TW201929281A - Circularly polarizing plate and display device - Google Patents

Abstract

The present invention relates to a circularly polarizing plate l used for a bendable display device including a polarizer 2 and a retardation layer RF disposed on one side of the polarizer 2. A luminosity correction unit transmittance of the polarizer 2 is not less than 42%. The retardation layer RF includes a half wavelength plate 3 and a quarter wavelength plate 4. The half wavelength plate 3 and the quarter wavelength plate 4 each include a layer in which a liquid crystal compound is cured. A slow axis direction of the quarter wavelength plate 4 is in a range of -20 DEG to 20 DEG from an absorption axis direction of the polarizer 2 assuming that a counterclockwise direction is positive, and a bending direction of a display device is set in a range of 80 DEG to 100 DEG or -10 DEG to 10 DEG with respect to the slow axis direction of the quarter wavelength plate 4.

Description

 Circular polarizing plate and display device  

The present invention relates to a circularly polarizing plate. Furthermore, it relates to a flexible display device having the above-described circular polarizing plate.

The priority is claimed on the basis of Japanese Patent Application No. 2017-217106, which was filed in Japan on November 10, 2017, and Japanese Patent Application No. 2018-201205, which was filed in Japan on October 25, 2018, and is hereby incorporated by reference. content.

Conventionally, in order to suppress an adverse effect caused by reflection of external light in a display device, a circularly polarizing plate is used. On the other hand, in recent years, the demand for a bendable (flexible) display device typified by an organic electroluminescence (EL) display device has become stronger. Further, not only is the flexibility of the display device required, but also the flexibility at a very small radius of curvature is required.

However, if the organic EL display device is bent with a very small radius of curvature, a large force is applied to the phase difference layer in the circularly polarizing plate (the tensile force is outside the curved portion, and the inner side of the curved portion is The compressive force) has a problem that the phase difference of the bent portion changes.

Therefore, in order to solve such a problem, Patent Document 1 below proposes a circularly polarizing plate having a retardation film including a 1/2 wavelength (λ/2) plate and a 1/4 wavelength (λ/4) plate, λ/2. Each of the plate and the λ/4 plate system includes a liquid crystal compound, and is adjusted so that the slow axis direction of the retardation film is set at an angle of 75 to 105 degrees with respect to the bending direction of the display device.

 [Previous Technical Literature]    [Patent Literature]  

Patent Document 1: International Publication No. 2016/158300

However, in the case of the above-mentioned bendable display device, the visibility is further improved. Furthermore, it is required to reduce the hue (hue) change of the reflected light in the curved portion when the display device is bent.

Therefore, a circularly polarizing plate suitable for use in a flexible display device must be able to follow the curved portion of the display device. Furthermore, it is also required that wrinkles are not easily generated before and after the bending of the circularly polarizing plate.

The present invention has been made in view of such a prior art, and an object thereof is to provide a circular polarizing plate and a flexible display device having the above-described circular polarizing plate, which reduces color change caused by bending, and does not It is easy to produce wrinkles caused by bending.

In view of the means for solving the above problems, according to an aspect of the present invention, a circular polarizing plate can be provided for use in a flexible display device, the circular polarizing plate comprising: a polarizing member, and one of the polarizing members a phase difference layer disposed on the side; wherein the polarizing element has a visual sensitivity correcting monomer transmittance of 42% or more, and the phase difference layer includes a 1⁄2 wavelength plate and a 1⁄4 wavelength plate, and the 1⁄2 wavelength plate And the 1/4 wavelength plate respectively includes a layer obtained by curing the liquid crystal compound; when the counterclockwise direction is positive, the slow axis direction of the 1/4 wavelength plate is counted from the absorption axis direction of the polarizer The range of -20° to 20°, and the bending direction of the aforementioned display device is set in the range of 80° to 100° or −10° to 10° with respect to the slow axis direction of the aforementioned quarter wave plate.

Further, in the above circular polarizing plate, the 1/2 wavelength plate and the 1/4 wavelength plate may be connected via an adhesive layer.

Further, in the above circular polarizing plate, the display device may be an organic electroluminescence display device.

Further, in the above circular polarizing plate, the configuration may be such that the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinate without crossing the a* coordinate axis and the b* coordinate axis.

Furthermore, according to an aspect of the present invention, a flexible display device comprising any of the above-described circular polarizing plates and a flexible display panel can be provided.

Further, in the display device, the touch sensor may be disposed on a side of the circular polarizing plate facing the display panel, and a side of the circular polarizing plate facing the display panel The window film is configured on the opposite side.

Further, in the display device described above, the touch sensor may be provided on a side of the circular polarizing plate opposite to the side facing the display panel.

That is, the present invention has the following aspects.

[1] A circularly polarizing plate for use in a flexible display device, the circular polarizing plate comprising: a polarizing member; and a phase difference layer disposed on one side of the polarizing member; wherein the illuminance of the polarizing member The correction monomer transmittance is 42% or more; the retardation layer includes a 1⁄2 wavelength plate and a 1⁄4 wavelength plate; and the 1⁄2 wavelength plate and the 1⁄4 wavelength plate are respectively cured by a liquid crystal compound. When the counterclockwise direction is set to be positive, the slow axis direction of the 1/4 wavelength plate is in the range of -20° to 20° from the absorption axis direction of the polarizer; and, relative to the above 1 The slow axis direction of the /4 wavelength plate, the bending direction of the aforementioned display device is set in the range of 80 to 100 or -10 to 10 .

[2] The circularly polarizing plate according to [1], wherein the 1/2 wavelength plate and the 1/4 wavelength plate are followed by an adhesive layer.

[3] The circularly polarizing plate according to [1] or [2] wherein the display device is an organic electroluminescence display device.

[4] The circularly polarizing plate according to any one of [1] to [3] wherein the hue of the reflected light obtained before and after the bending has a sign in the a*b* chromaticity coordinate that does not cross the a* coordinate axis and The b* coordinate axis changes.

[5] A flexible display device comprising: the circularly polarizing plate according to any one of [1] to [4], and a flexible display panel.

[6] The flexible display device according to [5], comprising: a touch sensor disposed on a side of the circular polarizing plate facing the display panel; and a front surface facing the circular polarizing plate The side of the display panel is the window film disposed on the opposite side.

[7] The flexible display device according to [5], wherein the touch sensor is disposed on a side of the circular polarizing plate opposite to a side facing the display panel.

As described above, according to an aspect of the present invention, it is possible to provide a circular polarizing plate and a flexible display device having the above-described circular polarizing plate, which reduces the color change caused by bending and is less likely to be generated by Wrinkles caused by bending.

1‧‧‧Polar polarizer

2‧‧‧ polarizer

3‧‧‧λ/2 board (1/2 wavelength board)

4‧‧‧λ/4 board (1/4 wavelength board)

5, 6‧‧‧ protective film (protective layer)

7‧‧‧PSA layer (adhesive layer)

8‧‧‧Adhesive layer or adhesive layer

9‧‧‧PSA layer (adhesive layer)

10‧‧‧ display device

20‧‧‧ display panel

30‧‧‧Display device

40‧‧‧Touch sensor

50‧‧‧ window film

200‧‧‧Organic EL components

210‧‧‧Substrate

220‧‧‧1st electrode

230‧‧‧Organic EL layer

240‧‧‧2nd electrode

250‧‧‧ sealing layer

RF‧‧‧ phase difference layer

Fig. 1 is a cross-sectional view showing the configuration of a circularly polarizing plate according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing the configuration of a flexible display device having a circularly polarizing plate shown in Fig. 1.

Fig. 3 is a cross-sectional view showing the configuration of an organic EL element.

Fig. 4A is a schematic view for explaining a bending state of the display device.

Fig. 4B is a schematic view for explaining a curved state of the display device.

Fig. 4C is a schematic view for explaining a bending state of the display device.

Fig. 4D is a schematic view for explaining a bending state of the display device.

Fig. 5 is a schematic view for explaining the relationship between the bending direction of the display device and the absorption axis direction of the polarizer, and the relationship between the slow axis direction of the λ/2 plate and the slow axis direction of the λ/4 plate.

Fig. 6 is a cross-sectional view showing another configuration example of a flexible display device having a circularly polarizing plate shown in Fig. 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Further, in the drawings used in the following description, in order to facilitate the viewing of the respective constituent elements, the constituent elements are schematically displayed, and the size scale may be changed depending on the constituent elements. In addition, the materials and the numerical values of the following descriptions are not limited to the scope of the invention, and the present invention is not limited thereto, and may be appropriately modified and implemented without departing from the spirit and scope of the invention.

In one embodiment of the present invention, for example, the circular polarizing plate 1 shown in Fig. 1 and the flexible display device 10 having the circular polarizing plate 1 shown in Fig. 2 will be described. In addition, FIG. 1 is a cross-sectional view showing the configuration of the circularly polarizing plate 1. Fig. 2 is a cross-sectional view showing the configuration of the display device 10.

As shown in Fig. 1, the circularly polarizing plate 1 of the present embodiment includes a polarizer 2, a retardation layer RF disposed on one surface side of the polarizer 2, and the retardation layer RF includes 1/2 wavelength (λ/2). Plate 3 and 1/4 wavelength (λ/4) plate 4. Further, protective films (protective layers) 5 and 6 are disposed on both surfaces of the polarizer 2, respectively.

On one surface side of the polarizer 2, a λ/2 plate 3 is laminated via a PSA layer (adhesive layer) 7. The λ/2 plate 3 and the λ/4 plate 4 are laminated via an adhesive layer or an adhesive layer 8. On the surface of the circularly polarizing plate 1 facing the λ/4 plate 4, a PSA layer (adhesive layer) 9 for laminating a display panel 20 to be described later is disposed. Further, on the surface of the PSA layer 9, a release film (not shown) is attached before use. Further, the PSA layers 7, 9 are formed, for example, of an acrylic adhesive.

