Polarizer and display device

Abstract

The invention relates to a polaroid and a display device, the polaroid comprises a polarizing layer and a protective film arranged on one side of the polarizing layer, the protective film comprises a base material layer and a blocking layer, the blocking layer is located on the side, away from the polarizing layer, of the base material layer, and the material of the blocking layer comprises polyvinylidene chloride. According to the polaroid, the PVDC barrier layer is additionally arranged on the surface of the base material layer of the protective film, the PVDC barrier layer has good moisture resistance and gas resistance, the overall water vapor barrier performance of the protective film can be remarkably improved, and then the problems of light leakage and the like caused by moisture absorption of the polaroid can be effectively solved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a polarizer and a display device. Background Art

[0002] Liquid crystal displays are widely used due to their own advantages. Liquid crystal displays are composed of an upper polarizer, a lower polarizer, and a liquid crystal display panel located between the two. Polarizers are an important component of liquid crystal displays. When liquid crystal displays are assembled into a complete TV set, the protective film covering the surface of the lower polarizer of the liquid crystal display panel will be torn off, and the protective film of the upper polarizer will be retained to protect the polarizer and the liquid crystal display panel. After the TV set is assembled, labels such as the model, attributes, and QR code of the TV set will be pasted on the protective film of the upper polarizer, and then put into a protective bag and packed in a carton. Panel factories and complete machine factories are concentrated in East Asia, which means that TV sets must be transported by land, air, and sea for a long time, passing through areas with different temperature and humidity environments, and placed in warehouses with different temperatures and humidity for long-term storage. In recent years, complete machine factories have gradually set up factories in the Americas, and displays will also arrive in the Americas after a long period of sea transportation. The hot and humid environment of containers for more than a month has put a great test on polarizers. Since the protective film of the upper polarizer is made of polyethylene terephthalate (PET), although PET is a low moisture permeability material, in a high temperature and hot environment, coupled with the interference of labels and protective bags, it is easy to cause uneven moisture absorption of the upper polarizer, resulting in irregular light leakage (mura) in some areas. When the high temperature and hot storage time is prolonged, water vapor will condense and adhere to the surface of the PET protective film, directly pass through the PET protective film to reach the surface of the upper polarizer, forming a siphon effect, causing the upper polarizer to absorb water and cause serious light leakage (mura). These problems will generate a large number of terminal customer complaints, so it is urgent to improve the water vapor barrier capacity of the polarizer. Summary of the invention

[0003] The embodiments of the present application provide a polarizer and a display device, which can significantly improve the overall water vapor barrier performance of the protective film and improve problems such as light leakage caused by moisture absorption of the polarizer.

[0004] In order to achieve the above object, the present application provides a polarizer, which includes:

[0005] a polarizing layer; and

[0006] A protective film, disposed on at least one side of the polarizing layer;

[0007] Wherein, the protective film comprises a substrate layer and a barrier layer, the barrier layer is located on a side of the substrate layer away from the polarizing layer, and the material of the barrier layer comprises polyvinylidene chloride.

[0008] In some embodiments, the barrier layer is a polyvinylidene chloride latex coating or a polyvinylidene chloride resin film.

[0009] In some embodiments, the substrate layer includes a substrate including at least one of polypropylene, polyethylene, polycarbonate, polyethylene terephthalate, and polyethylene naphthalate.

[0010] In some embodiments, the substrate comprises biaxially stretched polypropylene.

[0011] In some embodiments, the substrate layer further comprises nanofillers.

[0012] In some embodiments, the mass of the nanofiller accounts for 0.01% to 1% of the total mass of the substrate layer material.

[0013] In some embodiments, the nanofiller comprises nanographene.

[0014] In some embodiments, the thickness of the substrate layer ranges from 30 μm to 100 μm, and the thickness of the barrier layer ranges from 0.5 μm to 20 μm.

[0015] In some embodiments, the optical transmittance of the protective film is 85% to 100%.

[0016] The present application also provides a display device, the display device comprising:

[0017] Display panel;

[0018] A first polarizer, arranged on the light-emitting side of the display panel;

[0019] A second polarizer is arranged on a side of the display panel away from the first polarizer;

[0020] Wherein, the first polarizer is the polarizer as described above.

