JP6782676B2 - Polarizing plate and liquid crystal display device - Google Patents

Description

The present invention relates to a polarizing plate and a liquid crystal display device.

In recent years, liquid crystal panels for liquid crystal displays have been required to be thinner. Polarizers used in liquid crystal panels are generally brittle and easily torn, so in order to protect them, protective films are attached to both sides of the polarizer to form a polarizing plate (see, for example, Patent Document 1), which is used as a liquid crystal cell. Attach to.

Japanese Patent No. 5743291

Due to the demand for further thinning of the liquid crystal panel, a polarizing plate in which a protective film is attached to only one side of the polarizer is being developed. However, a polarizing plate in which a protective film is attached to only one side of the polarizing element tends to have cracks in the polarizing element during a durability test.

Therefore, an object of the present invention is to provide a polarizing plate having a protective film on only one side of the polarizer, which is less likely to crack during a durability test. Another object of the present invention is to provide a liquid crystal display device provided with the polarizing plate.

The present invention is a polarizing plate including a polarizing element and a protective film laminated on only one side thereof via an adhesive. The protective film is formed into a predetermined shape, and the protective film is Provided is a polarizing plate which is laminated on the entire surface of one side of a polarizing element, and at least a part of the ends of the polarizer is located inside the end of the protective film.

In this polarizing plate, since the end of the polarizer is located inside the end of the protective film, the end of the polarizer is physically protected. Therefore, when the side surface of the polarizing plate is impacted in the handling of the polarizing plate, it is possible to prevent scratches and cracks from being generated at the end of the polarizer. In addition, cracks are unlikely to occur during the durability test.

In this polarizing plate, all the ends of the polarizer may be located inside the edges of the protective film. In this case, all ends of the polarizer are protected.

This polarizing plate is laminated on at least one surface of the protector opposite to the side on which the protective film is laminated and the surface of the protective film opposite to the side on which the protector is laminated. The pressure-sensitive adhesive layer may be further provided, and an optical functional film laminated via the pressure-sensitive adhesive layer may be further provided. Examples of the optical functional film include a reflective polarizer.

The present invention also provides a liquid crystal display device including the above-mentioned polarizing plate. Even when a liquid crystal display device in which the above-mentioned polarizing plate is attached to a liquid crystal cell or the like is configured, the end portion of the polarizer is physically protected.

According to the present invention, it is possible to provide a polarizing plate having a protective film on only one side of the polarizer, which is less likely to crack during a durability test. Further, it is possible to provide a liquid crystal display device provided with the polarizing plate.

It is a perspective view of the polarizing plate of the 1st Embodiment of this invention. (A) is a sectional view taken along line IIa-IIa of FIG. (B) is a sectional view taken along line IIb-IIb of FIG. It is sectional drawing of the polarizing plate of the 2nd Embodiment of this invention. It is sectional drawing of the polarizing plate of another embodiment of this invention. It is sectional drawing of the liquid crystal display device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same parts or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted. In addition, the dimensional ratio of each drawing does not always match the actual one, and in particular, the thickness of the film is exaggerated.

<First Embodiment>
As shown in FIGS. 1 and 2, in the polarizing plate 1A of the present embodiment, a protective film 3 is laminated on one side of a polarizing film (polarizer) 2 formed in a thin film shape via an adhesive layer 4. It is made up of. The polarizing film 2 and the protective film 3 are formed into a rectangular shape in a plan view, and this shape is also the external shape of the polarizing plate 1A.

The polarizing plate 1A is attached to one side or both sides of a display cell (image display element) such as a liquid crystal cell. The polarizing plate 1 is preferably attached to the back surface side of the display cell. The polarizing plate on the back side is more likely to cause dew condensation than the polarizing plate on the visual side, and cracks are more likely to occur in the polarizing film. However, according to the polarizing plate 1 of the present embodiment, cracks are significantly suppressed in the polarizing film 2. can do.