The polarizer 2 is a light-transmitting light that has a linearly polarized light having a polarizing surface in a specific direction, and the light passing through the polarizer 2 is a linearly polarized light that vibrates in the transmission axis direction of the polarizer. The thickness of the polarizer 2 is, for example, about 1 μm to 80 μm.

In the polarizing member 2, for example, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partial saponified film may be used, and iodine or two may be used. For the dyeing treatment and the stretching treatment by a dichroic material such as a coloring dye, for example, a polyene-based alignment film such as a dehydrated material of polyvinyl alcohol or a dehydrochloric acid-treated product of polyvinyl chloride may be used. Among them, those having excellent optical properties are preferably obtained by dyeing a polyvinyl alcohol-based film with iodine and performing uniaxial stretching.

Dyeing with iodine can be carried out, for example, by immersing a polyvinyl alcohol-based film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably from 3 to 7 times. The stretching can be carried out after the dyeing treatment, or can be carried out while dyeing. Furthermore, it is also possible to perform dyeing after stretching.

The polyvinyl alcohol-based film can be subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, or the like as needed. For example, by immersing the polyvinyl alcohol-based film in water and washing it with water before dyeing, it is possible to wash not only the surface of the polyvinyl alcohol-based film or the anti-blocking agent but also the polyvinyl alcohol. The mesangial swelling causes uneven dyeing and the like.

For the polarizing element 2, for example, a dichroic dye can be used in a cured film in which a liquid crystal compound is polymerized as described in JP-A-2016-170368. As the dichroic dye, an absorber having a wavelength in the range of 380 to 800 nm can be used, and an organic dye is preferably used. The dichroic dye may, for example, be an azo compound. The liquid crystal compound is a liquid crystal compound which can be directly polymerized after the alignment, and which has a polymerizable group in the molecule.

The degree of visual sensitivity correction of the polarizing member 2 is preferably 95% or more, and more preferably 97% or more. Further, it may be 99% or more, or may be 99.9% or more. The illuminance correcting polarization of the polarizer 2 can be 99.995% or less, or 99.99% or less. For the sensitization degree correction, the absorbance photometer ("V7100" manufactured by JASCO Corporation) can be used for the degree of polarization obtained and the 2 degree field of view (JIS Z 8701:1999) is used. The light source is calculated by performing visual sensitivity correction.

By setting the illuminance correcting polarization of the polarizer 2 to 95 to 99.9%, it is easy to adjust the initial (pre-bending) hue to a position deviating from the neutral. Accordingly, the hue of the reflected light before and after the bending described later in the a*b* chromaticity coordinates does not easily change across the a* coordinate axis and the b* coordinate axis. In addition, the durability of the circularly polarizing plate 1 can be improved by setting the viewing sensitivity correction polarization of the polarizer 2 to 99.9% or more. On the other hand, when the illuminance correcting polarization of the polarizer 2 is less than 95%, the function as an antireflection film may not be exhibited. In other words, when the illuminance correcting polarization of the polarizer 2 is 95% or more, the function as an antireflection film can be easily exhibited.

The transmittance of the polarizing member 2 is preferably 42% or more, more preferably 44% or more, more preferably 60% or less, still more preferably 50% or less. For the sensibility correction of the monomer transmittance, an absorbance photometer ("V7100" manufactured by JASCO Corporation) equipped with an integrating sphere can be used, and the obtained transmittance is based on the 2 degree field of view of JIS Z 8701:1999 ( C light source) is calculated by performing visual sensitivity correction. The lower limit value and the upper limit value described above can be arbitrarily combined. The combination example is 42% or more and 60% or less, and 44% or more and 50% or less.

By setting the illuminance correcting unit transmittance of the polarizer 2 to 42% or more, the eccentric hue of the polarizer 2 can be easily adjusted to a position deviating from the neutral side, and thus the color change before and after the bending described later can be performed. Not obvious. On the other hand, when it exceeds 50%, the degree of polarization becomes too low, and there is a case where the function of antireflection cannot be achieved. That is, when it is 50% or less, the degree of polarization does not become too low, and it becomes easy to achieve the function of antireflection.

The λ/2 plate 3 is a function of giving a phase difference of π (= λ/2) in the direction of the electric field vibration (polarizing surface) of the incident light, and has a function of changing the direction (polarization direction) of the linearly polarized light. Further, when the light of the circularly polarized light is incident, the direction of rotation of the circularly polarized light can be reversed.

The Re(λ) of the in-plane retardation value of the λ/2 plate 3 at a specific wavelength λ nm satisfies Re(λ)=λ/2. This formula can be achieved at any wavelength (for example, 550 nm) in the visible light region. Among them, Re (550) having a retardation value at a wavelength of 550 nm satisfies 210 nm ≦ Re (550) ≦ 300 nm. Furthermore, it is more preferable to satisfy 220 nm ≦Re (550) ≦ 290 nm.

The Rth (550) of the retardation value in the thickness direction of the λ/2 plate 3 measured at a wavelength of 550 nm is preferably -150 to 150 nm, more preferably -100 to 100 nm.

The thickness of the λ/2 plate 3 is not particularly limited, but from the viewpoint of easily exhibiting the effect of preventing wrinkles, it is preferably 0.5 to 10 μm, more preferably 0.5 to 5 μm , and 0.5. It is even better to 3 μ m. Further, regarding the thickness of the λ/2 plate 3, the thickness of any five points in the plane is measured and these are arithmetically averaged.

The λ/2 plate 3 may include a film made of a resin exemplified as a material of the protective films 5 and 6 to be described later, a layer obtained by curing a liquid crystal compound, and the like. When the λ/2 plate 3 is formed of a resin, among them, a polycarbonate resin, a cyclic olefin resin, a styrene resin, or a cellulose resin is preferable. In the present embodiment, the λ/2 plate 3 preferably contains a layer obtained by curing a liquid crystal compound. The type of the liquid crystal compound is not particularly limited, and can be classified into a rod-shaped (rod-like liquid crystal compound) and a disk-shaped type (a discotic liquid crystal compound or a discotic liquid crystal compound) from the shape thereof. Furthermore, each has a low molecular type and a high molecular type. In addition, the term "polymer" generally refers to a degree of polymerization of 100 or more (polymer physics ‧ phase transfer kinetics, Doi Masato, 2 pages, Iwanami Shoten, 1992).

In the present embodiment, any liquid crystal compound can also be used. Further, two or more kinds of rod-like liquid crystal compounds, two or more kinds of discotic liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a discotic liquid crystal compound may be used.

In addition, the rod-like liquid crystal compound is preferably used in, for example, the first item of the Japanese Patent Application Laid-Open No. Hei 11-513019, or the paragraphs [0026] to [0098] of JP-A-2005-289980. The discotic liquid crystal compound is preferably used in, for example, paragraphs [0020] to [0067] of JP-A-2007-108732, or paragraphs [0013] to [0108] of JP-A-2010-244038. By.

The λ/2 plate 3 is more preferably formed by using a liquid crystal compound (a rod-like liquid crystal compound or a discotic liquid crystal compound) having a polymerizable group. Thereby, the change in the optical characteristics due to temperature and the change due to humidity can be reduced.

The liquid crystal compound may be a mixture of two or more kinds. In this case, it is preferred that at least one of them has two or more polymerizable groups. In other words, the λ/2 plate 3 is preferably a layer in which a rod-like liquid crystal compound having a polymerizable group or a discotic liquid crystal compound having a polymerizable group is fixed by polymerization, and such a layer is included in the liquid crystal compound. Hardened layer. At this time, it is not necessary to display liquid crystallinity after being a layer.

The type of the polymerizable group contained in the rod-like liquid crystal compound or the discotic liquid crystal compound is not particularly limited, and for example, a functional group capable of undergoing addition polymerization such as a polymerizable ethylenically unsaturated group or a cyclopolymerizable group is preferable. base. More specifically, for example, a (meth) acrylonitrile group, a vinyl group, a styryl group, an allyl group or the like can be mentioned. Among them, a (meth) acrylonitrile group is preferred. Further, the (meth) acrylonitrile group means a concept including both a methacryl fluorenyl group and an acryl fluorenyl group.

The method of forming the λ/2 plate 3 is not particularly limited, and a known method can be mentioned. For example, a composition for forming an optical anisotropic layer (hereinafter simply referred to as "composition") containing a liquid crystal compound having a polymerizable group can be applied to a predetermined substrate (including a temporary substrate) to form a coating film, and the resulting film can be obtained. The coating film is subjected to a curing treatment (irradiation of ultraviolet rays (light irradiation treatment) or heat treatment), whereby the λ/2 plate 3 is produced.

The coating of the composition can be carried out by a known method such as a bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method. And implementation.

The composition may contain components other than the above liquid crystal compound. For example, a polymerization initiator may also be contained in the composition. The polymerization initiator to be used is selected, for example, as a thermal polymerization initiator or a photopolymerization initiator depending on the form of the polymerization reaction. For example, the photopolymerization initiator may, for example, be an α-carbonyl compound, an alcohol ketone ether (Acyloin ether), an α-hydrocarbon-substituted aromatic alcohol ketone compound, a polynuclear ruthenium compound, a triaryl imidazole dimer, and a p-aminobenzene. Combination of ketones and the like. The polymerization initiator is preferably used in an amount of from 0.01 to 20% by mass, more preferably from 0.5 to 5% by mass, based on the total solids of the composition.

