KR20180030564A - POLARIZING PLATE, IMAGE DISPLAY APPARATUS AND PROCESS FOR PRODUCING POLARIZER - Google Patents

Abstract

The polarizing plate 1A is provided with a polarizer 2 and protective films 3 and 3 laminated on both surfaces thereof. Each of the protective films 3 and 3 is formed in a predetermined shape and each of the protective films 3 and 3 is laminated on the entire surface of one side of the polarizer 2 and at least a part of the ends 2a of the polarizer 2 Is positioned inside the end portion (3a) of at least one of the protective films (3).

Description

POLARIZING PLATE, IMAGE DISPLAY APPARATUS AND PROCESS FOR PRODUCING POLARIZER

The present invention relates to a polarizing plate, an image display apparatus and a method of manufacturing a polarizing plate.

BACKGROUND ART Conventionally, a polarizing plate is known as one of optical components constituting a liquid crystal display or the like. The polarizing plate generally has a protective film laminated on one side or both sides of the polarizer, so that the mechanical strength, thermal stability and water resistance of the polarizer are complemented. For example, in Patent Document 1, a transparent protective layer (protective film) is formed on one side or both sides of a polarizer as a coating layer of a polymer or as a laminate layer of a film.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-303730

However, with respect to the principal surface of the polarizer in which the protective film is laminated, a desired protective effect can be obtained, but the end portion (side surface) of the polarizer is not sufficiently protected. Actually, when the polarizing plate is adhered to the liquid crystal cell or in subsequent handling, damage or cracks may occur at the end of the polarizer.

Accordingly, it is an object of the present invention to provide a polarizing plate in which end portions of a polarizer are sufficiently protected, and a manufacturing method of the polarizing plate. It is still another object of the present invention to provide an image display device having the above polarizing plate.

The present invention relates to a polarizer comprising a polarizer and a protective film laminated on both surfaces of the polarizer, wherein all of the protective films are formed into a predetermined shape, the protective film is laminated on the entire surface of one side of the polarizer, The polarizing plate being positioned inside the end portion of at least one protective film.

In this polarizing plate, since the end portion of the polarizer is located inside the end portion of at least one of the protective films, the end portion of the polarizer is physically protected. Therefore, when the side surface of the polarizing plate is impacted in the handling of the polarizing plate, damage or cracking of the end of the polarizing plate is prevented.

In the present invention, at least a part of the end portion of the polarizer may be located inside the end portions of both protective films. In this case, since the ends of the polarizer are protected from both surfaces of the polarizer, damage or cracks are prevented from being generated at the ends of the polarizer.

Further, all the ends of the polarizer may be located inside the end portions of at least one of the protective films. In this case, all the ends of the polarizer are protected.

The shape of the polarizing plate of the present invention may be a shape conforming to the shape of a region to which the polarizing plate is adhered, or a square as viewed from a plane, for example. With this shape, it is easy to apply to various articles such as a liquid crystal display device.

The polarizing plate of the present invention is characterized in that a separator is laminated on a side of a protective film on which polarizers are not laminated via a pressure sensitive adhesive layer and a temporary protective film is laminated on the side of the other protective film on which polarizers are not laminated Or may be laminated. In this case, the protective film is prevented from being damaged or abraded, and at the time of using the polarizing plate, the separator is peeled to expose the pressure-sensitive adhesive layer, and the polarizing plate can be bonded to another article by its adhesive force.

The present invention provides an image display apparatus including the polarizing plate. For example, even when a liquid crystal display device in which the polarizing plate is bonded to a liquid crystal cell or the like is formed, the end portion of the polarizer is physically protected.

The present invention also provides a method of manufacturing a polarizing element comprising the steps of laminating a polarizer on a first protective film formed in a predetermined shape so that the entire surface of the first polarizer is covered with the first protective film, A polarizer and a second protective film so that the polarizer is located inside at least one end of at least one of the protective films of the first protective film and the second protective film, The present invention also provides a method for producing a polarizing plate.