The end portion 2a of the polarizing film 2 is recessed inward (center side of the main surface of the polarizing plate 1) from the end portion 3a of the protective film 3 over the entire circumference thereof. That is, in the cross-sectional view shown in FIG. 2, the side surface of the polarizing plate 1A has a shape in which the side surface of the polarizing film 2 is recessed with respect to the side surface of the protective film 3.

Here, the "edge portion 2a of the polarizing film 2" refers to a side of the side constituting the end surface of the polarizing film 2 that is far from the protective film 3 and perpendicular to the thickness direction of the polarizing plate 1. Further, the "end portion 3a of the protective film 3" refers to a side of the side constituting the end surface of the protective film 3 that is far from the polarizing film 2 and perpendicular to the thickness direction of the polarizing plate 1.

The edge 2a of the polarizing film 2 is preferably located 1 to 500 μm inside the edge 3a of the protective film 3, more preferably 2 to 300 μm inside, and 5 to 50 μm inside. It is more preferable that it is located. Above all, it is preferable that the polarizing film 2 is located inside with the same length over the entire circumference as in the present embodiment. When the end portion 2a of the polarizing film 2 is located in these ranges, the effect of physically protecting the end portion 2a of the polarizing film 2 is particularly high, and a wide display surface is secured even when a liquid crystal display device is configured. can do.

The polarizing film 2 and the protective film 3 are laminated by being bonded to each other via an adhesive layer 4.

As the material of the polarizing film 2, a known material conventionally used for producing a polarizing plate can be used. For example, a polyvinyl alcohol-based resin, a polyvinyl acetate resin, an ethylene / vinyl acetate (EVA) resin, and a polyamide can be used. Examples include resins and polyester resins. Of these, polyvinyl alcohol-based resins are preferable. When the film is formed into 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 will be described later, the film-shaped polarizing element can be cut out to an arbitrary size and used at the time of manufacturing the polarizing plate.

The thickness of the polarizing film 2 is preferably 2 to 30 μm, more preferably 2 to 15 μm, and even more preferably 2 to 10 μm. Generally, the thinner the polarizing film, the more easily cracks occur. However, in the present embodiment, even if the polarizing film 2 is 10 μm or less, cracks can be remarkably prevented.

The protective film 3 is a film that prevents cracks and scratches on the main surface and edges of the polarizing film 2. Here, the "protective film" refers to a film physically laminated at a position closest to the polarizing film 2 among various films that can be laminated on the polarizing film 2.

The protective film 3 can be made of various transparent resin films known in the field of polarizing plates. For example, a cellulose resin typified by triacetyl cellulose, a polyolefin resin typified by a polypropylene resin, a cyclic olefin resin typified by a norbornene resin, and an acrylic typified by a polymethyl methacrylate resin. Examples thereof include polyester-based resins and polyester-based resins typified by polyethylene terephthalate-based resins. Among them, cellulosic resins are typical.

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

As the adhesive constituting the adhesive layer 4, various adhesives conventionally used in the production of polarizing plates can be used. For example, an epoxy resin that does not contain an aromatic ring in the molecule is preferable from the viewpoint of weather resistance, refractive index, cationic polymerization, and the like. Further, those that are cured by irradiation with active energy rays (ultraviolet rays or heat rays) are preferable, and cationic ultraviolet curable adhesives and radical ultraviolet curable adhesives are particularly preferable.

As the epoxy resin, for example, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin and the like are preferable. Polymerization initiators (for example, photocationic polymerization initiators for polymerizing by ultraviolet irradiation, thermal cationic polymerization initiators for polymerizing by heat ray irradiation) and other additives (sensitizers, etc.) for epoxy resins. Can be added to prepare and use an epoxy resin composition for coating.

The resin constituting the radical ultraviolet curable adhesive contains a (meth) acrylic compound having one or more (meth) acryloyloxy groups in the molecule, and is an active energy ray (active energy ray) in the presence of a polymerization initiator. For example, (meth) acrylic compounds that can be polymerized by irradiation with ultraviolet rays, visible light, electron beams, X-rays, etc. can be mentioned.