Further, from the viewpoint of the uniformity of the coating film and the strength of the film, a polymerizable monomer may be contained in the composition. The polymerizable monomer may be a compound having a radical polymerizable property or a cationic polymerizable property. Among them, a polyfunctional radical polymerizable monomer is preferred.

Further, the polymerizable monomer is preferably one having copolymerization with the above-mentioned liquid crystal compound containing a polymerizable group. Specific examples of the polymerizable monomer include those described in paragraphs [0018] to [0020] of JP-A-2002-296423. The amount of the polymerizable monomer to be used is preferably from 1 to 50% by mass, more preferably from 2 to 30% by mass, based on the total mass of the liquid crystal compound.

Further, a surfactant may be contained in the composition from the viewpoint of uniformity of the coating film and film strength. The surfactant can be exemplified by a conventionally known compound. Among them, a fluorine compound is particularly preferred. Specific examples of the surfactants include the compounds described in paragraphs [0028] to [0056] of JP-A-2001-330725, and paragraphs [0069] to [0126] in the specification of Japanese Patent Application No. 2003-295212. The compound described.

Further, a solvent may be contained in the composition, and an organic solvent is preferably used. The organic solvent may, for example, be a guanamine (for example, N,N-dimethylformamide), an anthracene (for example, dimethyl fluorene), a heterocyclic compound (for example, pyridine), a hydrocarbon (for example, benzene or hexane), or Alkyl halides (such as chloroform, dichloromethane), esters (such as methyl acetate, ethyl acetate, butyl acetate), ketones (such as acetone, methyl ethyl ketone), ethers (such as tetrahydrofuran, 1,2- Dimethoxyethane). Among them, an alkyl halide or a ketone is preferred. Further, two or more organic solvents may be used in combination.

Further, the composition may further include a vertical alignment promoter such as a polarizing member interface side vertical alignment agent and an air interface side vertical alignment agent, and a horizontal alignment promoter such as a polarizer interface side horizontal alignment agent and an air interface side horizontal alignment agent. Various kinds of alignment agents. Further, the composition may contain a adhesion improving agent, a plasticizer, a polymer or the like in addition to the above components.

The λ/2 plate 3 may also include an alignment film having a function of defining an alignment direction of the liquid crystal compound. The alignment film generally has a polymer as a main component. Polymer materials for alignment films are described in most documents, and many commercial products can be used. Among them, as the polymer material, polyvinyl alcohol or polyimine, a derivative thereof is preferably used, and it is particularly preferred to use a modified or unmodified polyvinyl alcohol.

For the alignment film which can be used in the present embodiment, reference is made to International Publication No. 2001/88574, page 43, line 24 to page 49, line 8, Japanese Patent No. 3907735, [0071] to [0095] The modified polyvinyl alcohol described in the paragraph.

Further, a generally known alignment treatment can be performed for the alignment film. For example, a rubbing treatment or a light alignment treatment for irradiating a polarized light is preferable, and from the viewpoint of the surface roughness of the alignment film, a photoalignment treatment is preferred.

The thickness of the alignment film is not particularly limited, and is usually 20 μm or less, and preferably 0.01 to 10 μm, more preferably 0.01 to 5 μm, still more preferably 0.01 to 1 μm.

The λ/4 plate 4 is a phase difference of π/2 (= λ / 4) given to the direction of the electric field vibration (polarizing surface) of the incident light, and has a linearly polarized light of a specific wavelength converted into a circularly polarized light (or a circularly polarized light is converted) The function of linear polarization).

The Re(λ) of the in-plane retardation value of the λ/4 plate 4 at a specific wavelength λ nm satisfies Re(λ)=λ/4. This formula can be achieved at any wavelength (for example, 550 nm) in the visible light region. Among them, Re (550) having a retardation value at a wavelength of 550 nm satisfies 100 nm ≦ Re (550) ≦ 160 nm. Further, it is more preferable to satisfy 110 nm ≦Re (550) ≦ 150 nm.

The Rth (550) of the retardation value in the thickness direction of the λ/4 plate 4 measured at a wavelength of 550 nm is preferably -120 to 120 nm, more preferably -80 to 80 nm.

The thickness of the λ/4 plate 4 is not particularly limited, but is preferably 0.5 to 10 μm, more preferably 0.5, from the viewpoint of preventing wrinkles due to the difference in dimensional change between the front surface and the back surface of the film during bending. Up to 5 μm, more preferably 0.5 to 3 μm. Further, regarding the thickness of the λ/4 plate 4, the thickness of any five points in the plane is measured and these are arithmetically averaged.

The λ/4 plate 4 preferably contains a layer obtained by hardening a liquid crystal compound. The type of the liquid crystal compound is not particularly limited, and the same materials as those exemplified as the material of the above λ/2 plate 3 can be used. Among them, a layer formed by fixing a rod-like liquid crystal compound having a polymerizable group or a discotic liquid crystal compound having a polymerizable group by polymerization is preferred. At this time, it is not necessary to display liquid crystallinity after being a layer.

In the layer included in the circularly polarizing plate 1, in addition to the polarizer 2, the layer obtained by curing the liquid crystal compound is preferably one layer or two layers. In addition to the polarizer 2, when three or more layers of the liquid crystal compound are hardened, since the number of layers in which wrinkles may occur is increased, it is presumed that wrinkles are likely to occur at the time of bending.

The protective films 5 and 6 function as a protective layer for protecting the polarizer 2, and the protective film 5 is disposed at least on the outer surface of the polarizer 2 (the surface opposite to the side facing the λ/2 plate 3). Further, the protective film 6 may be disposed on the inner surface of the polarizer 2 (the surface facing the side of the λ/2 plate 3).

As the material of the protective films 5 and 6, for example, a thermoplastic resin having light transmissivity (preferably optically transparent), for example, a chain polyolefin resin (polypropylene resin or the like), a ring shape can be used. A polyolefin resin such as a polyolefin resin (such as a decene-based resin), such as a cellulose ester resin such as cellulose triacetate or cellulose diacetate, a polyester resin or a polycarbonate resin. (Meth)acrylic resin, polystyrene resin, or a mixture or copolymer of these. That is, the λ/2 plate 3 can also function as the protective films 5 and 6.

Further, the protective films 5 and 6 may be protective films having an optical function such as a retardation film or a brightness enhancement film. For example, a retardation film to which an arbitrary retardation value is imparted can be formed by stretching a film containing the thermoplastic resin (uniaxial stretching or biaxial stretching or the like) or forming a liquid crystal layer or the like on the film.

In the chain-like polyolefin resin, for example, a homopolymer of a chain olefin such as a polyethylene resin or a polypropylene resin may be used, and a copolymer containing two or more kinds of chain olefins may also be mentioned.

The cyclic polyolefin resin is a general term for a resin obtained by polymerizing a cyclic olefin as a polymerization unit. Specific examples of the cyclic polyolefin-based resin include a ring-opened (co)polymer of a cyclic olefin, an addition polymer of a cyclic olefin, and a copolymer of a cyclic olefin and a chain olefin such as ethylene or propylene ( Representative examples are random copolymers, and graft polymers obtained by modifying such unsaturated carboxylic acids or derivatives thereof, and such hydrides. Among them, the cyclic olefin is preferably a decene-based resin obtained by using a norbornene-based monomer such as a norbornene or a polycyclic norbornene-based monomer.

The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Further, the copolymer may be used, or one of the hydroxyl groups may be modified with another substituent. Among them, cellulose triacetate (i.e., cellulose triacetate, TAC) is particularly preferred.

The polyester-based resin is a resin other than the cellulose ester-based resin having an ester bond, and is generally composed of a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalate. A diol may be used for the polyhydric alcohol, and examples thereof include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, and cyclohexane dimethanol.

Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and polybutylene terephthalate. Propylene glycol, propylene naphthalate, dimethyl dimethyl terephthalate, cyclohexane dimethyl phthalate.

The polycarbonate resin includes a polymer in which a monomer unit is bonded via a carbonate group. The polycarbonate resin may be, for example, a resin called a modified polycarbonate in which a polymer skeleton is modified, or a copolymerized polycarbonate or the like.

The (meth)acrylic resin is a resin having a compound having a (meth)acryl fluorenyl group as a main constituent monomer. Specific examples of the (meth)acrylic resin include, for example, poly(meth)acrylate such as polymethyl methacrylate, methyl methacrylate-(meth)acrylic acid copolymer, and methyl methacrylate- (Meth)acrylate copolymer, methyl methacrylate-acrylate-(meth)acrylic acid copolymer, methyl (meth)acrylate-styrene copolymer (MS resin, etc.), methyl methacrylate and A copolymer of a compound having an alicyclic hydrocarbon group (e.g., methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-methyl (meth) acrylate), and the like. It is preferred to use a polymer containing a poly(meth)acrylic acid C _1-6 (carbon number 1 to 6) alkyl ester such as poly(methyl) acrylate as a main component. More preferably, a methyl methacrylate-based resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

The thickness of the protective films 5, 6 is preferably from 10 μm to 200 μm, more preferably from 10 μm to 100 μm, still more preferably from 15 μm to 95 μm. The protective film 5, 6 has an in-plane retardation value Re (550) of, for example, 0 nm to 10 nm, and a phase difference Rth (550) in the thickness direction thereof is, for example, -80 nm to +80 nm.

As for the outer protective film 5, on the surface opposite to the side opposite to the polarizing member 2, hard coat treatment, anti-reflection treatment, anti-adhesive treatment, anti-glare treatment, etc. may be performed as needed. Surface treatment. The thickness of the protective film 5 at this time is 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, still more preferably 5 μm to 150 μm.

