KR102535072B1 - Polarizing plate and liquid crystal display device - Google Patents

Abstract

[Problem] To provide a polarizing plate having a protective film on only one side of the polarizer, which is hardly cracked during an endurance test.
[Means of Solution] A polarizing plate 1A includes a polarizer 2 and a protective film 3 laminated on only one side thereof via an adhesive 4. The protective film 3 is molded into a predetermined shape, the protective film 3 is laminated on the entire surface of one side of the polarizer 2, and at least a portion of the end portion 2a of the polarizer 2 is a protective film ( It is located inside the edge part 3a of 3). Due to such an end shape, it is difficult for the end 2a of the polarizer 2 to be exposed to physical stimuli from the external environment.

Description

Polarizing plate and liquid crystal display {POLARIZING PLATE AND LIQUID CRYSTAL DISPLAY DEVICE}

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

In recent years, thinning of the liquid crystal panel for liquid crystal displays is requested|required. Since polarizers used in liquid crystal panels are generally brittle and easily torn, a polarizing plate is formed by bonding protective films to both sides of the polarizer to protect it (see Patent Document 1, for example), and this is adhered to the liquid crystal cell.

Patent Document 1: Japanese Patent No. 5743291

In response to the demand for further thinning of the liquid crystal panel, development of a polarizing plate in which a protective film is bonded to only one side of the polarizer is being performed. However, a polarizing plate in which a protective film is bonded only to one side of the polarizer tends to easily cause cracks in the polarizer during an endurance test.

Accordingly, 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 unlikely to crack during an endurance test. Moreover, it aims at providing the liquid crystal display device provided with the said polarizing plate.

The present invention is a polarizing plate provided with a polarizer and a protective film laminated on only one side thereof through an adhesive, wherein the protective film is molded into a predetermined shape, the protective film is laminated on the entire surface of one side of the polarizer, Provided is a polarizing plate in which at least one end portion of the polarizer is located inside the end portion 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 handling the polarizing plate, when the side surface of the polarizing plate receives an impact, scratches or cracks are prevented from being formed at the end portion of the polarizing plate. Moreover, it is hard to generate a crack also at the time of an endurance test.

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

This polarizing plate further comprises a pressure-sensitive adhesive layer laminated on at least one surface of the surface opposite to the side on which the protective film in the polarizer is laminated, and the surface on the opposite side to the side on which the polarizer in the protective film is laminated. It may be present, and it may further be equipped with the optical function film laminated|stacked via this adhesive layer. As an optical function film, a reflection type polarizer is mentioned.

In addition, the present invention provides a liquid crystal display device provided with the polarizing plate. Even in the case of constructing a liquid crystal display device in which the polarizing plate is adhered to a liquid crystal cell or the like, the end portion of the polarizer is physically protected.

ADVANTAGE OF THE INVENTION According to this invention, as a polarizing plate provided with the protective film only on one surface of a polarizer, it is possible to provide a polarizing plate in which cracks do not easily occur during an endurance test. Moreover, a liquid crystal display device provided with the said polarizing plate can be provided.

1 is a perspective view of a polarizing plate according to a first embodiment of the present invention.
FIG. 2(A) is a cross-sectional view IIa-IIa of FIG. 1 . (B) is a IIb-IIb cross-sectional view of FIG. 1 .
3 is a cross-sectional view of a polarizing plate according to a second embodiment of the present invention.
4 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.
5 is a cross-sectional view of a liquid crystal display device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code|symbol is attached|subjected to the same part or an equivalent part, and overlapping description is abbreviate|omitted. In addition, the dimension ratio of each drawing does not necessarily correspond to an actual thing, and is exaggerated especially about thickness.