Further, as the adhesive, a composition containing an acrylic resin such as acrylamide, acrylate, urethane acrylate, or epoxy acrylate, or a water-based adhesive containing a polyvinyl alcohol-based resin can also be used.

The thickness of the polarizing plate 1A composed of the three layers of the polarizing film 2, the adhesive layer 4, and the protective film 3 is preferably 7 to 120 μm, more preferably 10 to 70 μm, and more preferably 10 to 55 μm. Is even more preferable.

The polarizing plate 1A can be manufactured, for example, as follows. First, the protective film 3 is cut into a rectangular shape from a long film roll made of a material constituting the protective film 3. The size and aspect ratio of the rectangle to be cut out shall be determined according to the application target of the polarizing plate 1A. An adhesive is applied to one side of the protective film 3. The area to which the adhesive is applied is not the entire surface of the protective film 3, but the area where the polarizing film 2 is laminated.

Next, the polarizing film 2 is cut into a rectangular shape from a long film roll made of a material constituting the polarizing film 2. The size of the rectangle to be cut out is smaller than the size of the protective film 3. The amount to be reduced is such that the end portion 2a of the polarizing film 2 is desired to be recessed inward from the end portion 3a of the protective film 3. The cut-out film-shaped polarizing film 2 is laminated on the surface of the protective film 3 coated with the adhesive, for example, by using a laminating roll. The lamination here is performed so that the entire surface of one side of the polarizing film 2 is inside the surface of the protective film 3. Here, when viewed from the protective film 3 side, the polarizing film 2 is covered with the protective film 3. When an active energy ray-curable resin is used as the adhesive, the adhesive is cured by irradiating it with active energy rays.

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

In the polarizing plate 1A described above, since the end portion 2a of the polarizing film 2 is located inside the end portion 3a of the protective film 3, the end portion 2a of the polarizing film 2 is physically protected. Therefore, in handling such as when the polarizing plate 1A is attached to a liquid crystal cell, when the side surface of the polarizing plate 1A is impacted, only the end portion 3a of the protective film 3 is impacted, and the polarizing film 2 It prevents scratches and cracks on the edges of the. This effect is also exhibited in further handling after the polarizing plate 1A is attached to a liquid crystal cell or the like. Further, the polarizing plate 1A is less likely to crack in the polarizing film 2 in a durability test such as a heat shock test.

Further, since the edge portion 2a of the polarizing film 2 is protected by the end portion 3a of the protective film 3, the polarizing plate 1A is particularly effective in the recent tendency of narrowing the frame of the liquid crystal cell. That is, when the frame of the liquid crystal cell to which the polarizing plate 1A is attached has a normal width, the liquid crystal cell itself has a function of protecting the polarizing film 2 from being subjected to a physical impact, but the liquid crystal cell has a narrow frame. If there is, the effect of the protection becomes small. In this case, the ratio of the end portion 3a of the protective film 3 on the liquid crystal cell side contributing to the protection of the end portion 2a of the polarizing film 2 increases.

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

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

<Second embodiment>
The polarizing plate 1A may further include another optical functional film. Other optical functional films include reflective polarizers that transmit certain types of polarized light and reflect polarized light that exhibits the opposite properties; anti-glare film with an uneven surface; film with anti-reflection function; Examples thereof include a reflective film having a reflective function on the surface; a semitransparent reflective film having both a reflective function and a transmissive function; a viewing angle compensating film; a retardation film and the like. Hereinafter, an embodiment including a reflective polarizer will be described.

As shown in FIG. 3, the polarizing plate 1B is a reflective polarizing element on the surface of the polarizing plate composed of the polarizing film 2, the adhesive layer 4, and the protective film 3 on the polarizing film 2 side via the pressure-sensitive adhesive layer 5. 6 are laminated.

The size and shape of the reflective polarizing element 6 are the same as the size and shape of the protective film 3, and the end portion thereof projects from the end portion of the polarizing film 2. Any one can be used as the reflective polarizer 6.

The pressure-sensitive adhesive layer 5 can be made of an acrylic resin, a silicone-based resin, polyester, polyurethane, polyether, or the like.