The polarizing plate can be produced by this manufacturing method.

According to the present invention, it is possible to provide a polarizing plate in which the ends of the polarizer are sufficiently protected, and a method of manufacturing the polarizing plate. Further, it is possible to provide an image display apparatus including the polarizing plate.

1 is a perspective view of a polarizing plate according to a first embodiment of the present invention.
2 (a) is a cross-sectional view taken along the line IIa-IIa in FIG. (b) is a cross-sectional view taken along line IIb-IIb of FIG.
3 is a cross-sectional view of a polarizing plate according to a second embodiment of the present invention.
4 is a sectional view of the liquid crystal display device.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings do not always coincide with actual ones, and thickness is exaggerated in particular.

≪ First Embodiment >

As shown in Figs. 1 and 2, the polarizing plate 1A of the present embodiment is formed by laminating protective films 3 and 3 on the entire surface of both surfaces of a polarizer 2 formed in a thin film shape. All of the protective films 3 and 3 are formed in the same shape as a rectangular shape in plan view, and this shape also serves as an outer shape of the polarizing plate 1A. That is, the polarizing plate 1A has a rectangular shape in plan view.

The size of the main surface of the polarizing plate 1A, that is, the size of the protective films 3 and 3 can be arbitrarily set in accordance with the application of the polarizing plate 1A. For example, the length of the diagonal line is 5 to 250 cm, 10 to 150 cm, and 12 to 100 cm. The aspect ratio of the adjacent sides, that is, the aspect ratio of the polarizing plate 1A is preferably 1: 9 to 5: 5, more preferably 2: 8 to 5: 5, Is more preferable.

The end 2a of the polarizer 2 is located inside the end portions 3a and 3a of the protective films 3 and 3 over its entire circumference. 2, the side surface of the polarizing plate 1A has a concave shape in which the side surface of the polarizer 2 is inserted into the side surfaces of the protective films 3, 3. It is preferable that the end 2a of the polarizer 2 is located within 1 to 500 占 퐉 of the end portions 3a and 3a of the protective films 3 and 3 and that the end 2a is located inside 1 to 300 占 퐉 More preferably, it is located on the inner side of 1 to 50 mu m. If the end 2a of the polarizer 2 is located in this range, the effect of physically protecting the end 2a of the polarizer 2 is particularly high, and even when the image display device is constituted, the display surface can be secured wide .

It is preferable that the end 2a of the polarizer 2 be located on the inner side with the same length over the entire periphery of the polarizer 2 with respect to the end 3a of the protective film 3. [ For example, when the length is not the same around the entire circumference, it is expected that the polarizing plate 1A will have a complicated curl when the polarizing plate 1A is curled due to a different lamination state depending on the place. It is therefore preferable that the side surface of the polarizing plate 1A has the same length as the side surfaces of the protective films 3 and 3 over the entire circumference thereof.

In this case, the end 2a of the polarizer 2 on the side perpendicular to the direction of the optical axis (absorption axis) is located at the end of the protective film 3, 3 3a, 3a). In general, the side parallel to the optical axis has a high impact resistance, but the side having a slope (for example, 40 DEG or more and 140 DEG or less) with respect to the optical axis or the side perpendicular to the optical axis has low impact resistance. Therefore, if the end 2a of the polarizer 2 is located inside the end portions 3a and 3a of the protective films 3 and 3 on the side perpendicular to the optical axis, the end 2a of the polarizer 2 Protected effects are particularly evident.