<First Embodiment>

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

1 A of polarizing plates are bonded to one surface or both surfaces of display cells (image display elements), such as a liquid crystal cell. The polarizing plate 1 is preferably bonded to the back side of the cell for display. Compared to the polarizing plate on the viewing side, condensation and the like are more likely to occur in the polarizing plate on the back side than the polarizing plate on the visual side, and cracks easily occur in the polarizing film. can

The end portion 2a of the polarizing film 2 is dented on the inner side (center side of the main surface of the polarizing plate 1) than the end portion 3a of the protective film 3 over the entire periphery. That is, in the cross-sectional view shown in FIG. 2 , the side surface of the polarizing plate 1A has a shape where the side surface of the polarizing film 2 is recessed with respect to the side surface of the protective film 3 .

Here, the "end part 2a of the polarizing film 2" is on the far side from the protective film 3 among the sides constituting the end face of the polarizing film 2, and refers to the side perpendicular to the thickness direction of the polarizing plate 1 . In addition, the "end part 3a of the protective film 3" is the side farthest from the polarizing film 2 and perpendicular to the thickness direction of the polarizing plate 1 among the sides constituting the end face of the protective film 3. say

The end portion 2a of the polarizing film 2 is preferably located 1 to 500 μm inside of the end portion 3a of the protective film 3, more preferably located 2 to 300 μm inside, and is located 2 to 300 μm inside. It is more preferably located inside 100 μm, more preferably located inside 5 to 50 μm, and even more preferably located inside 5 to 30 μm. Especially, like this embodiment, it is preferable to be located in the inner side with the same length over the entire circumference of the polarizing film 2. When the end portion 2a of the polarizing film 2 is located within this range, the effect of physically protecting the end portion 2a of the polarizing film 2 is particularly high, and a wide display surface can be secured even when a liquid crystal display device is configured. can

The polarizing film 2 and the protective film 3 are bonded and laminated via the adhesive layer 4 .

As the material of the polarizing film 2, known materials conventionally used in the manufacture of polarizing plates can be used, such as polyvinyl alcohol-based resins, polyvinyl acetate resins, ethylene/vinyl acetate (EVA) resins, polyamide resins, Polyester-type resin etc. are mentioned.

Among them, polyvinyl alcohol-based resins are preferable. When forming into a film shape for bonding with the protective film 3, it is preferable to dye the uniaxially stretched film with iodine or a dichroic dye, and then to treat with boric acid. As will be described later, a film-type polarizer can be cut into an arbitrary size and used at the time of producing a polarizing plate.

The thickness of the polarizing film 2 is preferably 2 to 30 μm, more preferably 2 to 15 μm, and still more preferably 2 to 10 μm. Generally, the thinner the polarizing film, the more likely it is to crack, but in this embodiment, cracks can be remarkably prevented even if the thickness of the polarizing film 2 is 10 μm or less.

The protective film 3 is a film that prevents cracking or damage to the main surface or end portion of the polarizing film 2 . Here, the "protective film" refers to a film that is physically laminated at a position closest to the polarizing film 2 among films that can be laminated on the polarizing film 2 in various ways.

The protective film 3 can be composed of various transparent resin films known in the field of polarizing plates. For example, a cellulose-based resin with triacetyl cellulose as a representative example, a polyolefin-based resin with a polypropylene-based resin as a representative example, a cyclic olefin-based resin with a norbornene-based resin as a representative example, and a polymethyl methacrylate-based resin as a representative example. Polyester-type resin etc. which make acrylic resin made into an example and a polyethylene terephthalate-type resin a typical example are mentioned. Among them, a cellulose-based resin is representative.

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

As the adhesive constituting the adhesive layer 4, various adhesives conventionally used in the manufacture of polarizing plates can be used. For example, from the viewpoint of weather resistance, refractive index, cationic polymerization, etc., an epoxy resin containing no aromatic ring in the molecule is preferable. Further, curing by irradiation with active energy rays (ultraviolet rays or heat rays) is preferred, and cationic UV curable adhesives and radical UV curable adhesives are particularly preferred.

