Polarizing plate for OLED display screen

Abstract

The invention discloses a polarizer for an OLED display screen in the technical field of polarizers, and the polarizer comprises an upper protective film, a PVA polarizer, a lower protective film, a 1 / 4 lambda wave plate, a pressure-sensitive adhesive layer and a release film which are stacked in sequence, and the overall thickness is 60-70 [mu] m; pVA polarizers are formed by swelling, dyeing, bridging, extending and other processes of an NT system PVA original film, the thickness is controlled within 13 microns, and the thin structural design is achieved by matching with a protective film with the upper and lower thickness not larger than 20 microns; the 1 / 4 lambda wave plate is made of a liquid crystal compensation film or other high-phase-stability film material, and an angle of 45 degrees is formed between the optical axis direction of the 1 / 4 lambda wave plate and the PVA extension direction; the pressure-sensitive adhesive is a UV cured transparent adhesive, and is high in light transmittance and excellent in adhesion performance after being cured; the manufacturing method comprises the steps of PVA film treatment, functional film attachment, adhesive layer coating, UV curing and the like. The polarizer is clear in structural layer, reasonable in thickness control and suitable for integrated application of the curved-surface OLED display module.

Description

Technical Field

[0001] The invention relates to a polarizing plate for an OLED display screen, and belongs to the technical field of polarizers. Background Art

[0002] OLED display technology is gradually replacing traditional LCD technology due to its self-luminous properties, lightness, and flexibility. However, OLED panels are prone to reflected light interference under ambient light, which seriously affects the display contrast. The traditional solution is to attach a polarizing plate with a 1 / 4λ wave plate to the surface of the OLED panel to suppress reflection by converting reflected light into circularly polarized light. The existing OLED polarizing plates have the following major technical bottlenecks: the thickness of conventional PVA polarizers is too large, making it difficult for the overall polarizing plate to meet the needs of curved displays; the stacked structure of the protective film and the compensation film causes thickness accumulation, affecting the bending performance; a single 1 / 4λ wave plate is difficult to achieve full visible spectrum compensation, affecting the "one-piece black" display effect; the traditional water-based glue bonding process has poor adaptability to new hydrophobic materials; in addition, there is still room for optimization in the thickness matching of the functional layers of the polarizing plate, the coordination of optical performance, and the reliability of curved surface bonding. There is an urgent need to develop a new OLED polarizing plate structure that combines ultra-thin characteristics, excellent optical performance, and curved surface adaptability. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology and realize the thin structural design of the polarizer while ensuring high polarization degree and high transmittance, so as to adapt to the lamination application of OLED display screens, especially curved screens.

[0004] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions: In a first aspect, a polarizing plate for an OLED display is provided, comprising: A layer of stretched PVA polarizer, which is formed by swelling, dyeing, bridging, stretching, washing, fixing, and drying an NT-based PVA original film, wherein the thickness of the PVA polarizer is less than or equal to 13 μm and the transmittance is greater than 45%; Upper and lower protective films attached to the upper and lower sides of the PVA polarizer, wherein at least one layer of the protective film has a thickness of less than or equal to 20 μm and is made of at least one material selected from PMMA, PET, TAC, COP or SANUQI; A 1 / 4 λ wave plate attached to the outer side of the lower protective film, wherein the 1 / 4 λ wave plate is selected from a liquid crystal compensation film, an a-PAO compensation film, a COP compensation film, or a PC compensation film, and the thickness of the 1 / 4 λ wave plate is 2 to 10 μm; A UV-curable pressure-sensitive adhesive layer coated on the surface of the 1 / 4λ wave plate and a release film covering the surface of the pressure-sensitive adhesive layer; The overall thickness of the polarizer is 60-70 μm, and it has bending properties to meet the requirements of the curved OLED display.

[0005] Furthermore, the PVA polarizer is formed by an NT-based PVA film, boric acid is added to the PVA film during the stretching process, and the stretching ratio is 5 to 6 times.

[0006] Furthermore, the thickness of the upper protective film and the lower protective film of the PVA polarizer is no more than 20 μm, and the protective films are made of at least one material selected from PMMA, PET, TAC, COP or SANUQI.

[0007] Furthermore, the 1 / 4λ wave plate is a liquid crystal compensation film with a thickness of 2-10 μm, and the optical axis direction is set at an angle of 45° to the extension direction of the PVA polarizer.