It is preferable that a portion of the side surface of the polarizing plate 1A where the side surface of the polarizing film 2 enters the side surface of the protective films 3 and 3 is not filled with another member. That is, the side surface of the polarizer 2 is opened, and is preferably in a state of being in contact with the outside air. For example, if an adhesive or the like described below is exposed in the above-described portion, there is a possibility that other parts of the polarizing plate 1A and peripheral equipment to which the polarizing plate 1A is applied may be contaminated. It is also possible to prevent the polarizing plate 1A and the polarizing plate 2 from being melted by the heat of the protection film 3 and the polarizer 2 during the processing (laser cutting, heat cutting and the like) It is considered that the degree of freedom at the end portion of the polarizing plate 1A is reduced to cause a defect such as wave curl at the end portion. In addition, since the above-mentioned portion, which is an interference part against the impact, is lost, there is a fear that the impact is directly transmitted to the side surface of the polarizer 2. Further, when heat is generated and the molten material such as the protective film 3 or the polarizer 2 is evacuated to the above portion, the polarization performance of the end portion of the polarizing plate 1A may be deteriorated.

The lamination of the polarizer 2 and the protective film 3 may be constituted by bonding the polarizer 2 formed in a film shape and the protective film 3 with an adhesive. 1 and 2, an adhesive layer is not shown.

As the material of the polarizer 2, known materials conventionally used in the production of a polarizing plate can be used, and examples thereof include a polyvinyl alcohol resin, a polyvinyl acetate resin, an ethylene / vinyl acetate (EVA) resin, , And polyester-based resins. Among them, a polyvinyl alcohol-based resin is preferable. In the case of molding in the form of a film for bonding with the protective film 3, it is preferable that the uniaxially stretched film is dyed with iodine or a dichroic dye and then treated with boric acid. As described later, the film-type polarizer can be used by cutting it to an arbitrary size at the time of production of the polarizing plate. The polarizer 2 of the film type produced from these materials has low mechanical strength, thermal stability and water resistance, and particularly low at the end portion of the film. Therefore, cracks and damage are liable to occur at the ends of the polarizer 2 due to handling in the production of the polarizer.

The thickness of the polarizer 2 is preferably 2 to 75 占 퐉, more preferably 2 to 50 占 퐉, and still more preferably 2 to 30 占 퐉.

The protective film 3 is a film for preventing cracks or damage on the main surface or the end portion of the polarizer 2. Here, the term " protective film " refers to a film that is physically stacked at a position closest to the polarizer 2, among the films that can be laminated in various ways on the polarizer 2. [

The protective film 3 can be composed of various transparent resin films known in the field of polarizing plate. Examples thereof include cellulose resins typified by triacetyl cellulose, polyolefin resins exemplified by polypropylene resins, cyclic olefin resins exemplified by norbornene resins, and polymethylmethacrylate resins Representative examples include acrylic resins, polyester resins based on polyethylene terephthalate resins, and the like. Among them, a cellulose-based resin is typical.

The protective film 3 may be a film having no optical function or a film having an optical function such as a retardation film or a brightness enhancement film.

The thickness of the protective film 3 is preferably 5 to 90 탆, more preferably 5 to 80 탆, and still more preferably 5 to 50 탆.

When an adhesive is used in the lamination of the polarizer 2 and the protective film 3, various adhesives conventionally used in the production of a polarizing plate can be used as the adhesive. For example, from the viewpoints of weatherability, refractive index, cationic polymerizability, etc., an epoxy resin which does not contain aromatic rings in the molecule is preferable. Further, it is preferable to cure by irradiation with an active energy ray (ultraviolet ray or heat ray).

As the epoxy resin, for example, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin and the like are preferable. (For example, a cationic polymerization initiator for polymerization by irradiation of ultraviolet rays, a thermal cationic polymerization initiator for polymerization by irradiation of heat rays) or another additive (such as a sensitizer) is added to the epoxy resin, An epoxy resin composition may be prepared and used.

As the adhesive, an acrylic resin such as acrylamide, acrylate, urethane acrylate, or epoxy acrylate, or a polyvinyl alcohol-based water-based adhesive may be used.