The thickness of the pressure-sensitive adhesive layer 5 is preferably 2 to 50 μm, more preferably 2 to 40 μm, and even more preferably 2 to 30 μm.

As a method of laminating the pressure-sensitive adhesive layer 5 on the polarizing film 2, for example, a method of applying a solution containing the above resin or an arbitrary additive component to the polarizing film 2 may be used, and the pressure-sensitive adhesive layer is applied with the solution on a separately prepared separator. A method of forming 5 and then transferring it to the polarizing film 2 may also be used.

The polarizing plate 1B is provided with yet another pressure-sensitive adhesive layer (not shown) on the reflective polarizing element 6 for the purpose of sticking to another article, and a separator (not shown) is laminated thereto. You may.

The separator is a peelable film that is attached for the purpose of protecting the pressure-sensitive adhesive layer, preventing foreign matter from adhering, and the like, and is peeled off when the polarizing plate 1B is used to expose the pressure-sensitive adhesive layer. The separator can be made of, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate, or the like. Of these, a polyethylene terephthalate stretched film is preferable.

According to the polarizing plate 1B, the polarizing film 2 is prevented from being damaged or worn. Further, the end portion 2a of the polarizing film 2 is further protected by projecting the end portion of the reflective polarizer 6 from the end portion 2a of the polarizing film 2.

The size and shape of the reflective polarizer 6 may be the same as the size and shape of the polarizing film 2 as in the polarizing plate 1C shown in FIG.

When the adhesive layer 5 is further provided on the protective film 3, for example, the polarizing plate 1B is attached to the back surface side (lower side in the drawing) of the liquid crystal cell 8 as shown in FIG. A polarizing plate 1A provided with an adhesive layer 5 on the surface of the polarizing film 2 is attached to the visible side (upper side of the drawing) of the liquid crystal cell 8 to form a liquid crystal panel 9, and a backlight (surface light source device; The liquid crystal display device 10 can be manufactured by combining other members (not shown). The liquid crystal display device usually incorporates two polarizing plates, but the liquid crystal display device of the present embodiment may include at least one polarizing plate.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the above embodiment, the edge 2a of the polarizing film 2 is located inside the edge 3a of the protective film 3 over the entire circumference thereof, but the portion located inside is the polarizing film 2. It does not have to cover the entire circumference of. In this case, as for the end portion 2a of the polarizing film 2, only the portion located inside the end portion 3a of the protective film 3 is protected.

Further, in the above embodiment, it is shown that the polarizing film 2 is located inside with the same length over the entire circumference, but the degree of dent of the polarizing film 2 may be changed depending on the location. For example, when a portion that is susceptible to impact during handling of the polarizing plate is known in advance, it is preferable to increase the recessed width of the end portion of the polarizing film at that portion.

Further, in the above embodiment, an example in which the polarizing plates 1A and 1B are rectangular in a plan view is shown, but other quadrangles such as trapezoids, parallelograms, squares, etc., as well as circular and elliptical shapes are used. May be good. That is, the polarizing plates 1A and 1B can have any shape according to the shape of the article to which the polarizing plates 1A and 1B are attached.

Further, in the second embodiment, the adhesive layer 5 is laminated on the polarizing film 2 side, but the adhesive layer 5 is also laminated on the protective film 3 side, and other optical functional layers are laminated. May be.

Hereinafter, the contents of the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

(1) Preparation of Polarizing Film A polyvinyl alcohol film having an average degree of polymerization of about 2400, a saponification degree of 99.9 mol% or more and a thickness of 20 μm was uniaxially stretched about 4 times by a dry method. After immersing in pure water at 40 ° C. for 1 minute while maintaining the tension of stretching, it was immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.1 / 5/100 at 28 ° C. for 60 seconds. .. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 10.5 / 7.5 / 100 at 68 ° C. for 300 seconds. Subsequently, the film was washed with pure water at 5 ° C. for 5 seconds and then dried at 70 ° C. for 180 seconds to obtain a polarizing film (polarizer) in which iodine was adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film. The thickness of the polarizing film was 7 μm.