The inner protective film 6 is preferably optically isotropic. That is, the term "optical isotropic" means that the in-plane phase difference value Re (550) is 0 nm to 10 nm, and the thickness direction phase difference value Rth (550) is -10 nm to +10 nm. The thickness of the protective film 6 at this time is preferably from 20 μm to 200 μm, more preferably from 30 μm to 100 μm, still more preferably from 35 μm to 95 μm.

In the adhesive layer 8, as the adhesive, for example, an active energy ray-curable adhesive containing a curable compound which is hardened by irradiation with an active energy ray such as ultraviolet rays, visible light, electron rays, or X-rays can be used. (preferably an ultraviolet curable adhesive) or a water-based adhesive obtained by dissolving or dispersing an adhesive component such as a polyvinyl alcohol-based resin in water. In the circularly polarizing plate 1, the λ/2 plate 3 and the λ/4 plate 4 can be laminated via the adhesive layer 8, thereby preventing wrinkles from occurring during bending.

From the viewpoint of exhibiting good adhesion, the active energy ray-curable adhesive is preferably an active energy ray-curable adhesive which can use a cationically polymerizable curable compound and/or a radically polymerizable curable compound. Composition. The active energy ray-curable adhesive may further comprise a cationic polymerization initiator and/or a radical polymerization initiator for causing the curable compound to start a curing reaction.

Examples of the cationically polymerizable curable compound include an epoxy compound (a compound having one or two or more epoxy groups in the molecule) and an oxetane compound (one in the molecule). Or a compound of two or more oxetane rings), or a combination thereof. Examples of the radically polymerizable curable compound include a (meth)acrylic compound (a compound having one or two or more (meth)acryloxy groups in the molecule) and a radical polymerizable double bond. Other vinyl compounds, or combinations of these. A cationically polymerizable curable compound and a radically polymerizable curable compound may also be used in combination.

In the active energy ray-curable adhesive, a cationic polymerization accelerator, an ion trapping agent, an antioxidant, a chain transfer agent, an adhesion-imparting agent, a thermoplastic resin, a filler, and a flow regulator may be contained as needed. Additives such as plasticizers, defoamers, antistatic agents, leveling agents, solvents, etc.

When the λ/2 plate 3 and the λ/4 plate 4 are bonded together using an active energy ray-curable adhesive, the λ/2 plate 3 and λ/ are laminated by an active energy ray-curable adhesive as the adhesive layer 8. After 4 sheets 4, an active energy ray such as ultraviolet rays, visible light, electron rays, or X-rays is irradiated to harden the adhesive layer. Among them, ultraviolet light is preferred, and a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, or the like can be used as the light source. When a water-based adhesive is used, the λ/2 plate 3 and the λ/4 plate 4 may be laminated by a water-based adhesive, and then dried by heating.

The thickness of the subsequent agent layer 8 is preferably from 0.5 to 5 μm, more preferably from 0.5 to 3 μm.

The storage elastic modulus of the subsequent agent layer 8 at a temperature of 30 ° C is preferably from 600 MPa to 4,000 MPa, more preferably from 700 MPa to 3,500 MPa, still more preferably from 1,000 MPa to 3,000 MPa, most preferably from 1,500 MPa to 3,000 MPa. When the λ/2 plate 3 and the λ/4 plate 4 are bonded to each other by the hard adhesive layer 8 which exhibits such a storage elastic modulus, it is possible to more easily prevent wrinkles from occurring in the retardation layer at the time of bending.

Regarding the storage elastic modulus of the adhesive layer 8 at a temperature of 30 ° C, if the storage elastic modulus of the adhesive layer 8 in the circularly polarizing plate 1 at a temperature of 30 ° C can be directly measured by the following method, the measurement is made. value. On the other hand, if it is not possible to directly measure, it is possible to form an adhesive layer test piece on the release paper according to the same conditions (the type of the adhesive agent and the curing condition) as in the case of forming the adhesive layer 8, and the adhesive layer test is performed. After the sheet was peeled off from the release paper, the same value as the storage elastic modulus was measured by the following method.

The storage elastic modulus of the subsequent layer 8 or the subsequent layer test piece can be measured by a commercially available dynamic viscoelastic device, and can be measured, for example, by the product name DVA-220 manufactured by IT Measurement and Control Co., Ltd.

The adhesive layer 8 is preferably selected from a conventionally known one as an adhesive, and is an adhesive having a degree that the polarizing plate is exposed to a high-temperature environment, a hot and humid environment, or a high-temperature and low-temperature environment without peeling off. can. Specifically, an acrylic adhesive, a polyoxynoxy adhesive, a rubber adhesive, etc. are mentioned, and an acrylic adhesive is especially preferable in terms of transparency, weather resistance, heat resistance, and workability. .

Adhesives, plasticizers, fillers including glass fibers, glass beads, metal powders, other inorganic powders, pigments, colorants, fillers, antioxidants, ultraviolet absorption, etc., may be appropriately formulated as needed in the adhesive. Various additives such as an agent, an antistatic agent, and a decane coupling agent.

The adhesive layer 8 is usually formed by applying a solution of an adhesive to a release sheet and drying it. When applied to a release sheet, a roll coating method such as reverse coating or gravure coating may be employed; a spin coating method, a screen coating method, a fountain coating method, and dipping Method, spray method, etc. The release sheet provided with the adhesive layer can be a method of transferring the adhesive or the like.

The thickness of the adhesive layer 8 is usually from about 3 to 100 μm , preferably from 5 to 50 μm .

The circularly polarizing plate 1 of the present embodiment can be used for the flexible display device 10 as shown in Fig. 2. Specific examples of the flexible display device 10 include an organic EL display device, a liquid crystal display device using circularly polarized light (a representative liquid crystal display device of a VA (Vertical Alignment) mode), and a MEMS (Micro Electro Mechanical Systems). Display, etc. Among them, the circularly polarizing plate 1 of the present embodiment is particularly suitable for a flexible organic EL display device.

Specifically, as shown in FIG. 2, the display device 10 of the present embodiment includes a flexible display panel 20 and the above-described circular polarizing plate 1 disposed on the viewing side of the display panel 20. The circularly polarizing plate 1 is attached to the surface on the viewing side of the display panel 20 via the PSA layer 9 so that the polarizer 2 becomes the viewing side.

In the display device 10 of the present embodiment, the light passing through the polarizer 2 is linearly polarized by causing external light to enter from the viewing side of the display panel 20. This linearly polarized light is circularly polarized by the λ/4 plate 4 after changing the direction of the linearly polarized light by the λ/2 plate 3. The circularly polarized light is reflected by the display panel 20 to become a circularly polarized light that is inverted when incident. The circularly polarized light reflected by the display panel 20 is a linearly polarized light that is orthogonal to the incident when it passes through the λ/4 plate 4 and the λ/2 plate 3 again. Therefore, the linearly polarized light is blocked by the polarizer 2. As a result, the influence caused by the reflection of the external light can be suppressed.

As an example of the display panel 20, for example, the organic EL element 200 shown in Fig. 3 is included. In addition, FIG. 3 is a cross-sectional view showing the configuration of the organic EL element 200.

Specifically, the organic EL element 200 includes a substrate 210, a first electrode 220, an organic EL layer 230, a second electrode 240, and a sealing layer 250 covering the same. Further, the organic EL element 200 may be provided with a planarization layer (not shown) on the substrate 210, for example, or an insulating layer for preventing a short circuit between the first electrode 220 and the second electrode 240 ( Not shown).

The substrate 210 is made of a material having flexibility. When the flexible substrate 210 is used, the display device 10 can be bent at the above-described radius of curvature. Further, since the organic EL element 200 can be manufactured using a so-called roll-to-roll process, low cost and mass production can be achieved. Furthermore, the substrate 210 is preferably made of a material having barrier properties. Such a substrate 210 can protect the organic EL layer 230 from oxygen or moisture.

Specific materials of the barrier substrate and the flexible substrate 210 include, for example, a thin glass to which flexibility is imparted, a thermoplastic resin or a thermosetting resin film to which barrier properties are imparted, an alloy, a metal, or the like.

Examples of the thermoplastic resin or the thermosetting resin include a polyester resin, a polyimide resin, an epoxy resin, a polyurethane resin, a polystyrene resin, and a polyolefin resin. A polyamide resin, a polycarbonate resin, a silicone resin, a fluorine resin, or an acrylonitrile-butadiene-styrene copolymer resin. Examples of the alloy include stainless steel, 36 alloy, and 42 alloy. Examples of the metal include copper, nickel, iron, aluminum, and titanium.

The thickness of the substrate 210 is preferably from 5 μm to 500 μm, more preferably from 5 μm to 300 μm, still more preferably from 10 μm to 200 μm. If it is such a thickness, the display device 10 can be bent at the above-described radius of curvature. Furthermore, the organic EL element 200 can be applied to a roll-to-roll process.

The first electrode 220 can function as an anode. In this case, the material constituting the first electrode is preferably a material having a large work function from the viewpoint of easily achieving hole injection properties. Specific examples of such a material include indium tin oxide (ITO), indium zinc oxide (IZO), indium tin oxide added with antimony oxide (ITSO), indium oxide containing tungsten oxide (IWO), and oxidation containing tungsten oxide. Transparent conductive materials such as indium zinc (IWZO), indium oxide containing titanium oxide (ITiO), indium tin oxide containing titanium oxide (ITTiO), indium tin oxide containing molybdenum (ITMO), and metals such as gold, silver, and platinum And these alloys.