[0021] The present application provides a polarizer and a display device. The polarizer of the present application includes a polarizing layer and a protective film located on one side of the polarizing layer. The protective film includes a substrate layer and a barrier layer. The material of the barrier layer includes polyvinylidene chloride (PVDC). The present application adds a PVDC film layer on the surface of the substrate layer of the protective film. The PVDC film layer has good moisture barrier and gas barrier properties, which can significantly improve the overall water vapor barrier property of the protective film, thereby effectively improving the light leakage problem caused by moisture absorption of the polarizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a display device provided by the prior art;

[0023] Figure 2It is a schematic diagram of the mechanism of water vapor passing through the first protective film made of PET;

[0024] Figure 3 is a schematic structural diagram of a polarizer provided in an embodiment of the present application;

[0025] Figure 4 is a schematic diagram of a protective film structure of a polarizer provided in an embodiment of the present application;

[0026] Figure 5 is a schematic diagram of the protective film structure of another polarizer provided in an embodiment of the present application;

[0027] Figure 6 It is a structural schematic diagram of a display device provided in an embodiment of the present application.

[0028] Description of reference numerals:

[0029] 100, polarizer; 110, polarizing layer; 120, protective film; 121, substrate layer; 122, barrier layer; 1211, substrate; 1212, nanofiller; 123, adhesive layer; 200, display panel; 310, first polarizer; 311, first polarizing layer; 312, first protective film; 320, second polarizer; 321, second polarizing layer; 322, second protective film; 400, backlight module. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0031] See also Figure 1 , Figure 1It is a structural schematic diagram of a display device provided by the prior art. In the prior art, the display device includes a display panel 200 and a first polarizer 310 and a second polarizer 320 located on opposite sides of the display panel 200. The first polarizer 310 is located on the light-emitting side of the display panel 200, and includes a first polarizing layer 311 and a first protective film 312 located on the side of the first polarizing layer 311 away from the display panel 200. The second polarizer 320 includes a second polarizing layer 321 and a second protective film 322 located on the side of the second polarizing layer 321 away from the display panel 200. Both the first protective film 312 and the second protective film 322 are made of PET material. The second protective film 322 is usually torn off and assembled with other structures of the display device, and the first protective film 312 is still retained to protect the display device. When the display device is stored in a high temperature environment for a long time, the first protective film 312 made of PET material on its surface will have a siphon effect, causing water vapor to enter the interior of the first polarizer 310. For details, please refer to Figure 2 In a high climatic and hot environment, the water vapor concentration in the environment is high, and the water vapor diffuses from the high concentration side to the low concentration side. The water vapor molecules are first adsorbed on the surface of the first protective film 312 (referring to the side of the first protective film 312 away from the first polarizing layer 311), and then diffuse in the first protective film 312, and enter the side of the first protective film 312 close to the first polarizing layer 311 after desorption, causing the first polarizing layer 311 to absorb water, resulting in serious light leakage (mura) of the first polarizer 310.

[0032] To solve the above problems, please refer to Figure 3 The present application provides a polarizer 100, which includes a polarizing layer 110 and a protective film 120 arranged on at least one side of the polarizing layer 110, wherein the protective film 120 includes a substrate layer 121 and a barrier layer 122, the barrier layer 122 is located on a side of the substrate layer 121 away from the polarizing layer 110, and the material of the barrier layer 122 includes polyvinylidene chloride (PVDC).

[0033] Polyvinylidene chloride (PVDC) is a copolymer with vinylidene chloride as the main component, with a linear polymer chain structure connected head to tail. Due to its strong intermolecular cohesion and high crystallinity, the chlorine atoms in the PVDC molecules are hydrophobic and will not form hydrogen bonds. It is difficult for oxygen molecules and water molecules to move in the PVDC molecules, which makes it have excellent moisture and oxygen barriers, and its oxygen barrier is not affected by the humidity of the surrounding environment. Conventional protective film materials, such as acrylic emulsions, will have a sharp drop in gas barrier properties as their moisture absorption performance increases, and nylon films will have a decrease in moisture barrier properties as their gas barrier properties increase. Therefore, PVDC has excellent ability to block water vapor and oxygen under any temperature or humidity conditions, and has better comprehensive performance in terms of barrier properties.

[0034] The present application adds a barrier layer 122 on the surface of the substrate layer 121 of the protective film 120. The barrier layer 122 is made of PVDC material and utilizes the high moisture barrier properties of the PVDC material to further improve the overall water vapor barrier properties of the protective film 120, thereby effectively improving problems such as light leakage caused by moisture absorption of the polarizer 100. At the same time, the PVDC material also has high gas barrier properties, which can further improve the oxygen barrier performance of the protective film 120.