[0008] Furthermore, a 1 / 2λ wave plate is provided between the 1 / 4λ wave plate and the lower protective film. The 1 / 2λ wave plate and the 1 / 4λ wave plate are made of the same material or a compatible polymer material. The thickness of the 1 / 2λ wave plate is 3-20 μm.

[0009] Furthermore, the pressure-sensitive adhesive layer is a UV-curable colloid, which is formed by mixing terminal hydrocarbon polybutadiene prepolymer, 3-isocyanate methylene-3,5,5-trimethylcyclohexyl isocyanate, ethyl acrylate, photoinitiator and nano-fumed silica.

[0010] Furthermore, the cured thickness of the pressure-sensitive adhesive layer is 5-25 μm, the colloid is colorless and transparent, and forms a cross-linked dense layer after UV irradiation.

[0011] Furthermore, the PVA polarizer is bonded to the protective film using a UV-curing colloid or a water-based adhesive bonding method, wherein the UV-curing colloid is used for bonding with the hydrophobic protective film material.

[0012] Furthermore, the polarizing plate has a total thickness of 60-70 μm and includes a PVA polarizer, two layers of protective films, a 1 / 4 λ wave plate, a pressure-sensitive adhesive layer and a release film.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a combined structure of ultra-thin PVA polarizers and thin protective films, combined with a 1 / 4λ wave plate of a specific thickness and a UV-curable adhesive layer, to achieve overall thickness control within the range of 60-70μm, with an ultra-thin structure, excellent optical performance and adaptability to curved surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Shown is a PVA extension flow chart provided by the present invention; Figure 2 Shown is a diagram showing the main structure of the polarizer provided by the present invention; Figure 3 The figure shows the structure and working principle of the polarizer for OLED provided by the present invention; Figure 4 The figure shows the thinned structure of the OLED polarizer provided by the present invention; Figure 5 The figure shows the change of polarization degree of the polarizing plate provided by the present invention along with transmittance; Figure 6 Shown is a comparison chart of reflectivity of different materials provided by the present invention; Figure 7 Shown is a comparison chart of the reflectivity Rt and transmittance Tt of different compensation materials provided by the present invention; Figure 8 Shown is a schematic diagram of the chemical structure of the UV prepolymer provided by the present invention; Figure 9 The figure shows the bonding diagram of UV glue and water glue provided by the present invention; Figure 10 Shown is the overall process flow chart provided by the present invention. DETAILED DESCRIPTION

[0015] The present invention will be described in further detail below with reference to specific embodiments and the accompanying drawings. Unless otherwise specified, the experimental methods described in the present invention are all conventional methods; and the materials used can be obtained from commercial sources.

[0016] like Figure 1 、 Figure 2 and Figure 10 As shown, this embodiment proposes a polarizing plate for an OLED display, including a stretched PVA polarizer, which is formed by swelling, dyeing, bridging, stretching, washing, fixing, and drying an NT-based PVA original film; an upper protective film and a lower protective film attached to the upper and lower sides of the PVA polarizer; a 1 / 4λ wave plate attached to the outer side of the lower protective film; a UV-curable pressure-sensitive adhesive layer coated on the surface of the 1 / 4λ wave plate, and a release film covering the surface of the pressure-sensitive adhesive layer.

[0017] PVA polarizers are formed through a multi-step stretching process. During the stretching process, the optical properties can be adjusted by controlling the boric acid concentration and stretching ratio. This process directionalizes the polymer chains to form stable polarization characteristics. The upper and lower protective films are made of high-transmittance materials, and the overall structure is thinned by reducing the film thickness while maintaining mechanical support. The 1 / 4λ wave plate uses a phase compensation material to convert linearly polarized light into circularly polarized light by adjusting the optical axis angle, effectively suppressing external light reflection. The UV-curable pressure-sensitive adhesive forms an adhesive layer through a light-induced cross-linking reaction, and its rapid curing characteristics meet the needs of automated production. The release film serves as a temporary protective layer to prevent contamination of the adhesive layer during transportation and storage.

[0018] Specifically, the PVA original film is directional stretched to form an optically anisotropic structure, and the upper and lower protective films are compounded with polarizers through adhesives to form a basic optical unit; the 1 / 4λ wave plate is laminated to the outside of the protective film at a precise angle to form a circular polarization conversion functional layer; the UV-curing adhesive layer undergoes a polymerization reaction under light of a specific wavelength to achieve rapid bonding and fixation; each functional layer forms an integrated structure through thickness control and interface optimization, achieving overall thickness control while ensuring optical performance.