The organic EL layer 230 is a laminate including various organic thin films. Specifically, the organic EL layer 230 has a hole injection layer 230a which is composed of a hole injecting organic material (for example, a triphenylamine derivative) and which is provided for improving the hole injection efficiency from the anode; a hole transport layer 230b composed of copper phthalocyanine; a luminescent organic substance (for example, fluorene, bis[N-(1-naphthyl)-N-phenyl]benzidine, N,N'-diphenyl-NN a light-emitting layer 230c composed of bis(1-naphthyl)-1,1'-(biphenyl)-4,4'-diamine (NPB); for example, an 8-hydroxyquinoline aluminum complex The electron transport layer 230d is composed of an electron injecting layer 230d composed of an electron injecting material (for example, an anthracene derivative or lithium fluoride), and is provided to enhance electron injection efficiency from the cathode.

In addition, the organic EL layer 230 may be any suitable combination that allows electrons in the light-emitting layer 230c to be recombined with holes to generate light. The thickness of the organic EL layer 230 is preferably as thin as possible so as to penetrate light as much as possible, specifically, 5 nm to 200 nm, preferably about 10 nm.

The second electrode 240 functions as a cathode. In this case, the material constituting the second electrode 240 is preferably a material having a small work function from the viewpoint of facilitating electron injection and improving luminous efficiency. Specific examples of such a material include aluminum, magnesium, and the like.

The sealing layer 250 is composed of a material excellent in barrier properties and transparency. Examples of the material constituting the sealing layer 250 include an epoxy resin, a polyurea, and the like. Further, the sealing layer 250 can be formed by coating an epoxy resin (epoxy resin adhesive) and attaching a barrier sheet thereon.

The organic EL element 200 can be continuously manufactured by a roll-to-roll process. The organic EL element 200 can be manufactured by a process based on the order described in, for example, Japanese Laid-Open Patent Publication No. 2012-169236. The description of the aforementioned publication is incorporated herein by reference. In addition, the organic EL element 200 is continuously laminated with the long-length circular polarizing plate 1 in a roll-to-roll process, and an organic EL display device is continuously manufactured.

In addition, the details of the flexible organic EL display device are described in, for example, Japanese Patent No. 4601463 or Japanese Patent No. 4707996. These records are incorporated herein by reference.

In addition, in the display panel 20, the aspect in which the organic EL element 200 is used is exemplified, but the display device 10 to which the present invention is applied may be, for example, "including a liquid crystal display element." The display panel 20" and the "circular polarizing plate 1 disposed on the viewing side of the display panel 20" are in a state.

The display device 10 of the present embodiment also includes a bent state (a state of being fixed in a curved state) as shown in FIGS. 4A to 4D. In addition, FIGS. 4A to 4D are diagrams for explaining the bending state of the display device 10.

Specifically, the display device 10 can be bent at the center portion by, for example, a folding type as shown in FIGS. 4A and 4B. Further, from the viewpoint of maximizing the design and display screen, as shown in Figs. 4C and 4D, it is also possible to bend at the end.

Further, as shown in FIGS. 4A to 4D, the display device 10 may be curved along the longitudinal direction thereof or may be curved along the short side direction thereof. That is, the display device 10 may be configured to bend a specific portion (for example, one or all of the four corners in an oblique direction) in accordance with the use thereof.

At least a part of the display device 10 is preferably bent with a radius of curvature (bending radius) of 10 mm or less, more preferably 8 mm or less, still more preferably 4 mm or less. In the display device 10 of the present embodiment, the hue (hue) change of the reflected light is reduced in a state of being curved with such a very small radius of curvature, and wrinkles are not easily generated in the circularly polarizing plate 1. Further, the lower limit of the bending radius is not particularly limited and may be 0 mm or more than 0 mm.

The relationship between the bending direction of the display device 10 (the direction orthogonal to the bending start line L) and the absorption axis direction of the polarizer 2, and the slow axis direction of the λ/2 plate 3 will be described with reference to Figs. 5(a) and 5(b). Relationship with the slow axis direction of the λ/4 plate 4. 5(a) and 5(b) are for explaining the relationship between the bending direction of the display device 10 and the absorption axis direction of the polarizing member 2, and the slow axis direction of the λ/2 plate 3 and the λ/4 plate 4. Schematic diagram of the relationship of the slow axis direction. In addition, in the fifth (a) and (b), the absorption axis direction of the polarizer 2 is indicated by "dotted line", and the slow axis direction of the λ/2 plate 3 is represented by "a little chain line", λ/4 plate. The slow axis direction of 4 is indicated by "solid line".

As shown in Fig. 5 (a) and (b), the display device 10 has at least a flat portion 10a and a curved portion 10b which is a linear bending start line L located at the end of the flat portion 10a (5th) The two-dot chain line shown in Figs. (a) and (b) starts and is curved in a direction (curvature direction) orthogonal to the bending start line L. At this time, when the display device 10 is viewed from the normal direction of the flat portion 10a (the Z-axis direction in FIGS. 5(a) and 5(b)), the bending direction of the display device 10 corresponds to a linear bending. The direction in which the line L is orthogonal (the Y-axis direction in FIGS. 5(a) and (b)).

In the display device 10 of the present embodiment, when the counterclockwise direction is positive, the bending direction of the display device 10 is set to -10° to 10° with respect to the slow axis direction (0°) of the λ/4 plate 4 . (Fig. 5 (a) is 0°) or 80° to 100° (Fig. 5 (b) is 90°), preferably set to a range of -5° to 5° or 85° to 95° More preferably, it is set to 0° or 90°.

At this time, the slow axis direction of the λ/2 plate 3 is set to an angle α with respect to the absorption axis direction of the polarizer 2. In other words, the circularly polarizing plate 1 is placed on the surface of the display panel 20 such that the slow axis direction of the λ/2 plate 3 becomes the angle α with respect to the absorption axis direction of the polarizer 2.

Further, the slow axis direction of the λ/4 plate 4 is set to an angle β with respect to the absorption axis direction of the polarizer 2. In other words, the circularly polarizing plate 1 is placed on the surface of the display panel 20 such that the slow axis direction of the λ/4 plate 4 becomes the angle β with respect to the absorption axis direction of the polarizer 2. Further, the angle α and the angle β are both angles based on the absorption axis of the polarizer 2 and counterclockwise directions. Regarding the angle β , when the counterclockwise direction is set to be positive, the slow axis direction of the λ/4 plate 4 is set at -20° to 20° with respect to the absorption axis direction (0°) of the polarizer 2 (Fig. 5) (a), (b) is a range of -15 °).

Specifically, a preferred combination of the angle α and the angle β will be described. The angle α is preferably -80° to -70°, more preferably -78° to -70°, and still more preferably -76° to -70°. At this time, the angle β is preferably -20° to -10°, more preferably -18° to -10°, and still more preferably -16° to -10°.

Further, the angle α is preferably 80° to 70°, more preferably 78° to 70°, and still more preferably 76° to 70°. At this time, the angle β is preferably 20° to 10°, more preferably 18° to 10°, and still more preferably 16° to 10°.

With the slow axis direction so as to be the way to adjust range λ / 2 plate 3 of the slow axis direction (angle [alpha]) and the λ / 4 plate of 4 (angle β), it is possible to suppress the color change results from the bending.

Further, in the circularly polarizing plate 1 of the present embodiment, it is preferable that the hue of the reflected light obtained before and after the bending does not cross the a* coordinate axis in the a*b* chromaticity coordinate of the CIE1976L*a*b* color space and The b* coordinate axis changes. That is, the hue of the reflected light obtained by the SCE method obtained before and after the bending is preferably set so as not to cross the a* coordinate axis in the a*b* chromaticity coordinate and not to cross the value of the b* coordinate axis. Thereby, even if the hue of the reflected light obtained before and after the bending changes, the change in the hue can be made inconspicuous. For example, it is possible to control it so as not to cross the coordinate axes by adjusting the hue of the polarizing plate or adjusting the phase difference of the phase difference layer.

Furthermore, adjusting the wavelength dispersion of the retardation film is also effective for controlling the hue. For example, when the phase difference value of the circularly polarizing plate 1 is increased, the a* value and the b* value become lower, and when the phase difference value of the circularly polarizing plate 1 is lowered, the a* value and the b* value become higher.

Further, before and after the start of the bending, even if at least one of the a* value and the b* value is 0 but the other symbol does not change, it means that there is no change in the symbol before and after the bending. That is, this situation is considered to not cross the a* coordinate axis and the b* coordinate axis. Furthermore, the bending method at the time of performing this evaluation can be based on the method described in the examples below.

The measurement of the reflected hue can be carried out using CM-2600d (a spectrophotometer manufactured by KONICA MINOLTA Co., Ltd.). According to "JIS Z 8722:2009", the setting conditions can be set as follows.

‧Light source: D65 light source

‧Measurement diameter: 8mm

‧Field of view: 2°

‧Geometry conditions: geometric conditions c

In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the invention.

For example, the input mode of the display device 10 described above may be configured to include a touch sensor. Specifically, the display device 30 shown in FIG. 6 may be configured to include the touch sensor 40 and the window film 50 in addition to the configuration of the display device 10. In addition, FIG. 6 is a cross-sectional view showing another configuration example of the flexible display device 30 including the circular polarizing plate 1.

In the display device 30 shown in FIG. 6, the touch sensor 40 is preferably disposed on the side of the circular polarizing plate 1 facing the display panel 20. The window film 50 is preferably disposed on the surface of the circular polarizing plate 1. The side of the display panel 20 is the opposite side. When the circular polarizing plate 1 is present on the viewing side of the touch sensor 40, the pattern of the touch sensor 40 becomes difficult to view, and the visibility of the image displayed on the display panel 20 is improved, which is preferable.