As an epoxy resin, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. are preferable, for example. To the epoxy resin, a polymerization initiator (for example, a photocationic polymerization initiator for polymerization by ultraviolet irradiation, a thermal cationic polymerization initiator for polymerization by heat ray irradiation) and other additives (sensitizer, etc.) are further added, and the epoxy for coating is applied. A resin composition can be prepared and used.

As the resin constituting the radical ultraviolet curable adhesive, a (meth)acrylic compound having at least one (meth)acryloyloxy group in the molecule is contained, and in the presence of a polymerization initiator, active energy rays (eg, ultraviolet rays, and (meth)acrylic compounds that can be polymerized by irradiation with visible light, electron beams, X-rays, etc.).

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 resin may be used.

The thickness of the polarizing plate 1A composed of 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 -55 μm.

1 A of polarizing plates 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 . It is assumed that the size and aspect ratio of the rectangle to be cut out are 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 where 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 rectangle from the long film roll made of the material constituting the polarizing film 2 . The size of the rectangle to be cut is made smaller than the size of the protective film 3 . As the amount to be reduced, the portion 2a of the polarizing film 2 is intended to be dented inward from the end 3a of the protective film 3. The cut-out film-shaped polarizing film 2 is laminated on the surface of the protective film 3 to which the adhesive has been applied, using, for example, a bonding roll. The lamination here is performed so that the entire surface of one surface of the polarizing film 2 may enter the inner side of 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 . In the case where an active energy ray-curable resin is used as the adhesive, the adhesive is cured by irradiation with an active energy ray.

1 A of polarizing plates are manufactured by the above procedure.

In the polarizing plate 1A described above, since the end 2a of the polarizing film 2 is located inside the end 3a of the protective film 3, the end 2a of the polarizing film 2 is physically are protected Therefore, in handling such as when the polarizing plate 1A is adhered to, for example, 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, thereby polarizing the polarized light. Damage or cracking to the end of the film 2 is prevented. This effect is exhibited also in another handling after attaching the polarizing plate 1A to a liquid crystal cell or the like. In addition, the polarizing plate 1A is less likely to crack in the polarizing film 2 in durability tests such as heat shock tests.

In the polarizing plate 1A, since the edge 2a of the polarizing film 2 is protected by the edge 3a of the protective film 3, especially in recent years, the frame of the liquid crystal cell tends to be narrow. The effect is exhibited favorably. That is, when the frame of the liquid crystal cell to which the polarizing plate 1A is adhered has a normal width, the liquid crystal cell itself has a function of protecting the polarizing film 2 from being subjected to physical impact, but if the frame of the liquid crystal cell is narrow, the protection is less effective. In this case, the ratio at which the end portion 3a of the protective film 3 on the side of the liquid crystal cell contributes to protection of the end portion 2a of the polarizing film 2 increases.

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

In addition, since the polarizing plate 1A has a rectangular shape in plan view, it is easy to apply to various articles such as a liquid crystal display device.

<Second Embodiment>

1 A of polarizing plates may further be equipped with another optical function film. Other optically functional films include a reflective polarizer that transmits a certain type of polarized light and reflects polarized light exhibiting properties opposite to that; A film having an anti-glare function having a concavo-convex shape on the surface; Films with surface antireflection; a reflective film having a reflective function on its surface; A transflective reflective film having both a reflective function and a transmissive function; viewing angle compensation film; Retardation film etc. are mentioned. Hereinafter, an embodiment provided with a reflective polarizer will be described.

As shown in FIG. 3 , the polarizing plate 1B is composed of the polarizing film 2, the adhesive layer 4, and the protective film 3, and the pressure-sensitive adhesive layer 5 is placed on the surface of the polarizing plate on the polarizing film 2 side. ) through which the reflective polarizer 6 is stacked.

The size and shape of the reflective polarizer 6 are the same as those of the protective film 3, and its end protrudes from the end of the polarizing film 2. As the reflective polarizer 6, any one can be used.