[0019] PVA polarizer is formed by NT-based PVA film, to which boric acid is added during the stretching process, and the stretching ratio is 5~6 times; among them, NT-based PVA film refers to the original film prepared by high-polymerization degree polyvinyl alcohol material, and its molecular chain arrangement regularity is better than that of conventional PVA material, which can be achieved by combining chemical cross-linking with physical stretching, and improving the crystallinity by optimizing the polymerization process, so as to maintain a high optical uniformity after stretching; among them, boric acid addition refers to the introduction of boric acid solution as a cross-linking agent during the stretching stage of the PVA film, which can be achieved by dipping or spraying. Boric acid reacts with the hydroxyl groups on the PVA molecular chain to form a dynamic cross-linking network, which enhances the structural stability of the film during the stretching process; among them, the stretching ratio of 5~6 times means stretching the PVA original film to 5 to 6 times of its original length along a specific direction, which can be achieved through a multi-stage temperature-controlled roller stretching process. By adjusting the stretching rate and temperature in stages, the molecular chains are oriented and internal defects are reduced.

[0020] Specifically, when preparing PVA polarizers, the NT-based PVA original film is first treated with a boric acid solution, allowing the boric acid to fully penetrate into the interior of the film layer during the swelling stage, and then enters the stretching process; during the stretching process, the stretching temperature and tension are controlled in stages, so that the film material gradually reaches the target stretching ratio while maintaining moderate flexibility; the dynamic cross-linking effect of boric acid inhibits excessive slippage of the molecular chains in this process, while promoting orderly arrangement, ultimately forming a polarizer layer with uniform thickness and stable optical properties.

[0021] The present application further proposes that the thickness of the upper protective film and the lower protective film of the PVA polarizer are not more than 20 microns, and the protective films are made of at least one material selected from PMMA, PET, TAC, COP or SANUQI.

[0022] PMMA refers to polymethyl methacrylate, which can be achieved by a transparent film prepared by an extrusion molding process, and has high light transmittance and surface hardness; PET refers to polyethylene terephthalate, which can be achieved by a film prepared by a biaxial stretching process, and has excellent mechanical strength and heat resistance; TAC refers to cellulose triacetate, which can be achieved by a film prepared by a solution casting method, and has low birefringence and good optical uniformity; COP refers to cycloolefin polymer, which can be achieved by a film prepared by injection molding or extrusion molding, and has low moisture absorption and high weather resistance; SANUQI refers to a modified COP film, which can be prepared by copolymerization modification or surface treatment process, and has enhanced interfacial bonding and anti-bending properties; these materials can maintain the mechanical support effect of the protective film on the PVA polarizer under thinning conditions, while avoiding the decrease in scratch resistance due to reduced thickness.

[0023] Specifically, the upper and lower protective films achieve a thin overall structure by controlling the thickness to no more than 20 microns. At the same time, a material combination is selected from PMMA, PET, TAC, COP or SANUQI, so that the protective film can take into account mechanical strength while meeting the optical performance requirements; for example, when PMMA is used as the upper protective film, its high light transmittance can reduce light loss; when COP is used as the lower protective film, its low hygroscopicity can improve environmental stability; the interlayer bonding of the protective film and PVA polarizers is achieved by optimizing the interface treatment process, such as plasma treatment on the COP surface to enhance the bonding strength.

[0024] The present application further proposes a polarizing plate for an OLED display screen, wherein the 1 / 4λ wave plate is a liquid crystal compensation film with a thickness of 2 to 10 μm, and the optical axis direction is set at a 45° angle to the extension direction of the PVA polarizer.

[0025] like Figure 3 and Figure 4 As shown, the liquid crystal compensation film refers to an optical compensation film formed by the directional arrangement of liquid crystal molecules. It can be prepared by coating a liquid crystal material and then undergoing a directional solidification process. The phase difference compensation of a specific wavelength is achieved by adjusting the arrangement direction of the liquid crystal molecules. Its function is to optimize the circularly polarized light conversion efficiency and reduce the interference of external light reflection. The optical axis direction is set at a 45° angle, which means that the optical axis of the liquid crystal compensation film forms a specific angle with the extension direction of the PVA polarizer. This can be achieved by rotating and adjusting the angle when the film materials are bonded. This angle setting ensures that linearly polarized light is converted into circularly polarized light after passing through the compensation film, thereby eliminating the influence of external reflected light on the display contrast.