The polarizing plate 1A is bonded to one surface or both surfaces of a display cell (image display device) such as a liquid crystal cell. The polarizing plate 1A may further include another optical layer laminated on the protective film 3. [ The other optical layer includes a reflection type polarizing film that transmits a certain kind of polarized light and reflects polarized light exhibiting properties opposite to the polarized type; A film having an antireflection function on the surface and having an antiglare function; A film having a surface antireflection function; Reflective film with reflective function on the surface; A transflective film having both a reflective function and a transmissive function; And a viewing angle compensation film.

The thickness of the polarizing plate 1A composed of the three layers of the polarizer 2 and the protective films 3 and 3 is preferably 10 to 500 mu m, more preferably 10 to 300 mu m, and more preferably 10 to 200 mu m More preferable.

The polarizing plate 1A can be manufactured, for example, as follows. First, the two protective films 3 and 3 are cut out in a rectangular shape from a long film roll made of the material constituting the protective film 3. The size and aspect ratio of the cut rectangular shape are determined according to the application of the polarizing plate 1A. An adhesive is applied to one side of one protective film (first protective film) 3. The region to which the adhesive is applied is not a front surface of the protective film 3 but a region in which the polarizers 2 of film type are laminated.

Next, the polarizer 2 is cut out in a rectangular shape from a long film roll made of the material constituting the polarizer 2. The size of the cut rectangular shape is smaller than that of the protective film 3. The amount to be made smaller is set so as to insert the end 2a of the polarizer 2 inwardly than the end 3a of the protective film 3. [ The cut polarizer 2 of the film type is laminated on the surface of the protective film 3 coated with the adhesive. The lamination here is carried out such that the entire surface of one side of the polarizer 2 is inserted inside the surface of the protective film 3. Here, when viewed from the side of the protective film 3, the polarizer 2 is covered with a protective film. When an active energy ray-curable resin is used as an adhesive, the active energy ray is irradiated to cure the adhesive.

Next, an adhesive is applied to the entire surface of the other side of the polarizer, and the remaining one protective film (second protective film) 3 is laminated. Here, the lamination of the protective film 3 is performed so that the entire surface of the one side of the polarizer 2 is covered by the surface of the protective film 3. In the case where an active energy ray-curable resin is used as an adhesive, the adhesive is cured by irradiating the active energy ray.

The polarizing plate 1A is produced by the above procedure.

In the polarizing plate 1A described above, since the end portion 2a of the polarizer 2 is positioned inside the end portion 3a of the protective film 3, the end portion of the polarizer 2 is physically protected. Therefore, when the side surface of the polarizing plate 1A is impacted, only the end portion 3a of the protective film 3 is impacted in the same handling as in the case of adhering the polarizing plate 1A to a liquid crystal cell, (2) is prevented from being damaged or cracked. This effect is also exhibited when the polarizing plate 1A is bonded again to a liquid crystal cell or the like and then handled again. It also contributes to improvement of the durability of the heat shock test of the polarizing plate 1A.

Since the end 2a of the polarizer 2 is protected by the end portions 3a and 3a of the protective films 3 and 3 laminated on both surfaces of the polarizer 2 in the polarizing plate 1A, Of the liquid crystal cell of the present invention. That is, when the liquid crystal of the liquid crystal cell to which the polarizing plate 1A is adhered has a normal width, the liquid crystal cell itself protects the polarizer 2 from physical impact, The effect becomes smaller. In this case, the ratio of the end 3a of the protective film 3 on the liquid crystal cell side contributing to the protection of the end 2a of the polarizer 2 is increased. When the length of the end 2a of the polarizer 2 located on the inner side of the end portions 3a and 3a of the protective films 3 and 3 is not more than 500 占 퐉, a television screen, a mobile terminal Etc.), it is easy to secure a wide display surface.

Since the end 2a of the polarizer 2 is inside the end 3a of the protective film 3 over its entire periphery, the above effect is exerted over the entire periphery of the polarizing plate 1A.