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 50 μm, more preferably 2 to 40 μm, still 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-described resin and optional additive components to the polarizing film 2 may be used, and the solution is placed on a separately prepared separator. After forming the pressure-sensitive adhesive layer 5 by , a method of transferring this to the polarizing film 2 may be used.

The polarizing plate 1B may further include a separate pressure-sensitive adhesive layer (not shown) on the reflective polarizer 6 for the purpose of adhering to other articles, and a separator (not shown) may be laminated thereon. .

The separator is a peelable film that is bonded for the purpose of protecting the pressure-sensitive adhesive layer or preventing adhesion of foreign matter, etc., and is peeled off during use of the polarizing plate 1B to expose the pressure-sensitive adhesive layer. The separator can be composed 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. Especially, the stretched film of polyethylene terephthalate is preferable.

According to the polarizing plate 1B, the polarizing film 2 is prevented from being damaged or abraded. Further, the edge 2a of the polarizing film 2 is further protected by the end of the reflective polarizer 6 protruding beyond the end 2a of the polarizing film 2 .

In addition, 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. 4 .

In the case where the pressure-sensitive adhesive layer 5 is further provided on the protective film 3, as shown in FIG. 5, for example, the polarizing plate 1B is placed on the back side of the liquid crystal cell 8 (lower side in the illustration). On the other hand, the polarizing plate 1A having the pressure-sensitive adhesive layer 5 on the surface of the polarizing film 2 side is adhered to the visual side of the liquid crystal cell 8 (upper side in the figure) to form a liquid crystal panel 9, The liquid crystal display device 10 can be produced by combining a backlight (surface light source device; not shown) and other members here. Moreover, although the polarizing plate of 2 sheets is normally inserted in the liquid crystal display device, as a liquid crystal display device of this embodiment, what is necessary is just to be equipped with at least 1 polarizing plate.

As mentioned above, although the preferable embodiment of this invention was described, this invention is not limited to the said embodiment at all. For example, in the above embodiment, the end portion 2a of the polarizing film 2 is located inside the end portion 3a of the protective film 3 over the entire circumference, but the portion located inside is the polarizing film It is not necessary to span the entire circumference of (2). In this case, as for the edge part 2a of the polarizing film 2, only the part located inside the edge part 3a of the protective film 3 is protected.

In addition, in the above embodiment, the state of being located on the inner side with the same length over the entire circumference of the polarizing film 2 was shown, but the degree of dents in the polarizing film 2 may be changed depending on the location. For example, in the case where the portion that is easily subjected to impact during handling of the polarizing plate is known in advance, it is preferable to increase the groove width of the end portion of the polarizing film in that portion.

In the above embodiment, the polarizing plates 1A and 1B are rectangular in plan view, but may be other rectangular shapes such as trapezoid, parallelogram, square, etc., as well as circular or elliptical shapes. That is, the polarizing plates 1A, 1B can have any shape according to the shape of the article to which the polarizing plates 1A, 1B are bonded.

Further, in the second embodiment, the aspect in which the pressure-sensitive adhesive layer 5 was laminated on the polarizing film 2 side was shown, but the pressure-sensitive adhesive layer 5 was also laminated on the protective film 3 side, and another optical function layer was laminated. can be done with

[Example]

Hereinafter, the contents of the present invention will be described in more detail by way of Examples and Comparative Examples. In addition, this invention is not limited to the following example.

(1) Production of polarizing film

A polyvinyl alcohol film having an average degree of polymerization of about 2400 and a degree of saponification of 99.9 mol% or more and a thickness of 20 μm was uniaxially stretched about 4 times in a dry method. It was immersed in pure water at 40°C for 1 minute while maintaining the tension of stretching, and then 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. Thereafter, it was immersed at 68°C for 300 seconds in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 10.5/7.5/100. Subsequently, it was washed with pure water at 5°C for 5 seconds and 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: 1800) was dissolved in hot water at 95°C to prepare a polyvinyl alcohol aqueous solution having a concentration of 3% by weight. A crosslinking agent (trade name "Sumiresin 650" manufactured by Taoka Chemical Industry Co., Ltd.) was mixed with the obtained aqueous solution at a ratio of 1 part by mass to 2 parts by mass of polyvinyl alcohol powder to obtain a water-based adhesive.