[0035] In some embodiments, the barrier layer 122 may be a polyvinylidene chloride resin film, that is, the barrier layer 122 is a film formed by extruding a polyvinylidene chloride resin material, and the protective film 120 is formed by attaching the polyvinylidene chloride resin film to the surface of the substrate layer 121. The polyvinylidene chloride resin film may be formed by PVDC resin alone, or by blending with other additives. Specifically, a film may be formed by using a film blowing machine and extrusion production and processing. In this embodiment, the polyvinylidene chloride resin film may be, for example, a PVDC epoxy resin film, but is not limited thereto.

[0036] In some embodiments, the barrier layer 122 is a polyvinylidene chloride latex coating, that is, the raw material of the barrier layer 122 is in the form of an emulsion, and a layer of polyvinylidene chloride latex coating is formed on the surface of the substrate layer 121 through a coating process, and the substrate layer 121 and the polyvinylidene chloride latex coating together constitute the protective film 120. Compared with the above-mentioned extruded polyvinylidene chloride resin film, the polyvinylidene chloride latex coating of this embodiment adopts latex coating, and there are only coating spreading and heating and drying processes, and there is no additional additive in the final film formation. Therefore, although the coating is only 2μm-3μm thick, its barrier performance against moisture and oxygen is equivalent to the barrier performance of a 25μm blown film. Using the polyvinylidene chloride latex coating as the barrier layer 122 can further reduce the thickness of the barrier layer 122, thereby reducing the impact on the overall thickness of the display device.

[0037] In some embodiments, see Figure 4 The substrate layer 121 includes a substrate 1211, and the material of the substrate 1211 includes at least one of polypropylene (PP), polyethylene (PE), polycarbonate (PC), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). These materials can be used as the main components of the protective film 120 to protect the polarizer 100. The barrier layer 122 is formed on the surface of the substrate layer 121 formed by these materials, so that the protective film 120 can have both the protection of the polarizer 100 and the function of blocking water vapor. In this way, while protecting the polarizer 100, the intrusion of water vapor is further blocked to avoid the problem of light leakage caused by moisture absorption of the polarizer 100.

[0038] In some embodiments, the substrate 1211 includes biaxially stretched polypropylene (BOPP). Biaxially stretched polypropylene (BOPP) is made by coextruding polypropylene particles into a sheet and then stretching it in both the longitudinal and transverse directions. Due to the orientation of the stretched molecules, the film has good physical stability, mechanical strength, and air tightness, high transparency and gloss, toughness and wear resistance, and good printability. In the present application, the biaxially stretched polypropylene film is compounded with a polyvinylidene chloride latex coating, so that the protective film 120 has high transparency, good air tightness, good printability, and excellent moisture barrier properties.

[0039] In this embodiment, biaxially stretched polypropylene (BOPP) has better printing performance than substrates 1211 such as polypropylene (PP), polyethylene (PE), polycarbonate (PC), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). When a coating is applied on the surface of the biaxially stretched polypropylene (BOPP) substrate, the surface coating performance is better and the adhesion is good, so that the coating is not easy to fall off.

[0040] In some embodiments, see Figure 5 , the substrate layer 121 further includes a nanofiller 1212. By adding the nanofiller 1212 to the substrate 1211, the water vapor permeability of the substrate layer 121 can be reduced, and the water vapor barrier performance of the protective film 120 can be further improved. Since the nanofiller 1212 is evenly dispersed in the substrate layer 121, the nanofiller 1212 can fill the gaps between the molecules of the substrate 1211, reduce the permeation channels of water vapor molecules, and further reduce the water vapor permeability of the substrate layer 121, that is, improve the moisture barrier performance of the substrate layer 121. The nanofiller 1212 can be an organic filler or an inorganic filler, which is not limited here.

[0041] In some embodiments, the nanofiller 1212 may be nanographene. Nanographene has a very high transparency, almost completely transparent, and adding it to the substrate layer 121 will not affect the transmittance of the protective film 120. Nanographene has a special flaky structure and excellent mechanical properties, which is beneficial to improving the barrier properties of polymer materials. In the present application, adding nanographene to the substrate layer 121 can significantly improve the moisture barrier properties of the substrate layer 121. Moreover, adding a small amount of nanographene to the substrate layer 121 can greatly reduce the water vapor permeability of the substrate layer 121.