Further, since the polarizing plate 1A is rectangular in plan view, it can be easily applied to various articles such as a liquid crystal display device.

≪ Second Embodiment >

The polarizing plate of the present invention may further include the separator 4 and the temporary protective film 6 laminated to the laminate of the polarizer 2 and the protective film 3 as shown in Fig.

The polarizing plate 1B of the second embodiment has the same structure as that of the polarizing plate 5 of the first embodiment except that the polarizing plate 1B is provided on one side of the polarizing plate 1A of the first embodiment (that is, on the surface of the one protective film 3 on which the polarizers 2 are not laminated) The separator 4 is laminated on the surface of the substrate 1. A temporary protective film 6 is laminated on the other surface of the polarizing plate 1A (that is, on the surface of the other protective film 3 on which the polarizers 2 are not laminated).

The pressure-sensitive adhesive layer 5 is a layer that functions when the polarizing plate 1B is adhered to another article (for example, a liquid crystal cell). The pressure-sensitive adhesive layer (5) can be composed of acrylic resin, silicone resin, polyester, polyurethane, polyether or the like.

The thickness of the pressure-sensitive adhesive layer 5 is preferably 2 to 500 占 퐉, more preferably 2 to 200 占 퐉, and still more preferably 2 to 50 占 퐉.

As a method of laminating the pressure-sensitive adhesive layer 5 on the protective film 3, for example, a method of applying a solution containing the resin or an arbitrary additive component to the protective film 3 may be applied, Or a method in which a pressure-sensitive adhesive layer 5 is formed with the solution and then laminated on the protective film 3. The end portion 5a of the pressure sensitive adhesive layer 5 preferably coincides with the end portion 3a of the protective film 3 over the entire circumference.

The separator 4 is a peelable film adhered for the purpose of protecting the pressure-sensitive adhesive layer 5 and preventing adhesion of foreign matter or the like. When the polarizing plate 1B is used, the separator 4 is peeled and the pressure-sensitive adhesive layer 5 is exposed. The separator 4 may be made of, for example, a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, or a polyester-based resin such as polyethylene terephthalate. Among them, a stretched film of polyethylene terephthalate is preferable.

The end portion 4a of the separator 4 preferably coincides with the end portion 5a of the pressure-sensitive adhesive layer 5 over the entire circumference. The separator 4 may be subjected to a releasing treatment with a silicone resin or the like on the surface in contact with the pressure-sensitive adhesive layer 5 so that the separator 4 can be easily peeled off when the polarizing plate 1B is used.

The thickness of the separator 4 is preferably 5 to 200 占 퐉, more preferably 5 to 150 占 퐉, and still more preferably 5 to 100 占 퐉.

The temporary protective film 6 is a peelable film and is a film for protecting the surface of the protective film 3 on which the temporary protective film 6 is laminated from damage, abrasion and the like. As the material of the temporary protective film 6, the same material as that of the protective film 3 can be used, and among them, a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate and polybutylene terephthalate is preferable Do.

The temporary protective film 6 may have a pressure-sensitive adhesive layer laminated on the surface of the film as well as a film having a weak adhesive property. The temporary protective film 6 is laminated on the protective film 3 and then bonded to the protective film 3 until use of the polarizing plate 1B and is peeled from the protective film 3 at the time of use. The end portion 6a of the temporary protective film 6 preferably coincides with the end portion 3a of the protective film 3 over the entire circumference.

The thickness of the temporary protective film 6 is preferably 5 to 200 占 퐉, more preferably 5 to 150 占 퐉, and still more preferably 5 to 100 占 퐉.

According to the polarizing plate 1B, the protective film 3 is prevented from being damaged or worn, and when the polarizing plate 1B is used, the separator 4 is peeled off to expose the pressure-sensitive adhesive layer 5, An image display device can be constructed by adhering the organic EL device 1B to other articles such as a liquid crystal cell or an organic EL device.