(2) Preparation of Adhesive (2-1) Water-based Adhesive Polyvinyl alcohol powder (trade name "KL-318" manufactured by Kuraray Co., Ltd., average degree of polymerization of 1800) is dissolved in hot water at 95 ° C. to a concentration of 3 weight. % Polyvinyl alcohol aqueous solution was prepared. A cross-linking agent (trade name "Smiley's Resin 650" manufactured by Taoka Chemical Industry Co., Ltd.) was mixed with the obtained aqueous solution at a ratio of 1 part by mass with respect to 2 parts by mass of polyvinyl alcohol powder to obtain an aqueous adhesive.

(2-2) Cationic UV Curable Adhesive The following components were mixed and defoamed to prepare an UV curable adhesive. As the photocationic polymerization initiator, one obtained in the form of a 50% propylene carbonate solution was used. The blending amount (2.25 parts by mass) shown below is the amount of solid content.
・ 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate… 75 parts by mass ・ 1,4-butanediol diglycidyl ether… 20 parts by mass ・ 2-Ethylhexylglycidyl ether… 5 parts by mass ・ Triarylsulfonium hexafluoro Phosphate-based photocationic polymerization initiator ... 2.25 parts by mass

(2-3) Radical-based UV-curable adhesive The following components were mixed and defoamed to prepare an UV-curable adhesive.
・ Bis (3-ethyl-3-oxetanylmethyl) ether (Aron oxetane OXT-221, manufactured by Toa Synthetic Co., Ltd.)… 15 parts by mass ・ Tricyclodecanedimethanol diacrylate (A-DCP, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) )… 50 parts by mass ・ 2-Hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173, manufactured by Ciba Specialty Chemicals) (photoradical polymerization initiator)… 2.25 parts by mass

(3) Fabrication of single-sided protective polarizing plate (when using water-based adhesive)
A single-sided protective polarizing plate with a release film was produced by the following procedure. A protective film having a size of 120 mm × 70 mm was cut out from a roll of the polarizing film obtained in (1) above and a protective film (Zeonor film Zeonoa film ZF14-023, thickness 23 μm) manufactured by Nippon Zeon Corporation. At this time, the polarizing film was adjusted to be slightly smaller than the protective film (the degree of "slightly" will be described later). The protective film is corona-treated, and a release film (trade name "KC8UX2MW", which is a TAC film manufactured by Konica Minolta Opto Co., Ltd., thickness 80 μm, no saponification treatment) is separately cut out to form a protective film and a polarizing film. , The release film was laminated in this order.

Next, the water-based adhesive obtained in (2-1) above is injected between the polarizing film and the protective film, and pure water is injected between the polarizing film and the release film and passed between the bonding rolls. A laminated film composed of a protective film, a water-based adhesive layer, a polarizing film, pure water, and a release film. Subsequently, the laminated film was heat-treated at 80 ° C. for 300 seconds in a drying device to dry the aqueous adhesive layer and volatilize and remove the pure water interposed between the polarizing film and the release film. A single-sided protective polarizing plate with a release film was obtained. The release film was peeled off from the single-sided protective polarizing plate with a release film to obtain a single-sided protective polarizing plate.

(4) Fabrication of single-sided protective polarizing plate (when using UV-curable adhesive)
A protective film was cut out one by one from a roll of the polarizing film obtained in (1) above and a protective film (Zeon Corporation Zeonoa Film Zeonoa Film ZF14-023, thickness 23 μm). At this time, the polarizing film was adjusted to be smaller than the protective film. The protective film was subjected to corona treatment, and the protective film and the polarizing film were laminated in this order.

Next, the ultraviolet curable adhesive obtained in (2-2) or (2-3) above is injected between the polarizing film and the protective film, and the protective film / ultraviolet curable adhesive is passed between the bonding rolls. A laminated film composed of an agent / polarizing film was used. Subsequently, UV irradiation was performed from the protective film side using a UV irradiation device to cure the ultraviolet curable adhesive to obtain a single-sided protective polarizing plate.