[0026] The liquid crystal compensation film is attached to the outside of the lower protective film, and its optical axis forms a 45° angle with the extension direction of the PVA polarizer, so that the phase difference of linearly polarized light after passing through the compensation film is one-quarter wavelength, forming circularly polarized light; after the external ambient light is incident on the OLED metal electrode and reflected, it cannot penetrate when passing through the compensation film and polarizer in the opposite direction, thereby significantly reducing the intensity of the reflected light; the thickness of the liquid crystal compensation film is controlled in the range of 2~10μm, which ensures the phase compensation effect while avoiding increasing the overall thickness, thereby meeting the demand for thin polarizers.

[0027] The present application further proposes to set a half-wave plate between the quarter-wave plate and the lower protective film. The half-wave plate and the quarter-wave plate are made of the same material or a compatible polymer material. The thickness of the half-wave plate is 3 to 20 microns.

[0028] like Figure 6 and Figure 7 As shown, a half-wavelength wave plate refers to an optical compensation element that can produce a half-wavelength phase delay to the incident light. Specifically, it can be achieved by using a liquid crystal compensation film, an a-PAO compensation film or a COP compensation film. Its phase delay effect can adjust the polarization direction of linearly polarized light; a compatible polymer material refers to a polymer substance with similar thermal expansion coefficient and adhesion properties to the quarter-wavelength wave plate material, such as polycarbonate or cycloolefin polymer using the same substrate to ensure the stability of the interlayer bonding; the selection of the thickness range of 3 to 20 microns is based on the balance between optical performance and mechanical strength. Too thin may lead to insufficient phase compensation, while too thick will affect the overall thinning requirements.

[0029] After external light passes through polarizers to form linearly polarized light, it is phase modulated by a half-wavelength wave plate and a quarter-wavelength wave plate in sequence; the half-wavelength wave plate first rotates the vibration direction of the linearly polarized light by a specific angle, and the quarter-wavelength wave plate further converts it into circularly polarized light; this dual compensation structure can expand the effective compensation band range, especially achieving more precise phase matching at both ends of the visible spectrum, thereby significantly reducing the intensity of reflected light; in terms of material selection, the use of the same substrate system can avoid interlayer delamination caused by thermal stress at the interface of different materials, while ensuring the integrity of the multilayer structure during the bending process.

[0030] The present application further proposes that the pressure-sensitive adhesive layer is a UV-curable colloid, which is a mixture of terminal hydrocarbon polybutadiene prepolymer, 3-isocyanate methylene-3,5,5-trimethylcyclohexyl isocyanate, ethyl acrylate, photoinitiator and nano-fumed silica.

[0031] Terminal hydrocarbon polybutadiene prepolymer refers to a prepolymer synthesized based on terminal hydroxyl polybutadiene, which can be achieved by reacting terminal hydroxyl polybutadiene with polyisocyanate to form a polyurethane acrylate structure. The flexible butadiene segment in its molecular chain can improve the anti-cracking performance of the colloid under bending conditions; 3-isocyanate methylene-3,5,5-trimethylcyclohexyl isocyanate refers to an alicyclic isocyanate crosslinker, which can be achieved by reacting with the hydroxyl groups in the prepolymer to form a crosslinked network. Its alicyclic structure can enhance the heat resistance and yellowing resistance of the adhesive layer; ethyl acrylate refers to an acrylate monomer containing an alkyl chain. Specifically, it can be achieved by using 2-ethylhexyl acrylate or isooctyl acrylate, and its long-chain alkyl group can reduce the colloidal modulus and improve the wettability of the hydrophobic protective film material; the photoinitiator refers to a compound that produces free radicals or cations under ultraviolet light irradiation, and can be specifically achieved by using benzoin or phosphine oxide initiators. By adjusting the initiator concentration, the curing rate and cross-linking density of the adhesive layer can be controlled; nano-gas-phase silica refers to nano-scale silica particles with surface treatment, and can be specifically achieved by dispersing hydrophobically modified gas-phase silica in a colloid. Its nanoparticles can improve the mechanical strength of the adhesive layer and inhibit curing shrinkage.