(2-2) cationic UV curable adhesive

Each of the following components was mixed and defoamed to prepare an ultraviolet curable adhesive. Moreover, what was obtained in the form of a 50% propylene carbonate solution was used for the photocationic polymerization initiator. The blending amount (2.25 parts by mass) shown below is the amount of solid content.

ㆍ3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate: 75 parts by mass

ㆍ1,4-butanediol diglycidyl ether: 20 parts by mass

ㆍ2-ethylhexyl glycidyl ether: 5 parts by mass

ㆍTriarylsulfonium hexafluorophosphate-based photocationic polymerization initiator: 2.25 parts by mass

(2-3) radical UV curable adhesive

Each of the following components was mixed and defoamed to prepare an ultraviolet curable adhesive.

ㆍBis (3-ethyl-3-oxetanylmethyl) ether (Aronoxetane OXT-221, manufactured by Toa Synthesis Co., Ltd.): 15 parts by mass

ㆍTricyclodecane dimethanol 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 Chemical Co., Ltd.) (photoradical polymerization initiator): 2.25 parts by mass

(3) Fabrication of one-sided protective polarizer (when using water-based adhesive)

A one-sided protective polarizing plate with a peeling film was produced in the following procedure. Each protective film was cut out from the roll of the polarizing film obtained in (1) above and the protective film (Nippon Zeon Co., Ltd. Zeonoa Film Zeonoa Film ZF14-023, thickness: 23 µm) to a size of 120 mm x 70 mm. At this time, the polarizing film was adjusted to be slightly smaller than the protective film (the degree of "slightly" will be described later). Corona treatment is applied to the protective film, and a release film (trade name "KC8UX2MW", which is a TAC film manufactured by Konica Minolta Opto Co., Ltd., thickness 80 μm, not saponified) is separately cut, and the protective film, polarizing film, and peeling The films were laminated in order.

Next, while injecting the water-based adhesive obtained in the above (2-1) between the polarizing film and the protective film, injecting pure water between the polarizing film and the release film and passing it between bonding rolls, the protective film/water-based adhesive layer/ It was set as the laminated|multilayer film which consists of polarizing film/pure water/peeling film. Then, while the water-based adhesive layer is dried by heat-processing the laminated film at 80°C for 300 seconds in a drying device, pure water interposed between the polarizing film and the peeling film is removed by volatilization, and the peeling film is attached to one side. A protective polarizer was obtained. The peeling film was peeled from the single-sided protective polarizing plate with a peeling film, and the single-sided protective polarizing plate was obtained.

(4) Fabrication of one-sided protective polarizing plate (when using UV-curable adhesive)

Each protective film was cut out from the roll of the polarizing film obtained in said (1) and the protective film (Nippon Zeon Co., Ltd. Zeonoa film Zeonoa film ZF14-023, thickness 23 micrometers). At this time, the polarizing film was adjusted to be smaller than the protective film. Corona treatment was given to the protective film, and the protective film and the polarizing film were laminated|stacked in this order.

Then, the UV curable adhesive obtained in (2-2) or (2-3) above is injected between the polarizing film and the protective film, and passed between bonding rolls to form a laminated film composed of the protective film/UV curable adhesive/polarizing film. did. Subsequently, by performing UV irradiation from the protective film side using a UV irradiation device, the ultraviolet curable adhesive was cured and a single-sided protective polarizing plate was obtained.

