTs≤+1.5(％)
P R －P 0 ＝ΔP≥-1.5(％)
-2.0(nm)≤Re R －Re 0 ＝ΔRe≤+2.0(nm)
wherein Ts 0 Is the transmittance of the monomer before the curved surface processing, ts R The transmittance of the monomer after humidification treatment; p (P) 0 For degree of polarization before curved surface processing, P R The polarization degree after humidification treatment; re (Re) 0 Re is the in-plane retardation before the curved surface processing R Is the in-plane phase difference after the humidification treatment.
2. The polarizing plate according to claim 1, wherein,
defining 9 Re measured in each region of the region where the curved surface processing portion of the polarizing plate is divided into a grid 9 R The difference between the maximum value and the minimum value of (2) is 3.0nm or less.
3. A method for manufacturing a polarizing plate, wherein the polarizing plate is a polarizing plate having undergone a curved surface processing,
the manufacturing method comprises the following steps:
preparing a polarizing plate including a polarizer and a protective layer disposed on at least one side of the polarizer;
heating the polarizer together with a mold having a predetermined curved shape to perform curved surface processing; and
the polarizer subjected to the curved surface processing is subjected to humidification treatment for 40 minutes or longer in an environment of 40-65 ℃ and 85-95% RH.
4. The manufacturing method according to claim 3, wherein,
the heating temperature in the curved surface processing is more than 100 ℃.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020-185735 | 2020-11-06 | ||
| JP2020185735A JP2022075144A (en) | 2020-11-06 | 2020-11-06 | Polarizing plate with curved-surface processing and method for manufacturing the same |
| PCT/JP2021/040368 WO2022097631A1 (en) | 2020-11-06 | 2021-11-02 | Polarizing plate subjected to curved surface machining and method for manufacturing same |
Publications (1)
| Publication Number | Publication Date |
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| CN116635761A true CN116635761A (en) | 2023-08-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202180074832.6A Pending CN116635761A (en) | 2020-11-06 | 2021-11-02 | Polarizing plate after curved surface processing and method for manufacturing the same |
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| Country | Link |
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| JP (1) | JP2022075144A (en) |
| KR (1) | KR20230095933A (en) |
| CN (1) | CN116635761A (en) |
| TW (1) | TW202225747A (en) |
| WO (1) | WO2022097631A1 (en) |
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| WO2024202820A1 (en) * | 2023-03-28 | 2024-10-03 | 富士フイルム株式会社 | Light-absorbing anisotropic film, laminate, compound lens, and virtual reality display device |
| WO2024204501A1 (en) * | 2023-03-29 | 2024-10-03 | 富士フイルム株式会社 | Optical laminate, optical lens, and virtual reality display device |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05119216A (en) * | 1991-10-28 | 1993-05-18 | Mitsubishi Gas Chem Co Inc | Production of polarizing plate |
| JP3525543B2 (en) * | 1994-04-08 | 2004-05-10 | 住友化学工業株式会社 | Manufacturing method of polarizing plate |
| JP3211590B2 (en) | 1994-11-14 | 2001-09-25 | 住友化学工業株式会社 | Polarizer |
| JP2002258042A (en) * | 2001-03-02 | 2002-09-11 | Nitto Denko Corp | Polarizing plate and liquid crystal display device using the same |
| JP2004093993A (en) * | 2002-08-30 | 2004-03-25 | Nitto Denko Corp | Polarizer, optical film using the same, and liquid crystal display using the same as well as electroluminescence display |
| JP2006023573A (en) * | 2004-07-08 | 2006-01-26 | Nitto Denko Corp | Manufacturing method of polarizing plate, polarizing plate, and image display apparatus using polarizing plate |
| JP5633228B2 (en) * | 2009-09-17 | 2014-12-03 | 住友ベークライト株式会社 | Polarizing plate, polarizing lens and anti-glare product |
| JP2014142440A (en) * | 2013-01-23 | 2014-08-07 | Hoya Lense Manufacturing Philippine Inc | Method of manufacturing polarizing lens |
| JP7551279B2 (en) * | 2018-04-25 | 2024-09-17 | 住友化学株式会社 | Polarizing plate |
| EP3809170B1 (en) * | 2018-05-31 | 2023-11-22 | Hoya Lens Thailand Ltd. | Method for molding polarizing film, and method for manufacturing polarizing lens |
| JP7397605B2 (en) * | 2019-09-12 | 2023-12-13 | 住友化学株式会社 | Manufacturing method of polarizing plate |
| JP7461758B2 (en) * | 2020-02-26 | 2024-04-04 | 日東電工株式会社 | Method for restoring optical properties of polarizing plates deteriorated in high temperature environments |
-
2020
- 2020-11-06 JP JP2020185735A patent/JP2022075144A/en active Pending
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2021
- 2021-11-02 WO PCT/JP2021/040368 patent/WO2022097631A1/en active Application Filing
- 2021-11-02 KR KR1020237011359A patent/KR20230095933A/en active Search and Examination
- 2021-11-02 CN CN202180074832.6A patent/CN116635761A/en active Pending
- 2021-11-04 TW TW110141150A patent/TW202225747A/en unknown
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| WO2022097631A1 (en) | 2022-05-12 |
| KR20230095933A (en) | 2023-06-29 |
| TW202225747A (en) | 2022-07-01 |
| JP2022075144A (en) | 2022-05-18 |
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