[0032] The terminal hydrocarbon polybutadiene prepolymer and the isocyanate crosslinker undergo free radical polymerization under the initiation of ultraviolet light to form a polyurethane acrylate matrix with a three-dimensional cross-linked network; the ethyl acrylate monomer adjusts the viscoelasticity and interfacial adhesion of the colloid through copolymerization; the nano-fumed silica enhances the peel strength of the adhesive layer through physical filling and surface interaction; the adhesive layer forms a dense structure after ultraviolet light irradiation, while maintaining efficient adhesion to the 1 / 4λ wave plate and the release film.

[0033] The present application further proposes that the cured thickness of the pressure-sensitive adhesive layer is 5 to 25 μm, the colloid is in a colorless and transparent state, and a cross-linked dense layer is formed after UV irradiation.

[0034] The cured thickness of 5~25μm refers to the final thickness range of the pressure-sensitive adhesive layer after UV curing, which can be controlled by adjusting the coating process parameters or the viscosity of the adhesive, such as using doctor blade coating or micro-gravure coating technology to achieve uniform coating; this thickness range can balance the bonding strength and material flexibility, and avoid the increase in the overall rigidity of the polarizing plate due to excessive thickness, which affects the curved surface bonding performance; the colorless and transparent state means that the colloid maintains optical transparency after curing, which can be achieved by selecting a prepolymer without chromogenic groups and a nanofiller dispersion process, such as using ethyl acrylate as the main chain monomer and adding nano-gas-phase silica to improve optical uniformity; the cross-linked dense layer refers to the three-dimensional network structure formed after the colloid is initiated by UV light, which can be achieved through the synergistic effect of the photoinitiator and the multifunctional monomer, such as using 3-isocyanate methylene-3,5,5-trimethylcyclohexyl isocyanate as a cross-linking agent to give the adhesive layer a dense cross-linked network.

[0035] During the polarizing plate manufacturing process, the prepared pressure-sensitive adhesive is applied to the surface of the 1 / 4λ wave plate, and the wet film thickness is controlled by precision coating equipment. Then, a release film is covered for initial leveling. During the UV curing stage, ultraviolet light of a specific wavelength penetrates the release film to trigger a polymerization reaction of the photosensitive components in the adhesive. By adjusting the light intensity and time, the adhesive layer forms a uniform cross-linked structure. The cured adhesive layer maintains transparency to avoid affecting the display effect, and improves moisture and heat resistance through a dense cross-linked network. At the same time, the thickness range of 5~25μm ensures that the adhesive layer can withstand bending stress without cracking or debonding when the curved surface is bonded.

[0036] The present application further proposes that the PVA polarizer laminating protective film adopts a UV curing colloid or a water-based adhesive laminating method, wherein the UV curing colloid is used for laminating with the hydrophobic protective film material.

[0037] Among them, Figure 8 and Figure 9 As shown, UV curing colloid refers to an adhesive that forms a cross-linked structure by initiating polymerization reaction through ultraviolet irradiation. Specifically, it can be achieved by a colloid made of a mixture of terminal hydrocarbon polybutadiene prepolymer, ethyl acrylate and photoinitiator. It has a fast curing speed and does not require high-temperature treatment, and is suitable for automated production lines; hydrophobic protective film material refers to a polymer material whose surface is not easily wetted by water. Specifically, it can be achieved by materials such as COP, PMMA or PET. Such materials lack hydrophilic groups, making it difficult for traditional water-based glue to effectively wet and penetrate, and UV glue is required to achieve reliable bonding; water-based glue bonding refers to an adhesive with water as the solvent that forms an adhesive layer by natural drying or heat drying after coating. Specifically, it can be achieved by polyvinyl alcohol or acrylic water-based glue, which is suitable for bonding hydrophilic protective film materials.

[0038] By adjusting the ratio of prepolymer and photoinitiator, UV curing colloid can quickly form a dense cross-linked structure under ultraviolet light, thereby firmly bonding the hydrophobic protective film to PVA polarizers; for hydrophobic membranes such as COP and PMMA, the water in traditional water-based adhesives is difficult to evaporate, which can easily lead to residual bubbles or debonding in the adhesive layer, while UV adhesive avoids the problem of solvent volatilization through the light curing mechanism and directly forms a uniform adhesive layer; water-based adhesive bonding is suitable for hydrophilic membranes such as TAC, and uses water molecules to form hydrogen bonds with the hydroxyl groups on the surface of the membrane to achieve bonding; the two bonding methods are differentiated according to the hydrophilic and hydrophobic properties of the protective film material to ensure the interface bonding strength and optical properties under different material combinations.