(5) Fabrication of one-sided protective polarizer with luminance enhancement film

A brightness enhancing film (reflection type polarizer manufactured by 3M Co., Ltd., trade name "APF") is bonded to the polarizing film side of the one-sided protective polarizing plate obtained in (3) and (4) above through an acrylic pressure-sensitive adhesive to protect one side with the brightness enhancing film. A polarizer was obtained. At this time, the size of the brightness enhancement film was made the same as the size of the polarizing plate, and the stretching axis of the brightness enhancement film was made parallel to the stretching direction of the polarizing film and bonded.

(6) Production of polarizing plate with acrylic pressure-sensitive adhesive

An acrylic pressure-sensitive adhesive with a separator film was bonded to the surface of the single-sided protective polarizing plate with a brightness-enhancing film obtained in (5) above to obtain a polarizing plate with an acrylic pressure-sensitive adhesive.

(7) Heat shock test

A heat shock test was conducted as an endurance test. Samples for heat shock tests were produced in the following procedure.

After the sample obtained in (6) was adhered to an alkali-free glass plate (“Eagle-XG” manufactured by Corning Co., Ltd.), pressure treatment was performed for 20 minutes under conditions of a temperature of 50° C. and a pressure of 5 MPa in an autoclave, followed by temperature It was left to stand in an atmosphere of 23°C and 60% relative humidity for one day. After that, with a cold heat shock tester "TSA-301L-W" manufactured by Espec Co., Ltd., low temperature side -40 ° C [holding time 30 minutes], normal temperature 23 ° C [holding time 5 minutes], high temperature side 85 ° C [holding time 30 minutes] minute], a durability test was conducted in which the inside of the test tank was stored for 12 cycles under conditions set to change. Then, the sample was taken out and the presence or absence of a crack-shaped appearance problem was confirmed.

(8) Examples and Comparative Examples

Hereinafter, the result of having implemented "(7) heat shock test" about the polarizing plate produced according to the implementation procedure of said (1)-(6) is shown.

[Example 1]

The size of the polarizing film is cut so that both the vertical and horizontal widths are 0.1 mm smaller than the size of the protective film, and the ends of the polarizing film on each side are adjusted so that they are located 0.05 mm inside with respect to the ends of the protective film, , a polarizing plate was prepared using a water-based adhesive, and a heat shock test was conducted. As a result, cracks in the polarizing film were not observed.

[Example 2]

The size of the polarizing film is cut so that both the vertical and horizontal widths are 0.1 mm smaller than the size of the protective film, and the ends of the polarizing film on each side are adjusted so that they are located 0.05 mm inside with respect to the ends of the protective film, , A polarizing plate was prepared using a cationic UV-curable adhesive, and a heat shock test was conducted. As a result, cracks in the polarizing film were not observed.

[Example 3]

The size of the polarizing film is cut so that both the vertical and horizontal widths are 0.1 mm smaller than the size of the protective film, and the ends of the polarizing film on each side are adjusted so that they are located 0.05 mm inside with respect to the ends of the protective film, , A polarizing plate was produced using a radical-based ultraviolet curable adhesive, and a heat shock test was conducted. As a result, cracks in the polarizing film were not observed.

[Example 4]

A polarizing plate was prepared in the same manner as in Example 1 except that triacetyl cellulose (Zerotack, thickness: 20 μm, manufactured by Konica Minolta Opto Co., Ltd.) was used for saponifying the protective film, and a heat shock test was conducted. As a result, cracks in the polarizing film were not observed.

[Example 5]

A polarizing plate was prepared in the same manner as in Example 2 except that triacetyl cellulose (Zero Tack, thickness: 20 μm, manufactured by Konica Minolta Opto Co., Ltd.) was used to saponify the protective film, and a heat shock test was performed. As a result, cracks in the polarizing film were not observed.

[Example 6]

A polarizing plate was produced in the same manner as in Example 3, except that triacetyl cellulose (Zerotack, thickness: 20 µm, manufactured by Konica Minolta Opto Co., Ltd.) was used to saponify the protective film, and a heat shock test was conducted. As a result, cracks in the polarizing film were not observed.