[0042] In some embodiments, the mass of the nanofiller 1212 accounts for 0.01% to 1% of the total mass of the material of the substrate layer 121. For example, adding 0.01% to 1% of nanographene to the biaxially oriented polypropylene (BOPP) substrate 1211 can significantly improve the moisture barrier performance of the substrate layer 121. When the content of the nanofiller 1212 in the substrate layer 121 is lower than the above range, the barrier layer 122 cannot block water vapor because the content of the nanofiller 1212 is too low; when the content of the nanofiller 1212 in the substrate layer 121 is higher than the above range, the mechanical properties of the substrate layer 121 will be changed, and the cost will be increased.

[0043] In some embodiments, the thickness of the substrate layer 121 ranges from 30 μm to 100 μm. Further, considering economic efficiency, the thickness of the substrate layer 121 ranges from 30 μm to 50 μm. The thickness of the barrier layer 122 ranges from 0.5 μm to 20 μm. Further, considering economic efficiency, the thickness of the barrier layer 122 ranges from 2 μm to 5 μm. When the thickness of the substrate layer 121 and the barrier layer 122 is within the above range, it can ensure that the protective film 120 has better protection performance and better water vapor barrier performance, and will not affect the optical, mechanical and other properties of the protective film 120.

[0044] In some embodiments, the optical transmittance of the protective film 120 is 85% to 100%. Since the nanofiller 1212 added to the substrate layer 121 of the present application is transparent nanographene, and the thickness of the polyvinylidene chloride latex coating formed by the coating process of the barrier layer 122 is relatively thin, the optical transmittance of the protective film 120 can still reach more than 85%, while improving the moisture barrier performance of the protective film 120, it still maintains a relatively high transmittance.

[0045] In some embodiments, see Figure 3The polarizer 100 further includes an adhesive layer 123, and the adhesive layer 123 is located between the barrier layer 122 and the polarizing layer 110. The material of the adhesive layer 123 can be a pressure-sensitive adhesive, but is not limited thereto.

[0046] In some embodiments, the polarizer 100 may further include a compensation layer or other conventional film layers in the art located on one side of the polarizing layer 110. The material of the compensation layer may be triacetate film (TAC), phase difference film, etc., but is not limited thereto.

[0047] In the present application, the material of the polarizing layer 110 may be polyvinyl alcohol (PVA), but is not limited thereto.

[0048] The water vapor permeability of the protective film 120 of the present application is further described below through specific experiments.

[0049] Examples 1 to 5 of the present application respectively used protective films with different PVDC barrier layer thicknesses and different nano-graphene contents to test water vapor permeability. The comparative example used an existing PET film as the protective film. The test results are shown in Table 1.

[0050] The substrates of Examples 1 to 5 are the same, all of which are BOPP, and the thickness of the substrate layer is 38 μm, and the thickness of the PSA adhesive of Examples 1 to 5 is 15 μm. The substrate of the comparative example is PET, with a thickness of 38 μm, and the thickness of the PSA adhesive is 15 μm.

[0051] Table 1

[0052]

[0053] The water vapor transmission rate, water vapor transmission amount and water vapor transmission coefficient are measured in accordance with GB / T1037-1988 "Test method for water vapor transmission of plastic film and sheet---cup method" (corresponding to the American Testing and Association Standard ASTM E96-1980). Test conditions: temperature: 38+0.6℃, relative humidity 90+2%.

[0054] It can be seen from the results in Table 1 that the water vapor permeability of the protective films of Examples 1 to 5 of the present application is significantly lower than that of the comparative example, which proves that the addition of nanographene to the PVDC barrier layer 122 and the substrate 1211 can significantly improve the water vapor barrier performance of the protective film, while the water vapor permeability of the existing PET protective film is 3.3 to 400 times that of the protective film of the present application.

[0055] By comparing Examples 1 to 2 with Comparative Example 1, it can be seen that no nanographene is added in Examples 1, 2 and the Comparative Example, and PVDC barrier layers are used in Examples 1 and 2, and the thickness of the PVDC barrier layer in Example 2 is greater than the thickness of the PVDC barrier layer in Example 1, which proves that the PVDC barrier layer can effectively reduce the water vapor permeability of the protective film, and the thicker the PVDC barrier layer, the lower the water vapor permeability.