Therefore, in the display device 30 shown in FIG. 6, the display panel 20, the touch sensor 40, the circular polarizing plate 1, and the window film 50 are sequentially laminated using an adhesive or an adhesive. Composition. Further, at least one surface of any of the window film 50, the circular polarizing plate 1, and the touch sensor 40 may be provided with a light shielding pattern to be described later.

In addition, the order of stacking the touch sensor 40 and the window film 50 is not necessarily limited to the above configuration. For example, the display panel 20, the circular polarizing plate 1, the touch sensor 40, and the window may be sequentially disposed. The film 50 is formed by lamination.

Further, the window film 50 may be a protective film 5 constituting the circular polarizing plate 1, and the window film 50 may be configured as a protective film 5 of the circular polarizing plate 1.

Further, in the present invention, although not shown, in addition to the configuration of the display device 10, the touch sensor 40 may be provided on the side opposite to the side facing the display panel 20 of the circularly polarizing plate 1. The composition.

(window film)

The window film 50 is disposed on the viewing side of the flexible display device 30 and functions as a protective layer to protect other components from environmental changes such as flushing or temperature and humidity from the outside. In the past, such a protective layer used glass, but the window film 50 in the flexible display device 30 was not as rigid as glass, but had a bendable property.

The window film 50 has a flexible transparent substrate 51 and a hard coat layer 52 provided on at least one side of the transparent substrate 51. In the display device 30 shown in Fig. 6, the hard coat layer 52 constituting the window film 50 is provided on the surface of the transparent substrate 51 opposite to the circular polarizing plate 1. This hard coat layer 52 serves as the outermost layer of the display device 30 and is in contact with the outside air (air). Further, the hard coat layer 52 may be provided on the side of the circular polarizing plate 1 of the transparent substrate 51. Further, the hard coat layer 52 may be provided only on one side of the transparent substrate 51 or on both sides of the transparent substrate 51.

(transparent substrate)

The transparent substrate 51 has a visible light transmittance of 70% or more, preferably 80% or more. Further, the transparent substrate 51 has a thickness of 5 to 200 μm, preferably 20 to 100 μm.

Any transparent substrate 51 can be used as long as it is a polymer film having transparency. Specific examples thereof include polyolefins such as polyethylene, polypropylene, polymethylpentene, and cycloolefin derivatives having a monomer unit of norbornene or a cyclic olefin, cellulose diacetate, and triacetate fibers. Acrylic acid such as cellulose, cellulose propionate, etc., such as acrylic acid, methyl methacrylate (co)polymer, etc., polystyrene such as styrene (co)polymer, acrylonitrile/butadiene/benzene Ethylene copolymers, acrylonitrile/styrene copolymers, ethylene-vinyl acetate copolymers, polyvinyl chlorides, polyvinylidene chlorides, polyethylene terephthalate, polybutylene terephthalate Polyesters such as diesters, polyethylene naphthalates, polycarbonates, polyarylates, polyamines such as nylons, polyimines, polyamidiamines, polyetherimines A film formed of a polymer such as a polyether oxime, a polyfluorene, a polyvinyl alcohol, a polyvinyl acetal, a polyurethane, or an epoxy resin. Further, such unstretched films, uniaxially stretched films or 2-axis stretched films can be used.

In the transparent substrate 51, these polymers may be used alone or in combination of two or more. In the transparent substrate 51, a polyamide film, a polyimide film, a polyimide film, a polyester film, an olefin film, or an acrylic film which is excellent in transparency and heat resistance is preferably used. , cellulose film.

In the polymer film, it is also preferred to disperse inorganic particles such as cerium oxide, organic fine particles, rubber particles, and the like. Further, it may contain a coloring agent such as a pigment and a dye, a fluorescent whitening agent, a dispersing agent, a plasticizer, a heat stabilizer, a light stabilizer, an infrared absorbing agent, an ultraviolet absorber, an antistatic agent, an antioxidant, A compounding agent such as a slip agent or a solvent.

(hard coating)

The thickness of the hard coat layer 52 is not particularly limited, and is, for example, preferably 2 to 100 μm. When the thickness of the hard coat layer 52 is less than 2 μm, it becomes difficult to ensure sufficient scratch resistance. On the other hand, when the thickness of the hard coat layer 52 exceeds 100 μm, there is a problem in that the bending resistance is lowered and curling occurs due to hardening and shrinkage. In other words, when the thickness of the hard coat layer 52 is 2 μm or more, it is easy to ensure sufficient scratch resistance. In addition, when the thickness of the hard coat layer 52 is 100 μm or less, the problem that the bending resistance is lowered and the curling occurs due to the hardening shrinkage is less likely to occur.

The hard coat layer 52 can be formed by hardening a hard coat composition containing a reactive material forming a crosslinked structure by irradiation with an active energy ray or heat energy, and is preferably hardened by irradiation with an active energy ray.

The active energy ray is defined as the energy line that produces an active species by decomposing a compound that produces an active species. Examples of the active energy rays include visible light, ultraviolet light, infrared light, X-rays, alpha rays, beta rays, gamma rays, and electron beams. Among them, the best is ultraviolet light.

The hard coat layer composition contains at least one polymer of a radical polymerizable compound and a cationically polymerizable compound. The radically polymerizable compound means a compound having a radical polymerizable group. The radical polymerizable group which the radical polymerizable compound has may be a functional group which can undergo a radical polymerization reaction, and examples thereof include a group containing a carbon-carbon unsaturated double bond. Specifically, a vinyl group, a (meth) acryl fluorenyl group, etc. are mentioned.

Further, when the radically polymerizable compound has two or more radical polymerizable groups, the radical polymerizable groups may be the same or different. The number of the radical polymerizable groups which are contained in one molecule of the radical polymerizable compound is preferably two or more from the viewpoint of the hardness of the hard coat layer 52.

From the viewpoint of high reactivity, the radically polymerizable compound is preferably a compound having a (meth) acrylonitrile group, and it is preferred to use a group having 2 to 6 (meth) acrylonitrile groups in one molecule. A compound called a polyfunctional acrylate monomer or an epoxy (meth) acrylate or an urethane (meth) acrylate, which is called a polyester (meth) acrylate, has several in the molecule ( The methyl group has a molecular weight of from several hundreds to several thousands of methacrylic groups. It is preferred to contain one or more selected from the group consisting of epoxy (meth) acrylate, urethane (meth) acrylate, and polyester (meth) acrylate.

The cationically polymerizable compound refers to a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group or a vinyl ether group. The number of cationically polymerizable groups in one molecule of the cationically polymerizable compound is preferably two or more, and more preferably three or more, from the viewpoint of the hardness of the hard coat layer 52. Further, the cationically polymerizable compound is preferably a compound having at least one of an epoxy group and an oxetanyl group as a cationically polymerizable group.

From the viewpoint that the shrinkage of the polymerization reaction is small, a cyclic ether group such as an epoxy group or an oxetanyl group is preferred. Further, among the cyclic ether groups, the compound having an epoxy group is a compound which can easily obtain various structures, does not adversely affect the durability of the obtained hard coat layer 52, and is compatible with a radical polymerizable compound. Compatibility is also easy to control and so on.

Further, in the cyclic ether group, the oxetane group has a network formation rate which is easy to increase the degree of polymerization and has low toxicity and is obtained from the cationically polymerizable compound of the obtained hard coat layer 52 as compared with the epoxy group. There is also no advantage that unreacted monomers remain in the film and form an independent network in the region mixed with the radical polymerizable compound.

The cationically polymerizable compound having an epoxy group may, for example, be a polyglycidyl ether of a polyhydric alcohol having an alicyclic ring or a compound containing a cyclohexene ring or a cyclopentene ring. An alicyclic epoxy resin obtained by epoxidation of a suitable oxidizing agent such as hydrogen peroxide or peracid; a polyepoxypropyl ether of an aliphatic polyol or an alkylene oxide adduct thereof, and an aliphatic long chain poly An aliphatic epoxy resin such as a polyepoxypropyl ester of acid, a homopolymer or a copolymer of glycidyl (meth)acrylate; a bisphenol such as bisphenol A, bisphenol F or hydrogenated bisphenol A; Or a glycidyl ether produced by reacting a derivative such as an alkylene oxide adduct or a caprolactone adduct with epichlorohydrin or the like, and a novolac epoxy resin, etc. A phenol-derived epoxy propyl ether type epoxy resin or the like.

The hard coat composition may further contain a polymerization initiator. The polymerization initiator may, for example, be a radical polymerization initiator, a cationic polymerization initiator, a radical, a cationic polymerization initiator, or the like, and may be appropriately selected and used therefrom. These polymerization initiators are decomposed by at least one of irradiation with an active energy ray and heating to generate radicals or cations for radical polymerization and cationic polymerization.

The radical polymerization initiator may be one which releases free radical polymerization by any of irradiation with an active energy ray and heating. For example, examples of the thermal radical polymerization initiator include organic peroxides such as hydrogen peroxide and peroxybenzoic acid, and azo compounds such as azobisbutyronitrile.

The active energy ray radical polymerization initiator is a first type radical polymerization initiator which generates a radical by decomposition of a molecule, and a first type of radical copolymer which coexists with a ternary amine and generates a radical by hydrogen abstraction reaction. The type 2 radical polymerization initiators may be used singly or in combination.

The cationic polymerization initiator may be one which releases cation polymerization by at least one of irradiation with an active energy ray and heating. As the cationic polymerization initiator, an aromatic onium salt, an aromatic onium salt, a cyclopentadienyl iron (II) complex or the like can be used. These may be initiated by any one or any of the active energy ray irradiation or heating depending on the structure.