[0039] The present application further proposes that the total thickness of the polarizing plate is 60 to 70 microns, and includes a PVA polarizer, two layers of protective films, a 1 / 4 lambda wave plate, a pressure-sensitive adhesive layer, and a release film.

[0040] PVA polarizer refers to a polyvinyl alcohol layer formed by stretching treatment, which can be achieved by swelling, dyeing, bridging, stretching, washing, fixing and drying processes of NT series PVA original film. Its thickness is controlled by adjusting the stretching ratio and processing parameters. This layer is used to generate linearly polarized light and control the transmittance; wherein, the protective film refers to a polymer material layer attached to the upper and lower sides of the PVA polarizer, which can be made of at least one material selected from PMMA, PET, TAC, COP or SANUQI through extrusion or casting process. Its thickness is controlled by selecting thin materials. This layer is used to protect the PVA polarizer and reduce the overall Thickness; wherein, the 1 / 4λ wave plate refers to a compensation film layer with a phase delay function, which can be specifically achieved by a liquid crystal compensation film, an a-PAO compensation film, a COP compensation film or a PC compensation film through a coating or lamination process, and its thickness is controlled by selecting an ultra-thin material or completing precision processing. This layer is used to convert linearly polarized light into circularly polarized light to reduce external light reflection; wherein, the pressure-sensitive adhesive layer refers to an ultraviolet light-curable colloid with an adhesive function, which can be specifically formed by mixing a terminal hydrocarbon polybutadiene prepolymer, an isocyanate monomer, an acrylate monomer and a photoinitiator and then cross-linking them through UV irradiation. This layer is used to adhere the polarizing plate to the surface of the OLED display.

[0041] The polarizing plate is formed by laminating a PVA polarizer with upper and lower protective films, and sequentially placing a 1 / 4λ wave plate, a pressure-sensitive adhesive layer, and a release film on the outside of the lower protective film to form a multi-layer composite structure. The thickness of the PVA polarizer is controlled below 13 microns through a high-rate stretching process, the protective film is made of a thin material below 20 microns, and the 1 / 4λ wave plate uses a liquid crystal compensation film of 2 to 10 microns. The thickness of each layer is synergistically optimized to achieve an overall thickness of 60 to 70 microns. By reducing the thickness of each layer and selecting high-modulus materials, this structure improves bending performance while ensuring optical performance.

[0042] In some specific embodiments, the PVA polarizer can be formed by using an NT-based PVA film that is stretched with the assistance of boric acid, with the stretching ratio controlled at 5 to 6 times; the protective film can be a combination of 10-micron PMMA and 15-micron SANUQI; the 1 / 4 λ wave plate can be a 5-micron thick liquid crystal compensation film, the optical axis of which forms a 45° angle with the PVA stretching direction; the pressure-sensitive adhesive layer can be formed by a spin coating process to form a 10-micron thick colorless transparent adhesive layer.

[0043] The present application further proposes that the pressure-sensitive adhesive layer is a UV-curable colloid, which is a mixture of terminal hydrocarbon polybutadiene prepolymer, 3-isocyanate methylene-3,5,5-trimethylcyclohexyl isocyanate, ethyl acrylate, photoinitiator and nano-gas-phase silica. The cured thickness is 5~25μm, the colloid is colorless and transparent, and forms a cross-linked dense layer after UV irradiation.

[0044] A terminal hydrocarbon polybutadiene prepolymer refers to a polybutadiene polymer with terminal reactive groups. As the basic skeleton of the colloid, it can provide flexibility and initial adhesion. 3-Isocyanate methylene-3,5,5-trimethylcyclohexyl isocyanate refers to a multifunctional isocyanate compound. As a cross-linking agent, it reacts with the hydroxyl groups in the prepolymer to form a three-dimensional network structure, thereby enhancing the heat resistance and moisture resistance of the adhesive layer. Ethyl acrylate refers to a monomer containing an acrylate group, which is used to adjust the rheological properties of the colloid and the adhesion after curing. A photoinitiator refers to a compound that generates free radicals or cations under ultraviolet light, which is used to initiate the polymerization reaction of the prepolymer and monomer. Nano-fumed silica refers to surface-treated nano-scale silica particles, which are used to improve the mechanical strength and anti-settling properties of the colloid and prevent cracks or bubbles from occurring during the curing process.