As shown in Fig. 4, for example, a polarizing plate 1B in which a separator 4 is peeled off is adhered to both surfaces of a liquid crystal cell 8 to form a liquid crystal panel 9, and a backlight (not shown) The surface light source device (not shown) and other members can be combined to fabricate the liquid crystal display device 10. [ On the other hand, a touch panel or the like can be provided on the exposed surface of the temporary protective film 6.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments at all. For example, in the above embodiment, the end 2a of the polarizer 2 is positioned on the inner side of the end portions 3a and 3a of the protective films 3 and 3 over the entire periphery thereof. However, May not extend over the entire periphery of the polarizer 2. In this case, only the portion of the end 2a of the polarizer 2 located inside the end portions 3a and 3a of the protective films 3 and 3 is protected. As one example, only the end 2a of the polarizer 2 (two sides facing the polarizer 2) at the side perpendicular to the direction of the optical axis of the polarizer 2 is located at the end of the protective film 3, 3a, 3a.

In the above embodiment, the polarizer 2 is positioned on the inner side with the same length throughout the entire circumference of the polarizer 2. However, the degree of insertion of the polarizer 2 may be changed depending on the place. For example, when a portion susceptible to impact at the time of handling of the polarizing plate is known in advance, there is a fear that the above-described complicated curl may occur. However, it is desirable to increase the width of the end portion of the polarizer.

The protective film 3 may have the same shape as the polarizer 2. That is, the end 3a of one protective film 3 may coincide with the end 2a of the polarizer 2.

Although the polarizing plates 1A and 1B are rectangular in the above embodiment, the polarizing plates 1A and 1B may have a rectangular shape, for example, a rectangular shape, a trapezoid shape, a parallelogram shape, a square shape, or a circular shape or an elliptical shape. In other words, the polarizers 1A and 1B can be formed in any shape in conformity with the shape of the article to which the polarizers 1A and 1B are bonded. Particularly, But may be a shape conforming to the shape.

1A, 1B: polarizer
2: Polarizer
2a: end of polarizer
3: Protective film
3a: end of protective film
4: Separator
4a: End of separator
5: Pressure-sensitive adhesive layer
5a: end of the pressure-sensitive adhesive layer
6: Temporary protective film
6a: end of temporary protective film
8: liquid crystal cell
9: liquid crystal panel
10: Liquid crystal display device (image display device)

Claims (8)

A polarizer and a protective film laminated on both surfaces thereof,
The protective film is formed in a predetermined shape,
Wherein the protective film is laminated on the entire surface of one side of the polarizer,
And at least a part of the end of the polarizer is positioned inside of at least one end of the protective film. The polarizer according to claim 1, wherein at least a part of the ends of the polarizer is positioned inside the end portions of the protective films on both sides. The polarizer according to claim 1 or 2, wherein all the ends of the polarizer are positioned inside the end portions of at least one of the protective films. The polarizing plate according to any one of claims 1 to 3, wherein the shape in plan view is in conformity with the shape of the region to which the polarizing plate is bonded. The polarizing plate according to any one of claims 1 to 4, wherein the polarizing plate is rectangular in plan view. The polarizing plate according to any one of claims 1 to 5, wherein a separator is laminated on a side of the protective film on which the polarizer is not laminated via a pressure-sensitive adhesive layer,
And a temporary protective film is laminated on the side of the other protective film on which the polarizer is not laminated. An image display apparatus comprising the polarizing plate according to any one of claims 1 to 5. A polarizer is laminated on the first protective film formed in a predetermined shape such that the entire surface of the one surface is covered with the first protective film,
And a second protective film is laminated on the polarizer so as to cover the entire surface of the other side of the other side of the polarizer,
The polarizer and the second protective film are laminated so that the polarizer is located inside the end portion of at least a part of the protective film of at least one of the first protective film and the second protective film Gt;

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