[0056] By comparing Example 2, Example 3 with Example 5, it can be seen that the thickness of the PVDC barrier layer of Example 2, Example 3 and Example 5 is the same, but the content of nanographene in the substrate of Example 2, Example 3 and Example 5 increases successively, and the water vapor permeability of Example 2, Example 3 and Example 5 decreases successively, which proves that adding nanographene to the substrate can effectively reduce the water vapor permeability of the protective film, and the more nanographene content, the lower the water vapor permeability.

[0057] By comparing Examples 3 to 5 with Comparative Example 1, it can be seen that nano-graphene is added to the substrates of Examples 3 to 5, while nano-graphene is not added to Comparative Example 1. The water vapor permeability of Examples 3 to 5 is only 2% to 0.25% of that of Comparative Example 1. The water vapor permeability of the protective film using the PVDC barrier layer and the nano-graphene added in the present application is significantly lower than that of the PET protective film in the comparative example.

[0058] The present application also provides a display device, see Figure 6 The display device includes a display panel 200, a first polarizer 310, and a second polarizer 320. The first polarizer 310 is arranged on the light emitting side of the display panel 200, and the second polarizer 320 is arranged on a side of the display panel 200 away from the first polarizer 310; wherein the first polarizer 310 is the polarizer 100 as described above.

[0059] Specifically, the first polarizer 310 includes a polarizing layer 110 and a protective film 120 disposed on a side of the polarizing layer 110 away from the display panel 200, wherein the protective film 120 includes a substrate layer 121, a barrier layer 122 and an adhesive layer 123, the barrier layer 122 is located on a side of the substrate layer 121 away from the polarizing layer 110, and the material of the barrier layer 122 includes polyvinylidene chloride (PVDC).

[0060] In some embodiments, the display panel 200 may be a liquid crystal display panel 200 , but is not limited thereto.

[0061] In some embodiments, the display device further includes a backlight module 400 , which is disposed on a side of the second polarizer 320 away from the display panel 200 . The structure of the backlight module 400 may refer to the prior art and will not be described in detail herein.

[0062] In the present application, the display device may be a display product such as a television, a computer, a tablet, etc., but is not limited thereto.

[0063] The present application provides a polarizer and a display device. The polarizer of the present application includes a polarizing layer and a protective film located on one side of the polarizing layer. The protective film includes a substrate layer and a barrier layer. The material of the barrier layer includes polyvinylidene chloride (PVDC). The present application adds a PVDC film layer on the surface of the substrate layer of the protective film. The PVDC film layer has good moisture barrier and gas barrier properties, which can improve the overall water vapor barrier property of the protective film, thereby effectively improving the light leakage problem caused by moisture absorption of the polarizer.

[0064] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0065] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0066] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0067] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A polarizer, characterized in that: include: Polarizing layer; as well as A protective film, disposed on at least one side of the polarizing layer; Wherein, the protective film comprises a substrate layer and a barrier layer, the barrier layer is located on a side of the substrate layer away from the polarizing layer, and the material of the barrier layer comprises polyvinylidene chloride.

2. The polarizer according to claim 1, characterized in that: The barrier layer is a polyvinylidene chloride latex coating or a polyvinylidene chloride resin film.

3. The polarizer according to claim 1, characterized in that: The substrate layer includes a substrate, and the substrate includes at least one of polypropylene, polyethylene, polycarbonate, polyethylene terephthalate, and polyethylene naphthalate.

4. The polarizer according to claim 3, characterized in that: The substrate comprises biaxially stretched polypropylene.

5. The polarizer according to claim 1, characterized in that: The substrate layer also includes nanofillers.

6. The polarizer according to claim 5, characterized in that: The mass of the nanofiller accounts for 0.01% to 1% of the total mass of the material of the substrate layer.

7. The polarizer according to claim 5, characterized in that: The nanofiller includes nanographene.

8. The polarizer according to any one of claims 1 to 7, characterized in that: The thickness of the substrate layer ranges from 30 μm to 100 μm, and the thickness of the barrier layer ranges from 0.5 μm to 20 μm.

9. The polarizer according to any one of claims 1 to 7, characterized in that: The optical transmittance of the protective film is 85% to 100%.

10. A display device, characterized in that: include: Display panel; A first polarizer, arranged on the light-emitting side of the display panel; A second polarizer is arranged on a side of the display panel away from the first polarizer; Wherein, the first polarizer is the polarizer as claimed in any one of claims 1 to 9.

Images