[0045] The UV-curable colloid quickly forms a dense cross-linked network structure under UV light through the synergistic cross-linking effect of terminal hydrocarbon polybutadiene prepolymer and 3-isocyanate methylene-3,5,5-trimethylcyclohexyl isocyanate; the introduction of ethyl acrylate can adjust the interfacial compatibility of the colloid with different substrates, ensuring that no bubbles remain during the bonding process; the selection and concentration control of the photoinitiator can achieve a balance between curing speed and depth, avoiding bonding failure caused by incomplete curing; nano-gas-phase silica is evenly dispersed in the colloid, enhancing the shear resistance and durability of the adhesive layer through physical filling and surface interaction, while maintaining transparency after curing.

[0046] The above description is only a preferred embodiment of the present invention, but is not intended to limit the embodiments of the present invention. It should be understood by those skilled in the art that any modifications, equivalent substitutions and improvements based on the present invention, without departing from the creative concept of the present invention, fall within the scope of protection claimed in the present invention.

Claims

1. A polarizing plate for an OLED display, characterized in that: include: A layer of stretched PVA polarizer, which is formed by swelling, dyeing, bridging, stretching, washing, fixing, and drying an NT-based PVA original film, wherein the thickness of the PVA polarizer is less than or equal to 13 μm and the transmittance is greater than 45%; Upper and lower protective films attached to the upper and lower sides of the PVA polarizer, wherein at least one layer of the protective film has a thickness of less than or equal to 20 μm and is made of at least one material selected from PMMA, PET, TAC, COP or SANUQI; A 1 / 4 λ wave plate attached to the outer side of the lower protective film, wherein the 1 / 4 λ wave plate is selected from a liquid crystal compensation film, an a-PAO compensation film, a COP compensation film, or a PC compensation film, and the thickness of the 1 / 4 λ wave plate is 2 to 10 μm; A UV-curable pressure-sensitive adhesive layer coated on the surface of the 1 / 4λ wave plate and a release film covering the surface of the pressure-sensitive adhesive layer; The overall thickness of the polarizer is 60-70 μm, and it has bending properties to meet the requirements of the curved OLED display.

2. The polarizing plate for an OLED display according to claim 1, wherein: The PVA polarizer is formed by an NT-based PVA film, to which boric acid is added during the stretching process, and the stretching ratio is 5 to 6 times.

3. The polarizing plate for an OLED display according to claim 1, wherein: The thickness of the upper protective film and the lower protective film of the PVA polarizer is no more than 20 μm, and the protective films are made of at least one material selected from PMMA, PET, TAC, COP or SANUQI.

4. The polarizing plate for an OLED display according to claim 1, wherein: The 1 / 4λ wave plate is a liquid crystal compensation film with a thickness of 2-10 μm, and the optical axis direction is set at an angle of 45° with the extension direction of the PVA polarizer.

5. The polarizing plate for an OLED display according to claim 1, wherein: A 1 / 2λ wave plate is provided between the 1 / 4λ wave plate and the lower protective film. The 1 / 2λ wave plate and the 1 / 4λ wave plate are made of the same material or a compatible polymer material. The thickness of the 1 / 2λ wave plate is 3-20 μm.

6. The polarizing plate for an OLED display according to claim 1, wherein: The pressure-sensitive adhesive layer is a UV-curable colloid, which is formed by mixing terminal hydrocarbon polybutadiene prepolymer, 3-isocyanate methylene-3,5,5-trimethylcyclohexyl isocyanate, ethyl acrylate, photoinitiator and nano-gas-phase silica.

7. The polarizing plate for an OLED display according to claim 1, wherein: The cured thickness of the pressure-sensitive adhesive layer is 5-25 μm, the colloid is colorless and transparent, and forms a cross-linked dense layer after UV irradiation.

8. The polarizing plate for an OLED display according to claim 1, wherein: The PVA polarizer is bonded to the protective film using a UV-curing colloid or a water-based adhesive, wherein the UV-curing colloid is used for bonding with the hydrophobic protective film material.

9. The polarizing plate for an OLED display according to claim 1, wherein: The polarizing plate has a total thickness of 60-70 μm and includes a PVA polarizer, two layers of protective film, a 1 / 4 λ wave plate, a pressure-sensitive adhesive layer and a release film.

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