(5) Preparation of Single-sided Protective Polarizing Plate with Brightness-Improved Film Brightness-improving film (3M stock) on the polarizing film surface of the single-sided protective polarizing plate obtained in (3) and (4) above with an acrylic pressure-sensitive adhesive. A single-sided protective polarizing plate with a brightness-improving film was obtained by laminating (trade name "APF"), which is a reflective polarizer manufactured by the company. At this time, the size of the brightness improving film was the same as the size of the polarizing plate, and the stretching axis of the brightness improving film was parallel to the stretching direction of the polarizing film and bonded.

(6) Preparation of Polarizing Plate with Acrylic Pressure-Sensitive Adhesive Acrylic pressure-sensitive adhesive with separator film is attached to the brightness-enhancing film surface of the single-sided protective polarizing plate with brightness-enhancing film obtained in (5) above. A polarizing plate with an acrylic pressure-sensitive adhesive was obtained.

(7) Heat shock test A heat shock test was conducted as a durability test. A sample for the heat shock test was prepared by the following procedure.

After the sample obtained in (6) above is attached to a non-alkali glass plate (“Eagle-XG” manufactured by Corning Inc.), pressure treatment is performed for 20 minutes in an autoclave under the conditions of a temperature of 50 ° C. and a pressure of 5 MPa. Then, the mixture was allowed to stand for one day in an atmosphere having a temperature of 23 ° C. and a relative humidity of 60%. After that, using a cold shock tester "TSA-301L-W" manufactured by ESPEC CORPORATION, the low temperature side was -40 ° C [holding time 30 minutes], the room temperature was 23 ° C [holding time 5 minutes], and the high temperature side was 85 ° C [holding time]. A durability test was conducted in which the test tank was stored in the order of [30 minutes] for 12 cycles under the conditions set to change. After that, the sample was taken out and it was confirmed whether or not there was a crack-like appearance defect.

(8) Examples and Comparative Examples The following shows the results of performing "(7) heat shock test" on the polarizing plates prepared according to the procedures of (1) to (6) above.

[Example 1]
Cut out so that the size of the polarizing film is 0.1 mm smaller in both the vertical and horizontal directions than the size of the protective film, and the edge of the polarizing film is 0 on each side with respect to the edge of the protective film. A polarizing plate was prepared using an aqueous adhesive, adjusted to be located inside .05 mm, and a heat shock test was carried out. As a result, no cracks were observed in the polarizing film.

[Example 2]
The size of the polarizing film is cut out so that the total width in the vertical direction and the horizontal direction is 0.1 mm smaller than the size of the protective film, and the edge of the polarizing film is 0 on each side with respect to the edge of the protective film. A polarizing plate was prepared using a cationic ultraviolet curable adhesive, adjusted to be located inside .05 mm, and a heat shock test was carried out. As a result, no cracks were observed in the polarizing film.

[Example 3]
The size of the polarizing film is cut out so that the total width in the vertical direction and the horizontal direction is 0.1 mm smaller than the size of the protective film, and the edge of the polarizing film is 0 on each side with respect to the edge of the protective film. A polarizing plate was prepared using a radical ultraviolet curable adhesive, adjusted to be located inside .05 mm, and a heat shock test was carried out. As a result, no cracks were observed in the polarizing film.

[Example 4]
A polarizing plate was prepared in the same manner as in Example 1 except that triacetyl cellulose (manufactured by Konica Minolta Opto Co., Ltd., zero tack, thickness 20 μm) obtained by saponifying the protective film was used, and a heat shock test was carried out. As a result, no cracks were observed in the polarizing film.

[Example 5]
A polarizing plate was prepared in the same manner as in Example 2 except that triacetyl cellulose (manufactured by Konica Minolta Opto Co., Ltd., zero tack, thickness 20 μm) obtained by saponifying the protective film was used, and a heat shock test was carried out. As a result, no cracks were observed in the polarizing film.