The polymerization initiator may be contained in an amount of 0.1 to 10% by weight based on the entire (100% by weight) of the hard coat composition. When the content of the polymerization initiator is less than 0.1% by weight, the hardening cannot be sufficiently performed, and the finally obtained coating film is difficult to achieve mechanical properties and adhesion. On the other hand, when the content of the polymerization initiator exceeds 10% by weight, there are cases where the adhesion is poor, the cracking phenomenon, and the curling phenomenon due to the hardening shrinkage. In other words, when the content of the polymerization initiator is 0.1% by weight or more, the curing can be sufficiently performed, and the finally obtained coating film can easily achieve mechanical properties and adhesion. On the other hand, when the content of the polymerization initiator is 10% by weight or less, the adhesion force due to the hardening shrinkage, the cracking phenomenon, and the curling phenomenon are less likely to occur.

The hard coat composition may further contain one or more selected from the group consisting of a solvent and an additive. Since the solvent can dissolve or disperse the polymerizable compound and the polymerization initiator, it is known as a solvent for the hard coat composition in the art, and can be used without limitation. The additive may further contain inorganic particles, a leveling agent, a stabilizer, a surfactant, an antistatic agent, a lubricant, an antifouling agent, and the like.

(touch sensor)

The touch sensor 40 has been proposed in various forms such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and a capacitance method. Among them, the electrostatic capacity method is preferred.

The electrostatic capacitance type touch sensor 40 is divided into an active area and an inactive area located in the outer portion of the active area. The active area corresponds to an area of "the area (display portion) on which the screen is displayed on the display panel 20", which is an area in which the user is perceived to be touched. On the other hand, the inactive area corresponds to the area of the area (non-display portion) in which the screen is not displayed on the display panel 20.

The touch sensor 40 may include: a substrate having flexible characteristics, a sensing pattern formed on an active region of the substrate, and an inactive region formed on the substrate and connecting the sensing pattern to an external driving circuit via the pad portion Each sensor line. The substrate constituting the touch sensor 40 can usually be made of a polymer material.

The substrate having the flexible property can be made of the same material as the transparent substrate 51 of the window film 50. The substrate of the touch sensor 40 preferably has a toughness of 2000 MPa% or more from the viewpoint of suppressing cracks. More preferably, the toughness is from 2,000 to 30,000 MPa%.

Further, the toughness of the substrate is defined as "the stress (MPa) [vertical axis] obtained by the tensile test of the polymer material constituting the substrate, and the strain (%) [horizontal axis] is plotted. A Stress-strain curve is obtained, in which the area under the curve to the point of failure is ". From the viewpoint of suppressing the crack of the touch sensor 40, it is desirable that the substrate constituting the touch sensor 40 has the toughness in the above range.

The sensing pattern may include a first pattern formed in the first direction and a second pattern formed in the second direction. The first pattern and the second pattern are arranged in directions different from each other. If the first pattern and the second pattern are to be formed on the same layer and the touched place is sensed, each pattern must be electrically connected.

The first pattern is a form in which each unit pattern is connected to each other via a joint. On the other hand, the second pattern is a structure in which each unit pattern is separated into an island shape. Therefore, in order to electrically connect the second pattern, it is necessary to have another bridge electrode.

The sensing pattern can be applied to well-known transparent electrode materials. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), PEDOT (poly(3,4-ethylenedioxythiophene), That is, poly(3,4-extended ethyldioxythiophene), carbon nanotubes (CNT), graphene, metal wires, and the like. Further, these may be used alone or in combination of two or more. Among them, ITO is preferably used.

The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, tellurium, chromium, and the like. Further, these may be used alone or in combination of two or more.

The bridge electrode may be formed on the upper portion of the sensing pattern via an insulating layer. Furthermore, a bridge electrode can be formed on the substrate, and an insulating layer and a sensing pattern can be formed thereon.

The bridge electrode may also be formed of the same material as the sensing pattern. For example, it may be formed of a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium or two or more of these alloys. .

Since the first pattern and the second pattern must be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joint of the first pattern and the bridge electrode, or may be formed on the layer covering the sensing pattern. In the latter case, the bridge electrode is connected to the second pattern via a contact hole formed in the insulating layer.

In the touch sensor 40, an optical adjustment layer may be further included between the substrate and the electrode, and the optical adjustment layer is used to appropriately compensate between the "patterned pattern region and the non-pattern region where the pattern is not formed. The difference between the transmittances (specifically, "the difference in light transmittance induced by the difference in refractive index in these regions").

The optical adjustment layer may contain an inorganic insulating material or an organic insulating material. The optical adjustment layer can be formed by applying a photocurable composition containing a photocurable organic binder and a solvent onto a substrate. The photohardenable composition may further contain inorganic particles. The refractive index of the optical adjustment layer can be raised by the inorganic particles.

The photocurable organic binder may contain a copolymer of each monomer such as an acrylate monomer, a styrene monomer, or a carboxylic acid monomer. The photocurable organic binder may be, for example, a copolymer containing repeating units containing an epoxy group, an acrylate repeating unit, a carboxylic acid repeating unit, and the like, which are different from each other.

The inorganic particles may contain, for example, zirconia particles, titanium oxide particles, alumina particles, or the like. The photohardening composition may further contain each additive such as a photopolymerization initiator, a polymerizable monomer, and a curing assistant.

(adhesive)

As the subsequent agent, a water-based adhesive, an organic solvent-based adhesive, a solvent-free adhesive, a solid adhesive, a solvent-volatile adhesive, a moisture-curing adhesive, a heat-curing adhesive, and an anaerobic adhesive can be used. An active energy ray-curable adhesive, a curing agent-mixing adhesive, a hot-melt adhesive, a pressure-sensitive adhesive (adhesive), a rewet-type adhesive, and the like. Among them, a water-based adhesive, an active energy ray-curable adhesive, and the like are often used. Further, as the water-based adhesive or the active energy ray-curable adhesive, the above may be used.

(adhesive)

In the case of the adhesive, any one of an acrylic adhesive, an urethane adhesive, a rubber adhesive, and a polyoxygen adhesive may be used depending on the main polymer. . In the adhesive, in addition to the main polymer, a crosslinking agent, a decane compound, an ionic compound, a crosslinking catalyst, an antioxidant, an adhesion-imparting agent, a plasticizer, a dye, a pigment, an inorganic filler, or the like may be blended.

The adhesive composition is obtained by dissolving and dispersing the components constituting the adhesive in a solvent, and the adhesive composition is applied onto a substrate and dried to form an adhesive layer. The adhesive layer may be formed directly, or may be additionally transferred on the substrate.

If it is desired to cover the adhesive surface before the film, it is preferred to use a release film. The thickness of the adhesive layer when the active energy ray-curable adhesive is used is 0.1 to 500 μm, preferably 1 to 300 μm. When a plurality of layers of adhesive are used, the thickness and type of each layer may be the same or different.

(shading pattern)

The shading pattern can be applied to at least a portion of a bezel or housing that is a bendable display device 30. The wiring disposed at the edge portion of the flexible display device 30 is hidden by the light-shielding pattern so that it is not easily viewed, whereby the visibility of the image can be improved.

The light shielding pattern may be in the form of a single layer or a plurality of layers. The color of the light-shielding pattern is not particularly limited, and may have various colors such as black, white, and metallic colors. The light-shielding pattern can be formed of a pigment for realizing color, a polymer such as an acrylic resin, an ester resin, an epoxy resin, a polyurethane, or a polyfluorene. Further, these or the like may be used alone or in combination of two or more.

The light shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The light shielding pattern has a thickness of from 1 μm to 100 μm, preferably from 2 μm to 50 μm. Further, it is also preferable to impart a shape such as inclination in the thickness direction of the light shielding pattern.

[Examples]

Hereinafter, the effects of the present invention will be explained based on the examples. In addition, the present invention is not limited to the following embodiments, and modifications may be appropriately made without departing from the spirit and scope of the invention.

[Example 1]

(production of polarizer)

After dyeing a long-sized polyvinyl alcohol film in an aqueous solution containing iodine, the aqueous solution containing boric acid is uniaxially stretched six times between rolls having different rotation speed ratios to obtain a long-length having an absorption axis in the longitudinal direction. Polarizer. The long-length polarizer is stretched into a wound body after being stretched. The chromaticity of the polarizer is orthogonal to a=0.04, orthogonal b=-0.11, the visual sensitivity of the polarizer is corrected to about 99.995%, and the visual sensitivity of the polarizer is corrected to 42.7%.

(protective film)

A long-size cellulose triacetate film (thickness: 40 μm, manufactured by KONICA MINOLTA Co., Ltd., trade name: KC4UYPURE ACE) was used as a protective film. This protective film is prepared in the form of a wound body. Further, the in-plane retardation value Re (550) of the protective film was 5 nm, and the retardation value Rth (550) in the thickness direction was 45 nm.

(λ/2 board)

As the λ/2 plate, a film containing a layer hardened by a liquid crystal compound and an alignment film was used.

(λ/4 board)

As the λ/4 plate, a film containing a layer hardened by a liquid crystal compound and an alignment film was used.

(UV curing adhesive)

The following components were mixed and defoamed to prepare an ultraviolet curable adhesive.