[Comparative Example 1]

After cutting both the polarizing film and the protective film into 130 mm × 80 mm, using a water-based adhesive to make a polarizing plate, each side is cut by 5 mm with a super cutter and molded into 120 mm × 70 mm, heat shock test carried out. As a result, cracks occurred at the ends of the polarizing film.

[Comparative Example 2]

Both the polarizing film and the protective film are cut into 130 mm × 80 mm, a polarizing plate is made using cationic UV-curable adhesive, and each side is cut by 5 mm with a super cutter and molded into 120 mm × 70 mm, A heat shock test was conducted. As a result, cracks occurred at the ends of the polarizing film.

[Comparative Example 3]

Both the polarizing film and the protective film are cut into 130 mm × 80 mm, a polarizing plate is made using a radical-based UV curable adhesive, and then each side is cut by 5 mm with a super cutter and molded to 120 mm × 70 mm, A heat shock test was conducted. As a result, many cracks occurred at the end of the polarizing film.

[Comparative Example 4]

The size of the polarizing film is cut so that both the vertical and horizontal widths are 0.1 mm larger than the size of the protective film, and the ends of the polarizing film are adjusted to be 0.05 mm outside of the ends of the protective film on each side, A polarizing plate was produced using a water-based adhesive, and a heat shock test was conducted. As a result, cracks occurred at the ends of the polarizing film.

[Comparative Example 5]

The size of the polarizing film is cut so that both the vertical and horizontal widths are 0.1 mm larger than the size of the protective film, and on each side, the end of the polarizing film is adjusted to be located 0.05 mm outside the end of the protective film, , A polarizing plate was prepared using a cationic UV-curable adhesive, and a heat shock test was conducted. As a result, cracks occurred at the ends of the polarizing film.

[Comparative Example 6]

The size of the polarizing film is cut so that both the vertical and horizontal widths are 0.1 mm larger than the size of the protective film, and on each side, the end of the polarizing film is adjusted to be located 0.05 mm outside the end of the protective film, , A polarizing plate was produced using a radical-based ultraviolet curable adhesive, and a heat shock test was conducted. As a result, many cracks occurred at the end of the polarizing film.

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

DESCRIPTION OF SYMBOLS 1A, 1B, 1C: polarizing plate, 2: polarizing film (polarizer), 2a: end of polarizing film, 3: protective film, 3a: end of protective film, 4: adhesive layer (adhesive), 5: adhesive layer, 6: reflective polarizer (optical function film), 8: liquid crystal cell, 9: liquid crystal panel, 10: liquid crystal display device.

Claims (6)

A polarizer and a protective film laminated on only one side thereof through an adhesive,
The protective film is molded into a predetermined shape,
The protective film is laminated on the entire surface of one side of the polarizer,
The protective film is a cellulose-based resin, a cyclic olefin-based resin, an acrylic resin, or a polyester-based resin,
A polarizing plate in which at least some end portions of the polarizer are located 1 to 500 μm inside the end portion of the protective film,
Further provided with a pressure-sensitive adhesive layer laminated on at least one side of the surface of the polarizer opposite to the side on which the protective film is laminated, and the surface of the protective film on the opposite side to the side on which the polarizer is laminated, ,
In addition, the pressure-sensitive adhesive layer laminated on the surface of the polarizer opposite to the side on which the protective film is laminated, or the pressure-sensitive adhesive layer laminated on the surface of the protective film on the opposite side to the side on which the polarizer is laminated, or both A polarizing plate further comprising an optical function film laminated through all of them, wherein the optical function film is a reflective polarizer. The polarizing plate according to claim 1, wherein all ends of the polarizer are located inside than ends of the protective film. delete delete The polarizing plate according to claim 1, wherein the polarizer has a thickness of 10 μm or less. A liquid crystal display device comprising the polarizing plate according to any one of claims 1, 2 and 5.

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