[Example 6]
A polarizing plate was prepared in the same manner as in Example 3 except that triacetyl cellulose (manufactured by Konica Minolta Opto Co., Ltd., zero tack, thickness 20 μm) obtained by saponifying the protective film was used, and a heat shock test was carried out. As a result, no cracks were observed in the polarizing film.

[Comparative Example 1]
Both the polarizing film and the protective film are cut out to a size of 130 mm × 80 mm, a polarizing plate is prepared using an aqueous adhesive, and then each side is cut by 5 mm with a super cutter, molded into 120 mm × 70 mm, and subjected to a heat shock test. Carried out. As a result, cracks were generated at the edges of the polarizing film.

[Comparative Example 2]
Both the polarizing film and the protective film were cut out to a size of 130 mm × 80 mm, a polarizing plate was prepared using a cationic ultraviolet curable adhesive, and then each side was cut by 5 mm with a super cutter and molded into 120 mm × 70 mm. A heat shock test was performed. As a result, cracks were generated at the edges of the polarizing film.

[Comparative Example 3]
Both the polarizing film and the protective film are cut out to a size of 130 mm × 80 mm, a polarizing plate is prepared using a radical ultraviolet curable adhesive, and then each side is cut by 5 mm with a super cutter and molded into 120 mm × 70 mm. A heat shock test was performed. As a result, many cracks were generated at the edges of the polarizing film.

[Comparative Example 4]
The size of the polarizing film is cut out so that the total width in the vertical direction and the horizontal direction is 0.1 mm larger than the size of the protective film, and the edge of the polarizing film is 0 with respect to the edge of the protective film on each side. A polarizing plate was prepared using an aqueous adhesive, adjusted to be located .05 mm outside, and a heat shock test was carried out. As a result, cracks were generated at the edges of the polarizing film.

[Comparative Example 5]
The size of the polarizing film is cut out so that the total width in the vertical direction and the horizontal direction is 0.1 mm larger than the size of the protective film, and the edge of the polarizing film is 0 with respect to the edge of the protective film on each side. A polarizing plate was prepared using a cationic ultraviolet curable adhesive, adjusted to be located .05 mm outside, and a heat shock test was carried out. As a result, cracks were generated at the edges of the polarizing film.

[Comparative Example 6]
The size of the polarizing film is cut out so that the total width in the vertical direction and the horizontal direction is 0.1 mm larger than the size of the protective film, and the edge of the polarizing film is 0 with respect to the edge of the protective film on each side. A polarizing plate was prepared using a radical ultraviolet curable adhesive, adjusted to be located .05 mm outside, and a heat shock test was carried out. As a result, many cracks were generated at the edges of the polarizing film.

The present invention can be used, for example, as a component of a liquid crystal panel.

1A, 1B, 1C ... polarizing plate, 2 ... polarizing film (polarizer), 2a ... edge of polarizing film, 3 ... protective film, 3a ... end of protective film, 4 ... adhesive layer (adhesive), 5 ... Adhesive layer, 6 ... Reflective polarizer (optical functional film), 8 ... Liquid crystal cell, 9 ... Liquid crystal panel, 10 ... Liquid crystal display device.

Claims (4)

It comprises a polarizer and a protective film laminated on only one side thereof with an adhesive.
The polarizer has a thickness of 10 μm or less and has a thickness of 10 μm or less.
The protective film is formed into a predetermined shape and has a predetermined shape.
The protective film is laminated on the entire surface of one side of the polarizer.
All ends of the polarizer are located 50 to 500 μm inside the edges of the protective film .
It was laminated on at least one surface of the protector opposite to the side on which the protective film was laminated and on the surface of the protective film opposite to the side on which the protector was laminated. With an additional adhesive layer,
A polarizing plate further comprising a reflective polarizing element laminated via the pressure-sensitive adhesive layer . The polarizing plate according to claim 1, wherein the polarizer has a thickness of 7 μm or less. The polarizing plate according to claim 1 or 2 , wherein the adhesive interposed between the polarizer and the protective film is one that is cured by irradiation with active energy rays or is an aqueous adhesive . A liquid crystal display device including the polarizing plate according to any one of claims 1 to 3 .

Images