3,4-epoxycyclohexanecarboxylic acid 3',4'-epoxycyclohexylmethyl ester (trade name: CEL2021P, manufactured by DAICEL Co., Ltd.): 70 parts by mass

Neopentyl glycol diepoxypropyl ether (trade name: EX-211, manufactured by NAGASE CHEMTEX Co., Ltd.): 20 parts by mass

2-ethylhexylepoxypropyl ether (trade name: EX-121, manufactured by NAGASE CHEMTEX Co., Ltd.): 10 parts by mass

Cationic polymerization initiator (trade name: CPI-100, manufactured by SAN-APRO Co., Ltd.): solid content of 2.25 parts by mass (adapted into 50% propylene carbonate solution)

1,4-diethoxynaphthalene: 2 parts by mass

(Production of circular polarizer)

After the polarizer, the protective film, the λ/2 plate, and the λ/4 plate were cut out by 200 mm × 300 mm, respectively, the protective film was bonded to both surfaces of the polarizer via a polyvinyl alcohol-based adhesive. The λ/2 plate and the λ/4 plate were bonded to each other via the ultraviolet curable adhesive (adhesive layer). Further, the λ/2 plate and the protective film were bonded to each other via an acrylic pressure-sensitive adhesive layer (PSA layer). An acrylic adhesive layer (PSA layer) to which a release film is attached is attached to the λ/4 plate.

At the time of bonding, the λ/2 plate is disposed such that its slow axis becomes an angle α of -75° with respect to the absorption axis of the polarizer. At the time of bonding, the λ/4 plate is disposed such that its slow axis becomes an angle β of -15° with respect to the absorption axis of the polarizer. Furthermore, the absorption axis of the polarizer is arranged parallel to the longitudinal direction.

As described above, a circularly polarizing plate in which a protective film, a polarizing material, a protective film, a PSA layer, a λ/2 plate, a UV adhesive layer, a λ/4 plate, and a PSA layer were sequentially laminated was produced. Thereafter, the produced circular polarizing plate was cut into a size of 20 mm × 80 mm.

(production of sample for evaluation)

After removing the release film from the circularly polarizing plate of Example 1, the adhesive surface was attached to a mat surface of an aluminum foil (manufactured by UACJ Co., Ltd., trade name "MYFOIL (registered trademark)"), and was evaluated. Use the sample.

As a result, as shown in Fig. 5(a), the slow axis of the λ/2 plate becomes an angle α of -75° with respect to the absorption axis direction of the polarizer. The slow axis of the λ/4 plate is an angle β of -15° with respect to the absorption axis direction of the polarizer. The bending direction of the circularly polarizing plate is an angle of 0° with respect to the slow axis direction of the λ/4 plate. The bending start line L of the circularly polarizing plate is 75° with respect to the absorption axis direction of the polarizer. The sample for evaluation was obtained in this manner. The obtained evaluation sample was subjected to an evaluation test of color change and wrinkle generation in a state in which the bending state was released (planar state) after bending.

(Measurement of storage elastic modulus of the layer test piece at a temperature of 30 ° C)

First, a coater (a bar coater, manufactured by Daiichi Ryoichi Co., Ltd.) was applied to one surface of a 50 μm-thick ring-shaped polyolefin resin film, and it was applied to fit a λ/2 plate and λ/4. The ultraviolet curable adhesive used for the sheet was further laminated with a cyclic polyolefin resin film having a thickness of 50 μm on the coated surface.

Then, the "H valve" manufactured by FUSION UV SYSTEMS Co., Ltd. was irradiated with ultraviolet rays so that the amount of integrated light became 1500 mJ/cm ² (UVB), and the adhesive layer was cured. The thickness of the subsequent layer was 30 μm. This was cut into a size of 5 mm × 30 mm, and the annular polyolefin resin film on both sides was peeled off to obtain a cured film of an adhesive.

The cured film was subjected to a dynamic viscoelasticity measuring device "DVA-220" manufactured by IT Measurement and Control Co., Ltd., and the clamp interval was set to 2 cm, and the stretched film was stretched. The frequency of shrinkage was set to 10 Hz, the measurement temperature was set to 30 ° C, and the storage elastic modulus at a temperature of 30 ° C was determined. The storage modulus of the layer test piece at a temperature of 30 ° C was 2060 MPa.

(evaluation test)

While pressing a mandrel having a diameter of 5 mm, the evaluation sample was placed along the center so that the bending direction of the display device 10 was 0° with respect to the slow axis direction (0°) of the λ/4 plate. The circumferential surface of the shaft is bent, and the circular polarizing plate is made to the outside (OUT) with respect to the aluminum foil. Then, the circular polarizing plate was visually observed after bending, and the color change was evaluated as "A", and the color change was evaluated as "B". Further, those with less wrinkles were evaluated as "A", and those with more wrinkles were evaluated as "B". The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[Embodiment 2]

In Example 2, the same sample for evaluation as in Example 1 was produced. Then, the sample for evaluation was bent along the circumferential surface of the mandrel, and the circular polarizing plate was made inward (IN) with respect to the aluminum foil. Then, after bending, the same evaluation test as in Example 1 was carried out. The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[Example 3]

In the third embodiment, as shown in FIG. 5(b), the bending direction of the circular polarizing plate is 90°, except that the bending direction of the circular polarizing plate is 90° with respect to the slow axis direction of the λ/4 plate. The evaluation sample similar to that of Example 1 was produced except that the L system was -15° with respect to the absorption axis direction of the polarizer. Then, this evaluation sample was bent under the same conditions as in Example 1. Then, after bending, the same evaluation test as in Example 1 was carried out. The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[Example 4]

In Example 4, the same sample for evaluation as in Example 3 was produced. Then, the sample for evaluation was bent along the circumferential surface of the mandrel, and the circular polarizing plate was made inward (IN) with respect to the aluminum foil. Then, after bending, the same evaluation test as in Example 1 was carried out. The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[Comparative Example 1]

In Comparative Example 1, except that the bending direction of the circularly polarizing plate is 60° with respect to the slow axis direction of the λ/4 plate, the bending start line L of the circularly polarizing plate becomes the direction of the absorption axis of the polarizing member - A test sample similar to that of Example 1 was produced except for 45°. Then, this sample for evaluation was bent under the same conditions as in Example 1. Then, after bending, the same evaluation test as in Example 1 was carried out. The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[Comparative Example 2]

In Comparative Example 2, except that the bending direction of the circularly polarizing plate is an angle of -30 with respect to the slow axis direction of the λ/4 plate, the bending start line L of the circularly polarizing plate is opposed to the absorption axis direction of the polarizing member. A test sample similar to that of Example 1 was produced except that it was 45°. Then, this sample for evaluation was bent under the same conditions as in Example 1. Then, after bending, the same evaluation test as in Example 1 was carried out. The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[Comparative Example 3]

In Comparative Example 3, the same evaluation sample as in Comparative Example 1 was produced except that the λ/2 plate and the λ/4 plate were bonded via an adhesive layer. Then, this sample for evaluation was bent under the same conditions as in Example 1. Then, after bending, the same evaluation test as in Example 1 was carried out. The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[Comparative Example 4]

In Comparative Example 4, the same evaluation sample as in Comparative Example 2 was produced except that the λ/2 plate and the λ/4 plate were bonded via an adhesive layer. Then, this sample for evaluation was bent under the same conditions as in Example 1. Then, after bending, the same evaluation test as in Example 1 was carried out. The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[Comparative Example 5]

In Comparative Example 5, the same sample for evaluation as in Comparative Example 1 was produced. Then, the sample for evaluation was bent along the circumferential surface of the mandrel, and the circular polarizing plate was made inward (IN) with respect to the aluminum foil. Then, after bending, the same evaluation test as in Example 1 was carried out. The results of the evaluation are shown in Table 1 below. Furthermore, the hue of the reflected light obtained before and after the bending changes in the a*b* chromaticity coordinates without crossing the a* coordinate axis and the b* coordinate axis.

[assessment]

As is apparent from Table 1, according to Examples 1 to 4 of the present invention, good results were obtained with respect to the change in hue (hue) and the presence or absence of wrinkles of the reflected light in the curved portion as compared with Comparative Examples 1 to 5. .

Claims (7)

 A circular polarizing plate is used for a flexible display device, the circular polarizing plate includes: a polarizing member; and a phase difference layer disposed on one side of the polarizing member; wherein the polarizing member has a visual sensitivity correcting unit The transmittance is 42% or more; the retardation layer includes a 1/2 wavelength plate and a 1/4 wavelength plate; and the 1/2 wavelength plate and the 1/4 wavelength plate respectively comprise a layer obtained by hardening a liquid crystal compound; When the counterclockwise direction is set to a positive timing, the slow axis direction of the 1/4 wavelength plate is in the range of -20° to 20° from the absorption axis direction of the polarizing member, and is relative to the aforementioned 1/4 wavelength plate. In the slow axis direction, the bending direction of the aforementioned display device is set in the range of 80° to 100° or −10° to 10°.    The circularly polarizing plate according to claim 1, wherein the 1/2 wavelength plate and the 1/4 wavelength plate are followed by an adhesive layer.    The circularly polarizing plate according to claim 1 or 2, wherein the display device is an organic electroluminescence display device.    The circularly polarizing plate according to any one of claims 1 to 3, wherein the hue of the reflected light obtained before and after the bending has a sign in the a*b* chromaticity coordinate that does not cross the a* coordinate axis and b* The coordinate axis changes.    A flexible display device comprising: a circularly polarizing plate according to any one of claims 1 to 4, and a flexible display panel.    The flexible display device according to claim 5, comprising: a touch sensor disposed on a side of the circular polarizing plate facing the display panel; and a front side facing the circular polarizing plate The side of the display panel is the window film disposed on the opposite side.    The flexible display device according to claim 5, further comprising: a touch sensor disposed on a side opposite to a side facing the display panel of the circular polarizing plate.